2 Printed on paper containing at least 30% postconsumer recovered fiber. 
U.S. Environmental Protection Agency 

Office of Water (4303T) 

1200 Pennsylvania Avenue, NW 

Washington, DC 20460 

EPA-821-B-03-001
Development Document For The

Final Effluent Limitations 

Guidelines and Standards 

For The 

Metal Products & Machinery 

Point Source Category

EPA-821-B-03-001 

Christine Todd Whitman 

Administrator

G. Tracy Mehan, III

Assistant Administrator, Office of Water

Geoffrey H. Grubbs

Director, Office of Science and Technology

Sheila E. Frace

Director, Engineering and Analysis Division

Marvin Rubin

Chief, Energy Branch

Shari Z. Barash

Technical Coordinator

Jan S. Matuszko

Technical Coordinator

Carey A. Johnston, P.E.

Project Manager

February 2003

U.S. Environmental Protection Agency
Office of Water 

Washington, DC 20460 

ACKNOWLEDGMENTS AND DISCLAIMER 

The Agency would like to acknowledge the contributions of Shari Barash, Yu-Ting 

Guilaran, Carey Johnston, Jan Matuszko, Marvin Rubin, Marla Smith, and Richard Witt to 

development of this technical document. In addition, EPA acknowledges the contribution of 

Eastern Research Group, Westat, Abt Associates, and Science Applications International 

Corporation. 

Neither the United States government nor any of its employees, contractors, 

subcontractors, or other employees makes any warranty, expressed or implied, or assumes any 

legal liability or responsibility for any third party’s use of, or the results of such use of, any 

information, apparatus, product, or process discussed in this report, or represents that its use by 

such a third party would not infringe on privately owned rights. References to proprietary 

technologies are not intended to be an endorsement by the Agency. 

Questions or comments regarding this technical document should be addressed to:

Mr. Carey A. Johnston, P.E.

Environmental Engineer

Engineering and Analysis Division (4303T)

U.S. Environmental Protection Agency

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

(202) 566 - 1014

johnston.carey@epa.gov
Table of Contents 

TABLE OF CONTENTS


Page 

1.0	 SUMMARY AND SCOPE OF THE REGULATION ........................... 1-1


1.1 Overview of the MP&M Point Source Category .................. 1-1


1.2 Overlap with Other Effluent Guidelines ........................ 1-5


1.3 Summary of Applicability ................................... 1-7


1.4 Promulgated Effluent Limitations Guidelines and Standards ........ 1-8


1.5 Protection of Confidential Business Information .................. 1-9


2.0 BACKGROUND .................................................. 2-1


2.1 Legal Authority ........................................... 2-1


2.2 Regulatory Background ..................................... 2-1


2.2.1 Clean Water Act ..................................... 2-1


2.2.2 Section 304(m) Requirements .......................... 2-5


2.2.3 Pollution Prevention Act .............................. 2-5


2.2.4 Regulatory Flexibility Act (RFA) as Amended by the


Small Business Regulatory Enforcement Fairness Act of 1996


(SBREFA) ......................................... 2-6


2.2.5 Regulatory History of the Metals Industry ................. 2-8


3.0	 DATA COLLECTION ACTIVITIES ..................................... 3-1


3.1 Industry Questionnaires ..................................... 3-1


3.1.1 

3.1.2 

3.1.3 

3.1.4 

3.1.5 

The 1989 Industry Surveys ............................ 3-2


3.1.1.1 1989 Screener Survey .......................... 3-2


3.1.1.2 1989 Detailed Survey ........................... 3-8


The 1996 Industry Surveys ........................... 

3.1.2.1 1996 Screener Survey ......................... 

3.1.2.2 1996 Long Detailed Survey ..................... 

3.1.2.3 1996 Short Detailed Survey ..................... 

3.1.2.4 1996 Municipality Detailed Survey ............... 

3.1.2.5 1996 Federal Facilities Detailed Survey ........... 

3.1.2.6 1996 POTW Detailed Survey ................... 

1997 Iron and Steel Industry Survey Data ................ 

Data Submitted by the American Association of Railroads 

(AAR) ........................................... 

National Estimates .................................. 

3-12


3-13


3-16


3-19


3-21


3-23


3-25


3-26


3-32


3-33


3-34


3-35


3-38


3-38


3-39


3-40


3.2	 Site Visits ............................................... 

3.2.1 Criteria for Site Selection ............................. 

3.2.2 Information Collected ............................... 

3.3	 EPA MP&M Sampling Program ............................. 

3.3.1 Criteria for Site Selection ............................. 

3.3.2 Information Collected ............................... 

i

Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

3.3.3 Sample Collection and Analysis .......................


3.4 Other Sampling Data ......................................


3.5 Other Industry-Supplied Data ...............................


3.6 Other Data Sources .......................................


3.6.1


3.6.2


3.6.3 

3.6.4


3.6.5


3.6.6


EPA/EAD Databases ................................


Fate of Priority Pollutants in Publicly Owned Treatment


Works Database ....................................


National Risk Management Research Laboratory (NRMRL)


Treatability Database ................................


The Domestic Sewage Study ..........................


Toxics Release Inventory (TRI) Database ................


Discharge Monitoring Reports from EPA’s Permit


Compliance System .................................


3-41 

3-46 

3-48 

3-49 

3-50 

3-50 

3-51 

3-51 

3-52 

3-52 

3.7 References ..............................................
3-53

INDUSTRY DESCRIPTION ...........................................
4-1 

4.1	 Overview of MP&M facilities ................................ 4-1


4.1.1 Number and Size of MP&M Facilities ................... 4-2


4.1.2 Geographic Distribution ............................... 4-3


4.1.3 Wastewater-Discharging Facilities ...................... 4-4


4.1.4 Non-Wastewater-Discharging Facilities .................. 4-9


4.2	 Proposed MP&M Operations ................................ 4-11


4.2.1 Types of Unit Operations ............................. 4-12


4.2.2 Description of Proposed MP&M Operations ............. 4-14


4.2.2.1 Description of MP&M Oily Operations ............ 4-17


4.2.2.2 Description of MP&M Metal-bearing Operations .... 4-22


4.2.3 Metals Processed ................................... 4-34


4.2.4 Estimated Annual Wastewater Discharge ................ 4-34


4.3 Trends in the Industry ..................................... 4-41


4.4 References .............................................. 4-41


5.0	 WASTEWATER CHARACTERISTICS ................................... 5-1


5.1 Process Water and Rinse Water .............................. 5-1


5.2 Influent to Oily Wastewater Treatment Systems ................. 5-13


6.0 INDUSTRY SUBCATEGORIZATION .................................... 6-1


6.1 Methodology and Factors Considered for Basis of Subcategorization . 6-1


6.1.1 Factors Contributing to the Subcategorization Structure


Evaluated for the Final Rule ........................... 6-2


6.1.2 Factors That are Not a Basis For MP&M Subcategorization . 6-13


ii 

4.0 
Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

6.2	 General Description of Facilities in Each Subcategory Evaluated 

for the Final Rule ......................................... 6-17 

6.2.1 General Metals Subcategory Evaluated for the Final Rule ... 6-17 

6.2.2 Metal Finishing Job Shops Subcategory Evaluated for the 

Final Rule ......................................... 6-19 

6.2.3 Non-Chromium Anodizing Subcategory Evaluated for the 

Final Rule ......................................... 6-19 

6.2.4 Printed Wiring Board Subcategory Evaluated for the Final 

Rule ............................................. 6-20 

6.2.5 Steel Forming and Finishing Subcategory Evaluated for the 

Final Rule ......................................... 6-20 

6.2.6 Oily Wastes Subcategory ............................. 6-20 

6.2.7 Railroad Line Maintenance Subcategory Evaluated for the 

Final Rule ......................................... 6-22 

6.2.8 Shipbuilding Dry Dock Subcategory .................... 6-23 

SELECTION OF POLLUTANT PARAMETERS
 ............................. 7-1


7.1 Identification of Pollutants of Concern ......................... 7-1


7.2 Regulated Pollutants ...................................... 7-12


7.3 References .............................................. 7-14


8.0 POLLUTION PREVENTION PRACTICES AND WASTEWATER


TREATMENT TECHNOLOGIES ....................................... 8-1


8.1 Flow Reduction Practices ................................... 8-1


8.1.1 Rinse Tank Design and Innovative Configurations .......... 8-2


8.1.2 Additional Design Elements ........................... 8-7


8.1.3 Rinse Water Use Control .............................. 8-8


8.1.4 Pollution Prevention for Process Baths ................... 8-9


8.2 In-Process Pollution Prevention Technologies ................... 8-9


8.2.1


8.2.2


8.2.3


8.2.4


8.2.5


8.2.6


8.2.7


8.2.8


Activated Carbon Adsorption .........................


Carbonate “Freezing” ................................


Centrifugation and Pasteurization of Machining Coolants ...


Centrifugation and Recycling of Painting Water Curtains ...


Electrodialysis .....................................


Electrolytic Recovery ................................


Evaporation .......................................


Filtration ..........................................


8.2.8.1 Ion Exchange (in-process) ......................


8.2.8.2 Reverse Osmosis .............................


8.3	 Best Management Practices and Environmental Management


Systems for Pollution Prevention .............................


8-12 

8-13 

8-13 

8-14 

8-16 

8-17 

8-19 

8-20 

8-21 

8-24 

8-25 

iii 

7.0 
Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

8.3.1 Pollution Prevention for Cleaning and Degreasing 

Operations ........................................ 8-27


8.3.2 Pollution Prevention for Machining Operations ........... 8-28


8.3.3 Painting Operations ................................. 8-29


8.3.4 Pollution Prevention for Printed Wiring Board


Manufacturing ..................................... 8-29


8.4	 Preliminary Treatment of Segregated Wastewater Streams ......... 8-30


8.4.1 Chromium-Bearing Wastewater ....................... 8-31


8.4.2 Concentrated Metal-Bearing Wastewater ................ 8-36


8.4.3 Cyanide-Bearing Wastewater .......................... 8-36


8.4.3.1 Alkaline Chlorination .......................... 8-37


8.4.3.2 Ozone Oxidation ............................. 8-38


8.4.4	 Chelated-Metal-Bearing Wastewater .................... 8-39


8.4.4.1 Reduction to Elemental Metal ................... 8-39


8.4.4.2 Precipitation as an Insoluble Compound ........... 8-40


8.4.4.3 Physical Separation ........................... 8-41


8.4.5	 Oil-Bearing Wastewater .............................. 8-41


8.4.5.1 Chemical Emulsion Breaking ................... 8-42


8.4.5.2 Oil Skimming ................................ 8-44


8.4.5.3 Flotation of Oils or Solids ...................... 8-46


8.4.5.4 Ultrafiltration ................................ 8-47


8.5	 End-of-Pipe Wastewater Treatment and Sludge-Handling


Technologies ............................................ 8-48


8.5.1 Chemical Precipitation for Metals Removal .............. 8-48


8.5.1.1 Gravity Clarification for Solids Removal .......... 8-54


8.5.1.2 Microfiltration for Solids Removal ............... 8-55


8.5.1.3 Optimization of Existing Chemical Precipitation


Treatment System ............................ 8-56


8.5.2 Oil Removal ....................................... 8-57


8.5.3 Polishing Technologies .............................. 8-58


8.5.3.1 Multimedia Filtration .......................... 8-58


8.5.3.2 Activated Carbon Adsorption ................... 8-59


8.5.3.3 Reverse Osmosis ............................. 8-59


8.5.3.4 Ion Exchange ................................ 8-59


8.5.4	 Sludge Handling .................................... 8-60


8.5.4.1 Gravity Thickening ........................... 8-60


8.5.4.2 Pressure Filtration ............................ 8-61


8.5.4.3 Vacuum Filtration ............................ 8-62


8.5.4.4 Sludge Drying ............................... 8-63


8.6 References .............................................. 8-63


iv 
Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

9.0 TECHNOLOGY OPTIONS ........................................... 9-1


9.1 Technology Evaluation Methods .............................. 9-1


9.2 General Metals Subcategory ................................. 9-2


9.2.1 Best Practicable Control Technology Currently Available 

(BPT) ............................................. 9-2


9.2.2 Best Conventional Pollutant Control Technology (BCT) ..... 9-8


9.2.3 Best Available Technology Economically Achievable (BAT) . 9-9


9.2.4 New Source Performance Standards (NSPS) .............. 9-10


9.2.5 Pretreatment Standards for Existing Sources (PSES) ....... 9-11


9.2.6 Pretreatment Standards for New Sources (PSNS) .......... 9-13


9.3 Metal Finishing Job Shops Subcategory ....................... 9-14


9.3.1 BPT, BCT, and BAT ................................ 9-14


9.3.2 NSPS ............................................ 9-15


9.3.3 PSES ............................................ 9-16


9.3.4 PSNS ............................................ 9-17


9.4 Non-Chromium Anodizing Subcategory ....................... 9-18


9.4.1 BPT, BCT, and BAT ................................ 9-18


9.4.2 NSPS ............................................ 9-19


9.4.3 PSES and PSNS .................................... 9-19


9.5 Printed Wiring Board Subcategory ........................... 9-20


9.5.1 BPT, BCT, and BAT ................................ 9-20


9.5.2 NSPS ............................................ 9-20


9.5.3 PSES ............................................ 9-21


9.5.4 PSNS ............................................ 9-22


9.6 Steel Forming and Finishing Subcategory ...................... 9-23


9.6.1 BPT, BCT, and BAT ................................ 9-23


9.6.2 NSPS ............................................ 9-24


9.6.3 PSES ............................................ 9-24


9.6.4 PSNS ............................................ 9-24


9.7 Oily Wastes Subcategory ................................... 9-25


9.7.1 BPT ............................................. 9-25


9.7.2 BCT ............................................. 9-28


9.7.3 BAT ............................................. 9-28


9.7.4 NSPS ............................................ 9-28


9.7.5 PSES ............................................ 9-29


9.7.6 PSNS ............................................ 9-30


9.8 Railroad Line Maintenance Subcategory ....................... 9-31


9.8.1 BPT ............................................. 9-31


9.8.2 BCT ............................................. 9-33


9.8.3 BAT ............................................. 9-34


v 
Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

9.8.4 NSPS ............................................ 9-34


9.8.5 PSES and PSNS .................................... 9-34


9.9	 Shipbuilding Dry Dock Subcategory .......................... 9-35


9.9.1 BPT ............................................. 9-35


9.9.2 PSES and PSNS .................................... 9-36


9.10	 Summary of Technology Options Considered and Selected for the


Final MP&M Rule ........................................ 9-36


10.0	 LIMITATIONS AND STANDARDS: DATA SELECTION AND CALCULATION .... 10-1


10.1 Overview of Data Selection ................................. 10-1


10.2 Episode and Data Selection ................................. 10-2


10.3 Data Aggregation ......................................... 10-9


10.3.1 Aggregation of Field Duplicates ...................... 10-11


10.3.2 Aggregation of Grab Samples ........................ 10-11


10.4	 Overview of Limitations .................................. 10-12


10.4.1 Objective ........................................ 10-12


10.4.2 Selection of Percentiles ............................. 10-13


10.4.3 Compliance with Limitations ......................... 10-14


10.5 Calculation of the Limitations .............................. 10-15


10.6	 Evaluation of the Limitations ............................... 10-16


10.6.1 Comparison to Data ................................ 10-17


10.6.2 Comparison to Proposed and NODA Values ............. 10-21


11.0	 COSTS OF TECHNOLOGY BASES FOR REGULATIONS ..................... 11-1


11.1 Summary of Costs ........................................ 11-1


11.2 Development of Cost Model Inputs ........................... 11-6


11.2.1 Model Site Development ........................... 11-6


11.2.2 Wastewater Streams and Flow Rates .................. 11-7


11.2.3 Wastewater Pollutant Concentrations .................. 11-9


11.2.4 Technology in Place .............................. 11-10


11.2.4.1 Baseline Model Runs ................... 11-15


11.2.4.2 Post-Compliance Model Runs ............ 11-16


11.2.4.3 New Source Model Runs ................ 11-16


11.3	 General Methodology for Estimating Costs of Treatment 


Technologies ........................................... 11-17


11.3.1 Components of Cost .............................. 11-18


11.3.1.1 Total Annualized Costs ................. 11-19


11.3.2 Sources and Standardization of Cost Data ............. 11-20


11.3.3 Development of the Cost Model ..................... 11-25


11.3.3.1 Modeling Technology Options ........... 11-26


11.3.3.2 Modeling Flow Reduction ............... 11-30


vi 
Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

11.3.3.3 Modeling End-of-Pipe Treatment for Metal


Bearing Subcategories .................. 11-30


11.3.3.4 Modeling End-of-Pipe Treatment for Oily


Subcategories ......................... 11-31


11.3.3.5 Model Output ......................... 11-31


11.3.4 General Assumptions Made During the Costing Effort ... 11-31


11.4	 Specific Methodology and Assumptions Used to Estimate Costs for


Treatment Technologies ................................... 11-34


11.4.1 NODA Cost Estimates ............................ 11-35


11.4.2 Post-NODA Cost Estimates ........................ 11-37


11.5	 Costing Methodologies for Direct Discharging Oil-Bearing


Subcategories ........................................... 11-39


11.5.1 Oily Wastes Costing Methodology ................... 11-39


11.5.2 Railroad Line Maintenance Costing Methodology ....... 11-40


11.5.3 Shipbuilding Dry Dock Costing Methodology .......... 11-40


11.6	 Design and Costs of Individual Pollution Control Technologies ... 11-40


11.6.1 Countercurrent Cascade Rinsing ..................... 11-41


11.6.2 Centrifugation and Pasteurization of Machining Coolant . 11-41


11.6.3 Centrifugation of Painting Water Curtains ............ 11-42


11.6.4 Contracting for Off-Site Treatment and Disposal ........ 11-49


11.6.5 Feed Systems and Chemical Dosages ................. 11-49


11.6.6 Chemical Emulsion Breaking and Gravity Oil/Water


Separation ...................................... 11-52


11.6.7 Dissolved Air Flotation ............................ 11-53


11.6.8 Ultrafiltration System for Oil Removal ............... 11-54


11.6.9 Batch Oil Emulsion Breaking with Gravity Flotation ..... 11-54


11.6.10 Chemical Reduction of Hexavalent Chromium ......... 11-55


11.6.11 Cyanide Destruction .............................. 11-56


11.6.12 Chemical Reduction/Precipitation of Chelated Metals ... 11-57


11.6.13 Chemical Precipitation ............................ 11-57


11.6.14 Sedimentation by Slant-Plate Clarifier ................ 11-58


11.6.15 Multimedia Filtration ............................. 11-59


11.6.16 Microfiltration for Solids Removal ................... 11-59


11.6.17 Sludge Thickening ............................... 11-60


11.6.18 Sludge Pressure Filtration .......................... 11-60


11.7 References ............................................. 11-61


vii 
Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

12.0 POLLUTANT LOADING AND REDUCTION ESTIMATES ....................


12.1 Estimation of Unit Operation Wastewater Pollutant Concentrations .


12.1.1 Unit Operation Wastewater Data Collection ............


12.1.2 Calculation of Pollutant Concentrations for Each Unit


Operation for Each Sampling Point from EPA or Industry-


Supplied Sampling Data ............................


12.1.3 Estimation of Pollutant Concentrations for Each


Subcategory and Unit Operation ......................


12.1.3.1 

12.1.3.2 

12.1.3.3 

12.1.3.4 

Identification of Unit Operations Reported in


the Detailed Surveys ....................


Estimation of Wastewater Pollutant


Concentrations for Each Unit Operation/


Subcategory Combination ................


Estimation of Applied Metal Concentrations


Using Available Analytical Data ...........


Modeling of Pollutant Concentrations for


Each Model Site Unit Operation ...........


12.2 Estimation of Industry Baseline Pollutant Loadings ..............


12-1 

12-2 

12-2 

12-3 

12-4 

12-4 

12-5 

12-7 

12-8 

12-9 

12.2.1 Estimation of Baseline Pollutant Concentrations from 

Sites in the Metal-Bearing Subcategories .............. 12-10 

12.2.1.1 Estimation of Effluent Pollutant 

Concentrations for Untreated Streams ...... 12-10 

12.2.1.2 Estimation of Effluent Pollutant 

Concentrations for Treated Streams ........ 12-11 

12.2.1.3 Estimation of Commingled Effluent Pollutant 

Concentrations from Sites ............... 12-14 

12.2.2 Estimation of Baseline Pollutant Concentrations from 

Sites in the Oil-Bearing Subcategories ................ 12-15 

12.2.2.1 Estimation of Baseline Pollutant 

Concentrations from Sites in the Shipbuilding 

Dry Dock Subcategory .................. 12-15 

12.2.2.2 Estimation of Baseline Pollutant 

Concentrations from Sites in the Railroad 

Line Maintenance Subcategory ........... 12-16 

12.2.2.3 Estimation of Baseline Pollutant 

Concentrations from Sites in the Oily Wastes 

Subcategory .......................... 12-16 

12.2.3 Estimation of Model Site Baseline Loadings ........... 12-17 

12.2.4 Estimation of Industry-Wide Baseline Pollutant Loadings . 12-17 

viii 
Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

12.3 Estimation of Industry Option Pollutant Loadings .............. 12-18


12.3.1 Estimation of Industry Option Pollutant Loadings for Sites


in the Metal-Bearing Subcategories .................. 12-18


12.3.2 Estimation of Industry Option Pollutant Loadings for Sites


in the Shipbuilding Dry Dock Subcategory ............ 12-19


12.3.3 Estimation of Industry Option Pollutant Loadings for Sites


in the Railroad Line Maintenance Subcategory ......... 12-19


12.3.4 Estimation of Industry Option Pollutant Loadings for Sites


in the Oily Wastes Subcategory ..................... 12-19


12.4 Estimation of Pollutant Reductions .......................... 12-20


13.0	 NON-WATER QUALITY IMPACTS ................................... 13-1


13.1 Energy Requirements ...................................... 13-1


13.2 Air Emissions Impacts ..................................... 13-2


13.3 Solid Waste Generation .................................... 13-3


13.4 References .............................................. 13-4


14.0	 LONG-TERM AVERAGES AND EFFLUENT LIMITATIONS AND STANDARDS .... 14-1


14.1 General Metals Subcategory ................................ 14-1


14.2 Metal Finishing Job Shops Subcategory ....................... 14-2


14.3 Non-Chromium Anodizing Subcategory ....................... 14-2


14.4 Printed Wiring Board Subcategory ........................... 14-2


14.5 Steel Forming and Finishing Subcategory ...................... 14-2


14.6 Oily Wastes Subcategory ................................... 14-2


14.6.1 Best Practicable Control Technology (BPT) ............. 14-2


14.6.2 Best Conventional Pollutant Control Technology (BCT) ... 14-4


14.6.3 Best Available Technology Economically Achievable


(BAT) .......................................... 14-4


14.6.4 New Source Performance Standards (NSPS) ............ 14-4


14.6.5 Pretreatment Standards for Existing Sources (PSES) ...... 14-4


14.6.6 Pretreatment Standards for New Sources (PSNS) ........ 14-4


14.7 Railroad Line Maintenance Subcategory ....................... 14-5


14.8 Shipbuilding Dry Dock Subcategory .......................... 14-5


15.0 IMPLEMENTATION ............................................... 15-1


15.1	 Applicability of the MP&M Effluent Guidelines ................ 15-1


15.1.1 MP&M Industrial Sectors ........................... 15-2


15.1.2 Regulated Subcategory in the MP&M Effluent Guidelines . 15-3


15.1.3 Facilities Not Subject to the MP&M Effluent Guidelines .. 15-3


15.2 Compliance Dates ........................................ 15-9


15.3 Limits Development ....................................... 15-9


ix 
Table of Contents 

TABLE OF CONTENTS (Continued) 

Page 

15.4 Compliance Monitoring ................................... 15-12 

15.5 References ............................................. 15-13 

16.0 GLOSSARY OF TERMS ............................................ 16-1 

Appendix A - EXAMPLE NAICS AND SIC CODES FOR THE METAL PRODUCTS 

& MACHINERY FINAL EFFLUENT LIMITATIONS GUIDELINES 

AND STANDARDS 

Appendix B - ANALYTICAL METHODS AND BASELINE VALUES FOR THE 

METAL PRODUCTS AND MACHINERY INDUSTRY 

Appendix C - WASTEWATER CHARACTERISTICS 

Appendix D - POLLUTION PREVENTION AND WATER CONSERVATION 

PRACTICES 

Appendix E - MODIFIED DELTA-LOGNORMAL DISTRIBUTION 

x 
List of Tables 

LIST OF TABLES


Page 

1-1 Clarification of Coverage by Proposed MP&M Subcategory .............. 1-6


1-2 Technology Bases for Promulgated MP&M Limitations and Standards ...... 1-9


1-3	 Effluent Limitations Guidelines for the MP&M Point Source Category


(40 CFR 438) ................................................... 1-9


2-1 Summary of Regulatory Levels of Control ............................ 2-4


2-2 Summary of Metals Industry Effluent Guidelines ....................... 2-9


3-1 1989 and 1996 MP&M Survey Mailout Results ........................ 3-5


3-2 Summary of 1996 Detailed Survey Information by Question Number ...... 3-18


3-3 Number of Sites Visited Within Each Proposed Industrial Sector ......... 3-35


3-4 Number of Sites Sampled Within Each Proposed Industrial .............. 3-39


3-5 Metal Constituents Measured Under the MP&M Sampling Program ....... 3-42


3-6 Organic Constituents Measured Under the MP&M Sampling Program ..... 3-43


3-7 Additional Parameters Measured Under the MP&M Sampling Program .... 3-47


4-1 Wastewater-Discharging MP&M facilities by Sector .................... 4-5


4-2 Types of Proposed MP&M operations .............................. 4-13


4-3 List of MP&M Oily Operations .................................... 4-15


4-4 List of MP&M Metal-Bearing Operations ............................ 4-16


4-5	 Estimated Number of MP&M Facilities Discharging Process Wastewater


by Proposed MP&M Operation and Estimated Annual Discharge 


for Each Proposed MP&M Operation ............................... 4-36


5-1 Number of Process Water and Rinse Water Samples For Oily Operations .... 5-2


5-2 Process Water Pollutant Concentration Data for Oily Operations ........... 5-3


xi 
List of Tables 

LIST OF TABLES (Continued) 

Page 

5-3 Rinse Water Pollutant Concentration Data for Oily Operations ............ 5-8


5-4	 MP&M Pollutant Concentration Data for the Influent to Oily Wastewater


Treatment Systems .............................................. 5-14


6-1 Final Subcategories Evaluated in the Final Rule ........................ 6-2


6-2 Oily Operations as Defined by the Final Rule .......................... 6-3


6-3 Metal-Bearing Operations as Defined by the Final Rule .................. 6-4


6-4	 Percentage of Facilities Performing Proposed MP&M Operations


Using Multiple Metal Types by Subcategory ........................... 6-6


6-5	 Percentage of Facilities Performing Proposed MP&M Operations


by Subcategory Using Each Metal Type .............................. 6-8


7-1	 Pollutants Not Detected in Any Samples Collected During the


Phase I and Phase II MP&M Sampling Programs ....................... 7-4


7-2	 Pollutants Detected in Less Than Three Samples Collected


During the Phase I and Phase II MP&M Sampling Programs .............. 7-6


7-3	 Pollutants Detected at Average Concentrations of Less Than Five


Times the Minimum Level During the Phase I and Phase II MP&M


Sampling Programs .............................................. 7-7


7-4 Summary of Pollutants of Concern Information ........................ 7-8


7-5	 Pollutants Considered for Regulation for Direct Dischargers in the


Oily Wastes Subcategory ......................................... 7-15


8-1 MP&M Flow Reduction Technologies ............................... 8-3


8-2 MP&M In-Process Pollution Prevention Technologies .................. 8-10


8-3 MP&M Preliminary and End-of-Pipe Treatment Technologies ........... 8-32


9-1 Technology Options by Subcategory ................................ 9-37


9-2 Summary of Technology Bases for the Final Rule ..................... 9-38


xii 
List of Tables 

LIST OF TABLES (Continued) 

Page 

10-1 Oily Wastes Subcategory Oil/Water Separation ....................... 10-3


10-2 Unit Operations at Each Episode ................................... 10-5


10-3 Effluent Data Before Aggregation ................................. 10-10


10-4 Data After Aggregation (i.e., Daily Values) ......................... 10-11


10-5 Episode Long-Term Averages and Daily Variability Factors ............ 10-15


10-6 Option Long-Term Averages, Daily Variability Factors, and Limitations .. 10-17


10-7 Daily Maximum Limitations: Proposal, NODA, and Final Rule ......... 10-22


11-1 Incremental Capital and O&M Costs ................................ 11-2


11-2 Incremental Annualized Costs ..................................... 11-4


11-3 Information Contained in MSP1 ................................... 11-8


11-4 Information Contained in MSP2 .................................. 11-10


11-5 	 Treatment Technologies Considered Equivalent to the Option


Technologies ................................................. 11-13


11-6 Information Contained in MSP3 .................................. 11-15


11-7 Components of Total Capital Investment ........................... 11-19


11-8 Costs for Contracted Off-Site Treatment/Disposal of Various Waste Types 11-21


11-9 RS Means Building Construction Historical Cost Indexes .............. 11-22


11-10	 Monitoring Frequencies Used to Develop Part 438 Limitations Considered


for Metal-Bearing Subcategories ................................. 11-23


11-11	 Wastewater Treatment Technologies and Source Reduction and Recycling


Practices for Which EPA Developed Cost Modules ................... 11-26


11-12	 List of Unit Operations Feeding Each Treatment Unit or In-Process


Technology .................................................. 11-27


xiii 
List of Tables 

LIST OF TABLES (Continued) 

Page 

11-13 MP&M Equipment Cost Equations ................................ 11-43


11-14 Logic Used for Off-Site Treatment and Disposal Cost Estimates ......... 11-50


11-15 Treatment Technologies That Use Feed Systems ..................... 11-51


11-16 Treatment Dosage Information ................................... 11-52


12-1 POTW Removal Percentages For Each MP&M Pollutant of Concern .... 12-22


12-2	 Summary of Baseline Annual Pollutant Loadings Discharged by


Subcategory .................................................. 12-26


12-3	 Summary of Selected Option Annual Pollutant Loadings Discharged by


Subcategory .................................................. 12-28


12-4 Industry Pollutant Removals in Pounds (for Direct Dischargers) ......... 12-30


12-5 Industry Pollutant Removals in Pound-Equivalents ................... 12-31


13-1 Energy Usage for the Selected Technology Option ..................... 13-1


13-2 Waste Oil Removed by the Selected Option .......................... 13-3


14-1 BPT Effluent Limitations for the Oily Wastes Subcategory .............. 14-3


15-1	 Clarification of Coverage by MP&M Subcategory Evaluated for


the Final Rule .................................................. 15-5


15-2	 Effluent Limitations Guidelines for the MP&M Point Source Category


(40 CFR 438) ................................................. 15-11


16-1 Priority and Nonconventional Organic Pollutants Comprising the Total


Organics Parameter ............................................ 16-12


xiv 
List of Figures 

LIST OF FIGURES


Page 

3-1	 Percentage of 1989 and 1996 MP&M Surveys Returned and Percentage of


Survey Respondents Performing Proposed MP&M Operations ............ 3-6


3-2	 Number of Facilities Performing Proposed MP&M Operations Visited and


Sampled by Industrial Sector ...................................... 3-36


4-1	 Percentage of Wastewater-Discharging MP&M facilities and Percentage of


Annual Wastewater Discharge by Number of Employees ................. 4-3


4-2	 Estimated Number of Wastewater-Discharging MP&M facilities


by EPA Region .................................................. 4-4


4-3	 Percentage of Wastewater-Discharging MP&M facilities and Percentage of


Total Annual Discharge by Activity ................................. 4-7


4-4	 Percentage of Wastewater-Discharging MP&M facilities and Percentage of


Total Annual Discharge by Discharge Status .......................... 4-8


4-5	 Percentage of Wastewater-Discharging MP&M facilities and Percentage of


Total Annual MP&M Discharge by Flow Rate Range ................... 4-9


4-6	 Percentage of Screener Survey Respondents Using Each Zero Discharge 


Method ....................................................... 4-11


4-7	 Percentage of Wastewater-Discharging MP&M facilities by Number of


Metal Processed ................................................ 4-35


6-1 Percentage of Wastewater - Discharging Facilities Evaluated for the Final


Rule by Decade Built ........................................... 6-15


8-1 Countercurrent Cascade Rinsing .................................... 8-5


8-2 Machine Coolant Recycling System ................................ 8-14


8-3 Centrifugation and Recycling of Painting Water Curtains ............... 8-15


8-4 Electrodialysis Cell ............................................. 8-17


8-5 Membrane Filtration Unit ........................................ 8-21


xv 
List of Figures 

LIST OF FIGURES (Continued) 

Page 

8-6 Ion Exchange .................................................. 8-22


8-7 Chemical Reduction of Hexavalent Chrome .......................... 8-35


8-8 Cyanide Destruction Through Alkaline Chlorination ................... 8-37


8-9 Chemical Reduction / Precipitation of Chelated Metals ................. 8-40


8-10 Continuous Chemical Emulsion Breaking Unit with Coalescing Plates ..... 8-42


8-11a Disk Oil Skimming Unit ......................................... 8-44


8-11b Belt Oil Skimming Unit ......................................... 8-45


8-12 Dissolved Air Flotation Unit ...................................... 8-47


8-13 Continuous Chemical Precipitation System with Lamella Clarifier ........ 8-49


8-14 Effect of pH on Hydroxide and Sulfide Precipitation ................... 8-51


8-15 Center-Feed Rim Flow Clarifier ................................... 8-55


8-16 Multimedia Filtration System ..................................... 8-58


8-17 Gravity Thickening ............................................. 8-60


8-18 Plate-and-Frame Filter Press ...................................... 8-61


8-19 Rotary Vacuum Filter ............................................ 8-62


9-1	 End-of-Pipe Treatment Train for Options 1 and 2 Considered for the


Following Subcategories: General Metals, Metal Finishing Job Shops,


Non-Chromium Anodizing, Printed Wiring Board, and Steel Forming and


Finishing ..................................................... 9-39


9-2	 In-Process Water Use Reduction Technologies for Options 2 and 4


Considered for the Following Subcategories: General Metals, Metal


Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Board,


and Steel Forming and Finishing ................................... 9-40


xvi

List of Figures 

LIST OF FIGURES (Continued) 

Page 

9-3	 End-of-Pipe Treatment Train for Options 3 and 4 Considered for the


Following Subcategories: General Metals, Metal Finishing Job Shops,


Non-Chromium Anodizing, Printed Wiring Board, and Steel Forming


and Finishing .................................................. 9-41


9-4	 End-of-Pipe Treatment Train for Options 5 and 6 Considered for the


Following Subcategories: Oily Wastes and Railroad Line Maintenance ..... 9-42


9-5	 End-of-Pipe Treatment Train for Option 7 and 8 Considered for the


Following Subcategories: Oily Wastes, Railroad Line Maintenance,


Shipbuilding Dry Dock .......................................... 9-42


9-6	 End-of-Pipe Treatment Train for Options 9 and 10 Considered for


the Following Subcategories: Railroad Line Maintenance and Shipbuilding


Dry Dock ..................................................... 9-43


11-1	 Relationship Between In-Process and End-of-Pipe Technologies and 


Practices ..................................................... 11-62


11-2 Components of Total Capital Investment ........................... 11-63


11-3	 Logic Used to Apply End-of-Pipe Technologies and Practices for the


Following Subcategories: General Metals, Metal Finishing Job Shops,


Non-Chromium Anodizing, Printed Wiring Board, and Steel Forming


and Finishing ................................................. 11-64


11-4	 Logic Used to Apply End-of-Pipe Technologies and Practices for the


Following Subcategories30: Oily Wastes, Railroad Line Maintenance,


and Shipbuilding Dry Dock ...................................... 11-65


11-5	 Example Treatment Facility for General Metals Subcategory Direct


Discharger ................................................... 11-66


15-1 MP&M Permitting Process Flow Chart ............................. 15-10


xvii 
1.0 - Summary and Scope of the Regulation 

1.0 SUMMARY AND SCOPE OF THE REGULATION 

This section presents a brief overview of the Metal Products and Machinery 

(MP&M) Point Source Category, discusses the applicability of the MP&M effluent limitations 

guidelines and standards for the category, and presents the applicability interface between the 

final rule and other regulations for the metals industry. This section also briefly summarizes the 

final rule and describes the Agency’s efforts to protect confidential business information. This 

section is organized as follows: 

& Section 1.1 - Overview of the MP&M Point Source Category; 

& Section 1.2 - Overlap with other effluent guidelines; 

& Section 1.3 - Summary of applicability; 

& Section 1.4 - Promulgated effluent limitations guidelines and standards; 

and 

& Section 1.5 - Protection of confidential business information. 

1.1 Overview of the MP&M Point Source Category 

The MP&M Point Source Category includes facilities that discharge wastewater 

from processing metal parts, metal products, and machinery. This processing can be described 

by two types of activities: manufacturing and rebuilding/maintenance. Manufacturing is the 

series of unit operations necessary to produce metal products and is generally performed in a 

production environment. Rebuilding/maintenance is the series of unit operations necessary to 

disassemble used metal products into components, replace the components or subassemblies or 

restore them to original function, and reassemble the metal product. Rebuilding and maintenance 

operations are intended to keep metal products in operating condition and can be performed in 

either a production or a nonproduction environment. The MP&M Point Source Category 

encompasses manufacturing, rebuilding, or maintenance of metal parts, products, or machines for 

use in the following industrial sectors: 

& Aerospace;


& Aircraft;


& Bus and Truck; 


& Electronic Equipment;


& Hardware;


& Household Equipment;


& Instruments;


& Mobile Industrial Equipment;


& Motor Vehicle;


& Office Machine;


1-1

1.0 - Summary and Scope of the Regulation 

& Ordnance; 


& Precious Metals and Jewelry;


& Railroad;


& Ships and Boats;


& Stationary Industrial Equipment; and


& Miscellaneous Metal Products.


EPA also evaluated manufacturing, rebuilding, or maintenance of metal parts, 

products, or machines used in two other industrial sectors (Job Shops and Printed Wiring Board) 

but has decided not to regulate them as part of the final rule. 

These sectors considered by EPA for regulation manufacture, maintain, and 

rebuild metal products under more than 200 different Standard Industrial Classification (SIC) 

codes. Appendix A includes a list of example SIC codes and North American Industrial 

Classification System (NAICS) codes that apply to the above industrial sectors. EPA is not 

revising limitations and standards for three proposed industrial sectors (i.e., job shops, printed 

wiring board, and steel forming and finishing). 

The final rule does not apply to maintenance or repair of metal parts, products, or 

machines that takes place only as ancillary activities at facilities not included in the 16 MP&M 

industrial sectors. EPA estimates that these ancillary repair and maintenance activities would 

typically discharge de minimis quantities of process wastewater. For example, wastewater 

discharges from repair of metal parts at oil and gas extraction facilities (40 CFR 435) are not 

subject to the final rule. The Agency has determined that permit writers are establishing limits 

using best professional judgment (BPJ) to regulate wastewater discharges from ancillary waste 

streams for direct dischargers (see 66 FR 433). 

Facilities in any one of the 16 industrial sectors in the MP&M Point Source 

Category are subject to the final rule only if they directly discharge process wastewater resulting 

from one or more of the following “oily operations:” 

& Abrasive Blasting;


& Adhesive Bonding;


& Alkaline Cleaning for Oil Removal;


& Alkaline Treatment Without Cyanide;


& Aqueous Degreasing;


& Assembly/Disassembly;


& Burnishing;


& Calibration;


& Corrosion Preventative Coating (as specified at 40 CFR 438.2(c) and


Appendix C of Part 438); 

& Electrical Discharge Machining; 

& Floor Cleaning (in Process Area); 

& Grinding; 

1-2

1.0 - Summary and Scope of the Regulation 

& Heat Treating;


& Impact Deformation;


& Iron Phosphate Conversion Coating;


& Machining;


& Painting-Spray or Brush (Including Water Curtains);


& Polishing;


& Pressure Deformation;


& Solvent Degreasing;


& Steam Cleaning;


& Testing (e.g., hydrostatic, dye penetrant, ultrasonic, magnetic flux);


& Thermal Cutting;


& Tumbling/Barrel Finishing/Mass Finishing/Vibratory Finishing;


& Washing (Finished Products);


& Welding;


& Wet Air Pollution Control for Organic Constituents; and


& Suboperations within the operations listed above (see Section 5.0).


These operations are defined in Appendix B to 40 CFR 438 and also in Section 4.0. 

In addition, the final rule covers process wastewater resulting from associated 

rinses that remove materials that the processes listed above deposit on the surface of the work 

piece. The final rule does not apply to direct discharges of wastewaters that are otherwise 

covered by other effluent limitations guidelines. 

The final rule also covers direct discharges of process wastewater generated from 

oily operations related to maintenance and repair of metal products, parts, and machinery at 

military installations (i.e., federal facilities) as well as facilities owned or operated by state or 

local governments. For example, the final rule covers direct discharges of process wastewater 

generated from oily operations related to maintenance and repair of aircraft, cars, trucks, buses, 

tanks (or other armor personnel carriers), and industrial equipment. These operations are 

commonly performed at military installations and state or local government maintenance 

facilities. However, the final rule does not apply to wastewater discharges introduced into a 

federally owned and operated Treatment Works Treating Domestic Sewage (TWTDS), as 

defined at 40 CFR 122.2. 

The MP&M Point Source Category evaluated for the final rule encompasses more 

than 41,000 facilities that manufacture, rebuild, or maintain metal parts, products, or machines 

for use in the 16 MP&M industrial sectors. Approximately 29,000 of these facilities annually 

discharge 5.02 billion gallons of process wastewater. Of the facilities discharging process 

wastewater, EPA estimates that 91.6 percent are indirect dischargers, 8.4 percent are direct 

dischargers, and 0.1 percent discharge both directly and indirectly. The Agency estimates that 

the remaining facilities (an estimated 12,000) fall into one of three categories: 

1-3

1.0 - Summary and Scope of the Regulation 

& Zero discharge. A zero-discharging facility does not discharge pollutants 

to waters of the United States or to a POTW. Included in this definition 

are discharge or disposal of pollutants by way of evaporation, deep-well 

injection, off-site transfer to a treatment facility, and land application. 

& Non-water-using. A non-water-using facility does not use process 

wastewater (i.e., water that comes into direct contact with or results from 

the production or use of any raw material, intermediate product, finished 

product, by-product, or waste product) at its oily operation. 

& Contract haulers. Contract hauling is the removal of any waste stream 

from a facility by a company authorized to transport and dispose of the 

waste, excluding discharges to sewers or surface waters. 

The MP&M final rule does not regulate indirect dischargers and discharges to 

federally owned and operated TWTDS. There are approximately 2,400 direct dischargers 

regulated by the MP&M final rule. 

MP&M sites evaluated for the final rule perform a wide variety of process unit 

operations on metal parts, products, or machines. In general, MP&M unit operations can be 

characterized as belonging to one of the following types of unit operations: 

& Assembly/disassembly operations; 

& Metal shaping operations; 

& Organic chemical deposition operations; 

& Surface finishing operations; and 

& Surface preparation operations. 

EPA also evaluated the following types of unit operations but has decided not to 

regulate them as part of the final rule: 

& Dry dock operations; and 

& Metal deposition operations. 

Specifically, EPA decided not to regulate “metal-bearing operations” as defined in 40 CFR 

438.2(d) and Appendix C to Part 438. The list of unit operations not regulated by the final rule is 

also given in Section 4.0. 

At a given MP&M facility, the specific unit operations performed and the 

sequence of those operations depend on many factors, including the activity (i.e., manufacturing, 

rebuilding, or maintenance), industrial sector, and type of product processed. The extent to 

which a facility uses process water for these unit operations also varies from site to site. 

1-4

1.0 - Summary and Scope of the Regulation 

The approximately 2,400 sites regulated by the MP&M final rule discharge 

approximately 267 million gallons of process wastewater per year. This wastewater typically 

contains total suspended solids, oil and grease, and organic pollutants. MP&M wastewater may 

also contain some metals (e.g., zinc, tin, aluminum), often in suspended or particulate phase. 

1.2 Overlap with Other Effluent Guidelines 

EPA has previously established effluent limitations guidelines and standards for 

13 industries that may perform unit operations or process parts that are sometimes found at 

MP&M sites. These effluent guidelines are: 

& Electroplating (40 CFR 413);


& Iron and Steel Manufacturing (40 CFR 420);


& Nonferrous Metals Manufacturing (40 CFR 421);


& Ferroalloy Manufacturing (40 CFR 424);


& Metal Finishing (40 CFR 433);


& Battery Manufacturing (40 CFR 461);


& Metal Molding and Casting (40 CFR 464);


& Coil Coating (40 CFR 465);


& Porcelain Enameling (40 CFR 466);


& Aluminum Forming (40 CFR 467);


& Copper Forming (40 CFR 468);


& Electrical and Electronic Components (40 CFR 469); and


& Nonferrous Metals Forming & Metal Powders (40 CFR 471).


In 1986, the Agency reviewed coverage of these regulations and identified a 

significant number of metals-processing facilities discharging wastewater that these 13 

regulations did not cover. Based on this review, EPA performed a more detailed analysis of 

these unregulated sites and identified the discharge of significant amounts of pollutants (see 

Section 1.1 of the rulemaking record, DCN M432). This analysis resulted in the decision to 

develop national limitations guidelines and standards for the “Metal Products and Machinery” 

(MP&M) Point Source Category (see Section 2.2.5). 

Table 1-1 summarizes the coverage of industrial operations by each MP&M 

subcategory for which EPA proposed regulations. Additionally, the MP&M final rule does not 

apply to process wastewaters from metal-bearing operations (as defined at §438.2(d) and 

Appendix C of Part 438) or process wastewaters that are subject to the limitations and standards 

of other effluent limitations guidelines (e.g., Metal Finishing (40 CFR 433) or Iron and Steel 

Manufacturing (40 CFR 420)). 

1-5

1.0 - Summary and Scope of the Regulation 

Table 1-1 

Clarification of Coverage by Proposed MP&M Subcategory 

Proposed Subcategory 

Continue to 

Cover Under 

40 CFR 413 

(Electroplating) 

Continue to 

Cover Under 

40 CFR 433 

(Metal Finishing) 

Cover Under 

40 CFR 438 

(Metal Products & 

Machinery) 

General Metals (Including 

Continuous Electroplaters) 

Existing indirect 

dischargers covered by 

Part 413. 

New and existing 

direct and indirect 

dischargers covered 

by Part 433. 

None 

Metal Finishing Job Shops Existing indirect 

dischargers covered by 

Part 413. 

New and existing 

direct and indirect 

dischargers covered 

by Part 433. 

Non-Chromium Anodizing Existing indirect 

dischargers covered by 

Part 413. 

New and existing 

direct and indirect 

dischargers covered 

by Part 433. 

Printed Wiring Board 

(Printed Circuit Board) 

Existing indirect 

dischargers covered by 

Part 413. 

New and existing 

direct and indirect 

dischargers covered 

by Part 433. 

Steel Forming and Finishinga NA NA 

Oily Wastes NA NA 

Railroad Line Maintenance NA NA 

None 

None 

None 

None 

All new and existing 

direct dischargers 

(see 438.10). 

None 

Shipbuilding Dry Dock NA NA None 

NA - Not applicable. a

These facilities will remain subject to 40 CFR 420. 

1-6

1.0 - Summary and Scope of the Regulation 

1.3 Summary of Applicability 

The MP&M effluent limitations guidelines and standards regulate process 

wastewater from oily operations at existing or new direct dischargers engaged in manufacturing, 

rebuilding, or maintenance of metal parts, products, or machines used in any of the 16 industrial 

sectors listed in Section 1.1. The guidelines and standards do not apply to wastewater from oily 

operations in certain circumstances (e.g., if they are subject to other national effluent limitations 

or standards). The MP&M regulation does not regulate any of the other subcategories for which 

it proposed regulations. These subcategories are the General Metals, Metal Finishing Job Shops, 

Non-Chromium Anodizing, Printed Wiring Board, Steel Forming and Finishing, Railroad Line 

Maintenance, and Shipbuilding Dry Dock. Process wastewater is defined in §438.2. 

EPA defines process wastewater for the final rule to include wastewater 

discharges from oily operations for the manufacturing, rebuilding, or maintenance of metal parts, 

products, or machinery for use in any of the 16 MP&M industrial sectors and wastewater from air 

pollution control devices. 

EPA notes that direct discharges resulting from the washing of cars, aircraft, or 

other vehicles, when performed as a prepatory step prior to one or more successive 

manufacturing, rebuilding, or maintenance operations, are subject to the MP&M rule. 

Nonprocess wastewater discharges are not subject to the final rule. Nonprocess 

wastewater means sanitary wastewater, noncontact cooling water, water from laundering, and 

noncontact stormwater. Nonprocess wastewater for this part also includes wastewater discharges 

from nonindustrial sources such as residential housing, schools, churches, recreational parks, 

shopping centers as well as wastewater discharges from gas stations, utility plants, and hospitals. 

In addition to nonprocess wastewater, the final rule does not apply to wastewater 

generated from: (1) gravure cylinder and metallic platemaking conducted within or for printing 

and publishing facilities; (2) the washing of cars, aircraft or other vehicles when it is performed 

only for aesthetic/cosmetic purposes; (3) MP&M operations at gasoline stations (SIC Code 5541) 

or vehicle rental facilities (SIC Codes 7514 or 7519); or (4) unit operations performed by drum 

reconditioners/refurbishers to prepare metal drums for reuse. 

As noted, EPA is also not promulgating limitations and standards for facilities in 

the proposed Shipbuilding Dry Dock Subcategory. The final rule does not cover wastewater 

generated on-board ships and boats when they are afloat (that is, not in dry docks or similar 

structures), flooding water, and dry dock ballast water (see 66 FR 445). For U.S. military ships, 

EPA is in the process of establishing standards to regulate discharges of wastewater generated 

on-board these ships when they are in U.S. waters and are afloat under the Uniform National 

Discharge Standards (UNDS) pursuant to section 312(n) of the Clean Water Act (CWA) (see 64 

FR 25125, May 10, 1999). 

1-7

1.0 - Summary and Scope of the Regulation 

Finally, as previously stated, the final rule does not apply to maintenance or repair 

of metal parts, products, or machines that takes place only as ancillary activities at facilities not 

included in the 16 MP&M industrial sectors. 

See Section 15.0 for a more detailed discussion regarding applicability. 

1.4 Promulgated Effluent Limitations Guidelines and Standards 

EPA proposed effluent limitations and standards for eight subcategories. 

However, for reasons discussed in Section 9.0 and Section VI of the preamble to the final rule, 

the final rule establishes effluent limitations guidelines and standards for new and existing direct 

dischargers in one subcategory: Oily Wastes. 

EPA may divide a point source category (e.g., MP&M) into groupings called 

“subcategories” to provide a method for addressing variations between products, raw materials, 

processes, and other factors that result in distinctly different effluent characteristics. Regulation 

of a category using subcategories allows each subcategory to have a uniform set of effluent 

limitations that take into account technological achievability and economic impacts unique to 

that subcategory. Grouping similar facilities into subcategories increases the likelihood that the 

regulations are practicable, and diminishes the need to address variations between facilities 

through a variance process. The CWA requires EPA, in developing effluent limitations 

guidelines and pretreatment standards, to consider a number of different subcategorization 

factors. (See Section 6.0 for a list of the factors considered for the final MP&M rule and a 

detailed discussion of subcategorization.) 

EPA is promulgating concentration-based limits and standards for direct 

dischargers for the Oily Wastes Subcategory. However, the CWA authorizes permit writers to 

decide when it is most appropriate to implement mass-based limits. Guidance for setting limits 

is included in Section 15.0. 

Table 1-2 summarizes the regulatory levels of control and selected technology 

bases EPA used in promulgating the limitations and standards presented in Table 1-3, Section 

14.0, and 40 CFR 438, Subpart A (Oily Wastes Subcategory). Section 15.0 provides guidance to 

permit writers. 

1-8

1.0 - Summary and Scope of the Regulation 

Table 1-2


Technology Bases for Promulgated MP&M Limitations and Standards


Subcategory Regulatory Level Selected Technology Option

Oily Wastes BPT/BCT/NSPS Pollution prevention; chemical emulsion breaking and 

oil/water separation (Option 6). See Section 9.7. 

BAT No limitations established under Part 438. 

PSES/PSNS No standards established under Part 438. 

Table 1-3 

Effluent Limitations Guidelines for the MP&M Point Source Category 

(40 CFR 438) 

BPT/BCT/NSPS - Oily Wastes Subcategory 

Regulated Parameter 

Maximum Daily 

mg/L (ppm) 

Total Suspended Solids (TSS) 62 

Oil and Grease (as HEM) 46 

pH a 

a

Discharges must remain within the pH range 6 to 9. 

Protection of Confidential Business Information 

Whenever EPA is required to develop effluent limitations, pretreatment standards, 

or other standards, Section 308(a) of the CWA authorizes the Agency to require owners or 

operators of point sources to provide certain information. Various statutes under which EPA 

operates contain special provisions concerning the entitlement to confidential treatment of certain 

business information (CBI). In compliance with these statutes and EPA’s implementing 

regulations, the Agency has withheld CBI from the public record in the Water Docket, but retains 

CBI in the nonpublic version of the rulemaking record. In addition, the Agency has withheld 

from disclosure some data not claimed as CBI because the release of these data could indirectly 

reveal CBI. Furthermore, EPA has aggregated certain data in the public record, masked facility 

identities, or used other strategies to prevent the disclosure of CBI. The Agency’s approach to 

CBI protection ensures that the data in the public record both explain the basis for the final rule 

and provide the opportunity for public comment, without compromising data confidentiality. 

1-9


1.5 
2.0 - Background 

2.0 BACKGROUND 

This section presents background information supporting the development of 

effluent limitations guidelines and standards for the Metal Products and Machinery (MP&M) 

Point Source Category. Section 2.1 presents the legal authority to regulate the MP&M industry. 

Section 2.2 discusses the Clean Water Act, Pollution Prevention Act, Regulatory Flexibility Act 

(as amended by the Small Business Regulatory Enforcement Fairness Act of 1996), and prior 

regulation of the metals industry. 

2.1 Legal Authority 

EPA is promulgating these regulations under the authority of Sections 301, 304, 

306, 307, 308, 402, and 501 of the Clean Water Act, 33 U.S.C.1311, 1314, 1316, 1317, 1318, 

1342, and 1361 and under authority of the Pollution Prevention Act of 1990 (PPA), 42 U.S.C. 

13101 et seq., Public Law 101-508, November 5, 1990. 

2.2 Regulatory Background 

2.2.1 Clean Water Act 

Congress adopted the Clean Water Act (CWA) to ‘‘restore and maintain the 

chemical, physical, and biological integrity of the Nation’s waters’’ (Section 101(a), 33 U.S.C. 

1251(a)). To achieve this goal, the CWA prohibits the discharge of pollutants into navigable 

waters except in compliance with the statute. The CWA confronts the problem of water pollution 

on a number of different fronts. Its primary reliance, however, is on establishing restrictions on 

the types and amounts of pollutants discharged from various industrial, commercial, and public 

sources of wastewater. 

Congress recognized that regulating only those sources that discharge effluent 

directly into the nation’s waters would not be sufficient to achieve the CWA’s goals. 

Consequently, the CWA requires EPA to promulgate nationally applicable pretreatment 

standards that restrict pollutant discharges for those who discharge wastewater indirectly through 

sewers flowing to publicly owned treatment works (POTWs) (Sections 307(b) and (c), 33 U.S.C. 

1317(b) and (c)). National pretreatment standards are established for those pollutants in 

wastewater from indirect dischargers that may pass through or interfere with POTW operations. 

Generally, pretreatment standards are designed to ensure that wastewater from direct and indirect 

industrial dischargers are subject to similar levels of treatment. In addition, EPA requires 

POTWs to implement local pretreatment limits applicable to their industrial indirect dischargers 

to satisfy any local requirements (40 CFR 403.5). 

Direct dischargers must comply with effluent limitations in National Pollutant 

Discharge Elimination System (‘‘NPDES’’) permits; indirect dischargers must comply with 

pretreatment standards. EPA establishes these limitations and standards by regulation for 

2-1

2.0 - Background 

categories of industrial dischargers and bases them on the degree of control that can be achieved 

using various levels of pollution control technology. 

1.	 Best Practicable Control Technology Currently Available (BPT) 

(Section 304(b)(1) of the CWA) 

BPT effluent limitations guidelines are applicable to direct dischargers 

(i.e., sites that discharge wastewater to surface water). BPT effluent 

limitations guidelines are generally based on the average of the best 

existing performance by facilities of various sizes, ages, unit processes or 

other common characteristics within the category or subcategory for 

control of conventional, priority, and nonconventional pollutants. Section 

304(a)(4) designates the following as conventional pollutants: 

biochemical oxygen demand (BOD5), total suspended solids (TSS), fecal 

coliform, pH, and any additional pollutants defined by the Administrator 

as conventional. The Administrator designated oil and grease as an 

additional conventional pollutant on July 30, 1979 (44 FR 44501). EPA 

has identified 65 pollutants and classes of pollutants as toxic pollutants, of 

which 126 specific substances have been designated priority toxic 

pollutants. See Appendix A to Part 403 (reprinted after 40 CFR 423.17). 

All other pollutants are considered to be nonconventional. 

In establishing BPT effluent limitations guidelines, EPA first considers the 

total cost of applying the control technology in relation to the effluent 

reduction benefits. The Agency also considers the age of the equipment 

and facilities involved, the processes employed and any required process 

changes, engineering aspects of the control technologies, non-water quality 

environmental impacts (including energy requirements), and such other 

factors as the EPA Administrator deems appropriate (CWA 304(b)(1)(B)). 

Traditionally, EPA establishes BPT effluent limitations based on the 

average of the best performances of facilities within the industry of various 

ages, sizes, processes or other common characteristics. Where existing 

performance is uniformly inadequate, EPA may require higher levels of 

control than are currently in place in an industrial category if the Agency 

determines that the technology can be practically applied. 

2.	 Best Conventional Pollutant Control Technology (BCT) 

(Section 304(b)(4) of the CWA) 

The 1977 amendments to the CWA established BCT for discharges of 

conventional pollutants from existing industrial point sources. BCT 

effluent limitations guidelines are applicable to direct discharging sites. In 

addition to other factors specified in Section 304(b)(4)(B), the CWA 

requires that EPA establish BCT limitations after consideration of a two2-2

2.0 - Background 

part "cost-reasonableness" test. EPA explained its methodology for the 

development of BCT limitations in 1986 (51 FR 24974; July 9, 1986). 

3.	 Best Available Technology Economically Achievable (BAT) 

(Sections 304(b)(2) of the CWA) 

BAT effluent limitations guidelines are applicable to direct discharging 

sites. In general, BAT effluent limitations guidelines represent the best 

available economically achievable performance of plants in the industrial 

subcategory or category. The CWA establishes BAT as the principal 

national means of controlling the direct discharge of priority pollutants and 

nonconventional pollutants to waters of the United States. The factors 

considered in assessing BAT include the cost of achieving BAT effluent 

reductions, the age of equipment and facilities involved, the processes 

employed, potential process changes, non-water quality environmental 

impacts (including energy requirements), and such factors as the 

Administrator deems appropriate. The Agency retains considerable 

discretion in assigning the weight to be accorded to these factors. As with 

BPT, where existing performance is uniformly inadequate, EPA may base 

BAT upon technology transferred from a different subcategory within an 

industry or from another industrial category. In addition, BAT may 

include process changes or internal controls, even when these technologies 

are not common industry practice. 

4.	 New Source Performance Standards (NSPS) 

(Section 306 of the CWA) 

NSPS are applicable to new direct discharging sites and are based on the 

best available demonstrated treatment technology. New facilities have the 

opportunity to install the best and most efficient production processes and 

wastewater treatment technologies. As a result, NSPS should represent the 

greatest degree of effluent reduction attainable through the application of 

the best available demonstrated control technology for all pollutants (i.e., 

conventional, nonconventional, and priority pollutants). In establishing 

NSPS, the CWA directs EPA to take into consideration the cost of 

achieving the effluent pollutant reduction and any non-water quality 

environmental impacts (including energy requirements). 

5.	 Pretreatment Standards for Existing Sources (PSES) 

(Section 307(b) of the CWA) 

PSES are applicable to indirect discharging sites (i.e., sites that discharge 

to a POTW). The CWA requires PSES for pollutants that pass through, 

interfere with, or are otherwise incompatible with POTW treatment 

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2.0 - Background 

processes or sludge disposal methods. The CWA specifies that 

pretreatment standards are to be technology-based and analogous to the 

BAT effluent limitations guidelines. 

The General Pretreatment Standards, which set forth the framework for 

implementing categorical pretreatment standards, are found at 40 CFR 

403. 

6.	 Pretreatment Standards for New Sources (PSNS) 

(Section 307(c) of the CWA) 

PSNS are applicable to new indirect discharging sites. Like PSES, PSNS 

are designed to prevent the discharges of pollutants that pass through, 

interfere with, or are otherwise incompatible with the operation of 

POTWs. PSNS are to be issued at the same time as NSPS. New indirect 

dischargers have the opportunity to incorporate into their plants the best 

available demonstrated technologies. The Agency considers the same 

factors in promulgating PSNS that it considers in promulgating NSPS. 

The following table summarizes these regulatory levels of control and the pollutants controlled. 

Table 2-1 

Summary of Regulatory Levels of Control 

Type of Sites Regulated BPT BCT BAT NSPS PSES PSNS 

Existing Direct Dischargers 

New Direct Dischargers 

Existing Indirect Dischargers 

New Indirect Dischargers 

X X X 

X 

X 

X 

Pollutants Regulated BPT BCT BAT NSPS PSES PSNS 

Priority Pollutants 

Nonconventional Pollutants 

Conventional Pollutants 

X 

X 

X X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

Source: Clean Water Act. 

EPA typically does not establish pretreatment standards for conventional 

pollutants (e.g., BOD5, TSS, oil and grease) since POTWs are designed to treat these pollutants, 

but EPA has exercised its authority to establish categorical pretreatment standards for 

conventional pollutants as surrogates for toxic or nonconventional pollutants or to prevent 

interference. For example, EPA established categorical pretreatment standards for new and 

existing sources with a one-day maximum concentration of 100 mg/L oil and grease in the 

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2.0 - Background 

Petroleum Refining Point Source Category (40 CFR 419) to "minimize the possibility of slug 

loadings of oil and grease being discharged to POTWs" (see Section 24.4 of the rulemaking 

record, DCN 17949). 

2.2.2 Section 304(m) Requirements 

Section 304(m) of the CWA, added by the Water Quality Act of 1987, requires 

EPA to establish schedules for: (1) reviewing and revising existing effluent limitations guidelines 

and standards; and (2) promulgating new effluent guidelines. On January 2, 1990, EPA published 

an Effluent Guidelines Plan (see 55 FR 80), in which schedules were established for developing 

new and revised effluent guidelines for several industry categories, including the metal products 

and machinery industry. 

Natural Resources Defense Council, Inc. (NRDC) and Public Citizen, Inc. 

challenged the Effluent Guidelines Plan in a suit filed in the U.S. District Court for the District of 

Columbia, (NRDC et al v. Browner, Civ. No. 89-2980). On January 31, 1992, the Court entered a 

consent decree (the "304(m) Decree"), which establishes schedules for, among other things, 

EPA's proposal and promulgation of effluent guidelines for a number of point source categories. 

The consent decree, as amended, requires EPA to take final action on the Metal Products and 

Machinery effluent guidelines by February 14, 2003. 

2.2.3 Pollution Prevention Act 

The Pollution Prevention Act of 1990 (PPA) (42 U.S.C. 13101 et seq., Public Law 

101-508, November 5, 1990) "declares it to be the national policy of the United States that 

pollution should be prevented or reduced whenever feasible; pollution that cannot be prevented 

should be recycled in an environmentally safe manner, whenever feasible; pollution that cannot 

be prevented or recycled should be treated in an environmentally safe manner whenever feasible; 

and disposal or release into the environment should be employed only as a last resort..." (Sec. 

6602; 42 U.S.C. 13101 (b)). In short, preventing pollution before it is created is preferable to 

trying to manage, treat or dispose of it after it is created. The PPA directs the Agency to, among 

other things, "review regulations of the Agency prior and subsequent to their proposal to 

determine their effect on source reduction" (Sec. 6604; 42 U.S.C. 13103(b)(2)). EPA reviewed 

this effluent guideline for its incorporation of pollution prevention. 

According to the PPA, source reduction reduces the generation and release of 

hazardous substances, pollutants, wastes, contaminants, or residuals at the source, usually within 

a process. The term source reduction "include[s] equipment or technology modifications, process 

or procedure modifications, reformulation or redesign of products, substitution of raw materials, 

and improvements in housekeeping, maintenance, training or inventory control. The term ‘source 

reduction' does not include any practice which alters the physical, chemical, or biological 

characteristics or the volume of a hazardous substance, pollutant, or contaminant through a 

process or activity which itself is not integral to or necessary for the production of a product or 

the providing of a service." 42 U.S.C. 13102(5). In effect, source reduction means reducing the 

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2.0 - Background 

amount of a pollutant that enters a waste stream or that is otherwise released into the environment 

prior to out-of-process recycling, treatment, or disposal. 

EPA gathered information on pollution prevention practices used by the MP&M 

industry from site visits, survey responses, and other references. Typical pollution prevention 

practices include reducing water use, extending the life of process bath constituents, or adding 

recycle or reuse technologies. See Section 8.0 for a detailed discussion of these practices. EPA 

supports pollution prevention technology by including pollution prevention in its technology 

bases for the final MP&M effluent limitations and new source performance standards. This 

includes water conservation and reuse of lubricants and solvents. Technology options 

considered, as well as selected, as the basis for the MP&M effluent limitations guidelines and 

standards include pollution prevention practices and are discussed in Section 9.0. 

2.2.4	 Regulatory Flexibility Act (RFA) as Amended by the Small Business 

Regulatory Enforcement Fairness Act of 1996 (SBREFA) 

The RFA generally requires an agency to prepare a regulatory flexibility analysis 

of any rule subject to notice and comment rulemaking requirements under the Administrative 

Procedure Act or any other statute unless the agency certifies that the rule will not have a 

significant economic impact on a substantial number of small entities. Small entities include 

small businesses, small organizations, and small governmental jurisdictions. 

For assessing the impacts of the final rule on small entities, a small entity is 

defined as: (1) a small business according to the Regulations of the Small Business 

Administration (SBA) at 13 CFR 121.201, which define small businesses for Standard Industrial 

Classification (SIC) codes; (2) a small governmental jurisdiction that is a government of a city, 

county, town, school district or special district with a population of less than 50,000; and (3) a 

small organization that is any not-for-profit enterprise that is independently owned and operated 

and is not dominant in its field. 

In accordance with Section 603 of the RFA, EPA prepared an initial regulatory 

flexibility analysis (IRFA) for the proposed rule and convened a Small Business Advocacy 

Review Panel to obtain advice and recommendations of representatives of the regulated small 

entities in accordance with Section 609(b) of the RFA (see 66 FR 519). The results of IRFA are 

provided in Chapter 10 of the Economic, Environmental, and Benefits Analysis (EEBA) (EPA821-B-03-002). The January 2001 proposed rule (see 66 FR 523) presents a summary of the 

Panel’s recommendations and the full Panel Report (see Section 11.2, DCN 16127) presents a 

detailed discussion of the Panel’s advice and recommendations. 

A regulatory flexibility analysis addresses: 

� The need for, objectives of, and legal basis for a rule. 

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2.0 - Background 

� A description of, and where feasible, an estimate of the number of small 

entities to which a rule would apply. 

� The projected reporting, recordkeeping, and other compliance requirements 

of a rule, including an estimate of the classes of small entities that would 

be subject to a rule and the types of professional skills necessary for 

preparation of the report or record. 

� An identification, where practicable, of all relevant federal rules that may 

duplicate, overlap, or conflict with a rule. 

� A description of any significant regulatory alternatives to a rule that 

accomplish the stated objectives of applicable statutes and that minimize 

any significant economic impact of a rule on small entities. Consistent 

with the stated objectives of the CWA, the analysis discusses significant 

alternatives such as: 

- Establishing differing compliance or reporting requirements or 

timetables that take into account the resources available to small 

entities. 

- Clarifying, consolidating, or simplifying compliance and reporting 

requirements under the rule for such small entities. 

- Using performance rather than design standards. 

- Excluding from coverage of a rule, or any part thereof, such small 

entities. Based on the regulatory flexibility analysis and other 

factors, EPA considered an exclusion to eliminate disproportionate 

impacts on small businesses, which reduced the number of small 

businesses that would be affected by a rule. 

The Small Business Advocacy Review Panel comprised representatives from three 

federal agencies: EPA, the Small Business Administration, and the Office of Management and 

Budget. The Panel reviewed materials EPA prepared in connection with the proposed rule IRFA, 

and collected the advice and recommendations of small entity representatives. For the Small 

Business Advocacy Review Panel, the small entity representatives included nine small MP&M 

facility owner/operators, one small municipality, and these six trade associations representing 

different sectors of the industry: 

� National Association of Metal Finishers (NAMF)/Association of 

Electroplaters and Surface Finishers (AESF)/MP&M Coalition; 

� Association Connecting Electronics Industries (also known as IPC); 

2-7

2.0 - Background 

� Porcelain Enamel Institute; 

� American Short Line Railroad Association (ASLRA); 

� Electronics Industry Association (EIA); and 

� American Wire Producers Association (AWPA). 

The Panel provided background information and analysis to the small entity 

representatives and conducted meetings with the representatives. The Panel asked the small entity 

representatives to submit written comment on the MP&M proposed rule in relation to the 

elements of the proposal IRFA. The Panel carefully considered these comments when developing 

their recommendations. The Panel’s report summarizes their outreach to small entities and the 

comments submitted by the small entity representatives. The Panel’s report also presented their 

findings on issues related to the elements of the proposal IRFA and recommendations regarding 

the rulemaking. Based on this input, EPA made several changes to the January 2001 proposal 

that reduced the number of small entities regulated and the level of impact to small entities that 

remain within the scope of the regulation. 

In the final rule, EPA excluded direct dischargers in seven of eight proposed 

subcategories and indirect dischargers in all eight proposed subcategories. Consequently, EPA 

excluded most small entities from additional regulation (see Section VI of the MP&M preamble 

to the final rule and Chapter 10 of the EEBA). To assess the potential economic impact of the 

final rule on small entities regulated by the final rule, EPA drew on: (1) a comparison of 

compliance costs to revenue; and (2) the firm and facility impact analyses discussed in Chapters 9 

and 10 of the EEBA. 

First, EPA performed an analysis comparing annualized compliance costs to 

revenue for small entities at the firm level. EPA found that none of the small firms are estimated 

to incur compliance costs equaling or exceeding one percent of annual revenue. Second, EPA 

drew on the facility impact analysis, which estimated facility closures and other adverse changes 

to financial condition (referred to as “moderate impacts”). See Chapter 5 of the EEBA for details 

of EPA’s analysis of closures and moderate impacts for privately owned businesses. This analysis 

indicated that the final rule would cause no regulated facilities owned by small entities to close or 

to incur moderate impacts. From these analyses, EPA determined that the final rule will not have 

a significant economic impact on a substantial number of small entities. See Chapter 10 of the 

EEBA for the final rule for a more detailed discussion of the economic impacts on small entities. 

2.2.5 Regulatory History of the Metals Industry 

EPA has promulgated effluent limitations guidelines and standards for 13 metals 

industries. These regulations cover metal manufacturing, metal forming, and component 

finishing, as summarized below. 

2-8

2.0 - Background 

Table 2-2


Summary of Metals Industry Effluent Guidelines


Coverage Area Title CFR Reference 

Metal and Metal Alloy 

Manufacturing 

Iron and Steel Manufacturinga 

Nonferrous Metals Manufacturing 

Ferroalloy Manufacturing 

40 CFR 420 

40 CFR 421 

40 CFR 424 

Metal Forming Iron and Steel Manufacturinga 

Metal Molding and Casting 

Aluminum Forming 

Copper Forming 

Nonferrous Metals Forming and Metal Powders 

40 CFR 420 

40 CFR 464 

40 CFR 467 

40 CFR 468 

40 CFR 471 

Component Finishing Electroplating 

Iron and Steel Manufacturinga 

Metal Finishing 

Battery Manufacturing 

Coil Coating 

Porcelain Enameling 

Electrical and Electronic Component Manufacturing 

40 CFR 413 

40 CFR 420 

40 CFR 433 

40 CFR 461 

40 CFR 465 

40 CFR 466 

40 CFR 469 

Source: Code of Federal Regulations, Part 40.
 a

The Iron and Steel Manufacturing category includes metal manufacturing, metal forming, and component finishing.


In 1986, the Agency reviewed these 13 regulations and identified a significant 

number of metals-processing facilities discharging wastewater that these regulations did not 

cover. Based on this review, EPA performed a detailed analysis of these unregulated sites and 

identified the discharge of significant amounts of pollutants. This analysis resulted in a 

preliminary decision to consider new regulations for a Machinery Manufacturing and Rebuilding 

(MM&R) Point Source Category. In 1989, the Agency published a Preliminary Data Summary 

(PDS) for the MM&R industry, which is located in the MP&M Public Record (Section 1.1, DCN 

M432). The preliminary study of the unregulated MP&M facilities indicated the following: 

� The number of facilities, wastewater flow, and toxic and nonconventional 

pollutant loads were significant; 

� The large quantities of toxic pollutants discharged threatened the treatment 

capability of many POTWs as found by the Domestic Sewage Study; 

� There were gaps in federal regulatory coverage in the electroplating, metal 

finishing, and electrical and electronic components categories; 

� Pollutant concentrations were at treatable levels and at levels as high and 

sometimes higher than concentrations in wastewater from other regulated 

categories; and 

2-9

2.0 - Background 

� Some MP&M operations generate hazardous solid waste and sludge that 

could impact hazardous waste disposal. 

Based on information contained in the PDS, EPA divided the MM&R category 

into two phases by major industrial groups or sectors. The Agency announced its schedule for the 

development of effluent guidelines for two separate MM&R phases in EPA’s January 2, 1990 

Effluent Guidelines Plan (55 FR 80). One of the primary reasons for dividing the category into 

two phases was the large number of facilities (over 900,000) identified in the PDS as potentially 

included in the MM&R Point Source Category. On May 7, 1992, EPA changed the category 

name to Metal Products and Machinery (MP&M) to clarify the coverage of the category (57 FR 

19748). Many questionnaire respondents found the MM&R label confusing and interpreted the 

category to apply only to machinery sites. The Agency believes that the MP&M title more 

accurately describes the coverage of the category. 

As mentioned in Section 2.2.2, NRDC and Public Citizen, Inc. challenged the 

Effluent Guidelines Plan in a suit filed in U.S. District Court for the District of Columbia (NRDC 

et al. v. Browner, Civ. No. 89-2980). Under a consent decree in this litigation, EPA developed a 

plan to promulgate effluent guidelines for, among others, the MP&M Point Source Category. 

The 1992 Effluent Guidelines Plan provided for EPA to propose effluent guidelines for the 

MP&M Phase I Category by November 1994 and take final action by May 1996. Based on a 

motion filed by EPA on September 28, 1994, the court granted an extension for proposal and 

promulgation of the final regulation. To make the regulation more manageable, EPA initially 

divided the industry into two phases based on industrial sectors. The Phase I proposal included 

the following industry sectors: Aerospace; Aircraft; Electronic Equipment; Hardware; Mobile 

Industrial Equipment; Ordnance; and Stationary Industrial Equipment. At that time, EPA 

planned to propose a rule for the Phase II sectors approximately three years after the MP&M 

Phase I proposal. Phase II sectors included: Bus & Truck, Household Equipment, Instruments, 

Job Shops, Motor Vehicles, Office Machines, Precious Metals and Jewelry, Printed Wiring 

Boards, Railroad, Ships and Boats, and Miscellaneous Metal Products. 

On May 30, 1995, EPA published the MP&M Phase I proposal (60 FR 28210). 

EPA proposed effluent limitations guidelines, pretreatment standards, and new source 

performance standards for the seven MP&M Phase I industrial sectors. EPA received over 350 

public comments on the Phase I proposal requesting that the Agency combine all MP&M 

industrial sectors into one effluent guideline. Commentors raised concerns regarding the 

regulation of similar facilities with different compliance schedules and potentially different 

limitations solely based on whether they were in a Phase I or Phase II MP&M industrial sector. 

Furthermore, many facilities performed work in multiple sectors. In such cases, permit writers 

and control authorities (e.g., POTWs) would need to decide which MP&M rule (Phase I or II) 

applied to a facility. 

Based on these comments and after negotiations with NRDC, EPA proposed 

merging the two phases into one rule (61 FR 35042; July 3, 1996). In 1997, EPA obtained 

approval from the U.S. District Court for the District of Columbia to combine MP&M Phases I 

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2.0 - Background 

and II into a single regulation for the 18 MP&M industrial sectors and to extend the effluent 

guidelines schedule (62 FR 8726; February 26, 1997). Extension of the schedule allowed EPA to 

use POTW survey data to develop more precise estimates of administrative burden and allowed 

more extensive stakeholder involvement for data collection. Under the Consent Decree as 

amended, EPA is required to take final action on the MP&M rule by February 14, 2003. 

EPA published a new proposal on January 3, 2001 (66 FR 424), which completely 

replaced the 1995 proposal. EPA proposed to establish new effluent limitations and guidelines 

and standards for 18 MP&M industrial sectors (without any designation of “Phase I or II”) and 

divided the industry into eight regulatory subcategories: General Metals, Metal Finishing Job 

Shops, Printed Wiring Board, Non-Chromium Anodizing, Steel Forming and Finishing, Oily 

Wastes, Railroad Line Maintenance, and Shipbuilding Dry Dock (see 66 FR 439 for a discussion 

of the proposal subcategorization scheme). 

EPA found two basic types of waste streams in the industry: (1) wastewater with 

high metals content (metal-bearing), and (2) wastewater with low concentration of metals and 

high oil and grease content (oil-bearing). When looking at facilities generating metal-bearing 

wastewater (with or without oil-bearing wastewater), EPA identified five groups of facilities that 

could potentially be subcategorized by dominant product, raw materials used, and/or nature of the 

waste generated (i.e., General Metals, Metal Finishing Job Shops, Printed Wiring Board, NonChromium Anodizing, and Steel Forming and Finishing). When evaluating facilities with only 

oil-bearing wastewater for potential further subcategorization, EPA identified two types of 

facilities (i.e., Railroad Line Maintenance and Shipbuilding Dry Dock) that were different from 

the other facilities in the Oily Wastes Subcategory based on size, location, and dominant product 

or activity. This subcategorization scheme allowed EPA to more accurately assess various 

technology options in terms of compliance costs, pollutant reductions, benefits, and economic 

impacts. 

EPA proposed new limits and standards for direct dischargers in all eight MP&M 

subcategories and proposed pretreatment standards for all indirect dischargers in three 

subcategories (i.e., Metal Finishing Job Shops, Printed Wiring Board, and Steel Forming and 

Finishing); pretreatment standards for facilities above a certain wastewater flow volume in two 

subcategories (i.e., General Metals and Oily Wastes); and no national pretreatment standards for 

facilities in three subcategories (i.e., Non-Chromium Anodizing, Railroad Line Maintenance, and 

Shipbuilding Dry Dock). EPA received over 1,500 comment letters on the 2001 proposal. 

On June 5, 2002, EPA published a Notice of Data Availability (NODA) at 67 FR 

38752. In the NODA, EPA discussed major issues raised in comments on the 2001 proposal; 

suggested revisions to the technical and economic methodologies used to estimate compliance 

costs, pollutant loadings, and economic and environmental impacts; presented the results of these 

suggested methodology changes and incorporation of new (or revised) data; and summarized the 

Agency’s thinking on how these results could affect the Agency’s final decisions. 

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2.0 - Background 

The NODA also included a discussion of possible alternative options for certain 

subcategories based on comments, including an Environmental Management System (EMS) 

alternative in lieu of Part 438 limitations and standards, and a discussion of “upgrading” sites 

currently regulated under the Electroplating regulations (40 CFR 413) to meet the Metal 

Finishing regulations (40 CFR 433) (see 67 FR 38797). Finally, the NODA included preliminary 

revised effluent limitations and pretreatment standards for all eight proposed subcategories. EPA 

received over 300 comment letters on the NODA. EPA’s responses to comments on the May 

1995 proposal, January 2001 proposal, and June 2002 NODA can be found in Section 20.3 of the 

rulemaking record. 

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3.0 - Data Collection Activities 

3.0 DATA COLLECTION ACTIVITIES 

This section summarizes the Agency’s data collection activities for the MP&M 

rulemaking effort. Section 3.1 summarizes the 1989 and 1996 MP&M industry questionnaires 

including their purpose, recipient selection process, types of information collected, and uses of 

data. Sections 3.2 and 3.3 summarize the site visit and field sampling programs, respectively, 

conducted at facilities performing proposed MP&M operations.1 Sections 3.4, 3.5, and 3.6 

discuss other data sources. 

3.1 Industry Questionnaires 

EPA distributed two screener and six detailed questionnaires (surveys) as part of 

the data collection effort for the MP&M rulemaking. As discussed in Section 2.0, EPA initially 

divided the MP&M Point Source Category into two phases by major industrial sectors. The 

surveys distributed for the seven Phase I industrial sectors requested data reflecting 1989 

operations, and the surveys distributed for the 11 Phase II industrial sectors requested data 

reflecting 1996 operations. The table below lists the industry surveys and the distribution dates. 

Sections 3.1.1 and 3.1.2 discuss these questionnaire efforts. 

Distribution of the MP&M Industry Surveys 

Type of Survey Survey Name Distribution Date 

Screener 1989 Screener Survey 

1996 Screener Survey 

1996 Benefits Screener 

8/90 

12/96 

10/98 

Detailed 1989 Detailed Survey 

1996 Long Detailed Survey 

1996 Short Detailed Survey 

1996 Municipality Detailed Survey 

1996 POTW Detailed Survey 

1996 Federal Detailed Survey 

1/91 

6/97 

9/97 

6/97 

11/97 

4/98 

During the same time that EPA was developing the MP&M Point Source 

Category rulemaking, EPA was also updating the effluent limitations guidelines and standards 

for the Iron and Steel Point Source Category. As part of the revised Iron and Steel rulemaking, 

EPA distributed detailed and short surveys to iron and steel facilities. Following receipt of the 

1997 Iron and Steel Surveys, EPA evaluated whether some facilities may be more appropriately 

covered under the MP&M Point Source Category. 

1

Note: EPA evaluated a number of unit operations for the May 1995 proposal, January 2001 proposal, and June 2002 

NODA (see Tables 4-3 and 4-4). However, EPA selected a subset of these unit operations for regulation in the final 

rule (see Section 1.0). For this Section, the term “proposed MP&M operations” means those operations evaluated 

for the two proposals, NODA, and final rule. The term “final MP&M operations” means those operations defined as 

“oily operations” (see Section 1.0, 40 CFR 438.2(f), and Appendix B to Part 438) and regulated by the final rule. 

3-1 
3.0 - Data Collection Activities 

EPA included data from 154 iron and steel surveys in the MP&M survey database 

and proposed to create a new subcategory, the Steel Forming and Finishing Subcategory in the 

MP&M Point Source Category (see 66 FR 424). Based on comments on the January 2001 

proposal and June 2002 NODA EPA concluded that those operations included in the proposed 

Steel Forming and Finishing Subcategory should remain subject to effluent guidelines at the Iron 

and Steel Point Source Category (40 CFR 420). See Section 6.0 for further discussion of 

subcategorization. 

For this final rule, EPA also evaluated portions of the iron and steel surveys to 

determine if continuous electroplaters would be more appropriately covered under the MP&M 

Point Source Category, as described in the Notice of Data Availability (NODA) (67 FR 38752; 

June 5, 2002). EPA included these facilities in the General Metals Subcategory for evaluating 

options for the final rule. See Section 6.0 for further discussion of this determination. EPA has 

data for 47 continuous electroplating lines at 24 sites. The data for these lines were evaluated in 

developing the final MP&M effluent limitation guidelines and standards (see Section 3.1.3 for 

further discussion). A blank copy of the Iron and Steel Surveys and the relevant data from the 24 

surveys are available in Section 5.3.6, DCN 16147 and Section 15.4.3 of the rulemaking record. 

3.1.1 The 1989 Industry Surveys 

EPA distributed a screener and a detailed survey for the Phase I MP&M proposed 

regulation to manufacturing, rebuilding, and/or maintenance facilities engaged in the following 

seven industrial sectors: 

� Aerospace;


� Aircraft;


� Electronic Equipment;


� Hardware;


� Mobile Industrial Equipment;


� Ordnance; and


� Stationary Industrial Equipment.


The 1989 screener and detailed surveys are discussed below. EPA describes in 

detail the recipient selection, stratification schemes, and the type and potential use of the 

requested information in the Information Collection Request (ICR) for the 1989 screener and 

detailed MP&M industry surveys. The ICR can be found in Section 3.6.2 of the rulemaking 

record, DCN M15738. 

3.1.1.1 1989 Screener Survey 

In August and September 1990, EPA mailed 8,342 screener surveys (also referred 

to as the Mini Data Collection Portfolio (MDCP)) to sites believed to be engaged in 

manufacturing, rebuilding, or maintenance activities in one of the seven industrial sectors listed 

above. Mailout of the screener was the preliminary step in an extensive data-gathering effort for 

3-2

3.0 - Data Collection Activities 

these seven industrial sectors. The purpose of the screener was to identify sites to receive the 

more detailed survey and to make a preliminary assessment of these seven industrial sectors. 

1989 Screener Recipient Selection and Distribution 

EPA identified potential recipients from a Dun & Bradstreet database using 

Standard Industrial Classification (SIC) codes. The Agency identified more than 190 SIC codes 

applicable to the seven industrial sectors listed in Section 3.1.1. Within each sector, EPA 

identified between 1 and 40 SIC codes. EPA calculated the number of sites to receive the 

screener within each SIC code by a coefficient of variation (CV) minimization procedure, 

described in the Statistical Summary for the Metal Products & Machinery Industry Surveys 

(Section 10.0, DCN 16118). Based on the number of sites selected within each SIC code, the 

Agency purchased a list of randomly selected names and addresses from the Dun & Bradstreet 

database for each SIC code. This list included twice the number of sites specified by the CV 

minimization procedure for each SIC code. 

EPA deleted sites from the purchased Dun & Bradstreet list for the following 

reasons: sites had SIC codes that were inconsistent with company names; sites were corporate 

headquarters without manufacturing, rebuilding, or maintenance operations; or sites had 

insufficient mailing addresses. EPA then randomly selected 30 to 60 sites within each SIC code 

and assigned each site a randomly selected identification number. EPA assigned each site 

identification number a corresponding barcode to track the distribution and processing of the 

screeners. 

To examine trends and similarities in manufacturing across the industry sectors, 

EPA also sent screener surveys to some facilities performing manufacturing in the following 

eight industrial sectors: 

� Bus and Truck;


� Household Equipment;


� Instruments;


� Motor Vehicles;


� Office Machines;


� Precious and Nonprecious Metals;


� Railroad; and


� Ships and Boats.


The Agency did not send the screener to sites whose SIC codes indicated that they were engaged 

in only rebuilding or maintenance (i.e., not manufacturing) operations in the eight industrial 

sectors listed above. 

EPA maintained a toll-free helpline from August through October of 1990 to 

assist screener recipients in completing the survey. This helpline received approximately 900 

calls from screener recipients. Additional information about the screener mailing (e.g., a copy of 

3-3

3.0 - Data Collection Activities 

the screener, specific mailing and processing procedures, non-CBI screener responses, follow-up 

letters, and notes from helpline telephone conversations) is contained in Sections 3.7, 3.8 and 5.3 

of the rulemaking record. 

1989 Screener Mailout Results 

EPA mailed 8,000 screener surveys in August 1990. Based on the number of 

surveys returned undelivered, EPA mailed an additional 342 in September 1990. In addition, 

EPA received 22 unsolicited responses to the survey. Of the 8,364 potential respondents to the 

screener, including those who provided unsolicited responses, 7,846 received the screener. 

Screeners for the remaining 518 were returned to EPA as undeliverable. EPA assumed these 

sites to be out of business. Of the total potential respondents, 84 percent (6,981) returned the 

screener to EPA. A blank copy of the screener form and nonconfidential portions of the 

completed screeners are contained in the rulemaking record (see Section 3.7.2, DCN 17223, and 

Sections 3.7.1 and 5.3.7). Table 3-1 and Figure 3-1 summarize the mailout results for the 1989 

and 1996 survey efforts. 

Information Collected 

The Agency requested the following site-specific information in the 1989 

screener: 

� Name and address of facility; 

� Contact person; 

� Parent company; 

� Sectors in which the site manufactures, rebuilds, or maintains machines or 

metal components; 

� SIC codes corresponding to products at the site; 

� Number of employees; 

� Annual revenues; 

3-4

-- -- --

Table 3-1


1989 and 1996 MP&M Survey Mailout Results


Survey Type Mailed 

Returned 

Undelivered 

Returned 

(%) 

Not 

Returned 

(%) 

Respondents 

Performing Proposed 

MP&M Operations 

(%) 

Respo

Propo

and R

only 

1989 Screener Survey 8,342 518 6,981a (84) 865 (11) 3,598 (52) 1989 Detailed Survey 1,020 0 998b (98) 22 (2) 792 (79) 1996 Screener Survey 5,325 579 4,248d (80) 497 (10) 2,424 (57) 1996 Benefits Screener 1,750 155 1,392 (80) 161 (10) 1,354 (97) 1996 Long Detailed Survey 353 1 311b (88) 41 (12) 303c (97) 1996 Short Detailed Survey 101 1 83 (82) 17 (17) 59 (71) 1996 Municipality Detailed Survey 

150 2 147 (98) 1 (1) 144 (53)f 

1996 Federal Detailed Survey 51 (--) 44 (86) 

3-5


Source: 1989 and 1996 Survey Tracking Systems (see Section 8.8.1, DCN 16331, and Section 5.3, DCN 16330 of the rulemaking recoraIncludes 22 unsolicited responses.
bSeven of the 1989 detailed surveys and two of the 1996 long detailed surveys were returned too late to be incorporated into the detailed cIncludes long survey respondents that discharge <1 mgy.
dDoes not include one duplicate survey received.
eNumber of respondents also includes sites with classified process information (1989 detailed survey), sites with insufficient data (1996 

returned too late to incorporate into the database (1996 long survey). The data from these surveys were not incorporated into the survey 

fFor the municipality survey, these numbers represent the number and percentage of POTWs receiving wastewater from facilities evalua

the number and percentage of POTWs not receiving wastewater from facilities evaluated in the final rule.


-- Not applicable to the survey.

1996 Federal Detailed 

1996 POTW Detailed 

1996 Municipality Detailed 

1996 Short Detailed 

1996 Long Detailed 

1996 Benefits Screener 

1996 Screener 

1989 Detailed 

1989 Screener 52% 

57% 

71% 

53% 

NA 

3-6
Survey Type 

0% 10% 20% 30% 40% 50% 60% 70% 8

Percentage 

Surveys Returned Respondents Engaged in MP&M Operations 

NA - The number of federal surveys distributed is not certain, and the percentage of returned surveys cannot be calculated. 

Figure 3-1. Percentage of 1989 and 1996 MP&M Surveys Returned and 

Percentage of Survey Respondents Performing Proposed MP&M Operation
3.0 - Data Collection Activities 

� Unit operations performed at the site; 

�

Whether there is process water use and/or wastewater discharge for each 

unit operation performed at the site; and 

� Base metal(s) on which each unit operation is performed. 

The Agency used a computerized database system (MS Access 97) to store and analyze data 

received from the screeners. The database dictionary and all nonconfidential screener surveys are 

located in Section 5.3.7 of the rulemaking record. 

EPA determined the number of sites engaged in proposed MP&M operations by 

responses to the screener. As shown in Table 3-1, approximately 52 percent of the 1989 screener 

survey respondents reported that their sites were engaged in proposed MP&M operations and 

approximately 48 percent reported no or only dry proposed MP&M operations at their sites. 

EPA could not determine the status of 10 of the sites because they returned incomplete screeners 

and did not respond to follow-up efforts. 

The Agency contacted a statistically representative sample of the nonrespondent 

sites (i.e., sites that did not return the screener) and sites reporting “not engaged” in proposed 

MP&M operations to determine whether their responses were due to confusion over the scope of 

the industry. Based on the results of this follow-up, EPA adjusted the survey weights for 

misclassification and incorrect responses. The methodology for calculating the adjustment 

factors is provided in the Statistical Summary for the Metal Products & Machinery Industry 

Surveys (Section 10.0, DCN 16118). 

1989 Screener Data Entry, Engineering Coding, and Analysis 

EPA reviewed all of the screener surveys prior to data entry. As part of this effort, 

the Agency reviewed all documentation provided by the site, corrected errors and deficiencies, 

and coded the information for data entry. In some cases, these revisions required telephone 

contact with site personnel. The Agency contacted more than 1,100 screener recipients to resolve 

survey deficiencies and code information for data entry. Following preliminary review, EPA 

entered the scannable data (i.e., responses to multiple-choice, Mark SenseTM questions) into the 

database using a ScantronTM reader. EPA scanned each form twice and compared the 

information using a computer program as a quality control check. The Agency performed double 

key-entry of nonscannable data, resolved any inconsistencies, and converted the data to database 

files. 

Based on the screener mailout results, EPA developed an industry profile for the 

seven sectors. The screener database report provides estimates of the national population for 

sites in these industrial sectors with regard to water use characteristics, size, location, sector, unit 

operations, and metal types. The Statistical Summary for the Metal Products & Machinery 

3-7

3.0 - Data Collection Activities 

Industry Surveys (Section 10.0, DCN 16118) discusses the sample size determination and 

statistical procedures for developing national estimates for the industry. 

3.1.1.2 1989 Detailed Survey 

Based on responses to the 1989 screener, EPA sent a more detailed survey to a 

select group of water-using facilities performing proposed MP&M operations. This survey, also 

referred to as the data collection portfolio (DCP), was designed to collect detailed technical and 

financial information reflecting a site’s 1989 operations. EPA used this information to 

characterize these facilities from the seven industrial sectors, develop pollutant loadings and 

reductions, and develop compliance cost estimates, as discussed later in this document. 

EPA mailed 896 detailed surveys in January 1991. Based on the number of 

detailed surveys returned undelivered, EPA mailed an additional 124 detailed surveys in January 

and February 1991, for a total of 1,020 detailed surveys mailed. A blank copy of the 1989 

detailed survey (Section 3.7.2, DCN 17224) and copies of the nonconfidential portions of the 

completed detailed surveys are located in Section 5.3.8 of the rulemaking record. 

1989 Detailed Survey Recipient Selection and Distribution 

EPA selected 1,020 sites to receive detailed surveys from the following three 

groups of sites: 

� Water-discharging 1989 screener respondents (860 sites); 

�

Water-using 1989 screener respondents that did not discharge process 

water (74 sites); and 

�

Water-discharging sites from key companies performing proposed MP&M 

operations that did not receive the 1989 screener (86 sites). 

The methods used to select sites within each group are described below. 

The Agency mailed the 1989 detailed survey to all 860 water-discharging screener 

respondents. EPA’s intent in collecting detailed data from all 860 sites was to characterize the 

potential variations in unit operations performed and water-use practices among waterdischarging sites in these seven industrial sectors. 

The Agency mailed the 1989 detailed survey to a probability sample of 50 

screener respondents that reported using but not discharging process water. EPA selected these 

sites to provide information on water-use practices at sites that use but do not discharge process 

water, and to determine if “zero-discharge” practices used at those sites could be used at other 

facilities performing proposed MP&M operations. In addition to the 50 probability sample sites, 

EPA mailed the 1989 detailed survey to 24 screener respondents that reported using but not 

3-8

3.0 - Data Collection Activities 

discharging process water. The Agency selected these sites because they performed unit 

operations that were not expected to be sufficiently characterized by detailed surveys mailed to 

other sites. The unit operations that EPA expected at each of the 24 sites are listed in Section 

3.8.2 of the rulemaking record. 

EPA mailed the 1989 detailed survey to 86 sites that did not receive the 1989 

screener. The Agency identified these sites as representing key companies in the industry that 

EPA did not select as 1989 detailed survey recipients based on the screener mailout. EPA 

identified key companies from Dun & Bradstreet company lists, the Thomas Register, Fortune 

Magazine’s list of the top 500 U.S. companies, and MP&M site visits at companies with annual 

revenues of $50 million or more that EPA believed to be leading companies in their particular 

industrial sector. The Agency contacted each of the key companies to identify sites within the 

company that were performing proposed MP&M operations and used process water to perform 

these operations. Records of these follow-up telephone calls are located in the MP&M 

rulemaking record (see Section 3.8.2). EPA did not use these 86 surveys for developing the 

national estimates because the Agency did not randomly select these facilities. 

EPA operated a toll-free telephone helpline from January until July 1991 to assist 

recipients in completing the 1989 detailed survey. The helpline received approximately 1,400 

calls from detailed survey recipients. Callers to the 1989 detailed survey helpline typically 

requested the following: 

�

Assistance with the technical sections of the detailed survey (e.g., 

technical clarification of unit operation definitions); 

� Additional time to complete the survey; 

�

Assistance with the financial sections of the detailed survey (these calls 

were referred to a separate economics helpline); or 

�

Clarification of the applicability of the survey (i.e., did the survey apply to 

the site?). 

Records for nonconfidential telephone calls to the helpline and to EPA personnel are located in 

Section 5.3.8 of the rulemaking record. 

1989 Detailed Survey Mailout Results 

Table 3-1 summarizes the results of the detailed survey mailout. Of the 1,020 

sites that received the detailed survey, 998 responded to the survey and 22 did not. EPA did not 

include 199 of the 1,020 sites that responded in the detailed survey database for one of the 

following reasons: 

� The site was out of business; 

3-9

3.0 - Data Collection Activities 

� The site did not use process water; 

� The site was not performing proposed MP&M operations; or 

�

Process information at the site was Department of Defense or Department 

of Energy classified information. 

Specific reasons for not using data from these sites are documented in Section 5.3.8.2 of the 

rulemaking record. 

Upon review of the detailed surveys submitted by these sites, EPA determined 87 

sites to be in the other 11 industrial sectors rather than the seven sectors identified in Section 

3.1.1. Because the scope of the detailed survey mailout effort included only sites from the seven 

industrial sectors listed in Section 3.1.1, EPA did not include these 87 sites in the detailed survey 

database. 

Information Collected 

The Agency designed the 1989 detailed survey to collect information necessary to 

develop effluent limitations guidelines and standards for the MP&M rulemaking. EPA divided 

the detailed survey into the following parts: 

� Part I - General Information;


� Part II - Process Information;


� Part III - Water Supply;


� Part IV - Wastewater Treatment and Discharge;


� Part V - Process and Hazardous Wastes; and


� Part VI - Financial and Economic Information. 


The detailed survey instructions and the ICR for this project contain further details 

on the types of and potential uses for information collected. These documents are located in 

Section 3.7.2 of the rulemaking record, DCN 17224. 

Part I (questions 1 through 13) requested information necessary to identify the 

site, to characterize the site by certain variables, and to confirm that the site was performing 

proposed MP&M operations. This information included: site name, address, contact person, 

number of employees, facility age, average energy usage, discharge permit status, and MP&M 

activity (manufacturing, rebuilding, or maintenance). 

Part II (questions 14 through 21) requested detailed information on products, 

production levels, unit operations, activity, water use for unit operations, wastewater discharge 

from unit operations, miscellaneous wastewater sources, waste minimization practices (e.g., 

pollution prevention), and air pollution control for unit operations. EPA requested the site to 

provide detailed technical information (e.g., water balance, chemical additives, metal type 

3-10

3.0 - Data Collection Activities 

processed, disposition of wastewater) for each proposed MP&M operation and air pollution 

control device using process water. This section also requested information on unique and/or 

auxiliary operations. EPA used this information to evaluate raw waste characteristics, water use 

and discharge practices, and sources of pollutants for each proposed MP&M operation. 

Part III (question 22) requested information on the water supply for the site. EPA 

requested the site to specify the source water origin, average intake flow, average intake 

operating hours, and the percentage of water used for proposed MP&M operations. EPA used 

this information to evaluate overall water use for the site. 

Part IV (questions 23 through 33) requested detailed information on influent and 

effluent wastewater treatment streams and wastewater treatment operations. The information 

requested included: the origin of each stream contributing to the site’s overall wastewater 

discharge; a block diagram of the wastewater treatment system; detailed technical information 

(e.g., wastewater stream flow rates, treatment chemical additives, system capacity, disposition of 

treatment sludge) for each wastewater treatment operation; self-monitoring data; and capital and 

operating cost data. EPA collected this information on facilities performing proposed MP&M 

operations to: (1) evaluate treatment in place at these facilities; (2) develop and design a cost 

model to estimate various control options; and (3) assess the long-term variability of effluent 

streams. 

Part V (question 34) requested detailed information on the types, amounts, and 

composition of wastewater and solid/hazardous wastes generated during production or waste 

treatment, and the costs of solid waste disposal. EPA collected this information to evaluate the 

types and amounts of wastes currently discharged, the amount of waste that is contract hauled off 

site, and the cost of contract hauling wastes. 

Part VI requested detailed financial and economic information from the site and 

the company owning the site. EPA collected this information to calculate the economic impacts 

of the regulatory options considered for the MP&M rulemaking. 

1989 Detailed Survey Review, Coding, and Data Entry 

The Agency completed an engineering review of the detailed surveys, including 

coding responses to questions from Parts I through V to facilitate entry of technical data into a 

database. The MP&M DCP Database Dictionary identifying all database codes developed for 

this effort and the database dictionary for Section VI of the detailed survey are located in Section 

5.3.8.2 of the rulemaking record, DCN 17387. 

The Agency followed up with telephone calls to all respondents who did not 

provide: (1) information on operations (manufacturing, rebuilding, or maintenance) or sectors; 

(2) metal type or unit operation descriptions for each water-using unit operation; or 

(3) descriptions for each wastewater treatment operation. EPA also made follow-up calls to 

3-11

3.0 - Data Collection Activities 

clarify incomplete or contradictory technical or economic information. EPA confirmed all 

information obtained from follow-up calls by sending a letter to the site. 

EPA developed a database to store all technical data provided in the detailed 

surveys. After engineering review and coding, the Agency entered data from the detailed surveys 

into the database using a double key-entry and verification procedure. EPA coded and entered 

data from 792 detailed survey respondents determined to be performing proposed MP&M 

operations into the detailed survey database. The MP&M DCP Database Dictionary presents the 

database structure and defines each field in the detailed survey database and the codes that 

describe data in these fields. 

The Economic, Environmental, and Benefits Analysis of the Proposed Metal 

Products and Machinery Rule, which is located in Section 8.1 of the rulemaking record, DCN 

2000, discusses EPA’s review of Section VI of the detailed survey. 

1989 Detailed Survey Data Analysis 

EPA used the information collected in the detailed survey to develop an industry 

profile and to identify the baseline of treatment in place and estimate the amount of pollutant 

discharges from facilities performing proposed MP&M operations. Section 4.0 of this document 

provides estimates of the national population of these facilities that discharge water with regard 

to size, location, sector, unit operations, metal types, and discharge flows, and discusses the 

statistical procedures for developing national estimates for the industry. Section 11.0 and 12.0 

present the methodologies used to estimate pollutant discharges and compliance costs, 

respectively. 

3.1.2 The 1996 Industry Surveys 

Between 1996 and 1998, EPA distributed one screener and five detailed surveys, 

requesting data representing the survey recipients’ 1996 operations. The five detailed surveys 

included the long, short, municipality, federal, and publicly owned treatment works (POTW) 

surveys. The Agency distributed the 1996 surveys to commercial and government (federal, state, 

and local) facilities that manufacture, rebuild, or maintain metal products or parts to be used in 

one of the following 11 industrial sectors: 

� Bus and Truck; 

� Household Equipment; 

� Instruments; 

� Job Shops; 

� Motor Vehicles; 

� Office Machines; 

� Precious Metals and Jewelry; 

� Printed Wire Boards; 

� Railroad; 

3-12

3.0 - Data Collection Activities 

� Ships and Boats; and 

� Miscellaneous Metal Products. 

The 1996 screener and detailed surveys are discussed below. Recipient selection, stratification 

schemes, and the type and potential use of the information requested are described in more detail 

in the ICR for the 1996 screener (see Section 3.5.1, DCN 15766). 

3.1.2.1 1996 Screener Survey 

In December 1996 and February 1997, EPA distributed 5,325 screener surveys to 

sites believed to be engaged in manufacturing, rebuilding, or maintenance activities in one of the 

11 industrial sectors listed in Section 3.1.2. The purpose of the screener surveys was to identify 

sites to receive the more detailed survey and to make a preliminary assessment of the industry for 

the 11 industrial sectors. EPA sent an additional 1,750 screeners to facilities located in Ohio (a 

state with a high concentration of facilities performing proposed MP&M operations) as part of a 

benefits study. The Agency used these screeners to collect data to analyze environmental 

benefits. 

1996 Screener Recipient Selection and Distribution 

As discussed above, EPA sent the 1996 screener survey to 5,325 randomly 

selected facilities performing proposed MP&M operations (includes replacement sites). The 

Agency selected potential recipients from the Dun & Bradstreet database based on the industrial 

sector (using the SIC code), activity (i.e., manufacturing, maintenance, or rebuilding), size as 

measured by number of employees, and wastewater discharge flow rate. 

The Agency identified more than 126 SIC codes applicable to the 11 industrial 

sectors. Within each sector, EPA identified between 1 and 26 SIC codes. EPA calculated the 

number of sites to receive the 1996 screener within each SIC code by a coefficient of variation 

(CV) minimization procedure described in the Statistical Support Document located in Section 

10.0 of the rulemaking record, DCN 16119. Based on the number of sites selected within each 

SIC code, the Agency obtained a list of randomly selected names and addresses from Dun & 

Bradstreet. This list included twice the number of sites specified by the CV minimization 

procedure for each SIC code. EPA randomly selected the initial list of sites from the Dun & 

Bradstreet database for each SIC code. 

After reviewing the potential sites, EPA deleted sites for the following reasons: 

� The site was a corporate headquarters without manufacturing, rebuilding, 

or maintenance operations; 

� The site received a 1989 screener or detailed survey; 

3-13

3.0 - Data Collection Activities 

� The site was a duplicate of another facility in the list of potential facilities 

performing proposed MP&M operations; 

� The site had an SIC code that was inconsistent with company name; or 

� The site had an insufficient mailing address. 

EPA established a toll-free telephone helpline and an electronic mail address to 

assist screener recipients in completing the survey. EPA received helpline calls and electronic 

mail inquiries from more than 600 screener recipients. Nonconfidential notes from helpline and 

review follow-up calls are located in Section 5.3.1 of the rulemaking record. 

1996 Screener Mailout Results 

EPA initially mailed 4,900 surveys in December 1996. The Agency distributed 

surveys to an additional 425 sites to replace surveys that were returned undelivered. EPA 

assumed the undeliverable survey sites to be out of business. Of the 5,325 surveys mailed, 80 

percent (4,248) of the recipients returned completed surveys to EPA. A blank copy of the 1996 

screener (see Section 3.7.1, DCN 16367) and nonconfidential portions of the completed screeners 

are located in the public record for this rulemaking (see Section 5.3.1.1). Table 3-1 and Figure 3-

1 summarize the MP&M survey mailout results. 

The Agency contacted a statistically representative sample of nonrespondent sites 

to determine whether these sites were performing proposed MP&M operations and discharged 

process wastewater. Only 24 percent of the nonrespondents contacted were performing proposed 

MP&M operations, and approximately half of these facilities did not discharge process 

wastewater. 

Information Collected 

The Agency requested the following site-specific information in the screener: 

� Name and address of facility; 

� Contact person; 

� Whether process water is used at the site; 

� Destination of process wastewater discharged; 

� Volume of process wastewater discharged; 

� Number of employees; 

3-14

3.0 - Data Collection Activities 

� Annual revenue; 

� Sectors in which the site manufactures, rebuilds, or maintains machines or 

metal components; and 

� Unit operations performed at the site and whether there is water use and/or 

wastewater discharge for each unit operation performed at the site. 

The Agency used a computerized database system (MS Access 97) to store and 

analyze data received from the 1996 screeners. Nonconfidential portions of the screener surveys 

(see Section 5.3.1.1) and the database dictionary are located in the public record for this 

rulemaking (see Section 5.3.1.2, DCN 15393). 

1996 Screener Data Review and Data Entry 

EPA reviewed the 1996 screener survey responses for accuracy and consistency 

and formatted the information for data entry. The Agency contacted approximately 1,800 

screener respondents to resolve deficient and inconsistent information prior to data entry. 

Following review, EPA double key entered and compared the data from the formatted screeners, 

using a computer program, as a quality control check. The Agency then reviewed the database 

files for deficiencies and inconsistencies, and resolved all issues for the final survey database. 

1996 Benefits Screener Survey 

For an environmental benefits study, EPA sent the 1996 screener survey to 1,750 

(including replacement sites) randomly selected sites in Ohio, a state with a large number of 

facilities performing proposed MP&M operations. The selection criteria and sampling frame for 

the benefits screener recipients are described in more detail in memoranda located in Section 

3.8.1.7 of the rulemaking record, DCN 16333. 

The Agency initially mailed the benefits screener to 1,600 facilities in October 

1998. EPA mailed screeners to an additional 150 facilities in February 1999 to replace surveys 

that were returned undelivered. The Agency assumed the undeliverable survey sites to be out of 

business. Of the 1,750 surveys mailed, 80 percent (1,392) of the recipients returned completed 

screeners to EPA. A blank copy of the 1996 benefits screener (see Section 3.7.1, DCN 16367) 

and nonconfidential portions of the completed benefits screeners (see Section 8.8.1) are located 

in the public record for this rulemaking. Table 3-1 and Figure 3-1 summarize the MP&M 

mailout results. 

EPA established a toll-free telephone helpline and an electronic mail address to 

assist screener recipients in completing the survey. EPA received helpline calls and electronic 

mail inquiries from more than 900 benefits screener recipients. Nonconfidential notes from 

helpline and review follow-up calls are located in Section 8.8.1 of the public record for this 

rulemaking. 

3-15

3.0 - Data Collection Activities 

The Agency followed the same review, data entry, and database development 

procedures used for the original 1996 screener survey. EPA contacted more than 400 screener 

respondents to resolve deficient and inconsistent information prior to data entry. The benefits 

screener database is discussed in the Economic, Environmental, and Benefits Analysis of the 

Proposed Metal Products and Machinery Rule. 

3.1.2.2 1996 Long Detailed Survey 

EPA distributed the long detailed surveys (long survey) in June 1997 to 353 

wastewater-discharging facilities performing proposed MP&M operations. EPA designed this 

survey to gather detailed technical and economic information required to develop the MP&M 

effluent limitations guidelines and standards. The long survey is discussed below. 

1996 Long Survey Recipient Selection and Distribution 

In June 1997, EPA sent the long survey to all 353 1996 screener respondents who 

indicated they performed operations in one of the 11 industry sectors listed in Section 3.1.2 and 

discharged one million or more gallons of MP&M process wastewater annually. EPA established 

a toll-free telephone helpline and an electronic mail address to assist long survey recipients in 

completing the survey. EPA received helpline calls and electronic mail inquiries from 

approximately 200 long survey recipients. Nonconfidential notes from helpline and review 

follow-up calls are located in Section 5.3.2.1 of the public record for this rulemaking. 

1996 Long Survey Mailout Results 

Of the 353 surveys mailed, 88 percent (311) of the recipients returned completed 

surveys to EPA. One survey was returned as undelivered and EPA assumed the facility to be out 

of business. A blank copy of the 1996 long survey (Section 3.7.1, DCN 713) and nonconfidential 

portions of the completed long surveys are located in Section 5.3.2.1 of the public record for this 

rulemaking. Table 3-1 and Figure 3-1 summarize the MP&M survey mailout results. 

Information Collected 

EPA divided the long detailed survey into the following sections: 

� Section I: General Site Information; 

� Section II: General Process Information; 

� Section III: Specific Process Information; 

3-16

3.0 - Data Collection Activities 

� Section IV: Economic Information; and 

� Section V: Voluntary Supplemental Information. 

Table 3-2 summarizes the information requested in the 1996 long, short, federal, and 

municipality detailed surveys by question number. EPA designed these surveys to collect similar 

detailed process information from different audiences, as discussed below for each survey. 

Further details on the types of information collected and the potential uses of the information are 

contained in the ICR for this data collection (see Section 3.5.1, DCN 15766) and in the survey 

instructions that are located in Section 3.7.1 of the rulemaking record, DCN 713. 

Section I requested information to determine if the facility was performing 

proposed MP&M operations. Question 1 requested the site to identify the industry sector and 

type of activity (manufacturing, rebuilding, or maintenance) performed. 

Section II requested information to identify the site location and contact person, 

number of employees, facility age, process wastewater discharge status and destination, and 

wastewater discharge permits and permitting authority. This section also requested general 

information about metal types processed, products and production levels, water use for unit 

operations, and wastewater discharge from unit operations. EPA used the process information to 

evaluate water use and discharge practices and sources of pollutants for each proposed MP&M 

operation. 

Section III requested detailed information on wet proposed MP&M operations, 

pollution prevention practices, wastewater treatment technologies, costs for water use and 

wastewater treatment systems, and wastewater/sludge disposal costs. EPA also requested the site 

to provide block diagrams of the production process and the wastewater treatment system. The 

unit operation information requested included: metal types processed, production rate, operating 

schedule, chemical additives, volume and destination of process wastewater and rinse waters, inprocess pollution prevention technologies, and in-process flow control technologies. The 

information requested for each wastewater treatment unit included: operating flow rate, design 

capacity, operating time, chemical additives, and unit operations discharging to each treatment 

unit. In addition, EPA requested the site to provide the type of any wastewater sampling data 

collected. EPA used these data to characterize the industry, to perform subcategorization 

analyses, to identify best management practices, to evaluate performance of the treatment 

technology for inclusion in the regulatory options, and to develop regulatory compliance cost 

estimates. 

Section IV requested detailed financial and economic information about the site or 

the company owning the site. EPA collected this information to calculate the economic impacts 

of the regulatory options considered for the MP&M rulemaking. 

Section V requested supplemental information on other facilities performing 

proposed MP&M operations owned by the company. EPA included this voluntary section to 

3-17

---

--- ---

--- ---

--- ---

--- ---

--- ---

--- ---

--- ---

--- --- ---

---

---

---

---

---

--- 

3.0 - Data Collection Activities 

measure the combined impact of proposed MP&M effluent guidelines on companies with 

multiple facilities 

Table 3-2 

Summary of 1996 Detailed Survey Information by Question Number 

Survey Question Number 

Type of Information Requested 

Long and 

Federal Short Municipality 

Section I 

1 

Section I 

1 

Part II 

1 Industrial sector activities 

Section II 

2-5 

Section II 

2-5 2-5 Site location and facility contact 

6, 7 6, 7 5, 6 Number of employees and age of site 

8, 9 8, 9 7, 8 Discharge status and destination 

10 10 9 Permits under miscellaneous categorical effluent guidelines 

11-12 10-11 Types of end-of-pipe wastewater treatment units 

11 13 12 Metal types processed 

12 15 13 5 major products (quantity and sector) 

13 16 14 Unit operations: water use and associated rinses 

Section III 

14-15 General water use and costs 

16 Production process diagram 

17-23 Detailed description of wet unit operations performed 

24-29 

Section II 

17 16 In-process pollution prevention technologies or practices 

30 Wastewater treatment (WWT) diagram 

31-41 Detailed design and operating parameters of WWT units 

42 WWT costs by treatment unit 

43-44 

Section II 

14 15 Wastewater sampling and analysis conducted 

45 Contract haul and disposal costs 

Facility comments page 

Section IV 

1-9 

Section IV 

1-8 

Part I 

1-3 Financial and economic data 

Section V 

1 

Section V 

1 

Parent firm name and contact, number of other facilities 

performing proposed MP&M operations 

2 2 Number of employees for other facility(ies) 

3 3 Industrial and activity 

2, 4 2, 4 Discharge status and destination 

5 5 Unit operations: water use and discharge status 

Question is not applicable to this survey. 

3-18 
3.0 - Data Collection Activities 

performing proposed MP&M operations that discharge process wastewater. This section 

requested the same information collected in the 1996 MP&M screener survey. Responses to 

questions in this section provided the size, industrial sector, revenue, unit operations, and water 

usage of the company’s other facilities performing proposed MP&M operations. 

1996 Long Survey Data Review and Data Entry 

EPA completed a detailed engineering review of Sections I through III of the 

detailed long survey to evaluate the accuracy of technical information provided by the 

respondents. During the engineering review, EPA coded responses to facilitate entry of technical 

data into the long survey database. The MP&M 1996 Long Survey Database Dictionary 

identifies the database codes developed for this project, and is located in Section 5.3.2.2 of the 

rulemaking record, DCN 15773. EPA contacted approximately 240 long survey respondents, by 

telephone and letter, to clarify incomplete or inconsistent technical information prior to data 

entry. 

The Agency developed a database for the technical information provided by 

survey respondents. After engineering review and coding, EPA entered data from 303 long 

surveys into the database using a double key-entry and verification procedure. The MP&M 1996 

Long Survey Database Dictionary presents the database structure and defines each field in the 

database files. EPA did not include data from 8 long survey respondents in the database for the 

following reasons: 

� The site was out of business; 

� The site did not use process water; 

� The site was not performing proposed MP&M operations; or 

� The site provided insufficient data and the survey was returned too late to 

enter into the database. 

The Economic, Environmental, and Benefits Analysis of the Proposed Metal 

Products and Machinery Rule, which is located in Section 8.1 of the rulemaking record, DCN 

2000, discusses EPA’s review of Section IV of the detailed survey. 

3.1.2.3 1996 Short Detailed Survey 

EPA distributed the short detailed survey (short survey) in September 1997 to 101 

wastewater-discharging facilities performing proposed MP&M operations. EPA designed this 

survey to gather additional technical and economic information required to develop the MP&M 

effluent limitations guidelines and standards. The short survey is discussed below. 

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3.0 - Data Collection Activities 

1996 Short Survey Recipient Selection and Distribution 

EPA initially sent 100 short surveys in September 1997 and mailed one additional 

survey to a site to replace a short survey that was returned undelivered. EPA assumed the 

undeliverable site to be out of business. The Agency sent the short surveys to randomly selected 

1996 screener respondents who performed operations in one of the 11 industry sectors identified 

in Section 3.1.2 and indicated they discharged less than one million gallons of MP&M process 

wastewater annually. The selection criteria and sampling frame for short survey recipients are 

described in more detail in the Statistical Summary for the Metal Products & Machinery Industry 

Surveys (Section 10.0, DCN 16118). 

EPA established a toll-free telephone helpline and an electronic mail address to 

assist short survey recipients in completing the survey. EPA received helpline calls and 

electronic mail inquiries from approximately 20 short survey recipients. Nonconfidential notes 

from helpline and review follow-up calls are located in Section 5.3.3.1 of the public record for 

this rulemaking. 

1996 Short Survey Mailout Results 

Of the 101 surveys mailed, 82 percent (83 surveys) of the recipients returned 

completed surveys to EPA. A blank copy of the 1996 short survey (Section 3.7.1, DCN 16368) 

and nonconfidential portions of the completed short surveys (Section 5.3.3.1) are located in the 

public record for this rulemaking. Table 3-1 and Figure 3-1 summarize the MP&M survey 

mailout results. 

Information Collected 

The information collected in the 1996 short survey included the identical general 

site and process information and economic information collected in Sections I, II, IV, and V of 

the long detailed survey (see Section 3.1.2.2). To minimize the burden on facilities discharging 

less than one million gallons of process wastewater, EPA did not require these facilities to 

provide the detailed information on proposed MP&M operations or treatment technologies that 

EPA requested in Section III of the long survey. The ICR for this data collection and the survey 

instructions contain further details on the types of information collected and the potential uses of 

the information. 

EPA divided the short survey into the following sections: 

� Section I: General Site Information; 

� Section II: General Process Information; 

� Section IV: Economic Information; and 

� Section V: Voluntary Supplemental Information. 

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3.0 - Data Collection Activities 

Section III, Specific Process Information, consisted of a statement that EPA was not requesting 

this information to reduce burden on sites discharging less than one million gallons of process 

wastewater per year. Table 3-2 summarizes the 1996 short survey information by question 

number. 

1996 Short Survey Data Review and Data Entry 

EPA completed a detailed engineering review of Sections I and II of the short 

survey to evaluate the accuracy of technical information provided by the respondents. During the 

engineering review, EPA coded responses to facilitate entry of technical data into the short 

survey database. The MP&M 1996 Short Survey Database Dictionary identifies the database 

codes developed for this project and is located in Section 5.3.3.2 of the rulemaking record, DCN 

15772. EPA contacted more than 60 short survey respondents, by telephone and letter, to clarify 

incomplete or inconsistent technical information prior to data entry. 

The Agency developed a database for the technical information provided by 

survey respondents. After engineering review and coding, EPA entered data for 75 short surveys 

into the database using a double key-entry and verification procedure. The MP&M 1996 Short 

Survey Database Dictionary presents the database structure and defines each field in the database 

files. EPA did not include data from eight short survey respondents in the database for the 

following reasons: 

� The site was out of business;


� The site did not use process water; or


� The site was not performing proposed MP&M operations.


The Economic, Environmental, and Benefits Analysis of the Proposed Metal 

Products and Machinery Rule, which is located in Section 8.1 of the rulemaking record, DCN 

2000, discusses EPA’s review of Section IV of the short survey. 

3.1.2.4 1996 Municipality Detailed Survey 

EPA distributed the municipality surveys in June 1997 to 150 city and county 

facilities that might operate facilities performing proposed MP&M operations. EPA designed 

this survey to measure the impact of this rule on municipalities and other government entities 

that perform certain maintenance and rebuilding operations (e.g., bus and truck, automobiles). 

Recipient Selection and Distribution 

The Agency sent the municipality survey to 150 city and county facilities 

randomly selected from the Municipality Year Book-1995 based on population and geographic 

location. EPA allocated 60 percent of the sample to municipalities and 40 percent to counties. 

The 60/40 distribution was approximately proportional to their aggregate populations in the 

frame. The Agency divided the municipality sample and the county sample into three size 

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3.0 - Data Collection Activities 

groupings as measured by population. For municipalities, the population groupings were: less 

than 10,000 residents, 10,000 - 50,000 residents, and 50,000 or more residents. For counties, the 

population groupings were: less than 50,000 residents, 50,000 - 150,000 residents, and 150,000 

or more residents. The geographic stratification conformed to the Census definitions of 

Northeast, North Central, South, Pacific, and Mountain states. 

EPA established a toll-free telephone helpline and an electronic mail address to 

assist municipality survey recipients in completing the survey. EPA received helpline calls and 

electronic mail inquiries from more than 50 municipality survey recipients. Notes from helpline 

and review follow-up calls are located in Section 5.3.4.1 of the rulemaking record. 

1996 Municipality Survey Mailout Results 

Of the 150 municipality surveys mailed, three surveys were returned undelivered 

and 135 surveys (90 percent) of the recipients returned completed surveys to EPA. A blank copy 

of the 1996 municipality survey (Section 3.7.1, DCN 16366) and nonconfidential portions of the 

completed municipality surveys (Section 5.3.4.1) are located in the public record for this 

rulemaking. Table 3-1 and Figure 3-1 summarize the MP&M survey mailout results. 

Information Collected 

The 1996 municipality survey collected economic information for the entire 

municipality and site-specific process information for each facility performing proposed MP&M 

operations operated by the municipality. 

EPA divided the municipality detailed survey into the following parts: 

� Part I: Economic and Financial Information; and 

� Part II: General Site-Specific Process Information. 

Table 3-2 summarizes the 1996 municipality survey information by question number. The ICR 

for this data collection (Section 3.5.1, DCN 15766) and the survey instructions (Section 3.7.1, 

DCN 15366) contain further details on the types of information collected and the potential uses 

of the information and are located in the rulemaking record. 

Part I requested information on the site location and contact person, number of 

employees, detailed financial and economic information about the entire municipality, and 

information necessary to determine if the municipality owned and operated facilities performing 

proposed MP&M operations in any of the proposed industrial sectors. 

Part II requested site-specific process information for each facility performing 

proposed MP&M operations owned and operated by the municipality. Question 1 requested the 

site to identify the industry sector and type of activity (manufacturing, rebuilding, or 

maintenance) performed. The remaining questions were identical to Section II of the short 

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3.0 - Data Collection Activities 

detailed survey and requested facility age, process wastewater discharge status and destination, 

wastewater discharge permits and permitting authority, general information about metal types 

processed, products and production levels, water use for unit operations, and wastewater 

discharge from unit operations. The Agency used the process information to evaluate water use 

and discharge practices and sources of pollutants for each proposed MP&M operation. 

1996 Municipality Survey Data Review and Data Entry 

EPA completed a detailed engineering review of Part II of the municipality survey 

to evaluate the accuracy of technical information provided by the respondents. During the 

engineering review, the Agency coded responses to facilitate entry of technical data into the 

municipality survey database. The MP&M 1996 Municipality Survey Database Dictionary 

identifies the database codes developed for this project, and is located in Section 5.3.4.2 of the 

rulemaking record, DCN 15771. EPA contacted more than 50 municipality survey respondents 

by telephone to clarify incomplete or inconsistent technical information prior to data entry. 

The Agency developed a database for the technical information provided by 

survey respondents. After engineering review and coding, EPA entered data from 209 

municipality facilities into the database using a double key-entry and verification procedure. 

This number is greater than the number of respondents because some municipalities had more 

than one facility performing proposed MP&M operations. The MP&M 1996 Municipality 

Survey Database Dictionary presents the database structure and defines each field in the database 

files. 

The Economic, Environmental, and Benefits Analysis of the Proposed Metal 

Products and Machinery Rule, which is located in Section 8.1 of the rulemaking record, DCN 

2000, discusses EPA’s review of Part I of the municipality survey. 

3.1.2.5 1996 Federal Facilities Detailed Survey 

In April 1998, EPA distributed the federal facilities detailed survey (federal 

survey) to the following seven federal agencies: 

� Department of Energy;


� Department of Defense;


� National Aeronautics and Space Administration (NASA);


� Department of Transportation (including the United States Coast Guard);


� Department of Interior;


� Department of Agriculture; and


� United States Postal Service.


EPA used this survey to assess the impact of the MP&M effluent limitations guidelines and 

standards on federal agencies that operate facilities performing proposed MP&M operations. 

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3.0 - Data Collection Activities 

Recipient Selection and Distribution 

There was no specific sampling frame for the federal survey. EPA distributed the 

survey to federal agencies likely to perform industrial operations on metal products or machinery. 

EPA requested representatives of seven federal agencies to voluntarily distribute copies of the 

survey to sites they believed performed proposed MP&M operations. The selection criteria for 

federal survey recipients are described in more detail in the ICR for the 1996 MP&M industry 

surveys. Because the sample was not randomly selected, EPA did not use data from these 

surveys to develop national estimates. 

EPA established a toll-free telephone helpline and an electronic mail address to 

assist federal survey recipients in completing the survey. EPA received helpline calls and 

electronic mail inquiries from approximately 20 federal survey recipients. Nonconfidential notes 

from helpline and review follow-up calls are located in Section 5.3.5.1 of the public record for 

this rulemaking. 

1996 Federal Survey Distribution Results 

The Agency received 51 completed federal surveys, 39 from Department of 

Defense facilities and 12 from NASA facilities. A blank copy of the 1996 federal survey 

(Section 3.7.1, DCN 721) and nonconfidential portions of the completed federal surveys are 

located in Section 5.3.5.1 of the public record for this rulemaking. 

Information Collected 

The information requested in Sections I and III of the 1996 federal survey was 

identical to the long survey (see Section 3.1.2.2). The financial and economic questions in 

Section IV were revised to obtain this information for only the MP&M activities on a federal site. 

The ICR for this data collection and the survey instructions contain further details on the types of 

information collected and the potential uses of the information. Table 3-2 summarizes the 1996 

federal detailed survey information by question number. 

Data Review and Data Entry 

EPA completed a detailed engineering review of Sections I through III of the 

federal survey to evaluate the accuracy of technical information provided by the respondents. 

During the engineering review, the Agency coded responses to facilitate entry of technical data 

into the federal survey database. The MP&M 1996 Federal Survey Database Dictionary 

identifies the database codes developed for this project and is located in Section 5.3.5.2 of the 

rulemaking record, DCN 15991. 

The Agency developed a database for the technical information provided by 

survey respondents. After engineering review and coding, EPA entered data from 44 federal 

surveys into the database using a double key-entry and verification procedure. The Agency did 

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3.0 - Data Collection Activities 

not include data from seven federal survey responses in the database because the sites did not use 

MP&M process water. The MP&M 1996 Federal Survey Database Dictionary presents the 

database structure and defines each field in the database files. 

The Economic, Environmental, and Benefits Analysis of the Proposed Metal 

Products and Machinery Rule, which is located in Section 8.1 of the rulemaking record, DCN 

2000, discusses EPA’s review of Section IV of the federal survey. 

3.1.2.6 1996 POTW Detailed Survey

EPA distributed the POTW survey to 150 sites in November 1997. The Agency 

designed this survey to evaluate benefits associated with the MP&M regulations and to estimate 

possible costs and burden that POTWs might incur in writing and maintaining MP&M permits or 

other control mechanisms. 

Recipient Selection and Distribution 

The Agency sent the POTW survey to 150 POTWs with flow rates greater than 

0.50 million gallons per day. EPA randomly selected the recipients from the 1992 Needs Survey 

Review, Update, and Query System Database. EPA divided the POTW sample into two strata by 

daily flow rates: 0.50 to 2.50 million gallons, and 2.50 million gallons or more. The selection 

criteria and sampling frame for POTW survey recipients are described in more detail in the ICR 

for the 1996 surveys. 

EPA established a toll-free telephone helpline and an electronic mail address to 

assist POTW survey recipients in completing the survey. EPA received helpline calls and 

electronic mail inquiries from approximately 50 POTW survey respondents. Nonconfidential 

notes from helpline and review follow-up calls are located in Section 8.7 of the public record for 

this rulemaking. 

1996 POTW Survey Mailout Results 

Of the 150 POTW surveys mailed, two surveys were returned undelivered and 98 

percent (147) of the recipients returned completed surveys to EPA. A blank copy of the 1996 

POTW survey (Section 3.7.1, DCN 16369) and nonconfidential portions of the completed 

POTW survey (Section 8.7) are located in the public record for this rulemaking. Table 3-1 and 

Figure 3-1 summarize the MP&M survey mailout results. 

Information Collected 

The POTW survey requested data required to estimate benefits and costs 

associated with implementation of the MP&M regulations. The ICR for this data collection and 

the survey instructions contain further details on the types of information collected and the 

potential uses of the information. EPA divided the POTW survey into the following parts: 

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3.0 - Data Collection Activities 

� Part I: Introduction and Basic Information; 

� Part II: Administrative Permitting Costs; and 

� Part III: Sewage Sludge Use or Disposal Costs. 

Part I requested site location and contact information and the total volume of 

wastewater treated at the site. EPA used the wastewater flow information to characterize the size 

of the POTW. 

Part II requested the number of industrial permits written, the cost to write the 

permits, the permitting fee structure, the percentage of industrial dischargers covered by National 

Categorical Standards (i.e., effluent guidelines), and the percentage of permits requiring 

expensive administrative activities. EPA used this information to estimate administrative burden 

and costs. 

Part III requested information on the use or disposal of sewage sludge generated 

by the POTW. EPA required only POTWs that received discharges from facilities performing 

proposed MP&M operations to complete Part III. The sewage sludge information requested 

included the amount generated, use or disposal method, metal levels, use or disposal costs, and 

the percentage of total metal loadings at the POTW from facilities performing proposed MP&M 

operations. The Agency used this information to assess the potential changes in sludge handling 

resulting from the MP&M rule and to estimate economic benefits to the POTW related to sludge 

disposal and reduction in upsets/interference. 

Data Review and Data Entry 

EPA performed a detailed review of the POTW survey to evaluate the accuracy of 

information provided by the respondents. During the review, the Agency coded responses to 

facilitate entry of data into the POTW survey database. The database dictionary for the POTW 

survey identifies the database codes developed for this project, and is located in Section 8.7 of 

the rulemaking record. EPA contacted more than 95 POTW survey respondents by telephone to 

clarify incomplete or inconsistent information prior to data entry. 

The Agency developed a database for the information provided by survey 

respondents. After review and coding, EPA entered data from 147 POTW surveys into the 

database using a double key-entry and verification procedure. The database dictionary presents 

the database structure and defines each field in the database files. 

3.1.3 1997 Iron and Steel Industry Survey Data

As part of its effort to review and revise effluent limitations guidelines and 

standards for the Iron and Steel Point Source Category (40 CFR 420), EPA distributed, reviewed, 

and coded the iron and steel industry detailed and short surveys of 402 iron and steel facilities in 

November 1998. 

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3.0 - Data Collection Activities 

EPA included data from 154 iron and steel surveys in the MP&M survey database. 

EPA used these 154 Iron & Steel surveys to create a new subcategory, Steel Forming and 

Finishing, in the January 2001 proposal. Based on comments to the January 2001 proposal and 

June 2002 NODA, EPA concluded that those operations included in the proposed Steel Forming 

and Finishing Subcategory of the MP&M Point Source Category should remain subject to the 

effluent guidelines and standards at the Iron and Steel Point Source Category (40 CFR 420). See 

Section 6.0 for further discussion of subcategorization. 

As discussed in the June 2002 NODA (67 FR 38752), EPA considered 

establishing a segment of the Steel Forming and Finishing Subcategory for discharges resulting 

from continuous electroplating of flat steel products (e.g., strip, sheet, and plate). EPA examined 

its database for facilities that perform continuous steel electroplating and found that continuous 

electroplaters do not perform operations similar to facilities in the proposed Steel Forming and 

Finishing Subcategory. Rather, continuous electroplaters perform operations included in the 

proposed General Metals Subcategory. Therefore, in evaluating options for the final rule, EPA 

included continuous electroplaters in the proposed General Metals Subcategory. See Section 6.0 

for a detailed discussion of subcategorization. For this reason, EPA incorporated the information 

on these operations reported in 24 iron and steel surveys into the MP&M database. Operations 

on the continuous electroplating lines may include: 

� Acid cleaning;


� Alkaline cleaning;


� Conversion coating (e.g., passivation, surface activation/fluxing);


� Electroplating;


� Rinsing; and


� Sealing.


All 24 sites with electroplating lines processing steel flat-rolled products 

discharge process wastewater. The Agency coded and entered process and wastewater treatment 

information from the 47 lines in the 24 iron and steel surveys into the MP&M cost model. A 

blank copy of the 1997 iron and steel detailed and short surveys and nonconfidential portions of 

the 24 completed iron and steel surveys are located in Sections 5.3.6 and 15.1 of the public 

record for this rulemaking. As discussed in Section 9.0, EPA rejected establishing limitations and 

standards for the proposed General Metals Subcategory. Continuous electroplaters remain subject 

to the Metal Finishing Point Source Category (40 CFR 433), as applicable. 

1997 Iron and Steel Survey Recipient Selection and Distribution 

The Agency consulted with industry trade associations and visited a number of 

sites to develop the survey instruments and to ensure an accurate mailing list. 

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3.0 - Data Collection Activities 

EPA distributed four industry surveys: 

� U.S. EPA Collection of 1997 Iron and Steel Industry Data (detailed 

survey); 

� U.S. EPA Collection of 1997 Iron and Steel Industry Data (Short Form) 

(short survey); 

� U.S. EPA Collection of Iron and Steel Industry Wastewater Treatment 

Capital Cost Data (cost survey); and 

� U.S. EPA Analytical and Production Data Follow-Up to the Collection of 

1997 Iron and Steel Industry Data (analytical and production survey). 

In October 1998, EPA mailed the detailed survey to 176 iron and steel sites and 

the short survey to 223 iron and steel sites. EPA designed the detailed survey for those iron and 

steel sites that perform any iron and steel manufacturing process. Those sites include integrated 

and non-integrated steel mills, as well as sites that were initially identified as stand-alone 

cokemaking plants, stand-alone sinter plants, stand-alone direct-reduced ironmaking plants, 

stand-alone hot forming mills, and stand-alone finishing mills. The short survey is an 

abbreviated version of the detailed survey. It was designed for stand-alone iron and steel sites 

with the exceptions of those that received the detailed survey. EPA mailed the cost survey and 

the analytical and production survey to subsets of the facilities that received the detailed or short 

survey to obtain more detailed information on wastewater treatment system costs, analytical data, 

and facility production. EPA mailed the cost survey to 90 iron and steel sites and the analytical 

and production survey to 38 iron and steel sites. 

EPA mailed the iron and steel industry surveys by mail to facilities that were 

identified from the following sources: 

� Association of Iron and Steel Engineers’ 1997 and 1998 Directories: Iron 

and Steel Plants Volume 1, Plants and Facilities; 

� Iron and Steel Works of the World (11th and 12th editions) directories; 

� Iron and Steel Society’s The Steel Industry of Canada, Mexico, and the 

United States: Plant Locations; 

� Member lists from the following trade associations: 

- American Coke and Coal Chemicals Institute, 

- American Galvanizers Association, 

- American Iron and Steel Institute, 

- American Wire Producers Association, 

- Cold Finished Steel Bar Institute, 

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3.0 - Data Collection Activities 

- Specialty Steel Industry of North America, 

- Steel Manufacturers Association, 

- Steel Tube Institute of North America, and 

- Wire Association International; 

� Dun & Bradstreet Facility Index Database; 

� EPA’s Permit Compliance System (PCS) Database; 

� EPA’s Toxic Release Inventory (TRI) Database; 

� Iron and Steel Society’s Iron and Steelmaker “Roundup” editions; 

� 33 Metalproducing “Roundup” editions (Reference 3-22); 

� 33 Metalproducing “Census of the North American Steel Industry”; and 

� Thomas Register. 

The Agency cross-referenced these sources with one another to develop a list of 

individual sites. Based on these sources, EPA identified 822 candidate facilities to receive 

surveys. To minimize the burden on the respondents, EPA grouped facilities into 12 strata. In 

general, EPA determined the strata based on its understanding of the manufacturing processes at 

each facility. 

Depending on the amount or type of information EPA required for the 

rulemaking, EPA either solicited information from all facilities within a stratum (i.e., a census or 

“certainty” stratum) or selected a random sample of facilities within a stratum (i.e., statistically 

sampled stratum). EPA sent a survey to all facilities in the certainty strata (strata 5 and 8) 

because the Agency determined it was necessary to capture the size, complexity, or uniqueness of 

the steel operations at these sites. EPA also sent surveys to all facilities in strata 1 through 4 (all 

cokemaking sites, integrated steelmaking sites, and sintering and direct-reduced ironmaking 

sites) because of the relatively low number of sites in each stratum and because of the size, 

complexity, and uniqueness of raw material preparation and steel manufacturing operations at 

these sites. The Agency statistically sampled the remaining sites in strata 6, 7, and 9 through 12. 

EPA calculated survey weights for each selected facility based on the facility’s probability of 

selection. If the Agency sent a survey to every facility in a stratum, each selected facility 

represents only itself and has a survey weight of one. For statistically sampled strata, each 

selected facility represents itself and other facilities within that stratum that were not selected to 

receive an industry survey. These facilities have survey weights greater than one. See the 

Development Document for Final Effluent Limitations Guidelines and Standards for the Iron and 

Steel Manufacturing Point Source Category (EPA-821-R-02-004) for more details. 

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3.0 - Data Collection Activities 

Of the 822 candidate facilities, EPA mailed either a detailed survey or a short 

survey to 399 facilities.2 Detailed survey recipients included integrated mills, non-integrated 

mills, stand-alone cokemaking sites, stand-alone sintering sites, stand-alone direct-reduced 

ironmaking sites, stand-alone hot forming sites, and stand-alone finishing sites. Short survey 

recipients included stand-alone cold forming sites, stand-alone pipe and tube sites, stand-alone 

hot dip coating sites, and stand-alone wire sites. 

Once the Agency completed a review of the detailed and short surveys and 

defined the technology options, EPA identified survey respondents who had installed wastewater 

treatment systems in the last 10 years (since 1990) that were similar to the technology options 

and mailed them the cost survey. EPA selected 38 facilities to receive the analytical and 

production survey who had indicated in the detailed or short survey that: (1) they had treatment 

trains similar to the treatment technology options, (2) they had collected analytical data for that 

treatment train, (3) they had a treatment train with a dedicated outfall from which EPA could 

evaluate performance, and (4) they did not add excessive dilution water to the outfall before 

sampling. 

1997 Iron and Steel Survey Information Collected 

The detailed and short surveys were divided into two parts: Part A: Technical 

Information and Part B: Financial and Economic Information. The “Part A” technical questions 

in the detailed survey comprised four sections, with Sections 3 and 4 being combined in the short 

survey, as follows: 

� Section 1: General Site Information; 

� Section 2: Manufacturing Process Information; 

� Section 3: In-Process and End-of-Pipe Wastewater Treatment and 

Pollution Prevention Information; and 

� Section 4: Wastewater Outfall Information. 

The financial and economic information in Part B of the detailed survey also 

comprised four sections, as shown below: 

� Section 1: Site Identification;


� Section 2: Site Financial Information;


� Section 3: Business Entity Financial Information; and


2

Before the surveys were actually mailed, the Agency notified potential survey recipients. One site, randomly 

selected from stratum 12 and notified that it would be receiving a survey, notified the Agency that it was not engaged 

in iron and steel activities. The Agency decided not to mail a survey to that site. Therefore, this site was not 

included in the 399 facilities receiving surveys. 

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3.0 - Data Collection Activities 

� Section 4: Corporate Parent Financial Information. 

Part B of the short survey contained a single section for site identification and 

financial information. More detailed descriptions of financial data collection and analysis are 

included in the Economic Analysis of Final Effluent Limitations Guidelines and Standards for 

the Iron and Steel Manufacturing Point Source Category (EPA 821-R-02-006). 

The detailed survey requested detailed descriptions of all manufacturing processes 

and treatment systems on site. The short survey contained manufacturing process questions for 

only forming and finishing operations. EPA eliminated the cokemaking, ironmaking, and 

steelmaking questions from the short survey because those processes were not applicable to the 

facilities that received the short survey. The Agency also reduced the amount of detail requested 

in the short survey. EPA used the detailed descriptions of hot forming mills from the integrated, 

non-integrated, and stand-alone hot forming mills to make assumptions about industry trends. 

Part A Section 1 requested site contacts and addresses and general information 

regarding manufacturing operations, age, and location. The Agency used this information to 

develop the proposed subcategorization and applicability statements. 

Part A Section 2 requested information on products, types of steel produced, 

production levels, unit operations, chemicals and coatings used, quantity of wastewater 

discharged from unit operations, miscellaneous wastewater sources, flow rates, pollution 

prevention activities, and air pollution control. The Agency used these data to evaluate 

manufacturing processes and wastewater generation, to develop the model productionnormalized flow rates, and to develop regulatory options. EPA also used these data to develop 

the proposed subcategorization and applicability and to estimate compliance costs and pollutant 

removals associated with the regulatory options EPA considered for the final rule. 

Part A Section 3 requested detailed information (including diagrams) on the 

wastewater treatment systems and discharge flow rates, monitoring analytical data, and operating 

and maintenance cost data (including treatment chemical usage). The Agency used these data to 

identify treatment technologies in place, to determine regulatory options, and to estimate 

compliance costs and pollutant removals associated with the regulatory options considered for 

the final rule. 

Part A Section 4 requested permit information, discharge locations, wastewater 

sources to each outfall, flow rates, regulated pollutants and limits, and permit monitoring data. 

EPA used this information to calculate baseline or current loadings for each facility. The Agency 

also used this information to calculate the pollutant loadings associated with the regulatory 

options considered for the final rule. 

The cost survey requested detailed capital cost data on selected wastewater 

treatment systems installed since 1993, including equipment, engineering design, and installation 

costs. (EPA chose 1993 because 1997 was the base year for the detailed and short surveys, and 

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3.0 - Data Collection Activities 

this provided the Agency with a five-year range for collecting cost data on recently installed 

treatment systems.) EPA incorporated these data into a costing methodology and used them to 

determine incremental investment costs and incremental operating and maintenance costs 

associated with the regulatory options considered for the final rule. 

The analytical and production survey requested detailed daily analytical and flow 

rate data for selected sampling points, and monthly production data and operating hours for 

selected manufacturing operations. The Agency used the analytical data collected to estimate 

baseline pollutant loadings and pollutant removals from facilities with treatment in place similar 

to the technology options considered for the final rule, to evaluate the variability associated with 

iron and steel industry discharges, and to establish effluent limitations guidelines and standards. 

The Agency used the production data collected to evaluate the production basis for applying the 

proposal in National Pollutant Discharge Elimination System (NPDES) permits and pretreatment 

control mechanisms. 

1997 Iron and Steel Surveys Data Review and Data Entry 

EPA completed a detailed engineering review of the detailed surveys to evaluate 

the accuracy of technical information provided by the respondents. During the engineering 

review, EPA coded responses to facilitate entry of technical data into the survey database. EPA 

contacted survey respondents, by telephone and letter, to clarify incomplete or inconsistent 

technical information prior to data entry. 

The Agency developed a database for the technical information provided by 

survey respondents. After engineering review and coding, EPA entered data from the surveys 

into the database using a double key-entry and verification procedure. During the engineering 

review, EPA coded responses to facilitate entry of technical data into the survey database. 

3.1.4 Data Submitted by the American Association of Railroads (AAR) 

As noted in the June 2002 NODA (67 FR 38752), EPA conducted another review 

of all railroad line maintenance (RRLM) facilities in the MP&M questionnaire database to 

determine the destination of discharged wastewater (i.e., either directly to surface waters or 

indirectly to POTWs or both) and the applicability of the final rule to discharged wastewaters. 

As a result of this review, EPA determined its questionnaire database did not accurately represent 

direct dischargers in this subcategory. Consequently, EPA used information supplied during the 

comment period by the American Association of Railroads (AAR) as a basis for its analyses and 

conclusions on direct dischargers in this subcategory. 

AAR is a trade association which currently represents all facilities in the RRLM 

Subcategory. As discussed in the NODA (see 67 FR 38755), for each RRLM direct discharging 

facility known to them, AAR provided current permit limits, treatment-in-place, and summarized 

information on each facility’s measured monthly average and daily maximum values. AAR also 

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3.0 - Data Collection Activities 

provided a year’s worth of long-term monitoring data for each facility (see Section 15.1 of the 

rulemaking record for the AAR surveys). 

AAR provided information on 27 facilities. EPA reviewed the information on 

each of these facilities to ensure they were direct dischargers, discharged wastewaters resulting 

from operations subject to this final rule, and discharged "process" wastewaters as defined by the 

final rule. As a result of this review, EPA concluded 18 of the facilities for which AAR provided 

information do not directly discharge wastewaters exclusively from oily operations. Therefore, 

EPA's final database consists of nine direct discharging RRLM facilities. 

3.1.5 National Estimates 

EPA used the data collected in the MP&M and iron and steel industry surveys to: 

(1) calculate national estimates of the number and types of facilities performing proposed 

MP&M operations; (2) develop the industry profile presented in Section 4.0; (3) estimate the 

current pollutant discharges from facilities performing proposed MP&M operations; and (4) 

identify the baseline of treatment in place. The Agency assigned each survey a specific survey 

weight to use as a multiplier for national estimates. 

Sampling Frame 

To produce a mailing list of facilities for the MP&M and the iron and steel 

surveys, EPA developed a sampling frame of the industry. A sampling frame is a list of all 

members (sampling units) of a population, from which a random sample of members will be 

drawn for the survey. Therefore, a sample frame is the basis for the development of a sampling 

plan to select a random sample. A sample frame size (N) is the total number of members in the 

frame. 

EPA mailed MP&M industry surveys to all of the facilities in the sample. Based 

on the survey responses, EPA determined that some facilities were “out of scope” or “ineligible” 

because the regulation would not apply to them. EPA also made a nonrespondent adjustment to 

the weights (see below). 

Calculation of Sample Weights 

The next step in developing national estimates is to calculate the base weights, 

nonresponse adjustments, and the final weights. The base weights and nonresponse adjustments 

reflect the probability of selection for each facility and adjustments for facility-level 

nonresponses, respectively. Weighting the data allows inferences to be made about all eligible 

facilities, not just those included in the sample, but also those not included in the sample or those 

that did not respond to the survey. Also, the weighted estimates have a smaller variance than 

unweighted estimates. In its analysis, EPA applied sample weights to survey data. 

3-33

3.0 - Data Collection Activities 

Calculation of National Estimates 

For each characteristic of interest (e.g., number of sites using a particular unit 

operation or annual discharge flow from a particular unit operation), EPA estimated totals for the 

entire U.S. industry performing proposed MP&M operations (i.e., national estimates). Each 

national estimate, Yst, was calculated as: 

(3-1) 

where: 

h = Survey where h = 1,2, ... T; 

T = Total number of surveys; 

FINALWTh = Final weight for survey h; and 

yhi = ith value from the sample. 

The development of survey weights and national estimates for the MP&M surveys are discussed 

in greater detail in the Statistical Summary for the Metal Products & Machinery Industry Surveys 

(Section 10.0, DCN 16118) and DCNs 36086 and 36087, Section 19.5. 

Each national estimate for the entire U.S. iron and steel industry, �st, was 

calculated as: 

(3-2) 

where: 

h = Stratum and h=1,2,...12 since there are 12 strata; 

FINALWTh = Final weight for the stratum h; and 

yih = Ith value from the sample in stratum h. 

The development of the iron and steel survey weights and national estimates are discussed in 

greater detail in the Development Document for Final Effluent Limitations Guidelines and 

Standards for the Iron and Steel Manufacturing Point Source Category (EPA-821-R-02-004). 

3.2 Site Visits 

The Agency visited 234 facilities performing proposed MP&M operations and 

iron and steel sites between 1986 and 2001 to collect information about proposed MP&M 

operations, water use practices, pollution prevention and treatment technologies, and waste 

disposal methods, and to evaluate sites for potential inclusion in the MP&M sampling program 

(described in Section 3.3). In general, the Agency visited sites to encompass the range of sectors, 

unit operations, and wastewater treatment technologies within the industry (discussed in Section 

3-34

3.0 - Data Collection Activities 

3.2.1). Table 3-3 lists the number of sites visited within each industrial sector. The total number 

of site visits presented in this table exceeds 234 because some sites had operations in more than 

one sector. Figure 3-2 presents the number of facilities visited and sampled by industrial sector. 

Table 3-3 and Figure 3-2 also include site visits initially conducted as part of the iron and steel 

rulemaking, the results of which were incorporated into the MP&M rulemaking. 

Table 3-3 

Number of Sites Visited Within Each Proposed Industrial Sector 

Industrial Sectors 

Total 

Number of 

Sites Visited Industrial Sectors 

Total 

Number of 

Sites Visited 

Aerospace 

Aircraft 

Bus and Truck 

Electronic Equipment 

Hardware 

Household Equipment 

Instrument 

Job Shops 

Miscellaneous Metal Products 

Mobile Industrial Equipment 

Motor Vehicle 

13 

32 

8 

23 

15 

4 

4 

25 

0 

7 

20 

Office Machines 

Ordnance 

Precious Metals and Jewelry 

Printed Wiring Boards 

Railroad 

Ships and Boats 

Stationary Industrial Equipment 

Steel Continuous Electroplatinga 

Steel Forming and Finishing: Wire 

Drawinga 

5 

15 

2 

17 

10 

7 

14 

15 

4 

Source: MP&M and Iron and Steel Site Visits.
 a

The number of sites visited is listed separately for steel forming and finishing and steel continuous electroplating


sites instead of by industrial sector.


3.2.1 Criteria for Site Selection 

The Agency selected sites for visits based on information contained in the MP&M 

and iron and steel surveys. The Agency also contacted regional EPA personnel, state 

environmental agency 

3-35

3-36


Industrial Sector 

Steel Forming and Finishing - Wire Draw ing


Steel Continuous Electroplating


Stationary Industrial Equipment


Ships and Boats


Railroad


Printed Wiring Boards


Precious Metals and Jew elry


Ordnance


Office Machines


Motor Vehicles


Mobile Industrial Equipment


Miscellaneous Metal Products


Job Shop Metal Finishing


Instruments


Household Equipment


Hardw are


Electronic Equipment


Bus and Truck


Aircraft


Aerospace
 13 2 

9 

8 4 

23 4 

15 4 

4

2 

4 

2 

25 10 

NA 

7 

2 

20 9 5 

2 

15 3 

2 (both) 

17 5 

10 4 

7 3 

14 4 

6 

2 

4 2 

Number of SiteNumber of Site

0 5 10 15 20 25 

Number of Sites 

Figure 3-2. Number of Facilities Performing Proposed MP&M Operations Visited and Sampled by I
3.0 - Data Collection Activities 

personnel, and local pretreatment coordinators to identify facilities performing proposed MP&M 

operations believed to be operating in-process source reduction and recycling technologies and/or 

well-operated end-of-pipe wastewater treatment technologies. For visits to iron and steel sites 

prior to receipt of any completed survey, EPA used information collected from the sources used 

to develop the iron and steel survey receipt list (discussed in Section 3.1.3). 

The Agency used the following four general criteria to select sites that 

encompassed the range of sectors and unit operations within the industry: 

1.	 The site performed proposed MP&M operations in one of the industrial 

sectors. To assess the variation of unit operations and water-use practices 

across sectors, the Agency visited sites in 18 industrial sectors. 

2.	 The site performed proposed MP&M operations that needed to be 

characterized for development of the regulation. 

3.	 The site had water-use practices that were believed to be representative of 

the best sites within an industrial sector. 

4.	 The site operated in-process source reduction, recycling, or end-of-pipe 

treatment technologies EPA was evaluating in developing the MP&M 

technology options. 

The Agency also visited sites of various sizes. EPA visited sites with wastewater 

flows ranging from less than 200 gallons per day (gpd) to more than 1,000,000 gpd. 

EPA selected iron and steel sites to visit based on the type of site (steel forming 

and finishing, integrated, non-integrated), the manufacturing operations at each facility, the type 

of steel produced (carbon, alloy, stainless), and the wastewater treatment operations. The 

Agency wanted to visit all types of iron and steel manufacturing operations as well as all types of 

wastewater treatment operations, including recently installed treatment systems. After EPA 

evaluated the completed surveys and in response to comments received on the proposed rule, the 

Agency used information provided by the sites to select additional iron and steel sites to visit. 

Site-specific selection criteria are discussed in site visit reports (SVRs) prepared 

for each site visited by EPA. The SVRs are located in Sections 5.1 and 15.2 of the rulemaking 

record. 

3-37

3.0 - Data Collection Activities 

3.2.2 Information Collected 

During the site visits, EPA collected the following types of information: 

� Types of unit operations performed at the site and the types of metals 

processed through these operations; 

� Purpose of unit operations performed and purpose of any process water 

and chemical additions used by the unit operations; 

� Types and disposition of wastewater generated at the site; 

� Types of in-process source reduction and recycling technologies 

performed at the site; 

� Cross-media impacts of in-process source reduction and recycling 

technologies; 

� Types of end-of-pipe treatment technologies performed at the site; and 

� Logistical information required for sampling. 

This information is documented in the SVRs for each site. Nonconfidential SVRs can be found 

in the MP&M rulemaking record (see Sections 5.1 and 15.2). 

EPA MP&M Sampling Program 

The Agency conducted sampling episodes at 84 sites between 1986 and 2001 to 

obtain data on the characteristics of wastewater and solid wastes. In addition, EPA performed 

sampling episodes to assess the following: (1) the loading of pollutants to surface waters and 

POTWs from facilities performing proposed MP&M operations; (2) the effectiveness of 

technologies designed to reduce and remove pollutants from wastewater; and (3) the variation of 

wastewater characteristics across unit operations, metal types processed in each unit operation, 

and sectors. Table 3-4 indicates the number of sites sampled within each industrial sector. The 

number of sampled sites presented in the table does not equal 84 because EPA conducted 

multiple sampling episodes at some sites, and some sites had operations in multiple sectors. 

Figure 3-2 presents the number of sites visited and sampled by industrial sector. Table 3-4 and 

Figure 3-2 also include sites initially sampled as part of the iron and steel rulemaking, the results 

of which were incorporated into the MP&M rulemaking. 

3-38


3.3 
3.0 - Data Collection Activities 

Table 3-4


Number of Sites Sampled Within Each Proposed Industrial


Industrial Sectors 

Total Number 

of Sites 

Sampled Industrial Sectors 

Total Number 

of Sites 

Sampled 

Aerospace 

Aircraft 

Bus and Truck 

Electronic Equipment 

Hardware 

Household Equipment 

Instruments 

Job Shops 

Miscellaneous Metal Products 

Mobile Industrial Equipment 

Motor Vehicle 

2 

9 

4 

4 

4 

2 

2 

10 

0 

2 

9 

Office Machines 

Ordnance 

Precious Metals and Jewelry 

Printed Wiring Boards 

Railroad 

Ships and Boats 

Stationary Industrial Equipment 

Steel Continuous Electroplatinga 

Steel Forming and Finishing: Wire 

Drawinga 

2 

3 

2 

5 

4 

3 

4 

5 

2 

Source: MP&M and Iron and Steel Sampling Episodes.
 a

The number of sites sampled is listed separately for steel forming and finishing and steel continuous electroplater


sites instead of by industrial sector.


3.3.1 Criteria for Site Selection 

The Agency used information collected during MP&M site visits to identify 

candidate sites for sampling. The Agency used the following general criteria to select sites for 

sampling: 

� The site performed proposed MP&M operations EPA was evaluating for 

the MP&M regulation; 

� The site processed metals through proposed MP&M operations for which 

the metal type/unit operation combination needed to be characterized for 

the sampling database; 

� The site performed in-process source reduction, recycling, or end-of-pipe 

treatment technologies that EPA was evaluating for technology option 

development; and 

� The site performed unit operations in a sector that EPA was evaluating for 

the MP&M regulation. 

The Agency also sampled at sites of various sizes, with wastewater flows ranging from less than 

200 gpd to more than 1,000,000 gpd. 

3-39

3.0 - Data Collection Activities 

EPA selected iron and steel sampling sites using the following criteria: 

� The site performed operations either currently regulated under 40 CFR 420 

or identified in the Preliminary Study or otherwise identified as iron and 

steel operations; 

� The site performed high-rate recycling, in-process treatment, or end-ofpipe treatment operations that EPA believed may represent potential 

model pollutant control technology; and 

� The site’s compliance monitoring data indicated that it was among the 

better performing pollutant control systems in the industry, based on 

comparisons of monitoring data from other facilities with limits from the 

1982 regulation in their permits. 

In response to comments received on the proposed rule, EPA conducted 

wastewater sampling at four additional sites between November 2000 and April 2001. EPA 

selected these additional sites for the following reasons: 

� As a collaborative effort between the American Iron and Steel Institute and 

EPA, to supplement the 1997/1998 sampling results by further 

characterizing raw sinter plant wastewater, specifically the amount of 

dioxins and furans generated by this industry, and to evaluate wastewater 

treatment system performance; and 

� To further characterize untreated wastewater generated by continuous 

casting and hot forming operations at non-integrated steel mills. 

After it selected a site for sampling, the Agency prepared a detailed sampling and 

analysis plan (SAP), based on the information contained in the SVR and follow-up 

correspondence with the site. EPA prepared the SAPs to ensure samples collected would be 

representative of the sampled waste streams. The SAPs contained the following types of 

information: site-specific selection criteria for sampling; information about site operations; 

sampling point locations and sample collection, preservation, and transportation procedures; site 

contacts; and sampling schedules. 

3.3.2 Information Collected 

In addition to wastewater and solid waste samples, the Agency collected the 

following types of information during each sampling episode: 

� Dates and times of sample collection; 

� Flow data corresponding to each sample; 

3-40

3.0 - Data Collection Activities 

� Production data corresponding to each sample of wastewater from 

proposed MP&M operations; 

� Design and operating parameters for source reduction, recycling, and 

treatment technologies characterized during sampling; 

� Information about site operations that had changed since the site visit or 

that were not included in the SVR; and 

� Temperature and pH of the sampled waste streams. 

EPA documented all data collected during sampling episodes in the sampling 

episode report (SER) for each sampled site. SERs are located in Sections 5.2 and 15.3 of the 

rulemaking record. 

3.3.3 Sample Collection and Analysis 

The Agency collected, preserved, and transported all samples according to EPA 

protocols as specified in EPA’s Sampling and Analysis Procedures for Screening of Industrial 

Effluents for Priority Pollutants (1) (Section 4.2, DCN 17334) and the MP&M Quality 

Assurance Project Plan (QAPP) (Section 4.4, DCN 17366). These documents are located in the 

rulemaking record. Appendix B presents the analytical methods and baseline values. 

In general, EPA collected composite samples from wastewater streams with 

compositions that the Agency expected to vary over the course of a production period (e.g., 

overflowing rinse waters, wastewater from continuous recycling and treatment systems). The 

Agency collected grab samples from unit operation baths or rinses that the facility did not 

continuously discharge and that the Agency did not expect to vary over the course of a 

production period. EPA also collected composite samples of wastewater treatment sludge at 11 

facilities. EPA collected the required types of quality control samples as described in the MP&M 

QAPP, such as blanks and duplicate samples, to verify the precision and accuracy of sample 

analyses. 

The Agency shipped samples via overnight air transportation to EPA-approved 

laboratories, where the samples were analyzed for metal and organic pollutants and additional 

parameters (including several water quality parameters). EPA analyzed metal pollutants using 

EPA Method 1620 (2), volatile organic pollutants using EPA Method 1624 (3), and semivolatile 

organic pollutants using EPA Method 1625 (4). Tables 3-5 and 3-6 list the metal and organic 

pollutants, respectively, analyzed using these methods. Table 3-5 also lists additional metal 

pollutants that EPA analyzed in the MP&M sampling program, but, as specified by EPA Method 

1620, were not subject to the rigorous quality assurance/quality control procedures established by 

the QAPP. 

3-41

3.0 - Data Collection Activities 

Table 3-5 

Metal Constituents Measured Under the MP&M Sampling Program 

(EPA Method 1620) 

Metal Constituents 

ALUMINUM 

ANTIMONY 

ARSENIC 

BARIUM 

BERYLLIUM 

BORON 

CADMIUM 

CALCIUM 

CHROMIUM 

COBALT 

COPPER 

IRON 

LEAD 

MAGNESIUM 

MANGANESE 

MERCURY 

MOLYBDENUM 

NICKEL 

SELENIUM 

SILVER 

SODIUM 

THALLIUM 

TIN 

TITANIUM 

VANADIUM 

YTTRIUM 

ZINC 

Additional Metal Constituentsa Not Subject to Rigorous QA/QC Procedures Per Method 1620 

BISMUTH 

CERIUM 

DYSPROSIUM 

ERBIUM 

EUROPIUM 

GADOLINIUM 

GALLIUM 

GERMANIUM 

GOLD 

HAFNIUM 

HOLMIUM 

INDIUM 

IODINE 

IRIDIUM 

LANTHANUM 

LITHIUM 

LUTETIUM 

NEODYMIUM 

NIOBIUM 

OSMIUM 

PALLADIUM 

PHOSPHORUS 

PLATINUM 

POTASSIUM 

PRASEODYMIUM 

RHENIUM 

RHODIUM 

RUTHENIUM 

SAMARIUM 

SCANDIUM 

SILICON 

STRONTIUM 

SULFUR 

TANTALUM 

TELLURIUM 

TERBIUM 

THORIUM 

THULIUM 

TUNGSTEN 

URANIUM 

YTTERBIUM 

ZIRCONIUM 

Source: EPA Method 1620. 
 a

Analyses for these metals were used primarily for screening purposes


3-42

3.0 - Data Collection Activities 

Table 3-6 

Organic Constituents Measured Under the MP&M Sampling Program 

(EPA Methods 1624 and 1625) 

Volatile Organic Constituents (EPA Method 1624) 

ACRYLONITRILE 

BENZENE 

BROMODICHLOROMETHANE 

BROMOMETHANE 

CARBON DISULFIDE 

CHLOROACETONITRILE 

CHLOROBENZENE 

CHLOROETHANE 

CHLOROFORM 

CHLOROMETHANE 

CIS-1,3-DICHLOROPROPENE 

CROTONALDEHYDE 

DIBROMOCHLOROMETHANE 

DIBROMOMETHANE 

DIETHYL ETHER 

ETHYL CYANIDE 

ETHYL METHACRYLATE 

ETHYLBENZENE 

IODOMETHANE 

ISOBUTYL ALCOHOL 

M-XYLENE 

METHYL METHACRYLATE 

METHYLENE CHLORIDE 

O+P-XYLENE 

TETRACHLOROETHENE 

TETRACHLOROMETHANE 

TOLUENE 

TRANS-1,2-DICHLOROETHENE 

TRANS-1,3-DICHLOROPROPENE 

TRANS-1,4-DICHLORO-2-BUTENE 

TRIBROMOMETHANE 

TRICHLOROETHENE 

TRICHLOROFLUOROMETHANE 

VINYL ACETATE 

VINYL CHLORIDE 

1,1-DICHLOROETHANE 

1,1-DICHLOROETHENE 

1,1,1-TRICHLOROETHANE 

1,1,1,2-TETRACHLOROETHANE 

1,1,2-TRICHLOROETHANE 

1,1,2,2-TETRACHLOROETHANE 

1,2-DIBROMOETHANE 

1,2-DICHLOROETHANE 

1,2-DICHLOROPROPANE 

1,2,3-TRICHLOROPROPANE 

1,3-BUTADIENE, 2-CHLORO 

1,3-DICHLOROPROPANE 

1,4-DIOXANE 

2-BUTANONE 

2-CHLOROETHYL VINYL ETHER 

2-HEXANONE 

2-PROPANONE 

2-PROPEN-1-OL 

2-PROPENAL 

2-PROPENENITRILE, 2-METHYL3-CHLOROPROPENE 

4-METHYL-2-PENTANONE 

ACROLEIN 

3-43

3.0 - Data Collection Activities 

Table 3-6 (Continued) 

Semivolatile Organic Constituents (EPA Method 1625) 

ACENAPHTHENE 

ACENAPHTHYLENE 

ACETOPHENONE 

ALPHA-TERPINEOL 

ANILINE 

ANILINE, 2,4,5-TRIMETHYLANTHRACENE 

ARAMITE 

BENZANTHRONE 

BENZENETHIOL 

BENZIDINE 

BIS(2-CHLOROETHOXY)METHANE 

BIS(2-CHLOROETHYL) ETHER 

BIS(2-CHLOROISOPROPYL) ETHER 

BIS(2-ETHYLHEXYL) PHTHALATE 

BUTYL BENZYL PHTHALATE 

CARBAZOLE 

CHRYSENE 

CIODRIN 

CROTOXYPHOS 

DI-N-BUTYL PHTHALATE 

DI-N-OCTYL PHTHALATE 

DI-N-PROPYLNITROSAMINE 

DIBENZO(A,H)ANTHRACENE 

DIBENZOFURAN 

DIBENZOTHIOPHENE 

DIETHYL PHTHALATE 

DIMETHYL PHTHALATE 

DIMETHYL SULFONE 

DIPHENYL ETHER 

DIPHENYLAMINE 

DIPHENYLDISULFIDE 

ETHANE, PENTACHLOROETHYL METHANESULFONATE 

ETHYLENETHIOUREA 

FLUORANTHENE 

FLUORENE 

HEXACHLOROBENZENE 

HEXACHLOROBUTADIENE 

HEXACHLOROCYCLOPENTADIENE 

HEXACHLOROETHANE 

HEXACHLOROPROPENE 

HEXANOIC ACID 

INDENO(1,2,3-CD)PYRENE 

BENZO(A)ANTHRACENE 

BENZO(A)PYRENE 

BENZO(B)FLUORANTHENE 

BENZO(GHI)PERYLENE 

BENZO(K)FLUORANTHENE 

BENZOIC ACID 

BENZONITRILE, 3,5-DIBROMO-4-HYDROXYBENZYL ALCOHOL 

BETA-NAPHTHYLAMINE 

BIPHENYL 

BIPHENYL, 4-NITRO 

N-EICOSANE 

N-HEXACOSANE 

N-HEXADECANE 

N-NITROSODI-N-BUTYLAMINE 

N-NITROSODIETHYLAMINE 

N-NITROSODIMETHYLAMINE 

N-NITROSODIPHENYLAMINE 

N-NITROSOMETHYLETHYLAMINE 

N-NITROSOMETHYLPHENYLAMINE 

N-NITROSOMORPHOLINE 

N-NITROSOPIPERIDINE 

N-OCTACOSANE 

N-OCTADECANE 

N-TETRACOSANE 

N-TETRADECANE 

N-TRIACONTANE 

N,N-DIMETHYLFORMAMIDE 

NAPHTHALENE 

NITROBENZENE 

O-ANISIDINE 

O-CRESOL 

O-TOLUIDINE 

O-TOLUIDINE, 5-CHLOROP-CHLOROANILINE 

P-CRESOL 

P-CYMENE 

P-DIMETHYLAMINOAZOBENZENE 

P-NITROANILINE 

PENTACHLOROBENZENE 

PENTACHLOROPHENOL 

PENTAMETHYLBENZENE 

PERYLENE 

PHENACETIN 

3-44

3.0 - Data Collection Activities 

Table 3-6 (Continued) 

Semivolatile Organic Constituents (EPA Method 1625) 

ISOPHORONE 

ISOSAFROLE 

LONGIFOLENE 

MALACHITE GREEN 

MESTRANOL 

METHAPYRILENE 

METHYL METHANESULFONATE 

N-DECANE 

N-DOCOSANE 

N-DODECANE 

STYRENE 

THIANAPHTHENE 

THIOACETAMIDE 

THIOXANTHE-9-ONE 

TOLUENE, 2,4-DIAMINOTRIPHENYLENE 

TRIPROPYLENEGLYCOL METHYL ETHER 

1-BROMO-2-CHLOROBENZENE 

1-BROMO-3-CHLOROBENZENE 

1-CHLORO-3-NITROBENZENE 

1-METHYLFLUORENE 

1-METHYLPHENANTHRENE 

1-NAPHTHYLAMINE 

1-PHENYLNAPHTHALENE 

1,2-DIBROMO-3-CHLOROPROPANE 

1,2-DICHLOROBENZENE 

1,2-DIPHENYLHYDRAZINE 

1,2,3-TRICHLOROBENZENE 

1,2,3-TRIMETHOXYBENZENE 

1,2,4-TRICHLOROBENZENE 

1,2,4,5-TETRACHLOROBENZENE 

1,2:3,4-DIEPOXYBUTANE 

1,3-DICHLORO-2-PROPANOL 

1,3-DICHLOROBENZENE 

1,3,5-TRITHIANE 

1,4-DICHLOROBENZENE 

1,4-DINITROBENZENE 

1,4-NAPHTHOQUINONE 

1,5-NAPHTHALENEDIAMINE 

2-(METHYLTHIO)BENZOTHIAZOLE 

2-CHLORONAPHTHALENE 

2-CHLOROPHENOL 

2-ISOPROPYLNAPHTHALENE 

2-METHYLBENZOTHIOAZOLE 

2-METHYLNAPHTHALENE 

PHENANTHRENE 

PHENOL 

PHENOL, 2-METHYL-4,6-DINITROPHENOTHIAZINE 

PRONAMIDE 

PYRENE 

PYRIDINE 

RESORCINOL 

SAFROLE 

SQUALENE 

2-NITROANILINE 

2-NITROPHENOL 

2-PHENYLNAPHTHALENE 

2-PICOLINE 

2,3-BENZOFLUORENE 

2,3-DICHLOROANILINE 

2,3-DICHLORONITROBENZENE 

2,3,4,6-TETRACHLOROPHENOL 

2,3,6-TRICHLOROPHENOL 

2,4 -DICHLOROPHENOL 

2,4-DIMETHYLPHENOL 

2,4-DINITROPHENOL 

2,4-DINITROTOLUENE 

2,4,5-TRICHLOROPHENOL 

2,4,6-TRICHLOROPHENOL 

2,6-DI-TERT-BUTYL-P-BENZOQUINONE 

2,6-DICHLORO-4-NITROANILINE 

2,6-DICHLOROPHENOL 

2,6-DINITROTOLUENE 

3-METHYLCHOLANTHRENE 

3-NITROANILINE 

3,3'-DICHLOROBENZIDINE 

3,3'-DIMETHOXYBENZIDINE 

3,6-DIMETHYLPHENANTHRENE 

4-AMINOBIPHENYL 

4-BROMOPHENYL PHENYL ETHER 

4-CHLORO-2-NITROANILINE 

4-CHLORO-3-METHYLPHENOL 

4-CHLOROPHENYL PHENYL ETHER 

4-NITROPHENOL 

4,4'-METHYLENEBIS(2-CHLOROANILINE) 

4,5-METHYLENE PHENANTHRENE 

5-NITRO-O-TOLUIDINE 

7,12-DIMETHYLBENZ(A)ANTHRACENE 

N-NITRODOSI-N-PROPYLAMINE 

Source: EPA Methods 1624 and 1625. 

3-45

3.0 - Data Collection Activities 

The Agency used these metals analyses for screening purposes and did not select the metals for 

regulation in this rulemaking (see Section 7.0). EPA analyzed additional parameters, including 

several water quality parameters, using analytical methods contained in EPA’s Methods for 

Chemical Analysis of Water and Wastes (5). Table 3-7 lists these parameters, along with the 

method and technique used to analyze for each parameter. Method descriptions are included in 

the MP&M QAPP. The specific parameters measured in each sample are listed in the SER for 

each sampling episode. 

Quality control measures used in performing all analyses complied with the 

guidelines specified in the analytical methods and in the MP&M QAPP. EPA reviewed all 

analytical data to ensure that these measures were followed and that the resulting data were 

within the QAPP-specified acceptance criteria for accuracy and precision. 

As discussed previously, upon receipt and review of the analytical data for each 

site, EPA prepared an SER to document the data collected during sampling, the analytical results, 

and the technical analyses of the results. The SAPs and correspondence with site personnel are 

included as appendices to the SERs. 

Other Sampling Data 

The Association of American Railroads (AAR), the Hampton Roads Sanitation 

District (HRSD), the Los Angeles County Sanitation Districts (LACSD), and the Association 

Connecting Electronic Industries (IPC) proposed potential sampling sites to the Agency, and 

EPA visited these sites to identify candidates for sampling. After conducting site visits, EPA 

selected six sites for sampling episodes. 

EPA selected the six sites to characterize end-of-pipe treatment technologies in 

metal finishing and aircraft parts job shops and the railroad and shipbuilding industrial sectors. 

AAR sampled a railroad line maintenance that used dissolved air flotation (DAF) to treat MP&M 

process wastewater. HRSD sampled a ship manufacturer that uses DAF, chemical precipitation, 

and cyanide destruction to treat process wastewater. LACSD sampled two metal finishing job 

shops and one aircraft parts manufacturing job shop. EPA selected the LACSD sites to provide 

data for cyanide treatment and also conducted effluent variability sampling at one of the metal 

finishing job shops. The IPC site is a printed wiring board facility that uses chemical 

precipitation with chelation breaking, cyanide destruction and batch treatment to treat process 

wastewater. 

EPA prepared detailed SAPs based on the information collected during the six site 

visits, and AAR, HRSD and LACSD collected the wastewater samples. EPA also prepared the 

sampling episode reports. In addition to the wastewater samples, sampling personnel 

documented the collection date and time, sample flow data, treatment unit design and operating 

parameters, and temperature and pH of the sampled waste streams. All data collected during 

sampling episodes are documented in the SER for each sampled site, which are located in the 

3-46


3.4 
3.0 - Data Collection Activities 

Table 3-7


Additional Parameters Measured Under the MP&M Sampling Program


Parameter EPA Method 

Acidity 305.1 

Alkalinity 310.1 

Ammonia as Nitrogen 350.1 

BOD 5-Day (Carbonaceous) 405.1 

Chemical Oxygen Demand (COD) 410.1 

410.2 

Chloride 325.3 

Chromium, Hexavalent 218.4 

Cyanide, Amenable 335.1 

Cyanide, Total 335.2 

Cyanide, Weak Acid Dissociable (WAD) 1677 

Fluoride 340.2 

Nitrogen, Total Kjeldahl 351.2 

Oil and Grease 413.2 

Oil and Grease (as HEM) 1664 

pH 150.1 

Phenolics, Total Recoverable 420.2 

Phosphorus, Total 365.4 

Sulfate 375.4 

Sulfide, Total 376.1, 376.2 

Total Dissolved Solids (TDS) 160.1 

Total Organic Carbon (TOC) 415.1 

Total Petroleum Hydrocarbons (as SGT-HEM) 1664 

Total Suspended Solids (TSS) 160.2 

Ziram (zinc dimethyldithiocarbamate) 630.1 

Source: EPA Methods for Chemical Analysis of Water and Wastes (5). 

3-47

3.0 - Data Collection Activities 

MP&M rulemaking record (see Sections 5.2 and 15.3). EPA combined these data with data 

collected from the MP&M sampling program. For a discussion of sample collection and the 

sampling protocols for the IPC site, see the SER (DCN 16684) in Section 15.3.7 of the MP&M 

rulemaking record. 

AAR, HRSD, and LACSD collected, preserved, and transported all samples 

according to EPA protocols as specified in EPA’s Sampling and Analysis Procedures for 

Screening of Industrial Effluents for Priority Pollutants (Section 4.2, DCN 17334) and the 

MP&M QAPP. Procedures for shipping and analysis of the samples were similar to those 

discussed in Section 3.3 with the exception that some samples were shipped directly to internal 

sanitation district laboratories for analysis. Pollutant parameters and analytical methods were 

agreed upon by EPA, AAR, HRSD, and LACSD and were treated as equivalent to those in the 

EPA MP&M sampling program. 

Other Industry-Supplied Data 

EPA evaluated other industry data in developing the MP&M effluent guidelines. 

The data sources reviewed included: 

� Public comments to the May 1995 Proposal, January 2001 proposal, and 

June 2002 NODA; 

� The Metal Finishing F006 Benchmark Study (6); 

� Data supporting the Final Rule for the F006 Accumulation Time 

Extension (65 FR 12377, March 8, 2000); 

� Data provided by the Aluminum Anodizing Council (AAC), the American 

Wire Producers Association (AWPA), and the Aerospace Association; and 

� Surveys provided by the North Carolina Pretreatment Consortium. 

EPA also reviewed data from stormwater pollution prevention plans provided by 

several shipbuilding sites, dry dock data from a shipbuilding site, and data from periodic 

compliance monitoring reports/discharge monitoring reports for 19 sites that were part of the 

Agency’s wastewater sampling program. 

The Agency included data submitted with comments on the 1995 MP&M 

Proposed Rule, the 2001 MP&M Proposed Rule, or the 2002 MP&M NODA in the 

establishment of effluent limitations and standards if they met the following criteria: 

� Measurements of daily effluent concentration were provided; 

3-48


3.5 
3.0 - Data Collection Activities 

� Data represented effluent from a treatment system equivalent to EPA’s 

BAT options; 

� Samples represented fully treated effluent (as defined by Options 2, 6, or 

10 as appropriate); and 

� Treated pollutants were identified and/or unit operations contributing 

pollutants were described. 

In addition, the North Carolina Pretreatment Consortium conducted a survey of 

POTWs in that state. EPA evaluated the results of these surveys and used the results as 

appropriate to verify and supplement information from the previous MP&M POTW survey on 

loadings, number of facilities performing proposed MP&M operations served, and administrative 

costs. The results of EPA’s analysis of this data is in the Comment Response Document, Issue 

Codes 4 and 20G. The AMSA and North Carolina Pretreatment Consortium surveys can be 

found in Section 17.6 of the rulemaking record. 

Other Data Sources 

In developing the MP&M effluent guidelines, EPA evaluated the following 

existing data sources: 

1.	 EPA Engineering and Analysis Division (EAD) databases from 

development of effluent guidelines for miscellaneous metals industries; 

2.	 The Fate of Priority Pollutants in Publicly Owned Treatment Works (50 

POTW Study) database; 

3.	 The Office of Research and Development (ORD) National Risk 

Management and Research Laboratory (NRMRL) treatability database; 

4. The Domestic Sewage Study; 

5. The Toxics Release Inventory (TRI) database; and 

6.	 Discharge Monitoring Reports (DMR) from EPA’s Permit Compliance 

System (PCS). 

These data sources and their uses for the development of the MP&M effluent guidelines are 

discussed below. 

3-49


3.6 
3.0 - Data Collection Activities 

3.6.1 EPA/EAD Databases 

As discussed in Section 2.0, EPA had earlier promulgated effluent guidelines for 

13 metals industries. In developing these past effluent guidelines, EPA collected wastewater 

samples to characterize the unit operations and treatment systems at sites in these industries. 

Facilities performing proposed MP&M operations operate many of the same or similar sampled 

unit operations and treatment systems; therefore, EPA evaluated these data for transfer to the 

MP&M effluent guidelines development effort. 

For the pollutant loading and wastewater characterization efforts, EPA reviewed 

the data collected for unit operations performed at both facilities performing proposed MP&M 

operations and at sites in the other metals industries. EPA reviewed the Technical Development 

Documents (TDDs), sampling episode reports, and supporting rulemaking record materials for 

the other metals industries to identify available data. EPA used these data for the preliminary 

assessment of the industry, but did not use these data to estimate pollutant loadings because EPA 

obtained sufficient data from the MP&M sampling program to characterize the proposed MP&M 

operations. 

For the MP&M technology effectiveness assessment effort, EPA reviewed 

sampling data collected to characterize treatment systems for the development of effluent 

guidelines for miscellaneous metals industries. For several previous effluent guidelines, EPA 

used treatment data from metals industries to develop the Combined Metals Database (CMDB), 

which served as the basis for developing limits for these industries. EPA also developed a 

separate database used as the basis for limits for the Metal Finishing category. EPA used the 

CMDB and Metal Finishing data as a guide in identifying well-designed and well-operated 

treatment systems. EPA did not use these data in developing the MP&M technology 

effectiveness concentrations, since the Agency collected sufficient data from facilities performing 

proposed MP&M operations to develop technology effectiveness concentrations. 

3.6.2 Fate of Priority Pollutants in Publicly Owned Treatment Works Database 

In September 1982, EPA published the Fate of Priority Pollutants in Publicly 

Owned Treatment Works (7), referred to as the 50-POTW Study. The purpose of this study was 

to generate, compile, and report data on the occurrence and fate of the 129 priority pollutants in 

50 POTWs. The report presents all of the data collected, the results of preliminary evaluations of 

these data, and the results of calculations to determine the following: 

� The quantity of priority pollutants in the influent to POTWs; 

� The quantity of priority pollutants discharged from the POTWs; 

� The quantity of priority pollutants in the effluent from intermediate 

process streams; and 

3-50

3.0 - Data Collection Activities 

� The quantity of priority pollutants in the POTW sludge streams. 

EPA used the data from this study to assess removal by POTWs of pollutants of concern (see 

Section 7). To provide consistency for data analysis and establishment of removal efficiencies, 

EPA reviewed the 50-POTW Study and standardized the reported minimum levels of 

quantitation (MLs) for use in the MP&M final rule. EPA’s review of the 50-POTW Study is 

described in more detail in the development document for the MP&M proposed regulation 

located in Section 7.2 of the rulemaking record, DCN 16377, and in memoranda located in 

Section 6.4 of the rulemaking record. 

3.6.3	 National Risk Management Research Laboratory (NRMRL) Treatability 

Database 

EPA’s ORD developed the NRMRL (formerly RREL) treatability database to 

provide data on the removal and destruction of chemicals in various types of media, including 

water, soil, debris, sludge, and sediment. This database contains treatability data from POTWs as 

well as industrial facilities for various pollutants. The database includes physical and chemical 

data for each pollutant, the types of treatment used for specific pollutants, the types of wastewater 

treated, the size of the POTW or industrial plant, and the treatment concentrations achieved. 

EPA used the NRMRL database to estimate pollutant reductions achieved by POTWs for MP&M 

pollutants of concern that were not found in the 50-POTW database. The Agency used these 

percent removal estimates in calculating the pollutant loads removed by indirect discharging 

facilities performing proposed MP&M operations. Because the 50-POTW database contained 

sufficient data, EPA did not use these percent removal estimates in the pass-through analysis. 

EPA used only treatment technologies representative of typical POTW secondary treatment 

operations (i.e., activated sludge, activated sludge with filtration, aerated lagoons). The Agency 

further edited these files to include information pertaining only to domestic or industrial 

wastewater. EPA used pilot-scale and full-scale data, and eliminated bench-scale data and data 

from less reliable references. 

3.6.4 The Domestic Sewage Study 

In February 1986, EPA issued the Report to Congress on the Discharge of 

Hazardous Wastes to Publicly Owned Treatment Works (8), referred to as the Domestic Sewage 

Study (DSS). This report, which was based in part on the 50-POTW Study, revealed a 

significant number of sites discharging pollutants to POTWs. These pollutants are a threat to the 

treatment capability of the POTW. These pollutants were not regulated by national effluent 

regulations. Some of the major sites identified were in the metals industries, particularly one 

called equipment manufacturing and assembly. This industry included sites that manufacture 

such products as office machines, household appliances, scientific equipment, and industrial 

machine tools and equipment. The DSS estimated that this category discharges 7,715 metric tons 

per year of priority hazardous organic pollutants, which are presently unregulated. Data on 

priority hazardous metals discharges were unavailable for this category. Further review of the 

DSS revealed miscellaneous categories that were related to metals industries, namely the motor 

3-51

3.0 - Data Collection Activities 

vehicle category, which includes servicing of new and used cars and engine and parts rebuilding, 

and the transportation services category, which includes railroad operations, truck service and 

repair, and aircraft servicing and repair. EPA used the information in the DSS in developing the 

1989 Preliminary Data Summary (PDS) for the MP&M rulemaking. 

3.6.5 Toxics Release Inventory (TRI) Database 

The TRI database contains specific toxic chemical release and transfer 

information from manufacturing facilities throughout the United States. This database was 

established under the Emergency Planning and Community Right-to-Know Act of 1986 

(EPCRA), which Congress passed to promote planning for chemical emergencies and to provide 

information to the public about the presence and release of toxic and hazardous chemicals. Each 

year, manufacturing facilities meeting certain activity thresholds must report the estimated 

releases and transfers of listed toxic chemicals to EPA and to the state or tribal entity in whose 

jurisdiction the facility is located. The TRI list includes more than 600 chemicals and 30 

chemical categories. 

EPA considered using the TRI database in developing the MP&M effluent 

guidelines. However, EPA did not use TRI data on wastewater discharges from facilities 

performing proposed MP&M operations because sufficient data were not available for effluent 

guidelines development. Also, many of the reported discharges are estimates, not based on 

measurement. For example, in developing the MP&M effluent guidelines, EPA uses wastewater 

influent concentrations to characterize a facility’s wastewater and to calculate treatment 

efficiency (i.e., percent removal across the treatment system). The TRI database does not provide 

concentrations for the influent to a facility’s treatment system. EPA also did not use the data on 

wastewater discharge because many facilities performing proposed MP&M operations do not 

meet the reporting thresholds for the TRI database. 

3.6.6 Discharge Monitoring Reports from EPA’s Permit Compliance System 

The PCS provides information on companies which have been issued permits to 

discharge wastewater into surface water. Users can review information on when a permit was 

issued and expires, how much the company is permitted to discharge, and the actual monitoring 

data showing what the company has discharged. Respondents to MP&M surveys and 

commentors on the May 1995 proposal, January 2001 proposal, and June 2002 NODA supplied 

facility specific DMR data. In addition, EPA retrieved facility limits and process wastewater 

monitoring data from facilities performing proposed MP&M operations for selected pollutant 

parameters (e.g., metals, oil and grease). EPA used DMR data to estimate industry baseline 

pollutant loadings. Section 12.3 discusses the estimation of baseline pollutant loadings using 

PCS data. 

3-52

3.0 - Data Collection Activities 

3.7 References 

1. U.S. Environmental Protection Agency. Sampling and Analysis Procedures for 

Screening of Industrial Effluents for Priority Pollutants, April 1977. 

2.	 U.S. Environmental Protection Agency. Method 1620 Draft - Metals by 

Inductively Coupled Plasma Atomic Emission Spectroscopy and Atomic 

Absorption Spectroscopy, September 1989. 

3.	 U.S. Environmental Protection Agency. Method 1624 Revision C - Volatile 

Organic Compounds by Isotope Dilution GCMS, June 1989. 

4.	 U.S. Environmental Protection Agency. Method 1625 Revision C - Semivolatile 

Organic Compounds by Isotope Dilution GCMS, June 1989. 

5.	 U.S. Environmental Protection Agency. Methods for Chemical Analysis of Water 

and Wastes. EPA-600/4-79-020, Washington, DC, March 1979. 

6.	 U.S. Environmental Protection Agency. Metal Finishing F006 Benchmark Study. 

Washington, DC, September 1998. 

7.	 U.S. Environmental Protection Agency. Fate of Priority Pollutants in Publicly 

Owned Treatment Works. EPA 440/1-82/303, Washington, DC, September 1982. 

8.	 U.S. Environmental Protection Agency. Report to Congress on the Discharge of 

Hazardous Wastes to Publicly Owned Treatment Works. EPA 530-SW-86-004, 

Washington, DC, February 1986. 

9.	 U.S. Environmental Protection Agency. Development Document for Final 

Effluent Limitations Guidelines and Standards for the Iron and Steel 

Manufacturing Point Source Category (EPA-821-R-02-004). 

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4.0 - Industry Description 

4.0 INDUSTRY DESCRIPTION 

As discussed in Section 1.0, EPA has promulgated effluent limitations for the 

MP&M Point Source Category that regulate directly discharged process wastewaters from oily 

operations at facilities engaged in manufacturing, rebuilding, or maintenance of metal parts, 

products, or machines for use in one or more of the following 16 industrial sectors: 

� Aerospace;


� Aircraft;


� Bus and Truck; 


� Electronic Equipment;


� Hardware;


� Household Equipment;


� Instruments;


� Mobile Industrial Equipment;


� Motor Vehicle;


� Office Machine;


� Ordnance; 


� Precious Metals and Jewelry;


� Railroad;


� Ships and Boats;


� Stationary Industrial Equipment; and


� Miscellaneous Metal Products.


This section describes these facilities. For the final rule, EPA evaluated facilities 

in the 16 MP&M industrial sectors above and Job Shop, Printed Wiring Board, and Steel 

Forming and Finishing industrial sectors (i.e., Iron & Steel Wire Drawers and Steel 

Electroplaters). For the purposes of this section, EPA is identifying all facilities evaluated for the 

final rule as “MP&M facilities.” Section 4.1 presents an overview of MP&M facilities; Section 

4.2 provides a general discussion of unit operations performed, types of metal processed, and 

volumes of wastewater discharged at MP&M facilities; Section 4.3 discusses trends at MP&M 

facilities; and Section 4.4 lists the references used in this section. 

4.1 Overview of MP&M facilities 

This subsection discusses the number and size of MP&M facilities evaluated for 

regulation, the geographic distribution of these facilities, the number of wastewater-discharging 

MP&M facilities, and the number of MP&M facilities that do not discharge wastewater. 

4-1

4.0 - Industry Description 

4.1.1 Number and Size of MP&M Facilities 

Based on information in the MP&M survey database, there are an estimated 

57,000 MP&M facilities in the United States.1 Results of the detailed surveys indicate there are 

an estimated 44,000 MP&M facilities that discharge process wastewater (i.e., wastewaterdischarging MP&M facilities). The remaining 13,000 facilities fall into one of three categories: 

zero dischargers, non-water-users, or contract haulers. A zero discharger is a facility that does 

not discharge process wastewater to a treatment system, a non-water-user is a facility that does 

not use process water in their unit operations, and a contract hauler is a facility that has all of 

their process wastewater contract hauled. For the purposes of the evaluating options for the final 

rule, EPA considers MP&M facilities that discharge wastewater exclusively to privately owned 

treatment works to be zero dischargers that contract haul their wastewater to centralized 

wastewater treatment facilities. 

Wastewater-discharging MP&M facilities range in size from facilities with less 

than 10 employees to facilities with thousands of employees. As shown in Figure 4-1, 91 percent 

of the wastewater-discharging MP&M facilities have 500 or fewer employees. These facilities 

discharge 55 percent (i.e., 43 billion gallons per year) of the total annual wastewater discharge 

for the MP&M industry. The 9 percent of the wastewater-discharging MP&M facilities that have 

more than 500 employees discharge 35 billion gallons of wastewater annually, or 45 percent of 

the total annual wastewater discharge for the MP&M category. 

1

More information on how the MP&M survey database was used to generate national estimates is in the MP&M 

rulemaking record (see Section 10.0, DCN 16118 and Section 19.5, DCNs 36086 and 36087). 

4-2 
4.0 - Industry Description 

60 

47% 

1% 

17% 

7% 9% 8% 

18% 

39% 

8% 9% 

2% 

22% 

<1% 

13% 

<1% 1% 

Percentage of MP&M Wastewater-Discharging Sites 

Percentage of Total Annual MP&M Discharge Flow 

50 

40 

Percentage 30 

20 

10 

0 

<=10 11-50 51-100 101-500 501-1,000 1,001-5,000 5,001-10,000 >10,000 

Number of Employees 

Source: MP&M Survey Database. 

Note: There are 44,000 wastewater-discharging MP&M facilities. Total MP&M wastewater 

flow is 78.2 billion gallons per year. 

Figure 4-1. Percentage of Wastewater-Discharging MP&M facilities and 

Percentage of Annual Wastewater Discharge by Number of Employees 

4.1.2 Geographic Distribution 

Wastewater-discharging MP&M facilities are located throughout the United 

States. They are mostly concentrated in industrialized areas, with the highest concentration of 

facilities in California, Pennsylvania, and Illinois. The following map shows the estimated 

number of wastewater-discharging MP&M facilities located in each EPA region. 

4-3

4.0 - Industry Description

4-4

Figure 4-2. ated Number of Wastewater-Discharging MP&M facilities by EPA

Region

4.1.3 Wastewater-Discharging Facilities

EPA evaluated MP&M facilities in 20 industrial sectors for the final rule. Table 4-

1 summarizes the number of wastewater-discharging MP&M facilities by industrial sector. 

Because some MP&M facilities perform operations or make products used in more than one

sector, the sum of wastewater-discharging MP&M facilities by sector exceeds the total number of

wastewater-discharging MP&M facilities identified in the surveys. As shown in Table 4-1, the

ordnance sector has the smallest number of wastewater-discharging facilities (405) and the job

shop sector has the largest number of wastewater-discharging facilities (14,589).

Estim
4.0 - Industry Description 

Table 4-1


Wastewater-Discharging MP&M facilities by Sector


Sector 

Estimated Number of MP&M Facilities That 

Discharge Process Wastewatera 

Aerospace 712 

Aircraft 1,598 

Bus and Truck 3,522 

Electronic Equipment 2,644 

Hardware 6,223 

Household Equipment 3,137 

Instruments 3,902 

Iron and Steel Wire Drawersb , c 153 

Job Shop c 14,589 

Miscellaneous Metal Products 5,316 

Mobile Industrial Equipment 1,079 

Motor Vehicle 13,070 

Office Machine 1,092 

Ordnance 405 

Precious Metals and Jewelry 1,860 

Printed Circuit Boards c 1,456 

Railroad 5,181 

Ships and Boats 1,367 

Stationary Industrial Equipment 1,724 

Steel Electroplatersb , c 28 

Source: MP&M Survey Database.
 a Because some facilities perform unit operations in more than one sector, the sum of facilities by sector exceeds the


total number of facilities that discharge wastewater (44,000). 
 b

 Technical surveys for these facilities did not include sector information; therefore, they were listed separately for


this table.
 c

 These industrial sectors are not included in the final rule.


4-5

4.0 - Industry Description 

In addition to description by industrial sector, MP&M operations2 that were 

proposed for regulation can be described by two types of activities: manufacturing and 

rebuilding/maintenance. 

� Manufacturing is the series of unit operations necessary to produce metal 

products, and is generally performed in a production environment. 

� Rebuilding/maintenance is the series of unit operations necessary to 

disassemble used metal products into components, replace the components 

or subassemblies or restore them to original function, and reassemble the 

metal products. These operations are intended to keep metal products in 

operating condition and can be performed in either a production or a 

nonproduction environment. 

Figure 4-3 presents the percentage of wastewater-discharging MP&M facilities 

and percentage of the total annual wastewater discharge by activity. Eighty-two percent of the 

annual wastewater discharge is discharged by facilities with only manufacturing operations. 

These facilities represent 35 percent of the total wastewater-discharging MP&M facilities. The 

highest percentage of the MP&M facilities (i.e., 50 percent) have only rebuilding and 

maintenance operations. 

2

EPA evaluated a number of unit operations for the May 1995 proposal, January 2001 proposal, and June 2002 

Notice of Data Availability (NODA) (see Tables 4-3 and 4-4). However, EPA selected a subset of these unit 

operations for regulation in the final rule (see section 1.0). For this section, the term “proposed MP&M operations” 

means those operations evaluated for the two proposals, NODA, and final rule. The term “Final MP&M operations” 

means those operations defined as “oily operations” (see Section 1.0, 40 CFR 438.2(f), and Appendix B to Part 438) 

and regulated by the final rule. 

4-6 
4.0 - Industry Description 

80 

70 

60 

50 

15% 

12% 

35% 

82% 

50% 

6% 

Percentage of MP&M WastewaterDischarging Sites 

Percentage of Total Anuual MP&M 

Discharge Flow 

Percentage 40 

30 

20 

10 

0 

Manufacturing and Manufacturing Only Rebuilding/Maintenance Only 

Rebuilding/Maintenance 

Activity 

Source: MP&M Survey Database. 

Note: There are 44,000 wastewater-discharging MP&M facilities. Total MP&M wastewater 

flow is 78.2 billion gallons per year. 

Figure 4-3. Percentage of Wastewater-Discharging MP&M facilities and 

Percentage of Total Annual Discharge by Activity 

Wastewater-discharging MP&M facilities include direct dischargers, indirect 

dischargers, and those that are both direct and indirect dischargers. A direct discharger is a 

facility that discharges wastewater to a surface water (e.g., river, lake, ocean). An indirect 

discharger is a facility that discharges wastewater to a publicly owned treatment works (POTW). 

Figure 4-4 presents the percentage of wastewater-discharging MP&M facilities and the 

percentage of the total annual wastewater discharge by discharge status. This figure shows that 

the highest percentage of wastewater-discharging MP&M facilities are indirect dischargers, and 

those facilities account for 85 percent of the total annual discharge from all MP&M facilities. 

4-7

4.0 - Industry Description 

100 

90 

80 

70 

60 

Percentage 50 

40 

30 

20 

10 

0 

Direct and Indirect Direct Indirect 

<1% <1% 6% 

15% 

94% 

85% 

Percentage of MP&M Wastewater-Discharging Sites 

Percentage of Total Annual MP&M Discharge Flow 

Discharge Destination 

Source: MP&M Survey Database. 

Note: There are 44,000 wastewater-discharging MP&M facilities. Total MP&M wastewater 

flow is 78.2 billion gallons per year. 

Figure 4-4. Percentage of Wastewater-Discharging MP&M facilities and 

Percentage of Total Annual Discharge by Discharge Status 

Wastewater discharge flow rates for MP&M facilities range from less than 100 

gallons per year to greater than 100 million gallons per year. Figure 4-5 presents the percentage 

of wastewater-discharging MP&M facilities and the percentage of the annual MP&M wastewater 

discharge by range of wastewater flow rates. As this figure shows, MP&M facilities discharging 

more than one million gallons per year (approximately 12 percent of the total facilities) account 

for approximately 95 percent of the total annual wastewater discharge for all MP&M facilities. 

In contrast, facilities discharging less than 100,000 gallons per year (approximately 62 percent of 

the total facilities) account for less than one percent of the total annual wastewater discharge for 

all MP&M facilities. 

4-8

4.0 - Industry Description 

50 

45 

40 

35 

30 

5% 

<1% 

30% 

<1% 

10% 

<1% 

17% 

<1% 

25% 

5% 

9% 

18% 

3% 

47% 

<1% 

30% 

Percentage of MP&M Wastewater-Discharging Sites 

Percentage of Total Annual MP&M Discharge Flow 

Percentage 25 

20 

15 

10 

5 

0 

0-100 101-1,000 1,001-10,000	 10,001- 100,001- 1,000,001- 10,000,001- >100,000,000 

100,000 1,000,000 10,000,000 100,000,000 

Discharge Flow Range (GPY) 

Source: MP&M Survey Database. 

Note: There are 44,000 wastewater-discharging MP&M facilities. Total MP&M wastewater 

flow is 78.2 billion gallons per year. 

Figure 4-5. Percentage of Wastewater-Discharging MP&M facilities and 

Percentage of Total Annual MP&M Discharge by Flow Rate Range 

4.1.4 Non-Wastewater-Discharging Facilities 

Based on the results of the detailed MP&M surveys, an estimated 13,000 MP&M 

facilities either generate process water and do not discharge wastewater (i.e., zero discharge or 

contract haulers) or do not use process water (dry facilities). Information from the MP&M 

detailed surveys, site visits, and technical literature indicates these facilities achieve zero 

discharge of process wastewater in one of the following ways: 

� Contract haul all process wastewater generated on site; 

� Discharge process wastewater to either on-site septic systems or deep-well 

injection systems; 

4-9

4.0 - Industry Description 

� Perform end-of-pipe treatment and reuse all process wastewater generated 

on site; 

� Perform either in-process or end-of-pipe evaporation to eliminate 

wastewater discharges; or 

� Perform in-process recirculation and recycling to eliminate wastewater 

discharges. 

As discussed in Section 3.0, EPA mailed the 1989 detailed survey to a probability 

sample of 50 screener respondents that reported using but not discharging process water. Based 

on the survey responses, 5 of these facilities contract hauled all wastewater generated on site, 8 

actually discharged process wastewater, 18 had no process wastewater discharges, and 19 were 

not engaged in proposed MP&M operations. The Agency also mailed the 1989 detailed survey 

to an additional 24 screener respondents that reported using but not discharging process water. 

As discussed in Section 3.0, EPA selected these facilities because they performed unit operations 

that were not expected to be characterized sufficiently by detailed surveys mailed to other 

facilities. Of the additional 24, 14 actually discharged process wastewater, 2 had no process 

wastewater discharges, and 8 were not engaged in proposed MP&M operations. Of the 74 

screener respondents that received the 1989 detailed survey, only 20 reported no discharge of 

process water. 

In addition to the 20 facilities discussed above that do not discharge process 

wastewater, 205 of the 1996 screener survey respondents reported eliminating wastewater 

discharges by in-process or end-of-pipe evaporation, end-of-pipe treatment and reuse, in-process 

recirculation and recycling, or other unspecified means. Figure 4-6 shows the percentage of the 

facilities using each type of zero discharge method. Note that Figure 4-6 provides the percentage 

of survey respondents, not industry percentages, because this information was available for only 

a subset of the industry. The methods used by the 225 survey facilities to eliminate wastewater 

discharges are discussed below. 

In-Process or End-Of-Pipe Evaporation. Forty-one percent of the screener 

survey respondents (i.e., 92 respondents) reported discharging wastewater to either evaporators, 

on-site ponds, or lagoons to evaporate process wastewater. None of these facilities reported 

recovering the process wastewater. Facilities reported contracting for off-site disposal of sludge 

from the evaporation units. 

End-Of-Pipe Treatment and Reuse. Eight percent of the screener survey 

respondents (i.e., 18 respondents) reported eliminating wastewater discharges through end-ofpipe treatment and reuse of all wastewater generated on site. 

4-10

4.0 - Industry Description 

U nkn ow n M etho d s 

-O fO t h er I n -P ro ce s s o r E n d 

I n -P ro ce s s 

12 % 

P ip e E v ap o rat io n 

1 6 % 4 1 % 

End-O f-P ip e R ecircu lat io n an d T re at m en t an d R eu s e 

R ecy c lin g 8% 

2 3 % 

Note: There are 225 survey facilities that have eliminated wastewater discharge. 

Figure 4-6. Percentage of Screener Survey Respondents 

Using Each Zero Discharge Method 

In-Process Recirculation and Recycling. Twenty-three percent of the screener 

survey respondents (i.e., 52 respondents) reported eliminating wastewater discharges through inprocess recirculation and recycling. Several facilities used a stagnant bath in their heat treating 

operations. Some facilities used stagnant baths in their surface finishing operations (e.g., alkaline 

cleaning and chemical conversion coating). Make-up water is added to the stagnant baths to 

account for losses of bath water through evaporation. 

Other. Sixteen percent of the screener survey respondents (i.e., 36 respondents) 

reported eliminating wastewater discharge through a variety of other methods including land 

application and septic tank systems or contract hauling through a centralized waste treater (CWT) 

or privately owned treatment works (PrOTW). 

4.2 Proposed MP&M Operations 

This subsection discusses the proposed MP&M operations and presents a brief 

description of each unit operation. It also discusses the metals processed in proposed MP&M 

operations, and presents an estimate of the annual wastewater discharge for each proposed 

MP&M operations. 

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4.2.1 Types of Unit Operations 

MP&M facilities perform several different types of unit operations and associated 

rinses on metal parts, products, and machines. Section 4.2.2 describes these unit operations. 

The types of proposed MP&M operations include:


� Metal shaping;


� Surface preparation;


� Metal deposition;


� Organic material deposition;


� Surface finishing;


� Assembly;


� Dry dock; and 


� Specialized printed wiring board operations.


Metal shaping is a mechanical operation that alters the form of raw materials into 

intermediate and final products. Surface preparation includes chemical and mechanical 

operations that remove unwanted materials from or alter the chemical or physical properties of 

the part surface prior to subsequent proposed MP&M operations. Metal deposition applies a 

metal coating to the part surface by chemical or physical means. Organic material deposition 

applies an organic material to the part by chemical or physical means. Facilities may perform 

metal and organic material deposition to protect the surface from wear or corrosion, modify the 

electrical properties of the surface, or alter the appearance of the surface. Surface finishing 

protects and seals the surface of the treated part from wear or corrosion by chemical means. 

Facilities also may use surface finishing to alter the appearance of the part surface. Assembly is 

performed throughout the manufacturing, rebuilding, or maintenance process. Dry dock 

operations are proposed MP&M operations performed at ship and boat facilities within dry docks 

or similar structures and incorporate many types of proposed MP&M operations. Printed wiring 

board unit operations are those specific to the manufacture or rebuilding/maintenance of wiring 

boards (e.g., carbon black deposition, solder flux cleaning, and photo image developing). 

Specialized printed wiring board operations do not include those performed at assembly-only 

facilities. Table 4-2 lists examples of the different types of proposed MP&M operations. 

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Table 4-2


Types of Proposed MP&M operations 


Type of Unit Operations Example 

Metal Shaping Machining, Grinding, Deformation 

Surface Preparation Alkaline Cleaning, Acid Treatment 

Metal Deposition Electroplating, Vapor Deposition 

Organic Material Deposition Painting 

Surface Finishing Chemical Conversion Coating 

Assembly Testing (e.g., leak testing), Assembly 

Dry Dock Welding 

Specialized Printed Wiring Board Solder Leveling, Photoresist Applications 

At a given MP&M facility, the specific unit operations and the sequence of 

operations depend on many factors, including the activity at the facility (i.e., manufacturing, 

rebuilding/maintenance), industrial sector, and type of product processed. As a result, MP&M 

facilities perform many different combinations and sequences of unit operations. For example, 

MP&M facilities that repair, rebuild or maintain products often conduct preliminary operations 

that may not be performed at manufacturing facilities (e.g., disassembly, cleaning, or degreasing 

to remove dirt and oil accumulated during use of the product). In general, however, MP&M 

products are processed in the following order: 

� The raw material (e.g., bar stock, wire, rod, sheet stock, plates) undergoes 

some type of metal-shaping process, such as impact or pressure 

deformation, machining, or grinding. In these operations, the raw material 

is shaped into intermediate forms for further processing or into final forms 

for assembly and shipment to the customer. Facilities typically clean and 

degrease the parts between some of the shaping operations to remove 

lubricants, coolants, and metal fines. Facilities also may heat a part 

between shaping operations to alter its physical characteristics. 

� After shaping, the part typically undergoes some type of surface 

preparation, such as alkaline cleaning, acid treatment (pickling), or barrel 

finishing. The specific operation depends on the subsequent unit 

operations and the final use of the products. For example, prior to 

electroplating, parts typically go through acid pickling (i.e., acid cleaning) 

to prepare the part surface for electroplating. Before assembly, parts 

typically go through alkaline cleaning or barrel finishing. Parts go through 

surface preparation at various stages of the production process. Additional 

cleaning and degreasing steps precede metal deposition, organic material 

deposition, surface finishing, and assembly. 

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� Metal and organic material deposition typically follow shaping and surface 

preparation, and precede surface finishing and final assembly. For 

example, electroplating usually follows alkaline and acid treatment, while 

painting usually follows phosphate conversion coating and alkaline 

treatment. 

� Surface finishing operations typically are performed after shaping and 

surface preparation. Some surface finishing is performed after metal 

deposition. For example, chromate conversion coating typically follows 

acid cleaning, although this operation is sometimes performed as a sealant 

operation after electroplating (e.g., chemical conversion coating of 

cadmium plated parts). Surface finishing also is done prior to applying 

organic coatings. For example, phosphate conversion coating frequently 

precedes painting to enhance the paint adhesion. 

� Disassembly may be the first step in the rebuilding process. Assembly, on 

the other hand, is done during many steps of the manufacturing and 

rebuilding process to prepare the final product. Assembly also may 

involve some final shaping (e.g., drilling and grinding) and surface 

preparation (e.g., alkaline cleaning). Final assembly usually is the last 

operation prior to shipment to the customer. 

Some MP&M facilities conduct all of these types of unit operations in 

manufacturing or rebuilding products, while others may perform only some types. For example, 

a facility that manufactures products used in the hardware sector may start with bar stock and 

manufacture a final hardware product, performing machining, cleaning, electroplating, 

conversion coating, painting, degreasing, and assembly. Another hardware product 

manufacturing facility may only clean and paint the parts. A third hardware product 

manufacturing facility may only shape the parts, and perform only machining, cleaning, and 

degreasing operations. 

4.2.2 Description of Proposed MP&M Operations 

EPA described the operations above as either metal-bearing operations or oily 

operations. This section describes each of the MP&M operations for which EPA considered new 

regulations. Oily operations (as defined in 40 CFR 438.2(f)) are listed in Table 4-3. Metalbearing operations (as defined in 40 CFR 438.2(d)) are listed in Table 4-4. 

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Table 4-3


List of MP&M Oily Operations


� Abrasive Blasting � Iron Phosphate Conversion Coating


� Adhesive Bonding � Machining


� Alkaline Cleaning for Oil Removal � Painting-spray or Brush (Including Water Curtains)


� Alkaline Treatment Without Cyanide � Polishing


� Aqueous Degreasing � Pressure Deformation 


� Assembly/Disassembly � Solvent Degreasing


� Burnishing � Steam Cleaning


� Calibration � Testing (e.g., Hydrostatic, Dye Penetrant, Ultrasonic, Magnetic


� Corrosion Preventive Coating 

Flux)


� Electrical Discharge Machining � Thermal Cutting


� Floor Cleaning (In Process Area) � Tumbling/Barrel Finishing/Mass Finishing/Vibratory Finishing 


� Grinding � Washing (Finished Products)


� Heat Treating � Welding


� Impact Deformation � Wet Air Pollution Control for Organic Constituents


Note: This list is replicated at 40 CFR 438.2(f) with definitions at Appendix B to Part 438. 

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Table 4-4


List of MP&M Metal-Bearing Operations


� Abrasive Jet Machining � Mechanical and Vapor Plating 

� Acid Pickling Neutralization � Metallic Fiber Cloth Manufacturing 

� Acid Treatment With Chromium � Metal Spraying (including Water Curtain) 

� Acid Treatment Without Chromium � Painting-immersion (including Electrophoretic, 

"E-coat") 

� Alcohol Cleaning � Photo Imaging 

� Alkaline Cleaning Neutralization � Photo Image Developing 

� Alkaline Treatment With Cyanide � Photoresist Application 

� Anodizing With Chromium � Photoresist Strip 

� Anodizing Without Chromium � Phosphor Deposition 

� Carbon Black Deposition � Physical Vapor Deposition 

� Catalyst Acid Pre-dip � Plasma Arc Machining 

� Chemical Conversion Coating Without Chromium � Plastic Wire Extrusion 

� Chemical Milling (or Chemical Machining) � Salt Bath Descaling 

� Chromate Conversion Coating (or Chromating) � Shot Tower - Lead Shot Manufacturing 

� Chromium Drag-out Destruction � Soldering 

� Cyanide Drag-out Destruction � Solder Flux Cleaning 

� Cyaniding Rinse � Solder Fusing 

� Electrochemical Machining � Solder Masking 

� Electroless Catalyst Solution � Sputtering 

� Electroless Plating � Stripping (paint) 

� Electrolytic Cleaning � Stripping (metallic coating) 

� Electroplating With Chromium � Thermal Infusion 

� Electroplating With Cyanide � Ultrasonic Machining 

� Electroplating Without Chromium or Cyanide � Vacuum Impregnation 

� Electropolishing � Vacuum Plating 

� Galvanizing/Hot Dip Coating � Water Shedder 

� Hot Dip Coating � Wet Air Pollution Control 

� Kerfing � Wire Galvanizing Flux 

� Laminating 

Note: This list is replicated at 40 CFR 438.2(d) with definitions at Appendix C to Part 438. 

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EPA also evaluated process wastewater from “Bilge Water” and “Dry 

Dock/Stormwater” for the final rule. These two processes generate mainly oily or organic 

wastewater but are not included in the final definition of “oily operations” (as defined in 40 CFR 

438.2(f)) as these unit operations only occur at facilities EPA decided should not be subject to the 

final rule (see 40 CFR 438.1(e)(5)). EPA used the following definitions for “Bilge Water” and 

“Dry Dock/Stormwater” for the final rule: 

� Bilge Water is water that collects in the inner hull of a ship. When a ship 

is in a dry dock or similar structure, the bilge water is collected and then 

treated and disposed of. 

� Dry Dock/Stormwater. Maintenance operations performed on a 

ship/boat in a dry dock that either use process water or are exposed to 

stormwater. 

The following descriptions are provided to aid the reader in understanding the 

described processes and do not supersede regulatory definitions of unit operations in the final 

MP&M rule. Moreover, the definitions in this section should not be used to differentiate 

between the six “core” metal finishing operations (i.e., Electroplating, Electroless Plating, 

Anodizing, Coating (chromating, phosphating, and coloring), Chemical Etching and Milling, and 

Printed Circuit Board Manufacture) and 40 “ancillary” process operations listed at 40 CFR 

433.10(a). 

4.2.2.1 Description of MP&M Oily Operations 

Abrasive Blasting involves removing surface film from a part by using abrasive directed at high 

velocity against the part. Abrasive blasting includes bead, grit, shot, and sand blasting, and may 

be performed either dry or with water. The primary applications of wet abrasive blasting include: 

removing burrs on precision parts; producing satin or matte finishes; removing fine tool marks; 

and removing light mill scale, surface oxide, or welding scale. Wet blasting can be used to finish 

fragile items such as electronic components. Also, some aluminum parts are wet blasted to 

achieve a fine-grained matte finish for decorative purposes. In abrasive blasting, the water and 

abrasive typically are reused until the particle size diminishes due to impacting and fracture. 

Adhesive Bonding involves joining parts using an adhesive material. Typically, an organic 

bonding compound is used as the adhesive. This operation usually is dry; however, aqueous 

solutions may be used as bonding agents or to contain residual organic bonding materials. 

Alkaline Cleaning for Oil Removal is a general term for the application of an alkaline cleaning 

agent to a metal part to remove oil and grease during the manufacture, maintenance, or rebuilding 

of a metal product. 

This unit operation does not include washing of the finished products after routine use (as 

defined in “Washing (Finished Products)” in this subsection), or applying an alkaline cleaning 

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agent to remove nonoily contaminants such as dirt and scale (as defined in “Alkaline Treatment 

Without Cyanide” in this subsection and “Alkaline Treatment With Cyanide” in Section 4.2.2.2). 

Wastewater generated includes spent cleaning solutions and rinse waters. 

� Alkaline cleaning is performed to remove foreign contaminants from 

parts. This operation usually is done prior to finishing (e.g., 

electroplating). 

� Emulsion cleaning is an alkaline cleaning operation that uses either 

complex chemical enzymes or common organic solvents (e.g., kerosene, 

mineral oil, glycols, and benzene) dispersed in water with the aid of an 

emulsifying agent. The pH of the solvent usually is between 7 and 9, and, 

depending on the solvent used, cleaning is performed at temperatures from 

room temperature to 82°C (180°F). This operation often is used as a 

replacement for vapor degreasing. 

Alkaline Treatment Without Cyanide is a general term used to describe the application of an 

alkaline solution not containing cyanide to a metal surface to clean the metal surface or prepare 

the metal surface for further surface finishing. 

Aqueous Degreasing involves cleaning metal parts using aqueous-based cleaning chemicals 

primarily to remove residual oils and greases from the part. Residual oils can be from previous 

operations (e.g., machine coolants), oil from product use in a dirty environment, or oil coatings 

used to inhibit corrosion. Wastewater generated by this operation includes spent cleaning 

solutions and rinse waters. 

Assembly/Disassembly involves fitting together previously manufactured or rebuilt parts or 

components into a complete metal product or machine or taking a complete metal product or 

machine apart. Assembly/disassembly operations are typically dry; however, special 

circumstances can require water for cooling or buoyancy. Also, rinsing may be necessary under 

some conditions. 

Burnishing involves finish sizing or smooth finishing a part (previously machined or ground) by 

displacing, rather than removing, minute surface irregularities with smooth point or line-contact, 

fixed or rotating tools. Lubricants or soap solutions can be used to cool the tools used in 

burnishing operations. Wastewater generated during burnishing include process solutions and 

rinse water. 

Calibration is performed to provide reference points for the use of a product. This unit operation 

typically is dry, although water may be used in some cases (e.g., pumping water for calibration of 

a pump). Water used in this unit operation usually does not contain additives. 

Corrosion Preventive Coating involves applying removable oily or organic solutions to protect 

metal surfaces against corrosive environments. Corrosion preventive coatings include, but are not 

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limited to: petrolatum compounds, oils, hard dry-film compounds, solvent-cutback petroleumbased compounds, emulsions, water-displacing polar compounds, and fingerprint removers and 

neutralizers. Corrosion preventive coating does not include electroplating or chemical conversion 

coating operations. 

Many corrosion preventive materials also are formulated to function as lubricants or as a base for 

paint. Typical applications include: assembled machinery or equipment in standby storage; 

finished parts in stock or spare parts for replacement; tools such as drills, taps, dies, and gauges; 

and mill products such as sheet, strip, rod and bar. 

Wastewater generated during corrosion preventive coating includes spent process solutions and 

rinses. Process solutions are discharged when they become contaminated with impurities or are 

depleted of constituents. Corrosion preventive coatings typically do not require an associated 

rinse, but parts are sometimes rinsed to remove the coating before further processing. 

Electrical Discharge Machining involves removing metals by a rapid spark discharge between 

different polarity electrodes, one the part and the other the tool, separated by a small gap. The gap 

may be filled with air or a dielectric fluid. This operation is used primarily to cut tool alloys, hard 

nonferrous alloys, and other hard-to-machine materials. Most electrical discharge machining 

processes are operated dry; however, in some cases, the process uses water and generates 

wastewater containing dielectric fluid. 

Floor Cleaning (in Process Area) removes dirt, debris, and process solution spills from process 

area floors. Floors can be cleaned using wet or dry methods, such as vacuuming, mopping, dry 

sweeping, and hose rinsing. Nonprocess area floor cleaning in offices and other similar 

nonprocess areas is not included in this unit operation. 

Grinding involves removing stock from a part by using abrasive grains held by a rigid or 

semirigid binder. Grinding shapes or deburrs the part. The grinding tool usually is a disk (the 

basic shape of grinding wheels), but can also be a cylinder, ring, cup, stick, strip, or belt. The 

most commonly used abrasives are aluminum oxide, silicon carbide, and diamond. The process 

may use a grinding fluid to cool the part and remove debris or metal fines. 

Wastewater generated during grinding includes spent coolants and rinses. Metal-working fluids 

become spent for a number of reasons, including increased biological activity (i.e., the fluids 

become rancid) or decomposition of the coolant additives. Rinse waters typically are assimilated 

into the working fluid or treated on site. 

Heat Treating involves modifying the physical properties of a part by applying controlled 

heating and cooling cycles. This operation includes tempering, carburizing, cyaniding, nitriding, 

annealing, aging, normalizing, austenitizing, austempering, siliconizing, martempering, and 

malleablizing. Parts are heated in furnaces or molten salt baths, and then may be cooled by 

quenching in aqueous solutions (e.g., brine solutions), neat oils (pure oils with little or no 

impurities), or oil/water emulsions. Heat treating typically is a dry operation, but is considered a 

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wet operation if aqueous quenching solutions are used. Wastewater includes spent quench water 

and rinse water. 

Impact Deformation involves applying impact force to a part to permanently deform or shape it. 

Impact deformation may include mechanical processes such as hammer forging, shot peening, 

peening, coining, high-energy-rate forming, heading, or stamping. 

Natural and synthetic oils, light greases, and pigmented lubricants are used in impact deformation 

operations. Pigmented lubricants include whiting, lithapone, mica, zinc oxide, molybdenum 

disulfide, bentonite, flour, graphite, white lead, and soap-like materials. 

These operations typically are dry, but wastewater can be generated from lubricant discharge and 

from rinsing operations associated with the operation. 

Iron Phosphate Conversion Coating is the process of applying a protective coating on the 

surface of a metal using a bath consisting of a phosphoric acid solution containing no metals 

(e.g., manganese, nickel, or zinc) or a phosphate salt solution (i.e., sodium or potassium salts of 

phosphoric acid solutions) containing no metals (e.g., manganese, nickel, or zinc) other than 

sodium or potassium. Any metal concentrations in the bath are from the substrate. 

Machining involves removing stock from a part (as chips) by forcing a cutting tool against the 

part. This includes machining processes such as turning, milling, drilling, boring, tapping, 

planing, broaching, sawing, shaving, shearing, threading, reaming, shaping, slotting, hobbing, 

and chamfering. Machining processes use various types of metal-working fluids, the choice of 

which depends on the type of machining being performed and the preference of the machine 

shop. The fluids can be categorized into four groups: straight oil (neat oils), synthetic, 

semisynthetic, and water-soluble oil. 

Machining operations generate wastewater from working fluid or rinse water discharge. Metalworking fluids periodically are discarded because of reduced performance or development of a 

rancid odor. After machining, parts are sometimes rinsed to remove coolant and metal chips. The 

coolant reservoir is sometimes rinsed, and the rinse water is added to the working fluid. 

Painting - Spray or Brush (Including Water Curtains) involves applying an organic coating 

to a part. Coatings such as paint, varnish, lacquer, shellac, and plastics are applied by spraying, 

brushing, roll coating, lithographing, powder coating, and wiping. 

Water is used in painting operations as a solvent (water-borne formulations) for rinsing, for 

cleanup, and for water-wash (or curtain) type spray booths. Paint spray booths typically use most 

of the water in this unit operation. Spray booths capture overspray (i.e., paint that misses the 

product during application), and control the introduction of pollutants into the workplace and 

environment. 

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Polishing involves removing stock from a part using loose or loosely held abrasive grains carried 

to the part by a flexible support. Usually, the objective is to achieve a desired surface finish or 

appearance rather than to remove a specified amount of stock. Buffing is included in this unit 

operation, and usually is performed using a revolving cloth or sisal buffing wheel, which is 

coated with a suitable compound. Liquid buffing compounds are used extensively for largevolume production on semiautomated or automated buffing equipment. Polishing operations 

typically are dry, although liquid compounds and associated rinses are used in some polishing 

processes. 

Pressure Deformation involves applying force (other than impact force) to permanently deform 

or shape a part. Pressure deformation may include rolling, drawing, bending, embossing, sizing, 

extruding, squeezing, spinning, necking, forming, crimping or flaring. 

These operations use natural and synthetic oils, light greases, and pigmented lubricants. 

Pigmented lubricants include whiting, lithapone, mica, zinc oxide, molybdenum disulfide, 

bentonite, flour, graphite, white lead, and soap-like materials. 

Pressure deformation typically is dry, but wastewater is sometimes generated from the discharge 

of lubricants or from rinsing associated with the process. 

Solvent Degreasing removes oils and grease from the surface of a part using organic solvents, 

including aliphatic petroleum (e.g., kerosene, naphtha), aromatics (e.g., benzene, toluene), 

oxygenated hydrocarbons (e.g., ketones, alcohol, ether), and halogenated hydrocarbons (e.g., 

1,1,1-trichloroethane, trichloroethylene, methylene chloride). 

Solvent cleaning takes place in either the liquid or vapor phase. Solvent vapor degreasing 

normally is quicker than solvent liquid degreasing. However, ultrasonic vibration is sometimes 

used with liquid solvents to decrease the required immersion time of complex shapes. Solvent 

cleaning often is used as a precleaning operation prior to alkaline cleaning, as a final cleaning of 

precision parts, or as surface preparation for some painting operations. Solvent degreasing 

operations typically are not followed by rinsing, although rinsing is performed in some cases. 

Steam Cleaning removes residual dirt, oil, and grease from parts after processing though other 

unit operations. Typically, additives are not used in this operation; the hot steam removes the 

pollutants. Wastewater is generated when the cleaned parts are rinsed. 

Testing (e.g., hydrostatic, dye penetrant, ultrasonic, magnetic flux) involves applying 

thermal, electrical, mechanical, hydraulic, or other energy to determine the suitability or 

functionality of a part, assembly, or complete unit. Testing also may include applying surface 

penetrant dyes to detect surface imperfections. Other examples of tests frequently performed 

include electrical testing, performance testing, and ultrasonic testing; these tests typically are dry 

but may generate wastewater under certain circumstances. Testing usually is performed to 

replicate some aspect of the working environment. Wastewater generated during testing includes 

spent process solutions and rinses. 

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Thermal Cutting involves cutting, slotting, or piercing a part using an oxy-acetylene oxygen 

lance, electric arc cutting tool, or laser. Thermal cutting typically is a dry process, except for the 

use of contact cooling waters and rinses. 

Tumbling/Barrel Finishing/Mass Finishing/Vibratory Finishing involves polishing or 

deburring a part using a rotating or vibrating container and abrasive media or other polishing 

materials to achieve a desired surface appearance. Parts to be finished are placed in a rotating 

barrel or vibrating unit with an abrasive media (e.g., ceramic chips, pebbles), water, and chemical 

additives (e.g., alkaline detergents). As the barrel rotates, the upper layer of the part slides toward 

the lower side of the barrel, causing the abrading or polishing. Similar results can be achieved in 

a vibrating unit, where the entire contents of the container are in constant motion, or in a 

centrifugal unit, which compacts the load of media and parts as the unit spins and generates up to 

50 times the force of gravity. Spindle finishing is a similar process, where parts to be finished are 

mounted on fixtures and exposed to a rapidly moving abrasive slurry. 

Wastewater generated during barrel finishing includes spent process solutions and rinses. 

Following the finishing process, the contents of the barrel are unloaded. Process wastewater is 

either discharged continuously during the process, discharged after finishing, or collected and 

reused. The parts are sometimes given a final rinse to remove particles of abrasive media. 

Washing (Finished Products) involves cleaning finished metal products after use or storage 

using fresh water or water containing a mild cleaning solution. This unit operation applies only to 

the finished products that do not require maintenance or rebuilding. 

Welding involves joining two or more pieces of material by applying heat, pressure, or both, 

with or without filler material, to produce a metallurgical bond through fusion or recrystallization 

across the interface. This includes gas welding, resistance welding, arc welding, cold welding, 

electron beam welding, and laser beam welding. Welding typically is a dry process, except for 

the occasional use of contact cooling waters or rinses. 

Wet Air Pollution Control for Organic Constituents involves using water to remove organic 

constituents that are entrained in air streams exhausted from process tanks or production areas. 

Most frequently, wet air pollution control devices are used with cleaning and coating processes. 

A common type of wet air pollution control is the wet packed scrubber consisting of a spray 

chamber that is filled with packing material. Water is continuously sprayed onto the packing and 

the air stream is pulled through the packing by a fan. Pollutants in the air stream are absorbed by 

the water droplets and the air is released to the atmosphere. A single scrubber often serves 

numerous process tanks. 

4.2.2.2 Description of MP&M Metal-bearing Operations 

Abrasive Jet Machining includes removing stock material from a part by a high-speed stream of 

abrasive particles carried by a liquid or gas from a nozzle. Abrasive jet machining is used for 

deburring, drilling, and cutting thin sections of metal or composite material. Unlike abrasive 

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blasting, this process operates at pressures of thousands of pounds per square inch. The liquid 

streams typically are alkaline or emulsified oil solutions, although water also can be used. 

Acid Pickling Neutralization involves using a dilute alkaline solution to raise the pH of acid 

pickling rinse water that remains on the part after pickling. The wastewater from this operation is 

the acid pickling neutralization rinse water. 

Acid Treatment With Chromium is a general term used to describe any application of an acid 

solution containing chromium to a metal surface. Acid cleaning, chemical etching, and pickling 

are types of acid treatment. 

Chromic acid is used occasionally to clean cast iron, stainless steel, cadmium and aluminum, and 

bright dipping of copper and copper alloys. Also, chromic acid solutions can be used for the final 

step in acid cleaning phosphate conversion coating systems. Chemical conversion coatings 

formulated with chromic acid are defined at “Chromate Conversion Coating (or Chromating)” in 

this subsection. 

Wastewater generated during acid treatment includes spent solutions and rinse waters. Spent 

solutions typically are batch discharged and treated or disposed of off site. Most acid treatment 

operations are followed by a water rinse to remove residual acid. 

Acid Treatment Without Chromium is a general term used to describe any application of an 

acid solution not containing chromium to a metal surface. Acid cleaning, chemical etching, and 

pickling are types of acid treatment. 

Wastewater generated during acid treatment includes spent solutions and rinse waters. Spent 

solutions typically are batch discharged and treated or disposed of off site. Most acid treatment 

operations are followed by a water rinse to remove residual acid. 

Alcohol Cleaning involves removing dirt and residue material from a part using alcohol. 

Alkaline Cleaning Neutralization involves using a dilute acid solution to lower the pH of 

alkaline cleaning rinse water that remains on the part after alkaline cleaning. Wastewater from 

this operation is the alkaline cleaning neutralization rinse water. 

Alkaline Treatment With Cyanide is the cleaning of a metal surface with an alkaline solution 

containing cyanide. 

Wastewater generated during alkaline treatment includes spent solutions and rinse waters. 

Alkaline treatment solutions become contaminated from the introduction of soils and dissolution 

of the base metal. They usually are treated and disposed of on a batch basis. Alkaline treatment 

typically is followed by a water rinse that is discharged to a treatment system. 

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Anodizing With Chromium involves producing a protective oxide film on aluminum, 

magnesium, or other light metal, usually by passing an electric current through an electrolyte bath 

in which the metal is immersed. Anodizing may be followed by a sealant operation. 

Chromic acid anodic coatings have a relatively thick boundary layer and are more protective than 

are sulfuric acid coatings. For these reasons, chromic acid is sometimes used when the part 

cannot be rinsed completely. These oxide coatings provide corrosion protection, decorative 

surfaces, a base for painting and other coating processes, and special electrical and mechanical 

properties. 

Wastewaters generated during anodizing include spent anodizing solutions, sealants, and rinse 

waters. Because of the anodic nature of the process, anodizing solutions become contaminated 

with the base metal being processed. These solutions eventually reach an intolerable 

concentration of dissolved metal and require treatment or disposal. Rinse water following 

anodizing, coloring, and sealing typically is discharged to a treatment system. 

Anodizing Without Chromium involves applying a protective oxide film to aluminum, 

magnesium, or other light metal, usually by passing an electric current through an electrolyte bath 

in which the metal is immersed. Phosphoric acid, sulfuric acid, and boric acid are used in 

anodizing. Anodizing also may include sealant baths. These oxide coatings provide corrosion 

protection, decorative surfaces, a base for painting and other coating processes, and special 

electrical and mechanical properties. 

Wastewater generated during anodizing includes spent anodizing solutions, sealants, and rinse 

waters. Because of the anodic nature of the process, anodizing solutions become contaminated 

with the base metal being processed. These solutions eventually reach an intolerable 

concentration of dissolved metal and require treatment or disposal. Rinse water following 

anodizing, coloring, and sealing steps typically is discharged to a treatment systems. 

Carbon Black Deposition involves coating the inside of printed circuit board holes by dipping 

the circuit board into a tank that contains carbon black and potassium hydroxide. After excess 

solution dips from the circuit boards, they are heated to allow the carbon black to adhere to the 

board. 

Catalyst Acid Pre-Dip uses rinse water to remove residual solution from a part after the part is 

processed in an acid bath. The wastewater generated in this unit operation is the rinse water. 

Chemical Conversion Coating without Chromium is the process of applying a protective 

coating on the surface of a metal without using chromium. Such coatings are applied through 

phosphate conversion (except for “Iron Phosphate Conversion Coating,” see section 4.2.2.1), 

metal coloring, or passivation. Coatings are applied to a base metal or previously deposited metal 

to increase corrosion protection and lubricity, prepare the surface for additional coatings, or 

formulate a special surface appearance. This unit process includes sealant operations that use 

additives other than chromium. 

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� In phosphate conversion, coatings are applied for one or more of the 

following reasons: to provide a base for paints and other organic coatings; 

to condition surfaces for cold forming operations by providing a base for 

drawing compounds and lubricants; to impart corrosion resistance to the 

metal surface; or to provide a suitable base for corrosion-resistant oils or 

waxes. Phosphate conversion coatings are formed by immersing a metal 

part in a dilute solution of phosphoric acid, phosphate salts, and other 

reagents. 

� Metal coloring by chemical conversion coating produces a large group of 

decorative finishes. Metal coloring includes the formation of oxide 

conversion coatings. In this operation, the metal surface is converted into 

an oxide or similar metallic compound, giving the part the desired color. 

The most common colored finishes are used on copper, steel, zinc, and 

cadmium. 

� Passivation forms a protective coating on metals, particularly stainless 

steel, by immersing the part in an acid solution. Stainless steel is 

passivated to dissolve embedded iron particles and to form a thin oxide 

film on the surface of the metal. 

Wastewater generated during chemical conversion coating includes spent solutions and rinses 

(i.e., both the chemical conversion coating solutions and post-treatment sealant solutions). These 

solutions commonly are discharged to a treatment system when contaminated with the base metal 

or other impurities. Rinsing normally follows each process step, except when a sealant dries on 

the part surface. 

Chemical Milling (or Chemical Machining) involves removing metal from a part by controlled 

chemical attack, or etching, to produce desired shapes and dimensions. In chemical machining, a 

masking agent typically is applied to cover a portion of the part's surface; the exposed 

(unmasked) surface is then treated with the chemical machining solution. 

Wastewater generated during chemical machining includes spent solutions and rinses. Process 

solutions typically are discharged after becoming contaminated with the base metal. Rinsing 

normally follows chemical machining. 

Chromate Conversion Coating (or Chromating) involves forming a conversion coating 

(protective coating) on a metal by immersing or spraying the metal with a hexavalent chromium 

compound solution to produce a hexavalent or trivalent chromium compound coating. This also 

is known as chromate treatment, and is most often applied to aluminum, zinc, cadmium or 

magnesium surfaces. Sealant operations using chromium also are included in this unit operation. 

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4.0 - Industry Description 

Chromate solutions include two types: (1) those that deposit substantial chromate films on the 

substrate metal and are complete treatments themselves, and (2) those that seal or supplement 

oxide, phosphate, or other types of protective coatings. 

Wastewater generated during chromate conversion coating includes spent process solutions (i.e., 

both the chromate conversion coating solutions and post-treatment sealant solutions) and rinses. 

These solutions typically are discharged to a treatment system when contaminated with the base 

metal or other impurities. Also, chromium-based solutions, which are typically formulated with 

hexavalent chromium, lose operating strength when the hexavalent chromium reduces to trivalent 

chromium during use. Rinsing normally follows each process step, except for sealants that dry on 

the surface of the part. 

Chromium Drag-out Destruction is a unit operation performed following chromium-bearing 

operations to reduce hexavalent chromium that is “dragged out” of the process bath. Parts are 

dipped in a solution of a chromium-reducing chemical (e.g., sodium metabisulfite) to prevent the 

hexavalent chromium from contaminating subsequent process baths. This operation typically is 

performed in a stagnant drag-out rinse tank that contains concentrated chromium-bearing 

wastewater. 

Cyanide Drag-out Destruction involves dipping the part in a cyanide oxidation solution (e.g., 

sodium hypochloride) to prevent cyanide that is “dragged out” of a process bath from 

contaminating subsequent process baths. This operation typically is performed in a stagnant dragout rinse tank. 

Cyaniding Rinse is generated during cyaniding hardening of a part. The part is heated in a 

molten salt solution containing cyanide. Wastewater is generated when excess cyanide salt 

solution is removed from the part in rinse water. 

Electrochemical Machining is a process in which the part becomes the anode and a shaped 

cathode is the cutting tool. By pumping electrolyte between the electrodes and applying a current, 

metal is rapidly but selectively dissolved from the part. Wastewater generated during 

electrochemical machining includes spent electrolytes and rinses. 

Electroless Catalyst Solution involves adding a catalyst just prior to an electroless plating 

operation to accelerate the plating operation. 

Electroless Plating involves applying a metallic coating to a part using a chemical reduction 

process in the presence of a catalysis. An electric current is not used in this operations. The metal 

to be plated onto a part typically is held in solution at high concentrations using a chelating agent. 

This plates all areas of the part to a uniform thickness regardless of the configuration of the part. 

Also, an electroless-plated surface is dense and virtually nonporous. Copper and nickel 

electroless plating operations are the most common. 

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4.0 - Industry Description 

Sealant operations (i.e., other than hot water dips) following electroless plating are considered 

separate unit operations if they include any additives. 

Wastewater generated during electroless plating includes spent process solutions and rinses. The 

wastewater contains chelated metals, which require separate preliminary treatment to break the 

metal chelates prior to conventional chemical precipitation. Rinsing follows most electroless 

plating processes to remove residual plating solution and prevent contamination of subsequent 

process baths. 

Electrolytic Cleaning involves removing soil, scale, or surface oxides from a part by 

electrolysis. The part is one of the electrodes and the electrolyte is usually alkaline. Electrolytic 

alkaline cleaning and electrolytic acid cleaning are the two types of electrolytic cleaning. 

� Electrolytic alkaline cleaning produces a cleaner surface than do 

nonelectrolytic methods of alkaline cleaning. This operation uses strong 

agitation, gas evolution in the solution, and oxidation-reduction reactions 

that occur during electrolysis. In addition, dirt particles become electrically 

charged and are repelled from the part surface. 

� Electrolytic acid cleaning sometimes is used as a final cleaning before 

electroplating. Sulfuric acid is most frequently used as the electrolyte. As 

with electrolytic alkaline cleaning, the mechanical scrubbing effect from 

the evolution of gas enhances the effectiveness of the process. 

Wastewater generated during electrolytic cleaning includes spent process solutions and rinses. 

Electrolytic cleaning solutions become contaminated during use due to the dissolution of the base 

metal and the introduction of pollutants. The solutions typically are batch discharged for 

treatment or disposal after they weaken. Rinsing following electrolytic cleaning removes residual 

cleaner to prevent contamination of subsequent process baths. 

Electroplating with Chromium involves producing a chromium metal coating on a surface by 

electrodeposition. Electroplating provides corrosion protection, wear or erosion resistance, 

lubricity, electrical conductivity, or decoration. 

In electroplating, metal ions in acid, alkaline, or neutral solutions are reduced on the cathodic 

surfaces of the parts being plated. Metal salts or oxides typically are added to replenish the 

solutions. Chromium trioxide often is added as a source of chromium. 

In addition to water and the metal being deposited, electroplating solutions often contain agents 

that form complexes with the metal being deposited, stabilizers to prevent hydrolysis, buffers for 

pH control, catalysts to assist in deposition, chemical aids to dissolve anodes, and miscellaneous 

ingredients that modify the process to attain specific properties. Sealant operations performed 

after this operation are considered separate unit operations if they include any additives (i.e., 

other than hot water dips). 

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4.0 - Industry Description 

Wastewater generated during electroplating includes spent process solutions and rinses. 

Electroplating solutions occasionally become contaminated during use due to the base metal 

dissolving and the introduction of other pollutants, diminishing the effectiveness of the 

electroplating solutions. Spent concentrated solutions typically are treated to remove pollutants 

and reused, processed in a wastewater treatment system, or disposed of off site. Rinse waters, 

including some drag-out rinse tank solutions, typically are treated on site. 

Electroplating with Cyanide involves producing metal coatings on a surface by 

electrodeposition using cyanide. Electroplating provides corrosion protection, wear or erosion 

resistance, electrical conductivity, or decoration. 

In electroplating, metal ions in acid, alkaline, or neutral solutions are reduced on the cathodic 

surfaces of the parts being plated. The metal ions in solution typically are replenished by 

dissolving metal from anodes contained in inert wire or metal baskets. Sealant operations 

performed after this operation are considered separate unit operations if they include any 

additives (i.e., any sealant operations other than hot water dips). 

In addition to water and the metal being deposited, electroplating solutions often contain agents 

that form complexes with the metal being deposited, stabilizers to prevent hydrolysis, buffers to 

control pH, catalysts to assist in deposition, chemical aids to dissolve anodes, and miscellaneous 

ingredients that modify the process to attain specific properties. Cyanide, usually in the form of 

sodium or potassium cyanide, frequently is used as a complexing agent for zinc, cadmium, 

copper, and precious metal baths. 

Wastewater generated during electroplating includes spent process solutions and rinses. 

Electroplating solutions occasionally become contaminated during use due to dissolution of the 

base metal and the introduction of other pollutants, diminishing the performance of the 

electroplating solutions. Spent concentrated solutions typically are treated to remove pollutants 

and reused, processed in a wastewater treatment system, or disposed of off site. Rinse waters, 

including some drag-out rinse tank solutions, typically are treated on site. 

Electroplating without Chromium or Cyanide involves the production of metal coatings on a 

surface by electrodeposition, without using chromium or cyanide. Commonly electroplated 

metals include nickel, copper, tin/lead, gold, and zinc. Electroplating provides corrosion 

protection, wear or erosion resistance, lubricity, electrical conductivity, or decoration. 

In electroplating, metal ions in acid, alkaline, or neutral solutions are reduced on the cathodic 

surfaces of the parts being plated. The metal ions in solution typically are replenished by 

dissolving metal from anodes contained in inert wire or metal baskets. Sealant operations 

performed after this operation are considered separate unit operations if they include any 

additives (i.e., any sealant operations other than hot water dips). 

In addition to water and the metal being deposited, electroplating solutions often contain agents 

that form complexes with the metal being deposited, stabilizers to prevent hydrolysis, buffers to 

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4.0 - Industry Description 

control pH, catalysts to assist in deposition, chemical aids to dissolve anodes, and miscellaneous 

ingredients that modify the process to attain specific properties. 

Wastewater generated during electroplating without chromium or cyanide includes spent process 

solutions and rinses. Electroplating solutions occasionally become contaminated during use due 

to dissolution of the base metal and the introduction of other pollutants, diminishing the 

effectiveness of the electroplating solutions. Spent concentrated solutions typically are treated for 

pollutant removal and reused, processed in a wastewater treatment system, or disposed of off site. 

Rinse waters, including some drag-out rinse tank solutions, typically are treated on site. 

Electropolishing involves producing a highly polished surface on a part using reversed 

electrodeposition in which the anode (part) releases some metal ions into the electrolyte to reduce 

surface roughness. When current is applied, a polarized film forms on the metal surface, through 

which metal ions diffuse. In this operation, areas of surface roughness on parts serve as highcurrent density areas and are dissolved at rates greater than the rates for smoother portions of the 

metal surface. 

Metals are electropolished to improve appearance, reflectivity, and corrosion resistance. Base 

metals processed by electropolishing include aluminum, copper, zinc, low-alloy steel, and 

stainless steel. Common electrolytes include sodium hydroxide and combinations of sulfuric 

acid, phosphoric acid, and chromic acid. 

Wastewater generated during electropolishing includes spent process solutions and rinses. 

Eventually, the concentration of dissolved metals increases to the point where the process 

becomes ineffective. Typically, a portion of the bath is decanted and either fresh chemicals are 

added or the entire solution is discharged to treatment and replaced with fresh chemicals. Rinsing 

can involve several steps and can include hot immersion or spray rinses. 

Galvanizing/Hot Dip Coating involves using various processes to coat an iron or steel surface 

with zinc. In hot dipping, a base metal is coated by dipping it into a tank that contains a molten 

metal. 

Hot Dip Coating involves applying a metal coating (usually zinc) to the surface of a part by 

dipping the part in a molten metal bath. Wastewater is generated in this operation when residual 

metal coating solution is removed from the part in rinse water. 

Kerfing uses a tool to remove small amounts of metal from a product surface. Water and 

synthetic coolants may be used to lubricate the area between the tool and the metal, to maintain 

the temperature of the cutting tool, and to remove metal fines from the surface of the part. This 

operation generates oily wastewater that contains metal fines and dust. 

Laminating involves applying a material to a substrate using heat and pressure. 

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4.0 - Industry Description 

Mechanical and Vapor Plating involves applying a metallic coating to a part. For mechanical 

plating, the part is rotated in a drum containing a water-based solution, glass beads, and metal 

powder. In vapor plating, a metallic coating is applied by atomizing the metal and applying an 

electric charge to the part, which causes the atomized (vapor phase) metal to adhere to the part. 

Wastewater generated in this operation includes spent solutions from the process bath and rinse 

water. Typically, the wastewater contains high concentrations of the applied metal. 

Metallic Fiber Cloth Manufacturing involves weaving thin metallic fibers to create a mesh 

cloth. 

Metal Spraying (Including Water Curtain) involves applying a metallic coating to a part by 

projecting molten or semimolten metal particles onto a substrate. Coatings can be sprayed from 

rod or wire stock or from powdered material. The process involves feeding the material (e.g., 

wire) into a flame where it is melted. The molten stock then is stripped from the end of the wire 

and atomized by a high-velocity stream of compressed air or other gas that propels the material 

onto a prepared substrate or part. 

Metal spraying coatings are used in a wide range of special applications, including: insulating 

layers in applications such as induction heating coils; electromagnetic interference shielding; 

thermal barriers for rocket engines; nuclear moderators; films for hot isostatic pressing; and 

dimensional restoration of worn parts. 

Metal spraying is sometimes performed in front of a “water curtain” (a circulated water stream 

used to trap overspray) or a dry filter exhaust hood that captures the overspray and fumes. With 

water curtain systems, water is recirculated from a sump or tank. Wastewater is generated when 

the sump or tank is discharged periodically. Metal spraying typically is not followed by rinsing. 

Painting-Immersion (Including Electrophoretic, “E-coat”) involves applying an organic 

coating to a part using processes such autophoretic and electrophoretic painting. 

� Autophoretic Painting involves applying an organic paint film by 

electrophoresis when a part is immersed in a suitable aqueous bath. 

� Electrophoretic Painting is coating a part by making it either anodic or 

cathodic in a bath that is generally an aqueous emulsion of the organic 

coating material. 

� Other Immersion Painting includes all other types of immersion painting 

such as dip painting. 

Water is used in immersion paint operations as a carrier for paint particles and to rinse the part. 

Aqueous painting solutions and rinses typically are treated through an ultrafiltration system. The 

concentrate is returned to the painting solution, and the permeate is reused as rinse water. Sites 

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4.0 - Industry Description 

typically discharge a bleed stream to treatment. The painting solution and rinses are batch 

discharged periodically to treatment. 

Photo Imaging is the process of exposing a photoresist-laden printed wiring board to light to 

impact the circuitry design to the board. Water is not used in this operation. 

Photo Image Developing is an operation in which a water-based solution is used to develop the 

exposed circuitry in a photoresist-laden printed wiring board. Wastewater generated in this 

operation includes spent process solution and rinse water. 

Photoresist Application is an operation that uses heat and pressure to apply a photoresist coating 

to a printed wiring board. Water is not used in this operation. 

Photoresist Strip involves removing organic photoresist material from a printed wiring board 

using an acid solution. 

Phosphor Deposition is the application of a phosphorescent coating to a part. Wastewater 

generated in this unit operation includes water used to keep the parts clean and wet while the 

coating is applied, and rinse water used to remove excess phosphorescent coating from the part. 

Physical Vapor Deposition involves physically removing a material from a source through 

evaporation or sputtering, using the energy of the vapor particles in a vacuum or partial vacuum to 

transport the removed material, and condensing the removed material as a film onto the surface of 

a part or other substrate. 

Plasma Arc Machining involves removing material or shaping a part by a high-velocity jet of 

high-temperature, ionized gas. A gas (nitrogen, argon, or hydrogen) is passed through an electric 

arc, causing the gas to become ionized, and heated to temperatures exceeding 16,650°C 

(30,000°F). The relatively narrow plasma jet melts and displaces the material in its path. Because 

plasma arc machining does not depend on a chemical reaction between the gas and the part, and 

because plasma temperatures are extremely high, the process can be used on almost any metal, 

including those that are resistant to oxygen-fuel gas cutting. The method is used mainly for profile 

cutting of stainless steel and aluminum alloys. 

Although plasma arc machining typically is a dry process, water is used for water injection plasma 

arc torches. In these cases, a constricted swirling flow of water surrounds the cutting arc. This 

operation also may be performed immersed in a water bath. In both cases, water is used to 

stabilize the arc, to cool the part, and to contain smoke and fumes. 

Plastic Wire Extrusion involves applying a plastic material to a metal wire through an extrusion 

process. 

Salt Bath Descaling involves removing surface oxides or scale from a part by immersing the part 

in a molten salt bath or hot salt solution. Salt bath descaling solutions can contain molten salts, 

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4.0 - Industry Description 

caustic soda, sodium hydride, and chemical additives. Molten salt baths are used in a salt bathwater quench-acid dip sequence to remove oxides from stainless steel and other corrosionresistant alloys. In this process, the part typically is immersed in the molten salt, quenched with 

water, and then dipped in acid. Oxidizing, reducing, or electrolytic salt baths can be used 

depending on the oxide to be removed. Wastewater generated during salt bath descaling includes 

spent process solutions, quenches, and rinses. 

Shot Tower - Lead Shot Manufacturing involves dropping molten lead from a platform on the 

top of a tower through a sieve-like device and into a vat of cold water. 

Soldering involves joining metals by inserting a thin (capillary thickness) layer of nonferrous 

filler metal into the space between them. Bonding results from the intimate contact produced by 

the metallic bond formed between the substrate metal and the solder alloy. The term soldering is 

used where the melting temperature of the filler is below 425°C (800°F). Some soldering 

operations use a solder flux, which is an aqueous or nonaqueous material used to dissolve, 

remove, or prevent the formation of surface oxides on the part. 

Except for the use of aqueous fluxes, soldering typically is a dry operation; however, a quench or 

rinse sometimes follows soldering to cool the part or remove excess flux or other foreign material 

from its surface. Recent developments in soldering technology have focused on fluxless solders 

and fluxes that can be cleaned off with water. 

Solder Flux Cleaning involves removing residual solder flux from a printed circuit board using 

either an alkaline or alcohol cleaning solution. 

Solder Fusing involves coating a tin-lead plated circuit board with a solder flux and then passing 

the board through a hot oil. The hot oil fuses the tin-lead to the board and creates a solder-like 

finish on the board. 

Solder Masking involves applying a resistive coating to certain areas of a circuit board to protect 

the areas during subsequent processing. 

Sputtering is a vacuum evaporation process in which portions of a coating material are physically 

removed from a substrate and deposited a thin film onto a different substrate. 

Stripping (Paint) involves removing a paint (or other organic) coating from a metal basis 

material. Stripping commonly is performed as part of the manufacturing process to recover parts 

that have been improperly coated or as part of maintenance and rebuilding to restore parts to a 

usable condition. 

Organic coatings (including paint) are stripped using thermal, mechanical, and chemical means. 

Thermal methods include burn-off ovens, fluidized beds of sand, and molten salt baths. 

Mechanical methods include scraping and abrasive blasting (as defined in “Abrasive Blasting” in 

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4.0 - Industry Description 

Section 4.2.2.1). Chemical paint strippers include alkali solutions, acid solutions, and solvents 

(e.g., methylene chloride). 

Wastewater generated during organic coating stripping includes process solutions (limited mostly 

to chemical paint strippers and rinses). 

Stripping (Metallic Coating) involves removing a metallic coating from a metal basis material. 

Stripping is commonly part of the manufacturing process to recover parts that have been 

improperly coated or as part of maintenance and rebuilding to restore parts to a usable condition. 

Metallic coating stripping most often uses chemical baths, although mechanical means (e.g., 

grinding, abrasive blasting) also are used. Chemical stripping frequently is performed as an 

aqueous electrolytic process. 

Wastewater generated during metallic coating stripping includes process solutions and rinses. 

Stripping solutions become contaminated from dissolution of the base metal. Typically, the entire 

solution is discharged to treatment. Rinsing is used to remove the corrosive film remaining on the 

parts. 

Thermal Infusion uses heat to infuse metal powder or dust onto the surface of a part. Typically, 

thermal infusion is a dry operation. In some cases, however, water may be used to remove excess 

metal powder, metal dust, or molten metal. 

Ultrasonic Machining involves forcing an abrasive liquid between a vibrating tool and a part. 

Particles in the abrasive liquid strike the part, removing any microscopic flakes on the part. 

Vacuum Impregnation is used to reduce the porosity of the part. A filler material (usually 

organic) is applied to the surface of the part and polymerized under pressure and heat. Wastewater 

is generated in this unit operation when rinse water is used to remove residual organic coating 

from the part. 

Vacuum Plating involves applying a thin layer of metal oxide onto a part using molten metal in a 

vacuum chamber. 

Water Shedder involves applying a dilute water-based chemical compound to a part to accelerate 

drying. This operation typically is used to prevent a part from streaking when excess water 

remains on the part. 

Wet Air Pollution Control involves using water to remove chemicals, fumes, or dusts that are 

entrained in air streams exhausted from process tanks or production areas. Most frequently, wet 

air pollution control devices are used with electroplating, cleaning, and coating processes. A 

common type of wet air pollution control is the wet packed scrubber consisting of a spray 

chamber that is filled with packing material. Water is continuously sprayed onto the packing and 

the air stream is pulled through the packing by a fan. Pollutants in the air stream are absorbed by 

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4.0 - Industry Description 

the water droplets and the air is released to the atmosphere. A single scrubber often serves 

numerous process tanks; however, the air streams typically are segregated by source into 

chromium, cyanide, and acid/alkaline sources. Wet air pollution control can be divided into 

several suboperations, including: 

� Wet Air Pollution Control for Acid Alkaline Baths; 

� Wet Air Pollution Control for Cyanide Baths; 

� Wet Air Pollution Control for Chromium-Bearing Baths; and 

� Wet Air Pollution Control for Fumes and Dusts. 

Wire Galvanizing Flux involves using flux to remove rust and oxide from the surface of steel 

wire prior to galvanizing. This provides long-term corrosion protection for the steel wire. 

4.2.3 Metals Processed 

MP&M facilities perform proposed MP&M operations on a variety of metals. 

EPA identified 29 different metals processed at MP&M facilities from survey results. Of these, 

iron, aluminum, and copper are the metals most frequently processed. Nickel, tin, lead, gold, and 

zinc frequently are used in electroplating operations. 

Many MP&M facilities process more than one metal. Figure 4-7 shows the 

percentage of wastewater-discharging MP&M facilities by number of metals processed. As 

shown in Figure 4-7, 65 percent of the wastewater-discharging MP&M facilities that provided 

metal use information process more than one metal. 

4.2.4 Estimated Annual Wastewater Discharge 

Process wastewater is generated in many of the proposed MP&M operations listed 

in Section 4.2.2. Some operations may be performed with or without water (wet or dry) 

depending on the purpose of the operation, raw materials used, and final product use. For 

example, some machining operations (e.g., drilling) are performed without a coolant, while other 

machining operations (e.g., milling) require a coolant. Process wastewater may be recirculated, 

recycled or reused as described in Section 4.1.4; however, process wastewater generally is 

discharged to a treatment system or disposed of through other means (e.g., transfer to CWT). 

Based on survey results, the most commonly performed wet proposed MP&M 

operations are floor cleaning and acid treatment. Survey results also show the most commonly 

performed proposed MP&M operations do not generate the largest volumes of wastewater. Of the 

volume of wastewater discharged, 79 percent is generated from rinses, with chemical conversion 

coating rinsing, acid treatment rinsing, and alkaline treatment rinsing generating the highest 

volume of wastewater. Table 4-5 lists the proposed MP&M operations and presents the estimated 

number of MP&M facilities that discharge wastewater generated in each proposed MP&M 

operation and the estimated annual discharge for the proposed MP&M operation. Note that 

MP&M facilities typically conduct more than one proposed MP&M operation. 

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4.0 - Industry Description 

Five or M ore M etal Ty pes 

36% 

7% 

Three M etal Types 

22% 

F our M e ta l Ty pe s 

12% On e M e t a l Ty p e 

Two M etal Ty pes 

24% 

Source: MP&M Survey Database. 

Note:	 Although there are 44,000 wastewater-discharging MP&M facilities only 15,470 are 

represented in the above pie chart. The 1996 short and municipality surveys did not 

request metal use information. Additionally, several 1989 and 1996 long survey recipients 

did not provide this information. 

Figure 4-7. Percentage of Wastewater-Discharging MP&M facilities 

by Number of Metal Processed 

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4.0 - Industry Description 

Table 4-5 

Estimated Number of MP&M Facilities Discharging Process Wastewater 

by Proposed MP&M Operation and Estimated Annual Dischargea 

for Each Proposed MP&M Operation 

Survey Unit 

Operation 

Number Unit Operation 

Estimated Number of MP&M 

Facilities Discharging 

Wastewater from Unit 

Operation 

Estimated Annual 

Dischargeb 

(gpy) 

1 Abrasive Blasting 1,140 38,136,192 

1R. Abrasive Blasting Rinse 2,714 294,364,698 

2 Abrasive Jet Machining 1,802 32,882,557 

3 Acid Treatment With Chromium 789 4,119,176 

3R. Acid Treatment With Chromium Rinse 1,139 514,116,041 

4 Acid Treatment Without Chromium 21,518 307,274,559 

4R. Acid Treatment Without Chromium 

Rinse 

25,886 9,877,473,513 

5 Alkaline Cleaning for Oil Removal 15,194 1,017,415,369 

5R. Alkaline Cleaning for Oil Removal 

Rinse 

10,918 7,007,305,341 

6 Alkaline Treatment With Cyanide 447 4,260,538 

6R. Alkaline Treatment With Cyanide 

Rinse 

529 43,781,206 

7 Alkaline Treatment Without Cyanide 16,200 276,426,070 

7R. Alkaline Treatment Without Cyanide 

Rinse 

12,937 4,782,461,104 

8 Anodizing With Chromium 275 271,552 

8R. Anodizing With Chromium Rinse 358 145,962,877 

9 Anodizing Without Chromium 1,090 5,430,253 

9R. Anodizing Without Chromium Rinse 1,587 1,303,183,805 

10 Aqueous Degreasing 41,220 669,348,451 

10R. Aqueous Degreasing Rinse 28,923 517,175,686 

11 Assembly/Disassembly 2,031 18,107,602 

11R. Assembly/Disassembly Rinse 2,189 796,489 

12 Barrel Finishing 14,632 640,037,840 

12R. Barrel Finishing Rinse 6,694 539,294,744 

13 Burnishing 4,920 132,891,318 

13R. Burnishing Rinse 2,881 326,955,097 

14 Chemical Conversion Coating Without 

Chromium 

9,357 564,137,211 

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4.0 - Industry Description 

Table 4-5 (Continued) 

Survey Unit 

Operation 

Number Unit Operation 

Estimated Number of MP&M 

Facilities Discharging 

Wastewater from Unit 

Operation 

Estimated Annual 

Dischargeb 

(gpy) 

14R. Chemical Conversion Coating Without 

Chromium Rinse 

11,582 6,042,069,830 

15 Chemical Milling 1,466 41,355,172 

15R. Chemical Milling Rinse 2,323 645,522,600 

16 Chromate Conversion Coating 5,071 54,795,746 

16R. Chromate Conversion Coating Rinse 5,980 1,707,025,516 

17 Corrosion Preventive Coating 2,262 41,326,563 

17R. Corrosion Preventive Coating Rinse 1,015 287,465,378 

18 Electrical Discharge Machining 1,323 934,885 

18R. Electrical Discharge Machining Rinse 559 3,368,479 

19 Electrochemical Machining 294 329,427,414 

19R. Electrochemical Machining Rinse 258 34,587,020 

20 Electroless Plating 2,583 18,034,222 

20R. Electroless Plating Rinse 3,664 565,437,766 

21 Electrolytic Cleaning 5,280 33,756,614 

21R. Electrolytic Cleaning Rinse 6,886 1,501,249,740 

22 Electroplating With Chromium 1,019 37,242,632 

22R. Electroplating With Chromium Rinse 1,937 678,282,897 

23 Electroplating With Cyanide 1,958 38,162,499 

23R. Electroplating With Cyanide Rinse 8,885 686,691,868 

24 Electroplating Without Chromium or 

Cyanide 

4,558 92,968,816 

24R. Electroplating Without Chromium or 

Cyanide Rinse 

13,644 3,778,033,165 

25 Electropolishing 442 633,484 

25R. Electropolishing Rinse 458 70,178,477 

26 Floor Cleaning 49,002 797,062,121 

26R. Floor Cleaning Rinse 3,580 45,391,545 

27 Grinding 8,738 169,740,183 

27R. Grinding Rinse 263 72,465,147 

28 Heat Treating 1,609 156,660,147 

28R. Heat Treating Rinse 1,315 2,186,067,713 

29 Impact Deformation 404 40,582,591 

29R. Impact Deformation Rinse 148 8,237,308 

30 Machining 16,935 585,628,906 

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4.0 - Industry Description 

Table 4-5 (Continued) 

Survey Unit 

Operation 

Number Unit Operation 

Estimated Number of MP&M 

Facilities Discharging 

Wastewater from Unit 

Operation 

Estimated Annual 

Dischargeb 

(gpy) 

30R. Machining Rinse 683 149,922,705 

31 Metal Spraying 91 866,823,774 

32 Painting - Spray or Brush 2,303 3,009,847,635 

32R. Painting - Spray or Brush Rinse 688 726,589,166 

33 Painting - Immersion 450 164,139,746 

33R. Painting - Immersion Rinse 404 190,487,578 

34 Plasma Arc Machining 547 10,728,876 

35 Polishing 1,111 113,097,868 

35R. Polishing Rinse 2,745 567,887,844 

36 Pressure Deformation 520 241,040,874 

36R. Pressure Deformation Rinse 249 783,831,607 

37 Salt Bath Descaling 99 62,703 

37R. Salt Bath Descaling Rinse 111 53,938,360 

38 Soldering/Brazing 1,258 425,688,291 

38R. Soldering/Brazing Rinse 4,905 231,488,012 

39 Solvent Degreasingc 2,288 8,128,901 

39R. Solvent Degreasing Rinse 824 108,089,561 

40 Stripping (paint) 1,730 68,326,631 

40R. Stripping (paint) Rinse 2,720 295,059,493 

41 Stripping (metallic coating) 2,929 5,855,277 

41R. Stripping (metallic coating) Rinse 3,867 943,853,805 

42 Testing 5,947 3,713,880,058 

42R. Testing Rinse 1,093 46,615,860 

43 Thermal Cutting 228 35,395,401 

43R. Thermal Cutting Rinse 64 2,940,934 

44 Washing Finished Products 17,276 1,975,525,613 

44R. Washing Finished Products Rinse 5,378 651,385,578 

45 Welding 1,003 1,177,301,469 

45R. Welding Rinse 360 44,297,886 

46AA Wet Air Pollution Control for Acid 

Alkaline Baths 

2,726 1,335,631,480 

46CN Wet Air Pollution Control for Cyanide 

Baths 

189 43,321,771 

46CR Wet Air Pollution Control for 

Chromium-Bearing Baths 

942 234,814,961 

4-38

4.0 - Industry Description 

Table 4-5 (Continued) 

Survey Unit 

Operation 

Number Unit Operation 

Estimated Number of MP&M 

Facilities Discharging 

Wastewater from Unit 

Operation 

Estimated Annual 

Dischargeb 

(gpy) 

46FD Wet Air Pollution Control for Fumes 

and Dusts 

657 30,596,886 

46OR Wet Air Pollution Control for Organic 

Constituents 

347 19,613,181 

50 Carbon Black Deposition 20 31,848 

50R. Carbon Black Deposition Rinse 43 2,377,389 

51 Bilge Water 11 69,949,548 

51R. Bilge Water Rinse 8 304,839 

54R. Galvanizing/Hot Dip Coating Rinse 69 225,928,671 

56 Mechanical Plating 246 27,717,634 

56R. Mechanical Plating Rinse 240 202,002,940 

57 Photo Image Developing 1,456 430,595,569 

57R. Photo Image Developing Rinse 1,531 603,943,807 

58 Photo Imaging 9 27,900 

58R. Photo Imaging Rinse 9 497,022 

59 Photoresist Applications 15 7,157 

59R. Photoresist Applications Rinse 17 180,161 

62 Solder Flux Cleaning 99 1,694,799 

62R. Solder Flux Cleaning Rinse 461 214,927,721 

63 Solder Fusing 27 5,739,846 

63R. Solder Fusing Rinse 280 55,114,403 

65 Steam Cleaning 26 18,130,100 

65R. Steam Cleaning Rinse 16 15,851,628 

66 Vacuum Impregnation 8 649,893 

66R. Vacuum Impregnation Rinse 98 10,144,137 

70 Kerfing 30 7,429,800 

71 Adhesive Bonding 186 525,950 

72 Calibration 55 2,467 

73R. Cyanide Rinsing Rinse 22 33,490 

74 Hot Dip Coating 9 692 

74R. Hot Dip Coating Rinse 75 28,135,640 

76 Thermal Infusion 62 138,939 

78 Phosphor Deposition 11 4,283 

78R. Phosphor Deposition Rinse 11 42,826 

80 Chromium Drag-out Reduction 8 857,994 

4-39

4.0 - Industry Description 

Table 4-5 (Continued) 

Survey Unit 

Operation 

Number Unit Operation 

Estimated Number of MP&M 

Facilities Discharging 

Wastewater from Unit 

Operation 

Estimated Annual 

Dischargeb 

(gpy) 

83 Acid Pickling Neutralization 8 22,761 

83R. Acid Pickling Neutralization Rinse 16 22,497,118 

87 Tin Catalyst 385 295,415 

87R. Tin Catalyst Rinse 468 102,883,125 

88 Catalyst Acid Pre-Dip 961 680,949 

88R. Catalyst Acid Pre-Dip Rinse 1,108 64,173,379 

90 Photoresist Strip 439 8,039,179 

90R. Photoresist Strip Rinse 732 312,703,073 

Source: MP&M Survey Database.
 a

EPA used MP&M survey information to generate the estimated facility counts and estimated annual discharge.
 b

These totals do not include facilities generating process wastewater that is contract hauled off site or not discharged.
 c

Solvent degreasing operations that use process water are included under alkaline treatment (see unit operation 5).


4-40

4.0 - Industry Description 

4.3 Trends in the Industry 

To develop the MP&M rule, EPA collected data from the MP&M industry for over 

10 years, including detailed information from surveys in 1990, 1996, and 1997. Survey data and 

results of industry site visits and sampling episodes showed numerous changes in the industry 

between 1990 and 1996. Survey data indicate a greater than 30-percent industry increase in the 

use of wastewater treatment systems between 1990 and 1996. Many facilities also have begun to 

implement advanced treatment systems that include ultrafiltration for increased organic pollutant 

removal and microfiltration units to improve clarification. The MP&M survey database indicates 

that in 1990, 260 of the MP&M facilities with wastewater treatment in place were using 

membrane filtration. By 1996, that number increased to 700. In addition, facilities are moving 

toward greater implementation of pollution prevention and water reduction, including progression 

to zero discharge when possible. Fifty-three percent currently have in-process pollution 

prevention or water use reduction practices in place, and over 27 percent of discharging facilities 

report having wet unit operations with zero discharge. Improvements in treatment controls are 

allowing for more automated process controls, which leads to more consistent wastewater 

treatment. Advances in wastewater treatment chemicals also result in higher treatment 

efficiencies. 

4.4 References 

1.	 Cubberly, William H. (ed.). Tool and Manufacturing Engineers Handbook, Desk 

Edition. Society of Manufacturing Engineers, Dearborne, MI, 1989. 

2. Detrisac, M. Arthur. "Treatable Cleaners," Metal Finishing. September 1991. 

3.	 U.S. Environmental Protection Agency. Development Document for Effluent 

Limitations Guidelines and Standards for the Metal Finishing Point Source 

Category. EPA 440/1-83/091, June 1983. 

4.	 Mohler, J.B. "Alkaline Cleaning for Electroplating," Metal Finishing. September 

1984. 

5.	 Wood, William G. (Coordinator). The New Metals Handbook, Vol. 5. Surface 

Cleaning, Finishing, and Coating. American Society for Metals, May 1990. 

6.	 Lowenheim, Frederick A. Electroplating Fundamentals of Surface Finishing. 

McGraw-Hill Book Company, New York, NY, 1978. 

7.	 Murphy, Michael (ed.). Metal Finishing Guidebook and Directory Issue '93, Metal 

Finishing. January 1993. 

4-41

5.0 - Wastewater Characteristics 

5.0 WASTEWATER CHARACTERISTICS 

This section summarizes the characteristics of wastewater generated by oily 

operations (as defined in Section 1.0) and discharged to wastewater treatment systems at MP&M 

facilities. In general, the MP&M industry generates oil- and organic pollutant-bearing 

wastewater. This wastewater exhibits high concentrations of oil and concentrations of organic 

pollutants. Oil-bearing wastewater is classified as containing either free (floating) oils or 

oil/water emulsions. These wastewaters may also contain incidental levels of metals most often 

in the suspended or particulate phase. 

Analytical data from the MP&M sampling program, including data obtained from 

sanitation districts, MP&M facilities, and MP&M industry trade associations, are in the sampling 

episode reports located in Sections 5.2 and 15.3 of the rulemaking record. As part of the MP&M 

rulemaking, EPA also evaluated the following wastewaters: (1) hexavalent chromium-bearing 

wastewater; (2) cyanide-bearing wastewater; (3) chelated metal-bearing wastewater; and (4) 

metal-bearing wastewater. These additional analyses are presented in Appendix C. 

This section summarizes analytical data obtained during the MP&M regulatory 

development process for oily operations and influents to the wastewater treatment systems. 

These subsections present the number of samples analyzed, the number of times each pollutant 

was detected, and the minimum, maximum, mean, and median pollutant concentrations. Section 

5.1 discusses the oily operations that generate oil-bearing and organic pollutant-bearing 

wastewater and presents pollutant concentration data for the process waters and rinse waters for 

those oily operations. Section 5.2 characterizes the influent to oily wastewater treatment 

systems. 

5.1 Process Water and Rinse Water 

Table 5-1 lists the oily operations that generate oil-bearing and organic pollutantbearing wastewater and presents the number of process water and rinse water samples collected 

for each operation during EPA’s sampling program. Section 4.0 describes these operations in 

detail. 

MP&M facilities usually use oil/water emulsions as coolants and lubricants in 

machining, grinding, and deformation operations. These facilities also perform alkaline cleaning 

operations to remove oil and grease from parts. Table 5-2 summarizes the pollutant 

concentration data collected during the MP&M sampling program for process water from oily 

operations that generate oil-bearing wastewater. Table 5-3 summarizes similar data for the 

associated rinse waters. The maximum concentration of oil and grease (measured as hexane 

extractable material (HEM)) in the process water samples was 390,000 mg/L (from an alkaline 

cleaning bath), while the maximum concentration of oil and grease in the rinse water samples 

was 9,195 mg/L. 

5-1

5.0 - Wastewater Characteristics 

Table 5-1


Number of Process Water and Rinse Water Samples For Oily Operations


Unit Operation 

No. of Process 

Water Samplesa 

No. of Rinse Water 

Samplesa 

Abrasive Blasting 

Adhesive Bonding 

Alkaline Cleaning for Oil Removal 

Alkaline Treatment without Cyanide 

Aqueous Degreasing 

Corrosion Preventive Coating 

Electrical Discharge Machining 

Floor Cleaning (In Process Area) 

Grinding 

Heat Treating 

Impact Deformation 

Machining 

Painting-spray or Brush (Including Water Curtains) 

Steam Cleaning 

Testing (e.g., Hydrostatic, Dye Penetrant, Ultrasonic, Magnetic Flux) 

Thermal Cutting 

Tumbling/Barrel Finishing/Mass Finishing/Vibratory Finishing 

Washing (Finished Products) 

Welding 

Wet Air Pollution Control for Organic Constituents 

3 

0 

34 

18 

11 

8 

1 

6 

19 

3 

1 

14 

6 

8 

8 

2 

9 

4 

0 

0b 

3 

0 

42 

32 

6 

4 

0 

0 

0 

7 

0 

0 

0 

0 

3 

0 

4 

3 

1 

0b 

Source: MP&M Sampling Program.
 a

Oily operations for which no samples were collected are rarely performed or were not observed at MP&M facilities. 
 b

Data were transferred for this operation.


NA - Not applicable; unit operation has no associated rinse.


5-2

5.0 - Wastewater Characteristics 

Table 5-2


Process Water Pollutant Concentration Data for Oily Operations


Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants 

1,1,1-Trichloroethane 76 1 0.011 0.011 0.011 0.011 

1,1-Dichloroethane 76 0 NA NA NA NA 

1,1-Dichloroethene 76 0 NA NA NA NA 

2,4-Dimethylphenol 71 5 0.016 0.064 0.052 0.062 

2,4-Dinitrophenol 75 0 NA NA NA NA 

2,6-Dinitrotoluene 75 0 NA NA NA NA 

2-Nitrophenol 76 0 NA NA NA NA 

4-Chloro-3-Methylphenol 75 11 0.011 91.1 18.2 0.587 

4-Nitrophenol 74 1 0.424 0.424 0.424 0.424 

Acenaphthene 76 0 NA NA NA NA 

Acrolein 73 1 0.161 0.161 0.161 0.161 

Anthracene 76 1 0.193 0.193 0.193 0.193 

Bis(2-ethylhexyl) Phthalate 76 18 0.015 143 8.65 0.164 

Butyl Benzyl Phthalate 76 1 0.066 0.066 0.066 0.066 

Chlorobenzene 76 1 0.028 0.028 0.028 0.028 

Chloroethane 76 1 8.34 8.34 8.34 8.34 

Chloroform 76 5 0.010 0.019 0.014 0.013 

Di-n-butyl Phthalate 75 3 0.012 0.070 0.033 0.018 

Di-n-octyl Phthalate 75 1 0.020 0.020 0.020 0.020 

Dimethyl Phthalate 75 0 NA NA NA NA 

Ethylbenzene 76 4 0.028 0.594 0.239 0.167 

Fluoranthene 76 4 0.029 0.243 0.132 0.129 

Fluorene 75 2 0.010 0.021 0.015 0.015 

Isophorone 75 0 NA NA NA NA 

Methylene Chloride 76 3 0.028 6.76 2.27 0.030 

n-Nitrosodimethylamine 75 0 NA NA NA NA 

n-Nitrosodiphenylamine 76 1 0.025 0.025 0.025 0.025 

5-3

5.0 - Wastewater Characteristics 

Table 5-2 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants (continued) 

Naphthalene 76 4 0.025 1.84 0.511 0.091 

Phenanthrene 76 4 0.101 5.50 1.47 0.143 

Phenol 76 21 0.012 8.84 1.28 0.103 

Pyrene 76 0 NA NA NA NA 

Tetrachloroethene 76 2 0.015 0.021 0.018 0.018 

Toluene 76 6 0.029 0.653 0.183 0.103 

Trichloroethene 75 10 0.019 2.29 0.251 0.023 

Metal Priority Pollutants 

Antimony 149 49 0.003 1.93 0.217 0.042 

Arsenic 150 66 0.001 1.65 0.183 0.023 

Beryllium 150 24 0.0005 0.025 0.004 0.002 

Cadmium 154 78 0.002 12.6 1.23 0.088 

Chromium 154 121 0.007 995 11.7 0.128 

Copper 154 142 0.006 190 6.40 0.695 

Lead 154 87 0.006 7,150 91.9 0.414 

Mercury 150 33 0.0001 0.017 0.001 0.0005 

Nickel 154 113 0.008 80.9 2.24 0.141 

Selenium 149 41 0.001 1.57 0.087 0.024 

Silver 154 48 0.001 2.12 0.138 0.014 

Thallium 149 22 0.001 0.113 0.023 0.021 

Zinc 154 145 0.008 1,160 27.2 1.31 

Conventional Pollutants 

BOD 5-day (Carbonaceous) 65 54 3.00 64,900 3,953 837 

Oil and Grease (as HEM) 102 83 1.08 390,000 13,884 390 

Total Suspended Solids 153 140 4.00 110,000 2,764 172 

Nonconventional Organic Pollutants 

1,4-Dioxane 76 2 0.077 1.00 0.539 0.589 

1-Bromo-2-Chlorobenzene 76 0 NA NA NA NA 

1-Bromo-3-Chlorobenzene 76 0 NA NA NA NA 

1-Methylfluorene 76 3 0.014 2.60 0.912 0.123 

1-Methylphenanthrene 76 3 0.122 5.65 1.97 0.147 

5-4

5.0 - Wastewater Characteristics 

Table 5-2 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

2-Butanone 76 13 0.057 38.3 3.72 0.121 

2-Hexanone 76 3 0.124 0.505 0.263 0.161 

2-Isopropylnaphthalene 76 1 7.34 7.34 7.34 7.34 

2-Methylnaphthalene 76 9 0.011 3.14 0.511 0.236 

2-Propanone 76 41 0.050 11.9 0.943 0.215 

3,6-Dimethylphenanthrene 76 1 8.50 8.50 8.50 8.50 

4-Methyl-2-Pentanone 76 10 0.052 63.7 6.73 0.358 

Acetophenone 76 1 0.566 0.566 0.566 0.566 

Alpha-terpineol 72 12 0.012 14.1 2.69 178 

Aniline 76 0 NA NA NA NA 

Benzoic Acid 76 11 0.071 13.2 1.48 0.189 

Benzyl Alcohol 76 2 0.094 0.208 0.151 0.151 

Biphenyl 76 2 0.014 0.038 0.026 0.026 

Carbon Disulfide 76 0 NA NA NA NA 

Dibenzofuran 76 0 NA NA NA NA 

Dibenzothiophene 76 0 NA NA NA NA 

Diphenyl Ether 76 0 NA NA NA NA 

Diphenylamine 76 2 0.024 0.026 0.025 0.025 

Hexanoic Acid 76 24 0.019 1,490 66.6 1.17 

Isobutyl Alcohol 76 3 0.012 1.31 0.446 0.018 

m+p Xylene 52 2 0.013 0.352 0.183 0.183 

m-Xylene 24 2 0.153 2.13 1.14 1.14 

Methyl Methacrylate 76 0 NA NA NA NA 

n,n-Dimethylformamide 76 4 0.028 0.665 0.322 0.297 

n-Decane 75 9 0.017 1.33 0.462 0.132 

n-Docosane 76 23 0.013 141 7.97 0.164 

n-Dodecane 76 24 0.011 36.8 3.60 0.419 

n-Eicosane 76 29 0.012 14.1 1.40 0.190 

n-Hexacosane 76 19 0.011 109 7.82 0.093 

n-Hexadecane 76 28 0.015 95.3 6.64 0.444 

n-Nitrosopiperidine 76 0 NA NA NA NA 

5-5

5.0 - Wastewater Characteristics 

Table 5-2 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

n-Octacosane 76 7 0.035 61.1 11.9 0.542 

n-Octadecane 76 28 0.013 264 13.1 0.198 

n-Tetracosane 76 16 0.011 116 9.92 0.283 

n-Tetradecane 76 30 0.011 48.5 6.31 0.753 

n-Triacontane 76 12 0.012 31.9 3.89 0.666 

o+p Xylene 24 2 0.063 1.48 0.774 0.774 

o-Cresol 76 1 0.039 0.039 0.039 0.039 

o-Xylene 52 6 0.010 0.201 0.044 0.013 

p-Cresol 76 7 0.010 4.31 1.02 0.041 

p-Cymene 76 2 0.021 0.051 0.036 0.036 

Pyridine 76 0 NA NA NA NA 

Styrene 75 1 1.18 1.18 1.18 1.18 

Trichlorofluoromethane 76 1 0.106 0.106 0.106 0.106 

Tripropyleneglycol Methyl Ether 76 6 1.93 5,254 1,222 245 

Nonconventional Metal Pollutants 

Aluminum 154 132 0.039 29,600 242 2.31 

Barium 150 137 0.001 31.4 1.62 0.106 

Boron 150 127 0.022 4,150 136 1.11 

Calcium 150 145 0.274 11,600 200 39.0 

Cobalt 150 59 0.005 35.3 0.723 0.034 

Gold 3 1 1.66 1.66 1.66 1.66 

Iron 154 147 0.016 2,790 49.1 4.83 

Magnesium 150 139 0.088 213 26.1 11.6 

Manganese 154 142 0.002 20,600 146 0.190 

Molybdenum 150 100 0.003 112 2.74 0.122 

Sodium 150 147 1.61 152,000 4,908 297 

Tin 154 64 0.004 1,830 30.5 0.080 

Titanium 150 105 0.002 59.7 0.886 0.040 

Vanadium 150 64 0.002 1.07 0.095 0.023 

Yttrium 150 44 0.001 2.11 0.070 0.011 

5-6

5.0 - Wastewater Characteristics 

Table 5-2 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Other Nonconventional Pollutants 

Ammonia as Nitrogen 47 41 0.160 2,340 82.2 1.76 

Chemical Oxygen Demand (COD) 109 103 6.90 330,000 25,354 4,800 

Chloride 62 59 2 14,400 482 137 

Cyanide 9 7 0.004 0.232 0.078 0.059 

Fluoride 69 66 0.130 190 6.00 1.10 

Hexavalent Chromium 61 16 0.016 1.70 0.185 0.065 

Sulfate 86 72 1.50 46,000 1,793 121 

Total Dissolved Solids 146 146 33.5 411,420 25,197 4,200 

Total Kjeldahl Nitrogen 45 42 0.200 2,830 167 34.9 

Total Organic Carbon (TOC) 72 68 4.26 85,300 8,280 666 

Total Petroleum Hydrocarbons 

(as SGT-HEM) 69 47 6.55 6,230 489 46.0 

Total Phosphorus 39 37 0.051 7,170 276 11.0 

Total Recoverable Phenolics 109 92 0.006 33.8 1.53 0.160 

Total Sulfide 16 5 1.00 11.0 4.40 2.00 

Source: MP&M Sampling Program.
 a

Due to budgetary constraints, EPA did not analyze all samples for all pollutants.


NA - Not applicable.


5-7

5.0 - Wastewater Characteristics 

Table 5-3


Rinse Water Pollutant Concentration Data for Oily Operations


Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants 

1,1-Dichloroethane 62 1 0.039 0.039 0.039 0.039 

1,1-Dichloroethene 62 0 NA NA NA NA 

1,1,1-Trichloroethane 62 1 0.023 0.023 0.023 0.023 

2-Nitrophenol 62 0 NA NA NA NA 

2,4-Dimethylphenol 48 0 NA NA NA NA 

2,4-Dinitrophenol 59 0 NA NA NA NA 

2,6-Dinitrotoluene 62 1 0.616 0.616 0.616 0.616 

4-Chloro-3-Methylphenol 60 2 0.023 0.050 0.037 0.037 

4-Nitrophenol 60 0 NA NA NA NA 

Acenaphthene 62 0 NA NA NA NA 

Acrolein 53 0 NA NA NA NA 

Anthracene 62 0 NA NA NA NA 

Bis(2-ethylhexyl) Phthalate 62 8 0.011 1.15 0.417 0.327 

Butyl Benzyl Phthalate 62 0 NA NA NA NA 

Chlorobenzene 62 0 NA NA NA NA 

Chloroethane 62 0 NA NA NA NA 

Chloroform 62 17 0.010 0.081 0.021 0.016 

Di-n-octyl Phthalate 62 0 NA NA NA NA 

Di-n-butyl Phthalate 62 1 0.017 0.017 0.017 0.017 

Dimethyl Phthalate 62 0 NA NA NA NA 

Ethylbenzene 62 1 0.039 0.039 0.039 0.039 

Fluoranthene 62 0 NA NA NA NA 

Fluorene 62 0 NA NA NA NA 

Isophorone 62 0 NA NA NA NA 

Methylene Chloride 62 1 0.016 0.016 0.016 0.016 

n-Nitrosodiphenylamine 62 0 NA NA NA NA 

n-Nitrosodimethylamine 62 0 NA NA NA NA 

Naphthalene 62 2 0.643 2.01 1.33 1.33 

5-8

5.0 - Wastewater Characteristics 

Table 5-3 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants (continued) 

Phenanthrene 62 1 0.527 0.527 0.527 0.527 

Phenol 62 4 0.010 8.28 2.14 0.132 

Pyrene 62 0 NA NA NA NA 

Tetrachloroethene 62 0 NA NA NA NA 

Toluene 62 2 0.011 0.045 0.028 0.028 

Trichloroethene 62 9 0.011 0.022 0.017 0.018 

Metal Priority Pollutants 

Antimony 99 20 0.003 0.256 0.051 0.037 

Arsenic 100 30 0.001 0.303 0.044 0.009 

Beryllium 100 5 0.001 0.005 0.002 0.002 

Cadmium 104 30 0.002 11.9 0.432 0.012 

Chromium 104 60 0.001 104 1.97 0.082 

Copper 104 88 0.008 14.7 0.942 0.247 

Lead 104 24 0.002 6.89 0.759 0.050 

Mercury 100 14 0.0001 0.002 0.001 0.0003 

Nickel 104 50 0.001 10.3 0.434 0.099 

Selenium 99 9 0.001 0.232 0.056 0.022 

Silver 104 29 0.001 0.118 0.022 0.011 

Thallium 99 12 0.001 0.036 0.008 0.002 

Zinc 104 85 0.009 46.7 1.89 0.110 

Conventional Pollutants 

BOD 5-day (Carbonaceous) 51 42 3.04 12,900 730 47.0 

Oil and Grease (as HEM) 75 47 1.12 9,195 348 25.5 

Total Suspended Solids 102 77 5.00 2,560 201 65.0 

Nonconventional Organic Pollutants 

1-Bromo-2-Chlorobenzene 62 0 NA NA NA NA 

1-Bromo-3-Chlorobenzene 62 0 NA NA NA NA 

1-Methylfluorene 62 1 0.129 0.129 0.129 0.129 

1-Methylphenanthrene 62 1 1.02 1.02 1.02 1.02 

1,4-Dioxane 62 1 2.02 2.02 2.02 2.02 

2-Butanone 62 5 0.072 0.153 0.096 0.078 

5-9

5.0 - Wastewater Characteristics 

Table 5-3 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

2-Hexanone 62 0 NA NA NA NA 

2-Isopropylnaphthalene 62 1 1.57 1.57 1.57 1.57 

2-Methylnaphthalene 62 1 1.10 1.10 1.10 1.10 

2-Propanone 62 8 0.065 3.10 0.655 0.390 

3,6-Dimethylphenanthrene 62 1 0.811 0.811 0.811 0.811 

4-Methyl-2-Pentanone 62 0 NA NA NA NA 

Acetophenone 62 0 NA NA NA NA 

Alpha-Terpineol 52 2 65.3 67.3 66.3 66.3 

Aniline 62 0 NA NA NA NA 

Benzoic Acid 62 7 0.122 6.61 2.03 1.45 

Benzyl Alcohol 62 2 2.73 24.8 13.8 13.8 

Biphenyl 62 0 NA NA NA NA 

Carbon Disulfide 62 2 0.062 0.354 0.208 0.208 

Dibenzofuran 62 1 0.010 0.010 0.010 0.010 

Dibenzothiophene 62 0 NA NA NA NA 

Diphenyl Ether 62 0 NA NA NA NA 

Diphenylamine 62 0 NA NA NA NA 

Hexanoic Acid 62 20 0.013 28.4 1.84 0.189 

Isobutyl Alcohol 62 0 NA NA NA NA 

m-xylene 13 0 NA NA NA NA 

m+p Xylene 49 1 0.104 0.104 0.104 0.104 

Methyl Methacrylate 62 0 NA NA NA NA 

n-Eicosane 62 13 0.011 2.41 0.490 0.172 

n-Decane 62 1 5.01 5.01 5.01 5.01 

n-Docosane 62 8 0.018 6.47 0.964 0.039 

n-Dodecane 62 6 1.77 53.3 15.3 7.24 

n-Hexacosane 62 6 0.011 1.46 0.512 0.268 

n-Hexadecane 62 9 0.011 52.7 12.2 1.27 

n-Octacosane 62 3 0.396 1.37 0.818 0.684 

n-Octadecane 62 10 0.018 4.03 0.952 0.159 

n-Tetracosane 62 9 0.012 17.0 2.08 0.112 

5-10

5.0 - Wastewater Characteristics 

Table 5-3 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

n–Tetradecane 62 8 0.011 160 40.0 1.07 

n-Titrosopiperidine 62 0 NA NA NA NA 

n-Triacontane 62 2 0.039 0.322 0.180 0.180 

n,n-Dimethylformamide 62 1 0.011 0.011 0.011 0.011 

o-Cresol 62 1 0.012 0.012 0.012 0.012 

o-Xylene 49 1 0.056 0.056 0.056 0.056 

o+p Xylene 13 0 NA NA NA NA 

p-Cresol 62 3 0.014 0.063 0.030 0.014 

p-Cymene 62 1 0.190 0.190 0.190 0.190 

Pyridine 62 0 NA NA NA NA 

Styrene 62 0 NA NA NA NA 

Trichlorofluoromethane 62 1 0.036 0.036 0.036 0.036 

Tripropyleneglycol Methyl Ether 62 3 0.413 4.18 2.43 2.71 

Nonconventional Metal Pollutants 

Aluminum 104 66 0.060 321 12.9 0.389 

Barium 100 86 0.001 1.61 0.134 0.032 

Boron 100 66 0.012 838 36.6 0.223 

Calcium 100 91 0.050 175 36.1 20.8 

Cobalt 100 19 0.005 0.627 0.115 0.024 

Gold 7 3 0.056 0.086 0.074 0.081 

Iron 104 77 0.011 453 14.2 0.418 

Magnesium 100 87 0.066 37.3 9.12 6.36 

Manganese 104 79 0.001 135 4.07 0.043 

Molybdenum 100 41 0.008 187 4.71 0.045 

Sodium 100 99 1.63 19,100 524 113 

Tin 104 31 0.006 16.3 1.22 0.042 

Titanium 100 43 0.001 1.85 0.206 0.014 

Vanadium 100 23 0.001 0.182 0.026 0.014 

Yttrium 100 15 0.001 0.051 0.010 0.004 

5-11

5.0 - Wastewater Characteristics 

Table 5-3 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Other Nonconventional Pollutants 

Ammonia as Nitrogen 30 14 0.020 10.1 2.01 0.125 

Chemical Oxygen Demand (COD) 65 58 5.20 32,700 1,690 175 

Chloride 21 21 3.00 64,500 3,128 30.0 

Cyanide 2 2 0.010 1.45 0.730 0.730 

Fluoride 22 20 0.300 135 7.50 0.705 

Hexavalent Chromium 54 15 0.011 0.590 0.067 0.022 

Sulfate 48 39 2.33 780 96.0 34.8 

Total Dissolved Solids 100 99 26.0 120,000 2,955 756 

Total Kjeldahl Nitrogen 23 12 0.310 149 16.2 3.25 

Total Organic Carbon (TOC) 64 60 1.72 10,100 490 83.5 

Total Petroleum Hydrocarbons (as 

SGT-HEM) 62 29 5.00 7,367 317 27.0 

Total Phosphorus 10 9 0.060 720 85.5 7.30 

Total Recoverable Phenolics 63 43 0.005 0.800 0.110 0.050 

Total Sulfide 11 1 12.0 12.0 12.0 12.0 

Source: MP&M Sampling Program.
 a

Due to budgetary constraints, EPA did not analyze all samples for all pollutants.


NA - Not applicable.


5-12

5.0 - Wastewater Characteristics 

As shown in Tables 5-2 and Table 5-3, oil-bearing process water and rinses also 

contain numerous organic pollutants. These pollutants are either components of the oil/water 

emulsions or pollutants in the aqueous cleaning solutions. The maximum organic pollutant 

concentration found in process water samples was 5,245 mg/L for tripropyleneglycol methyl 

ether from a testing unit operation. The maximum organic pollutant concentration in the rinse 

water samples was 160 mg/L for n-tetradecane in the rinse water for a testing unit operation. 

EPA also measured the concentration of chemical oxygen demand (COD) in oil-bearing 

wastewater. The maximum COD concentration found in process water and rinse water samples 

was 330,000 mg/L and 32,700 mg/L, respectively. Data in Tables 5-2 and 5-3 show that the 

process water samples also contained conventional, nonconventional, and metal pollutants. 

In general, the organic pollutants that EPA detected most frequently were those 

associated with petroleum products used in the MP&M industry (e.g., long, straight-chain 

organic pollutants associated with oil-based machining and grinding coolants and lubricants). 

EPA also detected additional organic cleaners and solvents (e.g., phenol, 2-propanone, bis(2­

ethylhexyl) phthalate, and hexanoic acid). EPA also detected numerous metals in the oil-bearing 

waste streams. However, when compared to the metals concentrations detected in metal-bearing 

waste streams (see Appendix C), the oil-bearing waste streams contained lower median metals 

concentrations. While some specific oil-bearing wastewater streams may contain elevated 

concentrations of specific metals (e.g., machining of a copper part will generate copper-bearing 

wastewater), these streams are typically lower-flow streams as compared to other oil-bearing 

streams, resulting in lower treatment influent metals concentrations. These wastewaters may also 

contain incidental levels of metals most often in the suspended or particulate phase. 

Influent to Oily Wastewater Treatment Systems 

Wastewater containing oil and organic pollutants generated in the oily operations 

listed in Table 5-1 generally require treatment to separate oil from the wastewater. Benzene, 

toluene, ethylbenzene, and xylenes (BTEX) and other light hydrocarbons, for example, are 

moderately soluble in process waters and rinse waters. If the oils are free or floating, a 

technology such as oil skimming or ultrafiltration can separate the oil and water. If the oil is 

emulsified, techniques such as chemical emulsion breaking may be required before physical 

separation (see Section 8.4.5). Oil/water separation technologies remove organic pollutants that 

are more soluble in oil than in water from the wastewater. Table 5-4 summarizes the MP&M 

pollutant concentration data for the influent to oil/water separation, ultrafiltration, and dissolved 

air flotation treatment systems. The influent-to-treatment concentrations are typically lower than 

the concentrations of process and rinse water due to the number of high-flow, low-concentration 

rinses that are commingled prior to treatment. 

5-13


5.2 
5.0 - Wastewater Characteristics 

Table 5-4 

MP&M Pollutant Concentration Data for the Influent to 

Oily Wastewater Treatment Systems 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants 

1,1-Dichloroethane 93 1 0.011 0.011 0.011 0.011 

1,1-Dichloroethylene 93 0 NA NA NA NA 

1,1,1-Trichloroethane 93 4 0.006 0.022 0.013 0.012 

2,4-Dimethylphenol 92 2 0.017 0.270 0.144 0.144 

2,4-Dinitrophenol 79 0 NA NA NA NA 

2,6-Dinitrotoluene 93 0 NA NA NA NA 

2-Nitrophenol 93 1 0.025 0.025 0.025 0.025 

4-Chloro-m-Cresol 93 20 0.247 3,834 637 73.9 

4-Nitrophenol 85 0 NA NA NA NA 

Acenaphthene 93 5 0.006 1.82 0.396 0.025 

Acrolein 88 1 0.168 0.168 0.168 0.168 

Anthracene 93 1 0.007 0.007 0.007 0.007 

Benzyl Butyl Phthalate 92 7 0.024 2.73 0.440 0.065 

Bis(2-ethylhexyl) Phthalate 92 73 0.007 216 5.82 0.173 

Chlorobenzene 93 0 NA NA NA NA 

Chloroethane 93 0 NA NA NA NA 

Chloroform 93 6 0.010 0.038 0.019 0.016 

Di-n-butyl Phthalate 92 9 0.011 0.193 0.079 0.059 

Di-n-octyl Phthalate 93 10 0.013 19.7 2.37 0.332 

Dimethyl Phthalate 89 0 NA NA NA NA 

Ethylbenzene 94 19 0.010 14.0 0.798 0.040 

Fluoranthene 92 0 NA NA NA NA 

Fluorene 93 7 0.010 9.93 1.47 0.034 

Isophorone 89 0 NA NA NA NA 

Methylene Chloride 93 0 NA NA NA NA 

n-Nitrosodimethylamine 89 0 NA NA NA NA 

n-Nitrosodiphenylamine 93 5 0.660 2.59 1.59 1.69 

5-14

5.0 - Wastewater Characteristics 

Table 5-4 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants (continued) 

Naphthalene 93 15 0.010 8.91 1.04 0.075 

Phenanthrene 93 18 0.012 5.30 0.459 0.030 

Phenol 92 41 0.020 27.1 1.09 0.136 

Pyrene 92 2 0.031 1.01 0.521 0.521 

Tetrachloroethene 93 1 0.006 0.006 0.006 0.006 

Toluene 94 23 0.006 14.0 0.795 0.040 

Trichloroethylene 93 0 NA NA NA NA 

Metal Priority Pollutants 

Antimony 97 38 0.002 0.234 0.030 0.022 

Arsenic 97 46 0.002 0.534 0.048 0.006 

Beryllium 97 20 0.0002 0.187 0.036 0.002 

Cadmium 101 67 0.002 12.1 0.744 0.023 

Chromium 101 85 0.003 15.9 0.630 0.063 

Copper 101 101 0.027 232 19.7 0.407 

Lead 101 74 0.006 210 16.2 0.247 

Mercury 97 23 0.0001 0.003 0.001 0.0007 

Nickel 101 77 0.012 18.4 0.870 0.172 

Selenium 97 14 0.001 0.124 0.027 0.008 

Silver 101 18 0.004 2.80 0.273 0.022 

Thallium 97 6 0.001 0.068 0.012 0.001 

Zinc 101 98 0.123 664 22.7 1.66 

Conventional Pollutants 

BOD 5-Day (Carbonaceous) 82 74 4.00 34,800 3,137 641 

Oil and Grease (as HEM) 97 95 8.33 261,500 10,686 848 

Total Suspended Solids 101 99 6.00 100,000 3,251 275 

Nonconventional Organic Pollutants 

1-Bromo-2-Chlorobenzene 88 0 NA NA NA NA 

1-Bromo-3-Chlorobenzene 88 0 NA NA NA NA 

1-Methylfluorene 88 12 0.010 1.72 0.188 0.019 

1-Methylphenanthrene 88 11 0.012 1.23 0.201 0.025 

5-15

5.0 - Wastewater Characteristics 

Table 5-4 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

1,4-Dioxane 88 2 0.069 0.465 0.267 0.267 

2-Butanone 88 13 0.073 6.18 1.22 0.308 

2-Hexanone 88 2 0.505 0.512 0.509 0.509 

2-Isopropylnaphthalene 88 2 0.421 3.49 1.96 1.96 

2-Methylnaphthalene 89 21 0.011 440 21.9 0.099 

2-Propanone 88 74 0.060 28.8 3.84 0.670 

3,6-Dimethylphenanthrene 88 5 0.013 1.28 0.583 0.371 

4-Methyl-2-Pentanone 88 13 0.072 6.72 0.660 0.113 

Acetophenone 88 3 0.014 0.092 0.051 0.047 

Alpha-terpineol 88 33 0.011 189 19.4 1.43 

Aniline 88 1 0.014 0.014 0.014 0.014 

Benzoic Acid 88 4 0.098 0.522 0.315 0.320 

Benzyl Alcohol 88 7 0.011 10.8 1.63 0.141 

Biphenyl 88 10 0.014 1.54 0.226 0.060 

Carbon Disulfide 88 5 0.045 0.466 0.312 0.369 

Dibenzofuran 88 2 0.014 0.018 0.016 0.016 

Dibenzothiophene 87 3 0.015 1.29 0.452 0.048 

Diphenyl Ether 88 0 NA NA NA NA 

Diphenylamine 88 4 0.738 1.99 1.54 1.71 

Hexanoic Acid 88 34 0.011 31.9 4.27 0.561 

Isobutyl Alcohol 88 0 NA NA NA NA 

m+p Xylene 40 10 0.038 0.241 0.125 0.139 

m-Xylene 48 6 0.018 0.312 0.071 0.024 

Methyl Methacrylate 88 0 NA NA NA NA 

n,n-Dimethylformamide 88 2 0.014 0.023 0.019 0.019 

n-Decane 88 36 0.011 27.7 2.65 0.130 

n-Docosane 88 44 0.012 79.7 2.78 0.125 

n-Dodecane 88 52 0.017 207 21.0 0.594 

n-Eicosane 87 59 0.010 109 5.95 0.217 

n-Hexacosane 88 34 0.011 217 8.54 0.134 

n-Hexadecane 88 64 0.012 145 7.80 0.294 

5-16

5.0 - Wastewater Characteristics 

Table 5-4 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

n-Nitrosopiperidine 88 0 NA NA NA NA 

n-Octacosane 88 10 0.031 70.7 12.9 0.266 

n-Octadecane 88 67 0.011 162 5.66 0.214 

n-Tetracosane 87 32 0.011 56.8 3.29 0.248 

n-Tetradecane 88 64 0.011 243 15.0 0.203 

n-Triacontane 87 11 0.016 25.6 5.15 1.21 

o+p Xylene 48 6 0.011 0.030 0.021 0.021 

o-Cresol 88 0 NA NA NA NA 

o-Xylene 40 12 0.012 0.130 0.059 0.046 

p-Cresol 88 7 0.018 1.09 0.413 0.287 

p-Cymene 88 12 0.015 14.6 1.29 0.052 

Pyridine 88 15 0.014 3.42 1.02 0.063 

Styrene 88 0 NA NA NA NA 

Trichlorofluoromethane 93 0 NA NA NA NA 

Tripropyleneglycol Methyl Ether 88 14 0.447 1,680 328 4.96 

Nonconventional Metal Pollutants 

Aluminum 97 82 0.076 134 13.0 2.48 

Barium 97 96 0.006 32.0 1.89 0.217 

Boron 97 95 0.057 686 34.0 5.50 

Calcium 97 96 0.154 2,200 156 41.0 

Cobalt 97 41 0.008 1.22 0.203 0.102 

Gold 2 1 2.81 2.81 2.81 2.81 

Iron 97 95 0.604 940 47.7 10.6 

Magnesium 97 94 0.180 255 36.1 12.9 

Manganese 101 99 0.031 29.0 1.68 0.349 

Molybdenum 101 80 0.003 40.3 1.25 0.088 

Sodium 97 96 1.19 2,030 397 181 

Tin 101 58 0.003 85.2 3.05 0.053 

Titanium 97 72 0.003 1.80 0.228 0.081 

Vanadium 97 48 0.004 0.482 0.054 0.019 

Yttrium 97 23 0.001 1.00 0.094 0.011 

5-17

5.0 - Wastewater Characteristics 

Table 5-4 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Other Nonconventional Pollutants 

Amenable Cyanide 4 0 NA NA NA NA 

Ammonia as Nitrogen 15 15 0.021 160 32.7 0.500 

Chemical Oxygen Demand (COD) 96 96 30.0 213,000 23,722 5,660 

Chloride 11 11 22.0 450 83.1 27.0 

Cyanide 4 2 0.006 0.007 0.007 0.007 

Fluoride 16 16 0.500 17.0 2.54 1.00 

Hexavalent Chromium 78 12 0.011 1.74 0.212 0.020 

Sulfate 39 38 16.0 176,000 13,957 405 

Total Dissolved Solids 93 93 70.0 88,800 9,341 2,450 

Total Kjeldahl Nitrogen 15 15 0.840 1,500 222 3.10 

Total Organic Carbon (TOC) 81 79 7.66 106,000 6,181 1,340 

Total Petroleum Hydrocarbons (as 

SGT-HEM) 81 75 5.07 25,431 1,941 507 

Total Phosphorus 24 24 0.160 240 38.9 25.6 

Total Recoverable Phenolics 95 91 0.005 1,360 58.6 0.240 

Total Sulfide 27 24 2.00 18.0 7.13 5.50 

Source: MP&M Sampling Program.
 a

Due to budgetary constraints, EPA did not analyze all samples for all pollutants.


NA - Not applicable.


5-18

6.0 - Industry Subcategorization 

6.0 INDUSTRY SUBCATEGORIZATION 

This section discusses the subcategorization evaluated for the final rule (MP&M 

Point Source Category). Section 6.1 discusses the methodology and factors considered when 

determining the subcategories evaluated for the final rule. Section 6.2 describes the types of 

facilities included in each subcategory evaluated for the final rule. 

As discussed below, EPA proposed effluent limitations and standards for eight 

subcategories. However, for reasons discussed in Section 9.0 and Section VI of the preamble to 

the final rule, the final rule only establishes effluent limitations guidelines and standards for new 

and existing direct dischargers in one subcategory: Oily Wastes (40 CFR 438, Subpart A). 

6.1 Methodology and Factors Considered for Basis of Subcategorization 

In order to address variations between products, raw materials processed, and 

other factors that result in distinctly different effluent characteristics, EPA proposed eight 

groupings called “subcategories” for the January 2001 proposal and June 2002 Notice of Data 

Availability (NODA). EPA retained this subcategory structure for evaluating options for the 

final rule. Regulation of a category using subcategories allows each subcategory to have a 

uniform set of effluent limitations that take into account technological achievability and 

economic impacts unique to that subcategory. The Clean Water Act (CWA) requires EPA, in 

developing effluent limitations guidelines and pretreatment standards, to consider a number of 

different subcategorization factors. The statute also authorizes EPA to take into account other 

factors the Agency deems appropriate. 

eight subcategories for the final rule: 

� Unit operation; 

� Activity; 

� Raw materials; 

� Products; 

� Size of site; 

EPA considered the following factors in evaluating the 

� Geographic location;


� Facility age;


� Nature of the waste generated;


� Economic impacts;


� Treatment costs;


� Total energy requirements;


� Air pollution control methods; and


� Solid waste generation and disposal.


As a result of this evaluation, EPA retained the eight subcategories for evaluating 

options for the final rule as shown in Table 6-1. 

6-1

6.0 - Industry Subcategorization 

Table 6-1


Final Subcategories Evaluated in the Final Rule


Facilities that Generate Metal-Bearing Wastewater 

(With or Without Oil-Bearing Wastewater) 

Facilities that Generate Only Oil-Bearing 

Wastewater 

General Metalsa 

Metal Finishing Job Shopsa 

Non-Chromium Anodizinga 

Printed Wiring Boarda 

Steel Forming and Finishinga 

Oily Wastes 

Railroad Line Maintenancea 

Shipbuilding Dry Docka 

a

For reasons discussed in Section 9.0 and Section VI of the preamble to the final rule, EPA did not establish effluent 

guidelines for these subcategories. 

6.1.1	 Factors Contributing to the Subcategorization Structure Evaluated for the 

Final Rule 

As discussed in Section 5.0 and Appendix C, facilities performing proposed 

MP&M operations1 generate two basic types of waste streams: (1) wastewater with relatively 

high metals content (metal-bearing, including hexavalent chromium-bearing and cyanidebearing), and (2) wastewater with relatively low metals content and/or relatively high oil and 

grease content (oil-bearing). The type of wastewater a facility generates is directly related to the 

unit operations it performs. For example, unit operations such as machining, grinding, aqueous 

degreasing, and impact or pressure deformation tend to generate a wastewater with relatively 

high oil and grease (and associated organic pollutants) loadings but relatively low concentrations 

of metal pollutants. Other unit operations such as electroplating, conversion coating, chemical 

etching and milling, and anodizing generate higher metals loadings with moderate or low oil and 

grease concentrations or generate wastewater containing both metals and oil and grease. EPA 

defined “oily operations” in the final rule (see 40 CFR 438.2(f) and Appendix B to Part 438) and 

these final MP&M operations are listed in Table 6-2. EPA defined “metal-bearing operations” in 

the final rule (see 40 CFR 438.2(d) and Appendix C to Part 438) and these proposed MP&M 

operations are listed in Table 6-3. 

1

EPA evaluated a number of unit operations for the May 1995 proposal, January 2001 proposal, and June 2002 

NODA (see Tables 6-2 and 6-3). However, EPA selected a subset of these unit operations for regulation in the final 

rule (see Section 1.0). For this section, the term “proposed MP&M operations” means those operations evaluated for 

the two proposals, NODA, and final rule. The term “final MP&M operations” means those operations defined as 

“oily operations” (see Section 1.0, 40 CFR 438.2(f), and Appendix B to Part 438) and regulated by the final rule. 

6-2 
6.0 - Industry Subcategorization 

Table 6-2


Oily Operations as Defined by the Final Rule


� Abrasive Blasting � Iron Phosphate Conversion Coating


� Adhesive Bonding � Machining


� Alkaline Cleaning for Oil Removal � Painting-spray or Brush (Including Water Curtains)


� Alkaline Treatment Without Cyanide � Polishing


� Aqueous Degreasing � Pressure Deformation 


� Assembly/Disassembly � Solvent Degreasing


� Burnishing � Steam Cleaning


� Calibration � Testing (e.g., Hydrostatic, Dye Penetrant, Ultrasonic, Magnetic


� Corrosion Preventive Coating 

Flux)


� Electrical Discharge Machining � Thermal Cutting


� Floor Cleaning (In Process Area) � Tumbling/Barrel Finishing/Mass Finishing/Vibratory Finishing 


� Grinding � Washing (Finished Products)


� Heat Treating � Welding


� Impact Deformation � Wet Air Pollution Control for Organic Constituents


Note: This list is replicated at 40 CFR 438.2(f) with definitions at Appendix B to Part 438. 

6-3

6.0 - Industry Subcategorization 

Table 6-3


Metal-Bearing Operations as Defined by the Final Rule


� Abrasive Jet Machining � Mechanical and Vapor Plating 

� Acid Pickling Neutralization � Metallic Fiber Cloth Manufacturing 

� Acid Treatment With Chromium � Metal Spraying (including Water Curtain) 

� Acid Treatment Without Chromium � Painting-immersion (including Electrophoretic, 

� Alcohol Cleaning "E-coat") 

� Alkaline Cleaning Neutralization � Photo Imaging 

� Alkaline Treatment With Cyanide � Photo Image Developing 

� Anodizing With Chromium � Photoresist Application 

� Anodizing Without Chromium � Photoresist Strip 

� Carbon Black Deposition � Phosphor Deposition 

� Catalyst Acid Pre-dip � Physical Vapor Deposition 

� Chemical Conversion Coating Without Chromium � Plasma Arc Machining 

� Chemical Milling (or Chemical Machining) � Plastic Wire Extrusion 

� Chromate Conversion Coating (or Chromating) � Salt Bath Descaling 

� Chromium Drag-out Destruction � Shot Tower - Lead Shot Manufacturing 

� Cyanide Drag-out Destruction � Soldering 

� Cyaniding Rinse � Solder Flux Cleaning 

� Electrochemical Machining � Solder Fusing 

� Electroless Catalyst Solution � Solder Masking 

� Electroless Plating � Sputtering 

� Electrolytic Cleaning � Stripping (Paint) 

� Electroplating With Chromium � Stripping (Metallic Coating) 

� Electroplating With Cyanide � Thermal Infusion 

� Electroplating Without Chromium or Cyanide � Ultrasonic Machining 

� Electropolishing � Vacuum Impregnation 

� Galvanizing/Hot Dip Coating � Vacuum Plating 

� Hot Dip Coating � Water Shedder 

� Kerfing � Wet Air Pollution Control 

� Laminating � Wire Galvanizing Flux 

Note: This list is replicated at 40 CFR 438.2(d) with definitions at Appendix C to Part 438. 

6-4

6.0 - Industry Subcategorization 

Although many facilities performing proposed MP&M operations generate both 

metal- and oil-bearing wastewater, a large number of facilities, typically machine shops and 

maintenance and repair facilities, only generate process wastewater from oily operations (see 

Table 6-2). Because the wastewater at these facilities primarily contains oil and grease and other 

organic constituents, these facilities use treatment technologies that focus on oil removal only 

and do not include the chemical precipitation step needed to treat metal-bearing wastewater. 

These treatment technologies generally include oil skimming, chemical emulsion breaking 

followed by either gravity flotation, coalescing plate oil/water separators, dissolved air flotation 

(DAF), or ultrafiltration. Therefore, EPA first divided facilities on the basis of unit operations 

performed and the nature of the wastewater generated, resulting in the following two wastewater 

groups: (1) metal-bearing (with or without oily and organic constituents) group; and (2) oilbearing only group. EPA then identified any significant differences in the subcategorization 

factors within the two basic groups. 

Metal-Bearing Wastewater (With or Without Oil-Bearing Wastewater) 

When evaluating facilities generating metal-bearing wastewater (with or without 

oil-bearing wastewater) for the final rule, EPA identified five groups of facilities that could 

potentially be subcategorized by dominant product, raw materials used, and/or nature of the 

waste generated: steel forming and finishing facilities, non-chromium anodizing facilities, metal 

finishing job shops, printed wiring board facilities, and general metals facilities. In two of these 

groups (non-chromium anodizing and metal finishing job shops), EPA also considered economic 

impacts as a subcategorization factor because of the reduced ability of these facilities to afford 

treatment costs. EPA describes its rationale for subcategorizing each of these groups below (see 

Section 6.2 for additional detailed discussion and applicability). In general, EPA identified four 

distinct groups within the metal-bearing group that warranted splitting out from the rest of this 

group. 

Steel Forming and Finishing Facilities 

EPA proposed moving certain finishing operations subject to the Iron and Steel 

Manufacturing effluent guidelines (40 CFR 420) into the scope of the MP&M regulations 

because EPA’s analyses, at that time, showed these operations to be more similar to MP&M 

operations than to iron and steel operations (see W-00-25, Section 14.1, DCN IS10883). In the 

MP&M proposed rule, these operations (at stand-alone facilities and at steel manufacturing 

facilities) would have been subject to the limits and standards in the proposed Steel Forming and 

Finishing Subcategory. This subcategory would have applied to wastewater discharges from 

finishing or cold forming operations on steel wire, rod, bar, pipe, or tube. In order to better assess 

potential economic impacts associated with the final rule, EPA concluded that facilities 

performing these operations should be evaluated as a separate subcategory when EPA selected 

options for the final rule. 

Commentors on the proposed rule stated that these operations and resulting 

wastewaters are comparable to those at facilities subject to the Iron and Steel Manufacturing 

6-5

6.0 - Industry Subcategorization 

effluent guidelines and that these discharges should remain subject to Part 420 rather than the 

final MP&M rule. In addition, commentors stated that Part 420 adequately protects the 

environment from discharges associated with these activities. 

For reasons discussed in Section 9.0, EPA is not revising limitations or standards 

for any facilities that would have been subject to this subcategory. Such facilities will continue to 

be regulated by the General Pretreatment Standards (Part 403), local limits, permit limits, and 

Iron and Steel effluent limitations guidelines (Part 420) as applicable. 

Non-Chromium Anodizing Facilities 

The non-chromium anodizers differ from other metal-bearing facilities performing 

proposed MP&M operations in that all of their products are primarily of one metal type, anodized 

aluminum, and, most importantly, they do not use chromic acid, dichromate sealants, or other 

process solutions containing significant concentrations of chromium in their anodizing process. 

Table 6-4 shows the percentage of facilities using multiple metal types by subcategory. EPA’s 

data show that these facilities have very low levels of metals (with the exception of aluminum) 

and toxic organic pollutants in their wastewater discharges, while other facilities performing 

proposed MP&M operations have much greater concentrations of a wider variety of metals. 

Table 6-4 

Percentage of Facilities Performing Proposed MP&M Operations Using 

Multiple Metal Types by Subcategory 

Subcategory 

Percentage of Facilities by Number of Metal Types Processed 

1 2 3 4 5-10 >10 

General Metals 31 32 13 8 15 1 

Metal Finishing Job Shops 6 18 17 13 38 7 

Non-Chromium Anodizing 100 0 0 0 0 0 

Oily Wastes 46 17 32 3 2 0 

Printed Wiring Board 4 1 20 17 56 2 

Railroad Line Maintenance 76 8 16 0 0 0 

Shipbuilding Dry Dock 57 0 29 14 0 0 

Steel Forming and Finishing 56 25 14 3 3 0 

Source: MP&M Survey Database. 

In addition, non-chromium anodizing facilities require more extensive wastewater 

treatment systems than other metal-bearing facilities performing proposed MP&M operations to 

remove both very high concentrations of aluminum (and resulting large volumes of wastewater 

treatment sludge) and relatively low levels of alloy metals generated in their wastewater. As a 

6-6

6.0 - Industry Subcategorization 

result, these facilities have relatively higher treatment costs compared to other metal-bearing 

facilities. EPA also found that, due to their current economic state, non-chromium anodizing 

facilities are less able to afford pollutant control technologies as compared to other types of 

facilities (see the Economic, Environmental, and Benefits Analysis for the Final Metal Products 

& Machinery Rule (EEBA) (EPA-821-B-03-002)). Therefore, based on the differences in raw 

materials used, nature of the waste generated, treatment costs, and economic conditions, EPA 

concluded that non-chromium anodizing facilities should be evaluated as a separate subcategory 

when EPA selected options for the final rule. 

For reasons discussed in Section 9.0, EPA is not revising limitations or standards 

for any facilities that would have been subject to this subcategory. Such facilities will continue 

to be regulated by the General Pretreatment Standards (Part 403), local limits, permit limits, and 

Parts 413 and/or 433, as applicable. 

Metal Finishing Job Shops 

EPA investigated whether to subcategorize the metal finishing and electroplating 

job shops covered currently by the Metal Finishing (40 CFR 433) and Electroplating (40 CFR 

413) effluent guidelines (with the exception of printed circuit board manufacturers, which were 

analyzed as a separate subcategory as discussed below). Although these facilities have metal 

types that require the same treatment technologies as many other metal-bearing facilities, EPA 

determined that they can be different due to the variability of their raw materials and products as 

well as their current economic state compared to other metal-bearing facilities performing 

proposed MP&M operations. Metal finishing and electroplating job shops perform electroplating, 

electroless plating, anodizing, coating, and chemical etching and milling, and are “job shops” as 

defined in the Metal Finishing effluent guidelines (i.e., as owning less than 50 percent of the 

products processed on site). 

Because metal finishing job shops work on a contract basis, they cannot always 

predict the type of plating or other finishing operations required. In addition, because these 

facilities work on a large variety of metal types from various customers, their wastewater 

characteristics can vary from week to week (or even day to day). Table 6-5 demonstrates the 

variety of metal types processed at metal finishing job shops as compared to the rest of the 

industry. EPA performed sampling to specifically identify the variability in the wastewater 

generated at metal finishing job shops, and found that the variability factors calculated solely on 

the analytical wastewater sampling data from metal finishing and electroplating job shops are 

higher for most pollutant parameters than those calculated for other metal-bearing subcategories 

(see Section 10.1 for a discussion of EPA’s variability factor calculations). In addition, EPA 

found that, due to the current economic state, metal finishing job shops are less able to afford 

pollutant control technologies compared to other metal-bearing subcategories (see the EEBA). 

For these reasons, EPA concluded that metal finishing and electroplating job shops should be 

evaluated as a separate subcategory when EPA selected options for the final rule. 

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6.0 - Industry Subcategorization 

Table 6-5 

Percentage of Facilities Performing Proposed MP&M Operations by 

Subcategory Using Each Metal Type 

Metal 

Percentage of Facilities by Subcategory 

General 

Metals 

Metal 

Finishing 

Job Shops 

NonChromium 

Anodizing 

Oily 

Wastes 

Printed 

Wiring 

Board 

Railroad 

Line 

Maintenance 

Shipbuilding 

Dry Dock 

Steel 

Forming 

and 

Finishing 

Aluminum 69 154 88 67 17 32 14 3 

Beryllium < 1 0 0 0 0 0 0 0 

Cadmium 2 12 0 0 0 0 0 3 

Chromium 9 21 0 < 1 4 0 0 10 

Cobalt 4 0 0 1 2 0 0 3 

Copper 29 50 0 20 99 8 43 10 

Gold 4 13 0 < 1 73 0 0 0 

Indium < 1 0 0 < 1 0 0 0 0 

Iron 82 94 12 96 5 100 100 100 

Lead 6 4 0 1 72 0 0 1 

Magnesium 3 6 0 1 0 0 0 0 

Manganese < 1 0 0 < 1 1 0 0 0 

Molybdenum 1 0 0 0 5 0 0 0 

Nickel 17 54 0 5 79 0 43 5 

Palladium 1 0 0 1 5 0 0 0 

Platinum 1 1 0 0 0 0 0 0 

Rhodium 1 7 0 0 3 0 0 0 

Selenium < 1 0 0 0 0 0 0 0 

Silver 3 17 0 < 1 10 0 0 0 

Tantalum 1 0 0 < 1 0 0 0 0 

Tin 15 29 0 2 89 0 0 5 

Titanium 3 3 0 2 0 0 0 3 

Tungsten 1 0 0 < 1 0 0 0 0 

Vanadium 0 0 0 < 1 0 0 0 0 

Zinc 18 59 0 3 4 0 0 29 

Zirconium < 1 0 0 < 1 0 0 0 0 

Source: MP&M Survey Database. 

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6.0 - Industry Subcategorization 

For reasons discussed in Section 9.0, EPA is not revising any limitations or 

standards for facilities that would have been subject to this subcategory. Such facilities will 

continue to be regulated by the General Pretreatment Standards (Part 403), local limits, permit 

limits, and Parts 413 and/or 433, as applicable. 

Printed Wiring Board Facilities 

EPA subcategorized printed wiring board facilities based on raw materials, unit 

operations performed, primary product, and nature of the waste generated. First, as shown in 

Table 6-5, printed wiring board facilities process a more consistent set of metal types (copper, 

tin, lead, nickel, and gold) than other metal-bearing facilities. EPA concluded that this consistent 

mix of metal types enables printed wiring board facilities to tailor their treatment technology. 

Printed wiring board facilities generally work with copper-clad laminate material, allowing them 

to target copper for removal in their wastewater treatment systems or recover the copper using inprocess ion exchange. 

Second, printed wiring board facilities apply, develop, and strip photoresist - a set 

of unit operations that is unique to this subcategory. This process produces a higher 

concentration of a more consistent group of organic constituents than other facilities in the metalbearing group. Printed wiring board facilities also require chelation breaking more often than 

other facilities performing proposed MP&M operations. Finally, the nature of the wastewater 

generated at these facilities may also be different because these facilities perform more leadbearing operations (e.g., lead/tin electroplating, wave soldering) than other facilities performing 

proposed MP&M operations. For these reasons, EPA concluded that printed wiring board 

facilities should be evaluated as a separate subcategory when EPA selected options for the final 

rule. 

At proposal, EPA included printed wiring board job shops in the Metal Finishing 

Job Shops Subcategory based on the similar economic considerations for job shops. However, 

information submitted by commentors in response to the proposed rule indicates that printed 

wiring board job shops are much more similar to Printed Wiring Board Subcategory facilities 

than to metal finishing job shops when considering their wastewater characteristics and 

operations. Therefore, for the final rule, EPA included printed wiring board job shops in the 

Printed Wiring Board Subcategory evaluated for the final rule. 

For reasons discussed in Section 9.0, EPA is not revising any limitations or 

standards for facilities that would have been subject to this subcategory. Such facilities will 

continue to be regulated by the General Pretreatment Standards (Part 403), local limits, permit 

limits, and Parts 413 and/or 433, as applicable. 

General Metals Facilities 

After developing separate subcategories for non-chromium anodizing facilities, 

metal finishing job shops, printed wiring board facilities, and steel forming and finishing 

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6.0 - Industry Subcategorization 

facilities, EPA grouped the remaining metal-bearing wastewater generating facilities performing 

proposed MP&M operations into a subcategory entitled “General Metals” for evaluating options 

for the final rule. This subcategory would be a “catch-all” for metal-bearing wastewatergenerating facilities that do not fall into any of the previous subcategories. For example, 

wastewater generated from most manufacturing operations and heavy rebuilding operations (e.g., 

aircraft, aerospace, auto, bus/truck, railroad) would be grouped under the General Metals 

Subcategory. 

Based on comments received on the proposed rule, EPA reviewed the unit 

operations of printed wiring assembly facilities and determined that they are most similar to the 

facilities in the General Metals Subcategory (discussed below). Printed wiring assembly 

facilities do not manufacture printed circuit boards, but instead attach circuit boards to other 

structures. Therefore, they do not perform the operations typical of a printed wiring board 

facility (e.g., applying photoresist, etching the board, or stripping). At proposal, EPA included 

most printed wiring assembly facilities in the General Metals Subcategory; however, some were 

included in the Printed Wiring Board Subcategory. For the final rule, EPA included all printed 

wiring assembly facilities in the General Metals Subcategory. 

As discussed in the NODA (67 FR 38767), EPA considered establishing a 

segment of the Steel Forming and Finishing Subcategory for discharges resulting from 

continuous electroplating of flat steel products (e.g., strip, sheet, and plate). EPA reexamined its 

database for facilities that perform continuous steel electroplating, and found that, contrary to its 

initial finding, continuous electroplaters do not perform operations similar to other facilities in 

this subcategory (i.e., steel forming and finishing facilities performing cold forming on steel 

wire, rod, bar, pipe, and tube) (see Section 24.6.1 of the rulemaking record, DCN 17919). Thus, 

EPA included continuous electroplaters performing electroplating and coating operations in the 

General Metals Subcategory for evaluating options for the final rule. 

As also discussed in the NODA, EPA also considered an additional subcategory 

for facilities that primarily perform zinc electroplating (“zinc platers”). EPA uses the term ‘‘zinc 

platers’’ to describe facilities where over 95 percent of their wastewater is generated from zinc 

electroplating lines. Most of these facilities follow electroplating with chromium conversion 

coating. Depending on whether or not these facilities operate as a captive or a job shop, EPA had 

proposed to include them as part of the General Metals or Metal Finishing Job Shops 

Subcategories, respectively. The wastewater characteristics of zinc platers differ from other 

facilities in these two subcategories, particularly with respect to their concentrations of zinc. 

Where nonzinc platers may have concentrations of 10 to 90 mg/l zinc in their wastewater prior to 

treatment, zinc platers have concentrations of 100 to 800 mg/l zinc in their wastewater prior to 

treatment. However, zinc platers have very low concentrations of other pollutants as compared 

to nonzinc platers. 

The NODA explained that EPA was also considering: (1) creating a separate 

subcategory for zinc platers; (2) segmenting zinc platers within the General Metals and Metal 

Finishing Job Shops Subcategories; or (3) retaining the proposed subcategory structure and 

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6.0 - Industry Subcategorization 

establishing numerical limitations and standards for zinc that would be achievable by zinc 

platers. NODA commentors supported retaining the proposed subcategories as long as zinc 

platers could achieve the zinc numerical limitations and standards. Commentors raised concerns 

that creating a separate subcategory or segment to address the limitations for one pollutant would 

be confusing and difficult to implement. EPA did not create a separate subcategory or segment 

for zinc platers in evaluating the data for the final rule. EPA included zinc platers in the General 

Metals or Metal Finishing Job Shops Subcategories, as applicable, for evaluating options for the 

final rule. 

For reasons discussed in Section 9.0, EPA is not revising or establishing any 

limitations or standards for facilities that would have been subject to this subcategory. Such 

facilities will continue to be regulated by the General Pretreatment Standards (Part 403), local 

limits, permit limits, and Parts 413 and/or 433, as applicable. 

In summary, EPA divided facilities that generate metal-bearing wastewater, with 

or without oil-bearing wastewater, into the following five subcategories: (1) non-chromium 

anodizing facilities; (2) metal finishing job shops; (3) printed wiring board facilities; (4) steel 

forming and finishing; and (5) general metals facilities. 

Oil-Bearing Wastewater Only Group 

When evaluating facilities generating oil-bearing wastewater for the final rule, 

EPA identified three groups of facilities that could potentially be subcategorized by size, 

location, and dominant product or activity: railroad line maintenance facilities, shipbuilding dry 

docks or similar structures, and oily wastes facilities (see Section 6.2 for detailed descriptions of 

these subcategories). 

Railroad line maintenance facilities perform routine cleaning and light 

maintenance on railroad engines, cars, car-wheel trucks, or similar parts or machines, and 

discharge wastewater exclusively from oily operations (see Section 1.0). EPA subcategorized 

railroad line maintenance facilities due to their outdoor location, unit operations performed, and 

low level of pollutant loadings they discharge to the environment. EPA also determined that the 

railroad line maintenance facilities discharge a much more limited range of organic pollutants 

than general oily-wastewater-bearing facilities. These facilities perform only one or more of the 

following operations: assembly/disassembly, floor cleaning, maintenance machining (wheel 

truing), touch-up painting, and washing. In addition, because some of these operations are 

typically performed outdoors, stormwater collection and treatment is of concern for this 

subcategory. Therefore, EPA included railroad line maintenance facilities in the Railroad Line 

Maintenance Subcategory evaluated for the final rule. EPA notes that this subcategory does not 

include railroad manufacturing facilities or railroad overhaul or heavy maintenance facilities. 

The second type of facility is dry docks (and similar structures such as graving 

docks, building ways, lift barges, and marine railways). These are large, outdoor areas, exposed 

to precipitation, where shipyards perform final assembly, maintenance, rebuilding, and repair 

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6.0 - Industry Subcategorization 

work on large ships and boats. In evaluating options for the final rule, EPA grouped shipbuilding 

dry docks and similar structures in the Shipbuilding Dry Dock Subcategory due to their size, 

outdoor location, low level of pollutant loadings they discharge to the environment, and the fact 

this wastewater is unique to the shipbuilding industry. This subcategory does not include other 

proposed MP&M operations that occur at shipyards (e.g., shore-side operations such as 

electroplating). 

The facilities that generate only oil-bearing wastewater but are not dry docks or 

railroad line maintenance facilities fall into the Oily Wastes Subcategory (40 CFR 438, Subpart 

A). These facilities meet the applicability criteria in Section 438.1 and discharge only oil-bearing 

wastewater and perform one or more oily operations listed in Table 6-2. 

EPA received comments at proposal concerning the definition of ‘‘oily 

operations’’ used in the applicability statement of the Oily Wastes Subcategory (see Section 

6.2.5). Commentors provided data on several proposed MP&M operations that were not 

considered ‘‘oily operations’’ in the proposed rule. These operations include: 

� Abrasive blasting;


� Adhesive bonding;


� Alkaline treatment without cyanide; 


� Assembly/disassembly;


� Burnishing;


� Calibration;


� Electrical discharge machining;


� Iron phosphate conversion coating;


� Painting-spray or brush (including water curtains);


� Polishing; 


� Thermal cutting;


� Tumbling/barrel finishing/mass finishing/vibratory finishing;


� Washing (finished products);


� Welding; and


� Wet air pollution control for organic constituents.


The data show low levels of metals in these unit operations. Based on the data received and a 

review of other unit operations containing only low metals content, EPA revised the definition of 

‘‘oily operations’’ in the Oily Wastes Subcategory (see 40 CFR 438.2(f)) to incorporate these 

additional unit operations considered in the NODA, with the exception of bilge water. Bilge 

water from ships that are afloat is not considered an in-scope wastewater for any subcategories of 

the MP&M rule and was inadvertently included in the oily operations definition in the NODA. 

Bilge water from ships in a dry dock or similar structure is considered for the Shipbuilding Dry 

Dock Subcategory only. 

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6.0 - Industry Subcategorization 

In addition, EPA is no longer including wastewater from laundering as part of the 

oily operations definition because EPA does not consider it to be a process wastewater under this 

rule (67 FR 38766). 

For reasons discussed in Section 9.0, EPA is only promulgating limitations and 

standards for existing and new direct dischargers in the Oily Wastes Subcategory. EPA is not 

promulgating pretreatment standards for existing or new indirect dischargers in this subcategory. 

In summary, EPA divided facilities that generate only oil-bearing wastewater into 

the following three subcategories: (1) railroad line maintenance facilities; (2) shipbuilding dry 

docks (and similar structures); and (3) oily wastes facilities. 

For reasons discussed in Section 9.0, EPA is not establishing limitations or 

standards for any facilities in two subcategories evaluated for the final rule that only discharge 

oil-bearing wastewater: Railroad Line Maintenance Subcategory and Shipbuilding Dry Dock 

Subcategory. Permit writers and control authorities will establish controls using best professional 

judgment (BPJ) to regulate wastewater discharges from these facilities. 

6.1.2 Factors That are Not a Basis For MP&M Subcategorization 

During its consideration of the final rule, EPA examined the other factors listed 

earlier in this section for possible basis of subcategorization. The Agency determined that there 

was no basis for subcategorizing facilities performing proposed MP&M operations based on the 

following factors: geographic location, age of facilities, total energy requirements, air pollution 

control methods, and solid waste generation and disposal. These factors are discussed below. In 

addition, EPA also considered subcategorizing the facilities performing proposed MP&M 

operations according to the 18 industrial sectors proposed in the January 2001 proposal (66 FR 

424). As described in Section 1.0, EPA did not regulate the following industrial sectors (Job 

Shops, Printed Wiring Board Manufacturing, and Steel Forming & Finishing) as part of the final 

rule. As discussed in Section 6.1.1, and further discussed below, EPA determined for evaluating 

options for the final rule that subcategorization based on sectors was appropriate for only one 

sector (printed wiring boards), and for portions of three other sectors (railroad, ships and boats, 

and job shops). 

For the Steel Forming and Finishing Subcategory, EPA did not have sector 

information from the Iron and Steel Surveys; therefore, EPA evaluated the steel forming and 

finishing sites as their own subcategory for the proposed and final rule. EPA concluded that the 

basis for subcategorization is the difference in the raw material and primary product at these 

facilities. Facilities in this proposed subcategory primarily process steel and, for the most part, 

produce uniformly shaped products such as wire, rod, bar, pipe, and tube. In addition, this is the 

only subcategory for which EPA proposed to cover forming operations under the MP&M 

regulations. 

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6.0 - Industry Subcategorization 

Geographic Location 

Facilities performing proposed MP&M operations are located throughout the 

United States. Sites are not limited to any one geographical location, but approximately half are 

located east of the Mississippi River, with additional concentrations of facilities in Texas, 

Colorado, and California. EPA did not subcategorize based on geographic location because 

location does not affect the ability of facilities to comply with the MP&M final rule. EPA’s data 

show that well-performing facilities are located throughout the United States. 

Geographic location may impact costs if additional land is required to install 

treatment systems, because the cost of the land will vary depending on whether the site is located 

in an urban or rural location. However, the treatment systems used to treat wastewater typically 

do not have large land requirements, as demonstrated by the fact that many facilities performing 

proposed MP&M operations are located in urban settings. The Agency, however, recognizes that 

spatial constraints may present a problem for certain facilities and believes this issue should be 

evaluated on a case-by-case basis. 

Water availability is another function of geographical location. Limited water 

supply encourages efficient use of water. The Agency encourages installing water recycle and 

reuse practices. Some technology options evaluated for the final rule include pollution 

prevention and water conservation because these practices tend to reduce treatment costs and 

improve pollutant removals. 

Facility Age 

Figure 6-1 presents the percentage of water-discharging facilities by the decade in 

which they were built. This information is based upon responses to MP&M surveys that reported 

the date the facility was built. 

Most facilities have been built since 1970. Although the survey respondents 

reported a wide range of ages, these facilities must be continually modernized to remain 

competitive. Most of the facilities EPA visited during the MP&M site visit program had recently 

modernized some area of their site. Modernizing production processes and air pollution control 

equipment results in generation of similar process waste types regardless of the site’s age. 

Therefore, EPA did not select facility age as a basis for subcategorization. EPA’s data show that 

well-performing facilities include both older and newer facilities. 

Total Energy Requirements 

EPA did not select total energy requirements as a basis for subcategorization 

because the estimated increase in energy consumption for the final rule is trivial (< 0.001 

percent) as compared to national energy usage (see Section 13.0). EPA estimated the energy 

requirements associated with each MP&M technology option and considered these in estimating 

compliance costs (see Section 11.0). 

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6.0 - Industry Subcategorization 

Before 1920 

2% 

1920s 

1% 

1930s 

4% 

1940s 

2% 

1950s 

4% 1960s 

7% 

1980s 

1990s 

15% 

1970s 

17% 

48% 

Source: MP&M Survey Database. 

Note:	 Although there are 44,000 wastewater-discharging facilities performing 

proposed MP&M operations, only 42,282 are represented in the above pie 

chart. Several 1989 and 1996 Long Survey and several Municipality Survey 

recipients did not provide this information. 

Figure 6-1. Percentage of Wastewater-Discharging Facilities Evaluated 

for the Final Rule by Decade Built 

Air Pollution Control Methods 

Many facilities control air emissions using wet air pollution control units that 

affect the wastewater flow rate from the site. However, based on data collected during the 

MP&M sampling program, wastewater generated by these devices does not affect the 

effectiveness of technologies used to control wastewater pollutant loadings from proposed 

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6.0 - Industry Subcategorization 

MP&M operations (see Sections 5.2 and 15.3 of the rulemaking record). EPA considers some 

wet air pollution control units as proposed MP&M operations, but not as a basis of 

subcategorizing the category. 

Industrial Sectors 

EPA considered subcategorizing facilities performing proposed MP&M 

operations by industrial sector (e.g., aerospace, aircraft, bus and truck, electronic equipment, 

hardware, household equipment, instruments, job shops, mobile industrial equipment, motor 

vehicles, office machines, ordnance, precious metals and jewelry, printed wiring boards, railroad, 

ships and boats, stationary industrial equipment, steel forming and finishing, and miscellaneous 

metal products). The Agency determined that subcategorization based solely on industrial sector 

would be complex and confusing because many facilities are in multiple sectors. Adopting such 

a subcategorization scheme would complicate the implementation of the limitations and 

standards because permit writers might be required to develop facility-specific limitations across 

multiple subcategories. 

The Agency determined that wastewater characteristics, unit operations, and raw 

materials used to produce products within a given sector are not always the same from site to 

site, and they are not always different from sector to sector. Within each sector, facilities can 

perform a variety of unit operations on a variety of raw materials. For example, a site in the 

aerospace sector may primarily machine aluminum missile components and not perform any 

surface treatment other than alkaline cleaning. Another site in that sector may electroplate iron 

parts for missiles and perform little or no machining. Wastewater characteristics from these 

facilities may differ because of the different unit operations performed and different raw 

materials used. As another example, an automobile manufacturer and an automobile repair 

facility are both part of the motor vehicle sector. However, the automobile manufacturer may 

perform unit operations that generate metal-bearing and oil-bearing wastewater (aqueous 

degreasing, electroplating, chemical conversion coating, etc.) while the automobile repair facility 

may perform unit operations that generate only oil-bearing wastewater (machining, aqueous 

degreasing, impact deformation, painting, etc.). 

Based on the analytical data collected for this rule, EPA has not found a 

statistically significant difference in industrial wastewater discharge among industrial sectors 

when performing similar unit operations for cadmium, chromium, copper, cyanide, lead, 

manganese, molybdenum, nickel, oil and grease, silver, tin, total suspended solids (TSS), and 

zinc. (The analytical data are available in Sections 5 and 15 of the rulemaking record.) In other 

words, after dividing facilities performing proposed MP&M operations according to the unit 

operations performed (metal-bearing or oil-bearing operations), EPA concluded that raw 

wastewater has similar treatability across all of the industrial sectors. For example, a facility that 

performs chromium electroplating in the process of manufacturing office machines produces 

metal-bearing wastewater with similar chemical characteristics as a facility that performs 

chromium electroplating in the process of manufacturing a part for a bus. Similarly, a facility 

that performs machining to repair and maintain an airplane engine produces oil-bearing 

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6.0 - Industry Subcategorization 

wastewater that has similar chemical characteristics to a facility that performs machining to 

repair and maintain construction machinery. 

Most proposed MP&M operations are not unique to a particular sector and are 

performed across all sectors. For example, all sectors perform several of the major wastewatergenerating unit operations (e.g., alkaline treatment, acid treatment, machining, electroplating). 

And, for the most part, the unit operations that are rarely performed (e.g., abrasive jet machining) 

are not performed in all sectors, but are also not limited to a single sector. Therefore, a facility in 

any one of the proposed industrial sectors can generate metal-bearing or oil-bearing wastewater 

(or a combination of both) depending on what unit operations the facility performs. 

Due to the reasons stated above, EPA determined that a regulation based on 

industrial sector would create a variety of implementation issues for state and local regulators as 

well as for those multiple-sector facilities. As a result, EPA did not use industrial sector as a 

basis for subcategorizing the industry. 

Solid Waste Generation and Disposal 

Physical and chemical characteristics of solid waste generated by facilities 

performing proposed MP&M operations are determined by the raw materials, unit operations, 

and types of air pollution control in use. Therefore, this factor does not provide a primary basis 

for subcategorization. The subcategorization scheme that EPA is promulgating should account 

for any variations in solid waste generation and disposal. EPA considered the amount of sludge 

generated as a result of the MP&M technology options, and included disposal of these sludges in 

the compliance cost estimates (see Section 11.0) and non-water quality impact assessments (see 

Section 13.0). 

General Description of Facilities in Each Subcategory Evaluated for the 

Final Rule 

Below is a general description of the types of facilities that fall within each of the 

subcategories evaluated for the final rule. Sections 11.0 and 12.0 present information on 

compliance costs and pollutant reductions, respectively, evaluated for the final rule for each 

proposed subcategory. However, for reasons discussed in Section 9.0 and Section VI of the 

preamble to the final rule, the final rule establishes effluent limitations guidelines and standards 

for new and existing direct dischargers in one subcategory: Oily Wastes (40 CFR 438, Subpart 

A). 

6.2.1 General Metals Subcategory Evaluated for the Final Rule 

As discussed in Section 6.1, the General Metals Subcategory evaluated for the 

final rule is a “catch-all” for facilities performing proposed MP&M operations that discharge 

metal-bearing wastewater (with or without oil-bearing wastewater) that do not fit the 

applicability of the Metal Finishing Job Shops, Non-Chromium Anodizing, and Printed Wiring 

6-17


6.2 
6.0 - Industry Subcategorization 

Board Subcategories evaluated for the final rule. This proposed subcategory also includes 

general metals facilities that are owned and operated by the federal government, states and 

municipalities. General metals facilities typically perform manufacturing or heavy rebuilding of 

metal products, parts, or machines. Facilities that perform metal finishing or electroplating 

operations on site, but do not meet the definition of a job shop (i.e., captive shops), would fit in 

the proposed General Metals Subcategory. EPA also includes continuous electroplaters of flat 

steel products (e.g., strip, sheet, and plate) in the General Metals Subcategory evaluated for the 

final rule. 

Wastewater discharges from railroad overhaul or heavy maintenance facilities 

may be covered by the MP&M effluent guidelines (Subpart A), the Metal Finishing Point Source 

Category (40 CFR 433), or by other effluent limitations guidelines, as applicable. This provision 

is codified at 40 CFR 438.1(d). Facilities engaged in the manufacture, overhaul or heavy 

maintenance of railroad engines, cars, car-wheel trucks, or similar parts or machines (“railroad 

overhaul or heavy maintenance facilities”) typically perform different unit operations than 

railroad line maintenance facilities. Railroad line maintenance facilities perform routine cleaning 

and light maintenance on railroad engines, cars, car-wheel trucks, or similar parts or machines, 

and discharge wastewater exclusively from oily operations. These facilities only perform one or 

more of the following operations: assembly/disassembly, floor cleaning, maintenance machining 

(wheel truing), touch-up painting, and washing. 

Railroad overhaul or heavy maintenance facilities are engaged in the manufacture, 

overhaul, or heavy maintenance of railroad engines, cars, car-wheel trucks, or similar parts or 

machines. These facilities typically perform one or more of the same operations as railroad line 

maintenance facilities and one or more of the following operations: abrasive blasting, alkaline 

cleaning, aqueous degreasing, corrosion preventive coating, electrical discharge machining, 

grinding, heat treating, impact deformation, painting, plasma arc machining, polishing, pressure 

deformation, soldering/brazing, stripping (paint), testing, thermal cutting, and welding. 

Depending on the operations performed, railroad overhaul or heavy maintenance facilities may 

be included in the proposed General Metals Subcategory or the Oily Wastes Subcategory. 

EPA estimates that there are approximately 10,914 indirect dischargers and 250 

direct dischargers in the General Metals Subcategory evaluated for the final rule. EPA currently 

regulates 99 percent of the facilities in this proposed subcategory by existing effluent guidelines. 

Some general metals facilities are currently covered by multiple regulations. The Agency 

estimates that, based on responses to its questionnaires, the Metal Finishing (40 CFR 433) and 

Electroplating (40 CFR 413) effluent guidelines cover approximately 89 percent and 16 percent, 

respectively, of general metals facilities. Approximately 50 percent of the general metals 

facilities are covered by other metal-related effluent guidelines (see Section 1.2.7). Facilities in 

the proposed General Metals Subcategory are specifically not regulated by the final rule (see 40 

CFR 438.1(b)). 

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6.0 - Industry Subcategorization 

6.2.2 Metal Finishing Job Shops Subcategory Evaluated for the Final Rule 

Facilities in the Metal Finishing Job Shops Subcategory evaluated for the final 

rule met the following criteria: (1) perform one or more of the following five operations: 

electroplating, electroless plating, anodizing, chemical conversion coating (chromating, 

phosphating, passivation, and coloring), and chemical etching and milling, and (2) own not more 

than 50 percent (on an annual area basis) of the materials undergoing metal finishing. (Note that 

printed wiring board job shops are in the Printed Wiring Board Subcategory evaluated for the 

final rule based on the operations performed and wastewater characteristics.) 

The Agency estimates that there are approximately 1,530 indirect dischargers and 

12 direct dischargers in the Metal Finishing Job Shops Subcategory evaluated for the final rule. 

EPA currently regulates all facilities in this proposed subcategory under the existing Metal 

Finishing or Electroplating effluent guidelines and standards. 

EPA has identified approximately 32,139 facilities that meet the definition of job 

shop but do not perform one or more of the five metal finishing operations listed above. EPA 

does not consider such job shops to be part of the Metal Finishing Job Shops Subcategory. These 

other job shops typically perform assembly, painting, and machining on a contract basis and are 

included in the General Metals, Oily Wastes, or Printed Wiring Board Subcategories evaluated 

for the final rule. Facilities in the Metal Finishing Job Shops proposed subcategory are 

specifically not regulated by the final rule (see 40 CFR 438.1(b)). 

6.2.3 Non-Chromium Anodizing Subcategory Evaluated for the Final Rule 

Facilities in the Non-Chromium Anodizing Subcategory evaluated for the final 

rule performed aluminum anodizing without using chromic acid or dichromate sealants. 

Anodizing is a surface conversion operation used to alter the properties of aluminum for better 

corrosion resistance and heat transfer. Generally, non-chromium anodizing facilities perform 

sulfuric acid anodizing; however, facilities can use other acids (except chromic acid), such as 

oxalic acid, for aluminum anodizing. In evaluating options for the final rule, EPA included 

anodizers that use chromic acid or dichromate in the proposed General Metals Subcategory or, if 

they operate as a job shop, in the proposed Metal Finishing Job Shops Subcategory. 

Some facilities that could potentially fall into the proposed Non-Chromium 

Anodizing Subcategory also may perform other metal surface finishing operations. If these 

facilities commingle wastewater from their non-chromium anodizing operations with wastewater 

from other surface finishing operations (e.g., chromic acid anodizing, electroplating, chemical 

conversion coating) for treatment, or perform chromium-bearing operations on site, they would 

not be included in the proposed Non-Chromium Anodizing Subcategory. Instead, the proposed 

General Metals or Metal Finishing Job Shops Subcategories would apply. 

EPA estimates that there are approximately 122 indirect dischargers in the 

proposed Non-Chromium Anodizing Subcategory. EPA did not identify any direct discharging 

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6.0 - Industry Subcategorization 

non-chromium anodizers in its survey efforts. The wastewater generated at non-chromium 

anodizing facilities contains relatively low levels of metals, with the exception of aluminum, and 

low levels of toxic organic pollutants. Facilities in the proposed Non-Chromium Anodizing 

Subcategory are specifically not regulated by the final rule (see 40 CFR 438.1(b)). 

6.2.4 Printed Wiring Board Subcategory Evaluated for the Final Rule 

The Printed Wiring Board Subcategory evaluated for the final rule includes 

wastewater discharges from the manufacture and repair of printed wiring boards (i.e., circuit 

boards), including job shops. However, printed wiring assembly facilities are included in the 

General Metals Subcategory evaluated for the final rule. EPA currently regulates all facilities in 

this proposed subcategory by the existing Metal Finishing or Electroplating effluent limitation 

guidelines and standards. EPA estimates that there are approximately 840 indirect dischargers 

and 8 direct dischargers in the Printed Wiring Board Subcategory evaluated for the final rule. 

Facilities in the Printed Wiring Board Subcategory evaluated for the final rule are specifically not 

regulated by the final rule (see 40 CFR 438.1(b)). 

6.2.5 Steel Forming and Finishing Subcategory Evaluated for the Final Rule 

Facilities in the Steel Forming and Finishing Subcategory evaluated for the final 

rule performed MP&M finishing operations and/or cold forming operations on steel wire, rod, 

bar, pipe, or tube. This subcategory does not include facilities that perform those operations on 

other base materials. Generally, steel forming and finishing facilities perform acid pickling, 

annealing, conversion coating (e.g., zinc phosphate, copper sulfate), hot dip coating and/or 

electroplating of steel wire or rod, heat treatment, welding, drawing, patenting, and oil tempering. 

EPA estimates that there are approximately 110 indirect and 43 direct dischargers 

in the proposed Steel Forming and Finishing Subcategory. EPA currently regulates all facilities 

in this proposed subcategory under the Iron and Steel Point Source Category (40 CFR 420). 

Facilities in the proposed Steel Forming and Finishing Subcategory are specifically not regulated 

by the final rule (see 40 CFR 438.1(b)). 

6.2.6 Oily Wastes Subcategory 

The Oily Wastes Subcategory established in the final rule is a “catch-all” for 

facilities in one or more of the 16 industrial sectors (see Section 1.0) performing proposed “oily 

operations” (see Table 6-2) and are not specifically excluded by the applicability to the final rule 

(see Section 1.0 and 40 CFR 438.1). EPA defined the applicability of this subcategory by the 

presence of specific unit operations (see Table 6-2). Facilities in the proposed Railroad Line 

Maintenance or Shipbuilding Dry Dock Subcategories (see below) are not subject to the Oily 

Wastes Subcategory in the final rule (see Section 1.0 and 40 CFR 438.1(d) and 438.1(e)(5)). 

Facilities in the Oily Wastes Subcategory are predominantly machine shops or maintenance and 

repair shops. This subcategory also includes federal, municipal, and state-owned facilities 

performing only the listed operations. 

6-20

6.0 - Industry Subcategorization 

In the final rule, EPA also clarified the applicability of certain unit operations. 

EPA defined “corrosion preventive coating” in the final rule (40 CFR 438.2(c)) as “the 

application of removable oily or organic solutions to protect metal surfaces against corrosive 

environments. Corrosion preventive coatings include, but are not limited to: petrolatum 

compounds, oils, hard dry-film compounds, solvent-cutback petroleum-based compounds, 

emulsions, water-displacing polar compounds, and fingerprint removers and neutralizers. 

Corrosion preventive coating does not include electroplating, or chemical conversion coating 

operations.” EPA’s analytical database shows that wastewater generated from phosphate 

conversion coating operations may contain high levels of zinc, nickel, and manganese (see 

Section 16.5.1 of the rulemaking record, DCN 16715). 

However, based on comments on the January 2001 proposal and June 2002 

NODA, EPA added iron phosphate conversion coating to the final list of oily operations (see 40 

CFR 438.2(f) and Appendix B to Part 438). EPA defined iron phosphate conversion coating as 

“the process of applying a protective coating on the surface of a metal using a bath consisting of 

a phosphoric acid solution containing no metals (e.g., manganese, nickel, or zinc) or a phosphate 

salt solution (i.e., sodium or potassium salts of phosphoric acid solutions) containing no metals 

(e.g., manganese, nickel, or zinc) other than sodium or potassium. Any metal concentrations in 

the bath are from the substrate.” EPA notes that iron phosphate conversion coating should be 

distinguished from zinc, manganese, or nickel phosphate conversion coating based on the 

constituents of the bath. Manganese, nickel, or zinc phosphate conversion coating baths contain 

metals in addition to what may be added from the substrate. 

If a facility discharges wastewater from any of the operations listed in Table 6-2, 

but also discharges wastewater from any of the operations listed in Table 6-3, it does not meet 

the criteria of the Oily Wastes Subcategory but instead would have been included under either the 

proposed General Metals Subcategory or another metal-bearing wastewater proposed 

subcategory. EPA determined that both of the following wastewaters require some form of 

wastewater treatment (e.g., chemical precipitation) to properly remove metals: (1) wastewaters 

from metal-bearing operations; and (2) wastewaters commingled from metal-bearing operations 

and oily operations. Thus, the final regulations do not apply to the discharge of wastewater from 

oily operations commingled with wastewater from metal-bearing operations. Additionally, the 

regulations in the final rule do not apply to process wastewater discharges subject to the 

limitations and standards of other effluent limitations guidelines (e.g., Metal Finishing (40 CFR 

433) or Iron and Steel Manufacturing (40 CFR 420)). These provisions are codified in the final 

rule at 40 CFR 438.1(b): 

“The regulations in this part do not apply to process wastewaters from metalbearing operations (as defined at §438.2(d) and Appendix C of this part) or 

process wastewaters which are subject to the limitations and standards of other 

effluent limitations guidelines (e.g., Metal Finishing (40 CFR 433) or Iron and 

Steel Manufacturing (40 CFR 420)). The regulations in this part also do not apply 

to process wastewaters from oily operations (as defined at §438.2(f) and 

Appendix B of this part) commingled with process wastewaters already covered 

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6.0 - Industry Subcategorization 

by other effluent limitations guidelines or with process wastewaters from 

metal-bearing operations. This provision must be examined for each point source 

discharge at a given facility.” 

Wastewater discharges from railroad overhaul or heavy maintenance facilities 

may be covered by the MP&M effluent guidelines (Subpart A), the Metal Finishing Point Source 

Category (40 CFR 433), or by other effluent limitations guidelines, as applicable. This provision 

is codified at 40 CFR 438.1(d). Facilities engaged in the manufacture, overhaul or heavy 

maintenance of railroad engines, cars, car-wheel trucks, or similar parts or machines (“railroad 

overhaul or heavy maintenance facilities”) typically perform different unit operations than 

railroad line maintenance facilities. Railroad line maintenance facilities perform routine cleaning 

and light maintenance on railroad engines, cars, car-wheel trucks, or similar parts or machines, 

and discharge wastewater exclusively from oily operations. These facilities only perform one or 

more of the following operations: assembly/disassembly, floor cleaning, maintenance machining 

(wheel truing), touch-up painting, and washing. 

Railroad overhaul or heavy maintenance facilities are engaged in the manufacture, 

overhaul, or heavy maintenance of railroad engines, cars, car-wheel trucks, or similar parts or 

machines. These facilities typically perform one or more of the same operations as railroad line 

maintenance facilities and one or more of the following operations: abrasive blasting, alkaline 

cleaning, aqueous degreasing, corrosion preventive coating, electrical discharge machining, 

grinding, heat treating, impact deformation, painting, plasma arc machining, polishing, pressure 

deformation, soldering/brazing, stripping (paint), testing, thermal cutting, and welding. 

Depending on the operations performed, railroad overhaul or heavy maintenance facilities may 

be included in the proposed General Metals Subcategory or the Oily Wastes Subcategory. 

EPA estimates that there are approximately 26,824 indirect dischargers and 2,382 

direct dischargers in the Oily Wastes Subcategory. EPA has concluded that less than two percent 

of the MP&M process wastewater discharged from the facilities in this subcategory is covered by 

existing effluent guidelines. Limitations and standards for this subcategory are given in Section 

1.0 and at 40 CFR 438, Subpart A (Oily Wastes). 

6.2.7 Railroad Line Maintenance Subcategory Evaluated for the Final Rule 

The Railroad Line Maintenance Subcategory evaluated for the final rule included 

facilities that perform routine cleaning and light maintenance (mostly consisting of parts 

replacement) on railroad engines, cars, car-wheel trucks, and similar parts or machines. These 

facilities discharge wastewater from only those proposed MP&M operations that EPA defines as 

oily operations (see Table 6-2). The wastewater generated at railroad line maintenance facilities 

contains relatively low levels of metals and toxic organic pollutants. Because these operations 

are conducted outdoors, these facilities may also discharge large volumes of stormwater that may 

or may not be commingled with process wastewater. 

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6.0 - Industry Subcategorization 

Railroad line maintenance facilities are similar to facilities in the Oily Wastes 

Subcategory in that they produce oil-bearing wastewater and do not perform MP&M operations 

that generate wastewater that requires metals removal treatment technology. This proposed 

subcategory does not include railroad manufacturing facilities or railroad overhaul or heavy 

maintenance facilities. Railroad manufacturing facilities and railroad overhaul or heavy 

maintenance facilities perform operations more similar to operations in the proposed General 

Metals Subcategory (e.g., acid treatment without chromium) and Oily Wastes Subcategory (e.g., 

heat treating and impact deformation). 

EPA estimates that there are approximately 820 indirect dischargers and 9 direct 

dischargers in the proposed Railroad Line Maintenance Subcategory evaluated for the final rule. 

Facilities in the proposed Railroad Line Maintenance Subcategory are specifically not regulated 

by the final rule (see Section 1.0 and 40 CFR 438.1(d)). Additionally, EPA did not establish and 

limitations and standards for the proposed General Metals Subcategory (see Section 9.0). 

Consequently, railroad manufacturing facilities and railroad overhaul or heavy maintenance 

facilities in the proposed General Metals Subcategory will continue to be regulated by the 

General Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, 

as applicable. 

6.2.8 Shipbuilding Dry Dock Subcategory 

The Shipbuilding Dry Dock Subcategory evaluated for the final rule included 

wastewater generated in or on dry docks and similar structures such as graving docks, building 

ways, marine railways, and lift barges at shipbuilding facilities (or shipyards). Shipbuilding 

facilities use these structures to maintain, repair, or rebuild existing ships, or perform the final 

assembly and launching of new ships (including barges). Shipbuilders use these structures to 

reach surfaces and parts that would otherwise be under water. Because dry docks and similar 

structures include sumps or containment systems, shipyards can control the discharge of 

pollutants to surface water. Typical proposed MP&M operations that occur in dry docks and 

similar structures include: abrasive blasting; hydro-blasting; painting; welding; corrosion 

preventive coating; floor cleaning; aqueous degreasing; and testing. Not all of these proposed 

MP&M operations generate wastewater. The proposed subcategory also included wastewater 

generated when a shipyard cleans a ship’s hull in a dry dock (or similar structure) to remove 

marine life (e.g., barnacles) in preparation for performing proposed MP&M operations. 

This subcategory included only process wastewater generated and discharged 

from proposed MP&M operations inside and outside ships (including bilge water) that occur in 

or on dry docks or similar structures. The Agency is not including process wastewater from 

proposed MP&M operations that is generated at other locations at the shipyard (“on-shore” 

operations) in this proposed subcategory. EPA included these wastewaters from these “onshore” shipbuilding operations (e.g., electroplating, plasma arc cutting) in the proposed General 

Metals Subcategory or Oily Wastes Subcategory. Also, EPA is not including wastewater 

generated onboard ships when they are afloat (i.e., not in dry docks or similar structures). For 

U.S. military ships, EPA is in the process of establishing standards under the Uniform National 

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6.0 - Industry Subcategorization 

Discharge Standards (UNDS) pursuant to Section 312(n) of the CWA (see 64 FR 25125; May 

10, 1999) to regulate discharges of wastewater generated onboard these ships when they are in 

U.S. waters and are afloat (e.g., at a shipyard’s dock). 

In addition to wastewater from proposed MP&M operations, three other types of 

water streams are in or on dry docks and similar structures: flooding water, dry dock ballast 

water, and stormwater. Flooding water enters and exits the dry dock or similar structure prior to 

performing any MP&M operations. For example, in a graving dock, the gates are opened, 

allowing flooding water in and ships to float inside the chamber. Then the flooding water is 

drained, leaving the ship’s exterior exposed so shipyard employees can repair and maintain the 

ship’s hull. Dry dock ballast water serves a similar purpose. It is used to lower (or sink) a 

floating dry dock so that a ship can float over it. Then the dry dock ballast water is pumped out, 

raising the dry dock with the ship on top. Flooding water and dry dock ballast water are not 

directly associated with proposed MP&M operations. Finally, because these structures are 

located outdoors and are exposed to the elements, stormwater may fall in or on the dry dock or 

similar structures. 

In its evaluation, EPA excluded all three of these water streams (i.e., flooding 

water, dry dock ballast water, and stormwater) from the proposed definition of process 

wastewater specific to the Shipbuilding Dry Dock Subcategory. Stormwater at these facilities is 

covered by EPA’s Storm Water Multi-Sector General Permit, similar general permits issued by 

authorized states, and individual stormwater permits. In general, stormwater permits at shipyards 

include best management practices (BMPs) that are designed to prevent the contamination of 

stormwater. For example, these practices include sweeping areas after paint stripping or painting 

are completed. 

Many shipyards perform only dry proposed MP&M operations in their dry docks 

(and similar structures) or do not discharge wastewater generated in dry docks (and similar 

structures) from proposed MP&M operations. Many shipyards prefer to handle this wastewater 

as hazardous, and contract haul it off site due to the possible presence of copper or tin (used as an 

antifoulant) in paint chips from paint stripping operations. The wastewater discharged from dry 

docks and similar structures contains relatively low levels of metals and toxic organic pollutants. 

EPA estimates that there are nine indirect dischargers and six direct dischargers in 

the Shipbuilding Dry Dock Subcategory evaluated for the final rule. Many shipbuilders operate 

multiple dry docks (or similar structures); this is the number of estimated facilities (not dry 

docks) that discharge process wastewater from proposed MP&M operations at dry docks or 

similar structures. Facilities in the proposed Shipbuilding Dry Dock Subcategory are specifically 

not regulated by the final rule (see Section 1.0 and 40 CFR 438.1(e)(5)). 

6-24

7.0 - Selection of Pollutant Parameters 

7.0 SELECTION OF POLLUTANT PARAMETERS 

This section discusses the criteria EPA used to identify pollutants of concern 

(POCs) and regulated pollutants. For the final rule, EPA evaluated process wastewater from 

proposed MP&M operations1 to determine the presence of priority, conventional, and 

nonconventional pollutant parameters. EPA reviewed data on 308 metal and organic pollutant 

parameters listed in The 1990 Industrial Technology Division List of Analytes (1) under the 

MP&M final rule. These pollutants are listed in Section 3.0, Tables 3-5 and 3-6. The Agency 

also evaluated regulating 24 conventional and other nonconventional pollutant bulk parameters 

under the MP&M rule. These pollutants are listed in Section 3.0, Table 3-7. 

Section 7.1 discusses the criteria EPA used to identify POCs for the MP&M final 

rule. POCs are pollutants EPA has identified at significant concentrations in process wastewater 

from proposed MP&M operations. While EPA generally considers the full list of POCs in its 

analysis, it regulates only a subset of these pollutants. Section 7.2 presents the criteria EPA used 

to select the regulated pollutants. Section 7.3 presents the references used in this section. 

7.1 Identification of Pollutants of Concern 

EPA performed the POC analysis using the analytical data from the Phase I and 

Phase II sampling programs. The POC analysis identifies those pollutants present in industry 

wastewater at significant concentrations. These pollutants are evaluated in the pollutant 

reduction analysis (Section 11.0) and further considered for regulation. To identify POCs for the 

MP&M rulemaking, EPA analyzed for 329 pollutants in over 1,994 samples of unit operation 

processes and rinse water, wastewater treatment influent, and wastewater treatment effluent 

during the Phase I and Phase II sampling programs. EPA did not use data collected during the 

post-proposal sampling program and industry-supplied data in the POC analysis. The Agency 

excluded acidity, total alkalinity, and pH from the POC analysis since these pollutant parameters 

do not have a detection limit. 

EPA performed the POC analysis using all data across proposed subcategories 

evaluated for the final rule. When determining regulated pollutants (Section 7.2), EPA 

considered proposed subcategory-specific factors. EPA identified POCs primarily using data 

from proposed MP&M operations (both process baths and rinses) and wastewater treatment 

influent data. The pollutants generated depend more on the nature of the unit operations than the 

subcategory in which the operation is performed (e.g., pollutants present in a machinery 

operation conducted on steel parts will be similar across subcategories). While the oil-bearing 

subcategories exclude operations generating high concentrations of metal pollutants, EPA still 

1

Note: EPA evaluated a number of unit operations for the May 1995 proposal, January 2001 proposal, and June 2002 

NODA (see Tables 4-3 and 4-4). However, EPA selected a subset of these unit operations for regulation in the final 

rule (see Section 1.0). For this section, the term “proposed MP&M operations” means those operations evaluated for 

the two proposals, NODA, and final rule. The term “final MP&M operations” means those operations defined as 

“oily operations” (see Section 1.0, 40 CFR 438.2(f), and Appendix B to Part 438) and regulated by the final rule. 

7-1 
7.0 - Selection of Pollutant Parameters 

detected many metal pollutants in oil-bearing wastewaters (see Section 5.0) and therefore 

considered these to be POCs. 

EPA reduced the list of 329 analyzed pollutants to 132 POCs by retaining only 

those pollutants that met the following criteria: 

� EPA detected the pollutant in at least three samples collected during the 

MP&M sampling programs. For this evaluation, EPA considered all 

samples collected from Phase I and Phase II process water, rinse water, 

wastewater treatment influent, or wastewater treatment effluent. 

� The average of all the detected concentrations of the pollutant in samples 

of wastewater from proposed MP&M operations and treatment system 

influents was at least five times the minimum level (ML). EPA describes 

the ML as “the lowest level at which the entire analytical system must give 

a recognizable signal and an acceptable calibration point for the 

analyte” (2). EPA evaluated the unit operation, rinse, and treatment 

influent data to identify those pollutants present in raw wastewater. EPA 

did not evaluate the effluent data for this step because the treatment 

systems are designed to remove pollutants, so including effluent data in 

this step may have artificially lowered the average concentration. 

� EPA analyzed the pollutant in a quantitative manner following the 

appropriate quality assurance/quality control (QA/QC) procedures. Thus, 

wastewater analyses performed solely for certain semiquantitative 

“screening” purposes did not meet this criterion, and EPA excluded these 

results from the POCs analysis. EPA performed these semiquantitative 

analyses only in unusual cases (e.g., to qualitatively screen for the presence 

of a rare metal such as osmium). 

For the first criterion, EPA combined data from the unit operation, treatment 

system influent, and treatment system effluent wastewater samples to determine the total number 

of samples in which each pollutant was detected. 

EPA calculated the average detected pollutant concentrations of the unit operation 

wastewater and treatment system influent samples to determine if the data met the second 

criterion. In this analysis, EPA focused only on detected pollutants so nondetected pollutants 

were not included. For pollutants not meeting the second criterion based on this calculation (i.e., 

the average detected pollutant concentration in samples of unit operation wastewater and 

treatment system influent samples was less than five times the ML), EPA also calculated the 

average detected pollutant concentration in the treatment system effluent and determined whether 

those averages exceeded five times the ML. EPA took this step for two reasons. First, the 

Agency wanted to identify any pollutants that were generated during treatment. For example, 

EPA determined that chloroform can be produced in alkaline chlorination systems and adjusted 

7-2

7.0 - Selection of Pollutant Parameters 

the pollutant removal model accordingly. Second, matrix interferences associated with unit 

operation and wastewater treatment influent samples may have masked the presence of a 

pollutant in a unit operation or influent sample. For six pollutants (1,1-dichloroethene, 

chloroform, diphenyl ether, isophorone, n-nitrosopiperidine, and trichlorofluoromethane), the 

average treatment system effluent concentrations exceeded five times the ML. Consequently, 

EPA considered these compounds POCs. 

As explained above, EPA started with a possible list of 329 pollutants. The 

Agency excluded acidity, total alkalinity, and pH from the POC analysis since these pollutant 

parameters do not have a detection limit. EPA also excluded oil and grease (EPA Method 413.2) 

from the POC analysis since oil and grease (as HEM) was included. Therefore, these pollutant 

parameters were not considered for regulation under the final MP&M rule. 

Of the 324 remaining pollutants EPA initially considered regulating under 

MP&M, EPA excluded 192 as POCs because they failed to meet the following criteria: 

� EPA did not detect 113 pollutant parameters in samples collected during 

the Phase I and Phase II MP&M sampling programs. Table 7-1 lists these 

pollutants. 

� EPA detected 50 pollutants in less than three samples collected during the 

Phase I and Phase II MP&M sampling programs. Table 7-2 lists these 

pollutants. 

� EPA detected 23 pollutants at average detected concentrations that were 

less than five times the ML in unit operation wastewater and treatment 

system influent. Table 7-3 lists these pollutants. 

� EPA performed analyses for 42 pollutants, listed in Section 3.0, Table 3-5, 

using semiquantitative methods for “screening” purposes to determine if 

these analytes were present. For this screening, the Agency did not use the 

QA/QC procedures required by analytical method 1620. EPA excluded 

the six pollutants (strontium, potassium, platinum, sulfur, silicon, and 

phosphorus) that passed the first three criteria but were part of the 

screening analysis. Based on the screening results, EPA did not measure 

for these pollutants in a quantitative manner. 

After excluding these pollutants, EPA defined the 132 remaining pollutants as 

POCs for further evaluation with respect to technology options and the performance of the 

technologies. These include 47 priority pollutants (34 priority organic pollutants, 13 priority 

metal pollutants), 3 conventional pollutants, and 82 nonconventional pollutants (50 organic 

pollutants, 15 metal pollutants, and 17 other nonconventional pollutants). Table 7-4 lists these 

pollutants, along with the number of times EPA analyzed for and detected each pollutant 

7-3

7.0 - Selection of Pollutant Parameters 

Table 7-1 

Pollutants Not Detected in Any Samples Collected During the Phase I and 

Phase II MP&M Sampling Programs 

Priority Pollutants 

1,2-Dichloropropane Benzo(K)Fluoranthene 

1,3-Dichlorobenzene Bis(2-Chloroisopropyl) Ether 

2-Chloroethylvinyl Ether Chrysene 

3,3'-Dichlorobenzidine Dibenzo(A,H)Anthracene 

4-Bromophenyl Phenyl Ether Hexachlorobenzene 

4-Chlorophenylphenyl Ether Hexachlorobutadiene 

Acenaphthylene Hexachlorocyclopentadiene 

Benzidine Hexachloroethane 

Benzo(A)Anthracene Indeno(1,2,3-Cd)Pyrene 

Benzo(A)Pyrene Pentachlorophenol 

Benzo(B)Fluoranthene Trans-1,2-Dichloroethene 

Benzo(Ghi)Perylene Trans-1,3-Dichloropropene 

Nonconventional Organic Pollutants 

1,2,3-Trichlorobenzene 2-Nitroaniline 

1,2,3-Trichloropropane 2-Phenylnaphthalene 

1,2,3-Trimethoxybenzene 2-Propen-1-Ol 

1,2,4,5-Tetrachlorobenzene 2-Propenenitrile, 2-Methyl1,2-Dibromo-3-Chloropropane 3,3'-Dimethoxybenzidine 

1,2-Dibromoethane 3,5-Dibromo 4-Hydroxybenzonitrile 

1,3-Butadiene, 2-Chloro 3-Chloropropene 

1,3-Dichloro-2-Propanol 3-Methylcholanthrene 

1,3-Dichloropropane 3-Nitroaniline 

1,5-Naphthalenediamine 4,4'-Methylenebis(2-Chloroaniline) 

1-Chloro-3-Nitrobenzene 4,5-Methylene Phenanthrene 

1-Phenylnaphthalene 4-Chloro-2-Nitroaniline 

2,3,4,6-Tetrachlorophenol 5-Nitro-O-Toluidine 

2,3,6-Trichlorophenol 7,12-Dimethylbenz(A)Anthracene 

2,3-Benzofluorene Aniline, 2,4,5-Trimethyl2,3-Dichloroaniline Aramite 

2,3-Dichloronitrobenzene Benzanthrone 

2,4,5-Trichlorophenol Benzenethiol 

2,6-Dichloro-4-Nitroaniline Biphenyl, 4-Nitro 

2,6-Dichlorophenol Chloroacetonitrile 

2-Methylbenzothioazole Crotonaldehyde 

Crotoxyphos Methyl Methanesulfonate 

7-4

7.0 - Selection of Pollutant Parameters 

Table 7-1 (Continued) 

Nonconventional Organic Pollutants (continued) 

Diethyl Ether n-Nitrosodiethylamine 

Dimethyl Sulfone o-Toluidine, 5-ChloroDiphenyldisulfide p-Dimethylaminoazobenzene 

Ethyl Cyanide Pentachlorobenzene 

Ethyl Methacrylate Pentachloroethane 

Ethyl Methanesulfonate Perylene 

Hexachloropropene Phenacetin 

Iodomethane Pronamide 

Isosafrole Squalene 

Longifolene Thioacetamide 

Malachite Green Trans-1,4-Dichloro-2-Butene 

Mestranol Triphenylene 

Methapyrilene Vinyl Acetate 

Nonconventional Metal Pollutants 

Cerium Praseodymium 

Erbium Rhenium 

Europium Samarium 

Gadolinium Scandium 

Gallium Tellurium 

Germanium Terbium 

Holmium Thorium 

Indium Thulium 

Iodine Uranium 

Lanthanum 

Source: MP&M Sampling Data. 

7-5

7.0 - Selection of Pollutant Parameters 

Table 7-2 

Pollutants Detected in Less Than Three Samples Collected 

During the Phase I and Phase II MP&M Sampling Programs 

Priority Pollutants 

1,1,2,2-Tetrachloroethane 2-Chloronaphthalene 

1,1,2-Trichloroethane 2-Chlorophenol 

1,2,4-Trichlorobenzene Acrylonitrile 

1,2-Dichlorobenzene Bis(2-Chloroethoxy) Methane 

1,2-Dichloroethane Bis(2-Chloroethyl) Ether 

1,2-Diphenylhydrazine Bromomethane 

1,4-Dichlorobenzene Nitrobenzene 

2,4-Dichlorophenol n-Nitrosodi-n-Propylamine 

2,4-Dinitrotoluene Vinyl Chloride 

Nonconventional Organic Pollutants 

1,1,1,2-Tetrachloroethane Ethylenethiourea 

1,2:3,4-Diepoxybutane n-Nitrosodi-n-Butylamine 

1,3,5-Trithiane n-Nitrosomethylphenylamine 

1,4-Dinitrobenzene o-Anisidine 

1,4-Naphthoquinone p-Chloroaniline 

1-Naphthylamine Pentamethylbenzene 

2,6-Di-Tert-Butyl-P-Benzoquinone Phenothiazine 

2-Picoline p-Nitroaniline 

4-Aminobiphenyl Resorcinol 

Beta-Naphthylamine Safrole 

Carbazole Thianaphthene 

Cis-1,3-Dichloropropene Thioxanthe-9-One 

Dibromomethane Toluene, 2,4-DiaminoNonconventional Metal Pollutants 

Dysprosium Rhodium 

Hafnium Ruthenium 

Neodymium Zirconium 

Source: MP&M Sampling Data. 

7-6

7.0 - Selection of Pollutant Parameters 

Table 7-3 

Pollutants Detected at Average Concentrations of Less Than Five 

Times the Minimum Level During the Phase I and Phase II 

MP&M Sampling Programsa 

Priority Pollutants 

2,4,6-Trichlorophenol Chloromethane 

4,6-Dinitro-o-Cresol Dibromochloromethane 

Benzene Diethyl Phthalate 

Bromodichloromethane Tribromomethane 

Carbon Tetrachloride (Tetrachloromethane) 

Nonconventional Organic Pollutants 

2-(Methylthio)Benzothiazole n-Nitrosomorpholine 

n-Nitrosomethylethylamine o-Toluidine 

Nonconventional Metal Pollutants 

Bismuth Osmium 

Iridium Palladium 

Lithium Tantalum 

Lutetium Tungsten 

Niobium Ytterbium 

Source: MP&M Sampling Data.
 a

The average of all detected concentrations of the pollutants in samples of wastewater from proposed MP&M


operations and treatment system influent was less than five times the detection limit.


7-7

7.0 - Selection of Pollutant Parameters 

Table 7-4


Summary of Pollutants of Concern Information


Pollutant Parameter 

Phase I and Phase II Sampling Information 

No. of Times 

Analyzed for All 

Samplesa 

No. of Times 

Detected for All 

Samplesa 

Average Concentration 

in Samples of Unit 

Operation Wastewater 

and Treatment System 

Influent (mg/L)a 

Minimum 

Level 

(mg/L) 

Priority Organic Pollutants 

1,1,1-Trichloroethane 1,043 28 0.327 0.01 

1,1-Dichloroethane 1,043 7 0.091 0.01 

1,1-Dichloroethylene 1,043 3 0.418 0.01 

2,4-Dimethylphenol 994 31 0.078 0.01 

2,4-Dinitrophenol 946 4 83.7 0.05 

2,6-Dinitrotoluene 1,029 3 2.73 0.01 

2-Nitrophenol 1,021 9 0.394 0.02 

4-Chloro-m-cresol 1,003 95 260 0.01 

4-Nitrophenol 969 5 2.99 0.05 

Acenaphthene 1,029 6 0.332 0.01 

Acrolein 1,003 5 0.307 0.05 

Anthracene 1,029 4 0.117 0.01 

Bis(2-Ethylhexyl) Phthalate 1,028 211 4.15 0.01 

Benzyl Butyl Phthalate 1,026 16 1.08 0.01 

Chlorobenzene 1,043 7 0.282 0.01 

Chloroethane 1,043 4 4.22 0.05 

Chloroform 1,043 331 0.049 0.01 

Di-N-Butyl Phthalate 1,026 41 0.352 0.01 

Di-N-Octyl Phthalate 1,028 18 1.58 0.01 

Dimethyl Phthalate 994 3 0.739 0.01 

Ethylbenzene 1,043 61 0.165 0.01 

Fluoranthene 1,028 4 0.132 0.01 

Fluorene 1,029 18 0.956 0.01 

Isophorone 996 3 .056 0.01 

Methylene Chloride 1,043 52 0.403 0.01 

n-Nitrosodimethylamine 996 3 3.68 0.05 

N-Nitrosodiphenylamine 1,029 15 1.14 0.02 

Naphthalene 1,029 71 0.638 0.01 

7-8

7.0 - Selection of Pollutant Parameters 

Table 7-4 (Continued) 

Pollutant Parameter 

Phase I and Phase II Sampling Information 

No. of Times 

Analyzed for All 

Samplesa 

No. of Times 

Detected for All 

Samplesa 

Average Concentration 

in Samples of Unit 

Operation Wastewater 

and Treatment System 

Influent (mg/L)a 

Minimum 

Level 

(mg/L) 

Priority Organic Pollutants (continued) 

Phenanthrene 1,029 45 0.500 0.01 

Phenol 1,021 244 10.1 0.01 

Pyrene 1,028 5 0.219 0.01 

Tetrachloroethene 1,043 23 0.210 0.01 

Toluene 1,043 83 0.230 0.01 

Trichloroethylene 1,042 40 0.092 0.01 

Priority Metal Pollutants 

Antimony 1,956 606 6.12 0.02 

Arsenic 1,972 627 0.178 0.01 

Beryllium 1,972 301 0.147 0.005 

Cadmium 1,972 873 244 0.005 

Chromium 1,972 1,480 1,029 0.01 

Copper 1,972 1,752 495 0.025 

Lead 1,972 911 30.0 0.05 

Mercury 1,970 321 0.0014 0.0002 

Nickel 1,972 1,518 356 0.04 

Selenium 1,956 317 0.137 0.005 

Silver 1,972 698 0.531 0.01 

Thallium 1,956 206 0.065 0.01 

Zinc 1,971 1,691 188 0.02 

Conventional Pollutants 

BOD 5-Day (Carbonaceous) 1,005 757 2,015 2 

Oil and Grease (as HEM) 1,028 554 2,308 5 

Total Suspended Solids 1,959 1,563 1,007 4 

Nonconventional Organic Pollutants 

1,4-Dioxane 1,003 33 0.854 0.01 

1-Bromo-2-Chlorobenzene 989 8 0.233 0.01 

1-Bromo-3-Chlorobenzene 989 6 0.135 0.01 

1-Methylfluorene 989 24 0.347 0.01 

1-Methylphenanthrene 989 29 0.581 0.01 

2-Butanone 1,003 160 1.59 0.05 

7-9

7.0 - Selection of Pollutant Parameters 

Table 7-4 (Continued) 

Pollutant Parameter 

Phase I and Phase II Sampling Information 

No. of Times 

Analyzed for All 

Samplesa 

No. of Times 

Detected for All 

Samplesa 

Average Concentration 

in Samples of Unit 

Operation Wastewater 

and Treatment System 

Influent (mg/L)a 

Minimum 

Level 

(mg/L) 

Nonconventional Organic Pollutants (continued) 

2-Hexanone 1,003 7 1.26 0.05 

2-Isopropylnaphthalene 989 6 3.21 0.01 

2-Methylnaphthalene 989 61 0.775 0.01 

2-Propanone 1,003 593 3.14 0.05 

3,6-Dimethylphenanthrene 989 13 1.24 0.01 

4-Methyl-2-Pentanone 1,003 91 5.19 0.01 

Acetophenone 989 10 0.159 0.01 

Alpha-Terpineol 978 133 13.6 0.01 

Aniline 989 19 0.684 0.01 

Benzoic Acid 989 202 277 0.05 

Benzyl Alcohol 989 61 1.23 0.01 

Biphenyl 989 23 0.174 0.01 

Carbon Disulfide 1,003 63 0.408 0.01 

Dibenzofuran 989 4 0.055 0.01 

Dibenzothiophene 988 6 0.240 0.01 

Diphenyl Ether 989 5 0.047 0.01 

Diphenylamine 989 14 0.704 0.02 

Hexanoic Acid 989 237 15.2 0.01 

Isobutyl Alcohol 1,003 19 0.167 0.01 

m+p Xylene 595 31 0.159 0.01 

m-Xylene 408 21 0.498 0.01 

Methyl Methacrylate 1,003 6 0.396 0.01 

n,n-Dimethylformamide 989 63 0.193 0.01 

n-Decane 989 67 2.10 0.01 

n-Docosane 989 108 3.47 0.01 

n-Dodecane 989 125 13.8 0.01 

n-Eicosane 988 156 3.30 0.01 

n-Hexacosane 989 95 5.84 0.01 

n-Hexadecane 989 168 6.27 0.01 

n-Nitrosopiperidine 989 4 0.020 0.01 

n-Octacosane 989 40 7.45 0.01 

7-10

7.0 - Selection of Pollutant Parameters 

Table 7-4 (Continued) 

Pollutant Parameter 

Phase I and Phase II Sampling Information 

No. of Times 

Analyzed for All 

Samplesa 

No. of Times 

Detected for All 

Samplesa 

Average Concentration 

in Samples of Unit 

Operation Wastewater 

and Treatment System 

Influent (mg/L)a 

Minimum 

Level 

(mg/L) 

Nonconventional Organic Pollutants (continued) 

n-Octadecane 989 174 5.74 0.01 

n-Tetracosane 988 90 4.13 0.01 

n-Tetradecane 989 158 12.7 0.01 

n-Triacontane 988 55 2.69 0.01 

o+p Xylene 408 30 0.256 0.01 

o-Cresol 989 16 0.067 0.01 

o-Xylene 595 40 0.058 0.01 

p-Cresol 989 82 0.293 0.01 

p-Cymene 989 21 0.988 0.01 

Pyridine 989 37 0.920 0.01 

Styrene 989 9 0.261 0.01 

Trichlorofluoromethane 1,043 12 0.049 0.01 

Tripropyleneglycol Methyl Ether 989 141 190 0.01 

Nonconventional Metal Pollutants 

Aluminum 1,972 1,520 166 0.2 

Barium 1,972 1,651 1.75 0.2 

Boron 1,913 1,645 85.0 0.1 

Calcium 1,972 1,929 68.4 5 

Cobalt 1,972 640 12.8 0.05 

Gold 161 104 16.2 1 

Iron 1,972 1,743 777 0.1 

Magnesium 1,972 1,803 53.8 5 

Manganese 1,972 1,620 43.4 0.015 

Molybdenum 1,972 1,091 2.97 0.01 

Sodium 1,972 1,953 3,384 5 

Tin 1,912 850 153 0.03 

Titanium 1,913 949 32.6 0.005 

Vanadium 1,972 504 5.31 0.05 

Yttrium 1,913 306 0.061 0.005 

7-11

7.0 - Selection of Pollutant Parameters 

Table 7-4 (Continued) 

Pollutant Parameter 

Phase I and Phase II Sampling Information 

No. of Times 

Analyzed for All 

Samplesa 

No. of Times 

Detected for All 

Samplesa 

Average Concentration 

in Samples of Unit 

Operation Wastewater 

and Treatment System 

Influent (mg/L)a 

Minimum 

Level 

(mg/L) 

Other Nonconventional Pollutants 

Amenable Cyanide 160 128 44.3 0.02 

Ammonia As Nitrogen 689 569 385 0.05 

Chemical Oxygen Demand (COD) 1,461 1,343 11,289 5 

Chloride 677 631 5,526 1 

Fluoride 688 618 301 0.1 

Hexavalent Chromium 1,074 268 1.78 0.01 

Sulfate 1,171 1,086 7,046 1 

Total Cyanide 406 327 2,072 0.02 

Total Dissolved Solids 1,953 1,948 21,883 10 

Total Kjeldahl Nitrogen 661 572 606 1 

Total Organic Carbon (TOC) 997 838 3,385 1 

Total Petroleum Hydrocarbons 

(as SGT-HEM) 1,016 350 841 5 

Total Phosphorus 500 452 170 0.01 

Total Recoverable Phenolics 1,357 871 11.7 0.05 

Total Sulfide 215 80 6.50 1 

Weak-Acid Dissociable Cyanide 72 62 19.4 0.002 

Ziram 31 22 1.41 0.01 

Source: MP&M Sampling Data.
 a

Counts and average based on Phase I and Phase II sampling results. Sample concentrations less than the ML were


not included in the average.


parameter in samples of the unit operation wastewater or treatment system influent. Table 7-4 

also presents the average concentration at which each pollutant was detected. The Agency did 

not use sample concentrations reported as less than the ML in calculating the average. 

7.2 Regulated Pollutants 

EPA determined the pollutants for potential regulation on a subcategory basis. 

As a first step in selecting the pollutants, the Agency grouped the proposed MP&M subcategories 

(discussed in Section 6.0) according to whether the facilities in the proposed subcategory 

generated wastewater with high metals content (metal-bearing) or wastewater with low metals 

content and high oil and grease content (oil-bearing). The proposed General Metals, Metal 

Finishing Job Shops, Printed Wiring Board, Non-Chromium Anodizing, and Steel Forming and 

Finishing Subcategories generate metal-bearing wastewaters, while the Oily Wastes Subcategory 

7-12

7.0 - Selection of Pollutant Parameters 

and the proposed Railroad Line Maintenance and Shipbuilding Dry Dock Subcategories generate 

only oil-bearing wastewaters. 

Then, EPA evaluated the concentrations and prevalence of the POCs in the unit 

operations (baths and rinses) and treatment system influents for each subcategory. EPA also 

evaluated the effectiveness of the selected treatment technologies for each option (see Section 

9.0) to determine which pollutants were effectively removed by these technologies. Using this 

information, EPA considered the following factors in determining which pollutants should not be 

further considered for regulation: 

� The pollutant is controlled through the regulation of other pollutants. EPA 

evaluated wastewater treatment data to determine if control of one 

parameter would also control other pollutants. For example, most metal 

POCs are effectively removed by chemical precipitation. Control of the 

metals predominantly detected in process wastewater from proposed 

MP&M operations also controls those other metals not as common in 

process wastewater from proposed MP&M operations. Therefore, EPA 

considered only a subset of metals for regulation. In addition, many 

organic pollutants detected in process wastewater from proposed MP&M 

operations are removed in oil/water separation systems in the oil phase of 

the wastewater. Therefore, controlling the oil and grease bulk parameter 

effectively controls these organic pollutants. 

� The pollutant is present in only trace amounts in the subcategory’s 

wastewater type (metal-bearing or oil-bearing) and/or is not likely to cause 

toxic effects. EPA performed this evaluation on a pollutant-by-pollutant 

basis using the data presented in Section 5.0. 

� The pollutant may be used as a treatment chemical. 

� The pollutant is not controlled by the selected BPT/BAT technologies. 

EPA reviewed the treatment data for technologies considered in the 

MP&M technology options (see Section 9.0), and identified any pollutants 

that were not effectively removed by these technologies. 

Based on these criteria, a number of these pollutants were not further considered 

for regulation. Based on other factors, EPA established limitations and standards for direct 

dischargers in the Oily Wastes Subcategory only. For that subcategory, the list of remaining 

POCs was reduced for the purpose of setting limitations and standards to oil and grease (as 

HEM) and TSS. Table 7-5 lists all of the remaining POCs and the reason each pollutant was 

eliminated. 

EPA determined that regulating only oil and grease will control the removal of 

organic constituents for the Oily Wastes Subcategory. EPA did not promulgate a limit for total 

7-13

7.0 - Selection of Pollutant Parameters 

petroleum hydrocarbons (TPH) (as SGT-HEM) because it believes that regulating oil and grease 

(as HEM) will control the discharge of TPH (as SGT-HEM). 

EPA determined that it was not necessary to promulgate limits for 28 POCs that 

are present in only trace amounts in the Oily Wastes Subcategory and/or are not likely to cause 

toxic effects. As shown in Table 5-4, the median concentration at the influent to treatment for 

most of these metals is less than 0.5 mg/L. 

EPA did not select aluminum, calcium, iron, magnesium, manganese, sodium, 

chloride, sulfate, or total sulfide for regulation in the Oily Wastes Subcategory because they may 

be used as treatment chemicals by facilities in the Oily Wastes Subcategory. 

EPA did not select lead, zinc, barium, boron or total phosphorus for regulation in 

the Oily Wastes Subcategory because they are not controlled by the selected BPT/BAT 

technology. 

References 

1.	 U.S. Environmental Protection Agency. The 1990 Industrial Technology Division 

List of Analytes. Washington, DC, May 1990. 

2.	 U.S. Environmental Protection Agency. Development Document for Final 

Effluent Limitations Guidelines and Standards for the Centralized Waste 

Treatment Industry. (EPA-821-R-00-020), 2000. 

7-14


7.3 
7.0 - Selection of Pollutant Parameters 

Table 7-5 

Pollutants Considered for Regulation for Direct Dischargers in the Oily 

Wastes Subcategory 

Pollutant Parameter 

Controlled 

Through 

Regulation of 

Other 

Pollutants 

Present in 

Trace 

Amounts or 

Not Likely to 

Cause Toxic 

Effects 

Treatment 

Chemical 

Not Controlled 

by BPT/BAT 

Technology 

Regulated 

Under 40 CFR 

438 

Priority Organic Pollutants 

1,1,1-Trichloroethane �

1,1-Dichloroethane �

1,1-Dichloroethylene �

2,4-Dimethylphenol �

2,4-Dinitrophenol �

2,6-Dinitrotoluene �

2-Nitrophenol �

4-Chloro-m-cresol �

4-Nitrophenol �

Acenaphthene �

Acrolein �

Anthracene �

Bis(2-Ethylhexyl) Phthalate �

Benzyl Butyl Phthalate �

Chlorobenzene �

Chloroethane �

Chloroform �

Di-N-Butyl Phthalate �

Di-N-Octyl Phthalate �

Dimethyl Phthalate �

Ethylbenzene �

Fluoranthene �

Fluorene �

Isophorone �

Methylene Chloride �

n-Nitrosodimethylamine �

N-Nitrosodiphenylamine �

Naphthalene �

Phenanthrene �

7-15

7.0 - Selection of Pollutant Parameters 

Table 7-5 (Continued) 

Pollutant Parameter 

Controlled 

Through 

Regulation of 

Other 

Pollutants 

Present in 

Trace 

Amounts or 

Not Likely to 

Cause Toxic 

Effects 

Treatment 

Chemical 

Not Controlled 

by BPT/BAT 

Technology 

Regulated 

Under 40 CFR 

438 

Priority Organic Pollutants (continued) 

Phenol �

Pyrene �

Tetrachloroethene �

Toluene �

Trichloroethylene �

Priority Metal Pollutants 

Antimony �

Arsenic �

Beryllium �

Cadmium �

Chromium �

Copper �

Lead �

Mercury �

Nickel �

Selenium �

Silver �

Thallium �

Zinc �

Conventional Pollutants 

BOD 5-Day (Carbonaceous) �

Oil and Grease (as HEM) �

Total Suspended Solids �

Nonconventional Organic Pollutants 

1,4-Dioxane �

1-Bromo-2-Chlorobenzene �

1-Bromo-3-Chlorobenzene �

1-Methylfluorene �

1-Methylphenanthrene �

2-Butanone �

2-Hexanone �

2-Isopropylnaphthalene �

2-Methylnaphthalene �

2-Propanone �

7-16

7.0 - Selection of Pollutant Parameters 

Table 7-5 (Continued) 

Pollutant Parameter 

Controlled 

Through 

Regulation of 

Other 

Pollutants 

Present in 

Trace 

Amounts or 

Not Likely to 

Cause Toxic 

Effects 

Treatment 

Chemical 

Not Controlled 

by BPT/BAT 

Technology 

Regulated 

Under 40 CFR 

438 

Nonconventional Organic Pollutants (continued) 

3,6-Dimethylphenanthrene �

4-Methyl-2-Pentanone �

Acetophenone �

Alpha-Terpineol �

Aniline �

Benzoic Acid �

Benzyl Alcohol �

Biphenyl �

Carbon Disulfide �

Dibenzofuran �

Dibenzothiophene �

Diphenyl Ether �

Diphenylamine �

Hexanoic Acid �

Isobutyl Alcohol �

m+p Xylene �

m-Xylene �

Methyl Methacrylate �

n,n-Dimethylformamide �

n-Decane �

n-Docosane �

n-Dodecane �

n-Eicosane �

n-Hexacosane �

n-Hexadecane �

n-Nitrosopiperidine �

n-Octacosane �

n-Octadecane �

n-Tetracosane �

n-Tetradecane �

n-Triacontane �

o+p Xylene �

o-Cresol �

o-Xylene �

7-17

7.0 - Selection of Pollutant Parameters 

Table 7-5 (Continued) 

Pollutant Parameter 

Controlled 

Through 

Regulation of 

Other 

Pollutants 

Present in 

Trace 

Amounts or 

Not Likely to 

Cause Toxic 

Effects 

Treatment 

Chemical 

Not Controlled 

by BPT/BAT 

Technology 

Regulated 

Under 40 CFR 

438 

Nonconventional Organic Pollutants (continued) 

p-Cresol �

p-Cymene �

Pyridine �

Styrene �

Trichlorofluoromethane �

Tripropyleneglycol Methyl Ether �

Nonconventional Metal Pollutants 

Aluminum �

Barium �

Boron �

Calcium �

Cobalt �

Gold �

Iron �

Magnesium �

Manganese �

Molybdenum �

Sodium �

Tin �

Titanium �

Vanadium �

Yttrium �

Other Nonconventional Pollutants 

Amenable Cyanide �

Ammonia As Nitrogen �

Chemical Oxygen Demand 

(COD) �

Chloride �

Fluoride �

Hexavalent Chromium �

Sulfate �

Total Cyanide �

Total Dissolved Solids �

Total Kjeldahl Nitrogen �

7-18

7.0 - Selection of Pollutant Parameters 

Table 7-5 (Continued) 

Pollutant Parameter 

Controlled 

Through 

Regulation of 

Other 

Pollutants 

Present in 

Trace 

Amounts or 

Not Likely to 

Cause Toxic 

Effects 

Treatment 

Chemical 

Not Controlled 

by BPT/BAT 

Technology 

Regulated 

Under 40 CFR 

438 

Other Nonconventional Pollutants (continued) 

Total Organic Carbon (TOC) �

Total Petroleum Hydrocarbons 

(as SGT-HEM) �

Total Phosphorus �

Total Recoverable Phenolics �

Total Sulfide �

Weak-Acid Dissociable Cyanide �

Ziram �

7-19

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.0	 POLLUTION PREVENTION PRACTICES AND WASTEWATER 

TREATMENT TECHNOLOGIES 

In general, MP&M facilities generate process wastewater containing metals, 

cyanide, oil and grease, and suspended solids. Pollution prevention practices and wastewater 

treatment technologies currently used by facilities evaluated for the final rule (“MP&M 

facilities”) are designed to remove these pollutants before they are discharged to either a 

receiving stream (direct discharge) or public owned treatment works (indirect discharge). The 

type of pollution prevention practice and wastewater treatment technology a MP&M facility 

selects depends on the manufacturing operations generating the wastewater. Many facilities have 

implemented process modifications for waste reduction. Some of those modifications include 

prolonging process bath life by removing contaminants, redesigning part racks to reduce dragout, 

installing spray or fog nozzle rinse systems, and installing dragout recovery tanks (1). 

Most MP&M facilities rely on chemical precipitation and gravity or membrane 

clarification to remove metals; however, certain pretreatment techniques may be necessary when 

chelated metals or hexavalent chromium are present. Facilities that generate oily wastewater 

from operations such as machining and grinding typically use chemical emulsion breaking 

followed by gravity or membrane clarification. If cyanide is present, facilities typically use 

oxidation techniques such as alkaline chlorination. 

This section describes the pollution prevention practices and wastewater treatment 

technologies that are used by MP&M facilities, in the first instance, to prevent the generation of 

wastewater pollutants or, secondarily, to reduce the discharge of wastewater pollutants. Section 

8.1 describes flow reduction practices, Section 8.2 describes in-process pollution prevention 

technologies, Section 8.3 describes management practices for pollution prevention, Section 8.4 

describes technologies used for the preliminary treatment of waste streams, and Section 8.5 

describes end-of-pipe wastewater treatment and sludge dewatering technologies. This section 

discusses the most prevalent treatment technologies, as determined by survey responses and site 

visits, in place at facilities evaluated for the final rule. This section includes descriptions of all 

the technologies evaluated for the final rule and used as a basis for the MP&M effluent 

guidelines (see Section 9.0). Additional technologies may be applicable for some MP&M 

facilities, depending on the waste streams generated. Additionally, not all technologies discussed 

in this section are applicable to all MP&M facilities; the applicability of a technology is driven 

by the unit operations performed and waste streams generated on-site. EPA presents pollution 

prevention practices and wastewater treatment information potentially applicable to all facilities 

evaluated for the final rule (“MP&M facilities”). 

8.1 Flow Reduction Practices 

MP&M facilities applies flow reduction practices to process baths or rinses to 

reduce the volume of wastewater discharged. Flow reduction practices consist of optimizing 

rinse tank design and configuration, and installing flow reduction technologies such as flow 

restrictors or timers. Table 8-1 lists various flow reduction practices and the number 

8-1

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

observations at EPA MP&M site visits and surveys (see Section 3.0). This table also provides 

EPA’s estimate of the number of MP&M facilities employing the various flow reduction 

practices based on occurrence at surveyed facilities and their respective survey weights. The 

following subsections discuss these flow reduction practices in greater detail. 

8.1.1 Rinse Tank Design and Innovative Configurations 

Rinsing follows many proposed MP&M operations1 to remove dirt, oil, or 

chemicals remaining on parts or racks from a previous unit operation (i.e., drag-out). Rinsing 

improves the quality of the surface finishing process and prevents the contamination of 

subsequent process baths. Rinse tank design and rinsing configuration greatly influence water 

usage. The key objectives of optimal rinse tank design are to quickly remove drag-out solution 

from the part and to disperse the drag-out throughout the rinse tank. 

MP&M facilities uses various rinsing configurations. The most common are countercurrent 

cascade rinsing, drag-out rinsing, and spray rinsing. EPA estimates that over 5,000 MP&M 

facilities use at least one of these rinse schemes to reduce wastewater flow. The use of single 

overflow rinse tanks following each process tank is the most inefficient use of rinse water. 

Multiple rinse tanks connected in series (i.e., cascade rinsing) reduce the water needs of a given 

rinsing operation by one or more orders of magnitude (i.e., less water is needed to achieve the 

same rinsing quality). Spray rinsing, where the part is suspended over a tank and rinsed with 

water applied by spray nozzles, also may be used to reduce water use requirements, although less 

than countercurrent cascade rinses. Below are descriptions of some of the common rinse types. 

Cascade Rinsing 

Cascade rinsing is a method of reusing water from one rinsing operation to 

another, less critical rinsing operation before being discharged to treatment. Some rinse waters 

acquire chemical properties, such as low pH, that make them desirable for reuse in other rinse 

systems. For example, water from an acid treatment rinse may be reused in an alkaline treatment 

rinse. In this case, the rinse water both removes drag-out from the work piece and neutralizes the 

drag-out. 

1

Note: EPA evaluated a number of unit operations for the May 1995 proposal, January 2001 proposal, and June 2002 

NODA (see Tables 4-3 and 4-4). However, EPA selected a subset of these unit operations for regulation in the final 

rule (see Section 1.0). For this Section, the term “proposed MP&M operations” means those operations evaluated for 

the two proposals, NODA, and final rule. The term “final MP&M operations” means those operations defined as 

“oily operations” (see Section 1.0, 40 CFR 438.2(f), and Appendix B to Part 438) and regulated by the final rule. 

8-2 
8.0 - Pollution Prevention and Wa

Table 8-1


MP&M Flow Reduction Technologies


8-3


Technology Technology Description 

Demonstration 

Number of 

Facilities 

Visited Using 

the Technologya 

Number of 

Survey 

Facilities 

Using the 

Technology

Countercurrent Cascade 

Rinsing 

Series of consecutive rinse tanks that are plumbed to cause water to 

flow from one tank to another in the direction opposite of the work 

flow. Water is introduced into the last tank of the series, making it 

the cleanest, and is discharged from the first tank, which has the 

highest concentration of pollutants. 

110 130 

Drag-Out Rinsing Stagnant rinse, initially of fresh water, positioned immediately after 

process tanks. The drag-out rinse collects most of the drag-out from 

the process tank, preventing it from entering the subsequent flowing 

rinses. Drag-out rinse is commonly reused as make-up for heated 

process bath to replace evaporative loss. 

62 139 

Spray Rinsing Water sprayed on parts above a process tank or drip/drag-out tank; 

uses considerably less water than immersion for certain part 

configurations. This technology can also be performed as 

countercurrent cascade rinsing with spray rinses instead of overflow 

immersion rinses. 

75 187 

Flow Restrictors Equipment that prevents the flow in a pipe from exceeding a 

predetermined flow rate. Flow restrictors can be used to limit the 

flow into a rinse system. For continuously flowing rinses, a flow 

restrictor controls the flow into the system, ensuring a consistent, 

optimum flow rate. 

50 127 
8.0 - Pollution Prevention and Wa

Table 8-1 (Continued)


Technology Technology Description 

Demonstration 

Number of 

Facilities 

Visited Using 

the Technologya 

Number of 

Survey 

Facilities 

Using the 

Technology

Conductivity Probes Equipment that measures the conductivity of water in a rinse tank to 

regulate the flow of fresh rinse water into the rinse system. A 

solenoid valve on the rinse system fresh water supply is connected to 

the controller, which opens the valve when a preset conductivity 

level is exceeded and closes the valve when conductivity is below 

that level. 

40 29 

8-4


Source: MP&M site visits, MP&M sampling episodes, MP&M surveys and technical literature. Statistics specific to wastewater-discharging facilities.
aIndicates the number of MP&M facilities visited by EPA that use the listed technology. EPA visited a total of 221 facilities.
bNumber of survey facilities based on data collected in 1996 detailed survey only. The 1989 survey did not request this information. EPA sent the 1996 detailed survey cIndicates the estimated number of MP&M facilities currently performing this technology based on the 1996 detailed survey. EPA’s national estimate of the 1996 detail

approximately 4,900 facilities. EPA estimated numbers in this column using statistical weighting factors for the 1996 detailed survey respondents. See Section 3.0 for a 

of national estimates and statistical survey weights.

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Countercurrent Cascade Rinsing 

Countercurrent cascade rinsing refers to a series of consecutive rinse tanks that are 

plumbed to cause water to flow from one tank to another in the direction opposite of the work 

flow. Fresh water flows into the rinse tank located farthest from the process tank and overflows 

(i.e., cascades) into the rinse tank that is closest to the process tank. This is called countercurrent 

rinsing because the work piece and the rinse water move in opposite directions. Over time, the 

first rinse becomes contaminated with drag-out solutions and reaches a stable concentration of 

process bath constituents that is lower than the concentration in the process bath. The second 

rinse stabilizes at a lower concentration, which enables less rinse water to be used than if only 

one rinse tank were in place. The more countercurrent cascade rinse tanks (three-stage, fourstage, etc.), the less rinse water is needed to adequately remove the process solution. This differs 

from a single, overflow rinse tank where the rinse water is composed of fresh water that is 

discharged after use without any recycle or reuse. Figure 8-1 illustrates countercurrent cascade 

rinsing. 

Figure 8-1. Countercurrent Cascade Rinsing 

The rinse rate needed to adequately dilute drag-out depends on the concentration 

of process chemicals in the initial process bath, the concentration of chemicals that can be 

tolerated in the final rinse tank to meet product specifications, the amount of drag-out solution 

carried into each rinse stage, and the number of countercurrent cascade rinse tanks. These factors 

are expressed in Equation 8-1 (2): 

(8-1)


8-5

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

where: 

Vr = the flow rate through each rinse stage, gal/min; 

Co = the concentration of the contaminant(s) in the initial process bath, 

mg/L; 

Cf = the tolerable concentration of the contaminant(s) in the final rinse 

to give acceptable product cleanliness, mg/L; 

n = the number of rinse stages used; and 

VD = the drag-out carried into each rinse stage, expressed as a flow rate, 

gal/min. 

This mathematical rinsing model is based on complete rinsing (i.e., removal of all 

contaminants from the work piece) and complete mixing (i.e., homogeneous rinse water in each 

rinse stage). Under these conditions, each additional rinse stage can reduce rinse water use by 90 

percent. However, each rinse stage needs to have sufficient residence time and agitation for 

complete mixing to occur in each rinse tank to achieve these conditions. For less efficient rinse 

systems, each added rinse stage reduces rinse water use by 50 to 75 percent. 

Countercurrent cascade rinsing systems have higher capital costs than do overflow 

rinses and require more space to accommodate the additional rinse tanks. Also, when 

countercurrent cascade rinsing is used, the low flow rate through the rinse tanks may not provide 

the needed agitation for drag-out removal. In such cases, air or mechanical agitation may be 

added to increase rinsing efficiency. 

Drag-out Rinsing 

Drag-out rinse is a stagnant rinse, initially filled with fresh water, positioned 

immediately after the process tank. Work pieces are rinsed in drag-out tanks directly after 

exiting the process bath. The drag-out rinse collects most of the drag-out from the process tank, 

thus preventing it from entering the subsequent flowing rinses and reducing pollutant loadings in 

those rinses. Gradually, the concentration of process chemicals in the drag-out tank rises. In the 

most efficient configuration, a drag-out tank follows a heated process tank that has a moderate to 

high evaporation rate. A portion of the fluid in the drag-out tank returns to the process tank to 

replace the evaporative loss. The level of fluid in the drag-out tank is maintained by adding fresh 

water. Electrolytic recovery, discussed in Section 8.2.6, is commonly used to remove dissolved 

metals from drag-out tanks. 

Spray Rinsing 

For certain work piece configurations, spray rinsing uses considerably less water 

than does immersion rinsing. During spray rinsing, the parts are held over a catch tank and are 

sprayed with water. Water then drips from the part into the catch tank, and is then either recycled 

to the next stage or discharged to treatment. Spray rinsing can occur in a countercurrent cascade 

configuration, further reducing water use. Spray rinsing can enhance draining over a process 

8-6

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

bath by diluting and lowering the viscosity of the process fluid film clinging to the work piece. 

Using spray rinsing can control rinse water flow. 

8.1.2 Additional Design Elements 

In addition to rinse configuration, unit operations can be modified in other ways to 

reduce drag-out of process bath chemicals. For example, air knives and drip tanks reduce the 

pollutant loading and volume of rinse water requiring treatment. Other aspects of good rinse 

tank design include positioning the water inlet and discharge points of the tank at opposite 

locations in the tank to avoid short-circuiting, using air agitation for better mixing, using a flow 

distributor, and using the minimum tank size possible (3). Four rinse design elements are 

described in more detail below. 

Air Knives 

Air knives are high-pressure air blowers installed over a process tank or drip 

shield and are designed to remove drag-out by blowing the liquid off the surface of work pieces 

and racks and into a catch tank. Liquid from the catch tank is pumped back to the process tank. 

Air knives are most effective with flat parts and cannot be used to dry surfaces that passivate or 

stain due to oxidation. 

Drip Shields 

Drip shields are inclined sheets installed between process tanks and rinse tanks to 

recover, and drain to the process tank, process fluid that drips from racks and barrels and would 

otherwise fall into rinse tanks or onto the floor. Often, drip shields are composed of 

polypropylene or another inert material. 

Drip Tanks 

Drip tanks are installed immediately after the process tank. Work pieces exiting a 

process bath are held over the drip tank and the process fluid that drips from the work pieces 

collects in the drip tank. When enough fluid is collected in the drip tank, the fluid flows back to 

the process tank. 

Long Dwell Time 

Automatic finishing lines can be programmed to include optimum drip times. 

Long dwell times over the process tank reduce the volume of drag-out reaching the rinsing 

system. On manual lines, racks can be hung on bars over process baths to allow the fluid drip. 

Barrels can be rotated over the process bath to enhance drainage. Increases in drip time may be 

unsuitable for surfaces that can be oxidized or stained by exposure to air. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.1.3 Rinse Water Use Control 

Facilities can reduce water use by coordinating and closely monitoring rinse water 

requirements (e.g., rinse water use is optimized based on drag-out rates so that the rinse quality is 

consistent). Matching water use to rinse water requirements optimizes the quantity of rinse water 

used for a given work load and tank arrangement (3). Inadequate controlling water use negates 

the benefits of using multiple rinse tanks or other water conservation practices and results in a 

high water usage. 

Many facilities use some form of rinse water control. The four most common 

methods are flow restrictors (these can be used with other methods to regulate the rate at which 

water is dispensed), manual control (i.e., turning water valves on and off as needed), conductivity 

controls, and timer rinse controls. Using data from the 1996 MP&M industry survey, EPA 

estimates there are over 1,900 MP&M facilities using this equipment to control rinse water flow. 

These are discussed below. 

Flow Restrictors 

A flow restrictor prevents the flow in a pipe from exceeding a predetermined flow 

rate. Flow restrictors are commonly installed on a rinse tank’s water inlet. These devices contain 

an elastomer washer that flexes under pressure to maintain a constant water flow regardless of 

pressure. Flow restrictors can maintain a wide range of flow rates, from less than 0.1 gal/min to 

more than 10 gal/min. As a stand-alone device, a flow restrictor provides a constant water flow 

and is therefore best suited for continuous rinsing. For intermittent rinsing operations, a flow 

restrictor does not coordinate the rinse flow with drag-out introduction. Precise control with 

intermittent operations typically requires a combination of flow restrictors and rinse timers. 

However, for continuous rinsing (e.g., continuous electroplating machines), flow restrictors may 

be adequate for good water use control. 

Conductivity Controllers 

Conductivity controllers use conductivity probes to measure the conductivity 

(total dissolved solids (TDS)) of water in a rinse tank to regulate the flow of fresh rinse water 

into the rinse system. Conductivity controllers consist of a controller, a meter with adjustable set 

points, a probe that is placed in the rinse tank, and a solenoid valve. As parts are rinsed, 

dissolved solids enter the water in the rinse tank, raising the conductivity of the water. When 

conductivity reaches a set point where the water can no longer provide effective rinsing, the 

solenoid valve opens to allow fresh water to enter the tank. When the conductivity falls below 

the set point, the valve closes to discontinue the fresh water flow. 

In theory, conductivity control of rinse flow is a precise method of maintaining 

optimum rinsing conditions in intermittent rinsing operations. In practice, conductivity 

controllers work best with deionized rinse water. Incoming fresh water conductivity may vary 

day to day and season to season, which forces frequent set point adjustments. In addition, 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

suspended solids and nonionic contaminants (e.g., oil) can cause inadequate rinsing and are not 

measured by the conductivity probe. 

Rinse Timers 

Rinse timers are electronic devices that control a solenoid valve. The timer 

usually consists of a button that, when pressed, opens the valve for a predetermined time period, 

usually from 1 to 99 minutes. After the time period has expired, the valve automatically closes. 

The timer may be activated either manually by the operator or automatically by the action of 

racks or hoists. Automatic rinse timers are generally preferred for intermittent rinses because 

they eliminate operator error. Rinse timers installed in conjunction with flow restrictors can 

provide precise control when the incoming water pressure may rise and fall. Rinse timers are 

less effective in continuous or nearly continuous rinse operations (e.g., continuous electroplating 

machines) because the rinse operates nearly continuously. 

8.1.4 Pollution Prevention for Process Baths 

Facilities also can implement measures that will reduce or prevent pollution in 

process baths to reduce the drag-out pollutant loadings and therefore the amount of drag-out 

solution produced. Examples of these technologies are increasing bath temperature, operating at 

lower batch concentration, and using wetting agents, discussed below: 

 Temperature and viscosity are inversely related; therefore, operating a bath 

at the highest possible temperature will lower process bath viscosity and 

reduce drag-out. 

 Operating at the lowest possible concentration reduces the mass of 

chemicals in a given volume of drag-out. Also, viscosity and 

concentration are directly related; therefore, lower process bath 

concentration will result in lower process bath viscosity and less drag-out 

volume. Contaminants and other process bath impurities should be 

minimized, if possible, to extend the usefulness of the bath, reducing the 

frequency of treatment or disposal. 

 Adding wetting agents or surfactants to some process baths reduces 

viscosity and surface tension, thereby significantly reducing drag-out. 

8.2 In-Process Pollution Prevention Technologies 

This section describes in-process pollution prevention technologies used at 

MP&M facilities to reduce pollutant loadings to the wastewater treatment system. Table 8-2 lists 

a number of in-process pollutant prevention technologies. This table also provides EPA’s 

estimate of the number of MP&M facilities employing the various in-process pollutant 

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8.0 - Pollution Prevention and Wa

Table 8-2


MP&M In-Process Pollution Prevention Technologies


8-10


Technology Technology Description 

Demonstration 

Number of 

Facilities Visited 

Using the 

Technologya 

Number of 

Survey 

Facilities 

Using the 

Technology

Evaporation with 

Condensate Recovery 

Removes water by evaporation, leaving a concentrated residue for 

disposal and water vapor for condensation and reuse. 

7 15 

Ion Exchange (inprocess) Removes metal salts from electroplating rinse water using combined cation and anion exchange. Effluent (permeate) from the ion 

exchange flows back to the electroplating rinse system. Ion 

exchange regenerants are either discharged to the end-of-pipe 

chemical precipitation unit for metals removal or to electrolytic 

recovery for metals recovery. 

35 33 

Reverse Osmosis Forces wastewater through a membrane at high pressure, leaving a 

concentrated stream of pollutants for disposal. Reverse osmosis may 

provide an effluent clean enough for reuse. 

3 1 

Centrifugation of Painting Water 

Curtains 

Removes the heavier solids from the water curtain by centrifugation, 

allowing the water to be reused. The solids are collected as a cake in 

the basket of the centrifuge. This technology can achieve closed-loop 

reuse of water curtains. 

3 1 

Filtration of Painting 

Water Curtains 

Removes solids by filtration (cloth, sand, diatomaceous earth, etc.) 

followed by reuse. This technology can achieve closed-loop reuse of 

water curtains. 

2 3 

Settling of Painting 

Water Curtains 

Removes the heavier solids from the water curtains by gravity 

separation. This technology can be used in conjunction with other 

removal technologies to lessen the solids loading. 

5 5 

Biocide Addition to 

Lengthen Coolant Life 

Can impede the growth of microorganisms that cause rancidity. 

Machining coolant is often discarded as it becomes rancid. 

9 27 

Centrifugation of Machinery Coolant 

Removes the solids from the coolant by centrifugation to extend its 

usable life. Some high-speed centrifuges can also perform liquid-liquid 

separation to remove tramp oils and further extend coolant life. 

18 10 
8.0 - Pollution Prevention and Wa

Table 8-2 (Continued)


Technology Technology Description 

Demonstration 

Number of 

Facilities Visited 

Using the 

Technologya 

Number of 

Survey 

Facilities 

Using the 

Technology

Filtration of Machinery 

Coolant 

Removes the solids from the coolant using filters such as cloth, sand, or 

carbon to extend its usable life. 

18 18 

Skimming of Tramp 

Oils in Machinery 

Coolants 

Removes tramp oils using mechanical skimming to extend coolant 

life. Tramp oil buildup often makes machining coolant unusable. 

8 9 

Pasteurization of 

Machinery Coolants 

Kills the microorganisms that cause rancidity using heat. Machining 

coolant is often discarded as it becomes rancid. 

2 2 

General Filtration of 

Baths and Solutions 

Removes metals and other impurities from process tanks, including 

electrolytic plating solutions and acid/alkaline cleaning tanks. 

Increases bath longevity. Technologies include paper filters, carbon 

adsorption, and magnetic separators. 

6 

Electrolytic Recovery 

(Electrowinning) 

Recovers dissolved metals from concentrated sources using an 

electrochemical process. For rinses, electrolytic recovery is typically 

restricted to drag-out rinses. Flowing rinses are generally too dilute 

for efficient electrolytic recovery. This technology effectively 

recovers metals from ion exchange regenerants. 

22 23 

8-11


Source: MP&M site visits, MP&M sampling episodes, MP&M surveys and technical literature. Statistics specific to wastewater-discharging facilities.
aIndicates the number of MP&M facilities visited by EPA that use the listed technology. EPA visited a total of 221 facilities.
bNumber of survey facilities based on data collected in 1996 detailed survey only. The 1989 survey did not request this information. EPA sent the 1996 detailed survey cIndicates the estimated number of MP&M facilities currently performing this technology based on the 1996 detailed survey. EPA’s national estimate of the 1996 detai

approximately 4,900 facilities. EPA estimated numbers in this column using statistical weighting factors for the 1996 detailed survey respondents. See Section 3.0 for 

of national estimates and statistical survey weights.

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

prevention technologies based on occurrence at surveyed facilities and their respective survey 

weights. In-process pollution prevention technologies can be applied to process baths or rinses. 

Not all technologies discussed in this subsection are applicable to all MP&M facilities. 

Process baths become contaminated with impurities that affect their performance. 

The sources of process bath contamination include: (1) breakdown of process chemicals; 

(2) buildup of by-products (e.g., carbonates); (3) contamination from impurities in make-up 

water, chemicals, or anodes; (4) corrosion of parts, racks, tanks, heating coils, etc.; (5) drag-in of 

chemicals; (6) errors in bath additions; and (7) airborne particles entering the tank. If not 

properly maintained, process baths become prematurely unusable and require disposal. 

Regeneration and maintenance techniques help keep baths in good operating condition, thereby 

extending the useful lives of process solutions. Using these technologies reduces the frequency 

of process bath discharges, and therefore reduces pollutant loadings to the wastewater treatment 

system. This, in turn, reduces wastewater treatment requirements and sludge disposal costs. 

Rinsing removes residual process chemicals from the surface of a work piece. As 

more and more work pieces are rinsed, the concentration of process chemicals (contaminants) in 

the rinse water increases. At some point, the concentration of process chemicals in the rinse 

water becomes so high that an unacceptable amount of process chemicals remain on the surface 

of the work piece. When this occurs, clean water is added to the rinse solution to lower the 

concentration of process chemicals to a level that will not impact the quality of the work piece. 

Overflow from the rinsing operation goes to treatment for removal of the residual process 

chemicals. For continuous processing operations, clean water may continuously flow into the 

rinse process to ensure that the concentration of contaminants will not exceed the quality limit 

for the work piece. 

This section describes the following technologies used to treat and reuse process 

solutions: 

� Activated carbon adsorption;


� Carbonate freezing;


� Centrifugation and pasteurization of machining coolants;


� Centrifugation and recycling of painting water curtains;


� Electrodialysis;


� Electrolytic recovery;


� Evaporation;


� Filtration;


� Ion exchange; and


� Reverse osmosis.


8.2.1 Activated Carbon Adsorption 

Activated carbon adsorption is a common method of removing organic 

contaminants from electroplating baths. Process solution flows through a filter where the carbon 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

adsorbs organic impurities that result from the breakdown of bath constituents. Carbon 

adsorption can be either a continuous or batch operation, depending on the site’s preference. 

Carbon treatment is most commonly applied to nickel, copper, zinc, and cadmium electroplating 

baths but also can be used to remove organic contaminants from paint curtains. 

8.2.2 Carbonate “Freezing” 

Carbonate “freezing” removes excessive carbonate buildup by forming carbonate 

salt crystals at a low temperature that are then removed. MP&M facilities most often apply this 

process to electroplating baths formulated with sodium cyanide. Carbonates build up in the 

process bath by the breakdown of cyanide (especially at high temperatures) and the adsorption of 

carbon dioxide from the air. An excessive carbonate concentration reduces the product quality of 

many metal finishing operations. Carbonate “freezing” takes advantage of the low solubility of 

carbonate salts in the sodium cyanide bath. The method lowers the bath temperature to 

approximately 26°F (-3°C), at which point hydrated salt (Na2CO3•10H2O) crystallizes out of 

solution. The crystallized carbonate can be removed by decanting the fluid into another tank or 

by filtration. 

8.2.3 Centrifugation and Pasteurization of Machining Coolants 

Most machining coolants contain water-soluble oil in water. The water-soluble 

coolant typically is pumped from a sump, over the machining tool and work piece during 

machining, and back to the sump. Over a period of time, recycled coolant becomes ineffective, 

or spent, for one or more of the following reasons: 

� The concentration of suspended solids in the coolant begins to inhibit 

performance; 

� Nonemulsified, or “tramp,” oil collects on the surface of the coolant, 

inhibiting performance; 

� The coolant becomes rancid due to microbial growth; or 

� Coolant additives are consumed by drag-out and organic breakdown, thus 

reducing corrosion prevention and lubrication properties. 

As shown in Table 8-2, EPA estimates that nearly 300 MP&M facilities use centrifugation and 

biocide/pasteurization processes to extend the life of their water-soluble coolants. 

Coolant recycling is most effective when facilities minimize the number of 

different coolants used on-site and use a centralized coolant recycling system. However, some 

facilities may not be able to use a single recycling system because of multiple coolant types 

required by product or customer specifications. In this case, facilities may need to purchase 

dedicated coolant recycling systems for each type of coolant used. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Using a centrifugal separator and pasteurization unit can extend the useful life of 

machining coolants. The separator is a rotating chamber that uses centrifugal force to push the 

coolant through a mesh chamber, leaving behind solid contaminants of sludge. Sludge is scraped 

from the centrifuge and collected in a sludge hopper. Some high-speed centrifuges also can 

perform liquid-liquid separation to remove tramp oils. The coolant undergoes pasteurization 

after separation to kill the microorganisms that cause bacterial growth. Adding a biocide can 

also control bacterial growth. Figure 8-2 shows a diagram of a typical machine coolant recycling 

system. 

Figure 8-2. Machine Coolant Recycling System 

Centrifugal separators are very reliable and require only routine maintenance, such 

as periodic cleaning and removal of accumulated solids. Flow rate is the primary operating 

factor to control. The sludge generated from this technology is commonly classified as a 

hazardous waste, based on the metal type processed and the amount of metal that dissolves into 

the coolant. Facilities typically haul the sludge off-site for treatment and disposal. 

Centrifugation and pasteurization can be used in conjunction with oil skimming 

and biocide addition to reduce coolant discharge and pollutant generation at the source. Oil 

skimming using a vertical belt system (described in Section 8.4.5.2) removes large amounts of 

tramp hydraulic oils floating on the surface of the machine coolant. Oil skimming and biocide 

addition can further extend the life of water-soluble coolant, thereby reducing the amount of 

coolant and wastewater requiring treatment and disposal, and minimizing fresh coolant 

requirements. 

8.2.4 Centrifugation and Recycling of Painting Water Curtains 

Water curtains are a continuous flow of water behind the work piece being spray 

painted in a paint booth. The water traps paint overspray and is continuously recirculated in the 

paint curtain until the solids content in the wastewater necessitates either in-process treatment 

and recycling or discharge. Based on data from the 1996 MP&M detailed survey, approximately 

12 MP&M facilities centrifuge and recycle water from their paint curtains. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Wastewater from painting water curtains commonly contains organic pollutants as 

well as certain metals. Eliminating the discharge of wastewater from painting water curtains may 

eliminate the need for an end-of-pipe treatment step for organic pollutants at certain facilities. 

Moreover, if a facility uses only painting water curtains and continuously recycles the water, the 

facility would not need end-of-pipe wastewater treatment. 

Figure 8-3 shows a diagram of a typical in-process centrifugation and recycling 

treatment system for a paint curtain. Centrifugal separators remove the solids and recycle the 

water curtain, eliminating the need for discharge. This system can recycle, the paint curtain 

water continuously. The system pumps the water curtain from the paint curtain sump to a 

holding tank, then through the centrifugal separator, which separates the solids from the 

wastewater (see section 8.2.3). Solids from the centrifuge are hauled for off-site disposal, while 

the treated wastewater is returned to the paint booth. Centrifugation of the paint curtain proceeds 

until all wastewater is treated and only sludge remains in the paint curtain sump. Operators must 

remove the sludge in the paint curtain sump either manually, with a sludge pump, or by vacuum 

truck. The facility may add detactifiers before centrifugation to increase the solid separation 

efficiency. Detactifiers make the paint solids less sticky, allowing them to be more easily 

removed from the centrifuge. Make-up water is added to the system to compensate for 

evaporation. 

Figure 8-3. Centrifugation and Recycling of Painting Water Curtains 

As discussed in Section 8.2.3, centrifugal separators are very reliable and require 

only routine maintenance. Flow rate is the primary operating factor to control. One disadvantage 

of this technology is that it may not be economically feasible for facilities generating only a small 

amount of paint curtain wastewater. Facilities that have multiple sumps can use portable 

centrifuges. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

The sludge generated from painting water curtains is commonly classified as a 

hazardous waste, based on the type of paint used, and typically is hauled off-site for treatment 

and disposal. See Appendix D for more information on pollution prevention practices with 

painting operations. 

8.2.5 Electrodialysis 

Electrodialysis is a process in which dissolved colloidal species are exchanged 

between two liquids through selective semipermeable membranes (11). The technology applies a 

direct current across a series of alternating anion and cation exchange membranes to remove 

dissolved metal salts and other ionic constituents from solutions. 

An electrodialysis unit consists of a rectifier and a membrane stack. The rectifier 

converts alternating current to direct current. The stack consists of alternating anion- and cationspecific membranes that form compartments. As the feed stream enters the unit, ions move 

across the electrodialysis membranes, forming a concentrated stream and a deionized stream. 

When the compartments are filled, a direct current is applied across each membrane in the stack. 

Cations traverse one cation-specific membrane in the direction of the cathode and are trapped in 

that concentrate compartment by the next membrane, which is anion-specific. Anions from the 

neighboring compartment traverse the anion-specific membrane in the direction of the anode, 

joining the cations, and are likewise trapped in the concentrate compartment by the next cationspecific membrane. In this way, the technology depletes the feed stream of ions, and traps anions 

and cations in each concentrate compartment. Facilities typically use electrodialysis to remove 

metal ions from electroplating wastewater. Figure 8-4 shows a diagram of an electrodialysis cell. 

8-16

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Figure 8-4. Electrodialysis Cell 

By using the electrodialysis cell, facilities remove impurities from the process 

bath, extending its life. Facilities can treat the removed concentrate stream on-site, or haul it offsite for disposal, treatment, or metals reclamation. 

8.2.6 Electrolytic Recovery 

Electrolytic recovery is an electrochemical process used to recover metal 

contaminants from many types of process solutions and rinses, such as electroplating rinse waters 

and baths. Electrolytic recovery removes metal ions from a waste stream by processing the 

stream in an electrolytic cell, which consists of a closely spaced anode and cathode. Equipment 

consists of one or more cells, a transfer pump, and a rectifier. Current is applied across the cell 

and metal cations are deposited on the cathodes. The waste stream is usually recirculated 

through the cell from a separate tank, such as a drag-out recovery rinse. 

Facilities typically apply electrolytic recovery to solutions containing either 

nickel, copper, precious metals, or cadmium. Chromium cannot be electrolytically recovered 

because it exists primarily in anionic forms such as dichromate. Drag-out rinses and ionexchange regenerant are solutions that commonly are processed using electrolytic recovery. 

Some solutions require pH adjustment prior to electrolytic recovery. Acidic, metal-rich, cation 

regenerant is an excellent candidate stream for electrolytic recovery and is often electrolytically 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

recovered without pH adjustment. In some cases, when the target metal concentration is reached, 

the waste stream can act as cation regenerant. 

The capacity of electrolytic recovery equipment depends on the total cathode area 

and the maximum rated output of the rectifier. Units are available with a cathode area ranging 

from 1 ft2 to 100 ft2 or larger, and an output of 10 to 1,000 amperes or more. Faraday’s law, 

which states the amount of chemical change produced by an electric current is proportional to the 

quantity of electricity used, determines theoretical electrolytic recovery rates. Theoretical 

recovery rates range from 1.09 grams/amp-hour for nickel to 7.35 grams/amp-hour for 

monovalent gold. Actual rates are usually much lower and depend on the metal concentration in 

the waste stream. At concentrations under 100 mg/L, electrolytic recovery rates may be below 10 

percent of the theoretical maximum. 

Electrolytic recovery units use various types of cations, depending mainly on the 

concentration of metal in the waste stream. Cathodes are often classified by their surface area. 

Flat-plate cathodes have the lowest surface area and are used only for recovering metal from 

metal-rich waste streams (usually 1,000 to 20,000 mg/L of metal). Reticulate cathodes, which 

have a metallized woven fiber design, have a surface area 10 times greater than their apparent 

area. These cathodes are effective over a wide range of metal concentrations but typically are 

used where the dissolved metal concentration is below 100 mg/L. Carbon and graphite cathodes 

have the highest surface area per unit of apparent area. Their use is usually restricted to metal 

concentrations below 1,000 mg/L. 

Reticulate or carbon cathodes can recover metals in electrolytes to concentrations 

as low as 5 mg/L. Electrolytes are substances that dissociate into ions in solution (i.e., water), 

thereby becoming electrically conducting (4). In practice, however, the target effluent 

concentration for most applications is 50 to 250 mg/L or higher because of the time and energy 

required to achieve concentrations less than 100 mg/L. With flat-plate cathodes, the target 

effluent concentration is usually above 500 mg/L, because plating efficiency drops as 

concentration falls. Plating time required to lower the concentration of a pollutant from 100 to 

10 mg/L can be several times longer than that required to lower the concentration from 10,000 

mg/L to 100 mg/L. Also, unit energy costs (measured in dollars per pound of metal recovered) 

increase substantially at lower metal concentrations. 

Electrolytic recovery units have relatively low labor requirements. Units 

recovering dissolved metal from drag-out rinse tanks only may require occasional cleaning and 

maintenance. Units treating batch discharges from ion-exchange units (see Section 8.2.8.1) 

require more labor due to the higher metal content of the solution and the resultant increase in 

cathode loading frequency. Energy costs for this technology can be high, and, in some cases, 

exceed the recovery value of the metal. Energy requirements depend on several factors, 

including required voltage, rectifier efficiency, and current efficiency. In addition, from an 

energy standpoint, electrolytic recovery removes metals from concentrated solutions more 

efficiently than from dilute solutions. Electrode replacement costs may be significant for units 

8-18

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

using disposable cathodes, especially for high metal recovery rates. However, if electrodes are 

constructed properly, cathodes and anodes may last more than five years for most applications. 

Numerous vendors offer electrolytic recovery technology. The technology is 

applicable to a wide range of processes, drag-out rinses, and ion-exchange regenerants due to the 

diversity of materials and configurations available for anodes and cathodes. Electrolytic recovery 

is not applicable to flowing rinses due to the lower metal concentrations and the extended time 

required for metal recovery. In most cases, this technology cannot cost-effectively remove 

dissolved metals to concentrations required for discharge to POTWs or surface waters. 

8.2.7 Evaporation

Evaporation is a volume reduction and water recovery technology applicable 

when raw water costs are high or discharge to either a receiving stream or the local sewerage 

district is not permitted. EPA estimates there are 147 MP&M facilities using evaporation to 

reduce the volume of their waste and to recover and reuse their water. Evaporators have the 

potential to recover 95 percent of the water in a waste stream for reuse in the process. MP&M 

facilities use two basic types of evaporators: atmospheric and vacuum. Atmospheric evaporators 

are more prevalent and are relatively inexpensive to purchase and easy to operate. Vacuum 

evaporators are mechanically more sophisticated and are more energy-efficient. Facilities 

typically use vacuum evaporators when evaporation rates greater than 50 to 70 gallons per hour 

are required. MP&M facilities use evaporators to recover metals from ion exchange regenerates, 

to reduce the volume of oily wastes that require off-site transfer, and to recover and reuse rinse 

water from plating operations. 

Equipment required for evaporation systems include (12): 

� Basket strainers in lift stations and sumps to prevent items like shop rags 

from reaching the evaporator; 

� Equalization tanks to handle batch dumps of process water; 

� An oil skimmer in the equalization tank to remove floatable oil; 

� Evaporators (either vacuum or atmospheric); 

� Residue holding tanks; 

� Air pollution control equipment; 

� A condenser to capture water vapor for return to the manufacturing 

process; and 

� Natural gas or propane tanks for evaporator fuel storage. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Residue from evaporators can be recycled if sufficiently pure, disposed of off-site, or used for 

energy recovery if the material has a sufficient BTU content. 

8.2.8 Filtration

Filtration removes suspended solids from surface finishing operations. EPA 

estimates there are nearly 150 MP&M facilities that use filters on their machining and grinding 

operations to remove solids, debris, or swarf from machining coolants. If solids are not removed 

from machining coolants, they may cause a rough or burred surface on the work piece. Filtered 

coolants return to the manufacturing process. In-process filtration extends the life of the coolant 

and reduces the amount of oil and grease sent to treatment. Filtration equipment includes 

cartridge filters, precoat diatomaceous earth filters, sand, and multimedia filters. 

Cartridge filters are available with either in-tank or external configurations. The 

in-tank units are used mostly for small tanks and the external units for larger tanks. Most 

cartridges are disposable; however, washable and reusable filters are available, which further 

reduce waste generation. Precoat, sand, and multimedia filters are used mostly for large tanks. 

The filter media used depends on the chemical and physical characteristics of the bath, which 

determine the filter material type, density, nominal micron retention, wet strength, mullen burst, 

and air permeability. Material type is important to ensure the media is compatible with the liquid 

being filtered. Media density is how close or dense the media fibers are laid, laminated, or 

woven. Nominal micron retention indicates the smallest particle size the media will retain to 

develop a filter cake. Flux rate through the filter is determined by the air permeability 

characteristics. All filtration systems are sized based on solids loading and the required flow 

rate. 

Membrane filtration also can remove oils and metals from process baths or rinses, 

and remove solids from paint curtains or tramp oils from machine coolants to extend usable life. 

They are also commonly used to recover and recycle electrophoretic painting (“e-coat”) 

solutions. Membrane filtration is a pressure-driven process that separates solution components 

based on molecular size and shape. Solvent and small solutes can pass through the membrane 

while the membrane retains and collects larger compounds as a concentrated waste stream. The 

cleaner permeate can be reused in the process while the concentrated waste stream is discharged 

to treatment. Figure 8-5 shows a typical membrane filtration unit. 

8-20

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Figure 8-5. Membrane Filtration Unit

8.2.8.1 Ion Exchange (in-process)

Ion exchange is a commonly used technology within MP&M facilities. In 

addition to water recycling and chemical recovery applications, ion exchange is used to soften or 

deionize raw water for process solutions. Figure 8-6 shows a typical ion-exchange system. 

Ion exchange is a reversible chemical reaction that exchanges ions in a feed 

stream for ions of like charge on the surface of an ion-exchange resin. Resins are broadly 

divided into cationic or anionic types. Typical cation resins exchange H+

 for other cations, while 

anion resins exchange OH- for other anions (10). 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Figure 8-6. Ion Exchange

A feed stream passes through a column, which holds the resin. The feed stream is 

usually either dilute rinse water (in-process ion exchange) or treated wastewater (end-of-pipe ion 

exchange). Often, prior to ion-exchange treatment, the feed stream passes through a cartridge 

filter and a carbon filter to remove suspended solids and organic pollutants that foul the resin 

bed. The exchange process continues until the capacity of the resin is reached (i.e., an exchange 

has occurred at all the resin sites). A regenerant solution then passes through the column. For 

cation resins, the regenerant is an acid, and the H+

 ions replace the cations captured from the feed 

stream. For anion resins, the regenerant is a base, and OH- ions replace the anions captured from 

the feed stream. The metals concentration is much higher in the regenerant than in the feed 

stream; therefore, the ion-exchange process not only separates the metals from the waste stream 

but also results in a more concentrated waste stream. 

MP&M facilities use ion exchange for water recycling and metal recovery. For 

water recycling, cation and anion columns are placed in series. The feed stream is deionized and 

the product water is reused for rinsing. Often, the system can achieve closed-loop rinsing. The 

regenerant from the cation column contains metal ions, which are recoverable in elemental form 

via electrolytic recovery (see Section 8.2.6). The anion regenerant typically flows to wastewater 

treatment. Facilities use this type of ion exchange to recycle relatively dilute rinse streams. 

Generally, the TDS concentration of such streams must be below 500 mg/L to maintain an 

8-22

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

efficient regeneration frequency. Reducing drag-out can enhance the efficiency of the recovery 

process. Effluent TDS concentrations of 2 mg/L or less are typical. 

When facilities are seeking only metal recovery, they use a single or double cation 

column unit containing selective resin. These resins attract divalent cations while allowing 

monovalent cations to pass, a process usually called metal scavenging. This technology is 

efficient if the metal ions being scavenged are the primary source of ions in the stream. Ion 

exchange provides effective metals recovery even when the metal content of the stream is only a 

small fraction of the TDS present in the stream, making scavenging suitable over a wider range 

of TDS than water recycling. Scavenging also provides a highly concentrated regenerant, 

particularly suitable for electrolytic recovery (see Section 8.2.6). Water recycling using this ion 

exchange configuration is not possible because only some of the cations and none of the anions 

are removed. Standard units typically achieve effluent metal concentrations of under 0.5 mg/L. 

Many process wastewaters are excellent candidates for ion exchange, including 

the rinse water from plating processes of chromium, copper, cadmium, gold, lead, nickel, tin, tinlead, and zinc. Ion exchange resins usually are regenerated using inexpensive chemicals such as 

sulfuric acid and sodium hydroxide. Gold-bearing resins are difficult to regenerate and 

frequently require incineration to recover the gold content. Lead also is difficult to recover from 

ion exchange resins. Methane sulfonic acid and fluoboric acid (usually not suitable for 

electrolytic recovery) are effective regenerants for lead ion exchange but are very expensive. 

Cyanide rinse waters are amenable to ion exchange; cation resins can break the metal-cyanide 

complex and the cyanide is removed in the anion column. The metals in the cation regenerant 

can be recovered electrolytically and the cyanide present in the anion regenerant can be returned 

to the process or discharged to treatment. 

Ion-exchange equipment ranges from small, manual, single-column units to multicolumn, highly automated units. Two sets of columns are necessary for continuous treatment; 

one set receives the wastewater flow while the other set is being regenerated. Thus, two-column 

metal scavenging and four-column deionizing systems are common. Automatic systems direct 

the wastewater flow and initiate regeneration with little or no operator involvement. 

The labor requirements for ion exchange depend on the automation level of the 

equipment. Manual systems can have significant labor costs associated with preparing, 

transporting, and disposing of regenerants. Automatic systems require far less labor. Resins 

need to be replaced periodically due to organic contamination, resin oxidation, and fouling from 

suspended solids. This process can be hastened by misuse, accidents, or poor engineering. 

Equipment size is based on flow rate and concentration. Resin capacity varies but 

often ranges from 1 to 2 lbs/ft3

. Flow rates may range from 1 to 20 or more gpm. Columns 

typically are sized to handle wastewater flow for at least a period of time equal to that required 

for regeneration. Automatic systems are sized to provide continuous treatment. Regeneration 

volume typically ranges from 2 to 4 resin bed volumes of dilute acid or caustic. Concentrations 

of feed stream contaminants generally range from 10 to 20 g/L. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.2.8.2 Reverse Osmosis 

Reverse osmosis is a membrane separation technology used by MP&M facilities 

for chemical recovery and water recycling. The system pumps dilute rinse water to the surface of 

the reverse osmosis membrane at pressures of 400 to 1,000 pounds per square inch gauge (psig). 

The membrane separates the feed stream into a reject stream and a permeate. The reject stream, 

containing most of the dissolved solids in the feed stream, is retained by the membrane while the 

permeate passes through. Reverse osmosis membranes reject more than 99 percent of 

multivalent ions and 90 to 96 percent of monovalent ions, in addition to organic pollutants and 

nonionic dissolved solids. The permeate stream usually is of sufficient quality to be recycled as 

rinse water, despite the small percentage of monovalent ions (commonly potassium, sodium and 

chloride) that pass through the membrane. Reverse osmosis equipment is similar to the 

equipment shown in Figure 8-5. 

A sufficiently concentrated reject stream can be returned directly to the process 

bath. Recycling the stream through the unit more than once or by increasing the feed pressure 

can increase the reject stream concentration. In multiple-stage units containing more than one 

membrane chamber, the reject stream from the first chamber is routed to the second, and so on. 

The combined reject streams from multistage units may, in some cases, have high enough 

concentrations to go directly back to the bath. 

The capacity of reverse osmosis equipment generally is measured in flow volume, 

and is determined by the membrane surface area and operating pressure. Increasing the surface 

area of the membrane usually increases the membrane capacity. Operating at higher pressures 

increases the permeate flow volume per unit membrane area (also called the flux). Reject stream 

concentration increases with pressure and decreases as flow volume increases. 

Facilities may need to prefilter and pretreat the feed stream to lengthen membrane 

life or reduce the frequency of fouling; filtration to remove suspended solids is usually necessary. 

Adjusting pH may prevent precipitation as the feed stream is concentrated, but it may make the 

concentrate unfit to return to the process bath. 

Reverse osmosis is most applicable to electroplating rinse waters, including 

electroplating of Watts nickel, bright nickel, brass cyanide, copper cyanide, and zinc cyanide. 

This technology can treat TDS concentrations of up to 1,000 mg/L. Permeate TDS 

concentrations of 250 mg/L or less are typical, and the dissolved solids are mostly commonly 

monovalent ions, allowing the permeate stream to be reused in many rinsing operations. 

The maximum achievable reject stream concentration for basic reverse osmosis 

equipment is approximately 20,000 mg/L TDS. Multipass and multistage units achieve 

concentrations of 30,000 mg/L TDS or higher. If the reject stream is acceptable to return directly 

to the process bath and the permeate is recycled as rinse water, a closed loop is created. 

However, returning the reject stream directly to the bath is uncommon because the concentration 

is often too low. When the reject stream concentration is not high enough to return it to the bath, 

8-24

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

it can be concentrated with an evaporator, electrolytically recovered, or discharged to wastewater 

treatment. When evaporators are used, however, reverse osmosis loses its low-energy advantage 

over other in-process reuse and recovery technologies. 

Reverse osmosis often has a higher capital cost than does ion exchange when both 

technologies include an electrolytic recovery unit. When used for water recycling, reverse 

osmosis and ion exchange both remove similar quantities of metals; however, reverse osmosis 

may allow for more water recycling.. During reverse osmosis, only the pumps use energy. In 

most cases, water is recycled; in some cases, a closed loop is possible. Compared to ion 

exchange, reverse osmosis can treat somewhat higher feed stream concentrations. The 

concentration of reverse osmosis reject streams are near or higher than that of ion-exchange 

regenerants. Both are less effective in handling oxidizing chemistries or feed streams high in 

organic compounds and total suspended solids. Ion-exchange effluent generally has a lower TDS 

concentration than does reverse osmosis permeate and can be recycled in most rinses. 

For most applications, reverse osmosis membranes last for one to five years, 

although they are susceptible to fouling from organic pollutants, suspended solids, or misuse. 

Reverse osmosis units may be able to track the condition of the membrane by measuring the flux. 

If the membrane fouls or clogs, the flux rate drops, indicating that the membrane should be 

cleaned. Labor associated with operating reverse osmosis equipment is for periodic membrane 

cleaning. Membrane and pump replacement are the primary maintenance items. 

Best Management Practices and Environmental Management Systems for 

Pollution Prevention 

EPA encourages the wide spread use of Best Management Practices (BMPs), and 

Environmental Management Systems (EMS), to achieve improved environmental performance 

and compliance, pollution prevention through source reduction, and continual improvement (see 

EPA Position Statement on Environmental Management Systems, May 15, 2002, DCN 17848, 

Section 24.4). However, as described in the Section IV of the preamble to the final rule, EPA is 

not requiring the use of BMPs or EMSs for compliance with the MP&M effluent guidelines. 

Best Management Practices (BMPs) are inherently pollution prevention practices. 

BMPs may include the universe of pollution prevention encompassing production modifications, 

operational changes, material substitution, materials and water conservation, and other such 

measures (17). BMPs include methods to prevent the discharge of toxic and hazardous 

pollutants. BMPs are most effective when organized into a comprehensive facility EMS. 

MP&M facilities employ many types of pollution prevention measures including 

the following: training and supervision; production planning; process or equipment modification; 

raw material and product substitution or elimination; loss prevention and housekeeping; waste 

segregation and separation; and closed-loop recycling. These practices are discussed in further 

detail below (1). 

8-25


8.3 
8.0 - Pollution Prevention and Wastewater Treatment Technologies 

� Training and Supervision 

Training and supervision ensure that employees are aware of, understand, 

and support the company’s pollution prevention goals. Effective training 

programs translate these goals into practical information that enables 

employees to minimize waste generation by properly and efficiently using 

tools, supplies, equipment, and materials. 

� Production Planning 

Production planning can minimize the number of process operation steps 

and eliminate unnecessary procedures (e.g., production planning can 

eliminate additional cleaning steps between process operations). 

� Process or Equipment Modification 

Facilities can modify processes and equipment to minimize the amount of 

waste generated (e.g., changing rack configuration to reduce drag-out). 

� Raw Material and Product Substitution or Elimination 

Where possible, facilities should replace toxic or hazardous raw materials 

or products with other materials that produce less waste and less toxic 

waste (e.g., replacing chromium-bearing solutions with non-chromiumbearing and less toxic solutions, or consolidating types of cleaning 

solutions and machining coolants). 

� Loss Prevention and Housekeeping 

Loss prevention and housekeeping includes performing preventive 

maintenance and managing equipment and materials to minimize leaks, 

spills, evaporative losses, and other releases (e.g., inspecting the integrity 

of tanks on a regular basis; using chemical analyses instead of elapsed 

time or number of parts processed as the basis for disposal of a solution). 

� Waste Segregation and Separation 

Facilities should avoid mixing different types of wastes or mixing 

hazardous wastes with nonhazardous wastes. Similarly, facilities should 

not mix recyclable materials with noncompatible materials or wastes. For 

example, facilities can segregate scrap metal by metal type, separate 

cyanide-bearing wastewater for preliminary treatment, and segregate 

coolants for recycling or treatment. 

� Closed-Loop Recycling 

Facilities can recover and reuse some process streams. For example, some 

facilities can use ion exchange to recover metal from electroplating rinse 

water, reuse the rinse water, and reuse the regenerant solution as process 

solution make-up. 

8-26

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

The following sections describe pollution prevention opportunities for a few 

MP&M facilities. 

8.3.1 Pollution Prevention for Cleaning and Degreasing Operations 

The majority of facilities in the Oily Wastes Subcategory perform cleaning and 

degreasing operations to remove residual oil and coolants from metal parts following machining 

and grinding operations. These facilities also perform cleaning and degreasing on equipment 

undergoing maintenance. Opportunities to reduce waste from these operations include process 

elimination, material substitution, in-process recycling, waste segregation, maintenance/ 

housekeeping, procedures/scheduling, and equipment layout/piping/automation. Examples of 

these opportunities are presented below (15). 

Process Elimination 

� Determine whether parts need to be cleaned; 

� Use easy-to-clean or no-clean rust inhibitors and lubricants; 

� Review the parts-handling process to determine why parts are getting dirty, 

and take action to prevent it from happening in the future; and 

� Purchase clean input stock.


Material Substitution


� Clean by brushing and wiping where possible;


� Use aqueous-based cleaners;


� Use solvents with low vapor pressure and high flash point; and


� Use citrus or terpene cleaners.


In-Process Recycling


� Use countercurrent rinsing;


� Skim/filter and reuse aqueous cleaners;


� Reuse solvents by installing filtration or distillation units; and


� Install a bioremediation parts washer that uses enzymes to remove oil and 

grease. 

8-27

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Waste Segregation 

� Segregate solvents to allow recycling; 

� Keep solvents out of waste oil; 

� Keep fuel, brake fluid and other fluids out of solvents to prevent the 

mixture from becoming hazardous; and 

� Keep solvents out of aqueous cleaners.


Maintenance/Housekeeping


� Use secondary containment for solvent storage; and


� Implement a maintenance program to fix and prevent leaks.


Procedures/Scheduling


� Reduce dragout by increasing drain time; and


� When dripping parts, lift them such that it reduces dragout.


Equipment Layout/Piping/Automation


� Install sliding lids on solvent tanks;


� Increase the freeboard height to significantly reduce solvent evaporation;


� Install automatic parts lift on vapor degreasers;


� Use drain racks to reduce dragout; and


� Drain parts using a rotating rack.


8.3.2 Pollution Prevention for Machining Operations 

Many machining operations use metal-working fluids to cool and lubricate parts 

and machining tools during cutting, drilling, milling, and other machining operations. These 

fluids become contaminated and begin to lose their working characteristics. If neglected, the 

fluids become unusable and require treatment and disposal. Through proper care, the life span of 

the fluids can be extended indefinitely. For most machining operations, prolonging metalworking fluid life reduces the cost of treatment and disposal, as well as the cost of fresh coolant. 

Many MP&M facilities use some type of pollution prevention and water 

conservation practices for machining wastewaters. Some facilities have implemented numerous 

pollution prevention and water conservation methods and technologies that result in very low 

machining wastewater discharge rates and in some cases eliminate the discharge of machining 

fluids. Pollution prevention and water conservation practices are applicable to all machining 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

operations; however, process-related factors and site-specific conditions may restrict the utility of 

certain methods. 

The Agency has identified two categories of pollution prevention and water 

conservation practices and technologies that can be used to reduce metal-working fluid 

discharge: those used to prevent metal-working fluid contamination and those used to extend the 

life of machining fluids, including recovering and recycling metal-working fluids. Within each 

of these categories are several specific practices and technologies. See Appendix D for more 

information on these pollution prevention practices. 

8.3.3 Painting Operations 

Paint is applied to a base material for protective and decorative reasons in various 

forms, including dry powder, solvent-diluted formulations, and water-borne formulations. There 

are various methods of application, the most common being immersion and spraying. Water is 

used in painting operations in paint booth water-wash systems (water curtains), in water-borne 

formulations, in electrophoretic painting solutions and rinses, and in clean-up operations. This 

discussion is directed at water use in spray painting booths; however, Appendix D also provides 

some information on rinsing following electrophoretic painting and water clean-up. 

EPA has identified three categories of pollution prevention and water 

conservation practices that, if implemented, can reduce or eliminate wastewater discharges from 

painting operations: practices to reduce the quantity of paint entering the water system; recycling 

technologies for paint booth water; and conversion of water-wash booths to dry-filter booths. 

These are discussed in this subsection and summarized in Appendix D. It is possible, however, 

that facilities can reduce or eliminate wastewater discharges using different practices than those 

described here. 

8.3.4 Pollution Prevention for Printed Wiring Board Manufacturing 

Printed wiring board manufacturers use a large amount of water each day, mostly 

for rinsing and electroplating processes. The following BMP’s developed specifically for printed 

wiring board manufacturing outline water-saving process changes and controls that can be 

inexpensively incorporated in the production process. A number of these pollution prevention 

processes are described in more detail in Section 8.1. 

� Use dry film photoresist instead of wet applications. 

� Examine the pre-plating rinse processes: 

- Based on monitoring data, eliminate unnecessary cycles and rinse 

only until desired cleanliness is reached. 

- Switch from continuous to on-demand rinsing, and from oncethrough to closed-loop use. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

- Use counter-current rinsing. 

- Use air or workpiece agitation to increase rinsing efficiency. 

- Spray rinse with high-pressure, low flow nozzles. This can reduce 

rinse water use up to 60 percent. 

- Link flow controls to conductivity meters that measure the total 

dissolved solids in the rinses. 

� Examine the electroplating process. Extending bath life will reduce both 

water consumption and toxics in the effluent. 

- Reduce drag-in through efficient rinsing. 

- Use deionized or distilled water for makeup. 

- Reduce drag-out through the following methods: 

a) 

b) 

c) 

Minimize bath chemical concentrations. 

Use nonionic wetting agents to reduce surface tension in 

the process baths. 

Prior to rinsing, maximize water returned to the process 

bath through several measures – withdraw pieces from the 

baths slowly, install drainage boards between process baths 

and rinses to return drag-out back to the process bath, 

install rails above process baths to hang workpiece/racks 

for drainage and/or use air knives or spray rinses above 

process baths to rinse excess solution into the process bath. 

- Restore barrel holes. 

- Maintain bath solution quality through monitoring, replacement of 

reagents and stabilizers, and impurity removal. 

� Install multiple baths after the process bath for using counter-current 

rinsing wherever possible. 

8.4 Preliminary Treatment of Segregated Wastewater Streams 

Preliminary treatment systems reduce pollutant loadings in segregated waste 

streams prior to combined end-of-pipe treatment. Wastewater containing pollutants such as 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

cyanide, hexavalent chromium, oil and grease, or chelated metals may not be treated effectively 

by chemical precipitation and gravity settling without preliminary treatment. Proper segregation 

and treatment of these streams is critical for the successful treatment of process wastewater. 

Highly concentrated metal-bearing wastewater also may require pretreatment to reduce metal 

concentrations before end-of-pipe treatment. This subsection describes the following wastewater 

streams that typically undergo preliminary treatment at MP&M facilities: 

� Chromium-bearing wastewater; 

� Concentrated metal-bearing wastewater; 

� Cyanide-bearing wastewater; 

� Chelated metal-bearing wastewater; and 

� Oil-bearing wastewater. 

Table 8-3 summarizes these preliminary treatment operations. 

8.4.1 Chromium-Bearing Wastewater 

MP&M facilities generate hexavalent-chromium-bearing wastewater from acid 

treatment, anodizing, conversion coating, and electroplating operations and rinses. Hexavalent 

chromium exists in an ionic form and does not form a metal hydroxide; therefore, hexavalent 

chromium cannot be treated by chemical precipitation and sedimentation (discussed in Section 

8.5.1). The wastewater requires preliminary chemical treatment to reduce the hexavalent 

chromium to trivalent chromium, which can be removed by chemical precipitation and 

sedimentation. As shown in Table 8-3, EPA estimates there are over 1,800 MP&M facilities that 

perform hexavalent chromium reduction. The chemical reduction process is discussed below. 

Figure 8-7 presents a diagram of a continuous chromium reduction system. 

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8.0 - Pollution Prevention and Wa

Table 8-3


MP&M Preliminary and End-of-Pipe Treatment Technologies


8-32


Technology Technology Description 

Demonstration 

Number of 

Facilities Visited 

Using the 

Technology a 

Number of 

Survey 

Facilities Usi

the Technolog

Chemical Emulsion Breaking Followed by Gravity Oil/Water 

Separation 

Adds acids (typically sulfuric), polymer, and sometimes alum to oilbearing wastewater to break oil/water emulsions for subsequent gravity 

separation. Separated oil is skimmed and hauled by a contractor. A 

facility may purchase the recycled oil for reuse. 

13 56 

Chemical Emulsion Breaking Followed by Dissolved Air Flotation 

Adds acids (typically sulfuric), polymer, and sometimes alum to oilbearing wastewater to break oil/water emulsions for subsequent gravity 

separation. Introduces gas bubbles into the wastewater, bringing oils and 

solids to the surface for subsequent removal. 

85 25 

Chemical Reduction of Hexavalent Chromium 

Reduces hexavalent chromium to trivalent chromium using a reducing agent such as sulfur dioxide, sodium bisulfite, or sodium metabisulfite. 

56 103 

Cyanide Destruction by 

Alkaline Chlorination 

Destroys cyanide by adding chlorine (usually sodium hypochlorite or 

chlorine gas) to high pH wastewater to first oxidize cyanide to cyanate, 

then cyanate to carbon dioxide and nitrogen gas. 

14 53 

Oil Skimming of Oily 

Wastewater Streams 

Removes free floating oil by gravity separation and mechanical 

skimming. This technology does not remove emulsified oils. 

45 89 

Cyanide Oxidation by Ozone Ozone oxidizes cyanide to ammonia, carbon dioxide and oxygen. 0 1 Chelation Breaking/ Precipitation to Remove Complexed Metals 

Wastewater from electroless plating and some cleaning operations 

contains chelated metals that cannot be removed by chemical 

precipitation. Strong reducing agents such as dithiocarbamate are added 

to break the metal-organic chelate bond and precipitate the metal. 

15 49 

Ultrafiltration Removes emulsified or free-floating oils. This technology also removes 

other solids. Uses a membrane of very small pore size. 

19 23 

Activated Carbon Adsorption Removes dissolved organic pollutants by filtration through and 

adsorption on activated carbon. This technology requires preliminary 

treatment to remove suspended solids and oil and grease. 

9 21 

Aerobic Biological Treatment Biochemically decomposes organic materials in the presence of oxygen 

using microorganisms. 

1 

(used to treat 

nonprocess 

wastewater) 

4 

Air Stripping Removes dissolved volatile organic pollutants by contacting the organics 

in the wastewater with a continuous stream of air bubbles. Volatile 

organic pollutants are transferred from the wastewater to the air. 

0 2 
8.0 - Pollution Prevention and Wa

Table 8-3 (Continued)


8-33


Technology Technology Description 

Demonstration 

Number of 

Facilities Visited 

Using the 

Technology a 

Number of 

Survey 

Facilities Usi

the Technolog

Neutralization Neutralizes high or low pH wastewater to within an acceptable range 

using acidic or alkaline chemicals. Common acids include sulfuric and 

hydrochloric. Common alkaline chemicals include lime and sodium 

hydroxide. 

63 233 

Chemical Precipitation and 

Gravity Sedimentation 

Removes metals by precipitating insoluble compounds such as 

hydroxides, sulfides, or carbonates. Precipitation as metal hydroxides 

using lime or sodium hydroxide is the most common. Precipitated and 

flocculated solids are removed by gravity sedimentation in a clarifier. 

149 203 

Chemical Precipitation and 

Microfiltration 

Removes metals by precipitating insoluble compounds such as 

hydroxides, sulfides, or carbonates. Precipitation as metal hydroxides 

using lime or sodium hydroxide is the most common. Precipitated and 

flocculated solids are removed by microfiltration through a porous 

membrane. 

6 5 

Atmospheric Evaporation Includes both natural solar evaporation and forced atmospheric 

evaporation by which the evaporation rate is accelerated by increased 

temperature, air flow, and surface area. 

4 12 

Ion Exchange (end-of-pipe) Polishing technique after metals precipitation to scavenge low 

concentrations of residual metals (cations) using combined cation and 

anion exchange. Anions remain in solution and are discharged. 

Concentrated metal-containing regenerants are typically returned to the 

metals precipitation system. 

17 39 

Multimedia Filtration Removes solids from wastewater using filter media of different grain 

size. Coarser media remove larger particles and finer media remove 

smaller particles. Media include garnet, sand, and anthracite coal. The 

filter is periodically backwashed to remove solids. 

12 16 

Sand Filtration Removes solids from wastewater using a sand filter. The filter is 

periodically backwashed to remove solids. 

46 41 

Gravity Settling Physically removes suspended particles by gravity. This technology does 

not include the addition of any chemicals. 

7 46 

Centrifugation of Sludge Separates water from solids using centrifugal force. Centrifugation 

dewaters sludges, reducing the volume and creating a semisolid cake. 

Centrifugation of sludge can typically achieve a sludge of 20-35 percent 

solids. 

7 9 

Gravity Thickening of Sludge Physically separates solids and water by gravity. Gravity thickening can 

typically thicken sludge to 5 percent solids. 

83 85 
8.0 - Pollution Prevention and Wa

Table 8-3 (Continued)


Technology Technology Description 

Demonstration 

Number of 

Facilities Visited 

Using the 

Technology a 

Number of 

Survey 

Facilities Usi

the Technolog

Pressure Filtration of Sludge Physically separates solids and water by pressure filtration. Most 

commonly performed in a plate-and-frame filter press where the sludge 

builds up between the filter plates and water is filtered through a cloth. Pressure filtration can produce a sludge cake with greater than 40 percent 

solids. 

140 189 

Sludge Drying Dries sludge by heating, which causes the water in the sludge to 

evaporate. 

28 48 

Vacuum Filtration of Sludge Physically separates solids and water by vacuum filtration. Most 

commonly performed in a cylindrical drum vacuum filter, where water is 

pulled by vacuum through the filter and dewatered sludge is retained and 

subsequently scraped from the filter surface. Vacuum filtration can 

produce a sludge cake with 20 - 30 percent solids. 

11 9 

8-34


Source: MP&M site visits, MP&M sampling episodes, MP&M surveys and technical literature. Statistics specific to wastewater-discharging facilitiesaIndicates the number of MP&M facilities visited by EPA using the listed technology. EPA visited a total of 221 facilities.
bIndicates the number of water-discharging survey facilities that reported using this technology. Based on 874 MP&M survey respondents for the 199

1989 survey.


cIndicates the estimated number of MP&M facilities currently performing this technology based on the 1989 and 1996 detailed surveys. EPA’s nation

detailed survey and the 1989 survey includes approximately 44,000 water-discharging facilities. EPA estimated numbers in this column using statistic

MP&M survey respondents. See Section 3.0 for a discussion of the development of national estimates and statistical survey weights.

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Figure 8-7. Chemical Reduction of Hexavalent Chrome 

Reduction is a chemical reaction in which electrons are transferred from one 

chemical (the reducing agent) to the chemical being reduced. Sulfur dioxide, sodium bisulfite, 

sodium metabisulfite, peroxide, and ferrous sulfate form strong reducing agents in water. 

MP&M facilities use these agents to reduce hexavalent chromium to the trivalent form, which 

allows the metal to be removed from solution by subsequent chemical precipitation. 

Sodium metabisulfite, sodium bisulfite, and sulfur dioxide are the most widely 

used reducing agents at MP&M facilities (14). Below is an equation showing the sulfur dioxide 

reaction (reduction using other reagents is similar chemically): 

(8-2) 

An operating pH of between 2 and 3 is normal for chromium reduction. At pH 

levels above 5, the reduction rate is slow, and oxidizing agents such as dissolved oxygen and 

ferric iron interfere with the reduction process by consuming the reducing agent. 

Typically, the chemicals are retained in a reaction tank for 45 minutes. The tank 

is equipped with pH and oxidation-reduction potential (ORP) controls. Sulfuric acid is added to 

maintain a pH of approximately 2, and a reducing agent is metered to the reaction tank to 

maintain the target ORP. 

Chemical reduction of hexavalent chromium is a proven technology that is widely 

used at MP&M facilities. Operation at ambient conditions requires little energy, and the process 

8-35

8.0 - Pollution Prevention and Wastewater Treatment Technologies 

is well suited to automatic control. For high concentrations of chromium, treatment chemical 

costs may be significant. 

Maintenance of chemical reduction systems consists of sludge removal, the 

frequency of which depends on the concentration of contaminants. There also may be small 

amounts of sludge generated due to minor shifts in the solubility of the contaminants (e.g., iron 

hydroxides). This sludge can be removed by the sludge-handling equipment associated with 

subsequent end-of-pipe chemical precipitation and sedimentation. 

8.4.2 Concentrated Metal-Bearing Wastewater 

Facilities use several methods to manage concentrated metal-bearing wastewater 

from spent process solutions. Facilities may: 

� Meter the concentrated metal-bearing wastewater slowly to the end-of-pipe 

chemical precipitation system and commingle it with other facility 

wastewater; 

� Treat the concentrated metal-bearing wastewater in a batch pretreatment 

system; or 

� Send concentrated metal-bearing wastewater for off-site treatment. 

Batch pretreatment allows better control of the treatment system (e.g., the 

treatment chemicals can be better tailored to the specific solution being treated), better treatment 

of difficult-to-treat materials (e.g., photo-resist-bearing wastewater), and potential recovery of 

metals from the sludge. With batch treatment, facilities typically discharge effluent from the 

batch treatment tank to the end-of-pipe treatment system for additional polishing. 

Batch chemical precipitation of concentrated metal-bearing wastewater typically 

occurs in a single stirred tank, where a precipitating agent (e.g., sodium hydroxide, lime, sodium 

sulfide) is added to create an insoluble metal hydroxide or sulfide complex. Following 

precipitate formation, a polyelectrolyte is added to flocculate the metal hydroxide or metal 

sulfide particles into larger clumps that will settle to the bottom of the reaction tank following 

mixing. Clarified effluent from the batch tank is discharged to the end-of-pipe treatment system 

and the settled sludge, typically containing only one type of metal, is transferred off-site for 

metals recovery. 

8.4.3 Cyanide-Bearing Wastewater 

Plating and cleaning wastewater may contain significant amounts of cyanide, 

which should be removed through preliminary treatment. In addition to its toxicity, cyanide 

forms complexes with metals that prohibit subsequent removal in chemical precipitation systems. 

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8-37

Figure 8-8. ide Destruction Through Alkaline Chlorination

Cyanide typically is treated using alkaline chlorination with sodium hypochlorite or chlorine gas

or by ozone oxidation. o processes are described below.

8.4.3.1 Alkaline Chlorination

Alkaline chlorination is in wide use in industrial wastewater treatment to destroy

cyanide. MP&M facilities using alkaline chlorination to

remove cyanide. pically used as either chlorine gas or sodium hypochlorite (i.e.,

bleach). idizes cyanides to carbon dioxide and nitrogen by

the following two-step chemical reaction (10):

(8-3)

(8-4)

Figure 8-8 presents a diagram of an alkaline chlorination system.

Treatment equipment often consists of an equalization tank followed by two

continuous reaction tanks, although the batch reaction can occur in a single tank. 

an electronic controller to monitor and maintain the required pH and ORP. idize cyanides

to cyanates, chlorine or sodium hypochlorite is metered to the first reaction tank as necessary to

maintain the ORP at 350 to 400 millivolts, and aqueous sodium hydroxide is added to maintain a

pH of approximately 11. that most of the cyanide exists in the CN- form, rather

than as the highly toxic hydrogen cyanide (HCN) form. n the second reaction tank, the ORP and

the pH level typically are maintained at 600 millivolts and 8 to 9, respectively, to oxidize cyanate

to carbon dioxide and nitrogen. tank has a chemical mixer designed to provide

approximately one turnover per minute. 

The batch process typically occurs in two tanks, one to collect water over a

specified time period and one to treat an accumulated batch. f concentrated wastes are

Cyan

These tw

Table 8-3 shows there are over 1,100 

Chlorine is ty

The alkaline chlorination process ox

Each tank has

To ox

This pH dictates 

I

Each reaction 

I
8.0 - Pollution Prevention and Wastewater Treatment Technologies 

frequently dumped, another tank may be required to equalize the flow to the treatment tank. 

When the holding tank is full, the liquid is transferred to the reaction tank for treatment. 

Alkaline chlorination can take place at ambient temperature, can be automatically 

controlled at relatively low cost, and can achieve effluent concentrations of free cyanide that are 

below the detection limit. Disadvantages include the need for careful pH control, possible 

chemical interference in treating mixed wastes, and the potential hazard of storing and handling 

chlorine gas (if sodium hypochlorite is not used). If organic compounds are present, chlorinated 

organic compounds may be generated. Additionally, there are several safety concerns associated 

with handling chlorine gas and with the gas feed system. This technology is not effective in 

treating metallocyanide complexes, such as ferrocyanide. 

8.4.3.2 Ozone Oxidation 

A less common cyanide treatment method is ozone oxidation. Ozone, generated 

as a gas, is bubbled through a wastewater solution containing free cyanide. The ozone reacts 

with cyanide, converting it to cyanate. Additional ozone reacts with the cyanate to convert it to 

nitrogen gas, ammonia, and bicarbonate, as shown by the reactions below. 

CN- + O3 -------> CNO- + O2 (8-5) 

3CNO-+ 2O3 + 2OH- + 2H2O -----------> 3HCO3

-

+ NH3 + N2 + 2O2 (8-6) 

The reaction rate is limited by mass transfer of ozone to the solution, the cyanide 

concentration, and temperature. Literature data show that oxidation can reduce amenable 

cyanide in electroplating wastewaters to below detection (5). Ozone is not effective in treating 

metallocyanide complexes, such as ferrocyanide, unless ultraviolet light is added to the reaction 

tank (6). 

One advantage ozone has over chlorine is the type of residuals formed. Chlorine 

oxidation of organic compounds has the potential to form trihalomethanes. Ozone oxidizes 

organic compounds to form relatively less toxic, short-chain organic acids, ketones, and 

aldehydes. Equipment required for ozone oxidation of cyanides includes an ozone generator, gas 

diffusion system, a mixed reaction tank, and off-gas controls to prevent the release of unreacted 

ozone. 

The major disadvantage of the ozone oxidation process is the capital and 

operating cost (12). Ozone must be manufactured on-site and delivered directly to the reaction 

tank. Ozone generation equipment is expensive, and facilities also must purchase closed reaction 

tanks and ozone off-gas treatment equipment. 

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8.4.4 Chelated-Metal-Bearing Wastewater 

Certain process wastewaters evaluated for the final rule contain chelating agents 

that form metal complexes and interfere with conventional chemical precipitation treatment. 

This wastewater is often associated with electroless plating and requires specific treatment for the 

chelated metals. In general, there are three methods of treating these wastewaters: 

� Reduction to elemental metal; 

� Precipitation as an insoluble compound; and 

� Physical separation. 

8.4.4.1 Reduction to Elemental Metal 

Reduction to elemental metal can be done using one of two methods. One method 

is electrolytic recovery (see Section 8.2.6), in which the dissolved metal is deposited on a cathode 

for reclamation or disposal. The electric current provides the electrons to reduce the metal ion to 

its elemental form. The reaction rate and achievable concentration for this technology depend on 

the volume of wastewater per unit surface area of cathode. This method typically does not lower 

metal concentrations to levels sufficient for wastewater discharge. 

The second method uses a reducing agent to provide the electrons to reduce the 

metal. Possible reducing agents for treating chelated wastewater streams include: 

� Dithiocarbamate (DTC); 

� Sodium borohydride; 

� Hydrazine; and 

� Sodium hydrosulfite. 

Upon reduction, the metal forms a particulate in solution, which a solids removal technique, such 

as gravity clarification, can remove. For effective use, these reducing agents sometimes require 

the use of other chemicals (e.g., lime or sodium hydroxide) for pH adjustment. Figure 8-9 

presents a diagram showing this method of chemical reduction of chelated metals. 

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Figure 8-9. Chemical Reduction / Precipitation of Chelated Metals 

8.4.4.2 Precipitation as an Insoluble Compound 

Chelating agents hinder the formation of hydroxides, making hydroxide 

precipitation ineffective for treating chelated-metal-bearing wastewaters. Other precipitation 

methods that are less affected by chelating agents include sulfide precipitation, DTC 

precipitation, and carbonate precipitation. Section 8.5.1 discusses sulfide precipitation and 

carbonate precipitation. 

DTC is added to solution in stoichiometric ratio to the metals present. Equation 

8-7 shows the reduction of nickel using DTC: 

Ni2+

(aq) + DTC2-(aq) � Ni0

(s) (8-7) 

DTC is effective in treating wastewater containing chelated metals. Based on information 

provided in the MP&M Detailed Surveys, approximately 53 percent of MP&M facilities with 

chelated metals use DTC for treatment. DTC compounds are a class of pesticides and, if used 

incorrectly, may cause process upsets in the biological treatment system used at the POTW and 

can potentially be harmful to the environment (e.g., lead to fish kills if it passes through the 

POTW and reaches surface waters). Another disadvantage is that DTC precipitation generates 

large amounts of sludge. 

Other treatment chemicals used by MP&M industries for treatment of chelated 

metals include: 

� Borohydride; 

� Sodium hydrosulfite; 

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� Sodium metabisulfite; 

� Polysulfide polymer; 

� Sodium hydroxide; 

� Ferrous sulfate; 

� Ferris chloride; and 

� Formaldehyde. 

EPA evaluated the treatment performance of polysulfide polymer (Sampling 

Episode 6462) and determined this compound effectively treated chelated copper and nickel to 

metal finishing effluent limits (40 CFR 433). Further concentration reductions may have been 

achievable if additional jar testing was conducted. Iron or calcium salts and pH adjustment may 

also provide acceptable methods for chelated metals treatment; however, no data are available for 

evaluation. 

The Orange County Sanitation District (OCSD) compile a study of a NDMA and 

found that the highest concentrations of a probable human carcinogen, n-nitrosodimethylamine 

(NDMA), at a printed circuit board manufacturer were observed at effluent from batch treatment 

(18). “Overdosing” of DTC in batch treatment systems may be common and may lead to the 

formation of NDMA. During its evaluation OCSD encouraged facilities and treatment chemical 

vendors to develop non-NDMA forming treatments. EPA compiled information on DTC 

alternative treatments for the record (see “DTC Alternatives for Treatment of Chelated Metals,” 

Section 24.6.1 of the rulemaking record, DCN 17962). 

8.4.4.3 Physical Separation 

Ion exchange and reverse osmosis can separate metals from solution. These 

technologies are not affected by chelating agents in the wastewater, making them effective in 

treating wastewater from electroless plating. Sections 8.2.8.1 and 8.2.8.2, respectively, discuss 

these technologies. 

8.4.5 Oil-Bearing Wastewater 

Some MP&M wastewater (e.g., alkaline cleaning wastewater and water-based 

metal-working fluids) contains significant amounts of oil and grease. This wastewater 

sometimes requires preliminary treatment to remove oil and grease and organic pollutants. 

Oil/water separation includes breaking oil/water emulsions (oil dispersed in water, stabilized by 

electrical charges and emulsifying agents) as well as gravity separation of oil. When only free oil 

(i.e., nonemulsified oil) is present, oil skimming is enough for effective treatment. Techniques 

available to remove oil include chemical emulsion breaking followed by oil/water separation or 

dissolved air flotation (DAF), oil skimming, and ultrafiltration. These technologies are described 

in more detail below. 

Oil/water separation not only removes oil but also removes organic compounds 

that are more soluble in oil than in water. Subsequent clarification removes organic solids 

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directly and may also remove dissolved organic compounds by adsorption on inorganic solids. In 

MP&M operations, sources of these organic compounds mainly are process coolants and 

lubricants, additives to formulations of cleaners, paint formulations, or leaching from plastic 

lines and other materials. 

8.4.5.1 Chemical Emulsion Breaking 

Chemical emulsion breaking is used to break stable oil/water emulsions. A stable 

emulsion will not separate or break down without chemical and or physical treatment. Chemical 

emulsion breaking is applicable to wastewater containing emulsified coolants and lubricants such 

as machining and grinding coolants and impact and pressure deformation lubricants. This 

technology also is applicable to cleaning solutions that contain emulsified oils. Figure 8-10 

shows a diagram of a type of continuous chemical emulsion breaking system. 

Figure 8-10. Continuous Chemical Emulsion Breaking Unit with Coalescing Plates 

Treatment of spent oil/water emulsions involves adding chemicals to break the 

emulsion followed by oil/water separation. The major equipment required for chemical emulsion 

breaking includes reaction chambers with agitators, chemical storage tanks, chemical feed 

systems, pumps, and piping. Factors to be considered for breaking emulsions are type of 

chemicals, dosage and sequence of addition, pH, mixing, heating requirements, and retention 

time. 

Chemicals (e.g., polymers, alum, ferric chloride, and organic emulsion breakers) 

break emulsions and allow coagulation (13) by neutralizing repulsive charges between particles, 

precipitating or salting out emulsifying agents, or weakening the interfacial film between the oil 

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and water so it is readily broken. Reactive cations (e.g., H+, Al+3, Fe+3) and cationic polymers are 

particularly effective in breaking dilute oil/water emulsions. Once the charges are neutralized or 

the interfacial film broken, the small oil droplets and suspended solids either adsorb on the 

surface of the floc that is formed, or break out and float to the top. Different types of 

emulsion-breaking chemicals are used for different types of oils. If more than one chemical is 

required, the sequence of adding the chemicals can affect both breaking efficiency and chemical 

dosages. 

Another important consideration in emulsion breaking is pH, especially if cationic 

inorganic chemicals, such as alum, serve as coagulants. For example, a pH of between 2 and 4 

keeps the aluminum ion in its most positive state where it most effectively neutralizes charges. 

After some of the oil is broken free and skimmed, raising the pH into the 6-to-8 range with lime 

or caustic causes the aluminum to hydrolyze and precipitate as aluminum hydroxide. This floc 

entraps or adsorbs destabilized oil droplets, which can then be separated from the water. 

Cationic polymers can break emulsions over a wider pH range and thus avoid acid corrosion and 

the additional sludge generated from neutralization; however, this process usually requires 

adding an inorganic flocculent to supplement the adsorptive properties of the polymer emulsion 

breaker. 

Mixing is important in effectively breaking oil/water emulsions because it 

provides proper chemical feed and dispersion. Mixing also causes droplets to collide and break 

the emulsion and promotes subsequent agglomeration into larger droplets. Heating also 

improves chemical emulsion breaking by lowering the viscosity and increasing the apparent 

specific gravity differential between oil and water. In addition, heating increases the frequency 

of droplet collisions, which helps to rupture the interfacial film. 

Once an emulsion is broken, the oil floats to the surface of the water because of 

the difference in specific gravity between oil and water. Solids usually form a layer between the 

oil and water because some solids become suspended in the oil. The longer the retention time, 

the more complete the separation between the oil, solids, and water. Oils and solids typically are 

skimmed from the surface of the water after chemical emulsion breaking. Often, other 

techniques such as air flotation or rotational separation (e.g., centrifugation) enhance separation 

after chemical emulsion breaking. 

The advantages of chemical emulsion breaking are the high removal efficiency 

potential and the possibility of reclaiming the oily waste. Disadvantages include corrosion 

problems associated with acid-alum systems, operator training requirements for batch treatment, 

chemical sludges produced, and poor efficiency for low oil concentrations. 

Chemical emulsion breaking is a very reliable process. The main control 

parameters are pH and temperature. Some MP&M facilities may achieve effective emulsion 

breaking by lowering the pH with acid, by heating the wastewater, or both. Maintenance is 

required on pumps, mixers, instrumentation and valves, as is periodic cleaning of the treatment 

tank to remove any accumulated solids. Energy use typically is limited to mixers and pumps, but 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

also can include heating. Solid wastes generated by chemical emulsion breaking include surface 

oil and oily sludge, which are usually contract hauled for disposal by a licensed contractor. If the 

recovered oil contains a low enough percentage of water, it may be burned for its fuel value or 

processed and reused. 

8.4.5.2 Oil Skimming 

Oil skimming is a physical separation technology that removes free or floating oil 

from wastewater using the difference in specific gravity between oil and water. Common 

separation devices include belts, rotating drums, disks, and weir oil skimmers and coalescers. 

These devices are not suited to remove emulsified oil, which requires chemical treatment, 

ultrafiltration, or other treatment. Figures 8-11a and 8-11b show diagrams of disk and belt oil 

skimming units, respectively, that are applicable for small systems or on process tanks. The oil 

removal system shown in Figure 8-10 is a coalescing separator used for large systems. 

Figure 8-11a. Disk 

Oil Skimming Unit 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Figure 8-11b. 


Belt Oil Skimming Unit 


To separate oil from process solutions, oil skimming devices typically mount onto 

the side of a tank and operate on a continuous basis. The disk skimmer is a vertically rotating 

disk that is partially submerged in the solution (see Figure 8-11a). The disk continuously 

revolves between spring-loaded wiper blades that are located above the liquid surface. The 

disk’s adhesive characteristics cause the floating oil to remain on the disk. As the disk’s surface 

passes under the wiper blades, the blades scrape off the oil, which is diverted to a run-off spout 

for collection. Belt and drum skimmers operate in a similar manner, with either a continuous belt 

or drum rotating partially submerged in a tank. As the surface of the belt or drum emerges from 

the liquid, the oil that adheres to the surface is scraped off (drum) or squeezed off (belt) and 

diverted to a collection vessel. The oil typically is hauled off-site for disposal. 

Gravity separators use overflow and underflow weirs to skim a floating oil layer 

from the surface of the wastewater. The oil layer flows over the weir into a trough for disposal or 

reuse while most of the water flows underneath the weir. A diffusion device, such as a vertical 

slot weir, helps create a uniform flow through the system and increase oil removal efficiency. 

An oil skimmer’s removal efficiency depends on the composition of the waste 

stream and the retention time of the water in the tank. Larger, more buoyant particles require less 

retention time than do smaller particles. The retention time necessary for phase separation and 

subsequent skimming varies from 1 to 15 minutes, depending on the wastewater characteristics. 

Gravity-type separators tend to be more effective for wastewater streams with consistently large 

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amounts of surface oil. Drum and belt type skimmers are more applicable to waste streams 

containing smaller amounts of floating oil. A gravity separator in conjunction with a drum-type 

skimmer effectively removes floating contaminants from nonemulsified oily waste streams. 

Coalescers remove oil droplets too finely dispersed for conventional gravity 

separation-skimming technology. Coalescing also reduces the residence times (and therefore 

separator sizes) required to separate oil from some wastes. The basic principle of coalescence 

involves the attraction of oil droplets to the coalescing medium (typically plates). The oil 

droplets accumulate on the medium and then rise to the surface of the solution as they combine to 

form larger particles. The most important requirements for coalescing media are attraction for oil 

and large surface area. Coalescing media include polypropylene, ceramic, and glass. 

Coalescing stages may be integrated with a wide variety of gravity oil separators, 

and some systems may incorporate several coalescing stages. A preliminary oil skimming step 

avoids overloading the coalescer. 

8.4.5.3 Flotation of Oils or Solids 

Air flotation combined with chemical emulsion breaking is an effective way to 

treat oily wastewater containing low concentrations of metals. Flotation separates oil and grease 

from the wastewater, and entrainment or adsorption will remove small amounts of metal. In 

DAF, air is injected into a fluid under pressure. The amount of air that can dissolve in a fluid 

increases with increasing pressure. When the pressure is released, the air comes out of solution 

as bubbles, which attach to oil and grease molecules and “float” the oil and grease to the surface. 

Induced-air flotation uses the same separation principles as DAF systems but the gas is selfinduced by a rotor-disperser mechanism. 

Figure 8-12 shows a diagram of a DAF unit. A DAF system consists of a 

pressurizing pump, air injection equipment, pressurizing tank, a pressure release valve, and a 

flotation tank. DAF systems operate in two modes: full-flow pressurization and recycle 

pressurization. In full-flow pressurization, all influent wastewater is pressurized and injected 

with air. The wastewater then enters the flotation unit where the pressure is relieved and bubbles 

form, causing the oil and grease to rise to the surface with the air bubbles. In recycle 

pressurization, part of the clarified effluent is recycled back to the influent of the DAF unit, then 

pressurized and supersaturated with air. The recycled effluent then flows through a pressure 

release valve into the flotation unit. Pressurizing only the recycle reduces the amount of energy 

required to pressurize the entire influent. DAF is the most common method of air flotation. 

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Figure 8-12. Dissolved Air Flotation Unit 

8.4.5.4 Ultrafiltration 

Ultrafiltration is a membrane-based process used to separate solution components 

based on molecular size and shape. Under pressure, solvent and small solute species pass 

through the membrane and are collected as permeate while the membrane retains larger 

compounds, which are recovered as concentrate. Figure 8-5 shows a typical membrane filtration 

unit. 

Ultrafiltration typically removes materials ranging from 0.002 to 0.2 microns or 

molecular-weights from 500 to 300,000. It can be used to treat oily wastewater. Filtering the 

ultrafiltration influent removes large particles and free oil to prevent membrane damage and 

fouling. Most ultrafiltration membranes consist of homogeneous polymer or copolymer material. 

The transmembrane pressure required for ultrafiltration depends on membrane pore size, and 

typically ranges between 15 to 200 psi. 

Ultrafiltration typically produces a concentrated oil phase that is two to five 

percent of the influent volume. Oily concentrates typically are hauled off-site or incinerated, and 

the permeate (water phase) can be either treated further to remove water-soluble metals and 

organic compounds or discharged, depending on local and state requirements. 

An ultrafiltration system includes: pumps and feed vessels, piping or tubing, 

monitoring and control units for temperature, pressure, and flow rate; process and cleaning tanks; 

and membranes. Membranes are designed specifically to handle various waste stream 

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parameters, including temperature, pH, and chemical compatibility. There are different types of 

membranes, including hollow fiber, tubular, flat plate, and spiral wound. The type selected 

depends on the application. For example, tubular membranes commonly separate suspended 

solids, whereas spiral wound membranes separate oil from water. Ultrafiltration systems 

designed to remove oil typically are more expensive than are DAF systems. Membranes must be 

cleaned periodically to ensure effective treatment. 

End-of-Pipe Wastewater Treatment and Sludge-Handling Technologies 

This subsection describes end-of-pipe technologies that MP&M facilities use for 

wastewater treatment and sludge handling. Table 8-3 describes each technology and lists the 

number of MP&M facilities that use the technology. Section 8.5.1 discusses metal removal by 

chemical precipitation, Section 8.5.2 discusses oil removal technologies, Section 8.5.3 discusses 

wastewater polishing technologies, and Section 8.5.4 discusses sludge-handling technologies. 

8.5.1 Chemical Precipitation for Metals Removal 

The most common end-of-pipe treatment technology used at MP&M facilities to 

remove dissolved metals is chemical precipitation and flocculation followed by gravity 

clarification. The data in Table 8-3 show there are nearly 3,000 MP&M facilities that use 

chemical precipitation and gravity settling to treat their metals-bearing wastewater. Some 

MP&M facilities use microfiltration, filter press operations, centrifuge operations, DAF, and 

American Petroleum Institute (API) separation in place of clarification, but this subsection 

discusses only clarification and microfiltration. The types of equipment used for chemical 

precipitation vary widely. Small batch operations can take place in a single tank that typically 

has a conical bottom to permit removal of settled solids. Continuous processes usually occur in a 

series of tanks, including an equalization tank, a rapid-mix tank for dispersing the precipitating 

chemicals, and a slow-mix tank for adding coagulants and flocculants and for floc formation. 

For continuous-flow systems, the first tank in the treatment train typically is the 

equalization tank. The flow equalization tank prevents upsets in processing operations from 

exceeding the hydraulic design capacity of the treatment system, improves chemical feed control, 

and allows wastewater neutralization. 

Commingled wastewater from the equalization tank enters the rapid mix tank, 

along with various types of precipitation chemicals added to convert the soluble metals into 

insoluble compounds. Following precipitation, the wastewater flows into a flocculation tank 

where polyelectrolytes (polymers) are added, causing the precipitated solids to coagulate into 

larger particles that gravity settling or other separation techniques can remove. 

Chemical precipitation is a highly reliable technology when properly monitored 

and controlled. The effectiveness of this technology depends on the types of equipment used and 

numerous operating factors, such as the characteristics of the raw wastewater, types of treatment 

reagents used, and operating pH. In some cases, subtle changes in operating factors (e.g., varying 

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the pH, altering chemical dosage, or extending the process reaction time) may sufficiently 

improve the system’s efficiency. In other cases, modifications to the treatment system are 

necessary. For example, some raw wastewater contains chemicals that may interfere with metals 

precipitation, and may require additional, specialized treatment reagents such as ferrous sulfate, 

sodium hydrosulfate, aluminum sulfate, or calcium chloride. These chemicals may be added 

prior to or during the precipitation process. 

Chemical precipitation systems require routine maintenance for proper operation. 

This includes: calibrating instrumentation and cleaning probes; maintaining chemical pumps and 

mixers (inspection, cleaning, lubrication, replacing seals and packing, replacing check valves, 

cleaning strainers); and monitoring tanks and sumps (inspection, cleaning, corrosion prevention). 

There are several basic methods of performing chemical precipitation and 

flocculation and many variations of each method. The four most common methods are described 

below. Figure 8-13 shows a typical continuous chemical precipitation system. 

Figure 8-13. Continuous Chemical Precipitation System with 

Lamella Clarifier 

Removing precipitated metals typically involves adding flocculating agents or 

polymers to destabilize the hydrodynamic forces that hold the particles in suspension. For a 

continuous treatment system, polymer is either added in-line between the reaction tank and the 

flocculation tank, or in a small rapid mix tank between the reaction tank and flocculation tank. 

In the flocculation tank, the mixer is slowed to promote agglomeration of the particles until their 

density is greater than water and they settle from solution in the clarifier. 

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Hydroxide Precipitation 

Hydroxide precipitation is the most common method of removing metals from 

MP&M wastewater. This process typically consists of several stages. In an initial tank, which is 

mechanically agitated, alkaline treatment reagents such as lime (calcium hydroxide or hydrated 

lime), sodium hydroxide, or magnesium hydroxide are added to the wastewater to precipitate 

metal ions as metal hydroxides. The reaction for precipitation of a divalent metal using sodium 

hydroxide is shown in the following equation: 

(8-8) 

The precipitation process usually operates at a pH of between 8.5 and 11, 

depending on the types of metals in the wastewater. The pH set point for each hydroxide 

precipitation system is determined by jar testing. Jar testing results determine the optimum pH, 

flocculent type and dosage to maximize the removal of target metals. Figure 8-14 shows the 

effect of pH on hydroxide precipitation. Figure 8-14 was developed based on empirical studies 

using single metal solutions in reagent-free water. However, metal solubilities in complex 

wastewater may differ from those shown in the figure, and therefore facilities must test their 

actual wastewater to define the minimum solubility for all metals. 

Iron Coprecipitation 

Iron coprecipitation is one method that has proven effective at reducing the 

concentration of metals such as arsenic, beryllium, cadmium, copper, lead, nickel and zinc to less 

than could be achieved with hydroxide precipitation alone (7). Iron coprecipitation involves 

adding an iron source such as ferric sulfate or ferric chloride to the pH adjustment tank in the 

chemical precipitation treatment system. Iron is then precipitated as iron oxyhydroxide (7). 

During this process, other metal hydroxides (e.g., nickel hydroxide, copper hydroxide) may be 

incorporated as an impurity within the iron oxyhydroxide matrix or physically entrapped within 

its pore spaces. Metal hydroxides may also be adsorbed to the surface of the iron oxyhydroxide 

precipitate. Factors affecting the iron coprecipitation process include iron dose and iron 

oxidation state, pH, the target metals oxidation state, the initial concentration of the target metal, 

and competition for adsorbent sites from other species. Facilities should conduct jar testing 

using their actual wastewater to optimize the operating conditions for this process. 

Sulfide Precipitation 

The sulfide precipitation process uses equipment similar to that used for 

hydroxide precipitation. The major difference between the two processes is the treatment 

reagents used. Sulfide precipitation uses either soluble sulfides (e.g., hydrogen sulfide or sodium 

sulfide) or insoluble sulfides (e.g., ferrous sulfide) in place of alkali reagents used in hydroxide 

precipitation. The sulfide reagents precipitate dissolved metals as metal sulfides, which often 

have lower solubility limits than metal hydroxides. Therefore, the sulfide precipitation process 

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can (for many metals) achieve lower levels of residual dissolved metal in the effluent than 

hydroxide precipitation treatment (see Figure 8-14). The sulfide precipitation reaction is shown 

in the following equation: 

(8-9) 

Figure 8-14. Effect of pH on Hydroxide and Sulfide 

Precipitation (10) 

Unlike hydroxides, sulfide can precipitate most chelated metals and can remove hexavalent 

chromium without first reducing the chromium to its trivalent state. 

The major disadvantages of sulfide precipitation as compared to hydroxide 

precipitation are higher capital and operating costs. Additional disadvantages of sulfide 

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precipitation are the potential for toxic hydrogen sulfide gas generation and excessive sulfide 

releases in the effluent, and the generation of sulfide odors. 

Carbonate Precipitation 

Carbonate precipitation typically uses sodium carbonate (soda ash), sodium 

bicarbonate, or calcium carbonate to form insoluble metal carbonates. The reaction is shown in 

the following equation: 

(8-10) 

Carbonate precipitation is similar in operation to hydroxide precipitation, and its 

purpose is to remove metals such as cadmium or lead. For these metals, carbonate precipitation 

operates at a lower pH to achieve effluent concentrations similar to those achieved by hydroxide 

precipitation. Facilities sometimes operate carbonate precipitation in conjunction with hydroxide 

precipitation, which may improve the overall performance of certain systems. 

Carbonate precipitation is less common than hydroxide precipitation due to the 

higher cost of treatment reagents and certain operational problems, such as the release of carbon 

dioxide, which can result in foaming and floating sludge. Also, because many metal carbonates 

are more soluble than are sulfides or hydroxides, this process does not effectively precipitate all 

target metals. 

Chemical Precipitation Performance Factors 

Ionic strength of the wastewater is another factor that can negatively affect the 

performance of the chemical precipitation system (8). As MP&M facilities lower water usage by 

implementing technologies such as flow restrictors, countercurrent cascade rinsing, and timed 

rinses, the ionic strength of the wastewater reaching the treatment system will increase. In 

process chemistry, a precipitate always forms or dissolves in the presence of indifferent 

electrolytes. Although ions from such species do not participate directly in the solubility 

equilibrium reaction, they do affect the solubility behavior of the precipitate. The following 

chemical equilibrium equations show the impact of ionic strength on the precipitation process: 

CA(s) � C(aq) + A(aq) (8-11) 

The equilibrium constant expression for this reaction is given by 

(Ka)eq = (C)(A) (8-12) 

or 

(Ka)eq = gm[C] gm[A] (8-13) 

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This equation can be rewritten as 

(Ke)eq = (Ka)eq/ (gm)

2 (8-14) 

The greater the concentration of indifferent electrolytes, the greater the ionic 

strength of the solution and the smaller the value of the activity coefficient. In process chemistry, 

the value of g is normally less than 1.0. Therefore, the smaller the value of g, the larger the value 

of (Ke)eq, indicating the solubility of the solid phase (metal hydroxide precipitate) will increase. 

This means that the solubility of a precipitate will increase if the concentration of indifferent 

electrolytes in solution increases (8). MP&M facilities that reduce process water usage should be 

aware of these equilibria changes that will occur within their treatment system. Facilities should 

conduct additional jar testing to determine if they can mitigate the negative impacts with new 

treatment chemistry or add process water to improve treatment efficiency. 

One issue raised during the MP&M public comment period was that treatment 

system performance is fixed (i.e., percent removal) and therefore the effluent concentration is a 

direct function of influent concentration. The MP&M sampling episode data, however, indicate 

the effluent concentration is a function of the minimum solubility of the metal, regardless of the 

influent concentration. As explained in the June 2002 NODA (67 FR 38779), EPA reviewed 

graphical displays of the paired influent and effluent values and other data analyses. Because the 

results were inconclusive and sometimes inconsistent, EPA was unable to reach a conclusion 

about the effect of influent concentrations on the effluent concentrations. If a facility finds that 

influent concentrations appear to affect its effluent concentrations, it may be useful to perform jar 

testing on a representative sample of wastewater to optimize the treatment conditions for both 

high and low influent concentrations. 

After precipitation, the metal hydroxide particles are very fine and resistant to 

settling. To increase their particle size and improve their settling characteristics, coagulating and 

flocculating agents are added, usually in a second tank, and slowly mixed. Coagulating and 

flocculating agents include inorganic chemicals such as alum and ferric sulfate, and a highly 

diverse range of organic polyelectrolytes with varying characteristics suitable for different 

wastewaters. The type and dosage of flocculent and coagulant are based on the results of jar 

testing done using the actual facility wastewater. 

Flocculated particles with densities greater than water settle in a separate 

clarification tank (e.g., a lamella clarifier), under quiescent conditions. Operators remove the 

solids from the bottom of the settling tank or clarifier, then transfer them to a thickener or other 

dewatering process (see Section 8.5.4). Clarifier effluent either undergoes further processing in a 

polishing unit such as a multimedia filter or discharges. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.5.1.1 Gravity Clarification for Solids Removal 

Gravity sedimentation to remove precipitated metal hydroxides is the most 

common method of clarification (solids removal) used by MP&M facilities. Typically, two types 

of sedimentation devices are used: inclined-plate clarifiers (e.g., lamella clarifiers) and circular 

center-feed rim flow clarifiers. 

Lamella clarifiers contain inclined plates oriented at angles varying between 45 

and 60 degrees from horizontal. As the water rises through the clarifier, the solids settle on the 

plates. Clarified effluent continues to the top of the clarifier, passes over a weir, and collects in a 

holding tank. The solids collect on the inclined plates and slide downward and into the bottom 

of the clarifier. When sufficient solids collect in the bottom of the clarifier, they are scraped into 

a sludge hopper and then discharged, usually to a thickener. Figure 8-13 presents a lamella 

clarifier. 

Overflow rates for lamella clarifiers (i.e., between 1,000 and 1,500 gpd/ft2 for 

metal hydroxide sludges) are two to four times higher than the overflow rates for clarifiers not 

equipped with inclined plates. Clarifier inlets must be designed to distribute flow uniformly 

through the tank and plate settlers. In addition, because solids can build up on plate surfaces and 

adversely affect flow distribution, the clarifier should be cleaned periodically. 

Lamella clarifiers are more common at MP&M facilities than other types of 

clarifiers because of the smaller area required. They typically require only 65 to 80 percent of the 

area required for clarifiers without inclined plates. Their design promotes laminar flow through 

the clarifier, even when the water throughput is relatively high. 

In a center-feed rim flow clarifier, wastewater flows into the bottom of a center 

feed well and then up into a circular tank. Heavy particles settle to the bottom of the tank where 

they are raked to a discharge pipe and removed. Materials with a density less than the density of 

water float to the top of the water and are skimmed from the water surface and discharged to a 

scum pit through a scum trough. Scum is removed from the scum pit periodically and then 

disposed of. Clarified effluent flows over the top of the clarifier and is collected in an effluent 

channel and discharged. Figure 8-15 shows a center-feed rim flow clarifier. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Figure 8-15. Center-Feed Rim Flow Clarifier 

8.5.1.2 Microfiltration for Solids Removal 

Microfiltration is an alternative to conventional gravity clarification after chemical 

precipitation. Microfiltration is a membrane-based process used to separate small suspended 

particles based on size and shape. Water and small solute species pass under pressure through a 

membrane and are collected as permeate while larger particles such as precipitated and 

flocculated metal hydroxides are retained by the membrane and are recovered as concentrate. 

Microfiltration is similar to ultrafiltration (Section 8.4.5.4) but has a larger pore size. 

Microfiltration removes materials ranging from 0.1 to 1.0 microns (e.g., colloidal 

particles, heavy metal particulates and their hydroxides). Most microfiltration membranes 

consist of homogeneous polymer material. The transmembrane pressure required for 

microfiltration typically ranges between 3 to 50 psi, depending on membrane pore size. 

Microfiltration produces a concentrated suspended solid slurry that typically goes 

to dewatering equipment such as a sludge thickener or a filter press. The permeate can either be 

treated further to adjust the pH or be discharged, depending on local and state requirements. 

Figure 8-5 shows a typical membrane filtration system. 

The microfiltration system includes: pumps and feed vessels; piping or tubing; 

monitoring and control units for temperature, pressure, and flow rate; process and cleaning tanks; 

and membranes. Membranes are designed specifically to handle various waste stream 

parameters, including temperature, pH, and chemical compatibility. Different types of 

membranes are available, including hollow fiber, tubular, flat plate, and spiral wound. The 

configuration selected for a particular facility depends on the type of application. For example, 

tubular membranes commonly separate suspended solids, whereas spiral wound membranes 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

separate oils from water. Microfiltration is more expensive than conventional gravity 

clarification. Membranes must be cleaned periodically to prevent fouling and ensure effective 

treatment. 

8.5.1.3 Optimization of Existing Chemical Precipitation Treatment System 

Facilities can optimize the performance of an existing chemical precipitation and 

clarification system using a variety of techniques such as adding equalization prior to treatment, 

conducting jar testing to optimize treatment chemistry, upgrading control systems, and providing 

operator training. 

Equalization 

Equalization is simply the damping of flow and concentration variations to 

achieve a constant or nearly constant wastewater treatment system loading (8). Equalization 

improves treatment performance by providing a uniform hydraulic loading to clarification 

equipment, and by damping mass loadings, which improves chemical feed control and process 

reliability. MP&M facilities implement equalization by placing a large collection tank ahead of 

the treatment system. All process water and rinse water entering this tank are mixed 

mechanically and then pumped or allowed to gravity flow to the treatment system at a constant 

rate. The size (volume) of the tank depends on the facility flow variations throughout the day. 

Operating data collected during MP&M sampling episodes indicate hydraulic residence times for 

equalization tanks average 4 to 6 hours. 

Jar Testing 

The purpose of jar testing is to optimize treatment pH, flocculant type and dosage, 

the need for coprecipitants such as iron, and solids removal characteristics. Facilities should 

conduct jar testing on a sample of their actual wastewater to provide reliable information. 

Control System Upgrades 

Typical treatment system controls at MP&M facilities includes pH and ORP 

controllers on alkaline chlorination systems for cyanide destruction, pH controllers on chemical 

precipitation systems, flow and level monitoring equipment on equalization tanks, and solonoid 

valves and metering pumps on chemical feed systems to provide accurate treatment chemical 

dosing. A number of MP&M facilities have computer hardware and software to monitor and 

change treatment system operating parameters. For a number of MP&M facilities, upgrading 

control equipment may reduce both pH and ORP swings caused by excess chemical dosing, 

resulting in consistent effluent metals concentrations. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

Operator Training 

Having operators trained in both the theory and practical application of 

wastewater treatment is key to ensuring the systems are operating at their best. Many MP&M 

facilities send their operators to off-site training centers while others bring consultants familiar 

with their facility’s operations and wastewater treatment system to the facility to train operators. 

Some of the basic elements of an operator training course should include (1): 

� An explanation of the need for wastewater treatment, which emphasizes 

the benefits to employees and the community; 

� An emphasis on management’s commitment to environmental 

stewardship; 

� An explanation of wastewater treatment terminology in simple terms; 

� An overview of the environmental regulations that govern the facility’s 

wastewater discharges; 

� A simple overview of wastewater treatment chemistry; 

� Methods that can optimize treatment performance (e.g., how to conduct jar 

testing); 

� The test methods or parameters used to verify the system is operating 

properly (e.g., control systems); and 

� The importance of equipment maintenance to ensure the system is 

operating at its maximum potential. 

First-time training for new operators may require 4 to 5 days of classroom and 

hands-on study. Experienced MP&M wastewater treatment operators should consider attending 

at least 1 day of refresher training per year to update themselves on the chemistry and to learn 

about new equipment on the market that may help their system’s performance. 

8.5.2 Oil Removal 

Operations such as machining and grinding, disassembly of oily equipment, and 

cleaning can generate wastewater containing organic machining coolants, hydraulic oils, and 

lubricating oils. In addition, shipbuilding facilities may commingle oily bilge water with 

wastewater from other shore-side operations, resulting in a mixed oily wastewater. Information 

collected during MP&M site visits, sampling episodes, and from the MP&M detailed surveys 

showed a variety of methods to treat oily wastewater. The primary treatment technologies are 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

emulsion breaking and gravity flotation, emulsion breaking and DAF, and ultrafiltration. Section 

8.4 discusses these technologies. 

8.5.3 Polishing Technologies 

Polishing systems remove small amounts of pollutants that may remain in the 

effluent after treatment using technologies such as chemical precipitation and gravity 

clarification. These systems also can act as a temporary measure to prevent pollutant discharge 

should the primary solids removal system fail due to a process upset or catastrophic event. The 

following are descriptions of end-of-pipe polishing technologies that are applicable to MP&M 

facilities. 

8.5.3.1 Multimedia Filtration 

Sand filtration and multimedia filtration systems typically remove small amounts 

of suspended solids (metal precipitates) entrained in effluent from gravity clarifiers. Sand and 

multimedia polishing filters usually are designed to remove 90 percent or greater of all filterable 

suspended solids 20 microns or larger at a maximum influent concentration of 40 mg/L. 

Wastewater is pumped from a holding tank through the filter. The principal design factor for the 

filter is the hydraulic loading. Typical hydraulic loadings range between 4 and 5 gpm/ft2

 (9). 

Sand and multimedia filters are cleaned by backwashing with clean water. Backwashing is timed 

to prevent breakthrough of the suspended solids into the effluent. Figure 8-16 shows a diagram 

of a multimedia filtration system. 

Figure 8-16. Multimedia Filtration System 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.5.3.2 Activated Carbon Adsorption 

Activated carbon adsorption removes dissolved organic compounds from 

wastewater. Some MP&M facilities use carbon adsorption to polish effluent from ultrafiltration 

systems treating oily wastewater. During adsorption, molecules of a dissolved compound adhere 

to the surface of an adsorbent solid. Activated carbon is an excellent adsorption medium due to 

its large internal surface area, generally high attraction to organic pollutants, and hydrophobic 

nature (i.e., water will not occupy bonding sites and interfere with the adsorption of pollutants). 

Pollutants in the wastewater bond on the activated carbon grains until all the surface bonding 

sites are occupied. At that point, the carbon is considered to be “spent.” Spent carbon requires 

regeneration; regenerated carbon has a reduced adsorption capacity compared to fresh carbon. 

After several regenerations, the carbon is disposed of. 

The carbon fits in granular carbon system vessels, forming a “filter” bed. Vessels 

are usually circular for pressure systems and rectangular for gravity flow systems. For wastewater 

treatment, activated carbon typically is packed into one or more filter beds or columns; a typical 

treatment system consists of multiple filter beds in series. Wastewater flows through the filter 

beds and comes in contact with all portions of the activated carbon. The activated carbon in the 

upper portion of the column is spent first (assuming flow is downward), and progressively lower 

regions of the column are spent as the adsorption zone moves down the unit. When pollutant 

concentrations at the bottom of the column begin to increase above acceptable levels, the entire 

column is considered spent and must be regenerated or removed. 

8.5.3.3 Reverse Osmosis 

Reverse osmosis is a membrane separation technology used by MP&M facilities 

as an in-process step or as an end-of-pipe treatment. Section 8.2.8.2 discusses in-process reverse 

osmosis. In an end-of-pipe application, reverse osmosis typically recycles water and reduces 

discharge volume rather than recovers chemicals. The effluent from a conventional treatment 

system generally has a TDS concentration unacceptable for most rinsing operations, and cannot 

be recycled. Reverse osmosis with or without some pretreatment can replace TDS 

concentrations, and the resulting effluent stream can be used for most rinsing operations. 

8.5.3.4 Ion Exchange 

Ion exchange is both an in-process metals recovery and recycle and end-of-pipe 

polishing technology. Section 8.2.8.1 discusses in-process ion exchange. This technology 

generally uses cation resins to remove metals but sometimes uses both cation and anion columns. 

The regenerant from end-of-pipe ion exchange is not usually amenable to metals recovery as it 

typically contains multiple metals at low concentrations. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.5.4 Sludge Handling 

This subsection discusses the following sludge-handling technologies: 

� Gravity thickening; 

� Pressure filtration; 

� Sludge drying; and 

� Vacuum filtration. 

8.5.4.1 Gravity Thickening 

Gravity thickening is a physical liquid-solid separation technology used to 

dewater wastewater treatment sludge. Sludge feeds from a primary settling tank or clarifier to a 

thickening tank, where gravity separates the supernatant (liquid) from the sludge, increasing the 

sludge density. The supernatant returns to the primary settling tank or the head of the treatment 

system for further treatment. The thickened sludge that collects on the bottom of the tank is 

pumped to additional dewatering equipment or contract hauled for disposal. Figure 8-17 shows a 

diagram of a gravity thickener. 

Figure 8-17. Gravity Thickening 

Facilities where the sludge is to be further dewatered by a mechanical device, such 

as a filter press, generally use gravity thickeners. Increasing the solids content in the thickener 

substantially reduces capital and operating costs of the subsequent dewatering device and also 

reduces the hauling cost. This process is potentially applicable to any MP&M facility that 

generates sludge. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.5.4.2 Pressure Filtration 

The filter press is the most common type of pressure filtration used at MP&M 

facilities for dewatering wastewater treatment sludges. A filter press consists of a series of 

parallel plates pressed together by a hydraulic ram (older models may have a hand crank), with 

cavities between the plates. Figure 8-18 shows a diagram of a plate-and-frame filter press. The 

filter press plates are concave on each side to form cavities and are covered with a filter cloth. At 

the start of a cycle, a hydraulic pump clamps the plates tightly together and a feed pump forces a 

sludge slurry into the cavities of the plates. The liquid (filtrate) escapes through the filter cloth 

and grooves molded into the plates and is forced by the pressure of the feed pump (typically 

around 100 psi) to a discharge port. The filter cloth retains the solids, which remain in the 

cavities. This process continues until the cavities are packed with sludge solids. Some units use 

an air blow-down manifold at the end of the filtration cycle to drain remaining liquid from the 

system, further drying the sludge. The pressure releases and the plates separate. The sludge 

solids or cake is loosened from the cavities and falls into a hopper or drum. A plate filter press 

can produce a sludge cake with a dryness of approximately 20 to 30 percent solids for metal 

hydroxides precipitated with sodium hydroxide, and 30 to 40 percent solids for metal hydroxides 

precipitated with calcium hydroxide. Filter presses are available in a very wide range of 

capacities (0.6 ft3

 to 20 ft3). A typical operating cycle is from 4 to 8 hours, depending on the 

dewatering characteristics of the sludge. Units are usually sized based on one or two cycles per 

day. 

Figure 8-18. Plate-and-Frame Filter Press 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.5.4.3 Vacuum Filtration 

Some MP&M facilities conduct vacuum filtration to reduce the water content of 

metal hydroxide sludge. These MP&M facilities generally use cylindrical drum vacuum filters. 

The filters on these drums typically are either made of natural or synthetic fibers, or a wire-mesh 

fabric. The drum dips into a vat of sludge and rotates slowly. A vacuum inside the drum draws 

sludge to the filter. Water is drawn through the filter to a discharge port, and the dewatered 

sludge is scraped from the filter. Because dewatering sludge with a vacuum filter is relatively 

expensive per kilogram of water removed, the liquid sludge is frequently gravity-thickened prior 

to vacuum filtration. Figure 8-19 shows a typical rotary vacuum filter. Municipal treatment 

plants and a wide variety of industries frequently use vacuum filters. Larger facilities more 

commonly use this technology, as they may have a gravity thickener to double the solids content 

of clarifier sludge before vacuum filtering. Often facilities apply a precoat to inhibit filter 

blinding. 

Figure 8-19. Rotary Vacuum Filter 

Maintenance of vacuum filters involves cleaning or replacing the filter media, 

drainage grids, drainage piping, filter parts, and other parts. Since maintenance time may be as 

high as 20 percent of total operating time, facilities may maintain one or more spare units. If this 

technology is used intermittently, the facility may drain and wash the filter equipment each time 

it is taken out of service. 

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8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.5.4.4 Sludge Drying 

Wastewater treatment sludges are often hauled long distances to disposal 

facilities. The transportation and disposal costs depend mostly on the volume and weight of 

sludge, which is directly related to its water content. Therefore, many MP&M facilities use 

sludge drying equipment following dewatering to further reduce the volume and weight of the 

sludge. The solids content of the sludge dewatered on a filter press usually ranges from 20 to 40 

percent. Drying equipment can produce a waste material with a solids content of approximately 

90 percent. 

There are several design variations for sludge drying equipment. A commonly 

used system consists of an auger or conveyor system to move a thin layer of sludge through a 

drying region and discharge it into a hopper. Various heat sources including electric, electric 

infrared, steam, and gas are used for sludge drying. Some continuous units are designed such 

that the sludge cake discharged from a filter press drops into the feed hopper of the unit, making 

the overall dewatering process more automated. System capacities range from less than 1 ft3/hr 

to more than 20 ft3

/hr of feed. Sludge drying equipment requires an air exhaust system due to the 

fumes generated during drying. 

References 

1.	 Freeman, H.M. Hazardous Waste Minimization. McGraw-Hill Publishing Co., 

1990, p. 39. 

2.	 U.S. Environmental Protection Agency. Development Document for Effluent 

Limitations Guidelines and Standards for the Nonferrous Metals Forming and 

Metal Powders Point Source Category. EPA 440-1-86-019, September 1996. 

3.	 Cushnie, George C. Pollution Prevention and Control Technology for Plating 

Operations. National Center for Manufacturing Sciences, 1994. 

4.	 Brown, T. and LeMay, H. Chemistry - The Central Science, 2nd Edition. PrenticeHall, Inc., 1981, p. 360. 

5.	 AFCEC-TR-76-13, Final Report: Ozone Oxidation of Metal Plating Cyanide 

Wastewater. September 1976. 

6.	 Garrison, R.L. and Monk, C.E. “Advanced Ozone-Oxidation for Complexed 

Cyanides.” Proceedings of the First International Symposium on Ozone for Water 

and Wastewater Treatment, 1973, p. 551. 

7.	 Electric Power Research Institute. Trace Element Removal by Iron Adsorption/ 

Coprecipitator: Process Design Manual. EPRI GS-7005, October 1990. 

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8.6 
8.0 - Pollution Prevention and Wastewater Treatment Technologies 

8.	 Benefield, L. and Judkins, J. Process Chemistry for Water and Wastewater 

Treatment. Prentice-Hall, Inc., 1982, p. 110. 

9.	 Metcalf & Eddy, Inc. Wastewater Engineering: Treatment Disposal and Reuse. 

McGraw-Hill Book Company, 1979, p. 187. 

10.	 Freeman, H.M. Standard Handbook of Hazardous Waste Treatment and Disposal. 

McGraw-Hill Publishing Co., 1989. 

11. Cherry, K.F. Plating Waste Treatment. Ann Arbor Science, 1982. 

12.	 Evans, F.L. Ozone in Water and Wastewater Treatment. Ann Arbor Science, 

1975. 

13.	 Harms, L.L. Chemicals in the Water Treatment Process. Water/Engineering and 

Management, March 1987, pg 32. 

14.	 Eckenfelder, W.W. Principles of Water Quality Management. CBI Publishing Co., 

1980. 

15.	 Texas Natural Resource Conservation Commission. Pollution Prevention for 

Cleaning and Degreasing Operations. www.eponline.com. 

16.	 Ogunbameru, G. Reducing Water Used for Printed Circuit Board Manufacturing. 

Water and Wastewater Products, January 2003. www.wwp-online.com. 

17.	 U.S. EPA, Guidance Document for Developing Best Management Practices 

(BMP),” EPA 833-B–93–004, 1993. 

18.	 NDMA Source Control. Source Control Division, Orange County Sanitation 

District, California. March 27, 2002. www.ocsd.com. 

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9.0 - Technology Options 

9.0 TECHNOLOGY OPTIONS 

This section presents the technology options evaluated by EPA as the basis for the 

final MP&M effluent limitations guidelines and standards. It also describes EPA’s rationale for 

selecting the technology options for the final rule. EPA used the options presented in this section 

as the basis for evaluating Best Practicable Control Technology Currently Available (BPT), Best 

Conventional Pollutant Control Technology (BCT), Best Available Technology Economically 

Achievable (BAT), New Source Performance Standards (NSPS), Pretreatment Standards for 

Existing Sources (PSES), and Pretreatment Standards for New Sources (PSNS). 

EPA is promulgating performance-based limitations and standards for the Oily 

Wastes Subcategory to control direct discharges. These limitation and standards do not require 

the use of any particular pollution prevention or wastewater treatment technology. Rather, a 

facility may use any combination of pollution prevention and wastewater treatment technology to 

comply with the limitations. Direct dischargers must also comply with NPDES regulations (40 

CFR 122). 

Section 9.1 summarizes the methodology EPA used to select the technologies 

included in the options. Sections 9.2 through 9.9 describe the technology options evaluated for 

the final effluent limitations guidelines and standards for each subcategory for each of the 

regulatory levels of control. Section 9.10 summarizes the options for each subcategory 

considered and selected in developing the effluent limitations and standards, and Figures 9-1 

through 9-6 (at the end of this section) present schematic diagrams of the options. 

9.1 Technology Evaluation Methods 

Facilities performing proposed MP&M operations generate wastewater containing 

oils, organic pollutants, cyanide, hexavalent chromium, complexed metals, and dissolved 

metals.1 The technology options considered for the final rule consist of pollution prevention and 

wastewater treatment technologies designed to reduce or eliminate the generation or discharge of 

pollutants from facilities performing proposed MP&M operations. EPA identified these 

technologies from responses to the MP&M detailed and screener surveys, MP&M site visits and 

sampling episodes, and technical literature. EPA then grouped the most common technologies 

according to the type of wastewater treated (e.g., oily wastewater, metal-bearing wastewater, 

cyanide-bearing wastewater), and also by source reduction and pollution prevention technologies, 

recycling technologies, and end-of-pipe treatment technologies. Tables 8-1 through 8-3 in 

Section 8.0 show the in-process and end-of-pipe treatment used by industry as reported in 

industry surveys. 

1

Note: EPA evaluated a number of unit operations for the May 1995 proposal, January 2001 proposal, and June 2002 

NODA (see Tables 4-3 and 4-4). However, EPA selected a subset of these unit operations for regulation in the final 

rule (see Section 1.0). For this section, the term “proposed MP&M operations” means those operations evaluated for 

the two proposals, NODA, and final rule. The term “final MP&M operations” means those operations defined as 

“oily operations” (see Section 1.0, 40 CFR 438.2(f), and Appendix B to Part 438) and regulated by the final rule. 

9-1 
9.0 - Technology Options 

EPA considered a technology to be demonstrated in the industry if the technology 

effectively treated wastewater from proposed MP&M operations and if EPA observed the 

technology during at least one MP&M site visit or at least one survey respondent reported using 

the technology. EPA evaluated the performance of each technology in terms of percent removal 

and final effluent concentration using analytical data available from MP&M sampling episodes, 

discharge monitoring reports and periodic compliance reports, previous effluent guidelines data 

collection efforts, and quantitative and qualitative assessments from engineering site visits, 

comment submittals, and literature. 

EPA evaluated several technology options for direct dischargers in the 

subcategories listed in the January 2001 proposal (i.e., General Metals, Metal Finishing Job 

Shops, Printed Wiring Board, Non-Chromium Anodizing, Steel Forming and Finishing, Oily 

Wastes, Railroad Line Maintenance, and Shipbuilding Dry Dock). 

General Metals Subcategory 

EPA is not revising or establishing any limitations or standards for facilities that 

would have been subject to this subcategory. Such facilities will continue to be regulated by the 

General Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, 

as applicable. 

9.2.1 Best Practicable Control Technology Currently Available (BPT) 

The following discussion describes the technology options considered for the 

proposed General Metals Subcategory. Facilities in this proposed subcategory generate metalbearing wastewater but may also generate some oily wastewater (see Section 6.0). 

Option 1 

Option 1 includes segregation and preliminary treatment of oily wastewater, 

cyanide-bearing wastewater, hexavalent chromium-bearing wastewater, and complexed metalbearing wastewater, followed by chemical precipitation using either sodium hydroxide or lime, 

sedimentation using a clarifier, and sludge removal using gravity thickening and a filter press. 

Segregation of wastewater and subsequent preliminary treatment allows for the most efficient, 

effective, and economical means of removing pollutants in certain wastewater streams. These 

streams contain pollutants (e.g., oil and grease, cyanide, hexavalent chromium, chelated metals, 

and organic solvents) that can inhibit the performance of chemical precipitation and 

sedimentation treatment, while increasing the overall treatment costs. For example, if a facility 

segregates its oil-bearing wastewater from its metal-bearing wastewater, then the facility can 

design an oil removal treatment technology based on only the oily waste flow volume and not on 

the combined metal-bearing and oil-bearing wastewater flow, decreasing the size of the overall 

treatment system. Treatment chemical costs are also reduced because of the reduced volume. 

Preliminary treatment technologies for these types of wastewater streams are described below. 

9-2


9.2 
9.0 - Technology Options 

(see Section 5.0 and Appendix C for a more detailed description of each of these wastewater 

streams). 

� Oil-Bearing Wastewater. Alkaline cleaning wastewater and water-based 

metal-working fluids (e.g., machining and grinding coolants) typically 

contain significant amounts of oil and grease. These wastewater streams 

require preliminary treatment to remove oil and grease and organic 

pollutants. Option 1 includes a preliminary treatment step for these 

wastewaters consisting of chemical emulsion breaking followed by gravity 

separation of oil and water (oil/water separator or gravity flotation). 

� Cyanide-Bearing Wastewater. The industry generates several types of 

wastewater that may contain significant amounts of cyanide, such as 

electroplating and cleaning wastewater. Option 1 includes a preliminary 

treatment step for these wastewaters consisting of alkaline chlorination 

with sodium hypochlorite. 

� Hexavalent Chromium-Bearing Wastewater. The industry generates 

several types of wastewater that contain hexavalent chromium, usually 

from acid treatment, anodizing, conversion coating, and electroplating. 

Because hexavalent chromium does not form an insoluble hydroxide, this 

wastewater requires chemical reduction of the hexavalent chromium to 

trivalent chromium prior to chemical precipitation and sedimentation. 

Trivalent chromium forms an insoluble hydroxide and is treated by 

chemical precipitation and sedimentation. Option 1 includes a preliminary 

treatment step for these wastewaters consisting of chromium reduction 

using sodium metabisulfite. 

� Chelated Metal-Bearing Wastewater. Electroless plating and some 

cleaning operations generate wastewater that contains significant amounts 

of chelated metals. This wastewater requires chemical reduction to break 

the metal-chelate bond or reduce the metal-chelate complex to an insoluble 

state so that it can be removed during chemical precipitation. Option 1 

includes a preliminary treatment step for these wastewaters consisting of 

chemical reduction using sodium borohydride, dithiocarbamate, hydrazine, 

or sodium hydrosulfite. 

� Organic Solvent-Bearing Wastewater. Option 1 also includes contract 

hauling of solvent degreasing wastewater, where applicable. Based on the 

MP&M surveys and site visits, most solvent degreasing operations that use 

organic solvents (e.g., 1,1,1-trichloroethane, trichloroethene) are contract 

hauled for off-site recycling. Some facilities performing proposed MP&M 

operations reported using organic solvent/water mixtures or rinses 

9-3

9.0 - Technology Options 

following organic solvent degreasing. EPA found contract hauling of this 

wastewater to be the most common disposal method for these sites. 

After pretreatment of the applicable segregated streams, the Option 1 technology 

basis is chemical precipitation and gravity clarification. Chemical precipitation adjusts the pH of 

the wastewater with alkaline chemicals such as lime (calcium hydroxide) or caustic (sodium 

hydroxide) or acidic chemicals (such as sulfuric acid) to produce insoluble metal hydroxides. 

This step is followed by a gravity settling process in a clarifier to remove the precipitated and 

flocculated metal hydroxides. Sludge is then thickened in a gravity-thickening unit. The sludge 

is then sent to a filter press used to remove excess wastewater, which is generally recycled back 

to the clarifier. 

The technology components that many facilities performing proposed MP&M 

operations currently use are equivalent to those described for Option 1. Differences in the level 

of performance (i.e., effluent limitations) between current discharges and Option 1 derive from 

improvements in operation and control of process operations and pollutant control technology. 

EPA’s technical database developed for this rule, including industry survey, site visit, and 

sampling information collected during the period from 1989 through 2001, demonstrate 

significant progress by the industry in reducing pollutants in wastewater discharges beyond the 

existing regulatory standards. For example, sites are moving toward greater implementation of 

pollution prevention and water reduction, including progression to zero discharge when possible. 

In addition, improvements in treatment controls allow for more automated controls, which leads 

to more consistent process operation and wastewater treatment. Finally, advances in wastewater 

treatment chemicals also result in higher treatment efficiencies. 

Option 2 

Option 2 builds on Option 1 by adding the following in-process pollution 

prevention, recycling, and water conservation methods that allow for recovery and reuse of 

materials: 

� Two-stage countercurrent cascade rinsing for all flowing rinses; 

� Centrifugation and recycling of painting water curtains; and 

� Centrifugation, pasteurization, and recycling of water-soluble machining 

coolants. 

Option 2S 

Option 2S includes the technologies that compose Option 2 plus a sand filter after 

the clarifier to further remove residual suspended solids from chemical precipitation and 

clarification effluent. 

9-4

9.0 - Technology Options 

Option 3 

In Option 3, an ultrafilter replaces the Option 1 chemical emulsion breaking and 

oil/water separator to remove oil and grease, and a microfilter replaces the Option 1 clarifier. 

Option 4 

Option 4 includes the technologies in Option 3 plus the in-process flow control 

and pollution prevention technologies described in Option 2, allowing recovery and reuse of 

materials along with water conservation. 

Best Professional Judgment (BPJ) to Part 433 Option 

EPA also considered transferring limitations from existing Metal Finishing 

effluent guidelines (40 CFR 433) to the General Metals Subcategory. The technology basis for 

Part 433 includes the following: (1) segregation of wastewater streams; (2) preliminary treatment 

steps as necessary (including oils removal using chemical emulsion breaking and oil/water 

separation, alkaline chlorination for cyanide destruction, reduction of hexavalent chromium, and 

chelation breaking); (3) chemical precipitation using sodium hydroxide; (4) sedimentation using 

a clarifier; and (5) sludge removal (i.e., gravity thickening and filter press). 

Option Selection Discussion 

As discussed in the 2001 proposal (see 66 FR 451), EPA dropped Options 1 and 3 

from further consideration because Options 2 and 4, respectively, cost less and provided greater 

pollutant removals. After proposal, EPA also dropped Option 4 from further consideration for 

the final rule because of its increased cost and lack of significant additional pollutant removals 

beyond Option 2. In addition, comments submitted on the proposed rule questioned the 

completeness of EPA’s database on microfiltration (Option 4), noting that EPA transferred 

limitations for several pollutants from the Option 2 technology based on lack of data. 

EPA dropped Option 2S from further consideration for the final rule for the 

reasons outlined in the 2002 Notice of Data Availability (NODA) (67 FR 38767). First, Option 

2S results in greatly increased cost and minimal increased pollutant removals beyond Option 2. 

Second, EPA believes, after incorporating additional treatment performance data and revising the 

statistical methodology used for calculating numerical limitations (see Section 10.0), the Option 

2 limitations are consistently achievable without adding a sand filter. Therefore, for the final 

rule, EPA considered Option 2 and “BPJ to Part 433 Option” as the basis for limitations for BPT 

for the General Metals Subcategory. See Sections 11.0 and 12.0 for the final estimated 

compliance costs and pollutant removals for Option 2. 

EPA proposed to establish BPT limitations for existing direct dischargers in the 

General Metals Subcategory based on the Option 2 technology. EPA evaluated the cost of 

achieving effluent reductions, pollutant reductions, and the economic achievability of compliance 

9-5

9.0 - Technology Options 

with BPT limitations based on the Option 2 technology and the level of the pollutant reductions 

resulting from compliance with such limitations. EPA has decided not to establish BPT 

limitations for existing direct dischargers in the proposed General Metals Subcategory. The 2001 

proposal also contains detailed discussions on why EPA rejected BPT limitations based on other 

BPT technology options (see 66 FR 452). The information in the rulemaking record for the final 

rule provides no basis for EPA to change this conclusion. 

Those facilities potentially regulated in the General Metals Subcategory include 

facilities that are currently subject to effluent limitations guideline regulation under 40 CFR 433 

as well as facilities not currently subject to national regulation. Approximately 263 of the 266 

existing General Metals direct dischargers (estimated from survey weights for 31 surveyed 

facilities) are currently covered by the Metal Finishing effluent guidelines at Part 433. The 

remaining three facilities (estimated from a survey weight for one surveyed facility) are currently 

directly discharging metal-bearing wastewaters (e.g., salt bath descaling) but are not covered by 

existing Metal Finishing effluent guidelines. EPA’s review of discharge monitoring data and 

unit operations for this surveyed non-433 General Metals facility (with a survey weight of 

approximately three) indicates that this facility is already achieving Part 433 limitations because 

this facility has discharges that closely mirror those required by Part 433. 

The facilities that are currently subject to Part 433 regulations and those facilities 

achieving Part 433 discharge levels, in most cases, have already installed effective pollution 

control technology that includes many of the components of the Option 2 technology. 

Approximately 30 percent of the direct discharging facilities in the General Metals Subcategory 

currently use chemical precipitation followed by a clarifier. Further, EPA estimates that 

compliance with BPT limitations based on the Option 2 technology would result in no closures 

of the existing direct dischargers in the General Metals Subcategory. EPA also notes that the 

adoption of this level of control would also reduce the pollutants discharged into the environment 

by facilities in this subcategory. For facilities in the General Metals Subcategory at Option 2, 

EPA estimates an annual compliance cost of $23.7 million (2001$). Using the method described 

in Section 12.0 to estimate baseline pollutant loadings, EPA estimates Option 2 pollutant 

removals of 417,477 pounds of conventional pollutants and 33,716 pounds of priority metal and 

organic pollutants from current discharges into the Nation’s waters. 

Evaluated under its traditional yardstick, EPA calculated that the effluent 

reductions are achieved at a cost of $18.1/pound-pollutant removed (2001$) for the General 

Metals Subcategory at Option 2. To estimate all pounds of pollutant removed by Option 2 

technology for direct dischargers in the General Metals Subcategory, EPA used the revised 

method described in Section 12.0 to estimate baseline pollutant loadings as the sum of chemical 

oxygen demand (COD) pounds removed plus the sum of all metals pounds removed. EPA used 

the combination of COD pounds removed plus the sum of all metals pounds removed to avoid 

any significant double counting of pollutants. 

As previously stated, EPA received many comments on its estimation of baseline 

pollutant loadings and reductions for the various options presented in the January 2001 proposal. 

9-6

9.0 - Technology Options 

In response to these comments, EPA solicited comment in the June 2002 NODA on alternative 

methods to estimate baseline pollutant loadings. Commentors on the NODA were generally 

supportive of EPA’s alternative methods to estimate baseline pollutant loadings. In particular, 

commentors noted that more accurate estimates of baseline pollutant loadings could be achieved 

by using DMR data. In response to these NODA comments, EPA combined the alternative 

methods in the NODA into the EPA Costs & Loadings Model for the final rule (see Sections 11.0 

and 12.0). 

EPA also received comment on the parameter or parameters it should use for 

estimating total pounds removed by the selected technology option. EPA selected the sum of 

COD and all metals pounds removed for the final rule to compare effluent reductions and 

compliance costs. This approach avoided any significant double counting of pollutants and also 

provided a reasonable estimate of total pounds removed by Option 2 for the General Metals 

Subcategory. Option 2 technology segregates wastewaters into at least five different waste 

streams, each of which have one or two treatment steps. For example, segregated oily 

wastewaters have two treatment steps under Option 2 technology as they are first treated by 

chemical emulsion breaking-oil/water separation and then by chemical precipitation and 

sedimentation. These segregated wastestreams can be loosely grouped together as either oily 

wastewaters or metal-bearing wastewaters. EPA’s use of COD pounds removed for Option 2 

technology generally represents the removal of pollutants from the segregated oily wastewaters. 

EPA’s use of total metals pounds removed for Option 2 technology generally represents the 

removal of pollutants from the segregated metal-bearing wastewaters. 

EPA also considered alternative parameters for calculating total pounds removed 

by Option 2 for the comparison of effluent reductions and compliance costs for the General 

Metals Subcategory. In particular, EPA calculated a ratio of less than $14/pound-pollutant 

removed (2001$) for the General Metals Subcategory at Option 2 when EPA used the highest set 

of pollutants removed per facility with no significant double counting of pollutants (i.e., highest 

per facility pollutant removals of: (1) COD plus total metals; (2) oil and grease (as HEM) plus 

total metals; or (3) oil and grease (as HEM) plus total suspended solids (TSS)). EPA used the 

highest per facility pollutant removals as a confirmation of its primary method for calculating 

baseline pollutant loadings (see Section 12.0) and Option 2 for General Metals Subcategory. 

Based on the revisions and corrections to the EPA Costs & Loadings Model 

discussed in the June 2002 NODA and in Sections 11.0 and 12.0, EPA has decided not to adopt 

BPT limitations based on Option 2 technology. A number of factors supports EPA’s conclusion 

that BPT limitations based on Option 2 technology do not represent effluent reduction levels 

attainable by the best practicable technology currently available. As previously noted, a 

substantial number of facilities that would be subject to limitations as General Metals facilities 

are already regulated by BPT/BAT Part 433 limitations and other facilities are de facto Part 433 

facilities if characterized by their discharges. Thus, establishing BPT limitations for a new 

General Metals Subcategory would effectively revise existing BPT/BAT limitations with respect 

to those facilities. In this case, EPA felt that since the Agency is revising BPT/BAT limitations 

for a significant portion of an industry, it should further review the effluent reductions achieved, 

9-7

9.0 - Technology Options 

and corresponding costs, for Option 2 technology. Such an examination shows that, while the 

Option 2 technology would remove additional pollutants at costs in the middle of the range EPA 

has traditionally determined are reasonable, the costs of the additional removals of toxic 

pollutants are substantially greater. In developing the final rule, EPA determined that, where a 

substantial portion of a subcategory is already subject to effluent limitations guidelines that 

achieve significant removal, the Agency should not promulgate the proposed BPT limitations 

because the limitations would achieve additional toxic removals at a cost ($1,000/pound 

equivalent (PE) in 1981$) substantially greater than that EPA has typically imposed for BAT 

technology in other industries (generally less than $200/PE in 1981$). 

EPA also considered transferring limitations from existing Metal Finishing 

effluent guidelines (40 CFR 433) to the General Metals Subcategory. The technology basis for 

Part 433 includes the following: (1) segregation of wastewater streams; (2) preliminary treatment 

steps as necessary (including oils removal using chemical emulsion breaking and oil/water 

separation, alkaline chlorination for cyanide destruction, reduction of hexavalent chromium, and 

chelation breaking); (3) chemical precipitation using sodium hydroxide; (4) sedimentation using 

a clarifier; and (5) sludge removal (i.e., gravity thickening and filter press). 

Approximately 99 percent of the existing direct dischargers in the General Metals 

Subcategory are currently covered by the existing Metal Finishing effluent guidelines. The 

remaining 1 percent (an estimated three facilities nationwide based on the survey weight 

associated with one surveyed facility) are currently permitted to discharge metal-bearing 

wastewaters but are not covered by the existing Metal Finishing effluent guidelines. EPA's 

review of discharge monitoring data and unit operations for this surveyed non-433 General 

Metals facility (with a survey weight of approximately three) indicates that this facility is subject 

to permit limitations established on a BPJ basis that are equivalent or more stringent than Part 

433 limitations. Transferring limitations from existing Metal Finishing effluent guidelines would 

likely result in no additional pollutant load reductions. Therefore, based on the lack of additional 

pollutant removals that are estimated, EPA is not promulgating BPT limitations transferred from 

existing Metal Finishing effluent limitations guidelines for the General Metals Subcategory. 

EPA is not revising or establishing BPT limitations for any facilities in this 

subcategory. Direct dischargers in the General Metals Subcategory will remain regulated by 

permit limits and Part 433, as applicable. 

9.2.2 Best Conventional Pollutant Control Technology (BCT) 

In deciding whether to adopt more stringent limitations for BCT than BPT, EPA 

considers whether there are technologies that achieve greater removals of conventional pollutants 

than those adopted for BPT, and whether those technologies are cost-reasonable under the 

standards established by the CWA. EPA generally refers to the decision criteria as the “BCT cost 

test.” For a more detailed description of the BCT cost test and details of EPA’s analysis, see 

Chapter 4 of the Economic, Environmental, and Benefits Analysis of the Final Metal Products & 

Machinery Rule (EEBA) (EPA-821-B-03-002). 

9-8

9.0 - Technology Options 

As EPA is not establishing any BPT limitations for the General Metals 

Subcategory, EPA did not evaluate any technologies for the final rule that can achieve greater 

removals of conventional pollutants. Consequently, EPA is not establishing BCT limitations for 

the General Metals Subcategory. 

9.2.3 Best Available Technology Economically Achievable (BAT) 

EPA proposed to establish BAT limitations for existing direct dischargers in the 

General Metals Subcategory based on the Option 2 technology. As discussed in Section 9.2.1, 

EPA has decided not to establish BPT limitations based on Option 2 technology. For the same 

reasons, EPA is not establishing BAT limitations based on the same technology. EPA evaluated 

the cost of effluent reductions, pollutant reductions, and the economic achievability of 

compliance with BAT limitations based on the Option 2 technology. 

Based on the revisions and corrections to the EPA Costs & Loadings Model 

discussed in the NODA, preamble to the final rule, and in Sections 11.0 and 12.0, EPA 

determined that the costs of Option 2 are disproportionate to the toxic pollutant reductions 

(measured in PE). The cost of achieving the effluent reduction (in 1981$) for Option 2 for direct 

dischargers in the General Metals Subcategory is over $1,000/PE removed (see the EEBA and 

Section 26.0 of the rulemaking record, DCN 37900, for a discussion of the cost-effectiveness 

analysis). The costs associated with this technology are, as previously noted, substantially greater 

than the level EPA has traditionally determined are associated with available toxic pollutant 

control technology. EPA has determined that Option 2 technology is not the best available 

technology economically achievable for existing direct dischargers in the General Metals 

Subcategory. Therefore, EPA is not revising or establishing BAT limitations for this subcategory 

based Option 2 technology. 

EPA also considered transferring BAT limitations from existing Metal Finishing 

effluent guidelines (40 CFR 433.14) to the General Metals Subcategory (see “BPJ to Part 433 

Option” in Section 9.2.1). EPA reviewed existing General Metals facilities and found that all are 

currently achieving Part 433 BAT limitations. Transferring BAT limitations from existing Metal 

Finishing effluent guidelines would likely result in no additional pollutant load reductions and 

minimal incremental compliance costs (see Section 9.2.1). Therefore, based on the lack of 

additional pollutant removals that are estimated, EPA is not promulgating BAT limitations 

transferred from existing Metal Finishing effluent limitations guidelines for the General Metals 

Subcategory. 

EPA is not revising or establishing BAT limitations for any facilities in this 

subcategory. Direct dischargers in the General Metals Subcategory will remain regulated by 

permit limits and Part 433, as applicable. 

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9.0 - Technology Options 

9.2.4 New Source Performance Standards (NSPS) 

EPA proposed NSPS for the General Metals Subcategory based on Option 4 

technology (see Section 9.2.1). Option 4 technology is similar to Option 2 (including Option 2 

flow control and pollution prevention) but includes oils removal using ultrafiltration and solids 

separation by a microfilter (instead of a clarifier). Commentors stated that EPA had under-costed 

the Option 4 technology and that the compliance costs would be a barrier to entry for new 

facilities. In addition, commentors questioned the completeness of EPA’s database on 

microfiltration, noting that EPA transferred standards for several pollutants from the Option 2 

technology, based on lack of data. EPA reviewed its database for the Option 4 technology and 

agrees that its microfiltration database is insufficient to support a determination that the Option 4 

limitations are technically achievable. 

EPA also evaluated setting General Metals NSPS based on the Option 2 

technology and assessed the financial burden to new General Metals direct dischargers. 

Specifically, EPA’s ‘barrier-to-entry’ analysis identified whether General Metals NSPS based on 

the Option 2 technology would pose sufficient financial burden as to constitute a material barrier 

to entry of new General Metals establishments into the MP&M Point Source Category. 

Additionally, EPA reviewed its database for establishing General Metals NSPS based on the 

Option 2 technology as commentors indicated the proposed standards were not technically 

achievable. 

In response to these comments, EPA reviewed all the information currently 

available on General Metals facilities employing Option 2 technology. This review demonstrated 

that process wastewaters at General Metals facilities contain a wide variety of metals in 

significant concentrations. Commentors stated that single-stage precipitation and solids 

separation steps may not achieve sufficient removals for wastewaters that contain significant 

concentrations of a wide variety of metals - especially if the metals preferentially precipitate at 

disparate pH ranges. Consequently, to address concerns raised by commentors, EPA also costed 

new sources to operate two separate chemical precipitation and solids separation steps in series. 

Two-stage chemical precipitation and solids separation allows General Metals facilities with 

multiple metals to control metal discharges to concentrations lower than single-stage chemical 

precipitation and solids separation over a wider pH range. 

Applying this revised costing approach, EPA projects a barrier to entry for 

General Metals NSPS based on the Option 2 technology because 14 percent of General Metals 

direct dischargers have after-tax compliance costs between 1 to 3 percent of revenue, 22 percent 

have after-tax compliance costs between 3 to 5 percent of revenue, and 2 percent have after-tax 

compliance costs greater than 5 percent of revenue. Consequently, based on the compliance 

costs of the modified Option 2 technology, EPA rejected Option 2 technology as the basis for 

NSPS in the General Metals Subcategory. See Section 11.0 for a description of how these new 

source compliance costs were developed and Chapter 9 of the EEBA for a description of the 

framework EPA used for the barrier-to-entry analysis and general discussion of the results. 

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9.0 - Technology Options 

EPA also considered transferring NSPS from existing Metal Finishing effluent 

guidelines (40 CFR 433.16) to the General Metals Subcategory. EPA reviewed existing General 

Metals direct dischargers and found that all are currently either covered by or have permits based 

on the Metal Finishing limitations at 40 CFR 433. EPA has no basis to conclude that new 

General Metals facilities would have less stringent requirements than existing facilities, 

particularly since, in the absence of promulgated NSPS, it is likely that permit writers would 

consult the Part 433 requirements to establish BPJ limits. In addition, those new facilities which 

meet the applicability criteria for Part 433 will be subject to the NSPS for that category. 

Therefore, transferring standards from these existing Metal Finishing effluent limitations 

guidelines would likely result in no additional pollutant load reductions. 

Therefore, based on the lack of additional pollutant removals that are estimated, 

EPA is not promulgating NSPS for the General Metals Subcategory. EPA is not revising or 

establishing NSPS for any facilities in this subcategory. Direct dischargers in the General Metals 

Subcategory will remain regulated by permit limits and Part 433, as applicable. 

9.2.5 Pretreatment Standards for Existing Sources (PSES) 

As discussed in the June 2002 NODA (67 FR 38798), EPA also considered a 

number of alternative options whose economic impacts would be less costly than Option 2 

technology. These options potentially have compliance costs more closely aligned with toxic 

pollutant reductions. EPA considered the following alternative options for the final rule: 

� Option A: No change in current regulation. 

� Option B: Option 2 with a higher low-flow exclusion. 

� Option C: Upgrading facilities currently covered by Part 413 to meet the 

PSES of Part 433 (“413 to 433 Upgrade Option” described below). 

� Option D: Upgrading all facilities covered by Part 413 and those facilities 

covered by “local limits only” that discharge greater than a specified 

wastewater flow (e.g., 1, 3, or 6.25 million gallons per year (MGY)) of 

process wastewater to meet the PSES of Part 433 (“Local Limits to 433 

Upgrade Option” described below). Note that facilities regulated by “local 

limits only” are also regulated by the General Pretreatment Standards (40 

CFR 403). 

413 to 433 Upgrade Option 

The 413 to 433 Upgrade Option would require those facilities currently required 

to meet the standards of the Electroplating effluent limitations guidelines (40 CFR 413) to meet 

the limitations and standards of the Metal Finishing effluent guidelines (40 CFR 433). Currently, 

the only facilities that are still completely covered by the Electroplating effluent guidelines are 

9-11

9.0 - Technology Options 

indirect dischargers that were in existence prior to 1982 and have not significantly upgraded their 

operations. Therefore, this alternative option applies to only a subset of indirect dischargers 

within the proposed General Metals, Metal Finishing Job Shops, Printed Wiring Board, and NonChromium Anodizing Subcategories. 

The technology components that compose the basis for the 413 to 433 Upgrade 

Option are equivalent to those described for Option 1. Differences in the level of performance 

(i.e., effluent limitations) between the 413 to 433 Upgrade Option and Option 1 derive from 

improvements in operation and control of process operations and pollutant control technology 

since the early 1980s when the Electroplating effluent guidelines were developed. 

Local Limits to 433 Upgrade Option 

This option would upgrade all facilities covered by Part 413 and those facilities 

covered by “local limits only” that discharge greater than a specified wastewater flow (e.g., 1, 3, 

or 6.25 million gallons per year) of process wastewater to meet the PSES of Part 433. 

Accordingly, this technology option applies to only a subset of indirect dischargers within the 

proposed General Metals Subcategory. A separate but similar alternative option (see Section 

9.2.1) applies to direct dischargers. 

The technology components that compose the basis for the Local Limits to 433 

Upgrade Option are equivalent to those described for Option 1. Differences in treatment 

performance (i.e., effluent limitations) between the Local Limits to 433 Upgrade Option and 

Option 1 derive from improvements in operation and control of pollutant control technology 

implemented since the early 1980s when the Electroplating effluent guidelines were developed. 

Option Selection Discussion 

EPA proposed to establish PSES for existing indirect dischargers in the General 

Metals Subcategory based on the Option 2 technology (i.e., the same technology basis that EPA 

considered for BPT/BCT/BAT for this subcategory) with a “low-flow” exclusion of 1 MGY to 

reduce economic impacts on small businesses and administrative burden for control authorities. 

Based on the revisions and corrections to the EPA Costs & Loadings Model discussed in the 

NODA, preamble to the final rule, and in Sections 11.0 and 12.0, EPA rejected promulgating 

PSES for existing indirect dischargers in the General Metals Subcategory based on the Option 2 

technology for the following reasons: (1) many General Metals indirect dischargers are currently 

regulated by existing effluent guidelines (Parts 413 or 433 or both, as applicable); (2) EPA 

estimates that compliance with PSES based on the Option 2 technology will result in the closure 

of approximately 4 percent of the existing indirect dischargers in this subcategory; and (3) EPA 

determined that the incremental toxic pollutant reductions are very expensive per pound removed 

(the cost-effectiveness value (in 1981$) for Option 2 for indirect dischargers in the General 

Metals Subcategory is $432/PE). 

9-12

9.0 - Technology Options 

This suggests to EPA that the identified technology is not truly “available” to this 

industry because it would remove a relatively small number of additional toxic pounds at a cost 

significantly greater than that EPA has typically determined is appropriate for other industries. 

Therefore, EPA has determined that Option 2 technology is not the best available technology 

economically achievable for existing indirect dischargers in the General Metals Subcategory, and 

is not establishing PSES for this subcategory based on the Option 2 technology. 

Based on the revisions and corrections to the EPA Costs & Loadings Model 

discussed in the NODA, preamble to the final rule, and in Sections 11.0 and 12.0, EPA has 

revised its methodology for estimating compliance costs and pollutant loadings for Option 2, 

higher low-flow exclusions (Option B), and the “upgrade” options (Options C and D) previously 

described. Using information from this revised analysis, EPA concludes that all of these 

alternative options (Options B, C, and D) are either not available or not economically achievable. 

EPA rejected Options B, C, and D because: (1) more than 10 percent of existing indirect 

dischargers not covered by Part 433 close at the upgrade option; or (2) toxic removals of the 

upgrade options are quite expensive (cost-effectiveness values (in 1981$) in excess of $420/PE), 

suggesting that these options are not truly available technologies for this industry segment. 

EPA consequently determined that none of the treatment options represented best 

available technology economically achievable. Therefore, EPA is not revising or establishing 

PSES for existing indirect dischargers in the General Metals Subcategory (Option A). 

Wastewater discharges to POTWs from facilities in this subcategory will remain regulated by 

local limits, General Pretreatment Standards (Part 403), and Parts 413 and/or 433, as applicable. 

EPA also notes that facilities regulated by Parts 413 and/or 433 PSES must comply with Part 433 

PSNS if the changes to their facilities are determined to make them new sources. 

9.2.6 Pretreatment Standards for New Sources (PSNS) 

In 2001, EPA proposed pretreatment standards for new sources based on the 

Option 4 technology basis. Option 4 technology is similar to Option 2 (including Option 2 flow 

control and pollution prevention) but includes oils removal using ultrafiltration and solids 

separation by a microfilter (instead of a clarifier). As explained in Section 9.2.4, EPA concluded 

that its database is insufficient to support a determination that the Option 4 standards are 

technically achievable. As a result, for the final rule, EPA considered establishing PSNS in the 

General Metals Subcategory based on the Option 2 technology (i.e., the same technology basis 

that was considered for BPT/BCT/BAT for this subcategory) along with the same “low-flow” 

exemption of 1 MGY considered for existing sources. 

For the final rule, EPA evaluated setting General Metals PSNS based on the 

Option 2 technology and assessed the financial burden to new General Metals indirect 

dischargers. Specifically, EPA's ‘barrier-to-entry' analysis identified whether General Metals 

PSNS based on the Option 2 technology would pose sufficient financial burden on new General 

Metals facilities to constitute a material barrier to entry into the MP&M Point Source Category. 

9-13

9.0 - Technology Options 

EPA projects a barrier to entry for General Metals PSNS based on the Option 2 

technology because 14 percent of General Metals indirect dischargers have after-tax compliance 

costs between 1 to 3 percent of revenue and 20 percent have after-tax compliance costs between 

3 to 5 percent of revenue. Consequently, EPA rejected Option 2 technology as the basis for 

PSNS in the General Metals Subcategory. EPA has selected “no further regulation,” and is not 

revising PSNS for new General Metals indirect dischargers. Wastewater discharges to POTWs 

from facilities in this subcategory will remain regulated by local limits, General Pretreatment 

Standards (Part 403), and Part 433, as applicable. See Section 11.0 for a description of how 

these new source compliance costs were developed and Chapter 9 of the EEBA for a description 

of the framework EPA used for the barrier-to-entry analysis and general discussion of the results. 

Metal Finishing Job Shops Subcategory 

EPA is not revising any limitations or standards for facilities that would have been 

subject to this subcategory. Such facilities will continue to be regulated by the General 

Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, as 

applicable. 

9.3.1 BPT, BCT, and BAT 

EPA evaluated several technology options for direct dischargers for the Metal 

Finishing Job Shops (MFJS) Subcategory. Facilities in this subcategory perform unit operations 

that primarily generate metal-bearing wastewater, but may also generate some oily wastewater. 

EPA evaluated Options 1, 2, 2S, 3, and 4, which are described in detail in Section 9.2.1. As 

discussed in Section 9.2.1, EPA dropped Options 1, 2S, 3, and 4 from further consideration. 

Therefore, for the final rule, EPA considered only Option 2 as the basis for limitations for the 

MFJS Subcategory. See Sections 11.0 and 12.0 for the final estimated compliance costs and 

pollutant loadings for Option 2. 

EPA proposed to establish BPT/BCT/BAT for existing direct dischargers in the 

MFJS Subcategory based on the Option 2 technology (see Section 9.2.1 for a description of 

Option 2). EPA evaluated the cost of effluent reductions, pollutant reductions, and the economic 

achievability of compliance with BPT/BCT/BAT limitations based on the Option 2 technology. 

Based on the revisions and corrections to the EPA Costs & Loadings Model discussed in the 

NODA, preamble to the final rule, and in Sections 11.0 and 12.0, EPA determined that the 

compliance costs of the Option 2 technology are not economically achievable. 

EPA estimates that compliance with BPT/BCT/BAT limitations based on the 

Option 2 technology will result in the closure of 50 percent of the existing direct dischargers in 

this subcategory (12 of 24 existing MFJS direct dischargers). Consequently, EPA concludes that, 

for existing direct dischargers in the MFJS Subcategory, Option 2 is not the best practicable 

control technology, best conventional pollutant control technology, or best available technology 

economically achievable. EPA has decided not to establish new BPT, BCT, or BAT limitations 

9-14


9.3 
9.0 - Technology Options 

for existing MFJS direct dischargers based on the Option 2 technology; these discharges will 

remain subject to Part 433. 

9.3.2 NSPS 

EPA proposed to establish NSPS for new direct dischargers in the MFJS 

Subcategory based on the Option 4 technology. Option 4 technology is similar to Option 2 

(including Option 2 flow control and pollution prevention) but includes oils removal using 

ultrafiltration and solids separation by a microfilter (instead of a clarifier). As explained in 

Section 9.2.4, EPA concluded that its database is insufficient to support a determination that the 

Option 4 standards are technically achievable. Consequently, EPA rejected Option 4 technology 

as the basis for NSPS in the MFJS Subcategory. 

For the final rule, EPA evaluated setting MFJS NSPS based on the Option 2 

technology and assessed the financial burden to new MFJS direct dischargers. Specifically, 

EPA’s ‘barrier-to-entry’ analysis identified whether MFJS NSPS based on the Option 2 

technology would pose sufficient financial burden so as to constitute a material barrier to entry 

into the MP&M point source category. Additionally, EPA reviewed its database for establishing 

MFJS NSPS based on the Option 2 technology as commentors indicated the proposed standards 

were not technically achievable. 

In response to these comments, EPA reviewed all the information currently 

available on MFJS facilities using the Option 2 technology basis. This review demonstrated that 

process wastewaters at MFJS facilities contain a wide variety of metals in significant 

concentrations. Commentors stated that single-stage precipitation and solids separation may not 

achieve sufficient removals for wastewaters that contain significant concentrations of a wide 

variety of metals, especially if the metals preferentially precipitate at disparate pH ranges. 

Consequently, to address concerns raised by commentors, EPA also costed new sources to 

operate two separate chemical precipitation and solids separation steps in series. Two-stage 

chemical precipitation and solids separation allows MFJS facilities with multiple metals to 

control metal discharges to concentrations lower than single-stage chemical precipitation and 

solids separation over a wider pH range. 

Applying this revised costing approach, EPA projects a barrier to entry for MFJS 

NSPS based on the Option 2 technology because all MFJS direct dischargers have new source 

compliance costs that are greater than 5 percent of revenue. Consequently, EPA rejected Option 

2 technology as the basis for NSPS in the MFJS Subcategory, and is not revising NSPS for new 

MFJS direct dischargers. Wastewater discharges from these facilities in this subcategory will 

remain regulated by local limits and Part 433 NSPS as applicable. See Section 11.0 for a 

description of how these new source compliance costs were developed and Chapter 9 of the 

EEBA for a description of the framework EPA used for the barrier-to-entry analysis and general 

discussion of the results. 

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9.0 - Technology Options 

9.3.3 PSES 

EPA evaluated several technology options for indirect dischargers for the MFJS 

Subcategory, whose unit operations primarily generate metal-bearing wastewater, but may also 

generate some oily wastewater. These include the same option as evaluated for BAT (i.e., 

Option 2), as well as several alternative options discussed below. EPA did not further evaluate 

Options 1, 2S, 3, and 4 for the final rule for the same reasons as explained for BPT above. See 

Sections 11.0 and 12.0 for the final estimated compliance costs and pollutant loadings for Option 

2 and the alternative options considered for the final rule. 

EPA proposed to establish PSES for existing indirect dischargers in the MFJS 

Subcategory based on the Option 2 technology. Based on the revisions and corrections to the 

EPA Costs & Loadings Model discussed in the NODA, preamble to the final rule, and Sections 

11.0 and 12.0, EPA determined that the costs of Option 2 are not economically achievable for 

existing indirect dischargers in the MFJS Subcategory. EPA estimates that compliance with 

PSES based on the Option 2 technology will result in the closure of 46 percent of the existing 

indirect dischargers in this subcategory (589 of 1,270 existing MFJS indirect dischargers), which 

EPA considers to be too high. EPA has determined that Option 2 technology is not the best 

available technology economically achievable for existing indirect dischargers in the MFJS 

Subcategory. Therefore, EPA is not establishing PSES for this subcategory based on the Option 2 

technology. 

As discussed in the January 2001 proposal (66 FR 551) and June 2002 NODA (67 

FR 38801), EPA also considered a number of alternative options whose economic impacts would 

be less costly than Option 2 technology. These options potentially have compliance costs more 

closely aligned with toxic pollutant reductions. EPA considered the following alternative options 

for the final rule: 

� Option A: No change in current regulation; 

� Option B: Option 2 with a higher low-flow exclusion; 

� Option C: Upgrading facilities currently covered by Part 413 to meet the 

PSES of Part 433 (“413 to 433 Upgrade Option” described in Section 

9.2.5); and 

� Option D: Pollution prevention option (see 66 FR 551). 

All facilities in the MFJS Subcategory are currently subject to Part 413, Part 433 or both. 

As discussed in the NODA, preamble to the final rule, and Sections 11.0 and 12.0, 

based on comments, EPA has revised its methodology for estimating compliance costs and 

pollutant loadings for Option 2, low-flow exclusions (Option B), and the “upgrade” option 

(Option C) previously described. Using information from this revised analysis, EPA concludes 

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9.0 - Technology Options 

that neither of these alternative options (Options B or C) are economically achievable. EPA 

rejected Options B and C because more than 10 percent of existing indirect dischargers not 

covered by Part 433 close at the upgrade option. 

EPA also solicited comment in the January 2001 proposal on a pollution 

prevention alternative for indirect dischargers in this subcategory (Option D). Commentors 

supported Option D and stated that the pollution prevention practices identified by EPA in the 

January 2001 proposal represent environmentally sound practices for the metal finishing 

industry. The commentors also stated that Option D should, however, be implemented on a 

voluntary basis similar to the National Metal Finishing Strategic Goals Program (see 66 FR 511). 

Control authorities also commented that Option D may increase their administrative burden 

because of additional review of facility operations and compliance with the approved pollution 

prevention plan, and enforcement of Option D may be more difficult than other options 

considered. EPA is not promulgating Option D for facilities in the MFJS Subcategory for the 

final rule due to the increased administrative burden on pretreatment control authorities and 

potential problems enforcing Option D. Section 8.0 describes many of the pollution prevention 

practices that were considered for Option D. These pollution prevention practices may be useful 

in helping facilities lower operating costs, improve environmental performance, and foster other 

important benefits. 

EPA is not establishing PSES for existing indirect dischargers in the MFJS 

Subcategory. Wastewater discharges to POTWs from facilities in this subcategory will remain 

regulated by General Pretreatment Standards (Part 403), and Parts 413 and/or 433, as applicable. 

EPA also notes that facilities regulated by Parts 413 and/or 433 PSES must comply with Part 433 

PSNS if the changes to their facilities are determined to make them new sources. 

9.3.4 PSNS 

EPA proposed to establish PSNS for indirect dischargers in the MFJS 

Subcategory based on the Option 4 technology. Option 4 technology is similar to Option 2 

(including Option 2 flow control and pollution prevention) but includes oils removal using 

ultrafiltration and solids separation by a microfilter (instead of a clarifier). As explained in 

Section 9.2.4, EPA concluded its database is insufficient to support a determination that the 

Option 4 standards are technically achievable. Consequently, EPA rejected Option 4 technology 

as the basis for PSNS in the MFJS Subcategory. 

For the final rule, EPA evaluated setting MFJS PSNS based on the Option 2 

technology and assessed the financial burden to new MFJS indirect dischargers. Specifically, 

EPA's ‘barrier-to-entry' analysis identified whether MFJS PSNS based on the Option 2 

technology would pose sufficient financial burden on new MFJS facilities to constitute a material 

barrier to entry into the MP&M Point Source Category. 

EPA projects a barrier to entry for MFJS PSNS based on the Option 2 technology 

because 8 percent of MFJS indirect dischargers have after-tax compliance costs between 1 to 3 

9-17

9.0 - Technology Options 

percent of revenue, 5 percent have after-tax compliance costs between 3 to 5 percent of revenue, 

and 6 percent have after-tax compliance costs greater than 5 percent of revenue. Consequently, 

EPA rejected Option 2 technology as the basis for PSNS in the MFJS Subcategory, and is not 

revising PSNS for new MFJS indirect dischargers. Wastewater discharges to POTWs from 

facilities in this subcategory will remain regulated by local limits, General Pretreatment 

Standards (Part 403), and Part 433, as applicable. See Section 11.0 for a description of how these 

new source compliance costs were developed and Chapter 9 of the EEBA for a description of the 

framework EPA used for the barrier-to-entry analysis and general discussion of the results. 

Non-Chromium Anodizing Subcategory 

EPA is not revising limitations or standards for any facilities that would have been 

subject to this subcategory. Such facilities will continue to be regulated by the General 

Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, as 

applicable. 

9.4.1 BPT, BCT, and BAT 

As previously discussed, after publication of the June 2002 NODA, EPA 

conducted another review of all Non-Chromium Anodizing (NCA) facilities in the MP&M 

survey database to determine the destination of discharged wastewater (i.e., either directly to 

surface waters or indirectly to POTWs or both) and the applicability of the final rule to 

discharged wastewaters. As a result of this review, EPA did not identify any NCA direct 

discharging facilities or NCA facilities that do not discharge wastewater (i.e., zero discharge or 

contract haulers) or do not use process water (dry facilities) in its rulemaking record. All of the 

NCA facilities in EPA’s database are indirect dischargers. Therefore, EPA cannot evaluate 

treatment systems at direct dischargers. As a result, EPA transferred cost and pollutant loading 

data from the best performing indirect facilities in order to evaluate direct discharging limitations 

in this subcategory. 

EPA evaluated several technology options for direct dischargers for the NCA 

Subcategory, whose unit operations primarily generate metal-bearing wastewater, but may also 

generate some oily wastewater. These include Options 1, 2, 2S, 3, and 4, which are described in 

detail in Section 9.2.1. As discussed in Section 9.2.1, EPA dropped Options 1, 2S, 3, and 4 from 

further consideration. Therefore, for the final rule, EPA considered only Option 2 as the basis for 

limitations for the NCA Subcategory. See Sections 11.0 and 12.0 for the final estimated 

compliance costs and pollutant loadings for Option 2. 

In 2001, EPA proposed to establish BPT/BCT/BAT limitations for direct 

dischargers in the NCA Subcategory based on the Option 2 technology. EPA evaluated the cost 

of effluent reductions, quantity of pollutant reductions, and the economic achievability of 

compliance with BPT/BCT/BAT limitations based on the Option 2 technology. Based on the 

revisions and corrections to the EPA Costs & Loadings Model discussed in the NODA, preamble 

to the final rule, and Sections 11.0 and 12.0, the costs of the Option 2 technology were 

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9.4 
9.0 - Technology Options 

disproportionate to the projected toxic pollutants reductions (cost-effectiveness values (in 1981$) 

in excess of $1,925/PE). 

EPA decided not to establish BPT/BAT limitations based on the Option 2 

technology for the NCA Subcategory for following reasons: (1) EPA identified no NCA direct 

dischargers, and (2) the costs of Option 2 are disproportionate to the estimated toxic pollutant 

reductions (i.e., $1,925/PE). EPA concludes that for existing direct dischargers in the NCA 

Subcategory, Option 2 is not the best practicable control technology, best conventional pollutant 

control technology, or best available technology economically achievable. EPA has decided not 

to establish new BPT, BCT, or BAT limitations for existing NCA direct dischargers based on the 

Option 2 technology. Although, EPA identified no NCA direct dischargers through its survey 

efforts, if such facilities do exist, they would be subject to Part 433. 

9.4.2 NSPS 

EPA proposed to establish NSPS for direct dischargers in the NCA Subcategory 

based on the Option 2 technology. For the final rule, EPA evaluated setting NCA NSPS based 

on the Option 2 technology and assessed the financial burden to new NCA direct dischargers. 

Specifically, EPA's ‘barrier-to-entry' analysis identified whether NCA NSPS based on the Option 

2 technology would pose sufficient financial burden on new NCA facilities to constitute a 

material barrier to entry into the MP&M Point Source Category. 

EPA projects a barrier to entry for NCA NSPS based on the Option 2 technology 

because approximately 26 percent of NCA direct dischargers have new source compliance costs 

that are between 3 percent and 5 percent of revenue. Consequently, EPA rejected Option 2 

technology as the basis for NSPS in the NCA Subcategory. EPA has selected “no further 

regulation” for new NCA direct dischargers and is not revising NSPS for new NCA direct 

dischargers, which will remain subject to Part 433. See Section 11.0 for a description of how 

these new source compliance costs were developed and Chapter 9 of the EEBA for a description 

of the framework EPA used for the barrier-to-entry analysis and general discussion of the results. 

9.4.3 PSES and PSNS 

EPA proposed “no further regulation” for existing and new indirect dischargers in 

the NCA Subcategory. EPA based this decision on the economic impacts to indirect dischargers 

associated with Option 2 and the small quantity of toxic pollutants discharged by facilities in this 

subcategory, even after a economically achievable flow cutoff is applied (see 66 FR 467). For 

the reasons set out in the 2001 proposal, EPA has decided not to establish new regulations and is 

not establishing PSES or PSNS in the NCA Subcategory. These facilities remain subject to Parts 

413 or 433, or both, as applicable. EPA also notes that facilities regulated by Parts 413 and/or 

433 PSES must comply with Part 433 PSNS if the changes to their facilities are determined to 

make them new sources. 

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9.0 - Technology Options 

9.5 Printed Wiring Board Subcategory 

EPA is not revising any limitations or standards for facilities that would have been 

subject to this subcategory. Such facilities will continue to be regulated by the General 

Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, as 

applicable. 

9.5.1 BPT, BCT, and BAT 

EPA evaluated several technology options for direct dischargers for the Printed 

Wiring Board (PWB) Subcategory, whose unit operations primarily generate metal-bearing 

wastewater, but may also generate some oily wastewater. These include Options 1, 2, 2S, 3, and 

4, which are described in detail in Section 9.2.1. As discussed in Section 9.2.1, EPA dropped 

Options 1, 2S, 3, and 4 from further consideration. Therefore, for the final rule, EPA considered 

only Option 2 as the basis for limitations for the PWB Subcategory. See Sections 11.0 and 12.0 

for the final estimated compliance costs and pollutant loadings for Option 2. 

EPA proposed to establish BPT/BCT/BAT for direct dischargers in the PWB 

Subcategory based on the Option 2 technology (see Section 9.2.1 for a description of Option 2). 

EPA evaluated the cost of effluent reductions, pollutant reductions, and the economic 

achievability of compliance with BPT/BCT/BAT limitations based on the Option 2 technology. 

Based on MP&M survey information, EPA estimates that compliance with 

BPT/BCT/BAT limitations based on the Option 2 technology results in no closures of the 

existing eight direct dischargers in the PWB Subcategory. However, EPA decided not to 

establish BPT/BAT limitations based on the Option 2 technology for the PWB Subcategory for 

the following reasons: (1) EPA identified only eight existing PWB direct dischargers and all of 

these PWB direct dischargers are currently regulated by existing effluent guidelines (Part 433), 

and (2) the costs of Option 2 are disproportionate to the estimated toxic pollutant reductions. 

EPA estimates compliance costs of $0.3 million (2001$ dollars) with only 186 toxic 

pound-equivalents (PE) being removed. This equates to a cost-effectiveness value (in 1981$) of 

approximately $900/PE. EPA concludes that, for existing direct dischargers in the PWB 

Subcategory, Option 2 is not the best practicable control technology, best conventional pollutant 

control technology, or best available technology economically achievable. EPA has decided not 

to establish new BPT, BCT, or BAT limitations for existing PWB direct dischargers based on the 

Option 2 technology; these discharges will remain subject to Part 433. 

9.5.2 NSPS 

EPA proposed to establish NSPS for new direct dischargers in the PWB 

Subcategory based on the Option 4 technology. Option 4 technology is similar to Option 2 

(including Option 2 flow control and pollution prevention) but includes oils removal using 

ultrafiltration and solids separation by a microfilter (instead of a clarifier). As explained in 

Section 9.2.4, EPA concluded that its database is insufficient to support a determination that the 

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9.0 - Technology Options 

Option 4 standards are technically achievable. Consequently, EPA rejected Option 4 technology 

as the basis for NSPS in the PWB Subcategory. 

For the final rule, EPA evaluated setting PWB NSPS based on the Option 2 

technology. EPA reviewed its database for establishing PWB NSPS based on the Option 2 

technology as commentors indicated the proposed standards were not technically achievable. In 

response to these comments, EPA reviewed all the information currently available on PWB 

facilities using the Option 2 technology basis. EPA now concludes that the PWB’s Option 2 

database can only be used to establish limitations for copper, nickel, and tin. In order to assess 

the difference between current NSPS requirements (from Part 433) for PWB facilities and those 

under consideration in the final rule, EPA estimated the incremental quantities of copper, nickel, 

and tin that would be reduced if a new PWB facility were required to meet NSPS based on the 

Option 2 technology rather than NSPS based on Part 433. EPA analysis shows minimal amounts 

of pollutant reductions based on more stringent requirements on copper, nickel, and tin. 

Consequently, EPA rejected Option 2 technology as the basis for NSPS in the 

PWB Subcategory based on the small incremental quantity of toxic pollutants that would be 

reduced in relation to existing requirements. EPA is not establishing NSPS or revising existing 

NSPS for new PWB direct dischargers. Wastewater discharges from these facilities in this 

subcategory will remain regulated by permit limits and Part 433 as applicable. See Section 11.0 

for a description of how these new source compliance costs were developed and Chapter 9 of the 

EEBA for a description of the framework EPA used for the barrier-to-entry analysis and general 

discussion of the results. 

9.5.3 PSES 

EPA evaluated several technology options for indirect dischargers for the PWB 

Subcategory, whose unit operations primarily generate metal-bearing wastewater, but may also 

generate some oily wastewater. These include the same option as evaluated for BAT (i.e., 

Option 2 as described in Section 9.2.1), as well as several alternative options described below. 

EPA did not further evaluate Options 1, 2S, 3, and 4 for the final rule for the same reasons as 

explained for BPT above. See Sections 11.0 and 12.0 for the final estimated compliance costs 

and pollutant loadings for Option 2 and the alternative options considered for the final rule. 

EPA proposed to establish PSES for existing indirect dischargers in the PWB 

Subcategory based on the Option 2 technology. Based on the revisions and corrections to the 

EPA Costs & Loadings Model discussed in the NODA, preamble to the final rule, and Sections 

11.0 and 12.0, EPA rejected promulgating PSES for existing indirect dischargers in the PWB 

Subcategory based on the Option 2 technology for the following reasons: (1) all PWB indirect 

dischargers are currently regulated by existing effluent guidelines (Parts 413 or 433 or both, as 

applicable); (2) EPA estimates that compliance with PSES based on the Option 2 technology will 

result in the closure of 6.5 percent of the existing indirect dischargers in this subcategory (55 of 

840 existing PWB indirect dischargers); and (3) EPA determined that the toxic pollutant 

reductions are very expensive per pound removed (the cost-effectiveness value (in 1981$) is 

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9.0 - Technology Options 

$455/PE). EPA has determined that Option 2 technology is not the best available technology 

economically achievable for existing indirect dischargers in the PWB Subcategory, and therefore 

is not establishing PWB PSES based on the Option 2 technology. 

As discussed in the June 2002 NODA (see 67 FR 38802), EPA also considered a 

number of alternative options whose economic impacts would be less costly than Option 2 

technology. These options potentially have compliance costs more closely aligned with toxic 

pollutant reductions. EPA considered the following alternative options for the final rule: 

� Option A: No change in current regulation; 

� Option B: Option 2 with a higher low-flow exclusion; and 

� Option C: Upgrading facilities currently covered by Part 413 to the PSES 

of Part 433 (“413 to 433 Upgrade Option”). 

EPA notes that all facilities in the PWB Subcategory are currently subject to Part 

413, Part 433, or both. 

As discussed in the NODA, preamble to the final rule, and Sections 11.0 and 12.0, 

based on comments, EPA has revised its methodology for estimating compliance costs and 

pollutant loadings for Option 2, higher low-flow exclusions (Option B), and the “upgrade” option 

(Options C) previously described. Using information from this revised analysis, EPA rejected 

Options B and C because: (1) more than 10 percent of existing indirect dischargers not covered 

by Part 433 close at the upgrade option; or (2) the incremental compliance costs of the upgrade 

options were too great in terms of toxic removals (cost-effectiveness values (in 1981$) in excess 

of $833/PE). Therefore, EPA is not revising PSES for existing indirect dischargers in the PWB 

Subcategory. Wastewater discharges to POTWs from facilities in this subcategory will remain 

regulated by General Pretreatment Standards (Part 403) and Parts 413 and/or 433, as applicable. 

EPA also notes that facilities regulated by Parts 413 and/or 433 PSES must comply with Part 433 

PSNS if the changes to their facilities are determined to make them new sources. 

9.5.4 PSNS 

EPA proposed to establish PSNS for indirect dischargers in the PWB Subcategory 

based on the Option 4 technology. Option 4 technology is similar to Option 2 (including Option 

2 flow control and pollution prevention) but includes oils removal using ultrafiltration and solids 

separation by a microfilter (instead of a clarifier). As explained in Section 9.2.4, EPA concluded 

that its database is insufficient to support a determination that the Option 4 standards are 

technically achievable. Consequently, EPA rejected Option 4 technology as the basis for PSNS 

in the PWB Subcategory. 

For the final rule, EPA evaluated setting PWB PSNS based on the Option 2 

technology and assessed the financial burden to new PWB indirect dischargers. Specifically, 

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9.0 - Technology Options 

EPA's ‘barrier-to-entry' analysis identified whether PWB PSNS based on the Option 2 

technology would pose sufficient financial burden on new PWB facilities to constitute a material 

barrier to entry into the MP&M Point Source Category. 

EPA projects a barrier to entry for PWB PSNS based on the Option 2 technology 

because 3 percent of PWB indirect dischargers have after-tax compliance costs between 1 to 3 

percent of revenue and 4 percent have after-tax compliance costs greater than 5 percent of 

revenue. Consequently, EPA rejected Option 2 technology as the basis for PSNS in the PWB 

Subcategory. EPA has selected “no further regulation” for new PWB indirect dischargers and is 

not revising PSNS for new PWB indirect dischargers. Wastewater discharges to POTWs from 

facilities in this subcategory will remain regulated by local limits, General Pretreatment 

Standards (Part 403), and Part 433, as applicable. See Section 11.0 for a description of how 

these new source compliance costs were developed and Chapter 9 of the EEBA for a description 

of the framework EPA used for the barrier-to-entry analysis and general discussion of the results. 

Steel Forming and Finishing Subcategory 

EPA is not revising limitations or standards for any facilities that would have been 

subject to this subcategory. Such facilities will continue to be regulated by the General 

Pretreatment Standards (Part 403), local limits, permit limits, and Iron and Steel effluent 

limitations guidelines (Part 420), as applicable. 

9.6.1 BPT, BCT, and BAT 

EPA evaluated several technology options for direct dischargers for the Steel 

Forming and Finishing (SFF) Subcategory, whose unit operations primarily generate metalbearing wastewater, but may also generate some oily wastewater. These include Options 1, 2, 

2S, 3, and 4, which are described in detail in Section 9.2.1. As discussed Section 9.2.1, EPA 

dropped Options 1, 2S, 3, and 4 from further consideration. Therefore, for the final rule, EPA 

considered only Option 2 as the basis for limitations for the SFF Subcategory. See Sections 11.0 

and 12.0 for the final estimated compliance costs and pollutant loadings for Option 2. 

EPA proposed to establish BPT/BCT/BAT for existing direct dischargers in the 

SFF Subcategory based on the Option 2 technology (see Section 9.2.1 for a description of Option 

2). For the final rule, EPA evaluated the cost of effluent reductions, pollutant reductions, and the 

economic achievability of compliance with BPT/BCT/BAT limitations based on the Option 2 

technology. Based on the revisions and corrections to the EPA Costs & Loadings Model 

discussed in the NODA, preamble to the final rule, and Sections 11.0 and 12.0, EPA determined 

that the compliance costs of Option 2 are not economically achievable. EPA estimates that 

compliance with BPT/BCT/BAT limitations based on the Option 2 technology will result in the 

closure of 17 percent of the existing direct dischargers in this subcategory (7 of 41 existing SFF 

direct dischargers). EPA concludes that, for existing direct dischargers in the SFF Subcategory, 

Option 2 is not the best practicable control technology, best conventional pollutant control 

technology, or best available technology economically achievable, and therefore, EPA is not 

9-23


9.6 
9.0 - Technology Options 

establishing new BPT, BCT, or BAT limitations for existing SFF direct dischargers based on the 

Option 2 technology. These facilities will remain subject to Part 420. 

9.6.2 NSPS 

EPA proposed to establish NSPS for new direct dischargers in the SFF 

Subcategory based on the Option 4 technology. Option 4 technology is similar to Option 2 

(including Option 2 flow control and pollution prevention) but includes oils removal using 

ultrafiltration and solids separation by a microfilter (instead of a clarifier). As explained in 

Section 9.2.4, EPA concluded that its database is insufficient to support a determination that the 

Option 4 standards are technically achievable. Consequently, EPA rejected Option 4 technology 

as the basis for NSPS in the SFF Subcategory. EPA has selected “no further regulation” for new 

SFF direct dischargers and is not revising NSPS for new SFF direct dischargers, which will 

remain subject to Part 420. 

9.6.3 PSES 

EPA evaluated several technology options for indirect dischargers for the Steel 

Forming and Finishing Subcategory, whose unit operations primarily generate metal-bearing 

wastewater, but may also generate some oily wastewater. For the final rule, EPA considered the 

same option as evaluated for BAT (i.e., Option 2). EPA did not further evaluate Options 1, 2S, 

3, and 4 for the final rule for the same reasons as explained for BPT above. See the Development 

Document for the Proposed Effluent Limitations Guidelines and Standards for the Metal 

Products & Machinery Point Source Category (EPA 821-B-00-005) for the final estimated 

compliance costs and pollutant loadings for Option 2. 

EPA proposed to establish PSES for existing indirect dischargers in the SFF 

Subcategory based on the Option 2 technology. Based on the revisions and corrections to the 

EPA Costs & Loadings Model discussed in the NODA, preamble to the final rule, and Sections 

11.0 and 12.0, EPA estimates that compliance with PSES based on the Option 2 technology will 

result in the closure of 9 percent of the existing indirect dischargers in this subcategory (10 of 

112 existing SFF indirect dischargers). 

EPA has determined that Option 2 technology is not the best available technology 

economically achievable for existing indirect dischargers in the SFF Subcategory, and therefore 

EPA is not revising PSES for this subcategory based on the Option 2 technology. Wastewater 

discharges to POTWs from these facilities will remain regulated by General Pretreatment 

Standards (Part 403) and Part 420. 

9.6.4 PSNS 

EPA proposed to establish PSNS for indirect dischargers in the SFF Subcategory 

based on the Option 4 technology. Option 4 technology is similar to Option 2 (including Option 

2 flow control and pollution prevention) but includes oils removal using ultrafiltration and solids 

9-24

9.0 - Technology Options 

separation by a microfilter (instead of a clarifier). As explained in Section 9.2.4, EPA concluded 

its database is insufficient to support a determination that the Option 4 standards are technically 

achievable. Consequently, EPA rejected Option 4 technology as the basis for PSNS in the SFF 

Subcategory. EPA has selected “no further regulation” for new SFF indirect dischargers and is 

not revising PSNS for new SFF indirect dischargers; these facilities will remain subject to Part 

420. 

Oily Wastes Subcategory 

EPA is promulgating limitations and standards for existing and new direct 

dischargers in the Oily Wastes Subcategory based on the proposed Option 6 technology (see 

Section 9.7.1). EPA is not promulgating pretreatment standards for existing or new indirect 

dischargers in this subcategory. 

9.7.1 BPT 

EPA evaluated several technology options for the direct dischargers in the Oily 

Wastes Subcategory. Each of these options is discussed below. As discussed in Section 6.0, 

EPA defines the Oily Wastes Subcategory as those facilities that only discharge wastewater from 

one or more oily operations (see Table 6-2 and 40 CFR 438.2(f)). 

Option 5 

Option 5 consists of end-of-pipe chemical emulsion breaking followed by gravity 

separation using an oil/water separator. EPA performed sampling episodes at several facilities in 

the Oily Wastes Subcategory that used chemical emulsion breaking followed by gravity flotation 

and oil skimming. These systems typically achieved a 96-percent removal of oil and grease. 

Breaking the oil/water emulsion requires adding treatment chemicals such as acid, alum, and/or 

polymers to change the emulsified oils or cutting fluids from hydrophilic colloids to aggregate 

hydrophobic particles. The aggregated oil particles, with a density less than water, can be 

removed by gravity flotation in a coalescing plate oil/water separator. Option 5 also includes 

contract hauling of organic solvent-bearing wastewaters instead of discharge. 

Option 6 

Option 6 consists of the technologies in Option 5 plus the following in-process 

flow control and pollution prevention technologies, which allow for recovery and reuse of 

materials along with water conservation: 

� Two-stage countercurrent cascade rinsing for all flowing rinses; 

� Centrifugation and recycling of painting water curtains; and 

9-25


9.7 
9.0 - Technology Options 

� Centrifugation, pasteurization, and recycling of water-soluble machining 

coolants. 

Option 7 

Option 7 consists of end-of-pipe ultrafiltration, as well as contract hauling of 

organic solvent-bearing wastewater instead of discharge. Sampling episode data determined that, 

on average, ultrafilters will remove greater than 99 percent of all oil and grease in the influent 

stream. 

Option 8 

Option 8 consists of the Option 7 technology (ultrafiltration) plus the pollution 

prevention and water conservation alternatives described in Option 6. 

Option Selection 

As discussed in the 2001 proposal (66 FR 451), EPA dropped Options 5 and 7 

from further consideration because Options 6 and 8, respectively, cost less and provided greater 

pollutant removals. Subsequent to proposal, EPA also dropped Option 8 from further 

consideration for the final rule because of its increased cost and lack of significant additional 

pollutant removals beyond Option 6. Therefore, for the final rule, EPA considered only Option 6 

as the basis for limitations for the Oily Wastes Subcategory. See Sections 11.0 and 12.0 for the 

final estimated compliance costs and pollutant loadings for Option 6. 

EPA is establishing BPT pH limitations and daily maximum limitations for two 

pollutants, oil and grease as hexane extractable material (oil and grease (as HEM)) and total 

suspended solids (TSS), for direct dischargers in the Oily Wastes Subcategory based on the 

proposed technology option (Option 6). Option 6 technology includes the following treatment 

measures: (1) in-process flow control and pollution prevention; and (2) oil/water separation by 

chemical emulsion breaking and skimming (see above for additional details on the Option 6 

technology). 

The Agency concluded that the Option 6 treatment technology represents the best 

practicable control technology currently available and should be the basis for the BPT Oily 

Wastes limitations for the following reasons. First, this technology is available and readily 

applicable to all facilities in the Oily Wastes Subcategory. Approximately 42 percent of the 

direct dischargers in the Oily Wastes Subcategory currently use the Option 6 technology. 

Second, the cost of compliance with these limitations in relation to the effluent reduction benefits 

is not wholly disproportionate. None of these wastewater discharges are currently subject to 

national effluent limitations guidelines and the final rule will control wastewater discharges from 

a significant number (2,382) of facilities. 

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9.0 - Technology Options 

EPA estimates that compliance with BPT limitations based on Option 6 

technology will result in no closures of the existing direct dischargers in the Oily Wastes 

Subcategory. Moreover, the adoption of this level of control will significantly reduce the amount 

of pollutants discharged into the environment by facilities in this subcategory. For facilities in 

the Oily Wastes Subcategory at Option 6, EPA estimates an annual compliance cost of $13.8 

million (pre-tax, 2001$) and 480,325 pounds of conventional pollutants removed from current 

discharges into the Nation’s waters at a cost of $28.73/pound-pollutant removed (2001$). EPA 

has, therefore, determined that the total cost of effluent reductions as a result of using the Option 

6 technology are reasonable in relation to the effluent reduction benefits. (In estimating the 

pounds of pollutant removed by implementing Option 6 technology for direct dischargers in the 

Oily Wastes Subcategory, EPA used the sum of oil and grease (as HEM) and TSS pounds 

removed to avoid any significant double counting of pollutants). 

The 2001 proposal also contains detailed discussions explaining why EPA 

rejected BPT limitations based on other BPT technology options (see 66 FR 457). The 

information in the record for the final rule provides no basis for EPA to change this conclusion. 

In the 2001 proposal, EPA proposed to regulate sulfide in addition to pH, oil and 

grease (as HEM), and TSS. In the final rule, EPA has not established a sulfide limitation because 

it may serve as a treatment chemical (see Section 7.0). EPA also proposed three alternatives to 

control discharges of toxic organics in MP&M process wastewaters: (1) meet a numerical limit 

for the total sum of a list of specified organic pollutants (similar to the Total Toxic Organic 

(TTO) parameter used in the Metal Finishing effluent limitations guidelines); (2) meet a 

numerical limit for total organic carbon (TOC) as an indicator parameter; or (3) develop and 

certify the implementation of an organic chemicals management plan. EPA evaluated the 

analytical wastewater and treatment technology data from Oily Wastes facilities and concluded it 

should not establish a separate indicator parameter or control mechanism for toxic organics. 

Optimizing the separation of oil and grease from wastewater using the Option 6 technology will 

similarly optimize the removal of toxic organic pollutants amenable to this treatment technology. 

Consequently, EPA is effectively controlling toxic organics and other priority and 

nonconventional pollutant discharges in Oily Wastes Subcategory process wastewaters by 

regulating oil and grease (as HEM). 

In its analyses, EPA estimated that facilities will monitor once per month for oil 

and grease (as HEM) and TSS. EPA expects that 12 data points for each pollutant per year will 

yield a meaningful basis for establishing compliance with the promulgated limitations through 

long-term trends and short-term variability in oil and grease (as HEM) and TSS pollutant 

discharge loading patterns. 

Although EPA is not changing the technology basis from that proposed, EPA is 

revising all of the proposed Oily Wastes Subcategory BPT limitations. This is a result of a 

recalculation of the limitations after EPA revised the data sets used to calculate the promulgated 

limitations to reflect changes including corrections and additional data (see 67 FR 38754). 

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9.0 - Technology Options 

9.7.2 BCT 

In deciding whether to adopt more stringent limitations for BCT than BPT, EPA 

considered whether there are technologies that achieve greater removals of conventional 

pollutants than adopted for BPT, and whether those technologies are cost-reasonable under the 

standards established by the CWA. EPA generally refers to the decision criteria as the “BCT cost 

test.” EPA is promulgating effluent limitations for conventional parameters (e.g., pH, TSS, oil 

and grease) equivalent to BPT for this subcategory because it identified no technologies that can 

achieve greater removals of conventional pollutants than the selected BPT technology basis that 

also pass the BCT cost test. EPA evaluated the addition of ultrafiltration technology to the BPT 

technology basis as a means to obtain further oil and grease reductions. However, this 

technology option failed the BCT cost test. For a more detailed description of the BCT cost test 

and details on EPA’s analysis, see Chapter 4 of the EEBA. 

9.7.3 BAT 

EPA proposed to control toxic and nonconventional pollutants by establishing 

BAT limitations based on Option 6 technology. As described in Section 9.7.1, EPA has decided 

not to establish BAT toxic and nonconventional limitations based on the Option 6 technology. 

While the BPT limitations are cost reasonable, the additional costs associated with compliance 

with Option 6-generated BAT limitations are not warranted. EPA has determined that these 

costs, primarily monitoring costs, are not warranted in view of the small quantity of additional 

effluent reduction (if any) the BAT limitations would produce. As explained above, EPA has 

determined that the BPT limitation on oil and grease (as HEM) will effectively control toxic and 

nonconventional discharges in Oily Wastes Subcategory process wastewaters. EPA has not 

identified any more stringent economically achievable treatment technology option beyond BPT 

technology (Option 6) that it considered to represent BAT level of control applicable to Oily 

Wastes Subcategory facilities. 

For the reasons explained above, EPA has concluded that it should not establish 

BAT limitations for specific pollutant parameters for Oily Waste operations. EPA notes that 

permit writers retain the authority to establish, on a case-by-case basis under Section 

301(b)(1)(C) of the CWA, toxic effluent limitations that are necessary to meet state water quality 

standards. 

9.7.4 NSPS 

EPA is promulgating NSPS that would control pH and the same conventional 

pollutants controlled at the BPT and BCT levels. The selected technology basis for NSPS for 

this subcategory for the final rule is Option 6. This is unchanged from the proposal. EPA 

projects no barrier to entry for new source direct dischargers associated with Option 6 because: 

(1) Option 6 technology is currently used at existing direct dischargers (i.e., Option 6 technology 

is technically available), and (2) there is no barrier to entry for new sources. 

9-28

9.0 - Technology Options 

EPA evaluated the economic impacts for existing direct dischargers associated 

with compliance with limitations based on Option 6 and found Option 6 to be economically 

achievable (no closures projected). EPA expects compliance costs to be lower for new sources 

as new sources can use Option 6 technology without incurring retrofitting costs (as is required for 

some existing sources). Additionally, EPA projects no barrier to entry for Oily Wastes NSPS 

based on the Option 6 technology because approximately 97 percent of Oily Wastes direct 

dischargers have after-tax compliance costs less than 1 percent of revenue and 3 percent have 

after-tax compliance costs between 1 to 3 percent of revenue. 

In addition, EPA also evaluated and rejected more stringent technology options 

for Oily Wastes NSPS (i.e., Options 8 and 10). EPA reviewed its database for the Option 8 and 

10 technologies and found that the database for Option 8 and 10 technologies is insufficient (i.e., 

no available data) or the costs are not commensurate with the pollutant removals (see 66 FR 

457). 

Consequently, EPA selected Option 6 technology as the basis for NSPS in the 

Oily Wastes Subcategory. See Section 11.0 for a description of how these new source 

compliance costs were developed and Chapter 9 of the EEBA for a description of the framework 

EPA used for the barrier-to-entry analysis and general discussion of the results. 

In addition, EPA also evaluated and rejected more stringent technology options 

for Oily Wastes NSPS (i.e., Options 8 and 10). EPA reviewed its database for the Option 8 and 

10 technologies and found no available data for Option 8 and 10 technologies. Since EPA's 

database did not contain Option 10 treatability data from Oily Wastes facilities, EPA considered 

transferring limitations for Option 10 from the Shipbuilding Dry Dock or Railroad Line 

Maintenance Subcategories. EPA ultimately rejected this approach, however, because influent 

wastewaters in the Shipbuilding Dry Dock and Railroad Line Maintenance Subcategories are 

generally less concentrated and contain less pollutants than wastewaters discharged by Oily 

Wastes facilities. 

9.7.5 PSES 

EPA evaluated the same technology options for indirect dischargers in the Oily 

Wastes Subcategory as for direct dischargers in the subcategory. For the final rule, EPA 

considered the same option as evaluated for BAT (i.e., Option 6). EPA did not further evaluate 

Options 5, 7, and 8 for the final rule for the same reasons as explained for BPT above. See 

Sections 11.0 and 12.0 for the final estimated compliance costs and pollutant loadings for Option 

6. 

EPA proposed to establish PSES for existing indirect dischargers in the Oily 

Wastes Subcategory based on the Option 6 technology (i.e., the same technology basis that is 

being promulgated for BPT/BCT/NSPS for this subcategory) with a “low-flow” exclusion of 2 

MGY to reduce economic impacts on small businesses and administrative burden for control 

authorities. Based on the revisions and corrections to the EPA Costs & Loadings Model 

9-29

9.0 - Technology Options 

discussed in the NODA, preamble to the final rule, and Sections 11.0 and 12.0, and previously 

discussed, EPA determined that the toxic pollutant reductions are very expensive in dollars per 

toxic pounds removed. The cost-effectiveness value (in 1981$) for Option 6 for indirect 

dischargers in the Oily Wastes Subcategory is in excess of $3,500/PE removed. This suggests 

that the technology is not truly “available.” EPA has determined that Option 6 technology with a 

2-MGY low-flow cutoff is not the best available technology economically achievable for existing 

indirect dischargers in the Oily Wastes Subcategory. Therefore, EPA is not establishing PSES 

for this subcategory based on Option 6 technology with a 2-MGY low-flow cutoff. 

As discussed in the June 2002 NODA (67 FR 38804), EPA also considered 

alternative options for which economic impacts could be less costly than Option 6 technology 

with a 2-MGY low-flow cutoff. These options potentially have compliance costs more closely 

aligned with toxic pollutant reductions. EPA considered the following alternative options for the 

final rule: 

� Option A: No regulation; and


� Option B: Option 6 with a higher low-flow exclusion.


As discussed in the NODA, preamble to the final rule, and Sections 11.0 and 12.0, 

based on comments, EPA has revised its methodology for estimating compliance costs and 

pollutant loadings for Option 6 with a higher low-flow exclusion (Option B). Using information 

from this revised analysis, EPA concludes that none of the alternative low-flow exclusions (even 

as high as 6.25 MGY) represented “available technology” because the costs associated with these 

alternatives were not commensurate with the projected toxic pollutants reductions. Therefore, 

EPA is not establishing PSES for existing indirect dischargers in the Oily Wastes Subcategory 

(Option A). Since EPA did not identify another technology basis that was more cost-effective, 

EPA is not promulgating PSES for existing indirect dischargers in the Oily Wastes Subcategory. 

These facilities remain subject to the General Pretreatment Standards (40 CFR 403) and local 

limits, as applicable. 

9.7.6 PSNS 

EPA proposed to establish PSNS for indirect dischargers in the Oily Wastes 

Subcategory based on the Option 6 technology (i.e., the same technology basis that is being 

promulgated for NSPS for this subcategory) with a “low-flow” exclusion of 2 MGY to reduce 

economic impacts on small businesses and reduce administrative burden to POTWs. 

For the final rule, EPA evaluated setting Oily Wastes PSNS based on Option 6 

technology and assessed the financial burden of Oily Wastes PSNS based on Option 6 

technology on new Oily Wastes indirect dischargers. Specifically, EPA's ‘barrier-to-entry' 

analysis identified whether Oily Wastes PSNS based on Option 6 technology would pose 

sufficient financial burden on new Oily Wastes facilities to constitute a material barrier to entry 

into the MP&M Point Source Category. 

9-30

9.0 - Technology Options 

EPA projects a barrier to entry for Oily Waste PSNS based on Option 6 

technology as approximately because 1 percent of Oily Waste indirect dischargers have after-tax 

compliance costs between 1 to 3 percent of revenue and 5 percent have after-tax compliance 

costs between 3 to 5 percent of revenue. Consequently, EPA rejected Option 6 technology as the 

basis for PSNS in the Oily Wastes Subcategory. EPA has selected “no further regulation” for 

new Oily Wastes indirect dischargers and is not revising PSNS for new Oily Wastes indirect 

dischargers. Wastewater discharges to POTWs from facilities in this subcategory will remain 

regulated by local limits and General Pretreatment Standards (Part 403), as applicable. See 

Section 11.0 for a description of how these new source compliance costs were developed and 

Chapter 9 of the EEBA for a description of the framework EPA used for the barrier-to-entry 

analysis and general discussion of the results. 

Railroad Line Maintenance Subcategory 

EPA is not establishing limitations or standards for any facilities that would have 

been subject to this subcategory. Permit writers and control authorities will establish controls 

using BPJ to regulate wastewater discharges from these facilities. 

9.8.1 BPT 

At proposal, EPA evaluated four technology options for the Railroad Line 

Maintenance (RRLM) Subcategory. These included Options 7 and 8, which are described in 

detail in Section 9.7.1, and Options 9 and 10, described below. In addition, for the final rule, 

EPA evaluated Option 6 for this subcategory (see Section 9.7.1). 

Option 9 

Option 9 consists of end-of-pipe chemical emulsion breaking followed by 

dissolved air flotation (DAF) to remove flocculated oils. This treatment train is demonstrated in 

both the Shipbuilding Dry Dock and RRLM Subcategories and effectively removes emulsified 

oils and suspended solids. Option 9 also includes contract hauling of organic solvent-bearing 

wastewater instead of discharge. 

Option 10 

Option 10 consists of the end-of-pipe treatment technologies included in Option 9 

plus in-process flow control and pollution prevention technologies, which allow for recovery and 

reuse of materials along with water conservation. The specific Option 10 in-process technologies 

include: 

� Two-stage countercurrent cascade rinsing for all flowing rinses; 

� Centrifugation and recycling of painting water curtains; and 

9-31


9.8 
9.0 - Technology Options 

� Centrifugation, pasteurization, and recycling of water soluble machining 

coolants. 

Option Selection 

For the final rule, EPA evaluated setting BPT limitations for two pollutants, TSS 

and oil and grease (as HEM), for direct dischargers in the RRLM Subcategory based on a 

different technology basis from that proposed in 2001. EPA proposed Option 10 technology as 

the technology basis for BPT. However, as discussed in the NODA, EPA considered 

promulgating limitations for the final rule based on the Option 6 technology for the RRLM 

Subcategory (see 67 FR 38804). Option 6 technology includes the following: (1) in-process flow 

control and pollution prevention; and (2) oil/water separation by chemical emulsion breaking and 

skimming (see Section 9.7.1 for additional details on the Option 6 technology). 

For the RRLM Subcategory, EPA changed the technology basis considered for the 

final rule based on comments and data submitted by the American Association of Railroads 

(AAR). This organization is a trade association that currently represents all facilities in this 

subcategory. As discussed in the NODA (67 FR 38755), for each RRLM direct discharging 

facility known to them, AAR provided current permit limits, treatment-in-place, and summarized 

information on each facility’s measured monthly average and daily maximum values. AAR also 

provided a year’s worth of long-term monitoring data for each facility (see Section 15.1 of the 

rulemaking record for the AAR surveys). This data shows that, contrary to EPA’s initial findings 

in the 2001 proposal, most RRLM direct dischargers treat their wastewater by chemical emulsion 

breaking/oil skimming (Option 6). Based on this updated information, EPA rejected Option 10 as 

the technology basis for BPT. The 2001 proposal also contains detailed discussions on why EPA 

rejected BPT limitations based on other BPT technology options (see 66 FR 451). The 

information in the rulemaking record provides no basis for EPA to change this conclusion. 

As previously discussed, after publication of the June 2002 NODA, EPA also 

conducted another review of all RRLM facilities in the MP&M survey database to determine the 

destination of discharged wastewater (i.e., either directly to surface waters or indirectly to 

POTWs or both) and the applicability of the final rule to discharged wastewaters. As a result of 

this review, EPA determined that its survey database did not accurately represent direct 

dischargers in this subcategory. Consequently, for the final rule, EPA used the information 

supplied by AAR as a basis for its analyses and conclusions on direct dischargers in this 

subcategory. 

AAR provided information on 27 facilities. EPA reviewed the information on 

each of these facilities to ensure they were direct dischargers, discharged wastewaters resulting 

from operations subject to this final rule, and discharged "process" wastewaters as defined by the 

final rule. As a result of this review, EPA concluded that 18 of the facilities for which AAR 

provided information do not directly discharge wastewaters exclusively from oily operations (see 

Section V.A of the preamble to the final rule). Therefore, EPA's final database consists of data 

for nine direct discharging RRLM facilities. EPA considered promulgating BPT limitations for 

9-32

9.0 - Technology Options 

these nine direct discharging RRLM facilities based on the Option 6 technology. The Agency 

made the following conclusions during its evaluation of Option 6 for this subcategory. 

First, this technology is readily applicable to all facilities in the RRLM 

Subcategory. All direct dischargers in the RRLM Subcategory currently use wastewater 

treatment equivalent or better than chemical emulsion breaking/oil skimming (Option 6). 

Second, EPA estimates that compliance with BPT limitations based on Option 6 technology will 

result in no closures of the existing direct dischargers in the RRLM Subcategory. Moreover, 

none of the facilities identified by AAR are small businesses as defined by the Small Business 

Administration (SBA). Third, most of the RRLM facilities identified by AAR have NPDES 

daily maximum permit limitations for oil and grease (as HEM) and TSS as 15 and 45 mg/L, 

respectively. Based on AAR survey information, EPA concludes that these oil and grease (as 

HEM) and TSS daily maximum limits represent the average of the best performances of facilities 

utilizing Option 6 technology. 

EPA evaluated the compliance costs and load reductions associated with 

establishing BPT daily maximum limitations equivalent to 15 and 45 mg/L for oil and grease (as 

HEM) and TSS, respectively. EPA concluded that all of the facilities identified by AAR 

currently meet a daily maximum oil and grease limit of 15 mg/L and most currently monitor once 

per month. Therefore, EPA estimates no pollutant load reductions and minimal incremental 

annualized compliance costs for the monitoring associated with a BPT daily maximum limitation 

equivalent to 15 mg/L for oil and grease (as HEM). For TSS, with the exception of one facility, 

all RRLM facilities identified by AAR currently meet a daily maximum limit of 45 mg/L. For 

this one facility, EPA estimates the TSS pollutant loadings reductions associated with a BPT 

daily maximum limitation equivalent to 45 mg/L to be less than 1 pound of TSS per day. Given 

the fact that the few facilities in this subcategory are already essentially achieving the limitations 

under consideration, EPA has determined that additional national regulation is not warranted. As 

a result of this analysis, EPA concludes that it is more appropriate to address permits limitations 

for this industry on a case-by-case basis and that additional national regulation of direct 

discharges in the RRLM Subcategory at this time is unwarranted. 

9.8.2 BCT 

In deciding whether to adopt more stringent limitations for BCT than BPT, EPA 

considers whether there are technologies that achieve greater removals of conventional pollutants 

than adopted for BPT, and whether those technologies are cost-reasonable under the standards 

established by the CWA. EPA generally refers to the decision criteria as the “BCT cost test.” For 

a more detailed description of the BCT cost test and details of EPA’s analysis, see Chapter 4 of 

the EEBA. 

For the reasons discussed above, EPA is not establishing BCT limitations for the 

RRLM Subcategory. 

9-33

9.0 - Technology Options 

9.8.3 BAT 

As proposed, EPA is not establishing BAT regulations for the RRLM 

Subcategory. EPA did not propose BAT regulations because the Agency concluded that facilities 

in this subcategory discharge very few pounds of toxic pollutants. EPA estimates that six 

facilities discharge 34 PE per year to surface waters, or about 6 PE per year per facility. The 

Agency based the loadings calculations on EPA sampling data, which found very few priority 

toxic pollutants at treatable levels in raw wastewater. EPA has received no data or information 

during the rulemaking that contradicts these conclusions. Therefore, nationally applicable 

regulations for toxic and nonconventional pollutants are unnecessary at this time and direct 

dischargers will remain subject to permit limitations for toxic and nonconventional pollutants 

established on a case-by-case basis using BPJ. 

9.8.4 NSPS 

EPA proposed setting NSPS based on Option 10 technology for this subcategory. 

For the final rule, EPA considered setting RRLM NSPS based on Option 10 technology and 

assessed the financial burden of RRLM NSPS based on Option 10 technology on new RRLM 

direct dischargers. Specifically, EPA’s ‘barrier-to-entry’ analysis identified whether RRLM 

NSPS based on Option 10 technology would pose sufficient financial burden as to constitute a 

material barrier to entry into the MP&M Point Source Category. 

EPA projects no barrier to entry for RRLM NSPS based on Option 10 technology 

because: (1) Option 10 technology is currently used at existing RRLM direct dischargers (i.e., 

Option 10 technology is technically available), and (2) all RRLM direct dischargers have new 

source compliance costs that are less than 1 percent of revenue. However, EPA is not 

promulgating RRLM NSPS based on the Option 10 technology because EPA concludes that it is 

more appropriate to address limitations for this industry on a case-by-case basis and that national 

regulation of direct discharges in the RRLM Subcategory at this time is unwarranted. See 

Section 11.0 for a description of how these new source compliance costs were developed and 

Chapter 9 of the EEBA for a description of the framework EPA used for the barrier-to-entry 

analysis and general discussion of the results. 

9.8.5 PSES and PSNS 

EPA proposed not to establish pretreatment standards for existing and new 

indirect dischargers in the RRLM Subcategory based on the small quantity of toxic pollutants 

discharged to the environment (after POTW treatment) by facilities in this subcategory (i.e., 

approximately 2 PE removed annually per facility (see 66 FR 470-471)). For the same reasons 

set out in the 2001 proposal, EPA is not promulgating pretreatment standards for existing or new 

indirect dischargers in this subcategory. These facilities remain subject to the General 

Pretreatment Standards (40 CFR 403) and local limits. 

9-34

9.0 - Technology Options 

9.9 Shipbuilding Dry Dock Subcategory 

EPA is not establishing limitations or standards for any facilities that would have 

been subject to this subcategory. Permit writers and control authorities will establish controls 

using BPJ to regulate wastewater discharges from these facilities. 

9.9.1 BPT/BCT/BAT/NSPS 

EPA evaluated four technology options for the Shipbuilding Dry Dock (SDD) 

Subcategory. These include Options 7 and 8, which are described in detail in Section 9.7.1, and 

Options 9 and 10, which are described in detail in Section 9.8.1. 

As discussed in the 2001 proposal (66 FR 451), EPA dropped Options 7 and 9 

from further consideration because Options 8 and 10, respectively, cost less and provided greater 

pollutant removals. EPA also evaluated and rejected a more stringent technology option for SDD 

NSPS (i.e., Option 8). EPA reviewed its database for the Option 8 technology and found that no 

available data or possibility of data transfer from the other oily subcategories are available 

because ultrafiltration does not consistently show a better removal than Option 10 to support a 

determination that NSPS based on Option 8 standards are technically achievable. EPA 

concluded that Option 8 does not represent the best practicable control technology. Therefore, 

for the final rule, EPA considered only Option 10 as the basis for limitations for the SDD 

Subcategory. See Sections 11.0 and 12.0 for the final estimated compliance costs and pollutant 

loadings for Option 10. 

At the time of the 2001 proposal, EPA identified six direct discharging SDD 

facilities with multiple discharges. Based on the information in the database at that time, 

discharges from these facilities contained minimal concentrations of toxic organic and metals 

pollutants (<9 PE/facility), but substantial quantities of conventional pollutants, particularly oil 

and grease. Consequently, EPA proposed to establish BPT limitations and NSPS for only two 

pollutants, TSS and oil and grease (as HEM), for direct dischargers in the SDD Subcategory 

based on Option 10 technology. This technology includes the following: (1) in-process flow 

control and pollution prevention, and (2) oil/water separation by chemical emulsion breaking and 

oil/water separation by dissolved air flotation (see Section 9.8.1). EPA proposed this technology 

basis because some existing SDD facilities use this technology and it projected significant 

reductions in conventional pollutants and determined that these reductions were cost reasonable. 

Following proposal, EPA received comments and supporting data indicating that 

its estimates of current pollutant discharges from this subcategory were overestimated. In 

particular, commentors claimed that current discharges of oil and grease were minimal and that 

national regulation was not warranted for this subcategory. 

For the final rule, EPA incorporated the additional information provided by 

commentors into its analysis. EPA continues to conclude that there are six direct discharging 

SDD facilities. However, EPA now concludes that direct discharges from these facilities 

9-35

9.0 - Technology Options 

generally contain minimal levels of all pollutants. In particular, EPA’s database indicates that 

regulation of oil and grease in direct discharges from SDD facilities is unwarranted because 

current oil and grease discharges from these facilities are not detectable (< 5 mg/L) or nearly not 

detectable. EPA has similarly determined that it should not establish nationally applicable 

limitations and standards for TSS because TSS discharges are, on average, minimal. The data 

show that TSS discharges may increase episodically, particularly when the dry dock is 

performing abrasive blasting operations cleaning. However, EPA has concluded that these 

episodic discharges from six facilities do not warrant national regulation. 

Therefore, nationally applicable regulations for new and existing SDD direct 

dischargers are unnecessary at this time and these facilities will remain subject to permit 

limitations established on a case-by-case basis using BPJ. 

9.9.2 PSES and PSNS 

EPA proposed not to establish pretreatment standards for existing and new 

indirect dischargers in the SDD Subcategory based on the small number of facilities in this 

subcategory and on the small quantity of toxic pollutants removed by the technology options 

evaluated by EPA at proposal (i.e., less than 26 PE removed annually per facility (see 66 FR 

471)). For the same reasons set out in the 2001 proposal, EPA is not promulgating pretreatment 

standards for existing or new indirect dischargers in this subcategory. These facilities remain 

subject to the General Pretreatment Standards (40 CFR 403) and local limits. 

9.10	 Summary of Technology Options Considered and Selected for the Final 

MP&M Rule 

Table 9-1 summarizes all of the technology options considered for the MP&M 

subcategories for either the proposed or final rules. Table 9-2 summarizes EPA’s selected 

technology bases for the final rule. 

9-36

Table 9-1


Technology Options by Subcategory


9-37


Treatment or Source Reduction Technology 

Technology Options Considered for the General Metals, Metal Finishing 

Job Shops, Printed Wiring Board, Steel Forming and Finishing, and NonChromium Anodizing Subcategoriesa 

Technology Optio

Wastes, Shipbuildi

Line Mainte

1 2 2S 3 4 

413 to 433 

Upgrade 

Local Limits 

to 433 

Upgrade 5 6 7 

Chemical Precipitation � � � � � � �Gravity Clarification for Metal Hydroxide Removal � � � � �Microfiltration for Metal Hydroxide Removal � �Chemical Emulsion Breaking Followed by Gravity 

Separation for Oil Removal 

� � � � � � �

Ultrafiltration for Oil Removal � � � Chemical Emulsion Breaking Followed by Dissolved Air 

Flotation for Oil Removal 

Alkaline Chlorination for Cyanide Removal � � � � � � �Chemical Reduction of Hexavalent Chromium � � � � � � �Chelation Breaking/Precipitation to Remove Complexed 

Metals 

� � � � � � �

Contract Hauling of Organic Solvent-Bearing 

Wastewater Instead of Discharge 

� � � � � � � � � � 

Countercurrent Cascade Rinsing to Conserve Water � � � � Centrifugation of Painting Water Curtains to Extend Life � � � � Centrifugation and Pasteurization of Machining 

Coolants to Extend Life 

� � � � 

Sand Filter to Remove Additional Suspended Solids �Sludge Dewatering and Disposal � � � � � � � 

aSee Section 9.2.2 for a discussion of BCT options considered for the General Metals Subcategory.
bEPA evaluated Option 5 for the Oily Wastes Subcategory only, Option 6 for the Oily Wastes and Railroad Line Maintenance Subcategories only, and Options 9 and 10 

and Railroad Line Maintenance Subcategories only. See Sections 9.7.2, 9.8.2, and 9.9.1 for discussions of BCT options considered for these subcategories.

9.0 - Technology Options 

Table 9-2


Summary of Technology Bases for the Final Rule


Subcategory Regulatory Level Technology Basis 

General Metals BPT/BCT/BAT/NSPS No new or revised limitations or standards established 

PSES/PSNS No new or revised standards established 

Metal Finishing Job Shops BPT/BCT/BAT/NSPS No new or revised limitations or standards established 

PSES/PSNS No new or revised standards established 

Printed Wiring Board BPT/BCT/BAT/NSPS No new or revised limitations or standards established 

PSES/PSNS No new or revised standards established 

Non-Chromium Anodizing BPT/BCT/BAT/NSPS No new or revised limitations or standards established 

PSES/PSNS No new or revised standards established 

Steel Forming and 

Finishing 

BPT/BCT/BAT/NSPS No new or revised limitations or standards established 

PSES/PSNS No new or revised standards established 

Oily Wastes BPT/BCT/NSPS Option 6: In-process pollution prevention, recycling, 

and water conservation methods; and chemical emulsion 

breaking followed by oil/water separation 

BAT No new or revised limitations established 

PSES/PSNS No new or revised standards established 

Railroad Line Maintenance BPT/BCT/BAT/NSPS No new or revised limitations or standards established 

PSES/PSNS No new or revised standards established 

Shipbuilding Dry Dock BPT/BCT/BAT/NSPS No new or revised limitations or standards established 

PSES/PSNS No new or revised standards established 

9-38

9-39

Figure 9-1. -Pipe Treatment Train for Options 1 and 2 Considered for the Following Sub

General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Board, 

Forming and Finishing

End-of
9-40

Figure 9-2. -Process Water Use Reduction Technologies for Options 2 and 4 Considered f

Following Subcategories: General Metals, Metal Finishing Job Shops, Non-Chromium

Anodizing, Printed Wiring Board, and Steel Forming and Finishing

In
9-41

Figure 9-3. -Pipe Treatment Train for Options 3 and 4 Considered for the Following Sub

General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Board, 

Forming and Finishing

End-of
9.0 - Technology Options

9-42

Figure 9-4. nd-of-Pipe Treatment Train for Options 5 and 6 Considered for the

Following Subcategories: Oily Wastes and Railroad Line Maintenance

Figure 9-5. -Pipe Treatment Train for Option 7 and 8

Considered for the Following Subcategories: Oily Wastes,

Railroad Line Maintenance, Shipbuilding Dry Dock

E

End-of
9.0 - Technology Options

9-43

Figure 9-6. nd-of-Pipe Treatment Train for Options 9 and 10 Considered for

the Following Subcategories: Railroad Line Maintenance and Shipbuilding Dry Dock

E
10.0 - Limitations and Standards: Data Selection and Calculation 

10.0	 LIMITATIONS AND STANDARDS: DATA SELECTION AND 

CALCULATION 

This section describes the data sources, data selection, data conventions, and 

statistical methodology used by EPA in calculating the long-term averages, variability factors, 

and daily maximum limitations. The effluent limitations and standards1 are based on long-term 

average effluent values and variability factors that account for variation in treatment performance 

within a particular treatment technology over time. As explained in the preamble to the rule, 

EPA is promulgating daily maximum limitations only for the Oily Wastes Subcategory. This 

section describes the data selection and calculations for the daily maximum limitations for total 

suspended solids (TSS) and oil and grease measured as n-hexane extractable material (O&G). 

Section 10.1 gives a brief overview of data sources (a more detailed discussion is 

provided in Chapter 3) and describes EPA’s evaluation and selection of episode data sets that are 

the basis of the limitations. Section 10.2 provides a more detailed discussion of the selection of 

the episodes and data for each pollutant. Section 10.3 presents the procedures for data 

aggregation. Section 10.4 provides an overview of the daily maximum limitations. Section 10.5 

describes the procedures for and summary of the estimation of long-term averages, variability 

factors, and limitations. Section 10.6 presents an evaluation of the limitations. 

10.1 Overview of Data Selection 

To develop the long-term averages, variability factors, and limitations, EPA used 

concentration data from facilities with the Option 6 technology in the Oily Wastes Subcategory. 

These data were collected from two sources, EPA’s sampling episodes and self-monitoring data. 

All sampling episodes were conducted using the EPA sampling and chemical 

analysis protocols as described in Section 3.3. Sampling episode reports maintained in the 

rulemaking record present the data collected during each sampling episode. 

In comments on the proposal and from other sources, EPA received compliance 

monitoring data from industry. These data are sometimes referred to as ‘Discharge Monitoring 

Report’ (DMR) or self-monitoring data. EPA denoted these data with a ‘D’ appended to the 4-

digit episode identifier, the same 4-digit number used for EPA sampling data at that facility. In 

the statistical analyses, the self-monitoring data are treated separately from the EPA sampling 

data. This practice is consistent with other guidelines and is used because the data tend to be 

associated with different time periods and/or analytical methods than EPA sampling data. 

Following the 2001 proposal and 2002 NODA, EPA received many comments on 

its selection of facilities and datasets used as the basis of its limitations. In response to these 

comments, EPA revisited its selection of facilities operating the Option 6 technology in the Oily 

Wastes Subcategory. As discussed in Section 10.2, for the episode datasets that were used to 

1

In the remainder of this chapter, references to ‘limitations’ includes ‘standards.’ 

10-1 
10.0 - Limitations and Standards: Data Selection and Calculation 

develop the final MP&M limitations, EPA performed a detailed review of the data and all 

supporting documentation accompanying the data. This was done to ensure that the selected data 

represent a facility’s normal operating conditions and that the data accurately reflect the 

performance expected by the production method and treatment systems. Thus, EPA evaluated 

whether the data were collected while a facility was experiencing exceptional incidents (upsets). 

EPA also examined the range of unit operations covered by the facilities. As part 

of its detailed review, EPA verified that it had selected facilities that generated wastewater that 

encompassed the unit operations that generated the most concentrated types of wastewater in the 

Oily Wastes Subcategory. (Section IV.A.3.6 of the preamble to the final rule identifies the unit 

operations in the Oily Wastes Subcategory.) 

In evaluating the data for the rule, EPA relied on two major sources of data: 

sampling episode reports and data review narratives. 

The sampling episode report (SER) describes the collection, analysis, and results 

of EPA’s comprehensive sampling at a facility in support of effluent guidelines rulemakings. 

Each SER presents a general overview of facility operations, includes process diagrams of 

treatment operations, summarizes the sample fractions collected for each sample point, describes 

any deviations from the sampling and analysis plan, provides flow and production information, 

and lists the analytical data results. SERs are located in Sections 5.2 and 15.3 of the record. 

The data review narratives (DRNs) present an assessment of the quality of the 

analytical (chemical) data, based upon a five-stage review process. The DRNs are included as an 

attachment to each SER. Because the data are the basis of the limitations, EPA determined that 

an additional evaluation of the laboratory submissions was appropriate. As a result of that 

evaluation, EPA confirmed that its previous determinations were appropriate for the TSS data 

and most oil and grease data. As explained in Section 10.2, EPA excluded some oil and grease 

data as a result of the evaluation. (See DCN 36500 in Section 28.5 of the record for a summary 

of the evaluation.) 

10.2 Episode and Data Selection 

This section describes the episodes selected for EPA’s evaluations of the 

technology option for the Oily Wastes Subcategory. Table 10-1 summarizes the episode and 

sample point selections, and Table 10-2 identifies the unit operations for each facility. 

10-2

10.0 - Limitations and Standards

Table 10-1


Oily Wastes Subcategory Oil/Water Separation


10-3


Episode 

No. 

Treatment Type (specific information on treatment 

from LTA folders, batch vs. continuous)1,2 

Discharger 

Type 

(indirect/ 

direct) 

Type of Data (EPA 

sampling, industry 

sampling episode, 

comment data) 

Influent 

Sampling 

Point 

E

Sa

P

4471 Process: Eq, skim, CE, O/W, CPT, sed 

Batch vs. Cont: continuous 

Additives: H2SO4, ferric chloride, lime, polymer 

Targets: unspecified 

Flow: unspecified 

Indirect EPA sampling SP-1 SP

4851 Process: API, eq, CE, skim 

Batch vs. Cont: continuous 

Additives: CO2, aluminum chloride 

Targets: Oil and grease, metals, organics Flow: 9,900-12,000 gph during sampling 

Indirect EPA sampling SP-11 SP

4872 Process: CE, O/W, oil cooking 

Batch vs. Cont: batch 

Additives: H2SO4, NaOH, alum, polymer 

Targets: Oil and grease Flow: design max 433,000 gal/batch × 2 batches/day; 

during sampling 433,133 gal/batch × 1 batch/day 

Indirect EPA sampling SP-4 SP

4872D Same as above Indirect Industry-supplied 

DMR data 

N/A SP

4876 Process: CE, O/W, gravity flot, DAF, oil cooking 

Batch vs. Cont: batch 

Additives: polymer, alum, NaOH, H2SO4 Targets: Oil and grease, TSS 

Flow: 152,000 gpd 

Indirect EPA sampling SP-4 SP
10.0 - Limitations and Standards

Table 10-1 (Continued)


Episode 

No. 

Treatment Type (specific information on treatment 

from LTA folders, batch vs. continuous)1,2 

Discharger 

Type 

(indirect/ 

direct) 

Type of Data (EPA 

sampling, industry 

sampling episode, 

comment data) 

Influent 

Sampling 

Point 

E

Sa

P

4877 Process: Eq, CE, O/W, oil cooking 

Batch vs. Cont: batch 

Additives: polymer, alum, NaOH, H2SO4, floc 

Targets: unspecified 

Flow: 100,000-200,000 gpd 

Indirect EPA sampling SP-4 SP

1Process abbreviations: 

API = API separator CE = chemical emulsion breaking 

CPT = chemical precipitation 

DAF = dissolved air flotation 

Eq = flow equalization 

Gravity flot = gravity flotation 

O/W = oil/water separation 

Sed = sedimentation 

Skim = oil skimmer 

2Treatment units or additives represented by the sampling points are in bold. 

10-4

10.0 - Limitations and Standards: Data Selection and Calculation 

Table 10-2


Unit Operations at Each Episode


Unit 

Operation Description 4471 4851a 

4872/ 

4872Db 4876 4877 

01 Abrasive Blasting dry dry X 

05 Alkaline Cleaning for Oil Removal X X X X 

07 Alkaline Treatment Without Cyanide 

10 Aqueous Degreasing X dry X 

11 Assembly/Disassembly dry X dry X dry 

12 Barrel Finishing 

13 Burnishing 

17 Corrosion Preventative Coating X 

18 Electrical Discharge Machining 

26 Floor Cleaning X X X X 

27 Grinding X X X X 

28 Heat Treating X zero 

29 Impact Deformation dry X X 

30 Machining X X X X X 

32 Painting (Spray or Brush) X dry zero zero 

35 Polishing X 

36 Pressure Deformation 

39 Solvent Degreasing X 

42 Testing (Such as Hydrostatic, Dye 

Penetrant, Ultrasonic, Magnetic Flux) 

X X X X 

43 Thermal Cutting 

44 Washing of Final Products X X 

45 Welding dry dry dry 

46OR Wet Air Pollution Control of Organic 

Constituents 

zero X 

65 Steam Cleaning 

71 Adhesive Bonding 

72 Calibration 

Iron Phosphate Conversion Coating X 

a

4851 also performs chromium and nickel electroplating (nonoily operations) where the wastes are contract hauled 

and plasma arc machining (a nonoily operation) but never discharged to the water table. b

4872 also has manganese phosphate coating and leaking hydraulic oil from machines. 

10-5

10.0 - Limitations and Standards: Data Selection and Calculation 

As a first step, EPA reviewed all of its data from facilities with the Option 6 

treatment in the Oily Wastes Subcategory. Table 10-1 identifies all of the episodes with Oily 

Wastes Subcategory oil/water separation treatability data in EPA’s database. EPA has data from 

six different sampling episodes: five are EPA sampling episodes (4471, 4851, 4872, 4876, 4877) 

and one is industry-supplied DMR data (4872D). For the final rule, EPA based the oil and grease 

limitations on the data from Episodes 4872, 4872D, and 4877 and the TSS limitation on the data 

from Episode 4851. The following describes EPA’s evaluation of each of the six episodes and 

its decisions to include or exclude the data. As shown in Table 10-2, these episodes encompass a 

variety of unit operations included in the Oily Wastes Subcategory. 

Episode 4471 was conducted at a facility that manufactured magnum tractors for 

the farming industry. The facility’s primary water-using unit operations included alkaline 

cleaning, grinding, heat treating, painting, and testing of the finished product. Episode 4471 

operated chemical precipitation and sedimentation following the Option 6 technology. 

Consequently, the facility did not need to rely on the Option 6 technology alone to meet any 

discharge requirements, and most likely optimized oil and grease and TSS removals following 

during the chemical precipitation and solids separation step. Consequently, its Option 6 

technology performance had removal rates of only 31 percent for TSS and 42 percent for oil and 

grease during the sampling episode. In contrast, the other facilities had removal rates of over 90 

percent for TSS and oil and grease using the Option 6 technology. In addition, EPA measured oil 

and grease using a freon method, rather than a hexane extractable method used for the other 

episodes. As explained in the NODA, the sampling data in Phase 1 (this includes Episode 4471) 

had been analyzed by EPA Method 413.2, a method utilizing freon that was unlikely to produce 

comparable results to methods approved under 40 CFR 136 (such as EPA Method 413.1). Thus, 

EPA did not use these data in determining the final daily maximum oil and grease limitation, 

because the facility had not optimized its Option 6 technology (because it did not need to do so) 

and the oil and grease data were not measured by a method comparable to those approved at 40 

CFR 136. 

Episode 4851 was conducted at a facility that repaired and manufactured 

locomotives. The facility’s primary water-using unit operations included alkaline cleaning, 

machining, and testing of the finished product. Episode 4851 operated the Option 6 technology 

and was used as the basis of the final TSS daily maximum limitation because this facility had the 

highest concentrations of TSS in the influent (except for Episode 4876, which EPA excluded as 

explained below). Episode 4851's average influent TSS concentration was 833 mg/L compared 

to the next highest TSS influent average of 219 mg/L at Episode 4872. Although this facility, on 

average, had concentrated TSS influent, it also had the lowest daily value for TSS in the influent 

that EPA observed in its sampling of facilities in this subcategory. Because EPA was concerned 

that this value might not represent normal operations for a facility that normally has concentrated 

TSS in its influent, it excluded this one value from its calculations of the limitation. In addition, 

EPA excluded all of the oil and grease effluent data based upon a review of the laboratory 

reports. Over the five-day period for the sampling episode, EPA collected 36 oil and grease 

samples at the effluent sample point. One sample (36240) broke and thus was not analyzed. For 

31 other samples (36232-36239, 36241-36263), when EPA performed a final review of the 

10-6

10.0 - Limitations and Standards: Data Selection and Calculation 

laboratory reports, it realized that the ongoing precision recoveries (OPR) were below the 

acceptable range of 79-144 percent that is specified in Method 1664. For the four remaining 

samples (36264-36267), EPA considered these values to be ‘minimum values’ because the 

matrix spike and its matrix sample duplicate (MS/MSD) recoveries were outside of the criteria in 

the method. For these reasons, EPA excluded the oil and grease data from Episode 4851. 

Episodes 4872 and 4872D are from a facility that manufactured automotive parts, 

including axles, shafts, tubes, housings, and transmission gear sets. The facility’s unit operations 

included machining, polishing, impact deformation (punch pressing), heat treatment (carburizing 

and tempering), and washing of the components. The facility also performed manganese 

phosphate coating and painting operations. In general, based on information obtained from 

episode 4872, the facility generated approximately 70 percent of the daily process wastewater 

from 21 aqueous parts washers, and approximately 30 percent from 14 machining operations 

containing a 5-percent solution of machining coolant. Less than 1 percent of the wastewater flow 

was generated from minor water-producing operations, including the paint booth water curtain, 

the manganese phosphate coating operation, heat treatment, and leaking hydraulic oil from 

machines (tramp oil). Because this facility also commingles wastewater generated by CFR 433 

operations (i.e., manganese phosphate coating) with wastewater generated by oily waste 

operations, it would be subject to 433 rather than 4382

. However, EPA determined it was 

appropriate to retain this facility in its Part 438 limitations calculations because the commingled 

wastewater from this facility largely comprises wastewater generated from oily waste operations 

(>99 percent). Furthermore, EPA compared the influent concentrations of the regulated 

parameters at this facility with those at other oily waste facilities and found them to be 

comparable. 

During the time periods of these episodes, this facility operated the Option 6 

technology to treat its wastewater. As noted in Section 10.1, EPA has treated its self-monitoring 

data separately from the EPA sampling data. The data for the two episodes were collected about 

two years apart (1997 for the sampling episode and 1999 for the self-monitoring episode). EPA 

expects that some changes in process, production mix, volume of production, and wastewater 

treatment systems were likely to have occurred during the two-year period and has used the data 

as if they were from two different facilities. EPA also notes that the ranges of the daily oil and 

grease effluent concentrations were different for the two episodes, with Episode 4872 ranging 

from 44.8 to 57.1 mg/L and Episode 4872D ranging from 8.6 to 23.6 mg/L. 

For Episode 4872, the treatment system consisted of a large batch tank in which 

the facility added emulsion breaking chemicals and then allowed the oil to separate from the 

water. The facility then discharged the water layer (i.e., the lower layer). Upon review of the 

operating procedures for this facility, EPA determined that the approach used to determine when 

to stop the draw-down was based solely on tank level, as opposed to being based on any type of 

measurement. While EPA has concerns about this approach and has incorporated costs in this 

rule for an upgrade to remove the subjectivity, EPA determined that the Episode 4872D data 

2

See 438.2(b) 

10-7

10.0 - Limitations and Standards: Data Selection and Calculation 

demonstrated that the system can achieve low concentrations of oil and grease when the 

treatment system is operated properly. For this reason, EPA has included all but one oil and 

grease value in calculating the limitation. EPA excluded the concentration value of 25.8 mg/L 

from the third grab sample (38970) on Day 1 of Episode 4872, because the MS/MSD percent 

recoveries were below the method criteria and the value is considered to be a minimum value. 

Because its field duplicate value was reported with a higher value of 65.9 mg/L and met the 

criteria in the data review guidelines, the field duplicate value was used in calculating the oil and 

grease limitation instead (i.e., sample 38970 was excluded). EPA also considered excluding the 

data value for the fourth grab sample (38971) on Day 1, because the MS percent recovery was 

below the method criteria and the relative percent difference (RPD) between the MS and its MSD 

also exceeded the method criteria. Despite these qualifiers, EPA decided to retain this sample 

because it was consistent with the value for its field duplicate (105 mg/L) which had met the 

method criteria. 

Episode 4876 was conducted at a facility that manufactured engines for 

automobiles and light trucks. The primary wastewater generating operations at this facility 

included machining and grinding operations, which require a water-based cutting fluid. The 

facility also performed alkaline cleaning operations. Episode 4876 treated its wastewater using a 

DAF system following the Option 6 technology. When EPA reviewed these data in detail, it 

found that the facility appeared to be optimizing its Option 6 portion of the treatment technology 

for TSS removals, but not oil and grease. Because the system was not optimized for oil and 

grease removals (because the facility additionally used the DAF system for this purpose), EPA 

excluded those data in calculating the oil and grease limitation. Although the facility had a 

removal rate of 99 percent for TSS, EPA excluded the TSS effluent data values because EPA had 

collected daily grab samples at this sample point, rather than daily composite samples that EPA 

expects that facilities would use in complying with the final TSS daily maximum limitation3

. As 

explained in Section 10.5, while it had excluded the data from its limitation calculations, EPA 

ultimately used these TSS data to evaluate the limitation. 

Episode 4877 was conducted at a facility that manufactured and assembled 

automatic transmissions and chassis components. Manufacturing processes included machining, 

grinding, impact deformation, abrasive blasting, and aqueous degreasing of the metal 

components. The facility also performed painting operations; however, no wastewater was 

generated from painting. In general, the facility generated approximately 75 percent of its 

process wastewater from 60 aqueous parts washers and 20 percent from 18 machine coolant 

recirculation filtration systems (hydromation pits), containing a 4- to 12-percent solution of 

coolant used for machining and grinding operations. Miscellaneous wastewater sources such as 

floor washing, leaking hydraulic oil, and transmission oil from hydrostatic testing were included 

in the remaining 5 percent of the flow. This facility treated its wastewater using the Option 6 

technology. In calculating the limitation, EPA excluded the oil and grease data from the second 

day because operation on that day was not representative of the normal operating conditions for 

3

 This system was a batch system that discharged over the course of 24 hours. EPA expects that facilities with this 

type of system would conduct continuous compliance monitoring. 

10-8 
10.0 - Limitations and Standards: Data Selection and Calculation 

Option 6 technology. As documented in the sampling episode report, on that day only, the 

operator failed to add the proper treatment chemicals. EPA also reviewed the laboratory reports 

and identified qualifiers on two of the effluent samples used to calculate the oil and grease 

limitation, but has included both results in calculating the oil and grease limitation. These 

samples were the third and fourth grab samples (39564 and 39565) collected on Day 1 of the 

sampling episode. For both samples, the RPD between the MS and its MSD exceeded the 

method criteria. In addition, the MSD recovery was below the method criteria for the fourth grab 

sample. In conjunction with those samples, EPA had collected field duplicates. The oil and 

grease limitation was calculated using daily values calculated from the average of each duplicate 

pair. When EPA calculated the daily value with the averages of each duplicate pair (see Section 

10.3), it found virtually no difference if the qualified data were included or excluded. Because 

their inclusion results in a minutely higher daily value for Day 1, the values for samples 39564 

and 39565 were included in calculating the limitations. 

10.3 Data Aggregation 

In developing the limitations, EPA modeled daily data values rather than 

individual sample measurements. EPA’s approach of aggregating multiple analytical results to 

obtain a single daily value is consistent with standard, conventional practice in environmental 

analytical work. This approach also gives one day's sampling information appropriate weight in 

determining effluent limitations and is consistent with requirements of NPDES regulations at 40 

CFR 122 which define the daily discharge. 

In some cases, EPA mathematically aggregated two or more samples to obtain a 

single value that could be used in other calculations. This occurred with field duplicates and grab 

samples collected over time to represent a single waste stream. Table 10-3 lists these values. 

Table 10-4 lists the influent and effluent data after these aggregations were completed and a 

single daily value was obtained for each day for each pollutant. 

In all aggregation procedures, EPA considered the censoring type associated with 

the data. EPA considered measured values to be detected. In statistical terms, the censoring type 

for such data was ‘noncensored’ (NC). The Agency censored measurements reported as being 

less than some sample-specific detection limit (e.g., <10 mg/L) and considered them to be 

nondetected (ND). In the tables and data listings in this document and the rulemaking record, 

EPA uses the abbreviations NC and ND to indicate the censoring types. The data used as a basis 

for the final limitations are all NC and thus all aggregated results also are considered to be NC. 

This subsection describes each of the different aggregation procedures. They are 

presented in the order that the aggregation was performed (i.e., field duplicates were aggregated 

first and grab samples second). Table 10-3 lists the effluent data before aggregation and Table 

10-4 lists the daily influent and effluent values after any aggregation. 

10-9

10.0 - Limitations and Standards: Data Selection and Calculation 

Table 10-3 	

Effluent Data Before Aggregationa	

Pollutant Episode 

Sample 

Day 

Original Sample 

Corresponding Field 

Duplicate (if any) 

Concentration (mg/L) Concentration (mg/L) 

Oil and 

Grease 

4872 1 23.1 

14.4 

108.0 

50.8 

23.3 

65.9 

105.0 

2 89.6 

54.5 

21.1 

14.1 

3 33.2 

63.1 

68.2 

57.9 

4877 1 25.0 

21.0 

33.0 

20.0 

26.0 

15.0 

20.0 

32.0 

3 12.0 

16.0 

10.0 

21.0 

4 21.0 

11.0 

24.0 

29.0 

5 13.0 

31.0 

8.0 

8.0 

TSS 4851 1 54.0 26.0 

2 40.0 30.0 

3 36.0 62.0 a

This table includes only values that were later aggregated with other values. See Table 10-4 for all daily values. 

10-10

10.0 - Limitations and Standards: Data Selection and Calculation 

Table 10-4 

Data After Aggregation (i.e., Daily Values) 

Pollutant Episode 

Sample 

Day 

Influent 

Daily Value (mg/L) 

Effluent 

Daily Value (mg/L) 

Oil and Grease 4872 1 

2 

3 

696 

2182 

502 

57.050 

44.825 

55.600 

4872D 1 

2 

3 

4 

12.100 

23.600 

15.200 

8.640 

4877 1 

3 

4 

5 

557 

997 

544 

469 

24.000 

14.750 

21.250 

15.000 

TSS 4851 1 

2 

3 

4 

1720 

508 

373 

615 

40.000 

35.000 

49.000 

48.000 

10.3.1 Aggregation of Field Duplicates 

During its sampling episodes, EPA collected field duplicates for quality control 

purposes. Generally, 10 percent of the number of samples collected were duplicated. Field 

duplicates are two samples collected for the same sampling point at the same time, assigned 

different sample numbers, and flagged as duplicates for a single sample point at a facility. 

Because the analytical data from each duplicate pair characterize the same conditions at that time 

at a single sampling point, EPA averaged the data to obtain one value for each duplicate pair. 

This aggregation step for the duplicate pairs was the first step in the aggregation procedures. 

10.3.2 Aggregation of Grab Samples 

During its sampling episodes, EPA collected two types of samples: grab and 

composite. For oil and grease, EPA collected four grab samples over the course of each day of 

sampling during each sampling episode. To obtain one value characterizing the oil and grease 

levels at the sample point on a single day, EPA arithmetically averaged the measurements to 

obtain a single value for the day. In developing the TSS limitation, EPA used the concentration 

values of daily composite samples from episode 4851, and thus, this aggregation step was not 

necessary. 

10-11

10.0 - Limitations and Standards: Data Selection and Calculation 

10.4 Overview of Limitations 

The preceding subsections discuss the data selected as the basis for the limitations 

and the data aggregation procedures EPA used to obtain daily values in its calculations. This 

subsection provides a general overview of limitations. 

The oil and grease and TSS limitations are provided as maximum daily discharge 

limitations. The definition provided in 40 CFR 122.2 states that the “maximum daily discharge 

limitation” is the “highest allowable daily discharge.” Daily discharge is defined as the 

“discharge of a pollutant measured during a calendar day or any 24-hour period that reasonably 

represents the calendar day for purposes of sampling.” 

EPA did not establish monthly average limitations for oil and grease and TSS 

because a monthly average limitation would be based on the assumption that a facility would be 

required to monitor more frequently than once a month. For the rule, EPA has determined that 

one monthly monitoring event is sufficient; however, if permitting authorities choose to require 

more frequent monitoring for oil and grease and TSS, they may set monthly average limitations 

and standards based on their best professional judgement. (See, e.g., 40 CFR 430.24(a)(1), 

footnote b.) 

The following three subsections describe EPA’s objective for daily maximum 

limitations, the selection of the percentile for those limitations, and compliance with final 

limitations. EPA has included this discussion in Section 10.0 because these fundamental 

concepts are often the subject of comments on EPA’s effluent guidelines regulations and in 

EPA’s contacts and correspondence with industry. 

10.4.1 Objective 

In establishing daily maximum limitations, EPA’s objective is to restrict the 

discharges on a daily basis to a level that is achievable for a facility that targets its treatment at 

the long-term average. EPA acknowledges that variability around the long-term average results 

from normal operations. This variability means that occasionally facilities may discharge at a 

level that is lower than or greater than the long-term average. To allow for possibly higher daily 

discharges, EPA has established the daily maximum limitation. A facility that discharges 

consistently at a level near the daily maximum limitation would not be operating its treatment 

system to achieve the long-term average, which is part of EPA’s objective in establishing the 

daily maximum limitations. That is, targeting treatment to achieve the limitations may result in 

frequent values exceeding the limitations due to routine variability in treated effluent. 

In estimating the limitations, EPA first determines an average performance level 

(the “option long-term average” discussed in Section 10.5) that a facility with well-designed and 

operated model technologies (that reflect the appropriate level of control) is capable of achieving. 

This long-term average is calculated from the data from the facilities using the model 

technologies for the option. EPA expects that all facilities subject to the final limitations will 

10-12

10.0 - Limitations and Standards: Data Selection and Calculation 

design and operate their treatment systems to achieve the long-term average performance level on 

a consistent basis because facilities with well-designed and operated model technologies have 

demonstrated that this can be done. 

Next, EPA determines an allowance for the variation in pollutant concentrations 

when wastewater is processed through extensive and well-designed treatment systems. This 

allowance incorporates all components of variability, including shipping, sampling, storage, and 

analytical variability. This allowance is incorporated into the limitations through the use of the 

variability factors that EPA calculated from the data from the facilities using the model 

technologies. If a facility operates its treatment system to achieve the relevant option long-term 

average, EPA expects the facility will be able to comply with the limitations. Variability factors 

assure that normal fluctuations in a facility’s treatment are accounted for in the limitations. By 

accounting for these reasonable excursions above the long-term average, EPA’s use of variability 

factors results in limitations that are generally well above the actual long-term averages. 

EPA calculates the percentile used as a basis for the daily maximum limitation 

using the product of the long-term average and the daily variability factor. The following 

subsection describes EPA’s rationale for selecting the 99th percentile as the basis for the daily 

maximum limitations. 

10.4.2 Selection of Percentiles 

EPA calculates limitations based upon percentiles chosen, on one hand, to be high 

enough to accommodate reasonably anticipated variability within control of the facility and, on 

the other hand, to be low enough to reflect a level of performance consistent with the Clean 

Water Act requirement that these effluent limitations be based on the “best” technologies. The 

daily maximum limitation is an estimate of the 99th percentile of the distribution of the daily 

measurements. 

The 99th percentile does not relate to, or specify, the percentage of time a 

discharger operating the “best available” or “best available demonstrated” level of technology 

will meet (or not meet) the limitations. Rather, EPA used this percentile in developing the daily 

maximum limitation. If a facility is designed and operated to achieve the long-term averages on 

a consistent basis and the facility maintains adequate control of its processes and treatment 

systems, the allowance for variability provided in the daily maximum limitations is sufficient for 

the facility to meet the requirements of the rule. EPA used 99 percent to draw a line at a definite 

point in the statistical distributions (100 percent is not feasible because it represents an infinitely 

large value), while setting the percentile at a level that would ensure that operators work hard to 

establish and maintain the appropriate level of control. By targeting its treatment at the longterm average, a well-operated facility should be able to comply with the limitations at all times 

because EPA has incorporated an appropriate allowance for variability into the limitations. 

In conjunction with the statistical methods, EPA performs an engineering review 

to verify that the limitations are reasonable based upon the design and expected operation of the 

10-13

10.0 - Limitations and Standards: Data Selection and Calculation 

control technologies and the facility process conditions. As part of that review, EPA examines 

the range of performance by the facility datasets used to calculate the limitations. Some facility 

datasets demonstrate the best available technology. Other facility datasets may demonstrate the 

same technology, but not the best demonstrated design and operating conditions for that 

technology. For these facilities, EPA will evaluate the degree to which the facility can upgrade 

its design, operating, and maintenance conditions to meet the limitations. If such upgrades are 

not possible, then EPA will modify the limitations to reflect the lowest levels that the 

technologies can reasonably be expected to achieve. 

10.4.3 Compliance with Limitations 

EPA promulgates limitations with which facilities can comply at all times by 

properly operating and maintaining their processes and treatment technologies. EPA uses a 

percentile of a statistical distribution in developing the daily maximum limitation because 

statistical methods provide a logical and consistent framework for analyzing a set of effluent data 

and determining values from the data that form a reasonable basis for effluent limitations. EPA 

establishes the limitations on the basis of percentiles estimated using data from facilities with 

well-operated and controlled processes and treatment systems. However, because EPA uses a 

percentile basis, the issue of exceedances (i.e., values that exceed the limitations) or excursions is 

often raised in public comments on limitations. For example, comments often suggest that EPA 

include a provision that allows a facility to be considered in compliance with permit limitations if 

its discharge exceeds the daily maximum limitations one day out of 100. This issue was, in fact, 

raised in other rules, including EPA’s final Organic Chemicals, Plastics, and Synthetic Fibers 

(OCPSF) rulemaking. EPA’s general approach there for developing limitations based on 

percentiles is the same in this rule, and was upheld in Chemical Manufacturers Association v. 

U.S. Environmental Protection Agency, 870 F.2d 177, 230 (5th Cir. 1989). The Court 

determined that: 

EPA reasonably concluded that the data points exceeding the 99th


and 95th percentiles represent either quality-control problems or


upsets because there can be no other explanation for these isolated


and extremely high discharges. If these data points result from


quality-control problems, the exceedances they represent are within


the control of the plant. If, however, the data points represent


exceedances beyond the control of the industry, the upset defense


is available.


Id. at 230.


As that Court recognized, EPA’s allowance for reasonably anticipated variability 

in its effluent limitations, coupled with the availability of the upset defense, reasonably 

accommodates acceptable excursions. Any further excursion allowances would go beyond the 

reasonable accommodation of variability and would jeopardize the effective control of pollutant 

discharges on a consistent basis and/or bog down administrative and enforcement proceedings in 

detailed fact-finding exercises, contrary to Congressional intent. See, as an example, Rep. No. 

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10.0 - Limitations and Standards: Data Selection and Calculation 

92-414, 92d Congress, 2d Sess. 64, reprinted in A Legislative History of the Water Pollution 

Control Act Amendments of 1972 at 1482; Legislative History of the Clean Water Act of 1977 at 

464-65. 

EPA expects that facilities will comply with promulgated limitations at all times. 

If an exceedance is caused by an upset condition, the facility would have an affirmative defense 

to an enforcement action if the requirements of 40 CFR 122.41(n) are met. If the exceedance is 

caused by a design or operational deficiency, then EPA has determined that the facility’s 

performance does not represent the appropriate level of control. For promulgated limitations and 

standards, EPA has determined that such exceedances can be controlled by diligent process and 

wastewater treatment system operational practices such as frequent inspection and repair of 

equipment, use of back-up systems, and operator training and performance evaluations. 

EPA recognizes that, as a result of the rule, some dischargers may need to 

improve treatment systems, process controls, and/or treatment system operations in order to 

consistently meet the effluent limitations. EPA believes that this consequence is consistent with 

the Clean Water Act statutory framework, which requires that discharge limitations reflect the 

best technology. 

10.5 Calculation of the Limitations 

This section discusses the calculation of the daily maximum limitations for TSS 

and oil and grease. 

First, EPA calculated the episode long-term average and daily variability factor by 

using the modified delta-lognormal distribution (see Appendix E). Table 10-5 lists these 

episode-specific values. 

Table 10-5 

Episode Long-Term Averages and Daily Variability Factors 

Pollutant Episode 

Episode Long-Term Average 

(mg/L) 

Episode Daily Variability 

Factor 

Oil and grease 4872 52.6533 1.3489 

4872D 15.2101 2.4403 

4877 18.8921 1.7203 

TSS 4851 43.1442 1.4312 

Second, EPA calculated the option long-term average for a pollutant as the 

median of the episode-specific long-term averages for that pollutant. The median is the midpoint 

of the values ordered (i.e., ranked) from smallest to largest. For oil and grease, when the three 

10-15 
10.0 - Limitations and Standards: Data Selection and Calculation 

episode long-term averages are ordered, this midpoint value is 18.89 mg/L from Episode 4877. 

For TSS, this midpoint value is the same as the episode long-term average from Episode 4851. 

Third, EPA selected the option daily variability factor. For oil and grease, EPA 

used the self-monitoring data, Episode 4872D, as the basis of the option daily variability factor. 

In the proposal and NODA, when EPA used multiple episodes as the basis of a limitation, it used 

the mean of the episode daily variability factors. That practice was consistent with EPA’s 

development of limitations for other industries. However, for this pollutant in this subcategory, 

EPA has determined that it is appropriate to deviate from its normal practice, because each of the 

self-monitoring measurements were obtained several months apart (i.e., 2/23/99, 4/29/99, 

8/11/99, and 10/28/99). As explained in the NODA, EPA intended to investigate whether 

autocorrelation was likely to be present in the data. When data are positively autocorrelated, it 

means that measurements taken at specific time intervals (such as 1 day or 2 days apart) are 

related. To determine autocorrelation in the data, many measurements for each pollutant would 

be required with values for every single day over an extended period of time. Despite its requests 

to industry, the data were not made available to EPA for Option 6 oily wastes effluent. However, 

by selecting the self-monitoring data, each measured several months apart, as the basis of the 

option daily variability factor, EPA has avoided the possibility of autocorrelation existing in the 

data used as a basis of the option daily variability factor for oil and grease. For TSS, the option 

daily variability factor is the same as the episode daily variability factor from Episode 4851, 

because EPA used the data from that facility as the basis for the limitation as explained in 

Section 10.2. While autocorrelation might exist in the Episode 4851 data, EPA selected a facility 

with high concentrations of TSS in the influent as the basis of the option daily variability factor. 

EPA notes that no facilities with the Option 6 technology with similar high concentrations of 

TSS influents provided any daily measurements of TSS effluent concentrations. From the 

information that EPA had available to it, EPA determined that the allowance for variability 

provided by the Episode 4851 data was sufficient and the limitation was demonstrated to be 

achievable, as described later in this subsection. 

Fourth, EPA calculated each daily maximum limitation for a pollutant using the 

product of the option long-term average and the option daily variability factor. EPA rounded the 

limitation to two significant digits. The rounding procedure rounds up values of five and above, 

and rounds down values of four and below. Table 10-6 provides the option long-term average, 

option daily variability factor, and the daily maximum limitation. 

10.6 Evaluation of the Limitations 

To evaluate the limitations, EPA compared the daily maximum limitations to all 

of the effluent data that it had received from facilities in the Oily Wastes Subcategory. In 

addition, EPA compared the values of the final daily maximum limitation to the values presented 

in the 2001 proposal and the 2002 NODA. The following subsections describe these evaluations. 

10-16

10.0 - Limitations and Standards: Data Selection and Calculation 

Table 10-6 	

Option Long-Term Averages, Daily Variability Factors, and Limitations	

Pollutant 

Option Long-Term Average 

(mg/L) 

Option Daily Variability 

Factor 

Daily Maximum 

Limitation (mg/L) 

Oil and grease 19 2.4 46 

TSS 43 1.4 62 

10.6.1 Comparison to Data 

This section compares the daily maximum limitations to all of the data that EPA 

had available to it from the Oily Wastes Subcategory. In the following subsections, EPA first 

evaluated the TSS limitation and then the oil and grease limitation. In addition, EPA compared 

the data from each facility to both limitations, because it had received many comments stating 

that facilities would have difficulty complying with multiple limitations simultaneously. From 

its conclusions about the data comparisons, EPA has determined that the data do not support 

such assertions. As a result of the data comparisons and reviews described below, EPA has 

concluded that facilities that properly design and operate to achieve the option long-term average 

will be able to comply with the limitations. 

Total Suspended Solids Limitation 

For TSS, none of the daily values from Episode 4851 (i.e, the basis of the 

limitation) were greater than the daily maximum limitation of 62 mg/L. EPA performed this 

comparison to determine whether it used appropriate distributional assumptions for the data used 

to develop the limitations (i.e., whether the curves EPA used provide a reasonable “fit” to the 

actual effluent data4

 or if there was an engineering or process reason for an unusual discharge). 

As a result of this comparison, EPA determined that the distributional assumptions appear to be 

appropriate for these data. As a further evaluation of these limitations, EPA compared the 

individual measurements from field duplicate pairs and also found that none of the individual 

values were greater than the limitation. 

EPA performed additional comparisons of the limitation to other EPA sampling 

data obtained from the Option 6 technology in the Oily Wastes Subcategory, although they were 

not used as a basis of the limitation. EPA compared the limitation to the TSS data values from 

Episode 4876 (see Section 10.2 for EPA’s reasons for excluding these data from its limitation 

4

EPA believes that the fact that the Agency performs such an analysis before promulgating limitations might give the 

impression that EPA expects occasional exceedances of the limitations. This conclusion is incorrect. EPA 

promulgates limitations that facilities are capable of complying with at all times by properly operating and 

maintaining their treatment technologies. 

10-17 
10.0 - Limitations and Standards: Data Selection and Calculation 

calculations). Although this episode had more concentrated TSS influent than Episode 4851 

(which was the basis for the limitation), all of its TSS effluent data values were considerably less 

than the daily maximum limitation. In addition, none of the individual measurements exceeded 

the option long-term average of 43 mg/L. For the episodes that EPA excluded from the 

limitations calculations because they had less concentrated influents (Episodes 4872, 4872D, and 

4877), all of the daily values and individual values in each field duplicate pair were below the 

option long-term average, except for the data from the second sampling day during Episode 4877 

when the facility did not add the proper treatment chemicals. During Episode 4471, the facility 

achieved levels lower than the limitation on three sampling days even though the facility had not 

optimized its treatment system. EPA notes that the single effluent value greater than the 

limitation was also greater than its corresponding influent value, and thus, the system did not 

demonstrate any removals of TSS on that day. (See DCNs 36000S and 36034 in Section 19.1 of 

the record and DCN 00573 in Section 5.2.32.1.) 

EPA also compared the TSS limitation to the sampling episode and selfmonitoring data obtained from three facilities (4819, 4820, and 4824) that treated oily wastes 

using ultrafiltration systems. The average influent concentrations at these facilities ranged from 

128 mg/L to 10,100 mg/L. During the sampling episodes and their own self-monitoring, none of 

the facilities had average concentration values that were greater than 12 mg/L, which is 

substantially less than the option long-term average of 43 mg/L used in calculating the limitation. 

Furthermore, during EPA’s sampling episodes, none of the effluent data values were greater than 

17 mg/L. 

EPA compared the TSS limitation to the data from Episode 7052P that operated 

DAF technology in addition to the Option 6 technology. The influent values ranged from 212 to 

4440 mg/L. This facility demonstrated treatment performance levels below the option long-term 

average for each of the four days that the facility sampled. 

As a further evaluation of its TSS daily maximum limitation, EPA examined TSS 

monitoring data provided by the questionnaire respondents that operated facilities in the Oily 

Wastes Subcategory, including two facilities that operated the Option 6 technology. Each facility 

provided the average of its TSS concentrations for one year, but not the individual measurements 

or the influent concentrations (because the questionnaire did not request this information). For 

both Option 6 facilities, the average TSS concentrations were below the daily maximum 

limitation as well as the long-term average. Other than these two facilities, the questionnaire 

respondents in the Oily Wastes Subcategory either reported that they used a different technology 

than Option 6 or did not provide TSS average concentrations. Except for two facilities, the 

reported TSS long-term averages were all less than the option long-term average. One of the two 

exceptions used a treatment technology that was less sophisticated than Option 6, and thus, it is 

to be expected that it would have a higher TSS average concentration than demonstrated by 

Option 6. The other exception operated a carbon adsorption and oil/water separation treatment 

system. Operated properly, this treatment technology is equivalent or better than the Option 6 

technology. EPA did not receive sufficient information in the survey from this facility to conduct 

a detailed engineering analysis of their unit operations and treatment system. Using the limited 

information that it had, EPA compared this facility’s unit operations and wastewater generating 

10-18

10.0 - Limitations and Standards: Data Selection and Calculation 

operations to similar facilities in this subcategory, and found no factors that would prevent this 

facility from achieving the demonstrated TSS removal of Option 6. Furthermore, this facility did 

not provide comments to EPA stating that it would be unable to meet the TSS limitations in the 

proposed rule or the NODA. EPA considers that it may be possible that the carbon adsorption 

system was overloaded on one or more occasions resulting in large TSS discharges that affected 

the overall average TSS value reported by the facility. To ensure that the facility would be 

capable of complying with the limitation, EPA assigned a one-time unit upgrade cost to this 

facility which includes contractor fees, operator training, and additional treatment controls. With 

this cost for additional system optimization, the site should be able to comply with the daily 

maximum limitation. 

Oil and Grease Limitation 

For oil and grease, EPA compared the daily maximum limitations to the data from 

Episodes 4872, 4872D, and 4877 which were used as the basis of the limitation. None of the 

daily values or even the individual values for grab samples from Episodes 4872D and 4877 were 

greater than the daily maximum limitation of 46 mg/L. For Episode 4872, EPA found some daily 

values (and values for individual grab samples) that were greater than the daily maximum 

limitation. While EPA recognizes that the data from this episode forms the technology basis of 

the oil and grease limitation, based upon its review of the data, EPA concluded that 

improvements to its system would optimize its treatment performance. Based upon this review, 

EPA also discussed the possibility of excluding these data from developing the daily maximum 

limitation because the data probably reflect less than optimal performance.5 EPA decided to 

maintain a conservative approach by retaining these data in developing the limitation.6 As a 

result of this comparison, EPA determined that the distributional assumptions appear to be 

appropriate for effluent data from the Option 6 technology. 

EPA performed additional comparisons of the limitation to other EPA sampling 

data obtained from the Option 6 technology in the Oily Wastes Subcategory, although the data 

were not used as a basis of the limitation. During Episode 4876, the system still achieved levels 

lower than the daily maximum limitation on two of the sampling days although it was not 

optimized for oil and grease removals. Although EPA used most of the data from Episode 4877 

in calculating the limitation, it had excluded the data for the second sampling day as explained in 

Section 10.2. This daily value was greater than the limitation, which is what EPA expects from a 

system operating without the proper treatment chemicals. EPA did not compare the Episode 

4177 and 4851 data values to the limitation because any conclusions would have been hard to 

5

A review of the treatment technology as this facility demonstrates that this facility lacks some parts of the Option 6 

technology basis (i.e., skimmer). 

6

Because EPA did not include this facility in its sample for the questionnaire, it did not include costs for it in the rule. 

Also, as explained in Sections 11.0 and 12.0, EPA only estimated compliance costs and loadings reductions for 

facilities in its cost and loads model database. Had this been a costed facility, EPA would have included cost 

estimates for additional energy, labor and equipment for this facility to improve the operation of its current systems 

in order to comply with the daily maximum limitation. 

10-19 
10.0 - Limitations and Standards: Data Selection and Calculation 

interpret. As explained in Section 10.2, the data for Episode 4177 and 4851 were excluded due 

to concerns about the analytical method and the quality of the data. (See DCNs 36000S and 

36034 in Section 19.1 of the record and DCN 00573 in Section 5.2.32.1.) 

EPA also compared the oil and grease limitation to the sampling episode and selfmonitoring data obtained from the three ultrafiltration facilities. Two facilities (4819 and 4820) 

had average effluent values that were less than the option long-term average of 19 mg/L used in 

calculating the limitation, and their daily effluent values during EPA’s sampling episodes were 

all below the daily maximum limitation. These episodes had influent values ranging from 90 to 

144 for Episode 4820 and 689 to 857 for Episode 4819. For the third facility (4824), EPA’s 

sampling data had an average effluent value below the daily maximum limitation, although one 

daily value at 78 mg/L was greater than the limitation. During the sampling episode, the 

facility’s oil and grease influent values ranged from 660 to 3670 mg/L. The self-monitoring data 

(4824D) for that facility had an average value of 47 mg/L, which is greater than the limitation. 

However, this facility demonstrated poor performance of the ultrafiltration system during EPA’s 

sampling episode. It was only able to remove about half of the 5-day biochemical oxygen 

demand (BOD5) and chemical oxygen demand (COD) concentrations, resulting in effluent 

averages of 1390 mg/L and 5450 mg/L, respectively. Thus, because this facility did not achieve 

typical removal rates for pollutants generally well treated by ultrafiltration, EPA has determined 

that its concentrations of oil and grease are abnormally high and can be corrected by improved 

operations. 

EPA compared the oil and grease limitation to the data from the DAF facility 

(Episode 7052P). The effluent average concentration was below the option long-term average, 

with each daily concentration having a value less than the daily maximum limitation. The 

influent levels ranged from 212 to 1020 mg/L. 

As it had for TSS, EPA examined oil and grease monitoring data provided by the 

questionnaire respondents that operated facilities in the Oily Wastes Subcategory, including three 

facilities that operated the Option 6 technology. For two of the three Option 6 facilities, the 

average oil and grease concentrations were below the daily maximum limitation as well as the 

long-term average. For the third, the average oil and grease concentration was slightly above the 

long-term average (21 as compared to 19 mg/L), but well below the daily maximum limitation. 

In the questionnaire, the facility reported that it used Method 413.1 to measure oil and grease. 

Because EPA used only data measured by Method 1664 in developing the TSS limitation, the 

slight difference between the averages might be a result of the different solvents used in the two 

analytical methods or just normal variability that has been incorporated into the option daily 

variability factor. For the nonoption 6 facilities, the reported oil and grease long-term averages 

were all less than the option long-term average, except for the one facility that operated a less 

sophisticated treatment technology, resulting in a higher oil and grease average concentration 

value. In developing the rule, EPA also included costs for this facility to upgrade its treatment 

system to comply with the daily maximum limitation. 

10-20

10.0 - Limitations and Standards: Data Selection and Calculation 

Both Limitations 

To respond to comments that stated that facilities would have difficulties 

complying with multiple limitations simultaneously, EPA compared the data from each facility to 

both limitations. 

For facilities with the Option 6 technology for which EPA had daily data values 

for both TSS and oil and grease concentrations, only Episode 4872 had any daily values that were 

greater than the oil and grease daily limitation and none were greater than the TSS limitation. 

Thus, Episode 4872 was still able to treat its TSS and sometimes its oil and grease influent 

concentrations to low levels in the effluent, although, as explained above, it has not optimized its 

treatment system. 

For facilities with the ultrafiltration technology, two had average effluent values 

that were below both limitations. Although the third facility had poor removals of key 

parameters including oil and grease, it still had adequate TSS removals and the average effluent 

values were less than the TSS limitation. 

The facility with the DAF technology had daily concentration values below both 

limitations for each sampling day. 

For the seven facilities that provided averages of their monitoring data in the 

questionnaire, only two reported effluent averages above either limitation. One facility operates 

a technology that is less sophisticated than Option 6, and thus, it is not surprising that its effluent 

is more concentrated than Option 6 levels. The other facility reports that it operates the Option 6 

technology, but, while it was able to treat oil and grease to levels below detection, it had an 

average value greater than the TSS limitation. As explained above, EPA has incorporated costs 

into the rule for this facility to improve its operations. 

10.6.2 Comparison to Proposed and NODA Values 

EPA compared the TSS and oil and grease daily maximum limitations to the 

values in the 2001 proposed rule and the 2002 NODA. Table 10-7 shows the three sets of values. 

In the NODA, EPA requested comment on an approach that would select the higher value of the 

proposed and revised limitation. In general, the comments that EPA received did not address this 

approach, but rather focused on the data selection and achievability of the limitations. Thus, 

EPA has chosen to base the final limitations on its in-depth review of the episodes, as explained 

in Sections 10.1 and 10.2. As a result of these changes, the final oil and grease daily maximum 

limitation has a value that is greater than the proposed and NODA values; and the TSS daily 

maximum limitation has a value that is slightly less than the proposed and NODA values. EPA 

has determined that these are reasonable outcomes of its in-depth review of the data. 

10-21

10.0 - Limitations and Standards: Data Selection and Calculation 

Table 10-7 	

Daily Maximum Limitations: Proposal, NODA, and Final Rule	

Pollutant 2001 Proposal 2002 NODA Final Rule 

Oil and grease (mg/L) 27 45.9 46 

TSS (mg/L) 63 63.0 62 

10-22

11.0 - Costs of Technology Bases for Regulations 

11.0 COSTS OF TECHNOLOGY BASES FOR REGULATIONS 

This section presents EPA’s estimates of costs for the MP&M industry to comply 

with the technology options considered and described in Section 9.0. EPA estimated the 

compliance costs for each technology option in order to determine potential economic impacts on 

the industry. EPA also weighed these costs against the effluent reduction benefits resulting from 

each technology option. This section includes cost estimates for options and subcategorization 

schemes that EPA selected for promulgation and for those that EPA ultimately rejected. Section 

12.0 presents Agency estimates of corresponding annual pollutant loadings and removals. The 

Agency is reporting estimates of potential economic impacts associated with the total estimated 

annualized costs of the regulation separately, in the Economic, Environmental, and Benefit 

Analysis of the Final Metal Products & Machinery Rule (EEBA). 

Section 11.1 summarizes the costs associated with each stage of the regulation 

development process. The remainder of this section discusses the following information: 

� Section 11.2: Selection and development of cost model inputs; 

� Section 11.3: The methodology for estimating costs, including an 

overview of the cost model; 

� Section 11.4: The specific methodology and assumptions used to estimate 

costs for the Notice of Data Availability (NODA) and for analyses after 

the NODA; 

� Section 11.5: Design and cost elements for pollution prevention and endof-pipe technologies; 

� Section 11.6: Examples of how sites were allocated costs, from start to 

finish; and 

� Section 11.7: References used in this section. 

Tables are presented in the text and figures are located at the end of this section. 

11.1 Summary of Costs 

This subsection summarizes EPA’s final capital, operating and maintenance 

(O&M), and annualized cost estimates for each final regulatory option. Table 11-1 summarizes 

the capital and O&M costs and Table 11-2 summarizes the annualized costs. These tables also 

present costs for each 

11-1

11.0 - Costs of T

Table 11-1	

Incremental Capital and O&M Costs	

11-2


Subcategory 

Discharge 

Status 

Options 

Evaluated Since 

Proposal 

NODA Costs ($2001) Final Rule Costs ($200

Number 

of Sites 

Capital 

Costs 

O&M 

Costs 

Number 

of Sites 

Capital 

Costs 

General Metals Direct Option 2 1,521 215,372,532 406,618,406 228 16,302,446 10

Indirect Option 2, 1 MGY 

cutoff 

2,354 545,616,505 718,480,881 NA 

Upgrade Option NA 429 65,548,547 36

50% Local Limits NA 628 95,760,054 40

Metal Finishing Job Shops 

Direct Option 2 24 6,136,725 3,952,333 NA 

Indirect Option 2 1,270 252,665,620 167,585,291 NA 

Upgrade Option NA 314 51,694,660 11

Non-Chromium 

Anodizing 

Direct Option 2 (model 

site) 

35 21,726,209 35,625,488 19 2,473,423 6,

Indirect Not Proposed NA 

Printed Wiring Board 

Direct Option 2 4 1,117,553 222,423 NA 

Indirect Option 2 840 178,724,756 176,775,257 NA 

Upgrade Option NA 354 51,588,250 17

Steel Forming and Finishing 

Direct Option 2 41 12,089,100 28,744,590 Not Covered by MP&M 

Indirect Option 2 112 19,399,831 22,760,945 Not Covered by MP&M 

Oily Wastes Direct Option 6 2,749 14,578,563 34,841,549 2,382 6,505,602 13

Indirect Option 6, 2 MGY 

cutoff 

288 16,338,598 94,408,489 NA 
11.0 - Costs of T

Table 11-1 (Continued)	

Subcategory 

Discharge 

Status 

Options 

Evaluated Since 

Proposal 

NODA Costs ($2001) Final Rule Costs ($200

Number 

of Sites 

Capital 

Costs 

O&M 

Costs 

Number 

of Sites 

Capital 

Costs 

Railroad Line Maintenance 

Direct Option 10 31 5,941,283 3 NA 

Option 6 NA 9 See Footnot

Indirect Not Proposed NA 

Shipbuilding Dry Dock 

Direct Option 10 6 601,172 3,152,880 6 See Footnot

Indirect Not Proposed NA 

Source: EPA Costs & Loadings Model.


Note: Cost estimates presented in this table will not equal those presented in the EEBA. These estimates do not include costs for faciliti

close in the baseline.


NA - Not applicable.


Footnote A - Based on DMR data received both from the model facilities and in comments, EPA considered the final removals to be ne

Agency did not calculate exact final costs.


11-3

11.0 - Costs of T

Table 11-2	

Incremental Annualized Costs	

11-4


Subcategory 

Discharge 

Status 

Options Evaluated Since 

Proposal 

NODA Costs ($2001) Final Rule Costs ($2001

Number of 

Sites Annualized Costs 

Number of 

Sites Annualized C

General Metals Direct Option 2 1,521 431,321,635 228 12,452,31

Indirect Option 2, 1 MGY cutoff 2,354 781,063,094 NA 

Upgrade Option NA 429 43,678,33

50% Local Limits NA 628 51,715,96

Metal Finishing Job Shops 

Direct Option 2 24 4,656,215 NA 

Indirect Option 2 1,270 196,566,038 NA 

Upgrade Option NA 314 17,338,77

Non-Chromium 

Anodizing 

Direct Option 2 (model site) 35 38,117,484 19 6,867,838 

Indirect Not Proposed NA 

Printed Wiring Board 

Direct Option 2 4 350,606 NA 

Indirect Option 2 840 197,274,986 NA 

Upgrade Option NA 354 23,859,17

Steel Forming and Finishing 

Direct Option 2 41 30,131,210 Not Covered by MP&M 

Indirect Option 2 112 24,986,106 Not Covered by MP&M 

Oily Wastes Direct Option 6 2,749 36,513,710 2,382 13,856,47

Indirect Option 6, 2 MGY cutoff 288 96,282,526 NA 

Railroad Line Maintenance 

Direct Option 10 31 681,469 NA 

Option 6 NA 9 See Footnot

Indirect Not Proposed NA 
11.0 - Costs of T

Table 11-2 (Continued)	

Subcategory 

Discharge 

Status 

Options Evaluated Since 

Proposal 

NODA Costs ($2001) Final Rule Costs ($2001

Number of 

Sites Annualized Costs 

Number of 

Sites Annualized C

Shipbuilding Dry Dock 

Direct Option 10 6 3,221,834 6 See Footnot

Indirect Not Proposed NA 

Source: EPA Costs & Loadings Model.


Note: Cost estimates presented in this table will not equal those presented in the EEBA. These estimates do not include costs for faciliti

close in the baseline.


NA - Not applicable.


Footnote A - Based on DMR data received both from the model facilities and in comments, EPA considered the final removals to be ne

Agency did not calculate exact final costs.


11-5

11.0 - Costs of Technology Bases for Regulations 

option considered following proposal of the rule and compares EPA’s final cost estimates to 

those presented in the NODA. Cost estimates presented in this section differ from those 

presented in the EEBA because of additional EEBA annual costs (e.g., taxes and amortization). 

In addition, the EEBA cost estimates exclude facilities that EPA projected will close in the 

baseline (i.e., facilities already financially stressed without the additional compliance costs 

associated with this rule). The remainder of this section discusses the methodology EPA used to 

calculate its final cost estimates. For a discussion of the costing methodology EPA used at 

NODA, see Section 16 of the rulemaking record. 

11.2 Development of Cost Model Inputs 

This subsection describes the key inputs to the cost model: model sites, 

wastewater discharge parameters, pollutant concentrations, and technology in place. This section 

also discusses the data sources used to determine these parameters. Section 11.3 describes how 

the cost model uses the input data. 

11.2.1 Model Site Development 

The Agency used a model-site approach to estimate costs for the waterdischarging sites in the MP&M Point Source Category. A model site is an operating MP&M 

survey site whose regulatory status, and unit operation and treatment information were used as 

input to the cost model. EPA selected a site-by-site model approach to estimate compliance 

costs, as opposed to a more generalized approach, to better characterize the variability of both 

process water and wastewater discharges in the MP&M industry. EPA selected 915 model sites 

from the 1,563 sites returning surveys. EPA excluded sites if: 

� The site’s operations did not fall within the scope of this rulemaking; 

� The site did not discharge wastewater (treated or untreated) to either a 

surface water or publicly owned treatment works (POTW); or 

� The site did not supply sufficient technical data to estimate compliance 

costs and pollutant loading reductions associated with the technology 

options. 

Each of the 915 facilities is considered a “model” facility for two reasons. First, 

because only a portion of the MP&M universe was surveyed, each facility represents a larger 

number of similar facilities in the overall industry population, as determined by its statistical 

survey weight. Section 3.0 discusses the development of survey weights. The surveyed sites 

represent an estimated industry population of more than 44,000 sites that discharge either directly 

to surface waters or indirectly through a POTW. Second, because only a portion of the MP&M 

universe was sampled, EPA used its sampling data to model an aggregated influent to treatment 

concentration for each survey site based on the survey subcategory and the unit operations the 

site performs. Section 12.0 discusses the use of unit operation sampling data. Additionally, the 

11-6

11.0 - Costs of Technology Bases for Regulations 

Agency made engineering assumptions based on national information from standard engineering 

costing publications, equipment vendors, and industry-wide data. Thus, for any given model site, 

the estimated costs and loads may deviate from those that the site would actually incur. 

However, EPA considers the compliance costs to be accurate when evaluated on an industrywide, aggregate basis. 

11.2.2 Wastewater Streams and Flow Rates 

EPA used wastewater discharge parameters (e.g., production rates, flow, and 

operation schedule) to calculate wastewater generation and discharge rates. The cost model uses 

these flow rates to estimate the capacity of treatment units needed for each wastewater stream. 

Using information from survey responses, follow-up letters, and phone calls, EPA first classified 

each process wastewater stream by the type of unit operation generating the wastewater (e.g., 

machining, electroplating, acid treatment). For each unit operation, EPA then determined 

production rate, operating schedule, wastewater discharge flow rate, and discharge destination. 

Some sites provided all the information needed for each wastewater stream, but others did not. 

EPA determined the wastewater discharge parameters as described below: 

� Production rate. In survey responses, sites reported production rates in 

surface area processed, mass of metal removed, or air flow rate, depending 

on the unit operation. Production expressed in terms of surface area 

represented surface finishing or cleaning operations; mass of metal 

removed represented metal removal operations such as machining and 

grinding; and air flow rate represented air pollution control operations. 

For blank responses, EPA statistically imputed production rates using 

other data provided in the site’s survey or by using data for similar unit 

operations reported in other MP&M surveys. The general methodology as 

well as specific production calculations can be found in DCN 36200 in 

Section 28.2 of the rulemaking record. 

� Operating schedule. EPA used survey responses to represent the 

operating rate (hours per day (hpd) and days per year (dpy)) of each unit 

operation. For blank responses, EPA used the following: 

- The maximum hpd and dpy reported by the site for other unit 

operations, if reported by the site, or 

- The survey response for wastewater treatment system operating 

schedule, if the site provided a wastewater treatment operation 

schedule, or 

- 8 hpd and 260 dpy. This estimate represents the median work 

schedule for MP&M sites. 

11-7

11.0 - Costs of Technology Bases for Regulations 

� Wastewater discharge flow rate. For each process wastewater stream, 

most sites reported the total wastewater discharge flow rate from the unit 

operation and associated rinses. For sites that reported performing a unit 

operation but did not report a discharge flow rate, EPA statistically 

imputed wastewater flow rates using other data provided in the site’s 

survey or by using data for similar unit operations reported in other 

MP&M surveys. The general methodology as well as specific calculations 

for sites’ wastewater flow rates can be found in DCN 36200, in Section 

28.2 of the rulemaking record. 

� Discharge destination. EPA used survey responses to determine the 

discharge destination of each unit operation (surface water, POTW, no 

discharge, contract haul, or other alternatives) and the level of treatment 

prior to discharge (none, pollution prevention, chemical precipitation, 

sedimentation, etc.). In many cases, a site had multiple discharge 

destinations. EPA assumed no costs would be incurred at baseline for 

wastewater streams not discharged to POTWs or surface waters (i.e., those 

contracted for off-site disposal, deep-well injected, discharged to septic 

systems, reused on site, or otherwise not discharged (recycled, evaporated, 

etc.)). For sites that did not report a discharge destination for some or all 

operations, EPA used other MP&M survey information (e.g., types of 

discharge permits, discharge destination of other unit operations, process 

flow diagrams) to determine the stream discharge destination. For details 

on determination of site discharge destination, see Section 24.6.1 of the 

rulemaking record, DCNs 17881, 17825, and 17826. 

EPA then used the completed wastewater discharge information to create the first 

of three cost model input databases, Model Site Profile 1 (MSP1). Table 11-3 summarizes the 

information contain in MSP1. 

Table 11-3 

Information Contained in MSP1 

Field Name Description 

SiteID Random Site Identification Number assigned by EPA. 

UPNum Unit operation number as reported in the survey. (See Section 4.0 for a list of unit operations 

performed at MP&M facilities.) 

UPExt Unit operation extension. Each unique unit operation was given a new extension (e.g., electroless 

nickel plating might be UP20-1 and electroless copper plating might be UP20-2). 

UPRinse Unit operation rinse indicator. "0" designates a unit operation, "R" designates a unit operation 

rinse. 

11-8

11.0 - Costs of Technology Bases for Regulations 

Table 11-3 (Continued) 

Field Name Description 

StreamID A consolidation of the fields UPNum, UPRinse, and UPExt used by the cost model 

(UPNum+UPRinse"-"UPExt). 

SiteDest Overall site wastewater discharge destination as determined by the survey. 

Weights Industry Weighting Factor; this number indicates how many sites the survey represents on a 

national basis (see Section 3.0 for more information). 

FLOW Unit operation discharge flow in gallons per hour. 

PROD Unit operation production in PNP per hour. 

PNP Production-normalizing parameter; standard cubic feet per minute, square feet, or pounds of 

metal removed depending on the unit operation. 

PNF Production-normalized flow, equivalent to FLOW/PROD. 

HPD Hours per day that the unit operation operates. 

DPY Days per year that the unit operation operates. 

TANKVOL Unit operation tank volume in gallons. 

NUMUNITS Number of individual units represented by the unit operation (e.g., 30 machines performing the 

same operation, operating the same hours and days, and using the same process chemicals would 

be represented by one unit operation in MSP1 but would have a numunits of 30). 

BASEMET Base metal of the part on which the operation is being performed. 

METAPPL Metal being applied by the unit operation (where appropriate). 

DEST Stream discharge destination as determined by the detailed unit operation information. 

RinseCode Rinse water code used to determine the level of pollution prevention currently in place at the site. 

Refer to Section 5.3.2.2 of the rulemaking record, DCN 15773, for specific code definitions. 

Equipment 

Code 

Equipment code used to determine the amount of equipment currently in place at the site. Refer 

to pollution prevention documentation for specific code definitions. 

MCTIP Indication of whether the stream has machine coolant treatment in place (yes/no). 

IXTIP Indication of whether the stream has ion exchange treatment in place (yes/no). 

PCTIP Indication of whether the stream has paint curtain treatment in place (yes/no). 

11.2.3 Wastewater Pollutant Concentrations 

EPA developed pollutant concentrations for the model sites’ wastewater streams. 

The cost model tracks two concentrations for each wastewater stream: the baseline pollutant 

concentration and the post-compliance pollutant concentration. The baseline pollutant 

concentration represents what the site currently discharges. The post-compliance pollutant 

concentration represents what the site would discharge after installing the regulatory option 

technology. 

EPA assigned each wastewater stream a baseline pollutant concentration for each 

pollutant of concern (POC) in the second input database named MSP2. The cost model used this 

11-9

11.0 - Costs of Technology Bases for Regulations 

information to calculate both costs and pollutant loadings. The remainder of this section 

describes how the cost model used pollutant concentration data to estimate costs. Section 12.0 

discusses how the cost model used these data to estimate pollutant loadings. Table 11-4 

summarizes the information contained in MSP2. 

Table 11-4 

Information Contained in MSP2 

Field Name Description 

SiteID Random Site Identification Number assigned by EPA. 

StreamID A consolidation of the fields UPNum, UPRinse, and UPExt used by the cost model 

(UPNum+UPRinse"-"UPExt). 

PollCode Pollutant identification code (e.g., CU, NA, TS). Refer to analytical data documentation 

(Section 5.3.2.2 of the rulemaking record, DCN 15773) for specific code definitions. 

CHEM_NAM Chemical Name (e.g., copper, sodium, total suspended solids). Refer to analytical data 

documentation for specific code definitions. 

PollConc Pollutant concentration as defined through analytical data (mg/L). Refer to Section 12.0 for 

concentration development information. 

11.2.4 Technology in Place 

The term “technology in place” refers to those treatment technologies installed 

and operating at a model site. EPA recognizes the importance of identifying which wastewater 

streams were already being treated. For example, sites with technology in place that met or 

exceeded the option technology would incur no additional costs, and sites with some technology 

in place would need only parts of the option technology. Sites with technology in place that met 

or exceeded the option technology but did not treat all of the required streams with this 

technology would incur costs to increase capacity, if required. Therefore, EPA identified 

technology in place from survey responses, which documented the technology in place at the 

time of the survey response. EPA’s surveys cover two base years: 1989 and 1996. Because EPA 

has two base years for this industry, where EPA received updated TIP information up to the later 

base year of 1996, EPA incorporated this updated information in its analyses. The cost model 

used these data to determine what components of the option technology a site would need, as in 

Example 11-1 at the end of this section. 

The regulatory options include two types of wastewater treatment: (1) in-process 

pollution prevention and source reduction (pollution prevention) and (2) end of pipe. EPA 

determined the technologies in place for all unit operations, both pollution prevention and end of 

pipe; however, some sites did not provide information on the pollution prevention technology in 

place. The following paragraphs describe in detail how EPA determined pollution prevention 

technologies in place for these sites. 

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11.0 - Costs of Technology Bases for Regulations 

Determination of Pollution Prevention Technology In Place 

Although both the 1989 and 1996 MP&M Detailed Surveys requested detailed 

information on end-of-pipe treatment in place, only the 1996 MP&M Detailed Survey requested 

information about a site’s in-process pollution prevention technologies. Where available, EPA 

determined pollution prevention technology in place based on survey responses (e.g., for all 1996 

survey respondents). For other model sites, the Agency determined pollution prevention 

technology in place based on other survey information. For example, EPA examined the model 

site’s production-normalized flow rate (PNF). The PNF is the volume of wastewater generated 

per unit of production, as described in the following equation: 

F L O W P N F = (11-1) P R O D 

where: 

PNF = Production-normalized flow, gallons per ton; 

FLOW = Annual wastewater discharge, gallons per year; and 

PROD = Annual production, tons per year. 

Generally, the less wastewater generated per volume of production, the better the 

pollution prevention technology in place. Therefore, if the site PNF was below the median PNF 

calculated for the industry for that pollution prevention technology, then EPA assumed the site 

had the pollution prevention technology in place. For example, if a 1989 survey site reported a 

machining wastewater stream with a PNF below the median PNF for centrifugation and 

pasteurization of machining coolants, then the Agency assumed that the model site had a 

machining coolant regeneration/recycling system in place. The median PNFs estimated for each 

technology are detailed in Section 24.6.1 of the rulemaking record, DCN 17885. 

Determination of Rinse Scheme Technology In Place 

EPA used a similar method to determine which sites had efficient rinse schemes. 

For unit operations without the option rinse technology in place, EPA estimated costs to install 

and operate a two-stage countercurrent cascade rinse. EPA used the following parameters in 

designing rinse technology upgrades: 

� Rinse technology in place. EPA determined which of the following rinse 

technologies sites had in place: 

- Two overflow rinse tanks,


- One overflow rinse tank,


- One stagnant tank followed by one overflow tank,


- One spray rinse, or


- Two-stage countercurrent cascade rinsing.


11-11

11.0 - Costs of Technology Bases for Regulations 

For sites that did not provide information on their rinse scheme, EPA 

classified their rinse type based on the PNF for the industry. First EPA 

calculated site-specific PNFs for all rinses with data. Next, the Agency 

calculated the median industry PNFs for each rinse type. Finally, EPA 

assigned each unknown stream a rinse type corresponding to the stream’s 

PNF. 

For more information on the median PNF calculations and the PNFs 

associated with each rinse type, see Section 24.6.1 of the rulemaking 

record, DCN 17885. 

� Tank volume. The cost model uses unit operation tank volume as a 

design parameter for countercurrent cascade rinsing, but the Agency did 

not request this information in the surveys. EPA estimated additional tank 

volume needed based on the annual discharge flow rate. 

EPA then estimated what new pollution prevention equipment a site would need 

to meet the regulatory option. Sites with countercurrent cascade rinsing in place would not 

require rinse upgrades. Sites with parts of countercurrent cascade rinsing, such as tanks but not 

enough piping, were allocated costs for the piping and pumps needed. Additional information on 

the rinse flow reduction methodology can be found in Section 24.6.1 of the rulemaking record, 

DCN 17885. Section 11.3.3 also discusses flow reduction methodology. 

Determination of End-of-Pipe Technologies in Place 

EPA reviewed survey data for each model site to assess the end-of-pipe 

technologies in place (e.g., chemical reduction of chromium, sludge pressure filtration). EPA 

found some technologies in place that were not part of the regulatory options but achieve 

removals equivalent to the option technology. For example, the Agency considered vacuum 

filtration equivalent to pressure filtration for sludge dewatering. EPA also assumed that some 

sedimentation and oil treatment systems qualified as treatment in place for multiple options. For 

example, if a site had microfiltration in place for solids removal, EPA considered that equivalent 

treatment for either microfiltration or clarification. If a site had a clarifier in place, EPA 

considered it equivalent for clarification, but not for microfiltration. Table 11-5 lists the 

technologies that EPA considered equivalent to the option technologies. EPA also found 

technologies that it did not consider equivalent to option technologies. For example, EPA did 

not consider oil/water separation equivalent to dissolved air flotation in the advanced technology 

options. Conversely, the Agency considered dissolved air flotation to achieve equivalent or 

better pollutant removals than oil/water separation. EPA assumed that sites specifying only 

chemical precipitation also had a clarifier and vice versa. In addition, the Agency assumed sites 

with treatment systems in place have the associated chemical feed systems. Assumptions 

regarding treatment technologies in place at each model site are discussed in detail in Section 6.5, 

DCN 15799, and Section 24.6.1, DCN 17888, of the rulemaking record. 

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11.0 - Costs of Technology Bases for Regulations 

Table 11-5 	

Treatment Technologies Considered Equivalent to the Option Technologies	

Technology Specified by Option 

Technologies Considered Equivalent or Better to the 

Option Technologies 

Chelated metals treatment Chelated metals treatment 

Chemical emulsion breaking and gravity 

oil/water separation 

Chemical emulsion breaking and gravity oil/water separation 

Chemical emulsion breaking and gravity flotation 

Dissolved air flotation 

General oil water separationa 

Ultrafiltration 

Chemical precipitation and 

sedimentation 

Chemical precipitation 

Sites without chemical precipitation and 

(1) with ion exchange were assumed to have technology equivalent to 

chemical precipitation and clarification 

(2) with dissolved air flotation assumed to have technology equivalent 

to given chemical precipitation and clarificationa 

(3) with pH adjustment and sludge dewatering/filter press were 

assumed to have technology equivalent to chemical precipitation, 

clarification, and sludge dewatering/filter pressa 

Chromium reduction Chromium reduction 

Clarification Clarification 

Microfiltration 

Dissolved air flotation (where no other chemical precipitation is 

present)a 

Cyanide reduction Cyanide reduction 

Ion exchange 

Dissolved air flotation Dissolved air flotation 

Ultrafiltration 

Filter press Filter press 

Vacuum filtration 

Microfiltration for solids removal Microfiltration 

Multimedia filtration Multimedia filtration 

Sludge dewatering Sludge dewatering 

Gravity thickener 

Sludge settling tank 

Ultrafiltration for oil removal Ultrafiltration for oil removal 

a

These technologies are considered equivalent only for the purpose of defining treatment in place, not as a proven 

method of meeting the final limits. 

11-13

11.0 - Costs of Technology Bases for Regulations 

EPA also used survey data to determine the capacity of the end-of-pipe 

technologies in place at the model sites for the following parameters: 

� Operating schedule. EPA used the operating schedule (hpd and dpy) for 

each treatment unit supplied by sites. For blank responses, EPA 

determined the schedule using the following: 

- The maximum hpd and dpy reported for other treatment units, 

- The maximum hpd and dpy reported for the unit operations, if all 

hpd and dpy responses for all treatment units were blank, 

- The maximum hpd and dpy reported by the site for other unit 

operations associated with other treatment units, or 

- 8 hpd and 260 dpy, if all hpd and dpy survey responses were blank 

for unit operations and treatment units. 

� Wastewater streams treated. For blank responses, EPA determined 

which wastewater streams were treated by the technology in place using 

survey process flow diagrams or survey responses regarding the 

destination of individual process wastewater streams. If this information 

was not provided, EPA used the cost model logic described in Section 

11.3 to help assign streams to technologies (e.g., EPA assumed that 

cyanide-bearing streams were treated through cyanide destruction, if the 

site currently had it in place). 

EPA used the operating schedule and wastewater stream flows treated by the 

technology to define the capacity needed for each technology using the following equation: 

Q V × SA = (11-2) H LR 

where: 

V = Volume of tank needed, gallons;


SA = Surface area of tank, gallons per foot;


Q = Discharge flow, gallon per minute; and


HLR = Hydraulic loading rate. EPA set the HLR to 1,000 gallons per


square foot per day. 

The Agency determined design capacity from one of two flows: the surveyprovided design capacity flow (when available) or the model design capacity flow as derived 

from the 122 percent of baseline flow. The methodology for calculating the model flow is 

11-14

11.0 - Costs of Technology Bases for Regulations 

discussed in detail in Section 11.3.4. EPA also accounted for those sites that may need to 

increase wastewater treatment capacity as a result of the process changes associated with some of 

EPA’s technology options. Section 11.3.4 presents how EPA accounted for baseline end-of-pipe 

technologies with insufficient capacity. Also, more details on capacity calculations are in 

Section 6.7, DCN 15902, and Section 24.6.1, DCN 17903, of the rulemaking record. All streamby-stream treatment-in-place information was then incorporated into the final input database 

MSP3. Table 11-6 summarizes the information contained in MSP3. 

Table 11-6 

Information Contained in MSP3 

Field Name Description 

SiteID Sited Identification Number assigned by EPA. 

UPNum Unit operation number as reported in the survey. 

UPPrefix Identifier that indicates if the UPNum refers to a unit operation, in-process pollution prevention 

operation, or treatment unit. EPA used this field to aid in the creation of MSP3 (e.g., UP or TU). 

UPExt Unit operation extension. Each unit operation was given a new extension (e.g., electroless nickel 

plating might be UP20-1 and electroless copper plating might be UP20-2). 

OldExt Field used in the creation of MSP1 and MSP3. 

UPSuffix Unit operation rinse indicator. "0" designates a unit operation, "R" designates a unit operation 

rinse. 

StreamID A consolidation of the fields UPNum, UPRinse, and UPExt used by the cost model 

(UPNum+UPRinse"-"UPExt). 

MODULE Indicates which treatment units the site currently has in place. 

HPD Hours per day that the treatment unit operates. 

DPY Days per year that the treatment unit operates. 

SITEDCF The design capacity flow reported by the site in survey data (gph). 

DCF The design capacity flow populated during cost model operation. This is equivalent to the larger 

of the following: the sitedcf or a minimum dcf calculated in the cost model. Refer to cost model 

documentation (Section 24.6.1, DCN 17890) for complete DCF creation information (gph). 

11.2.4.1 Baseline Model Runs 

The baseline run simulated the current treatment practices at each model site. The 

cost model uses baseline costs to determine the incremental costs for each regulatory option. 

EPA first performed a baseline run of the cost model to determine the following parameters: 

� Estimated baseline O&M costs incurred by sites in 2001 dollars; 

� Estimated baseline non-water quality impacts such as electricity usage, 

sludge generation, and waste oil generation; 

11-15

11.0 - Costs of Technology Bases for Regulations 

� Estimated baseline pollutant effluent concentrations (see Section 12.0); 

and 

� Capacity flow rate of each wastewater treatment technology in place. 

11.2.4.2 Post-Compliance Model Runs 

Following the baseline model run, EPA then ran a post-compliance cost model 

run for each regulatory option. Each cost model run calculated the following values: 

� Incremental capital investment costs incurred by sites in 2001 dollars; 

� O&M costs incurred by sites in 2001 dollars; 

� Non-water quality impacts such as electricity usage, sludge operation, and 

waste oil generation; and 

� Pollutant loadings discharged after installation of the option technology 

(see Section 12.0). 

EPA calculated incremental O&M costs as the difference between baseline and 

post-compliance, using the following equation: 

O&M CostsIncremental = O&M CostsTreated - O&M CostsBaseline (11-3) 

EPA used the same methodology to calculate incremental values for non-water quality impacts 

and pollutant loadings. 

11.2.4.3 New Source Model Runs 

EPA also ran new source cost model runs for the General Metals, Metal Finishing 

Job Shops, Non-Chromium Anodizing, Printed Wiring Board, and Oily Wastes Subcategories. 

These runs estimated the costs a new source would incur in meeting the new source standards 

considered for Part 438. Model sites were used to calculate total construction and operating costs 

associated with a brand new treatment system consisting of the appropriate option technology. 

Each cost model run calculated the following values: 

� Total, rather than incremental, capital investment costs incurred by sites in 

2001; 

� Total, rather than incremental, O&M costs incurred by sites in 2001 

dollars; 

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11.0 - Costs of Technology Bases for Regulations 

� Total, rather than incremental, monitoring costs incurred by sites in 2001 

dollars; 

� Non-water quality impacts such as electricity usage, sludge operation, and 

waste oil generation; and 

� Pollutant loadings discharged after installation of the option technology 

(see Section 12.0). 

The model estimated total costs for new sources to meet the considered 438 

limitations as follows: 

Subcategorya 

Discharge 

Destination 

Number of 

MP&M Sites 

Capital Costs 

($2001) 

Annual Costs 

($2001) 

Annualized 

Costs ($2001) 

General Metals Direct 794 116,844,985 310,919,560 324,321,680 

Indirect 10,307 1,851,638,823 2,268,371,865 2,480,754,838 

Metal Finishing Job 

Shops 

Direct 12 5,546,098 2,612,444 3,248,581 

Indirect 1,542 372,340,073 276,027,559 318,734,965 

Non-Chromium 

Anodizing 

Direct None Identified 

Indirect 122 76,369,114 112,525,473 121,285,010 

Printed Wiring Board Direct 8 3,128,633 2,697,791 3,056,645 

Indirect 818 230,533,415 255,151,103 281,593,286 

Oily Wastes Direct 2,585 79,678,368 101,830,335 110,969,444 

Indirect 26,608 575,295,361 1,629,178,524 1,695,164,902 

a

EPA did not perform new source cost model runs for the Railroad Line Maintenance or Shipbuilding Dry Dock 

Subcategories because, as discussed in the preamble to the final rule, EPA determined that national regulation of 

discharges in these subcategories is unwarranted at this time. 

Note that for metal-bearing subcategories, EPA then costed new sources to 

operate two separate chemical precipitation and solids separation steps in series. This was done 

to address concerns raised by commentors that single-stage precipitation and solids separation 

may not achieve sufficient removals for wastewaters that contain significant concentrations of a 

wide variety of metals that precipitate at disparate pH ranges. To calculate the addition of a 

second stage of treatment, EPA doubled the original treatment costs. 

11.3 General Methodology for Estimating Costs of Treatment Technologies 

This subsection discusses the methodology for estimating costs, including the 

components of cost (Section 11.3.1), the sources and standardization of cost data (Section 

11.3.2), the cost model (Section 11.3.3), and assumptions made during the costing effort (Section 

11.3.4). 

11-17

11.0 - Costs of Technology Bases for Regulations 

11.3.1 Components of Cost 

The components of the capital and annual costs and the terminology used in 

developing these costs are presented below. 

Capital Investment Costs 

The capital investment costs consist of two major components: direct capital 

costs and indirect capital costs. The direct capital costs include: 

� Purchased equipment cost, including ancillary equipment (e.g., piping, 

valves, controllers); 

� Delivery cost (based on the equipment weight and a shipping distance of 

500 miles); and 

� Installation/construction cost (including labor and site work). 

EPA derived the direct components of the total capital cost separately for each 

treatment unit or pollution prevention technology. When possible, EPA obtained costs for 

various sizes of preassembled, skid-mounted treatment units from equipment vendors. If costs 

for these units were not available, EPA obtained catalog prices for individual system components 

(e.g., pumps, tanks, feed systems) and summed these prices to estimate the cost for the treatment 

unit. 

Indirect capital costs consist of secondary containment, engineering, contingency, 

and contractor fees. These costs together with the direct capital costs form the total capital 

investment. EPA estimates the indirect costs as percentages of the total direct capital cost, as 

shown in Table 11-7. 

Annual Costs 

Annual costs include the following: 

� Raw material costs - Chemicals and other materials used in the treatment 

processes (e.g., sodium hydroxide, sulfuric acid, sodium hypochlorite); 

� Operating labor and material costs - The labor and materials directly 

associated with operation of the process equipment; 

� Maintenance labor and material costs - The labor and materials required 

for repair and routine maintenance of the equipment; 

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11.0 - Costs of Technology Bases for Regulations 

� Energy costs - Calculated based on total energy requirements (in kiloWatt 

hours (kW-hrs)); and 

� Monitoring and analytical costs - The periodic sampling and analysis of 

wastewater effluent samples to ensure that discharge limitations are being 

met. 

Table 11-7	

Components of Total Capital Investment	

Item 

Number Item Cost Source 

1 Equipment capital costs including 

required accessories 

Total equipment cost MP&M cost model capital 

cost curves 

2 Site work, including demolition, 

concrete repair, and build out 

3% of total equipment cost Attachment 1 

(DCN 16027, Section 6.7.1) 

3 Shipping cost, based on weight of 

equipment and 500-mile shipping radius 

Technology-specific cost, 

see individual cost module 

Attachment 2 

(DCN 16027, Section 6.7.1) 

4 Installation, based on estimated number 

of hours for each technology at a rate of 

$29.67/hour 

Technology-specific cost, 

see individual cost module 

MP&M cost modules 

5 Direct capital cost Sum of items 1 through 4 

6 Engineering/administrative and legal 

costs 

10% of item 5 Attachment 1 

(DCN 16027, Section 6.7.1) 

7 Secondary containment/land costs 10% of item 5 Attachment 3 

(DCN 16027, Section 6.7.1) 

8 Total plant cost Sum of items 5 through 7 

9 Contingency 15% of item 8 Attachment 1 

(DCN 16027, Section 6.7.1) 

10 Contractor’s fee 5% of item 8 Attachment 1 

(DCN 16027, Section 6.7.1) 

11 Total capital investment Sum of items 8 through 10 

11.3.1.1 Total Annualized Costs 

EPA calculated total annualized costs (TAC) from the capital and annual costs. 

The Agency assumed a 7-percent discount rate over an estimated 15-year equipment life, using 

the following equation: 

Annualized Cost = (Incremental Capital Cost) × 0.1147 + (Incremental Annual Cost)(11-4) 

11-19

11.0 - Costs of Technology Bases for Regulations 

11.3.2 Sources and Standardization of Cost Data 

EPA obtained capital and annual cost data for the technologies that constitute 

EPA’s technology options (see Section 9.0) from equipment vendors, literature, and MP&M 

sites. The Agency used specific data from the 1989 and 1996 MP&M Detailed Surveys 

whenever possible; however, the required types of data were often either not collected or not 

supplied by the sites. The major sources of capital cost data were equipment vendors, while the 

literature sources provided most of the annual cost information. 

� Capital Equipment. EPA obtained information on capital equipment 

from vendors in 1998; specific cost estimates for technologies are included 

in Section 6.7.1 of the rulemaking record. 

� Chemicals. EPA used the Chemical Marketing Reporter from December 

1997 to obtain chemical prices (2). A list is in Section 6.7.1 of the 

rulemaking record, DCN 15890. 

� Water and Sewer Costs. EPA based water and sewer use prices on 

average data collected through an EPA Internet search of various public 

utilities located throughout the United States for years ranging from 1996 

to 1999. The average water and sewer use charges were $2.03 per 1,000 

gallons and $2.25 per 1,000 gallons, respectively. The results of the 

Internet search can be found in Section 6.7.1 of the rulemaking record, 

DCN 15890. 

� Energy. EPA used average electricity prices from the U.S. Department of 

Energy’s Energy Information Administration. The average electrical cost 

to industrial users from 1994 to 1996 was $0.047 per kW-hr (see Section 

6.7.1 of the rulemaking record, DCN 15890). 

� Labor. EPA used a labor rate of $29.67 per hour to convert the labor 

requirements of each technology into annual costs. The Agency obtained 

the base labor rate from the Monthly Labor Review, which is published by 

the U.S. Bureau of Labor Statistics of the U.S. Department of Labor. 

Excluding the maximum and minimum values, EPA used the largest 

remaining monthly value for 1997 for production labor in the fabricated 

metals industry, $12.90 per hour, as a conservative estimate. The Agency 

added 15 percent of the base labor rate for supervision and 100 percent for 

overhead to obtain the labor rate of $29.67 per hour (3). See Section 6.7.1 

of the rulemaking record, DCN 15890. 

� Off-Site Treatment/Disposal. EPA estimated average costs of 

contracting for off-site waste treatment/disposal using data from the 1996 

MP&M Detailed and Screener Surveys, as discussed in Section 11.4.4. 

11-20

11.0 - Costs of Technology Bases for Regulations 

The Agency estimated costs to dispose of RCRA hazardous metal 

hydroxide sludge from Pollution Prevention and Control Technology for 

Plating Operations (4). Table 11-8 presents the treatment/disposal costs 

for various waste types. See Section 6.7.1 of the rulemaking record, DCN 

16023. 

� Monitoring Costs. MP&M effluent monitoring costs were developed 

based on sampling frequency, the cost per analysis, and the labor to collect 

the samples. Monitoring costs vary depending on the current regulatory 

status of the facility. The following subsections describe the MP&M 

monitoring frequency requirements and the estimated incremental 

monitoring costs for each MP&M subcategory. 

Table 11-8 

Costs for Contracted Off-Site Treatment/Disposal of Various Waste Types 

Waste Type Cost ($/gallon) 

RCRA hazardous nonhazardous paint sludge 3.70 

RCRA hazardous metal hydroxide sludge (3) 1.95 

RCRA nonhazardous oil 0.86 

Solvent (paint and paint stripping waste) 2.85 

Oily wastewater 1.33 

General metal-bearing wastewater 2.00 

Cyanide-bearing wastewater 5.64 

Hexavalent chromium-bearing wastewater 3.51 

Chelated metal-bearing wastewater 1.40 

Source: 1996 MP&M Detailed and Screener Surveys. 

EPA standardized capital and annual cost data to 1996 dollars (the most current 

year for which EPA collected survey data). Final industry cost estimate numbers are then 

converted to 2001 dollars using the Engineering News-Record Construction Cost Index. For 

cases where EPA’s information is not representative of 1996, EPA adjusted the cost estimates 

using RS Means Building Construction Historical Costs as shown in Table 11-9 (see Section 

6.7.1 of the rulemaking record, DCN 15890). 

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11.0 - Costs of Technology Bases for Regulations 

Table 11-9	

RS Means Building Construction Historical Cost Indexes	

Year Index 

1989 92.1 

1990 94.3 

1991 96.8 

1992 99.4 

1993 101.7 

1994 104.4 

1995 107.6 

1996 110.2 

1997 112.8 

1998 114.4 

Source: Historical Cost Indexes, RS Means Building Construction Cost Data, 

56th Annual Edition, 1998, page 594 (1). 

Monitoring Frequency for Metal-Bearing Subcategories 

When developing costs for the Part 438 effluent limits considered for the metalbearing subcategories, EPA considered a monitoring frequency of once per week for regulated 

pollutants. EPA calculated the costs for the Part 438 limitations assuming the monitoring 

frequencies listed in Table 11-10. See Section 24.6.1 of the rulemaking record, DCN 17911. 

Sampling and Analysis Costs 

EPA developed sampling labor and equipment requirements based on its 

experience gained during the MP&M sampling episodes. The Agency determined laboratory 

analysis costs for each regulated pollutant by contacting PEL Laboratories in Tampa, Florida. 

Using the monitoring frequency, labor hours to collect samples, the loaded labor rate 

($29.67/hour), and the cost per analysis, EPA estimated the annual monitoring costs for various 

facilities. 

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11.0 - Costs of Technology Bases for Regulations 

Table 11-10 

Monitoring Frequencies Used to Develop Part 438 Limitations Considered 

for Metal-Bearing Subcategories 

Regulated Pollutant Sample Type Samples/week Samples/month Samples/year 

Cadmium Composite 1 4 48 

Chromium Composite 1 4 48 

Copper Composite 1 4 48 

Lead Composite 1 4 48 

Nickel Composite 1 4 48 

Silver Composite 1 4 48 

Tin Composite 1 4 48 

Zinc Composite 1 4 48 

Cyanide (total) Composite 1 4 48 

Oil and grease (as HEM) Grab 4 12 192 

pH Composite 1 4 48 

Total Toxic Organic (TTO) 

parameter

a 

Grab 0 1 12 

a

Sum of volatile organics, semivolatile organics, pesticides and PCBs. 

Incremental monitoring costs for metal-bearing MP&M facilities depended on 

their current regulatory status. Incremental costs for facilities currently regulated by Part 433 or 

assumed to be meeting Part 433 (e.g., direct-discharging facilities in the General Metals 

Subcategory) to comply with the limits considered for existing and new source Part 438 resulted 

from: 

� Adding tin to the list of regulated pollutants; 

� Lowering the effluent limit for lead, which requires analysis by graphite 

furnace atomic adsorption ($28/sample) rather than inductively coupled 

plasma ($20/sample); and 

� Increasing the number of samples for oil and grease from one to four 

during each sampling event. 

Incremental sampling labor costs result from the need to collect four oil and 

grease samples rather than one during the facility’s daily processing period. The annual 

incremental monitoring cost for a Part 433 facility to comply with the limits considered for Part 

438 were approximately $22,000 for the metal-bearing subcategories (see Section 24.6.1 of the 

rulemaking record, DCN 17911). These incremental monitoring costs are conservative (e.g., 

some Part 433 facilities may be currently collecting four oil and grease grab samples per 

monitoring day and some that generate oily waste may have either implemented an Organics 

Management Plan or are already collecting 12 TTO samples per year). 

11-23

11.0 - Costs of Technology Bases for Regulations 

Costs for new source facilities (not including existing facilities that become new 

source facilities) result from the purchase or rental of sampling equipment, sampling labor, and 

laboratory analysis. The monitoring and analytical cost for these new source facilities to comply 

with the considered effluent limits was $41,000 for the metal-bearing subcategories (see Section 

24.6.1 of the rulemaking record, DCN 17911). 

Monitoring Frequency for Oil-Bearing Subcategories 

EPA evaluated monitoring frequency separately for the Oily Wastes, Railroad 

Line Maintenance, and Shipbuilding Dry Dock Subcategories due to the high percentage of 

survey- and comment-supplied DMR sampling data in each of these subcategories. One hundred 

percent of the direct discharging railroad line maintenance facilities supplied sampling data and 

some associated sampling frequency information. Ninety-two percent of the direct discharging 

oily wastes facilities, with treatment in place, supplied sampling data and some associated 

sampling frequency information. Fifty percent of the shipbuilding dry dock facilities supplied 

sampling data and some associated sampling frequency information. 

Direct discharging MP&M facilities in the Oily Wastes Subcategory will be 

required to monitor their discharges for total suspended solids (TSS) and oil and grease. Based 

on the supplied information, for the Part 438 limitations, EPA calculated incremental monitoring 

costs assuming all direct discharging facilities are currently analyzing at least one TSS and oil 

and grease sample per month. Therefore, incremental monitoring costs for these facilities is 

zero1

. Monitoring frequencies are determined by the permit writer and must be a minimum of 

once per year. The monitoring frequency specified in MP&M National Pollutant Discharge 

Elimination System (NPDES) permits will vary depending upon the size of the facility, potential 

impacts on receiving waters, compliance history, and other factors, including monitoring policies 

or regulations required by permit authorities. EPA encourages permit writers to require all 

facilities subject to the Part 438 limitations to collect a minimum of one TSS and oil and grease 

sample per month. Facilities may monitor more frequently than specified in their permits; 

however, the results must be reported in accordance with Part 122.41(1)(4)(ii) for direct 

dischargers. 

1

Based on the information in its database, EPA concludes most facilities currently collect one sample per month. 

During EPA sampling events, EPA collected four grab samples at each sampling point each day. These samples 

were analyzed individually with the results composited mathematically to obtain a single daily concentration for each 

pollutant at each sampling point. While the final limitations are based on these composited values, the analytical 

method allows a facility to composite multiple grab samples prior to analysis. Therefore, analytical costs should 

remain constant for these facilities even if permit writers require them to collect a composite, rather than grab 

sample. 

11-24 
11.0 - Costs of Technology Bases for Regulations 

11.3.3 Development of the Cost Model 

The cost model consists of the following programming components: 

� Model shell; 

� Model drivers; 

� Data storage files; and 

� Technology modules. 

The model shell includes a program that creates various menus and user interfaces 

that accepts user inputs and passes them to the appropriate memory storage areas. The model 

drivers are programs that access technology modules in the proper order for each option and 

process model-generated data. Data storage files are databases that contain cost model input and 

output data. Information typically stored in data storage files includes: 

� Flow, production, and operating data associated with each wastewater 

stream; 

� Pollutant concentrations associated with each wastewater stream; and 

� Site-specific data regarding existing technologies in place (discussed in 

Section 11.2.4). 

Technology modules are programs that calculate costs and pollutant loadings for a 

particular pollution control technology. EPA developed cost modules for the pollution 

prevention and end-of-pipe technologies included in the regulatory options for the MP&M 

industry. 

The technology drivers perform the following functions for each technology 

costed for a site (if applicable): 

� Locate and open necessary input data files;


� Store input data entered by the user;


� Open and run the appropriate technology modules; and


� Calculate and track model outputs.


Table 11-11 lists the treatment technology modules that are used in the cost 

model. Section 11.5 discusses the technology modules. 

In the context of the MP&M cost program, “model” refers to the overall computer 

program and “module” refers to a computer subroutine that generates costs and pollutant 

loadings for a specific in-process or end-of-pipe technology or practice (e.g., chemical 

precipitation and sedimentation, contract hauling). EPA adapted some modules from previous 

11-25

11.0 - Costs of Technology Bases for Regulations 

EPA rulemaking efforts for the metals industry and developed others specifically for this 

rulemaking effort. 

Table 11-11 

Wastewater Treatment Technologies and Source Reduction 

and Recycling Practices for Which EPA Developed Cost Modules 

In-Process Technologies and Practices End-Of-Pipe Technologies and Practices 

Countercurrent cascade rinsing 

Centrifugation and pasteurization of machining 

coolants 

Chemical reduction of hexavalent chromium 

Cyanide destruction 

Chemical reduction of chelated metals 

Chemical emulsion breaking and gravity oil/water separation 

Chemical emulsion breaking and dissolved air flotation 

Gravity oil emulsion breaking (baseline only, see 

Section 11.3.4) 

Ultrafiltration for oil removal 

Contract hauling of solvent degreasing wastewaters 

Chemical precipitation 

Inclined clarification for solids removal 

Microfiltration for solids removal 

Sludge thickening 

Sludge pressure filtration 

Multimedia filter (baseline only, see Section 11.3.4) 

Source: MP&M Surveys, MP&M Site Visits, Technical Literature. 

11.3.3.1 Modeling Technology Options 

The model drivers access technology modules in the proper order for each 

technology option (e.g., in-process flow control and pollution prevention followed by end-of-pipe 

treatment). The drivers’ logic dictates which unit operations feed which treatment technologies. 

EPA assumed wastewater destination based on unit operation wastewater characteristics: 

cyanide-bearing wastewater feeds cyanide destruction and flowing rinses feed countercurrent 

cascade rinsing. Table 11-12 lists the assigned unit operations feeding each treatment 

technology. Note that a unit operation can feed more than one treatment technology or inprocess pollution prevention technology. EPA assumed that the model sites commingled all 

MP&M wastewater generated for treatment by chemical precipitation, inclined clarification or 

microfiltration for solids removal, sludge thickening, and sludge pressure filtration, except for 

wastewater from the Oily Wastes, Shipbuilding Dry Dock, and Railroad Line Maintenance 

Subcategories, and except for solvent-bearing wastewater, for which EPA estimated costs for offsite disposal. 

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11.0 - Costs of Technology Bases for Regulations 

Table 11-12	

List of Unit Operations Feeding Each Treatment Unit 

or In-Process Technology 

Treatment Technology/Pollution 

Prevention Technology Unit Operations Feeding Technologya 

Countercurrent cascade rinsing Acid treatment with chromium rinse 

Acid treatment without chromium rinse 

Alkaline cleaning for oil removal rinse 

Alkaline treatment with cyanide rinse 

Alkaline treatment without cyanide rinse 

Anodizing with chromium rinse 

Anodizing without chromium rinse 

Aqueous degreasing rinse 

Barrel finishing rinse 

Chemical conversion coating without chromium rinse 

Chemical milling rinse 

Chromate conversion coating rinse 

Corrosion preventive coating rinse 

Electrochemical machining rinse 

Electroless plating rinse 

Electrolytic cleaning rinse 

Electroplating with chromium rinse 

Electroplating with cyanide rinse 

Electroplating without chromium or cyanide rinse 

Electropolishing rinse 

Heat treating rinse 

Salt bath descaling rinse 

Solvent degreasing rinse 

Stripping (paint) rinse 

Stripping (metallic coating) rinse 

Testing rinse 

Washing finished products rinse 

Carbon black deposition rinse 

11-27

11.0 - Costs of Technology Bases for Regulations 

Table 11-12 (Continued) 

Treatment Technology/Pollution 

Prevention Technology Unit Operations Feeding Technologya 

Countercurrent cascade rinsing (cont.) Galvanizing/hot dip coating rinse 

Mechanical plating rinse 

Laundering rinse 

Cyanide rinsing 

Ultrasonic machining rinse 

Phosphor deposition rinse 

Centrifiguration and pasteurization of 

machining coolant 

Multiple unit operation rinse 

Grinding 

Machining 

Centrifugation of painting water curtains Painting - spray or brush 

Painting - immersion 

Chemical emulsion breaking and oil/water 

separation 

OR 

Dissolved air flotation 

OR 

Ultrafiltration system for oil removal 

Alkaline cleaning for oil removal and rinse 

Alkaline treatment without cyanide 

Aqueous degreasing 

Assembly/disassembly 

Electrical discharge machining rinse 

Electrolytic cleaning 

Electroplating without chromium or cyanide 

Floor cleaning and rinse 

Grinding 

Grinding rinse 

Heat treating 

Impact deformation and rinse 

Machining and rinse 

Painting - spray or brush 

Painting - immersion 

Pressure deformation 

Steam cleaning rinse 

Stripping (paint) 

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11.0 - Costs of Technology Bases for Regulations 

Table 11-12 (Continued) 

Treatment Technology/Pollution 

Prevention Technology Unit Operations Feeding Technologya 

Chemical emulsion breaking and oil/water 

separation 

OR 

Dissolved air flotation 

OR 

Ultrafiltration system for oil removal 

Stripping (metallic coating) rinse 

Testing 

Thermal cutting rinse 

Washing finished products and rinse 

Bilge water 

Mechanical plating 

Photo image developing 

Photo imaging 

Steam cleaning 

Vacuum impregnation 

Laundering 

Calibration 

Centrifugation and pasteurization of machining coolant 

Chemical reduction of hexavalent chromium Acid treatment with chromium and rinse 

Anodizing with chromium and rinse 

Chromate conversion coating and rinse 

Electroplating with chromium and rinse 

Stripping (paint) 

Wet air pollution control - chromium 

Chromium drag-out reduction and rinse 

Chemical reduction of chelated metals Electroless plating and rinse 

Cyanide destruction Alkaline treatment with cyanide and rinse 

Electroplating with cyanide and rinse 

Cyanide rinsing and rinse 

Cyanide drag-out destruction and rinse 

Wet air pollution control - cyanide 

Solvent hauling Solvent degreasing 

a

A unit operation can feed more than one treatment technology or in-process pollution prevention technology. EPA 

assumed that the model sites commingled all MP&M wastewater generated for treatment by chemical precipitation, 

inclined clarification or microfiltration for solids removal, sludge thickening, and sludge pressure filtration, except 

for wastewater from the Oily Wastes, Shipbuilding Dry Dock, and Railroad Line Maintenance Subcategories, and 

except for solvent-bearing wastewater, for which EPA estimated costs for off-site disposal. 

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11.0 - Costs of Technology Bases for Regulations 

11.3.3.2 Modeling Flow Reduction 

Figure 11-2 shows the logic used by the cost model to apply the in-process flow 

reduction to each model site. EPA estimated flow reductions resulting from applying in-process 

pollution prevention technologies to any streams that did not already have the technology in 

place (see Section 11.2.4). The estimated flow reductions are as follows: 

� EPA estimated a 20- to 80-percent flow reduction achieved by converting 

the current rinse scheme in place to countercurrent cascade rinsing (DCN 

15993, Section 6.7.1 of the rulemaking record and Section 15.0 of this 

document and 1996 survey data). The flow reduction applied depends on 

the rinse scheme currently in place. An 80-percent flow reduction 

corresponds to converting a high-flow two-stage continuous overflow 

rinse to a two-stage countercurrent cascade rinse. A 20-percent flow 

reduction corresponds to converting a stagnant rinse followed by a 

continuous overflow rinse to a two-stage countercurrent cascade rinse. 

EPA computed the flow reductions based on information collected in the 

MP&M surveys. 

� EPA assumed that centrifugation and pasteurization of machining coolants 

reduced coolant use by 80 percent (see Section 6.7.1 of the rulemaking 

record, DCN 15802). EPA assumed that a site combined all wastewater 

from machining operations prior to centrifugation and pasteurization of 

machining coolants. 

� EPA assumed that centrifugation of painting water curtains allowed 100 

percent reuse of the treated wastewater in the painting booth, or zero 

discharge (sludge removed from the centrifuge is contract hauled). EPA 

assumed a site combined wastewater from painting streams prior to paint 

curtain centrifugation. 

11.3.3.3 Modeling End-of-Pipe Treatment for Metal Bearing Subcategories 

The logic used by the model drivers to access end-of-pipe technologies varies 

depending on whether the subcategory is primarily metal bearing or oil bearing. Figure 11-3 

presents the logic used by the cost model to apply the end-of-pipe treatment technologies and 

practices for the following metal-bearing wastewater subcategories: General Metals, Metal 

Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Board, and Steel Forming and 

Finishing. In developing costs, EPA assumed sites would segregate wastewater streams 

according to pollutant characteristics (chromium, cyanide, chelated metals, oil, and solvent). 

Segregating wastewater streams provides the most efficient and effective treatment of wastes. 

Because treating solvent-bearing waste streams may require Treatment Storage and Disposal 

(TS&D) permitting, EPA assumed model sites would contract for off-site disposal of solventbearing wastewater streams, while the other segregated wastewater streams would receive 

11-30

11.0 - Costs of Technology Bases for Regulations 

preliminary treatment. The cost model assumed that effluent from preliminary treatment 

technologies would be combined with other wastewater streams that did not require preliminary 

treatment prior to estimating the cost of treating the combined wastewater. Model drivers also 

direct treatment unit order; for example, sludge from chemical precipitation goes to thickening 

and pressure filtration prior to off-site disposal. EPA assumed wastewater from chemical 

precipitation and sedimentation systems would be discharged to either a surface water or POTW 

according to the model site’s current discharge destination (see Section 11.3.4 for general 

discharge status assumptions for sites with multiple discharge destinations). 

11.3.3.4 Modeling End-of-Pipe Treatment for Oily Subcategories 

The model drivers access modules to simulate oily wastewater treatment. Figure 

11-4 presents the logic used to apply the end-of-pipe treatment technologies and pollution 

prevention practices for the Oily Wastes, Railroad Line Maintenance, and Shipbuilding Dry 

Dock Subcategories. Each of these subcategories generates wastewater that primarily contains 

oily constituents and low concentrations of dissolved metals; therefore, EPA did not include 

chemical precipitation and sedimentation following oil treatment for these subcategories. 

11.3.3.5 Model Output 

The model drivers track output including the following site-specific information 

for each technology: 

� Total direct capital costs;


� Total direct annual costs;


� Electricity used and associated cost;


� Sludge generation and associated disposal costs;


� Waste oil generation and associated disposal costs;


� Water-use reduction and associated cost credit;


� Chemical usage reduction and associated cost credit;


� Effluent flow rate; and


� Effluent pollutant concentrations. 


Section 11.6 discusses calculation specifics for each technology module. 

11.3.4 General Assumptions Made During the Costing Effort 

This subsection presents general assumptions that EPA included in the cost 

model. Section 11.4 discusses specific assumptions made for NODA and post-NODA analyses. 

Section 11.6 discusses technology-specific assumptions. 

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11.0 - Costs of Technology Bases for Regulations 

Baseline Year Determination 

EPA estimated costs for the MP&M industry for the base years 1989 and 1996 

(the years in which survey data were collected). The Agency included sites (or operations) that 

operated during the 1989 and 1996 calendar years in the cost and loadings analyses if the site 

operated at least one day during the respective calendar year. If a site (or operation) shut down 

before 1996, it was removed from the costing and pollutant loadings analyses. If a site (or 

operation) commenced after 1989 (Phase I) or 1996 (Phase II), EPA did not include the site (or 

operation) in the costing or pollutant loadings analyses. See Section 3.1 for additional 

information regarding EPA’s use of 1996 as the base year for its analyses for this rule. 

Furthermore, if a site did not discharge wastewater to surface water or a POTW in 1989 (Phase I) 

or 1996 (Phase II) (e.g., was a zero or alternative discharger), then EPA excluded the site from 

the costing and pollutant loadings analysis. 

If EPA has information that a Phase I site installed or significantly altered its 

wastewater treatment systems before 1996, EPA used the updated data. Also, if a site changed 

its discharge status before 1996, EPA used the updated discharge status in its analyses. Some 

sites provided information during the comment period that corrected information submitted with 

their survey. For example, a Phase 1 site may have completed its survey as having no treatment 

for oily discharges but submitted information during comment that it had installed treatment 

prior to 1996. In these cases, EPA revised the input data to reflect the corrected site information. 

Capacity of End-of-Pipe Technology in Place 

For sites with technology in place, EPA assessed the design capacity flow for each 

treatment unit using the derived design capacity flow from the larger of two values: the site’s 

reported survey design capacity flow or the flow calculated by the cost model baseline run, as 

described in Section 11.2.4, assuming the baseline flow is 78 percent of the design capacity flow. 

MP&M survey data indicate, on average, that flow entering the treatment units is 78 percent of 

the design flow reported by the survey respondent. Therefore, rather than assuming that the site 

is operating at 100 percent of the design capacity when survey information is unavailable, EPA 

assumed the site is operating at 78 percent of the design capacity. Therefore, flows can increase 

by as much as 22 percent over the current flow before either additional treatment capacity or 

contract hauling is required (see Section 6.7 of the rulemaking record, DCN 15902). The Agency 

determined the need for greater capacity using the following logic: 

� If the technology was not in place at the model site, then EPA assigned 

capital costs to the site for a treatment unit of sufficient capacity. 

� If the technology was in place at the model site with sufficient capacity to 

treat all of the applicable MP&M wastewater, then EPA assigned no 

additional capital costs. 

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11.0 - Costs of Technology Bases for Regulations 

� If the site had a technology in place equivalent to the option technology 

but with insufficient capacity to treat all the applicable MP&M 

wastewater, then EPA assumed the site would operate the existing system 

at full capacity. EPA assigned costs for the option technology train to run 

in parallel with the existing treatment to handle the additional flow. 

Contracting for Off-Site Treatment/Disposal in Lieu of Treatment 

EPA assessed the cost to contract for off-site treatment/disposal of wastewater 

compared to on-site treatment. Because many MP&M sites have flow rates less than the 

minimum design capacity for treatment, EPA determined that some model sites would contract 

for off-site disposal of wastewater rather than treat it on site. If off-site disposal was less 

expensive than treatment on site, EPA assumed the site would dispose of the wastewater off site. 

EPA compared off-site disposal versus on-site treatment for individual technologies and their 

influent flow rates, rather than on the total site wastewater treatment system. For example, a site 

may find it less expensive to contract for off-site disposal of cyanide-bearing wastewater than to 

install and operate a cyanide destruction treatment system. However, it would still be less 

expensive to treat all other wastewater streams on site. To determine whether treatment on site 

was less expensive then contracting for off-site disposal, EPA compared total annualized costs 

assuming an equipment life expectancy of 15 years and an annual interest rate of 7 percent. 

EPA used MP&M survey data to determine the unit cost ($/gal or $/lb) 

to contract for off-site treatment/disposal for various waste types (see Section 6.7.1 of the 

rulemaking record, DCN 16023). EPA compared the costs of the following technologies to 

contracting for off-site disposal in lieu of treatment costs: 

� Centrifugation and pasteurization of machining coolants; 

� Centrifugation of painting water curtains (general metal-bearing waste and 

paint sludge); 

� Chemical reduction of hexavalent chromium; 

� Cyanide destruction; 

� Chemical reduction of chelated metals; 

� Chemical emulsion breaking and gravity oil/water separation; 

� Dissolved air flotation; 

� Ultrafiltration for oil removal; 

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11.0 - Costs of Technology Bases for Regulations 

� Chemical precipitation and sedimentation; and 

� Sludge pressure filtration. 

In the case of wastewater requiring chemical precipitation and sedimentation 

treatment, EPA compared the costs of contracting for off-site disposal of the untreated end-ofpipe wastewater to the cost of the entire treatment system, which includes chemical precipitation, 

sedimentation (gravity clarification or microfiltration), sludge thickening, and pressure filtration. 

Equipment Size Ranges 

EPA developed equipment cost equations for each component of the treatment 

technologies. The equations are valid between the minimum and maximum sizes (e.g., flow 

rates, volume capacities) from which EPA developed the equations. For wastewater capacities 

below the minimum range of validity, the cost model designed the equipment at the minimum 

size. For wastewater capacities above the maximum range of validity, the cost model designed 

multiple units of equal capacity to operate in parallel. 

Batch Schedules 

EPA designed either batch or continuous systems, depending on each model site’s 

operating schedule and discharge flow rate. The Agency also designed wastewater treatment 

operations such that the minimum system would be operated at capacity. For example, if the 

minimum cyanide destruction system was 480 gallons per batch, and a site generated 80 gallons 

of cyanide-bearing wastewater per day, then the cost model designed the cyanide destruction 

system to treat a 480-gallon batch once every six days. 

Dilute Influent Concentrations 

In rare cases, high wastewater flow rates at some sites resulted in pollutant 

concentrations below the long-term average technology effectiveness concentrations (discussed 

in Section 10.0) even after flow reduction from in-process pollution prevention practices. In 

these cases, EPA assumed the site did not require treatment to meet the EPA option for that 

wastewater stream and therefore did not include end-of-pipe costs. 

11.4
 Specific Methodology and Assumptions Used to Estimate Costs for 

Treatment Technologies 

EPA made many changes in cost model assumptions and methodology made 

based on comments submitted during both the proposed rule and the NODA comment periods. 

This subsection describes the changes to proposal methodology and assumptions that EPA used 

to estimate both the costs presented in the NODA and those developed for the final rule. The 

methodology and assumptions used for the costs presented in the Development Document for the 

Proposed Effluent Limitations Guidelines and Standards for the Metal Products & Machinery 

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11.0 - Costs of Technology Bases for Regulations 

Point Source Category (EPA 821-B-00-005) are discussed in that document. EPA updated 

information regarding unit operations, discharge status, operating schedule, and flow throughout 

the costing effort, based on industry comments and corrections to submitted survey data. 

11.4.1 NODA Cost Estimates 

For the costs presented in the NODA, EPA revised the following inputs and logic 

of the proposed cost model: 

� Pollutant concentration;


� Subcategorization scheme;


� Discharge status;


� Wastewater treatment determination;


� Wastewater flow;


� Treatment modules;


� Statistical weighting factors; and


� Post processing.


EPA also added an option: upgrading treatment from 40 CFR 413 standards to 

those of 40 CFR 433. The remainder of this subsection describes all these changes in detail. 

Pollutant Concentrations 

EPA revised the calculation of pollutant concentrations from unit operations. 

First, the Agency incorporated additional data submitted with comments and from the Phase III 

sampling (see Section 3.0 for details on data sources). Next, EPA reclassified sampling data unit 

operations, including revising one sample point to be a drag-out rinse and adding more printed 

wiring board unit operations (see Section 12.0 for details). See Section 24.7 of the rulemaking 

record, DCN 17890, for details of these changes. 

Subcategorization Scheme 

In response to industry comments, EPA made the following adjustments to the 

subcategorization scheme for analyses presented in the NODA: 

� Printed Wiring Board Assembly facilities in the Metal Finishing Job 

Shops Subcategory were moved to the General Metals Subcategory. 

Facilities that perform only Printed Wiring Board Assembly operations 

remained in the General Metals Subcategory. 

� Printed Wiring Board Job Shops were moved from the Metal Finishing 

Job Shops Subcategory into the Printed Wiring Board Subcategory. 

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11.0 - Costs of Technology Bases for Regulations 

� Additional unit operations were included in the Oily Wastes Subcategory 

based on new sampling data and data submitted with comments. 

� Zinc platers were defined and segregated from the General Metals and 

Metal Finishing Job Shops Subcategories for some analyses for EPA’s 

consideration of a zinc platers subcategory or segment. 

Discharge Status 

For NODA analyses, EPA revised the discharge status determination for sites 

submitting MP&M Phase I surveys to better reflect the MP&M Phase II discharge status 

hierarchy. The discharge status for all sites was thus based on the following assumptions: 

� EPA considered a site with a direct discharging stream as direct, regardless 

of any indirect or zero-discharging streams (i.e., all streams at the site were 

considered to be direct); 

� EPA considered a site with an indirect discharging stream and no direct 

streams as indirect, regardless of any zero-discharging streams; and 

� EPA considered a site with no direct or indirect streams a contract-haul, 

reuse, or zero-discharge site. 

Wastewater Treatment Determination 

EPA updated the treatment in place based on the following additional comment 

data and new assumptions: 

� In response to industry comments, EPA considered end-of-pipe ion 

exchange equivalent to cyanide destruction for sites discharging cyanidebearing wastewater. See Section 20.3 of the rulemaking record, DCN 

17947, for the industry comment information. 

� For sites responding to the Short and Municipality Surveys, EPA no longer 

considered neutralization/pH adjustment equivalent to chemical 

precipitation. EPA considered only neutralization/pH adjustment with 

clarification or sludge removal equivalent to chemical precipitation. 

� EPA assumed that sites with baseline pollutant concentrations less than the 

option technology pollutant concentrations did not require any additional 

treatment. 

� EPA verified cost model input database accuracy versus the site surveys 

and resolved inconsistencies, such as stream discharge destination. 

11-36

11.0 - Costs of Technology Bases for Regulations 

Wastewater Flow 

EPA revised flow imputations for sites not reporting unit operation discharges. 

The sum of imputed flows was verified to be less than the total reported facility flow, where 

available. Additionally, EPA excluded recirculated flow from the imputation to reduce the 

potential for overinflated imputations. See Section 16.6.1 of the rulemaking record, DCN 27711. 

Statistical Weighting Factors 

EPA incorporated new statistical weighting factors. The Agency adjusted some 

Phase I survey weights to account for additional zero dischargers and to exclude ineligible 

facilities. See Section 19.5 of the rulemaking record, DCN 36086. 

Post Processing 

EPA adjusted model logic, allowing treatment costs to be estimated on individual 

wastestreams for the Railroad Line Maintenance and Steel Forming and Finishing Subcategories. 

EPA also allowed for cost savings from the addition of pollution prevention technologies. 

40 CFR 413 to 433 Upgrade Analysis 

To consider the industry comment that the proposed standards were too stringent, 

EPA examined a new option: to upgrade from the 40 CFR 413 standards to 40 CFR 433 

standards. EPA approximated compliance costs and load reductions associated with upgrading 

facilities from the Electroplating (40 CFR 413) rule to the Metal Finishing (40 CFR 433) rule. 

The 40 CFR 413 rule, promulgated in 1981, is based on older technology than the 40 CFR 433 

rule, promulgated in 1983. Section 9.0 presents the option technology associated with the Part 

413 to 433 Upgrade Analysis. Section 11.5 discusses how EPA estimated costs for each 

component of the option technology, and Section 12.0 discusses how EPA estimated the 

pollutant loadings reductions associated with the Upgrade Analysis. 

11.4.2 Post-NODA Cost Estimates 

Following receipt of industry comment on the analyses presented in the NODA, 

EPA revised parts of the costing approach. The remainder of this subsection describes the 

changes made between the NODA and promulgation: how EPA incorporated new data received 

and revised assumptions and parts of the costing methodology. 

Treatment Modules Updates 

EPA revised and updated treatment modules. Most notably, EPA added 

monitoring costs for tin, sulfide, and lead for all sites. EPA revised the off-site disposal 

methodology to haul nickel-bearing wastewater prior to chemical precipitation if the model 

determines not to treat via chemical precipitation and sedimentation. EPA also added costs for 

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11.0 - Costs of Technology Bases for Regulations 

sand (multimedia) filters as a technology option. For more details on these and other revisions, 

refer to Section 16.6.1, DCN 16741, and Section 24.6.1, DCN 17935, of the rulemaking record. 

Discharge Status 

Post-NODA, EPA altered its discharge status determination to allow a site to have 

multiple discharge statuses (e.g., direct discharge, indirect discharge, and zero discharge). The 

approach was changed to more accurately reflect the actual site situation. At the time of the 

proposed rule and the NODA, EPA classified discharge status for an entire site, instead of each 

wastestream. For analyses after the NODA, EPA assigned a discharge status to each wastewater 

treatment system. 

Flow Estimates 

EPA revised the flow imputation methodology used to estimate flows for sites that 

did not provide them. The new methodology allowed for zero discharge as a possible imputation 

result. See Section 28.2 of the rulemaking record, DCN 36200 for more detail on imputed flows. 

Treatment in Place 

In response to industry comments to ensure proper consideration of the baseline 

treatment in place, EPA reconsidered additional treatment technologies equivalent to the option 

technologies: 

� EPA now considers end-of-pipe and in-process ion exchange equivalent to 

cyanide destruction for cyanide-bearing wastestreams without any other 

cyanide treatment; 

� EPA now considers end-of-pipe and in-process ion exchange equivalent to 

chemical precipitation plus a filter press for metals-bearing wastestreams 

without other metals treatment; 

� Dissolved air flotation is considered equivalent to chemical precipitation 

treatment for metals-bearing wastestreams without other metals treatment 

for the 413 to 433 Upgrade option; 

� Any type of oily wastewater treatment (e.g., belt skimming) is equivalent 

to chemical emulsion breaking and oil/water separation; and 

� The presence of a holding tank and sludge removal after some chemical 

addition is now considered equivalent to chemical precipitation followed 

by clarification. 

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11.0 - Costs of Technology Bases for Regulations 

11.5 Costing Methodologies for Direct Discharging Oil-Bearing Subcategories 

Commentors supplied additional DMR and sampling data during the postproposal and post-NODA comment periods. Due to the small number of model facilities in each 

of the oil-bearing subcategories and the high percentage of supplied DMR sampling data, EPA 

was able to use site-specific effluent discharge information as a major part of the costing process. 

(One hundred percent of the direct discharging railroad line maintenance facilities supplied 

sampling data and some associated sampling frequency information. Ninety-two percent of the 

direct discharging oily wastes facilities, with treatment in place, supplied sampling data and some 

associated sampling frequency information. Fifty percent of the shipbuilding dry dock facilities 

supplied sampling data and some associated sampling frequency information.) The methodology 

used in each of the oil-bearing subcategories is discussed below. 

11.5.1 Oily Wastes Costing Methodology 

For the Oily Wastes Subcategory, EPA calculated the costs for the final rule 

through the following methodology. If a model site had provided DMR data, it was reviewed to 

determine baseline compliance with the final MP&M LTAs. If the data indicated the model site 

was currently meeting the LTAs, no additional costs were applied to the site. If the DMR data 

indicated the model site was not currently meeting the LTAs, and the survey indicated that the 

facility had Option 6 technology (or equivalent) in place, then the cost model output was 

reviewed. If the model determined that pollution prevention (P2) could be added to the site, then 

only P2 costs were assigned. It was assumed that adding P2 would lower the flow into the 

treatment system and help increase the system removals. If the site already had P2 in place, then 

a one-time upgrade cost was added. This upgrade cost was intended to help the facility better 

operate their treatment system through use of a consultant, subsequent operator training, and 

some additional treatment control equipment. The upgrade was considered a capital cost and 

totaled $10,700 ($2001). This is made up of the costs listed below (for more details on how each 

of these costs were derived, see DCN 17906 located in Section 24.6.1 of the rulemaking record): 

� $5,500 for consultant fees; 

� $2,200 for operation training; and 

� $3,000 for a new pH meter. 

If the DMR data indicated the model site was not currently meeting the LTAs, and the survey 

indicated that the facility did not have Option 6 technology (or equivalent) in place, then the cost 

model output was used. 

If the model site did not have DMR data, it was reviewed to determine the level of 

treatment in place. If the survey indicated the facility did have Option 6 technology (or 

equivalent) in place, then EPA set the baseline discharge concentrations to the median of the 

DMR data. Because the calculated medians for oil and grease and TSS were below the final 

MP&M LTA’s, no additional costs were added. (Note that, if they had been above the final 

MP&M LTA’s, then EPA would have added a one-time upgrade cost.) If the survey indicated 

11-39

11.0 - Costs of Technology Bases for Regulations 

the facility did not have Option 6 technology (or equivalent) in place, then the cost model output 

was used. 

11.5.2 Railroad Line Maintenance Costing Methodology 

For the Railroad Line Maintenance (RRLM) Subcategory, the AAR survey 

information discussed in Section 3.0 was used. Each survey contained information on effluent 

concentrations, flow, and treatment currently in place. The AAR surveys indicated that all direct 

discharging facilities in the RRLM Subcategory currently use wastewater treatment equivalent to 

or better than Option 6. Additionally, most of the facilities have NPDES daily maximum permit 

limitations for oil and grease (as HEM) and TSS as 15 and 45 mg/L, respectively. Based on this 

information, EPA concluded that these oil and grease (as HEM) and TSS daily maximum limits 

represent the average of the best performances of facilities utilizing Option 6 technology. 

EPA evaluated the compliance costs associated with establishing BPT daily 

maximum limitations equivalent to 15 and 45 mg/L for oil and grease (as HEM) and TSS, 

respectively, and concluded all facilities currently meet a daily maximum oil and grease limit of 

15 mg/L and most currently monitor once per month. With one exception, all facilities are 

currently meeting a TSS daily maximum limit of 45 mg/L. If EPA had decided to develop Part 

438 limitations for this subcategory, it would have estimated incremental costs associated with 

bringing this one facility into compliance with the TSS limit. 

11.5.3 Shipbuilding Dry Dock Costing Methodology 

No additional costs were estimated for this subcategory. Following proposal, 

EPA received comments and supporting data indicating that its estimates of current pollutant 

discharges from this subcategory were overestimated. In particular, commentors claimed that 

current discharges of oil and grease were minimal and that national regulation was not warranted 

for this subcategory. EPA incorporated the additional information provided by commentors into 

its analysis and now concludes that direct discharges from these facilities generally contain 

minimal levels of all pollutants. In particular, current oil and grease discharges from these 

facilities are not detectable (< 5 mg/L) or nearly not detectable. EPA has similarly determined 

that TSS discharges are, on average, minimal. The data show that TSS discharges may increase 

episodically, particularly when the dry dock is performing abrasive blasting operations. However, 

EPA has concluded that these episodic discharges from six facilities do not warrant national 

regulation. If EPA had decided to develop Part 438 limitations for this subcategory, it would 

have estimated incremental costs associated with lowering and/or controlling the episodic TSS 

discharges. 

11.6 Design and Costs of Individual Pollution Control Technologies 

This subsection discusses in detail the design and costing of the individual 

technologies that compose the technology options. Table 11-13 presents the capital and annual 

cost equations for the specific equipment mentioned in each technology description below. When 

11-40

11.0 - Costs of Technology Bases for Regulations 

tanks were a component of an option, EPA estimated that each wastestream would need only one 

tank, unless the technology required a reserve tank, such as chemical emulsion breaking. EPA 

estimated the tank volume needed based on Equation 11-2 in Section 11.2.4. The remainder of 

this subsection describes the tank requirements of each individual technology. Additional 

documentation is available in Section 24.6.1 of the rulemaking record, DCN 17885. 

11.6.1 Countercurrent Cascade Rinsing 

The Agency estimated costs for countercurrent cascade rinses for flowing rinses at 

the model sites. The countercurrent cascade rinse module estimates a cost and flow reduction 

associated with the conversion to a two-stage countercurrent rinse. Section 15.2.4 gives more 

information on countercurrent cascade rinsing flow reduction as related to the site’s existing rinse 

scheme. 

EPA estimated capital and annual costs based on the model site’s current rinse 

schemes. The module included capital and annual costs for the following equipment when 

necessary. 

� A second rinse tank with a volume equal to the volume of the existing 

tank; 

� Transfer pumps and piping; and 

� An air-agitation system. 

EPA assumed there would not be additional O&M costs for replacing the current 

rinse scheme with a two-stage countercurrent cascade rinse. Direct annual costs for this module 

included increased energy costs but a reduced water cost due to water-use reduction. EPA 

calculated the water savings obtained from converting the rinse to countercurrent cascade and 

used a water cost of $2.03 per 1,000 gallons to subtract the cost savings from the site’s total 

annual cost. 

11.6.2 Centrifugation and Pasteurization of Machining Coolant 

EPA estimated costs for centrifugation and pasteurization of machining coolant 

for machining and grinding operations discharging water-soluble or emulsified coolant (listed in 

Table 11-13). EPA estimated the costs of a liquid-liquid separation centrifuge to remove solids 

and tramp oils and a pasteurization unit to reduce microbial growth. The costed systems 

included the following equipment in Table 11-13: 

� High-speed, liquid-liquid separation centrifuge; 

� Pasteurization unit; and 

� Holding tanks for large-volume applications. 

11-41

11.0 - Costs of Technology Bases for Regulations 

EPA provided a 50-percent excess capacity to account for fluctuations in 

production resulting from flow rates greater than 14 gallons per minute. The Agency developed 

capital and annual cost estimates from vendor data on packaged systems of different capacities. 

Direct annual costs included O&M labor and materials, energy costs, sludge and waste oil 

disposal costs, and a cost credit for water- and coolant-use reduction. EPA estimated 

maintenance labor at one hour per week and operating labor at one hour per shift. 

Based on site visit and vendor information, EPA assumed that this technology can 

reduce coolant discharge by 80 percent. The Agency based the amount of coolant and water 

saved on the model site recycling 80 percent of the coolant and discharging a 20-percent 

blowdown stream to oil treatment. From site visit and vendor information, EPA estimated the 

coolant solution to be 95 percent water and 5 percent coolant. 

11.6.3 Centrifugation of Painting Water Curtains 

EPA estimated costs for centrifugation of painting water curtains (listed in Table 

11-13), which included a centrifuge and a holding tank large enough to hold flow for one hour. 

Direct annual costs included O&M labor and materials, energy costs, sludge disposal costs, and a 

cost credit for water-use reduction. EPA estimated maintenance labor at one hour per week and 

operating labor at one hour per shift. 

EPA assumed that a model site reused all water discharged from the 

centrifugation system in painting operations, and contracted for off-site disposal of the sludge 

from the system. EPA estimated off-site disposal costs using the average paint sludge hauling 

costs reported in the 1996 MP&M Detailed Survey. Because actual disposal costs depend more 

on site-specific conditions (e.g., paint type and spray-gun cleaner requirements) than RCRA 

hazard classification, EPA estimated costs by averaging the costs for RCRA hazardous and 

nonhazardous paint sludges together. (See Table 11-14 for off-site disposal costs and Section 

11.6.4 for more detailed information.) 

11-42

11.0 - Costs of Techno

11-43

Table 11-13

MP&M Equipment Cost Equationsa

Equipment Equation 

Countercurrent cascaderinsing

A = [(0.0004 x TANKVOL + 0.2243)] x DPY x HPD x 0.047

- [(Y-CCFLOW) x 60 x HPD x DPY x 0.00203]

C = 6.047 x TANKVOL + 3,784.3; Tank, piping, and pumpC = 0.5077 x TANKVOL + 1077.8; Piping and pumpC = 8 x 29.67; Labor only

Machine coolantregeneration system(including holding tanks)

A = [18 x 0.047 x DPY x HPD x NUM] + [(HPD/8) x DPY x 29.67 x NUM] + [(DPY/5) x 29

x NUM] + [0.002 x Y x 60 x HPD x DPY x 1.95]+ [0.05 x Y x 60 x HPD x DPY x 0.86] [0.05 x 0.80 x Y x 60 x HPD x DPY x 9.03] - [0.95 x 0.8 x Yx 60 x HPD x DPY x 0.0020

C = 41,422 C = 110,205 C = 142,831 C = 164,009 C = 191,331 

Paint curtain centrifuge A = [0.047 x KW x HPD x DPY] + [(HPD/8) x DPY x 29.67] + [(DPY/5) x 29.67]

+ [TSS x 3.785/106 x 2.2/0.4 x Y x 60 x HPD x DPY/8.5 x 3.7]- [(Y x 60 x HPD x DPY) - (TSS x 3.785/106 x 2.2/0.4 x Y x 60 x HPD x DPY/8.35)] x0.00203

C = 7,254 (kW = 0.4) C = 10,325 (kW = 1.5) C = 47,104 (kW = 2.2) C = 62,936 (kW = 3.7) 
11-44

Table 11-13 (Continued)

11.0 - Costs of Techno

Equipment Equation 

Feed system, aluminumsulfate (alum)

A = 0.35 x 0.7456 x HPD x DPY x 0.047 C = 6,622 C = 142.88 x Y + 6,412 A = [1.36 x HPD x DPY x 0.047] + [0.0006615 x Y x 60 x HPD x DPY] + [(HPD/8) x DPY x

29.67] + [(DPY/5) x 29.67]

A = [1.49 x HPD x DPY x 0.047] + [0.0006615 x Y x 60 x HPD x DPY] + [(HPD/8) x DPY x

29.67] + [(DPY/5) x 29.67]

C = 9.7882 x Y + 9,718.7 

Feed system, calciumchloride, continuous

A = [[(0.0061 x Y) + 1.1696] x HPD x DPY x 0.047] + [0.00125 x Y x 60 x HPD x DPY] C = 10,299 C = 28.805 x Y + 10,683 

Feed system, calciumhydroxide (lime),continuous

A = 0.25 x 0.7456 x HPD x DPY x 0.047 C = 8,489 C = 47.713 x Y + 8,445 A = [[(0.0006 x Y) + 1.2961] x HPD x DPY x 0.047] + [0.000117 x Y x 60 x HPD x DPY] C = 24.586 x Y + 12,830

Feed system, ferricsulfate, continuous

A = 0.35 x 0.7456 x HPD x DPY x 0.047 C = 5,200 C = 52.991 x Y + 5,118 A = [[(0.0009 x Y)+ 1.3313] x HPD x DPY x 0.047] + [0.0000434 x Y x 60 x HPD x DPY] C = 11.56 x Y + 9,762.9
11-45

Table 11-13 (Continued)

11.0 - Costs of Techno

Equipment Equation 

Feed system, polymer A = [0.2833 x HPD x DPY x 0.047] + [0.001 x Y x 60 x HPD x DPY] 

C = 3,686A = [[(0.0034 x Y) + 1.4171] x HPD x DPY x 0.047] + [0.001 x Y x 60 x HPD x DPY] C = 20.685 x Y + 9,822

Feed system, sodiumhydroxide, continuous(caustic)

A = [0.1864 x HPD x DPY x 0.047] + [0.0042 x Y x 60 x HPD x DPY] C = 4,503A = [[(0.0071 x Y) + 1.1584] x HPD x DPY x 0.047] + [0.0042 x Y x 60 x HPD x DPY] C = 77.564 x Y + 21,506

Feed system, sulfuricacid

A = [0.0373 x HPD x DPY x 0.047] + [0.000222 x Y x 60 x HPD x DPY] C = 4,110A = [[(0.0023 x Y) + 1.683] x HPD x DPY x 0.047] + [0.000222 x Y x 60 x HPD x DPY] C = 56.416 x Y + 17,769

Chemical emulsionbreaking, coalescent plate separator (gravityoil/water separator)[requires sulfuric acid,alum, caustic, andpolymer feed systems]

A = [(0.0019 x Y + 2.009) x 0.7456 x HPD x DPY x 0.047] x NUM + [29.67 x (HPD/8) x DP

+ [(DPY/5) x 29.67] x NUM + [3.664 x Y x HPD x DPY]

C = 42,261 C = 3,916.2 x Y + 30,278 + 2,452 x Y +1,132 A = [(0.096 x Y + 2.039) x 0.7456 x HPD x DPY x 0.047] x NUM + [29.67 x (HPD/8) x DPY

+ [(DPY/5) x 29.67] x NUM + [3.664 x Y x HPD x DPY]

C = 86,720 C = 845.43 x Y + 65,284 + 2,452 x Y + 1,132 

Dissolved air flotation[requires lime, ferricsulfate, and polymerfeed systems]

See ultrafiltration for oil removal. A = [(0.0728 x Y + 3.072) x HPD x DPY x 0.047] + [0.0045 x Y x 60 x HPD x DPY] + [29.6

HPD x DPY] + [(DPY/5) x 29.67] + [0.86 x 0.0003 x Y x 60 x HPD x DPY] + [0.86 x 0.0x Y x 60 x HPD x DPY]

C = 1,125.4 x Y + 137,936
11-46

Table 11-13 (Continued)

11.0 - Costs of Techno

Equipment Equation 

Ultrafiltration for oilremoval

A = [(0.71 x Y + 5.46) x HPD x DPY x 0.047] + [0.4 x Y + 0.3] + [0.5 x HPD x DPY x29.67] 

[(DPY/5) x 29.67] + [65.78 x Y + 193.46] + [(27,123 x Y/(24 x 365 x 60)) x 0.86 x 60 xHPD x DPY]

C = 157,700 C = 3,596 x Y + 235,146 

Batch oil-emulsionbreaking with gravityflotation [requiressulfuric acid, alum, andpolymer feed systems]

See dissolved air flotation. A = [(0.65 x Y + 49.7) x HPD x DPY x 0.047] + [HPD x DPY x 29.67] + [(DPY/5) x 29.67] +

[0.022 x Y x 60 x HPD x DPY x 0.86]

C = 17,204 x Y + 2,000,000

Chromium reductionsystem, sodiummetabisulfite

A = [2.4225 x HPD x DPY x 0.047] + [0.002608 x Y x 60 x HPD x DPY] + [(HPD/8) x DPY 

29.67] + [(DPY/5) x 29.67]

C = 20,892 C = 261.7 x Y + 24,249 

Alkaline chlorinationwith hypochlorite feedsystem (for cyanidedestruction)

A = [4.845 x HPD x DPY x 0.047] + [0.012418 x Y x HPD x DPY x 60] + [0.125 x HPD x DP

x 29.67] + [(DPY/5) x 29.67]

C = 28,862 C = 29,793 x Y0.19 

Chelation breaking withdithiocarbamatetreatment

A = [2.4225 x HPD x DPY x 0.047] + [0.000583 x Y x 60 x HPD x DPY] + [(HPD/8) x DPY 

29.67] + [(DPY/5) x 29.67]

C = 20,892 C = 261.7 x Y + 24,249 
11-47

Table 11-13 (Continued)

11.0 - Costs of Techno

Equipment Equation 

Chemical precipitation[requires sulfuric acid,caustic, and polymerfeed systems]

A = [0.932 x HPD x DPY x 0.047] + [(DPY/5) x 29.67] + [(HPD/8) x DPY x 29.67] C = 8,900 C = 626.6 x Y + 8,550 A = [[(0.0571 x Y) + 0.0123] x HPD x DPY x 0.047] + [(DPY/5) x 29.67] + [(HPD/8) x DPY 

29.67]

C = 784.54 x Y + 34,216

Clarifier, slant-plate(lamella)

A = 2 x (DPY/5) x 29.67 C = 9,740 C = 15,057 C = 74.896 x Y + 31,401 

Filtration, multimedia A = [[(0.0504 x Y) + 1.0139] x HPD x DPY x 0.047] + [(HPD/8) x DPY x 29.67] + [(DPY/5) 

29.67]

C = 35,115 C = 240.85 x Y + 27,269 

Microfiltration systemfor metals removal

A = [(0.3 x Y + 6.3) x HPD x DPY x 0.047] + [3.4 x Y] + [0.5 x HPD x DPY x 29.67] +

[(DPY/5) x 29.67] + [184.2 x Y + 155.2]

C = 74,081 C = 1,728.3 x Y + 69,337 

Sludge thickening A = [0.246 x HPD x DPY x 0.047] + [2 x (DPY/5) x 29.67] 

C = 74.306 x Y x 60 + 3,746A = [3.7 x HPD x DPY x 0.047] + [2 x (DPY/5) x 29.67] C = 2334.8 x Y + 77,429
11.0 - Costs of Techno

Table 11-13 (Continued)	

Equipment Equation 

Filter press, plate-andframe A = [(60 + (30 x DPY x 2)) x NUM] + [FT3 x DPY x 7.48 x 1.95] 

A = [(60 + (60 x DPY x 2)) x NUM] + [FT3 x DPY x 7.48 x 1.95] A = [(60 + (90 x DPY x 2)) x NUM] + [FT3 x DPY x 7.48 x 1.95] C = [1,658.8 x FT3] + 17,505 

aAll costs are calculated in 2001 dollars. Variable Definitions:
C � Direct capital costs (1996 dollars).


A � Annual costs (1996 dollars).


Y � Influent equipment flow (gallons per minute).


HPD � Operating hours per day.


DPY � Operating days per year.


FT3 � Daily cake volume (FT3) from all presses.


IPFLOW � GPH


TANKVOL � Volume of countercurrent rinsing tank (gallons).


CCFLOW � Flow rate after countercurrent rinsing is supplied (gallons per minute).


kW � Kilowatts.


CFT3 � Cake volume (FT3) per cycle per press (assume two cycles per day).


NUM � Number of units.


TSS � Influent TSS concentration (mg/L).


11-48

11.0 - Costs of Technology Bases for Regulations 

11.6.4 Contracting for Off-Site Treatment and Disposal 

The Agency estimated costs for off-site treatment and disposal of various types of 

wastes generated on site. These waste types include: 

� Painting and paint stripping/solvent wastewater;


� Paint sludge;


� Wastewater containing oil and grease and organic pollutants;


� Waste oils/sludges;


� Chromium-bearing wastewater;


� Cyanide-bearing wastewater;


� Chelated metal-bearing wastewater;


� General metal-bearing wastewater; and


� Metal-bearing sludge.


Except for F006 hazardous waste, EPA estimated costs for off-site transportation 

and treatment/disposal of each waste type in dollars per gallon of waste using averages of cost 

data provided in the 1996 MP&M Detailed Survey for off-site disposal of specific wastewater 

streams. EPA applied these costs throughout the cost model using the logic in Table 11-14. 

11.6.5 Feed Systems and Chemical Dosages 

Feed systems are components of almost every option technology. EPA developed 

three types of cost modules for feed systems: treatment-specific, generic, and low-flow. EPA 

determined dosage, equipment, and other design specifics for treatment-specific feed systems, 

whenever data were available. For feed systems with no specific information available, EPA 

developed a generic feed system module, using literature or engineering judgement to select 

dosages and equipment. For feed systems with low-flow treatment systems, EPA developed lowflow polymer, sodium hydroxide, sulfuric acid, alum, lime, and ferric sulfate feed modules, with 

lower fixed capital and energy costs for flow rates of less than 600 gallons per hour. EPA also 

developed lower energy costs for alum feed systems with flow rates below 350 gallons per 

minute. Table 11-15 lists the treatment technologies that use feed systems. 

11-49

11.0 - Costs of Technology Bases for Regulations


Table 11-14	

Logic Used for Off-Site Treatment and Disposal Cost Estimates 

Type of Waste Estimated Cost Data Source 

Painting and paint stripping wastewater $2.85 per gallon Costs for off-site disposal of solventbearing wastewater as reported in the 

1996 MP&M Detailed Survey 

Paint sludge generated by the painting water 

curtain centrifugation system 

$3.70 per gallon Average values reported in the 1996 

MP&M Detailed Surveys for hazardous 

and nonhazardous waste 

Wastewater bearing oil and grease or other 

organic pollutants 

$1.33 per gallon Values reported in the 1996 MP&M 

Detailed Survey 

Waste oil generated by machining coolant 

centrifugation and pasteurization, chemical 

emulsion breaking and gravity oil/water 

separation, dissolved air flotation, and 

ultrafiltration 

$0.86 per gallon Values reported in the 1996 MP&M 

Detailed Survey 

Waste sludge generated by dissolved air flotation $0.86 per gallon Values reported in the 1996 MP&M 

Detailed Survey 

Hexavalent chromium-bearing wastewater $3.51 per gallon Values reported in the 1996 MP&M 

Detailed Survey 

Cyanide-bearing wastewater $5.64 per gallon Values reported in the 1996 MP&M 

Detailed Survey 

Chelated metal-bearing wastewater $1.40 per gallon Values reported in the 1996 MP&M 

Detailed Survey 

Metal-bearing wastewater $2.00 per gallon Values reported in the 1996 MP&M 

Detailed Survey 

Metal-bearing sludge, generated by the sludge 

pressure filtration system and the machining 

coolant centrifugation and pasteurization system 

$1.95 per gallon The value reported in Pollution 

Prevention and Control Technology for 

Plating Operations (4) for F006 

hazardous wastes 

Additional details are provided in Section 6.7.1 of the rulemaking record, DCN 

16023. 

11-50

11.0 - Costs of Technology Bases for Regulations 

Table 11-15 

Treatment Technologies That Use Feed Systems 

Treatment Technology Feed Systems Required 

Chemical emulsion breaking and gravity oil/water separation Sulfuric acid 

Polymer 

Alum 

Dissolved air flotation Lime 

Ferric sulfate 

Polymer 

Batch oil emulsion breaking with gravity flotation Polymer 

Sulfuric acid 

Alum 

Chemical reduction of hexavalent chromium Sulfuric acid 

Sodium metabisulfite 

Cyanide destruction Sodium hydroxide 

Sulfuric acid 

Sodium hypochlorite 

Chemical reduction/precipitation of chelated metals Sulfuric acid 

Dithiocarbamate 

Chemical precipitation Sulfuric acid 

Polymer 

Caustic 

Sources: Pollution Prevention and Control Technology for Plating Operations (4) and MP&M Sampling Data. 

To determine the required chemical dosage for each technology, the Agency used 

either the Pollution Prevention and Control Technology for Plating Operations (4) or chemical 

usage data from sampled MP&M sites with the option technology in place. Table 11-16 lists the 

chemical dosage used to estimate costs and the source from which the dosage was derived. 

Capital and annual costs from feed systems were not reported individually in cost 

model outputs but were added into the overall treatment system capital and annual costs. The 

cost model included the capital and annual costs for the following equipment in the feed system 

capital costs: 

� Raw material storage tank; 

� Day storage tank with mixer; 

� Chemical metering pumps; 

� pH controller; and 

� Supporting piping and valves. 

11-51

11.0 - Costs of Technology Bases for Regulations 

Table 11-16	

Treatment Dosage Information	

Feed system 

Chemical Concentration Required 

(mg/L) 

Data 

Source 

Polymer feed system 20 (4) 

Continuous sodium hydroxide feed system 1,685 (4) 

Continuous hydrated lime feed system 376 (4) 

Continuous sulfuric acid feed system 699 (4) 

Continuous ferric sulfate feed system 74 (5) 

Continuous aluminum sulfate (alum) feed system 648 (5) 

Continuous calcium chloride feed system 830 (4) 

Sources: Pollution Prevention and Control Technology for Plating Operations (4) and MP&M Sampling Data. 

11.6.6 Chemical Emulsion Breaking and Gravity Oil/Water Separation 

EPA estimated costs for chemical emulsion breaking and gravity oil/water 

separation systems to separate and remove oil and grease and TSS. The Agency assumed that 

model sites commingled all oil-bearing wastewater streams prior to treatment. Table 11-12 lists 

the unit operations that discharge wastewater streams that feed oil removal treatment units. 

For chemical emulsion breaking systems, the module included capital and annual 

costs for the following equipment: 

� Flow equalization tank;


� Two emulsion breaking tanks;


� Two mixers;


� Sulfuric acid feed system (see Section 11.6.5);


� Polymer feed system (see Section 11.6.5);


� Alum feed system (see Section 11.6.5);


� Sodium hydroxide feed system (see Section 11.6.5); and


� Wastewater pumps.


Emulsion breaking was followed by oil removal using a coalescent plate 

separator. For oil removal systems, EPA estimated capital and annual costs for the following 

equipment: 

� Feed pumps; 

� Belt skimmer; and 

� Oil/water separator. 

11-52

11.0 - Costs of Technology Bases for Regulations 

Direct annual costs included O&M labor and materials, energy costs, raw 

materials (e.g., sulfuric acid, alum, polymer, sodium hydroxide), and waste oil disposal costs. 

EPA also included costs for off-site reclamation of waste oil. EPA also estimated waste oil 

generation to be 7.1 percent of the influent flow, based on MP&M survey data. 

11.6.7 Dissolved Air Flotation 

For the Shipbuilding Dry Dock Subcategory, EPA estimated costs for dissolved 

air flotation systems to separate and remove oil and grease, suspended solids, and organic 

pollutants. The Agency assumed that shipbuilding model sites commingled all oil-bearing 

wastewater streams prior to treatment. 

The module included capital and annual costs for the following equipment: 

� Flow equalization tank; 

� Feed pumps; 

� Oil/water separator; 

� Chemical treatment tank; 

� Lime feed system (see Section 11.6.5); 

� Ferric sulfate feed system (see Section 11.6.5); 

� Polymer feed system (see Section 11.6.5); 

� Dissolved air flotation system with pressure tank and programmable logic 

controller (PLC); 

� Oil storage tank; and 

� Final pH adjustment tank. 

Direct annual costs included O&M labor and materials, energy costs, raw 

materials (e.g., hydrated lime, ferric sulfate, polymer), and waste oil and sludge disposal costs. 

EPA also estimated costs for off-site reclamation of the waste oil and sludge. Hydrated lime and 

ferric sulfate flows were added to the discharge flow, while polymer volume was considered 

negligible. EPA estimated generation of waste oil and sludge as 7.1 and 0.03 percent of the 

influent flow, respectively, based on the MP&M survey data. Because dissolved air flotation 

systems are not typically used for flow rates of less than 265 gallons per hour (gph), EPA 

estimated costs for ultrafiltration oil removal for model sites with flows of less than 265 gph. 

11-53

11.0 - Costs of Technology Bases for Regulations 

11.6.8 Ultrafiltration System for Oil Removal 

EPA estimated costs for ultrafiltration systems to separate and remove oil and 

grease, suspended solids, and organic pollutants. This technology differs from chemical 

emulsion breaking with oil/water separation, which was used to develop Option 6 costs (see 

11.6.6). The Agency assumed that model sites commingled all oil-bearing wastewater streams 

prior to treatment and that flow rates greater than the maximum costed system (406 gallons per 

minute) required multiple systems. 

The module included capital and annual costs for the following equipment: 

� Spiral-wound membrane filtration modules; 

� Process and chemical tanks; 

� Steel skid; 

� Recirculation tank; 

� Recirculation pump; 

� Bag filter; 

� Fix-mounted cleaning system; 

� Sludge pump; and 

� Electrical components (pH control/monitoring, temperature control, flow 

meter, pressure gauges). 

Direct annual costs included O&M labor and materials, energy costs, cleaning 

chemicals, membrane replacement, and waste oil disposal costs. EPA estimated costs for off-site 

reclamation of waste oil. EPA estimated waste oil generation as 5.2 percent of the influent flow, 

based on MP&M survey data. 

11.6.9 Batch Oil Emulsion Breaking with Gravity Flotation 

EPA estimated costs for batch oil emulsion breaking with gravity flotation 

systems to separate and remove oil and grease, suspended solids, and organic pollutants. This 

technology differs from chemical emulsion breaking with oil/water separation, which was used to 

develop Option 6 costs (see 11.6.6). Gravity flotation uses a large tank, with oil recovered over 

weirs, and is typically seen at large sites such as automotive manufacturing. The Agency 

assumed that model sites commingled all oil-bearing wastewater streams prior to treatment. 

11-54

11.0 - Costs of Technology Bases for Regulations 

Although batch emulsion breaking with gravity flotation is not part of the MP&M 

technology options, EPA estimated baseline operating costs and pollutant removals for sites that 

had this technology in place at baseline. The module included capital and annual costs for the 

following equipment: 

� Polymer feed system (see Section 11.6.5);


� Sulfuric acid feed system (see Section 11.6.5);


� Alum feed system (see Section 11.6.5);


� Two mechanically cleaning bar screens;


� Three batch wastewater treatment tanks;


� Two segregated waste tanks;


� Three skim and saleable oil storage tanks;


� Two oil cooking tanks;


� Pumps;


� One air compressor;


� Six mixers (segregation, saleable oil, and oil cooker tanks); and


� Ancillary equipment (pipes and valves, heat trace, controls, and


programmable logic controller (PLC)). 

Direct annual costs included O&M labor, energy costs, raw materials (e.g., 

polymer, sulfuric acid, alum), and waste oil disposal costs. EPA also estimated costs for off-site 

reclamation of waste oil. Flows from sulfuric acid and alum were added to the treatment flow, 

while the polymer volume was considered negligible. EPA assumed the model sites discharged 

treatment effluent to the chemical precipitation and sedimentation system. EPA estimated 

generation of waste oil as 2.2 percent of the influent flow, based on MP&M survey data. This 

technology is typically used for flow rates of greater than 6,000 gallons per hour, whereas 

dissolved air flotation is used for flow rates of between 265 and 6,000 gallons per hour and 

ultrafiltration for oil removal for flow rates of less than 265 gallons per hour. 

11.6.10 Chemical Reduction of Hexavalent Chromium 

EPA estimated costs for batch and continuous systems to reduce hexavalent 

chromium to trivalent chromium prior to chemical precipitation and sedimentation. Note that the 

sedimentation portion of this treatment is discussed in Section 11.6.14. The Agency assumed 

that model sites commingled all chromium-bearing wastewater streams prior to treatment and 

that all chromium in the wastewater was in the hexavalent form. 

The Agency estimated costs for batch treatment for flow rates of less than or 

equal to 600 gallons per day and continuous systems for flow rates of greater than 600 gallons 

per day. The module included capital and annual costs for the following equipment: 

� Fiberglass reaction tank; 

� Mixer; 

� Sulfuric acid feed system; 

11-55

11.0 - Costs of Technology Bases for Regulations 

� Sodium metabisulfate feed system;


� Flow equalization tank;


� Effluent pump; and


� pH and oxidation-reduction potential (ORP) meters.


Direct annual costs included O&M labor and materials, energy costs, and raw 

materials (e.g., sulfuric acid, sodium metabisulfite). EPA based flow-dependent costs on the 

volume of wastewater from chromium-bearing unit operations flowing into the system, before 

treatment chemicals were added to the flow. EPA assumed model sites discharged the treatment 

effluent to the chemical precipitation and sedimentation system. 

11.6.11 Cyanide Destruction 

EPA estimated costs for batch and continuous alkaline chlorination systems to 

destroy cyanide prior to chemical precipitation and sedimentation. The Agency assumed that 

model sites commingled all cyanide-bearing wastewater streams prior to treatment and did not 

send cyanide-free wastewater streams to the cyanide destruction system. 

The Agency estimated costs for batch treatment for flow rates of less than or equal 

to 600 gallons per day and continuous systems for flow rates of greater than 600 gallons per day. 

The module included capital and annual costs for the following equipment: 

� Two reaction tanks (batch treatment uses a single tank, with the second 

tank operating as a batch-holding tank); 

� Mixers; 

� Sodium hydroxide feed system; 

� Sulfuric acid feed system; 

� Sodium hypochlorite feed system; 

11-56

11.0 - Costs of Technology Bases for Regulations 

� Effluent pumps; and 

� pH and ORP meters. 

Direct annual costs included O&M labor and materials, energy costs, and raw 

materials (e.g., sodium hydroxide, sulfuric acid, sodium hypochlorite). EPA based flowdependent costs on the volume of wastewater from cyanide-bearing unit operation flowing into 

the system, before treatment chemicals were added to the flow. The Agency assumed model sites 

discharged the treatment effluent to the chemical precipitation and sedimentation system. EPA 

also assumed that all other pollutant concentrations remained unchanged in this treatment unit. 

11.6.12 Chemical Reduction/Precipitation of Chelated Metals 

EPA estimated costs for batch and continuous chemical reduction/precipitation of 

chelated metal systems to break and precipitate electroless plating complexes (e.g., copper or 

nickel complexes) prior to chemical precipitation and sedimentation. The Agency assumed that 

model sites commingled all chelated metal-bearing wastewater streams prior to treatment. 

The Agency estimated costs for batch treatment for flow rates of less than or equal 

to 600 gallons per day and continuous systems for flow rates of greater than 600 gallons per day. 

The module included capital and annual costs for the following equipment: 

� Fiberglass reaction tank;


� Mixer;


� Sulfuric acid feed system;


� Dithiocarbamate feed system (see Section 8.4.4);


� Flow equalization tank;


� Effluent pump; and


� pH and ORP meters.


Direct annual costs included O&M labor and materials, energy costs, and raw 

materials (e.g., sulfuric acid, dithiocarbamate). EPA based flow-dependent costs on the volume 

of wastewater from chelated metal-bearing unit operations flowing into the system, before 

treatment chemicals were added to the flow. The Agency assumed that model sites discharged 

treatment effluent to the chemical precipitation and sedimentation system. Based on analytical 

data for the systems EPA sampled, EPA assumed that concentrations of carbon disulfide and 

dithiocarbamate increased across the system. 

11.6.13 Chemical Precipitation 

The Agency estimated costs for continuous chemical precipitation systems. EPA 

estimated costs for low-flow systems for model sites with influent flow rates of less than or equal 

to 300 gallons per hour. EPA assumed that the model sites commingled all MP&M wastewater 

generated for treatment by this technology, except for wastewater from the Oily Wastes, 

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11.0 - Costs of Technology Bases for Regulations 

Shipbuilding Dry Dock, and Railroad Line Maintenance Subcategories. In addition, EPA 

assumed that sites would contract for off-site disposal of solvent-bearing wastewater. 

The module included capital and annual costs for the following equipment:


� Sulfuric acid feed system (see Section 11.6.5);


� Polymer feed system (see Section 11.6.5);


� Caustic feed system (see Section 11.6.5);


� Equalization tank;


� Rapid-mix tank for precipitation;


� Flocculation tank;


� Final pH-adjustment tank;


� System feed pumps; and 


� Rapid and flocculation mixers.


Direct annual costs included O&M labor, energy costs, and raw materials (e.g., 

sulfuric acid, polymer, caustic). The module assumed that the amount of TSS leaving the 

chemical precipitation system was equivalent to the sum of influent TSS and the dissolved solids 

that are converted to suspended solids when caustic is added to the wastewater. The approach for 

calculating suspended solids generated from dissolved solids is documented in Section 6.7.1 of 

the rulemaking record, DCN 16363. EPA estimated that the effluent flow rate from this system 

equaled the influent flow rate because additional flow from treatment chemical addition was 

negligible. EPA designed the cost model to include recycled water from the sludge thickener and 

filter press. In addition, the Agency assumed that model sites discharged effluent from the 

chemical precipitation system to either clarification or microfiltration. 

11.6.14 Sedimentation by Slant-Plate Clarifier 

The Agency estimated costs for sedimentation using slant-plate (lamella) clarifier 

systems. EPA estimated costs for low-flow systems for model sites with influent flow rates of 

less than or equal to 600 gallons per hour. EPA designed this system to treat effluent from the 

chemical precipitation system. 

The module included capital and annual costs for the following equipment: 

� Slant-plate clarifier; and 

� One-time training costs for operators to meet MP&M clarifier limits 

instead of the baseline 40 CFR 433 Metal Finishing effluent guideline 

limits (see Section 24.6.1, DCN 17906, of the rulemaking record). 

EPA estimated costs associated with achieving long-term average effluent 

concentrations for all pollutants treated by chemical precipitation with clarification (see Section 

10.3). EPA calculated the amount of sludge generated using model-calculated site-specific 

11-58

11.0 - Costs of Technology Bases for Regulations 

influent pollutant concentrations for the commingled wastewater. The Agency assumed the 

sludge was 3 percent solids (5) and was discharged to a sludge-thickening tank (see Section 

11.6.17) and that model sites discharged treatment effluent to surface water or a POTW. Direct 

annual costs included maintenance labor and materials. EPA included costs for operating labor 

in the chemical precipitation module and included costs for pumps in the chemical precipitation 

and the sludge-thickening modules. 

11.6.15 Multimedia Filtration 

The Agency estimated costs for a multimedia filter to continuously remove 

filterable suspended solids. The system was designed as a polishing step for effluent from the 

clarifier. Although EPA did not include this technology in the MP&M technology options, it 

estimated baseline operating costs and pollutant removals for sites that had multimedia filters in 

place at baseline. 

The module included capital and annual costs for the following equipment: 

� Multimedia filter skid; 

� Holding tank for clarifier effluent (clear well); and 

� Media filter feed pump. 

Based on data collected during an MP&M sampling episode, the Agency assumed 

filter backwash to be 1.2 percent of the influent flow to the chemical precipitation unit and that 

model sites discharged filtrate from this system to surface water or a POTW. Direct annual costs 

included O&M labor and energy costs. EPA incorporated waste disposal costs for solids at sites 

operating multimedia filters. 

11.6.16 Microfiltration for Solids Removal 

The Agency estimated costs for microfiltration for solids separation, assuming 

that flow rates of greater than the maximum costed system (406 gallons per minute) required 

multiple systems. 

The module included capital and annual costs for the following equipment: 


� Tubular membrane filtration modules; 


� Carbon steel skid; 


� Recirculation tank; 


� Recirculation pump; 


� Air back pulse system; 


� Cleaning system; 


11-59

11.0 - Costs of Technology Bases for Regulations 

� Sludge pump; and 

� All associated instruments and controls. 

EPA calculated the amount of sludge generated by this system using modelcalculated site-specific influent pollutant concentrations for the commingled wastewater. Based 

on data collected during an MP&M sampling episode, the Agency assumed the sludge was 3.2 

percent solids and was discharged to a sludge-thickening tank (see Section 11.6.17). EPA 

assumed model sites discharged microfiltration effluent to surface water or a POTW. Direct 

annual costs included O&M labor and materials (e.g., replacement membranes, cleaning 

chemicals) and energy costs. 

11.6.17 Sludge Thickening 

The Agency estimated costs for sludge thickening by gravity settling for the 

sludge discharged from slant-plate clarifiers and microfilters. EPA assumed the sludgethickening system discharged 60 percent of influent flow as sludge, thus increasing the solids 

content of the sludge from 3 to 5 percent for clarifier sludges and from 3.2 to 5.3 percent for 

microfiltration sludges (6). EPA assumed that the model sites discharge thickened sludge to a 

pressure filter for further dewatering (see Section 11.6.18), and that they returned the remaining 

40 percent of influent flow (supernatant) to the chemical precipitation system. The module 

included capital and annual costs for the following equipment: 

� Sludge-thickening unit (package system); and 

� Clarified water return pump. 

Direct annual costs included O&M labor and energy costs. 

11.6.18 Sludge Pressure Filtration 

The Agency estimated costs for the plate-and-frame filter presses, estimating the 

number needed to increase the solids content of the sludge from approximately 5 to 35 percent 

(5). The module included capital and annual costs for the following equipment: 

� Recessed plate or plate-and-frame filter press; and 

� Two double-diaphragm sludge pumps. 

Direct annual costs included O&M labor and sludge disposal costs. EPA assumed 

model sites contracted for off-site disposal of the denatured sludge (see Section 11.3.2 and Table 

11-4). EPA also assumed these sites discharged the filtrate from this system to the chemical 

precipitation and sedimentation system. 

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11.0 - Costs of Technology Bases for Regulations 

11.7 References 

1.	 RS Means Building Construction Cost Data, 56th Annual Edition. 1998, page 

594. Historical Cost Indexes. 

2. Chemical Marketing Reporter. December 1997. 

3. U.S. Bureau of Labor Statistics. Monthly Labor Review. 1997. 

4.	 Cushnie, George C., CAI Engineering (prepared for NCMS/NAMF). Pollution 

Prevention and Control Technology for Plating Operations. 

5.	 Cherry, Kenneth F. Plating Waste Treatment. Chapter 3. Ann Arbor Sciences 

Publishers, Inc., Ann Arbor, MI, 1982. 

6.	 Eckenfelder, W. Wesley. Principals of Water Quality Management. Chapter 11. 

CBI Publishing Company, 1980. 

11-61

11.0 - Costs of Technology Bases for Regulations

11-62

Figure 11-1. Relationship Between In-Process and Endof-Pipe Technologies and Practices
11.0 - Costs of Technology Bases for Regulations

11-63

Figure 11.2. Components of Total Capital Investments
11.0 - Costs of Technology Bases for Regulations

11-64

Figure 11-3. pply End-of-Pipe Technologies and Practices for the Following

Subcategories: General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed

Wiring Board, and Steel Forming and Finishing

Logic Used to A
11.0 - Costs of Technology Bases for Regulations

11-65

Figure 11-4. pply End-of-Pipe Technologies

and Practices for the Following Subcategories: Oily Wastes,

Railroad Line Maintenance, and Shipbuilding Dry Dock

Logic Used to A
11.0 - Costs of Technology Bases for Regulations 

11-66

Figure 11-5. Example Treatment Facility for General Metals Subcategory Direct Discharger 
12.0 - Pollutant Loading and Reduction Estimates 

12.0 POLLUTANT LOADING AND REDUCTION ESTIMATES 

This section describes EPA’s approach for modeling the MP&M industry annual 

pollutant loadings and removals for each technology option described in Section 9.0. In general, 

this approach consists of three major steps: 

1.	 Estimate baseline pollutant loading from each MP&M model site. 

Wastewater discharged from MP&M unit operations goes to either on-site 

treatment, publicly owned treatment works (POTWs), or directly to 

surface waters. EPA used survey data from each model site to determine 

the destination of each waste stream. EPA estimated discharged pollutant 

concentrations from: EPA sampling data, industry-supplied data, and 

existing limitations. EPA estimated loadings by multiplying the 

discharged pollutant concentrations by the discharged flow. The baseline 

pollutant loading refers to the total amount of pollutants discharged from 

the model site to surface waters or POTWs for the base year of the survey. 

2.	 Estimate baseline pollutant loadings for the MP&M industry. EPA 

multiplied the site-specific baseline wastewater loadings by the 

corresponding statistically derived weighting factors (see Section 3.0) for 

each model site. EPA summed the weighted loadings across all sites to 

estimate industry-wide baseline wastewater pollutant loadings. 

3.	 Estimate option-specific pollutant loadings and removals for the MP&M 

industry. The option-specific pollutant loadings represent the total 

industry pollutant loadings in MP&M wastewater that would be 

discharged to surface water or POTWs after complying with a particular 

regulatory option. 

Key terms for pollutant loadings and removals are defined below: 

� Model sites - Facilities used in the EPA Costs & Loadings Model to 

represent the industry nationally. These facilities responded in the MP&M 

detailed survey that they discharge MP&M wastewater. 

� Long-term average - Average pollutant concentrations achieved over a 

period of time by a facility, subcategory, or technology option. 

� Baseline concentration - Pollutant concentration (milligrams per liter 

(mg/L)) in wastewater currently discharged to surface water or a POTW. 

If the facility has wastewater treatment in place, the baseline concentration 

is the pollutant concentration in wastewater discharged from final 

treatment. If the facility does not have treatment in place, the baseline 

concentration is the commingled concentration of all unit operation 

wastewater discharged. 

12-1

12.0 - Pollutant Loading and Reduction Estimates 

� Baseline loadings - Modeled pollutant loadings, in pounds per year 

(lbs/yr), in MP&M wastewater currently being discharged to surface water 

or to POTWs for the base year of the model site’s survey. These loadings 

reflect wastewater treatment in place at model sites in the year 1996. 

� Option loadings - Also referred to as post-compliance loadings. Pollutant 

loadings, in lbs/yr, in MP&M wastewater that would be discharged to 

surface water or to POTWs after complying with a regulatory option. EPA 

calculated the loadings assuming that all MP&M facilities would achieve 

long-term average effluent pollutant concentrations associated with the 

technology options. 

� Pollutant reductions - The difference between baseline loadings and option 

loadings for each regulatory option. 

� Weighting factor - Statistically derived values for each model site used to 

reflect all facilities in the MP&M industry. (See Section 10.0, DCN 16118 

of the rulemaking record). EPA multiplied the baseline or option loadings 

for each model site by its corresponding weighting factor to estimate 

industry-wide baseline or option loadings. 

� Toxic pound-equivalents - Pollutant loadings, in pound-equivalents per 

year (PE/yr), in MP&M wastewater. A pound-equivalent (PE) is a pound 

of pollutant weighted for its toxicity to human and aquatic life. 

Unless specified otherwise, EPA estimated baseline pollutant loadings and 

reductions for all pollutants identified in Section 7.0 as pollutants of concern. EPA used data 

from several sources to estimate pollutant loadings and reductions, including data from EPA 

sampling episodes, the existing 40 CFR 413 and 433 regulations, EPA’s Permit Compliance 

System (PCS) database, pretreatment coordinators, states, and industry. See Section 3.0 for 

additional discussion on EPA’s data collection efforts. 

Note that all tables appear at the end of this section. 

12.1 Estimation of Unit Operation Wastewater Pollutant Concentrations 

EPA used sampling data and industry-supplied data (included in Sections 5.0 and 

15.0 in the rulemaking record) to estimate subcategory-specific wastewater pollutant 

concentrations for each of the MP&M unit operations that generate wastewater at MP&M model 

sites. 

12.1.1 Unit Operation Wastewater Data Collection 

EPA’s “unit operations database” comprises EPA sampling data and industrysupplied data. EPA collected unit operations wastewater discharged from 56 sites for 96 unit 

12-2

12.0 - Pollutant Loading and Reduction Estimates 

operations. Industry supplied EPA with wastewater data for 15 unit operations. Throughout this 

section, the terms “sampling point” and “sample” refer to the following: 

� Sampling point - The physical location at which samples are collected. 

Example sampling points include a wastewater treatment influent stream, 

an electroplating bath, or a cleaning rinse. A sampling point captures the 

wastewater characteristics of a specific unit operation or a group of unit 

operations. 

� Sample - The unique volume of wastewater collected for analysis at a 

sampling point. A sample can include several different aliquots collected 

for analysis of multiple parameters. Each sample represents a unique 

period of time. EPA typically collected multiple samples from sampling 

points that represented flowing waste streams (e.g., wastewater treatment 

systems, rinses). 

12.1.2	 Calculation of Pollutant Concentrations for Each Unit Operation for Each 

Sampling Point from EPA or Industry-Supplied Sampling Data 

EPA collected both grab and composite samples to characterize MP&M unit 

operations. EPA generally collected grab samples for nonflowing streams where the pollutant 

concentrations were not expected to vary significantly over the sampling period. EPA generally 

collected composite samples (typically 24-hour composites) for flowing streams. For oil and 

grease, EPA collected a series of grab samples as specified by the analytical method. In some 

cases, EPA had to mathematically aggregate two or more samples to obtain a single value that 

could be used in calculations to represent a single waste stream. This occurred with field 

duplicates and grab samples collected over time. For each sample point, EPA aggregated field 

duplicates first, grab samples second, and multiple-day samples third. In cases where the 

sampled pollutants were not detected in the wastewater, EPA used the sample-specific detection 

limit as the pollutant concentration. EPA calculated pollutant concentrations for each sampling 

point using the following approach: 

� Average the duplicate sample concentrations. As discussed in Section 3.0, 

EPA collected duplicate samples at many sampling points as a quality 

control measure. Industry-supplied data submitted with comments on the 

MP&M proposal also contained duplicate samples. Where duplicate 

samples were collected at a sampling point, EPA averaged the 

concentrations of the two samples to develop a single pollutant profile for 

the sampling point for that 24-hour period. 

� Average the grab sample aliquot concentrations. EPA averaged the 

concentrations of all grab sample aliquot fractions (i.e., for oil and grease) 

collected during a 24-hour period in order to estimate a representative 24-

hour composite for that parameter. 

12-3

12.0 - Pollutant Loading and Reduction Estimates 

� Average multiple sample concentrations for each sampling point. For 

flowing wastewater streams (e.g., rinses), EPA and industry typically 

collected multiple samples at a single sample point to account for 

variability over time of the discharges from these streams. EPA averaged 

the concentrations of the composite or grab samples collected on each day 

at the same sampling point. For example, if EPA collected three one-day 

composite samples of an acid treatment rinse at the same sampling point, it 

averaged the concentrations of each pollutant on each of the three days to 

develop a single pollutant profile for the sampling point for that episode. 

12.1.3	 Estimation of Pollutant Concentrations for Each Subcategory and Unit 

Operation 

EPA estimated pollutant concentrations for each unit operation performed in a 

given subcategory (as reported in the MP&M detailed surveys). For example, EPA estimated 

pollutant concentrations for UP-4 (acid treatment without chromium) separately for sites in the 

General Metals Subcategory and for sites in the Metal Finishing Job Shops Subcategory. For 

electroplating and electroless plating operations, EPA estimated the pollutant concentration(s) of 

the applied metal(s) separately from other bath constituents to account for the dependancy of 

these operations on high concentrations of the applied metal(s). EPA used the following steps to 

estimate the subcategory-specific unit operation wastewater pollutant concentrations at model 

MP&M sites: 

1.	 Identified, for each subcategory, all unit operations reported in the detailed 

surveys (see Section 12.1.3.1); 

2.	 Estimated pollutant concentrations for each unit operation in a given 

subcategory (see Section 12.1.3.2); 

3.	 Estimated an applied metal concentration in the bath and in the rinse for 

each electroplating and electroless plating operation for each subcategory 

(see Section 12.1.3.3); and 

4.	 Modeled pollutant concentrations for each model site unit operation (see 

Section 12.1.3.4). 

These steps are described in the following subsections. 

12.1.3.1 Identification of Unit Operations Reported in the Detailed Surveys 

EPA queried the MP&M detailed survey database to identify all unit operations 

discharging wastewater, as well as all types of electroplating and electroless plating operations 

(defined by applied metal). 

12-4

12.0 - Pollutant Loading and Reduction Estimates 

12.1.3.2	 Estimation of Wastewater Pollutant Concentrations for Each Unit 

Operation/Subcategory Combination 

For each subcategory, EPA calculated the average wastewater pollutant 

concentrations for each unit operation. For example, EPA averaged the wastewater pollutant 

concentrations for all acid cleaning operations (using the wastewater pollutant concentrations 

calculated at each sampling point) at facilities in the General Metals Subcategory. EPA also 

separately estimated wastewater pollutant concentrations for unit operations for the “zinc plater” 

segments of the Metal Finishing Job Shops and General Metals Subcategories. 

Additionally, EPA combined the sampling data for all metal-bearing 

subcategories (with the exception of data from printed wiring board facilities

1

) and calculated the 

average wastewater pollutant concentrations for each unit operation. EPA did the same for all 

oil-bearing subcategories. EPA used the average unit operation concentrations calculated for 

metal-bearing subcategories and oil-bearing subcategories to estimate pollutant concentrations 

from unit operations in subcategories with no unit operation concentration data. 

Based on comments received on the MP&M proposed rule, EPA modified the 

calculation of unit operation wastewater pollutant concentrations for the following pollutants: 

� Cyanide. EPA set the cyanide pollutant concentration equal to zero for all 

non-cyanide-bearing unit operation wastewaters. (EPA sampling data 

included incidental cyanide concentrations for non-cyanide-bearing unit 

operations due to drag-out or unspecified sources.) 

� Total Sulfide. EPA estimated wastewater pollutant concentrations for total 

sulfide using all results from Phase I and II sampling (Method 376.1) and 

an average of the results from Methods 376.2 and 4500-S2E from Phase 

III sampling. EPA used all three analytical methods (376.1, 376.2, and 

4500-S2E) to measure total sulfide in Phase III sampling (i.e., postproposal sampling); however, EPA did not use sampling data from 

Method 376.1 from Phase III due to possible interferences. 

� Oil and Grease. EPA estimated wastewater pollutant concentrations for 

oil and grease using all Phase II and III data, but included Phase I data only 

in cases where no Phase II or III data were available for that unit operation 

in the Oily Wastes, Railroad Line Maintenance, and Shipbuilding Dry 

Dock Subcategories. EPA used a different analytical method to measure 

for oil and grease during Phase I sampling than during Phase II and III 

sampling. EPA used Method 413.2 during Phase I sampling (a freonextractable method). EPA used Method 1664 during Phase II and Phase 

III sampling (measures oil and grease as hexane extractable material). 

1

EPA omitted data from the Printed Wiring Board Subcategory due to the high concentration of specific metals (i.e., 

copper) common to primarily the printed wiring board industry. 

12-5 
12.0 - Pollutant Loading and Reduction Estimates 

� Sodium, Calcium, and Total Dissolved Solids. EPA set the wastewater 

pollutant concentrations for these pollutants equal to zero for all unit 

operation wastewaters in all subcategories. EPA set the pollutant 

removals for sodium and calcium equal to zero in response to Phase I 

comments on the wide use of these two treatment chemicals, which results 

in elevated removals estimates. EPA set the loads removals for total 

dissolved solids (TDS) equal to zero because many treatment chemicals 

also elevate TDS concentrations. 

Based on comments received on the MP&M proposed rule, EPA modified the 

calculation of unit operation wastewater pollutant concentrations for the following specific cases: 

� Testing. EPA used data from radiator pressure testing operations to 

estimate unit operation wastewater pollutant concentrations for all testing 

unit operations at model sites in the oil-bearing wastewater subcategories 

and hydraulic testing unit operations in the metal-bearing wastewater 

subcategories. EPA used dye penetrant testing data to estimate wastewater 

pollutant concentrations in all other types of testing in the metal-bearing 

wastewater subcategories. EPA did not include the other EPA-sampled 

testing data (from alpha-case detection testing and engine performance 

testing coolant operations) based on the unique composition of wastewater 

for these site-specific operations. 

� Unit Operations with a Greater Rinse Concentration than Bath 

Concentration. After averaging sampling data across samples for a 

particular sampling point, EPA found instances where the modeled bath 

had a lower concentration than for the same pollutant in the associated 

rinse. In these cases, EPA set the bath wastewater pollutant concentration 

equal to the rinse wastewater pollutant concentration. 

Based on comments received on the MP&M proposed rule, EPA modified the 

calculation of unit operation wastewater pollutant concentrations for certain pollutants in the 

Non-Chromium Anodizing Subcategory: 

� Chromium, Hexavalent Chromium, Lead, and Cadmium. EPA set the 

wastewater pollutant concentrations for these pollutants equal to zero for 

all unit operation wastewaters in the Non-Chromium Anodizing 

Subcategory. EPA defined the Non-Chromium Anodizing Subcategory as 

sites that have no chromium present in any operation on site. Therefore, 

EPA did not expect chromium or hexavalent chromium to be present at 

non-chromium anodizing facilities. EPA also did not expect lead or 

cadmium to be used in unit operations at non-chromium anodizing 

facilities based on the metal types processed by this subcategory. 

12-6

12.0 - Pollutant Loading and Reduction Estimates 

For further details, refer to the memorandum entitled “MP&M Pollutant Loadings Methodology 

Changes from Proposal” located in the rulemaking record (Section 16.7, DCN 16764). 

12.1.3.3 Estimation of Applied Metal Concentrations Using Available Analytical Data 

While the pollutant concentrations in many MP&M unit operations are somewhat 

dependent on the type of metal processed, pollutant concentrations are heavily dependent on the 

applied metal in the electroplating and electroless plating operations. For example, chromium 

electroplating operations and rinses contain higher concentrations of chromium than other 

metals, while electroless nickel plating operations and rinses contain higher concentrations of 

nickel than other metals. EPA estimated the pollutant concentrations of the plated metal(s), 

referred to as “applied” metals, separately from other constituents in the bath and rinse to account 

for the dependency of the pollutant concentrations in these operations and rinses on these 

metal(s). When developing the model pollutant concentrations for these two unit operations, 

EPA designated the metal(s) applied to the surface of the product as the “applied metals” to 

distinguish them from other nonplated metals in the process bath. EPA also designated these 

metals that wash off the product during the process rinse as the “applied metals” in the rinse. 

To more adequately represent the metals concentrations in the wastewater from 

electroplating and electroless plating operations, EPA used a different approach for applied 

metals and other plating bath constituents in these operations. Due to budget constraints, EPA 

did not obtain sampling data for every type of plating solution and rinse reported in the detailed 

surveys and was therefore unable to estimate separately the pollutant concentrations for each type 

of plating. EPA modeled the pollutant concentrations in electroplating and electroless plating 

solutions using the following approach: 

1.	 EPA calculated the total applied metal concentrations for each plating bath 

for which EPA had collected data. If a sampling point had two applied 

metals (e.g., zinc and cobalt), the two pollutant concentrations were 

summed to get a total applied metal concentration. If a sampling point had 

one applied metal, the concentration for that metal was the total applied 

metal concentration. 

2.	 For each subcategory, EPA calculated the median total applied metal 

concentration for all plating baths for which EPA had sampling data. EPA 

calculated these median concentrations separately for electroplating and 

electroless plating baths. EPA then modeled the total metal concentration 

in the bath at the model site as the median concentration of total metals for 

which EPA had data. Note that the Agency had sufficient data to estimate 

the total applied metal concentration on a subcategory-specific basis, but 

not on a pollutant-specific basis. For subcategories with no available 

applied metal data, EPA used the median of all total applied metal 

concentration data across all subcategories. 

12-7

12.0 - Pollutant Loading and Reduction Estimates 

3.	 EPA calculated the average concentration for all nonapplied pollutants 

across the plating baths (separating electroplating from electroless plating 

baths). For example, EPA calculated the cadmium concentration in all 

baths other than cadmium electroplating baths. EPA then modeled the 

concentration of the nonapplied pollutants as the average concentration for 

the pollutant across the plating baths. 

EPA followed the same approach for estimating pollutant concentrations in 

electroplating and electroless plating unit operation rinses. For further detail, refer to the 

memorandum entitled “MP&M Pollutant Loadings Data Transfer for Base/Applied Metals” 

located in the rulemaking record (Section 16.7, DCN 16763). 

12.1.3.4 Modeling of Pollutant Concentrations for Each Model Site Unit Operation 

To estimate the pollutant concentrations for each model site unit operation, EPA 

first identified the unit operations performed by the model sites in each subcategory. For unit 

operations for which it had collected pollutant concentration data, EPA modeled the wastewater 

pollutant concentrations using the corresponding unit operation average wastewater pollutant 

concentrations calculated from sampling data for that unit operation in the same subcategory. 

For example, EPA calculated the average concentrations for all pollutants of concern identified 

in alkaline cleaning operations in the General Metals Subcategory, and applied these average 

concentrations to all alkaline cleaning operations reported in the surveys for this subcategory. 

When EPA did not have pollutant concentration data for a unit operation within a 

subcategory, EPA transferred pollutant concentrations from unit operations expected to have 

similar wastewater characteristics, based on process considerations. Process considerations 

include the following: the purpose of the unit operation (e.g., metal removal, contaminant 

removal); the purpose of the process water use (e.g., contact cooling water, cleaning solution, 

rinse water); and typical bath additives (e.g., acids, organic solvents, metal salts). EPA 

transferred available pollutant concentration data to the model sites using the following 

hierarchy: 

1.	 If EPA sampled the same unit operation bath (or rinse) at facilities in more 

than one subcategory, including the same subcategory as the model site, 

the Agency used available analytical data for the same operation in the 

same subcategory to estimate wastewater pollutant concentrations for the 

model site unit operation. For example, if available analytical data for a 

unit operation exist for both the General Metals and the Metal Finishing 

Job Shops Subcategories, EPA transferred data from only the General 

Metals Subcategory to model the wastewater pollutant concentrations for 

the same unit operation at a model site in the General Metals Subcategory. 

2.	 If EPA sampled the same unit operation bath (or rinse) at facilities in only 

one MP&M subcategory, even if it is a different subcategory than that of 

the model site, the Agency transferred these data to the same unit 

12-8

12.0 - Pollutant Loading and Reduction Estimates 

operation bath (or rinse) at model sites. For example, if available 

analytical data for a unit operation exist only for the General Metals 

Subcategory, EPA transferred these data to model the wastewater pollutant 

concentrations for the same unit operation at a model site in any other 

subcategory. 

3.	 If EPA did not have unit operation sampling data from a site in 

Subcategory A, then EPA used unit operation sampling data from a site in 

a similar subcategory (e.g., if Subcategory A is a metal-bearing 

subcategory, data from another metal-bearing subcategory was used). The 

Agency used available analytical data for the same operation in similar 

subcategories to estimate wastewater pollutant concentrations for the 

model site unit operation. For example, if available analytical data for a 

unit operation bath (or rinse) exist from both metal-bearing wastewater 

facilities and oil-bearing wastewater facilities, EPA used the following 

approach. If the model site is designated as one of the metal-bearing 

wastewater subcategories, only available analytical data from other 

metal-bearing wastewater subcategorized facilities were used to estimate 

wastewater pollutant concentrations. EPA used the same approach for 

oil-bearing wastewater subcategories. 

4.	 If EPA did not sample a unit operation bath (or rinse) that is the same as 

the unit operation at a model site, the Agency used the available analytical 

data for a unit operation bath (or rinse) that has similar wastewater 

characteristics, but are within the same subcategory, to estimate 

wastewater pollutant concentrations for the model site unit operation. Due 

to budget constraints, EPA did not collect data for 22 baths and 24 rinses, 

representing approximately 8.3 percent of the total MP&M discharge flow 

rate. The basis for these estimates are discussed in the memorandum 

entitled “Data Transfers Between Unit Operations” located in the 

rulemaking record (Section 16.7, DCN 17767). 

Supporting documentation for all data transfers of unit operation pollutant 

concentrations is contained in Section 16.7 of the MP&M rulemaking record. 

12.2 Estimation of Industry Baseline Pollutant Loadings 

Industry baseline wastewater pollutant loadings are modeled pollutant loadings in 

MP&M wastewater discharged to surface waters or to POTWs for the base year of the detailed 

surveys, supplemented by additional site information provided to EPA. These loadings reflect 

wastewater treatment in place at model sites in the year 1996. EPA estimated baseline pollutant 

loadings using the effluent pollutant concentrations, unit operation flows provided in the 

questionnaire (as described in Section 11.2.2), and effluent flows from treatment (estimated by 

the EPA Costs & Loadings Model as described in Section 11.3.3). EPA estimated the baseline 

pollutant loadings using the approaches described in this subsection. 

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12.0 - Pollutant Loading and Reduction Estimates 

12.2.1
 Estimation of Baseline Pollutant Concentrations from Sites in the MetalBearing Subcategories 

For the final rule, EPA revised its methodology for estimating baseline pollutant 

concentrations in metal-bearing subcategories. The final methodology varies depending on 

whether or not the stream is treated or untreated and also by its current regulatory status. 

12.2.1.1 Estimation of Effluent Pollutant Concentrations for Untreated Streams 

EPA used the following steps to estimate the wastewater pollutant concentrations 

for each pollutant of concern (POC) in wastewater discharged from model sites without 

treatment: 

1.	 Estimated wastewater pollutant concentrations for each unit operation

that discharges wastewater from the site without treatment. EPA 

estimated unit operation wastewater pollutant concentrations using the 

methodology described in Section 12.1. EPA notes that the unit 

operations data were significantly revised between the proposal and the 

Notice of Data Availability (NODA), and have been revised further based 

on comments on the NODA (see DCN 16764 in Section 16.7 of the 

rulemaking record). 

2.	 Incorporated limits on wastewater discharged from sites regulated by 40

CFR 413 only (Baseline for the 413 to 433 Upgrade Analysis). For the 

final rule, in response to comments, EPA accounted for sites that are 

currently regulated by and complying with Part 413. For streams not 

currently receiving treatment at model sites subject to Part 413, but not 

Part 433, EPA assumed the sites achieved the monthly average limitation 

for Part 413 regulated parameters (i.e., set the wastewater pollutant 

concentrations equal to the Part 413 limits (as opposed to achieving the 

long-term average (LTA) concentration)). EPA noted that the Part 413 

limit for cyanide is different for small platers than for large platers. For 

parameters not regulated by Part 413, EPA estimated wastewater pollutant 

concentrations from the unit operations data. MP&M facilities covered 

under Part 413 only include some, but not all, indirect dischargers in the 

Printed Wiring Board, Metal Finishing Job Shops, and General Metals 

Subcategories. EPA conducted a unique analysis to determine the costs 

and loads associated with the upgrade of facilities regulated under Part 413 

to meet the Part 433 limits. EPA used the methodology described in this 

section to estimate baseline pollutant concentrations of untreated streams 

for this analysis. 

3.	 Incorporated limits on wastewater discharged from sites regulated by 40

CFR 433 (or Parts 413 and 433). For the final rule, in response to 

comments, EPA accounted for sites that are currently regulated by and 

12-10

12.0 - Pollutant Loading and Reduction Estimates 

complying with 40 CFR 413 and 433, or 433 only. EPA assumed the 

untreated streams achieved the monthly average limitation for Part 433 

regulated parameters (i.e., set the wastewater pollutant concentrations 

equal to the Part 433 limits (as opposed to achieving the LTA 

concentration)). For parameters not regulated by Part 433, EPA estimated 

wastewater pollutant concentrations from the unit operations data. MP&M 

facilities covered under Part 433 include all direct and some indirect 

dischargers in the Printed Wiring Board and Metal Finishing Job Shops 

Subcategories, and some direct and indirect dischargers in the General 

Metals and Non-Chromium Anodizing Subcategories. 

4.	 Incorporated limits on wastewater discharged from sites not regulated by

40 CFR 413 or 433 (Baseline for the Local Limits to 433 Upgrade

Analysis). For the final rule, in response to comments, EPA also 

incorporated changes to take into account the compliance of indirect 

dischargers in the General Metals Subcategory, not currently regulated by 

Parts 413 or 433, with local limits. Although EPA could not obtain actual 

local limits for all facilities, EPA gathered local limits data from 213 

POTWs in seven EPA Regions to develop national median local limit 

values. (see DCN 17844 of the rulemaking record for a list of the data and 

the median value for each parameter). EPA assumed the untreated streams 

achieved the national median local limit for all parameters regulated by 

Part 433 in untreated streams. For parameters not regulated by Part 433, 

EPA estimated wastewater pollutant concentrations from the unit 

operations data. EPA conducted a unique analysis to determine the costs 

and loads associated with the upgrade of facilities not regulated under 

Parts 413 or 433 to meet the Part 433 limits. EPA used the methodology 

described in this section to estimate baseline pollutant concentrations of 

untreated streams for this analysis. 

5.	 Estimated commingled wastewater concentrations for all untreated

streams. EPA combined the wastewater from all unit operation discharges 

that are not sent through treatment. EPA calculated the commingled 

concentration of each POC in the combined MP&M wastewater based on 

pollutant concentrations and flow rates of each stream. 

12.2.1.2 Estimation of Effluent Pollutant Concentrations for Treated Streams 

EPA used the Costs & Loadings Model (see Section 11.0) to estimate the 

pollutant concentrations in wastewater discharged from the treatment technology at each model 

site. EPA used the following steps to estimate the wastewater pollutant concentrations for each 

POC in treated discharged wastewater: 

1. 	 Estimated wastewater pollutant concentrations for each unit operation

that discharges wastewater to treatment. EPA estimated unit operation 

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12.0 - Pollutant Loading and Reduction Estimates 

wastewater pollutant concentrations using the methodology described in 

Section 12.1. EPA notes that the unit operations data were significantly 

revised between the proposal and the NODA, and have been revised 

further based on comments on the NODA (see DCN 16764 in Section 16.7 

of the rulemaking record). 

2.	 Estimated wastewater concentrations in influent to treatment (commingled

wastewater concentrations for all treated streams). EPA combined the 

wastewater from all unit operations that discharge to treatment. EPA 

calculated the commingled (treatment influent) concentration of each POC 

in the combined MP&M wastewater, based on pollutant concentrations 

and flow rates of each stream. The treatment influent concentrations are 

required to estimate baseline costs (see Section 11.0). 

3.	 Estimated wastewater concentrations in effluent from treatment. EPA 

used the Costs & Loadings Model (see Section 11.0) to estimate the 

pollutant concentrations in wastewater discharged from each model site 

wastewater treatment unit. The following summarizes the pollutant 

concentrations for the various treatment technologies reported for the 

metal-bearing subcategories. 

�

Treatment Equivalent to the Metal Finishing (40 CFR 433) Best

Available Treatment (BAT). EPA assumed that all streams that 

undergo treatment equivalent2 to the Metal Finishing (40 CFR 433) 

BAT technology basis are treated to achieve the LTAs promulgated 

at 40 CFR 433 for those parameters regulated under Part 433 (433 

parameters). EPA assumed that parameters not regulated under 

Part 433 (non-433 parameters) are treated to achieve the LTAs 

based on MP&M BAT (Option 2) sampled sites. 

�

Microfiltration for Solids Removal Technology. For streams 

treated by a membrane system, EPA assumed that the membrane 

technology could treat to a lower concentration than the 433 LTAs. 

Therefore, EPA assumed the membrane technology could achieve 

the lower of the LTAs calculated based on MP&M sampled sites 

using membrane technology or the 433 LTAs. 

�

Chemical Reduction of Chelated Metals. For streams treated by a 

chelation breaking system, EPA assumed the reduction of chelated 

metals to the elemental state. The concentrations of carbon 

disulfide and dithiocarbamate (DTC) increase in the chelation 

breaking module to account for addition of treatment chemicals. 

2

Refer to Table 11-5 for treatment technologies considered equivalent to chemical precipitation and sedimentation. 

12-12 
12.0 - Pollutant Loading and Reduction Estimates 

�

Oil Treatment (Chemical Emulsion Breaking and Oil/Water

Separation) and Batch Oil Emulsion Breaking with Gravity

Flotation. EPA assumed oil treatment and batch oil emulsion 

breaking technologies could achieve the LTAs calculated based on 

MP&M sampled sites using chemical emulsion breaking with 

gravity oil/water separation. 

�

Ultrafiltration (for Oil Removal). EPA assumed ultrafiltration 

technologies could achieve the LTAs calculated based on MP&M 

sampled sites using ultrafiltration (for oil removal). 

�

Dissolved Air Flotation (DAF). EPA assumed DAF technology 

could achieve the 433 limits for all 433 parameters. For non-433 

parameters, EPA assumed DAF technology could achieve the 

LTAs calculated based on MP&M sampled sites using DAF 

technology. 

�

Cyanide Destruction and Ion Exchange. EPA assumed cyanide 

destruction and ion exchange technologies could reduce the 

amount of cyanide in cyanide-bearing wastewater. EPA assumed 

total cyanide, amenable cyanide, and weak-acid dissociable 

cyanide are reduced to the LTAs calculated based on MP&M 

sampled sites using cyanide destruction. The concentration of 

chloroform increases in the cyanide destruction module to account 

for the reduction process. 

�

Chemical Reduction of Hexavalent Chromium. EPA assumed 

hexavalent chromium reduction could reduce the amount of 

hexavalent chromium to achieve the LTA calculated based on 

MP&M sampled sites using hexavalent chromium reduction. The 

concentration of trivalent chromium increases in the hexavalent 

chromium reduction module to account for the conversion process. 

Note that if the treated effluent concentration for a pollutant was more than 

its corresponding treatment influent concentration (obtained in step 2 

above), EPA retained the treatment influent concentration to estimate the 

baseline concentration for that pollutant. 

4.	 Incorporated limits on wastewater discharged from sites regulated by 40

CFR 413 only (Baseline for the 413 to 433 Upgrade Analysis). For the 

final rule, in response to comments, EPA accounted for sites that are 

currently regulated by and complying with Part 413 only. For streams 

receiving treatment at model sites subject to Part 413, but not Part 433, 

EPA assumed the sites achieved the LTAs for Part 413 regulated 

parameters (i.e., set the wastewater pollutant concentrations equal to the 

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12.0 - Pollutant Loading and Reduction Estimates 

Part 413 LTA concentration). EPA noted that 40 CFR 413 only sets 

limitations on lead, cadmium, and cyanide for small platers. EPA assumed 

small platers achieved the monthly limit average for those additional 

parameters regulated by Part 413 for large platers. For parameters not 

regulated by Part 413, EPA assumed sites achieve the baseline pollutant 

concentrations for the treatment technology. MP&M facilities covered 

under Part 413 only include some indirect dischargers in the Printed 

Wiring Board, Metal Finishing Job Shops, and General Metals 

Subcategories. EPA conducted a unique analysis to determine the costs 

and loads associated with the upgrade of facilities regulated under Part 413 

to meet the Part 433 limits. EPA used the methodology described in this 

section to estimate baseline pollutant concentrations of treated streams for 

this analysis. 

5.	 Incorporated limits on wastewater discharged from sites not regulated by

40 CFR 413 or 433 (Baseline for the Local Limits to 433 Upgrade

Analysis). For the final rule, in response to comments, EPA also 

incorporated changes to take into account the compliance of indirect 

dischargers in the General Metals Subcategory, not currently regulated by 

Parts 413 or 433, with local limits. Although EPA could not obtain actual 

local limits for all facilities, EPA gathered local limits data from 213 

POTWs in seven EPA Regions to develop national median local limit 

values. (see DCN 17844 of the rulemaking record for a list of the data and 

the median value for each parameter). EPA assumed the treated streams 

achieved one-half of the national median local limit values

3

 for all 

parameters regulated by Part 433. For parameters not regulated by Part 

433, EPA assumed the treated streams achieved the national median local 

limit values. EPA conducted a unique analysis to determine the costs and 

loads associated with the upgrade of facilities not regulated under Parts 

413 or 433 to meet the Part 433 limits. EPA used the methodology 

described in this section to estimate baseline pollutant concentrations of 

treated streams for this analysis. 

12.2.1.3 Estimation of Commingled Effluent Pollutant Concentrations from Sites 

EPA combined the wastewater from treated and untreated streams. EPA 

calculated the commingled baseline effluent pollutant concentration of each POC in the 

combined MP&M wastewater based on pollutant concentrations and flow rates of each stream 

(treated and untreated). 

EPA received comments that, although the concentration of chemical oxygen 

demand (COD) in discharged wastewater is not regulated by Parts 413 or 433 (unlike oil and 

3

EPA used 1⁄2 the median value to take into account that facilities do not operate treatment systems to achieve the 

limit, but some value below the limit to account for variability. 

12-14 
12.0 - Pollutant Loading and Reduction Estimates 

grease and total suspended solids), it is typically regulated by local limits. EPA reviewed data 

from the Permit Compliance System (PCS) and found that, while COD is not generally regulated 

by local limitations, a small number of facilities do have COD restrictions. EPA found similar 

results for total kjeldahl nitrogen (TKN) and ammonia as nitrogen (NH)4. Since EPA could not 

identify which sites in PCS may have been subject to MP&M, EPA conducted its analysis using 

information from process wastewater dischargers from facilities in the 3000 series SIC codes. 

Using information from those sites with COD, TKN, and NH limitations, EPA calculated a 

single local limit value for each parameter. These values are 175, 35.67, and 19.3 mg/L for 

COD, TKN, and NH, respectively. EPA compared the baseline pollutant concentrations it 

predicted for these pollutants at each site. If these concentrations were in excess of the local 

limit value, then EPA set the concentration for the commingled MP&M wastewater discharged 

from each model site in metal-bearing wastewater subcategories equal to the local limit value. 

Details are provided in the memorandum “Loadings Methodology for Cost Model Run 4” (DCN 

17846 in Section 24.7 of the rulemaking record). 

12.2.2 Estimation of Baseline Pollutant Concentrations from Sites in the OilBearing Subcategories 

For the proposal and the NODA, EPA’s methodology to estimate baseline 

pollutant concentrations for facilities in oil-bearing wastewater subcategories was similar to the 

one used at that time for metal-bearing wastewater subcategories. EPA received comment on the 

proposal and NODA that this methodology overestimated baseline pollutant concentrations for 

Shipbuilding Dry Dock, Railroad Line Maintenance, and Oily Waste sites. In response to these 

comments, EPA significantly revised its methodology for estimating baseline pollutant 

concentrations in the oil-bearing wastewater subcategories. Because EPA has different types of 

information in its database for each oil-bearing wastewater subcategory, it used different methods 

to represent baseline pollutant concentrations for each oil-bearing wastewater subcategory. The 

final methodologies used for each oil-bearing wastewater subcategory are described individually 

below. 

12.2.2.1 Estimation of Baseline Pollutant Concentrations from Sites in the 

Shipbuilding Dry Dock Subcategory 

For the final rule, EPA used its sampling data and industry supplied long-term 

monitoring data to estimate baseline pollutant concentrations for this subcategory. This data 

includes pollutant concentrations measured at two EPA sampling episodes and those reported in 

three years of Detailed Monitoring Reports (DMR) covering numerous dry dock discharges from 

a single shipbuilding dry dock facility. In estimating baseline pollutant concentrations in this 

manner, EPA looked at the individual data points as well as averages for its conclusions. See 

DCNs 17859 and 17860 in Sections 24.6.1 and 24.5.1 of the final rulemaking record for 

additional information. Note that for the final rule, EPA only estimated baseline concentrations 

for total suspended solids (TSS) and oil and grease because EPA had previously determined that 

4

EPA reviewed these parameters because they were important in estimating benefits (see the Economic, 

Environmental, and Benefits Analysis for the Final MP&M Rule (EEBA)). 

12-15 
12.0 - Pollutant Loading and Reduction Estimates 

discharges from these facilities contain minimal concentrations of toxic organic and metal 

pollutants. 

12.2.2.2 Estimation of Baseline Pollutant Concentrations from Sites in the Railroad 

Line Maintenance Subcategory 

In response to proposal and NODA comments, EPA revisited its database of 

direct discharging Railroad Line Maintenance facilities. EPA found that many of the facilities in 

its database would not be subject to this rule because they discharged only noncontaminated 

stormwater or wastewater resulting from refueling operations (neither of which is subject to the 

final rule). As a result of this review, EPA concluded its database was insufficient to make any 

regulatory decisions on direct discharging Railroad Line Maintenance facilities. 

However, as part of its comments on the proposed rule and as discussed more 

fully in the NODA (67 FR 38755), the American Association of Railroads (AAR) provided a 

census listing of each Railroad Line Maintenance direct discharging facility known to them. For 

each facility, AAR provided a description of treatment technologies, a summary of effluent data, 

including flow rates, permit limits, and a process flow diagram or description of the operations. 

For the final rule, EPA used this information to create a new database representing direct 

discharging Railroad Line Maintenance facilities. 

EPA’s final database consists of nine direct discharging Railroad Line 

Maintenance facilities. Six of the nine facilities use technologies consistent with the Option 6 

technology basis, two use technologies consistent with the Option 10 technology basis, and one 

uses biological treatment. 

For the final rule, EPA did not need to model effluent pollutant concentrations for 

each of the final database facilities. Rather, EPA used the summary effluent data provided for 

each facility to represent baseline oil and grease and TSS concentrations in the Railroad Line 

Maintenance Subcategory. For additional information, see DCN 17861 in Section 24.6.1 of the 

rulemaking record. Note that EPA considered only TSS and oil and grease because it had 

previously determined that discharges in this subcategory contain few pounds of toxic pollutants. 

12.2.2.3 Estimation of Baseline Pollutant Concentrations from Sites in the Oily 

Wastes Subcategory 

For the final rule, EPA estimated baseline pollutant concentrations using a 

different methodology for treated and untreated streams in the oily waste subcategory. 

Treated Streams:	 Where EPA had survey information (DMR data) for a particular site with 

treatment, EPA used that information as the baseline pollutant 

concentration. For half of the oily waste subcategory facilities with 

treatment, however, EPA had to estimate baseline pollutant 

concentrations. In all of these cases, EPA determined the treatment 

currently in place would achieve equivalent or greater removals to the 

12-16

12.0 - Pollutant Loading and Reduction Estimates 

treatment technology considered as the technology basis for limitations in 

this subcategory (Option 6). Therefore, where EPA did not have DMR 

data for a facility with treatment in place, EPA estimated its baseline 

pollutant concentrations as the median effluent concentrations of the DMR 

data from facilities with the option 6 technology. 

Untreated Streams:	 EPA had DMR data for one site that indicated no treatment. Therefore, 

EPA used this data as the baseline pollutant concentrations for this facility. 

For the remaining sites without treatment, EPA had to estimate baseline 

pollutant concentrations. For these sites, EPA estimated unit operation 

wastewater pollutant concentrations using the methodology described in 

Section 12.1. EPA notes that it significantly revised the unit operations 

data between the proposal and the NODA, and between the NODA and 

final rule based on comments on the NODA (see DCN 16764, in Section 

16.7 of the rulemaking record). EPA combined the wastewater from all 

unit operation discharges that are not sent through treatment. EPA 

calculated the commingled concentration of each POC in the combined 

MP&M wastewater based on pollutant concentrations and flow rates of 

each stream. 

12.2.3 Estimation of Model Site Baseline Loadings 

EPA estimated the pollutant loadings (lbs/yr) in effluent wastewater (treated or 

untreated) discharged from each MP&M model site. EPA estimated pollutant-specific baseline 

loadings by multiplying the effluent pollutant concentration of the pollutant by the corresponding 

effluent wastewater flow rate. To determine site-specific pollutant baseline loadings for sites that 

have both treated and untreated streams, EPA summed the estimated pollutant-specific baseline 

loading from the untreated effluent and the treated effluent. EPA estimated site-specific baseline 

loadings by summing site-specific pollutant baseline loadings for all pollutants considered. 

For direct dischargers in the General Metals Subcategory, EPA additionally 

compared the baseline pollutant loadings from EPA’s Costs & Loadings Model to available 

DMR data. EPA obtained DMR data for 18 of the model sites. The MP&M model did not 

overestimate baseline loadings for 12 of these 18 model direct discharging facilities (or 

approximately two-thirds of these facilities). The relative percent difference (in poundequivalents) of the model baseline loadings and those estimated using DMR data is 14 percent. 

Based on this analysis, EPA concluded that the MP&M model estimates of baseline pollutant 

loadings are reasonable and appropriate. 

12.2.4 Estimation of Industry-Wide Baseline Pollutant Loadings 

EPA multiplied the site-specific baseline wastewater loadings by the 

corresponding statistically derived weighting factors (see Section 3.0) for each model site. EPA 

summed the weighted loadings across all sites in each subcategory to estimate 

subcategory-specific baseline wastewater pollutant loadings. EPA also summed the weighted 

12-17

12.0 - Pollutant Loading and Reduction Estimates 

loadings across all sites to estimate industry-wide baseline wastewater pollutant loadings. Table 

12-2 presents the estimated baseline pollutant loadings by subcategory for direct and indirect 

dischargers. 

12.3 Estimation of Industry Option Pollutant Loadings 

Industry option pollutant loadings (i.e., post-compliance pollutant loadings for the 

technology option) represent the total loadings of pollutants in all MP&M wastewater that would 

be discharged to surface waters or POTWs after complying with the regulatory option. The 

estimation of industry option pollutant loadings for each subcategory is described in the 

following subsections. 

12.3.1 Estimation of Industry Option Pollutant Loadings for Sites in the MetalBearing Subcategories 

Direct Dischargers (General Metals Subcategory). EPA estimated option effluent 

concentrations assuming that all direct discharging MP&M facilities in the General Metals 

Subcategory would achieve long-term average effluent pollutant concentrations associated with 

the MP&M sampled sites performing BAT (Option 2, including chemical precipitation with 

clarification). EPA estimated effluent concentrations for all pollutants of concern (listed in 

Section 7.0). Note that if the long-term average effluent concentration for a pollutant was more 

than its corresponding treatment influent concentration (based on unit operation wastewater 

concentrations), EPA retained the treatment influent concentration to estimate the option effluent 

concentration for that pollutant. 

Indirect Dischargers - 413 to 433 Upgrade Analysis for sites regulated by 40 

CFR 413 only (General Metals, Printed Wiring Board, and Metal Finishing Job Shop 

Subcategories). EPA estimated option effluent concentrations assuming all indirect discharging 

MP&M facilities in metal-bearing subcategories, currently regulated by 40 CFR 413 only, would 

achieve long-term average effluent pollutant concentrations associated with the BAT sites 

sampled under development of 40 CFR 433 (at the option). EPA estimated effluent 

concentrations only for pollutants regulated under 40 CFR 433. 

Indirect Dischargers - Local Limits to 433 Upgrade Analysis for sites regulated 

by local limits (General Metals Subcategory). EPA estimated option effluent concentrations 

assuming all indirect discharging facilities in the General Metals Subcategory, not currently 

regulated by 40 CFR 413 or 433, would achieve long-term average effluent pollutant 

concentrations associated with the BAT sites sampled under development of 40 CFR 433 (at the 

option). For pollutants regulated under local limits, but not regulated under Part 433, EPA 

assumed the facilities would achieve the national median local limit values. EPA estimated 

effluent concentrations only for pollutants regulated under local limits. 

EPA then estimated post-compliance pollutant loadings for each model facility by 

multiplying the treated effluent concentration by its wastewater flow rate to obtain a mass 

loading (in pounds) for each pollutant. Finally, EPA estimated site-specific option loadings. 

12-18

12.0 - Pollutant Loading and Reduction Estimates 

EPA summed the mass loadings for all pollutants in the final effluent discharged from the model 

site. 

12.3.2 Estimation of Industry Option Pollutant Loadings for Sites in the 

Shipbuilding Dry Dock Subcategory 

Because EPA concluded that national regulation of discharges from the 

Shipbuilding Dry Dock Subcategory is unwarranted5

, EPA did not assess option pollutant 

loadings for this subcategory. 

12.3.3 Estimation of Industry Option Pollutant Loadings for Sites in the Railroad 

Line Maintenance Subcategory 

For this subcategory, EPA used information in its database on current permit 

limitations for facilities operating the Option 6 technology to estimate post-compliance pollutant 

loadings. All of the facilities that operate the Option 6 technology have a daily maximum oil and 

grease limit of 15 mg/L. For TSS, half of the facilities have a daily maximum limit of 45 mg/L 

while the other half have no limit. Based on this information, the oil and grease and TSS daily 

maximum limits representing the average of the best performing Option 6 facilities would be 15 

mg/L and 45 mg/L, respectively. To estimate pollutant loadings for each model facility, EPA 

multiplied these maximum limits by the wastewater flow (provided in the survey) to obtain a 

mass loading (in pounds) for TSS. 

12.3.4 Estimation of Industry Option Pollutant Loadings for Sites in the Oily 

Wastes Subcategory 

EPA calculated the loadings assuming that all Oily Wastes sites would achieve 

long-term average effluent pollutant concentrations associated with the MP&M sampled sites 

performing BAT (Option 6, including chemical emulsion breaking with gravity oil/water 

separation). 

First, EPA estimated the pollutant concentrations in the effluent from treatment at 

each model site, using the LTAs calculated from MP&M BAT sampled sites. The calculated 

LTAs for oil and grease and TSS are 18.89 mg/L and 44 mg/L, respectively. Note that if the 

long-term average effluent concentration for a pollutant was more than its corresponding 

treatment influent concentration (based on unit operation wastewater concentrations), EPA 

retained the treatment influent concentration to estimate the option concentration for that 

pollutant. 

Second, EPA estimated site-specific pollutant loadings. EPA multiplied the 

pollutant concentrations in the final effluent (discharged from the model site) by the wastewater 

5

See Section VI.H of the final preamble for additional discussion. 

12-19 
12.0 - Pollutant Loading and Reduction Estimates 

flow rate (calculated in the EPA Costs & Loadings Model, or provided in the DMR) to obtain a 

mass loading (in pounds) for each pollutant. 

Finally, EPA estimated site-specific option loadings. EPA summed the mass 

loadings for all pollutants in the final effluent discharged from the model site. 

12.4 Estimation of Pollutant Reductions 

Option pollutant reductions represent the incremental amount of pollutants 

removed by each technology option with respect to EPA’s estimated baseline pollutant loadings. 

EPA estimated baseline pollutant loadings as explained in Section 12.2. EPA estimated option 

pollutant loadings as explained in Section 12.3. EPA estimated pollutant reductions as follows: 

1.	 Estimated site-specific, pollutant-specific option removals. EPA 

calculated the difference between the model site’s baseline pollutant 

loadings and option pollutant loadings. For direct dischargers, EPA 

considered all pollutants of concern, with the exception of boron, sodium, 

calcium, and total dissolved solids. For indirect dischargers, EPA 

considered only pollutants regulated under 40 CFR 433. EPA further 

reduced the model site’s option-specific pollutant removals for indirect 

dischargers by their corresponding POTW percent removal (listed in Table 

12-1) to account for treatment that will occur at the POTW. A detailed 

discussion of how EPA developed pollutant-specific POTW percent 

removals is provided in Section 7.3.1 of the Technical Development 

Document for the Proposed Effluent Limitations Guidelines and Standards 

for the Metal Products and Machinery Point Source Category. 

2.	 Modified site-specific, pollutant-specific option removals. First, if the 

option-specific concentration for certain pollutant(s) was greater than the 

estimated baseline concentration for a model site, EPA set option-specific 

loadings for the pollutant(s) equal to the baseline loadings at those sites 

(EPA set the option-specific pollutant removal for that model site equal to 

zero). This was the case if the pollutant long-term average concentration 

for the treatment currently in place at the site was lower than that for 

EPA’s treatment technology option (i.e., a model facility uses membrane 

technology, but EPA’s option technology is chemical precipitation). 

Second, EPA set all removals of boron equal to zero. EPA determined 

that boron is not removed by most of the selected option treatment 

technologies, as discussed in the NODA. For additional details, refer to 

the memorandum entitled “Treatment System Removal of Boron from 

MP&M Wastewaters” in Section 16.7, DCN 16758 of the rulemaking 

record. 

3.	 Estimated toxic site-specific, pollutant-specific option removals. EPA also 

calculated the site-specific, pollutant specific removals in toxic 

12-20

12.0 - Pollutant Loading and Reduction Estimates 

pound-equivalents. A pound-equivalent (PE) is a pound of pollutant 

weighted for its toxicity to human and aquatic life. EPA multiplied the 

site-specific option pollutant removals (in pounds) by the corresponding 

toxic-weighting factor (TWF). 

4.	 Estimated site-specific option removals. EPA summed the pollutant 

removals for all pollutants at the model site. 

5.	 Estimated industry-wide option loadings and removals. For each option, 

EPA multiplied the site-specific option loadings and removals (accounting 

for POTW removals for indirect dischargers) by the corresponding 

statistically derived weighting factors for each model site. EPA summed 

the weighted loadings and removals across all sites in each subcategory to 

estimate subcategory-specific option loadings and removals for each 

option. EPA also summed the weighted loadings and removals across all 

sites to estimate industry-wide option loadings and removals. 

Table 12-3 presents the estimated selected option pollutant loadings by 

subcategory for direct and indirect dischargers. Tables 12-4 and 12-5 present the estimated 

pollutant removals by the selected option in pounds (for direct dischargers only) and poundequivalents (for both direct and indirect dischargers), respectively. 

Note that, for the final rule, EPA did not provide option pollutant loadings or 

reductions for the Shipbuilding Dry Dock or Railroad Line Maintenance Subcategories. EPA 

concluded that pollutant removals associated with national regulation of these subcategories 

would be negligible. See DCNs 17859 and 17861 in Section 24.6.1 of the rulemaking record for 

more detailed discussion of the Shipbuilding Dry Dock and Railroad Line Maintenance 

Subcategories, respectively. 

12-21

12.0 - Pollutant Loading and Reduction Estimates 

Table 12-1	

POTW Removal Percentages For Each MP&M Pollutant of Concern 	

Chemical Name POTW Percent Removal Source 

1,1,1-Trichloroethane 90.45 a 

1,1-Dichloroethane 70 a 

1,1-Dichloroethene 77.51 c 

1,4-Dioxane 45.8 b 

1-Bromo-2-Chlorobenzene 77.32 c 

1-Bromo-3-Chlorobenzene 77.32 c 

1-Methylfluorene 84.55 b 

1-Methylphenanthrene 84.55 b 

2,4-Dimethylphenol 77.51 c 

2,4-Dinitrophenol 77.51 c 

2,6-Dinitrotoluene 77.51 c 

2-Butanone 96.6 b 

2-Hexanone 77.32 c 

2-Isopropylnaphthalene 77.32 c 

2-Methylnaphthalene 28 b 

2-Nitrophenol 26.83 a 

2-Propanone 83.75 b 

3,6-Dimethylphenanthrene 84.55 b 

4-Chloro-3-Methylphenol 63 b 

4-Methyl-2-Pentanone 87.87 b 

4-Nitrophenol 77.51 c 

Acenaphthene 98.29 a 

Acetophenone 95.34 b 

Acrolein 77.51 c 

Alpha-Terpineol 94.4 b 

Aluminum 91.36 a 

Amenable Cyanide 57.41 c 

Ammonia As Nitrogen 38.94 a 

Aniline 93.41 b 

Anthracene 77.51 c 

Antimony 66.78 a 

Arsenic 65.77 a 

Barium 15.98 a 

Benzoic Acid 80.5 b 

Benzyl Alcohol 78 b 

12-22

12.0 - Pollutant Loading and Reduction Estimates 

Table 12-1 (Continued) 

Chemical Name POTW Percent Removal Source 

Beryllium 71.66 c 

Biphenyl 96.28 b 

Bis(2-Ethylhexyl) Phthalate 59.78 a 

BOD 5-Day (Carbonaceous) 89.12 a 

Boron 30.42 a 

Butyl Benzyl Phthalate 81.65 a 

Cadmium 90.05 a 

Calcium 8.54 a 

Carbon Disulfide 84 b 

Chemical Oxygen Demand (COD) 81.3 a 

Chloride 57.41 c 

Chlorobenzene 96.37 a 

Chloroethane 77.51 c 

Chloroform 73.44 a 

Chromium 80.33 a 

Cobalt 6.11 a 

Copper 84.2 a 

Cyanide 70.44 a 

Di-N-Butyl Phthalate 84.66 a 

Di-N-Octyl Phthalate 68.43 a 

Dibenzofuran 77.32 c 

Dibenzothiophene 84.68 b 

Dimethyl Phthalate 77.51 c 

Diphenyl Ether 77.32 c 

Diphenylamine 77.32 c 

Ethylbenzene 93.79 a 

Fluoranthene 42.46 a 

Fluorene 69.85 a 

Fluoride 61.35 

Gold 32.52 c 

Hexanoic Acid 84 b 

Hexavalent Chromium 57.41 c 

Iron 81.99 a 

Isobutyl Alcohol 28 b 

Isophorone 77.51 c 

Lead 77.45 a 

m+p Xylene 77.32 c 

12-23

12.0 - Pollutant Loading and Reduction Estimates 

Table 12-1 (Continued) 

Chemical Name POTW Percent Removal Source 

m-Xylene 95.07 b 

Magnesium 14.14 a 

Manganese 35.51 a 

Mercury 71.66 c 

Methyl Methacrylate 99.96 b 

Methylene Chloride 54.28 a 

Molybdenum 18.93 a 

n,n-Dimethylformamide 87 b 

n-Decane 9 b 

n-Docosane 88 b 

n-Dodecane 95.05 b 

n-Eicosane 92.4 b 

n-Hexacosane 71.11 b 

n-Hexadecane 71.11 b 

n-Nitrosodimethylamine 77.51 c 

n-Nitrosodiphenylamine 90.11 b 

n-Nitrosopiperidine 77.32 c 

n-Octacosane 71.11 b 

n-Octadecane 71.11 b 

n-Tetracosane 71.11 b 

n-Tetradecane 71.11 b 

n-Triacontane 77.32 c 

Naphthalene 94.69 a 

Nickel 51.44 a 

o+p Xylene 65.4 b 

o-Cresol 52.5 b 

o-Xylene 77.32 c 

Oil and Grease (as HEM) 86.08 a 

p-Cresol 71.67 b 

p-Cymene 99.79 b 

Phenanthrene 94.89 a 

Phenol 95.25 a 

Phosphorus 32.52 c 

Pyrene 83.9 b 

Pyridine 95.4 b 

Selenium 34.33 b 

Silver 88.28 a 

12-24

12.0 - Pollutant Loading and Reduction Estimates 

Table 12-1 (Continued) 

Chemical Name POTW Percent Removal Source 

Sodium 2.69 a 

Styrene 93.65 b 

Sulfate 84.61 b 

Tetrachloroethene 84.61 a 

Thallium 71.66 c 

Tin 42 a 

Titanium 91.82 a 

Toluene 96.18 a 

Total Dissolved Solids 8 b 

Total Kjeldahl Nitrogen 57.41 c 

Total Organic Carbon (TOC) 70.28 a 

Total Petroleum Hydrocarbons (as SGT-HEM) 57.41 c 

Total Phosphorus 57.41 c 

Total Recoverable Phenolics 57.41 c 

Total Sulfide 57.41 c 

Total Suspended Solids 89.55 a 

Trichloroethene 77.51 c 

Trichlorofluoromethane 77.32 c 

Tripropyleneglycol Methyl Ether 52.4 b 

Vanadium 9.51 a 

Weak-Acid Dissociable Cyanide 57.41 c 

Yttrium 32.52 c 

Zinc 79.14 a 

Note: See the rulemaking record for further detail for the sources. 


a - November 5, 1999 Updated 50-POTW Study. Influent Concentration 10xML, 5xML, then 20 ppb.


b - RREL Database. Compiled for the CWT effluent guideline or the 1995 Phase I Proposal.


c - Average POTW removals calculated by classification code from sources a and b. 


12-25

12.0 - Pollutant L

Table 12-2	

Summary of Baseline Annual Pollutant Loadings Discharged by Subcatego

12-26


Subcategory 

Discharge 

Status 

Options Evaluated 

Since Proposal 

NODA Fin

Number of 

Sites 

Pound 

Equivalents 

(PE/yr)b 

Pounds (lbs/yr) 

Number 

of Sites 

Pound 

Equivalents 

(PE/yr)b 

Totalb 

TSS/Oil 

and Grease 

(as HEM) 

General Metals Direct Option 2 1,521 2,009,351 174,459,398 7,322,917 228 270,336 

Indirect Option 2, 1 MGY 

cutoff 

2,354 6,234,209 1,106,541,984 41,557,113 

Upgrade Option NA 429 391,340 

50% Local Limits NA 628 236,171 

Metal Finishing Job 

Shops 

Direct Option 2 24 3,358 950,820 21,111 

Indirect Option 2 1,270 438,866 63,845,074 2,002,275 

Upgrade Option NA 314 82,633 

Non-Chromium 

Anodizing 

Directc Option 2 

(model site) 

35 2,405,434 219,633,506 4,665,748 19 3,924 

Indirect Not Proposed NA 

Printed Wiring Board Direct Option 2 4 527 70,681 1,584 

Indirect Option 2 840 923,431 82,596,963 4,040,990 

Upgrade Option NA 354 73,624 

Steel Forming and 

Finishing 

Direct Option 2 

Not Covered by MP&M 

Indirect Option 2 

Oily Wastes Direct Option 6 2,749 11,149 30,585,116 5,709,823 2,382 3,351 

Indirect Option 6, 2 MGY 

cutoff 

288 78,247 189,374,738 46,336,329 
12.0 - Pollutant L

Table 12-2 (Continued)	

Subcategory 

Discharge 

Status 

Options Evaluated 

Since Proposal 

NODA Fin

Number of 

Sites 

Pound 

Equivalents 

(PE/yr)b 

Pounds (lbs/yr) 

Number 

of Sites 

Pound 

Equivalents 

(PE/yr)b 

Totalb 

TSS/Oil 

and Grease 

(as HEM) 

Railroad Line 

Maintenance 

Direct Option 10 31 865 300,188 17,531 

Option 6 NA 9 

Indirect Not Proposed NA 

Shipbuilding Dry 

Dock 

Direct Direct 6 1,925 10,762,301 8,523,580 6 

Indirect Not Proposed NA 

Source: EPA Costs & Loadings Model.
aBaseline loads reflect the load after treatment, or raw loads if there is no treatment in place.
bDoes not include sodium, calcium, total dissolved solids, and boron.
cEPA’s data collection efforts did not identify any direct discharging non-chromium anodizing facilities.
 12-27
 NA - Not applicable.

12.0 - Pollutant L

Table 12-3	

Summary of Selected Option Annual Pollutant Loadings Discharged by Subcat

12-28


Subcategory 

Discharge 

Status 

Options 

Evaluated Since 

Proposal 

NODA Final R

Number 

of Sites 

Pound 

Equivalents 

(PE/yr)b 

Pounds (lbs/yr) 

Number 

of Sites 

Pound 

Equivalents 

(PE/yr)b 

Totalb 

TSS/Oil and 

Grease 

(as HEM) 

General Metals Direct Option 2 1,521 1,011,672 43,517,771 1,508,435 228 263,433 

Indirect Option 2, 1 MGY 

cutoff 

2,354 508,173 158,758,380 3,957,147 NA 

Upgrade Option NA 429 89,012 

50% Local Limits NA 628 99,666 

Metal Finishing 

Job Shops 

Direct Option 2 24 1,707 292,154 5,618 NA 

Indirect Option 2 1,270 139,820 33,732,992 705,244 NA 

Upgrade Option NA 314 42,945 

Non-Chromium 

Anodizing 

Directc Option 2 

(model site) 

35 12,698 6,263,130 449,851 19 1,879 

Indirect Not Proposed NA 

Printed Wiring 

Board 

Direct Option 2 4 341 45,733 1,055 NA 

Indirect Option 2 840 114,167 38,526,836 1,100,894 NA 

Upgrade Option NA 354 42,068 

Steel Forming and 

Finishing 

Direct Option 2 Not Covered by MP&M 

Indirect Option 2 

Oily Wastes Direct Option 6 2,749 5,781 3,483,987 191,913 2,382 667 

Indirect Option 6, 2 MGY 

cutoff 

288 33,064 38,007,435 1,679,345 NA 
12.0 - Pollutant L

Table 12-3 (Continued)	

Subcategory 

Discharge 

Status 

Options 

Evaluated Since 

Proposal 

NODA Final R

Number 

of Sites 

Pound 

Equivalents 

(PE/yr)b 

Pounds (lbs/yr) 

Number 

of Sites 

Pound 

Equivalents 

(PE/yr)b 

Totalb 

TSS/Oil and 

Grease 

(as HEM) 

Railroad Line 

Maintenance 

Direct Option 10 31 832 228,830 12,674 NA 

Option 6 NA 9 

Indirect Not Proposed NA 

Shipbuilding Dry 

Dock 

Direct Direct 6 1,869 502,953 34,786 6 

Indirect Not Proposed NA 

Source: EPA Costs & Loadings Model.
aOption loads reflect the load after the implementation of the MP&M technology basis for each subcategory.
bDoes not include sodium, calcium, total dissolved solids, and boron.
cEPA’s data collection efforts did not identify any direct discharging non-chromium anodizing facilities.
 12-29
 NA - Not applicable.

12.0 - Pollutant L

Table 12-4	

Industry Pollutant Removals in Pounds (for Direct Dischargers)	

Subcategory 

Options 

Evaluated Since 

Proposal 

NODA Removals (lbs) Final Rule Removals (lbs) 

Total 

TSS/Oil and 

Grease 

(as HEM) 

Priority and 

Nonconventional 

Metals/Organics Total 

TSS/Oil and 

Grease (as HEM) 

Priority 

Nonconven

Metals/Or

General Metals Option 2 130,941,626 5,814,481 5,693,724 1,822,813 290,207 56,32

Metal Finishing Job 

Shops 

Option 2 658,666 15,492 35,661 NA 

Non-Chromium 

Anodizing 

Option 2 (model 

site) 

213,370,375 4,215,897 37,401,639 251,517 10,646 16,15

Printed Wiring Board Option 2 24,949 530 1,078 NA 

Steel Forming and 

Finishing 

Option 2 Not Covered by MP&M 

Oily Wastes Option 6 27,101,129 5,517,909 108,748 5,510,680 486,094 11,27

Railroad Line 

Maintenance 

Option 10 71,358 4,857 482 NA 

Option 6 NA NA 

Shipbuilding Dry Dock Option 10 10,259,349 8,488,793 1,796 NA 

12-30


Source: EPA Costs & Loadings Model.


Note: Loadings estimates presented in this table will not equal those presented in the EEBA. EEBA estimates do not include loadings for facilities that are projected to 

NA- Not applicable.

12.0 - Pollutant L

Table 12-5	

Industry Pollutant Removals in Pound-Equivalents	

12-31


Subcategory 

Discharge 

Status 

Options Evaluated Since 

Proposal 

NODA Final Rule 

Number of 

Sites 

Pollutant Removals 

(PE) 

Number of 

Sites 

Pollutant Rem

(PE) 

General Metals Direct Option 2 1,521 997,678 228 6,903 

Indirect Option 2, 1 MGY cutoff 2,354 1,360,332 NA 

Upgrade Option NA 429 39,734 

50% Local Limits NA 628 39,630 

Metal Finishing Job 

Shops 

Direct Option 2 24 1,652 NA 

Indirect Option 2 1,270 95,149 NA 

Upgrade Option NA 314 6,034 

Non-Chromium 

Anodizing 

Direct Option 2 (model site) 35 2,392,735 19 2,045 

Indirect Not Proposed NA 

Printed Wiring 

Board 

Direct Option 2 4 186 NA 

Indirect Option 2 840 153,653 NA 

Upgrade Option NA 354 5,157 

Steel Forming and 

Finishing 

Direct Option 2 Not Covered by MP&M 

Indirect Option 2 Not Covered by MP&M 

Oily Wastes Direct Option 6 2,749 5,367 2,382 2,684 

Indirect Option 6, 2 MGY cutoff 288 14,385 NA 

Railroad Line 

Maintenance 

Direct Option 10 31 34 NA 

Option 6 NA 9 NA 

Indirect Not Proposed NA 

Shipbuilding Dry 

Dock 

Direct Option 10 6 56 6 NA 

Indirect Not Proposed NA 

Source: EPA Costs & Loadings Model.


Note: Loadings estimates presented in this table will not equal those presented in the EEBA. EEBA estimates do not include loadings for facilities that are projected to 

NA - Not applicable.

13.0 - Non-Water Quality Impacts 

13.0 NON-WATER QUALITY IMPACTS 

Sections 304(b) and 306 of the Clean Water Act require EPA to consider nonwater quality environmental impacts (including energy requirements) associated with effluent 

limitations guidelines and standards. To comply with these requirements, EPA considered the 

potential impact of the MP&M final rule on energy consumption, air emissions, and solid waste 

generation. Section 9.0 discusses the final rule technology options. 

While it is difficult to balance environmental impacts across all media and energy 

use, the Agency has determined that the benefits associated with compliance with the limitations 

and standards justify the multimedia impacts identified in this section (see Chapters 12 through 

16 of the Economic, Environmental, and Benefits Analysis of the Final Metal Products and 

Machinery Rule (EEBA) (EPA-821-B-03-002) for a discussion on the environmental benefits 

associated with this final regulation). 

Section 13.1 discusses the energy requirements for implementing wastewater 

treatment technologies at MP&M facilities. Section 13.2 presents the impact of the technologies 

on air emissions, and Section 13.3 discusses the impact on wastewater treatment sludge and 

waste oil generation. Section 13.4 presents the reference used in this section. 

13.1 Energy Requirements 

EPA estimates that compliance with this rule will result in a net increase in energy 

consumption at MP&M facilities. Table 13-1 presents estimates of energy usage for the selected 

technology option. 

Table 13-1 

Energy Usage for the Selected Technology Option 

Selected Option 

Incremental 

Energy Requireda 

(kiloWatt hrs/yr) 

Basic Technology with Water Conservation and Pollution Prevention 

� Option 6: End-of-pipe chemical emulsion breaking and gravity separation; plus 

in-process flow control and pollution prevention technologies (Oily Wastes). 

350,676 

Source: EPA Costs & Loadings Model.
 a

The amount of additional energy required (from baseline) if the technology option is implemented, summed for all


regulated facilities.


This annual incremental net energy increase for the MP&M final rule is minimal 

(< 0.001 percent) when compared with the total electricity used by the entire United States in 

1997 (3,123 billion kiloWatt hours (KWH)) (1). Additionally, EPA expects that this small 

increase in energy usage will not result in any increase of air emissions impacts from the electric 

power generation facilities providing the additional energy. 

13-1

13.0 - Non-Water Quality Impacts 

13.2 Air Emissions Impacts 

The in-process and end-of-pipe technologies included in the technology options 

for this rule do not generate significant air emissions. The additional air emissions generated by 

the technology options will not hinder facilities’ ability to comply with EPA’s national emission 

standards for hazardous air pollutants (NESHAPs). 

EPA is developing NESHAPs under Section 112 of the Clean Air Act (CAA) to 

address air emissions of the hazardous air pollutants (HAPs) listed in Section 112(b) of the CAA. 

Below is a list of current and upcoming NESHAPs that affect MP&M sites (see EPA’s Air 

Toxics Web site, http://www.epa.gov/ttn/atw/, for more information and updates): 

� Chromium Emissions from Hard and Decorative Chromium Electroplating 

and Chromium Anodizing Tanks - Proposed December 16, 1993 and 

promulgated on January 25, 1995; 

� Halogenated Solvent Cleaning - Proposed November 29, 1993 and 

promulgated on December 2, 1994; 

� Aerospace Manufacturing - Proposed June 6, 1994 and promulgated on 

September 1, 1995; 

� Shipbuilding and Ship Repair (Surface Coating) - Proposed December 6, 

1994 and promulgated on December 15, 1995; 

� Large Appliances (Surface Coating) - Proposed December 22, 2000 and 

promulgated on July 23, 2002; 

� Metal Furniture (Surface Coating) - Proposed April 24, 2002; 

� Metal Can (Surface Coating) - Signed November 26, 2002; 

� Automobile and Light-Duty Truck Manufacturing (Surface Coating) -

Signed November 26, 2002; and 

� Miscellaneous Metal Parts and Products (Surface Coating) - Proposed 

August 13, 2002. 

These NESHAPs define the maximum achievable control technology (MACT) for 

emissions of HAPs. Like effluent guidelines, MACT standards are technology-based. The CAA 

specifies criteria for determining MACT for new and existing sources. 

Halogenated HAP solvents (e.g., methylene chloride, perchloroethylene, 

trichloroethylene, 1,1,1-trichloroethane, carbon tetrachloride, and chloroform) used for cleaning 

13-2

13.0 - Non-Water Quality Impacts 

in the MP&M industry can be a source of hazardous air emissions. EPA believes the final 

MP&M rule will not affect the use of solvents containing halogenated hazardous air pollutants in 

the MP&M industry. This rule neither requires nor discourages the use of aqueous cleaners in 

lieu of halogenated HAP solvents. 

Additionally, because the final rule would not allow any less stringent control of 

VOCs or organic HAPs than is currently in place at MP&M facilities, EPA does not predict any 

net increase in air emissions from volatilization or organic pollutants due to the final rule. As 

such, EPA expects no adverse air impacts to occur as a result of the final rule. 

13.3 Solid Waste Generation 

Solid waste generated at the regulated MP&M sites consists of waste oil removed 

in wastewater treatment. EPA estimates that compliance with this final rule will result in an 

increase in MP&M waste oil generation. 

Based on the Agency’s detailed questionnaire, EPA estimates that MP&M 

facilities covered by this final rule generated 13.5 million gallons of waste oil in 1996. Table 

13-2 presents the amount of additional waste oil expected to be generated as a result of 

implementing the technology option. 

Table 13-2 

Waste Oil Removed by the Selected Option 

Selected Option 

Incremental 

Waste Oil 

Removeda 

(million gal/yr) 

Basic Technology with Water Conservation and Pollution Prevention 

� Option 6: End-of-pipe chemical emulsion breaking and gravity separation; plus inprocess flow control and pollution prevention technologies (Oily Wastes). 

2.4 

Source: MP&M Costs & Loadings Model.
 a

The amount of additional oil removed (from baseline) if the technology option is implemented, summed for all


regulated facilities.


Removing oil from MP&M wastewater prior to discharge to surface waters results 

in an increase in waste oil generation from baseline to the final rule option (Option 6). The 

increase in waste oil generation reflects better removal of oil from the wastewater, and does not 

reflect an increase in overall oil use at MP&M facilities. 

MP&M facilities usually either recycle waste oil on or off site, or contract for offsite disposal of the waste oil as either a hazardous or nonhazardous waste. For the purpose of 

compliance cost estimation, EPA assumed that all sites contracted for off-site disposal of waste 

oil; however, EPA expects that some of the waste oil can be recycled either on or off site. 

13-3

13.0 - Non-Water Quality Impacts 

13.4 References 

1.	 The Energy Information Administration. Electric Power Annual 1998 Volume 1, 

Table A1, 1998. http://www.eia.doe.gov/. 

13-4

14.0 - Long-Term Averages and Effluent Limitations and Standards 

14.0
 LONG-TERM AVERAGES AND EFFLUENT LIMITATIONS AND 

STANDARDS 

This section presents the MP&M effluent guidelines for each regulatory level of 

control required by the Clean Water Act (CWA) for direct and indirect dischargers, and presents 

the technology basis for the limitations and standards. Section 2.0 provides more details on the 

different regulatory levels of control. Direct dischargers are sites that discharge wastewater to a 

surface water. Indirect dischargers are sites that discharge wastewater to a publicly owned 

treatment works (POTW). 

EPA is only promulgating limitations and standards for direct dischargers 

(existing and new) for one of the subcategories in the January 2001 proposal: Oily Wastes. 

These limitations and standards are codified in 40 CFR 438, Subpart A. The final limitations are 

concentration-based limitations with an allowable pH range. 

EPA decided not to establish limitations for existing and new direct dischargers in 

seven subcategories listed in the January 2001 proposal (General Metals, Metal Finishing Job 

Shops, Printed Wiring Board, Non-Chromium Anodizing, Steel Forming and Finishing, Railroad 

Line Maintenance, and Shipbuilding Dry Dock). EPA also decided not to establish standards for 

new and existing indirect dischargers (PSES and PSNS) for all eight subcategories listed in the 

January 2001 proposal (including the Oily Wastes Subcategory in the final MP&M rule). 

Sections 14.1 through 14.8 discuss EPA’s rationale for the selected technology 

options and summarize the effluent guidelines for each of the regulatory levels of control for 

each of the subcategories listed in the January 2001 proposal. Section 10.0 contains detailed 

information on those facilities whose data EPA used to calculate the BPT limitations, and 

presents the statistical methodology for developing numerical limitations. Section 9.0 describes 

in detail all of the MP&M technology options evaluated for the final rule, and Sections 11.0 and 

12.0 discuss estimated compliance costs and pollutant loadings and removals, respectively, for 

these technology options. All supporting economic and financial analyses can be found in the 

Economic, Environmental, and Benefits Analysis of the Final Metal Products & Machinery Rule 

(EEBA) (EPA-821-B-03-002). Cost-effectiveness analyses can be found in the EEBA and 

Section 26.0 of the rulemaking record, DCN 37900. 

EPA is promulgating performance-based limitations and standards to control 

direct discharges; these limitation and standards do not require the use of any particular pollution 

prevention or wastewater treatment technology. Rather, a facility may use any combination of 

pollution prevention and wastewater treatment technology to comply with the limitations. Direct 

dischargers must also comply with NPDES regulations (40 CFR 122). 

14.1 General Metals Subcategory 

EPA is not revising or establishing any limitations or standards for facilities that 

would have been subject to this subcategory. Such facilities will continue to be regulated by the 

14-1

14.0 - Long-Term Averages and Effluent Limitations and Standards 

General Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, 

as applicable. 

14.2 Metal Finishing Job Shops Subcategory 

EPA is not revising any limitations or standards for facilities that would have been 

subject to this subcategory. Such facilities will continue to be regulated by the General 

Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, as 

applicable. 

14.3 Non-Chromium Anodizing Subcategory 

EPA is not revising limitations or standards for any facilities that would have been 

subject to this subcategory. Such facilities will continue to be regulated by the General 

Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, as 

applicable. 

14.4 Printed Wiring Board Subcategory 

EPA is not revising any limitations or standards for facilities that would have been 

subject to this subcategory. Such facilities will continue to be regulated by the General 

Pretreatment Standards (Part 403), local limits, permit limits, and Parts 413 and/or 433, as 

applicable. 

14.5 Steel Forming and Finishing Subcategory 

EPA is not revising limitations or standards for any facilities that would have been 

subject to this subcategory. Such facilities will continue to be regulated by the General 

Pretreatment Standards (Part 403), local limits, permit limits, and Iron and Steel effluent 

limitations guidelines (Part 420) as applicable. 

14.6 Oily Wastes Subcategory 

EPA is promulgating limitations and standards for existing and new direct 

dischargers in the Oily Wastes Subcategory based on the proposed Option 6 technology (see 

Section 9.0). EPA is not promulgating pretreatment standards for existing or new indirect 

dischargers in this subcategory. 

14.6.1 Best Practicable Control Technology (BPT) 

As discussed in Section 9.7.1, EPA is establishing BPT pH limitations and daily 

maximum limitations for two pollutants, oil and grease as hexane extractable material (oil and 

grease (as HEM)) and total suspended solids (TSS), for direct dischargers in the Oily Wastes 

Subcategory based on the proposed technology option (Option 6). Option 6 technology includes 

14-2

14.0 - Long-Term Averages and Effluent Limitations and Standards 

the following: (1) in-process flow control and pollution prevention, and (2) oil/water separation 

by chemical emulsion breaking and skimming (see Section 9.0 for additional details on the 

Option 6 technology). 

In its analyses, EPA estimated that facilities will monitor once per month for oil 

and grease (as HEM) and TSS. EPA expects that 12 data points for each pollutant per year will 

yield a meaningful basis for establishing compliance with the promulgated limitations through 

long-term trends and short-term variability in oil and grease (as HEM) and TSS pollutant 

discharge loading patterns. 

Although EPA is not changing the technology basis from that proposed, EPA is 

revising all of the proposed Oily Wastes Subcategory BPT limitations. This is due to 

incorporation of additional data and revisions to the data sets used to calculate the promulgated 

limitations (see 67 FR 38754). 

Table 14-1 

BPT Effluent Limitations for the Oily Wastes Subcategory 

Regulated Parameter 

Maximum Daily 

mg/L (ppm) 

Total Suspended Solids (TSS) 62 

Oil and Grease (as HEM) 46 

pH a 

a

Discharges must remain within the pH range 6 to 9. 

These BPT limitations regulate process wastewater discharges from “oily 

operations” at existing or new direct dischargers engaged in manufacturing, rebuilding, or 

maintenance of metal parts, products, or machines used in any of the 16 industrial sectors listed 

in Section 1.1 and 40 CFR 438.1. EPA has defined “oily operation” in Section V.A of the 

preamble to the final rule, 40 CFR 438.2(f), and Appendix B to Part 438. 

Wastewater discharges from other subcategories listed in the January 2001 

proposal will continue to be regulated by existing categorical regulations (e.g., 40 CFR 413, 433, 

420), General Pretreatment Standards (40 CFR 403), local limits, or permit limits. When a 

facility segregates "oily operations" process wastewaters from other process wastewaters, the 

NPDES permit writer will use the limitations and standards in the final rule for those "oily 

operations" process wastewaters (40 CFR 438). When a facility commingles "oily operations" 

process wastewaters with other process wastewaters already covered by other effluent limitations 

guidelines or with process wastewaters from metal-bearing operations (as defined in 438.2), the 

entire commingled stream is not regulated by the final rule. This provision must be examined for 

each point source discharge at a given facility and is codified at 438.1(b). 

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14.0 - Long-Term Averages and Effluent Limitations and Standards 

14.6.2 Best Conventional Pollutant Control Technology (BCT) 

EPA is promulgating effluent limitations for conventional parameters (e.g., pH, 

TSS, oil and grease) equivalent to BPT for this subcategory because it identified no technologies 

that can achieve greater removals of conventional pollutants than the selected BPT technology 

basis that also pass the BCT cost test (see Section 9.7.2). 

14.6.3 Best Available Technology Economically Achievable (BAT) 

EPA proposed to control toxic and nonconventional pollutants by using BAT 

limitations based on Option 6 technology. As described in Section 9.7.3, EPA is not 

promulgating BAT limitations for specific pollutant parameters. EPA will achieve control of 

toxic organics and other priority and nonconventional pollutant discharges in Oily Wastes 

Subcategory process wastewaters through use of the oil and grease (as HEM) limitation. 

14.6.4 New Source Performance Standards (NSPS) 

EPA is promulgating NSPS that would control pH and the same conventional 

pollutants controlled at the BPT and BCT levels (see Section 9.7.4). 

14.6.5 Pretreatment Standards for Existing Sources (PSES) 

EPA proposed to establish PSES for existing indirect dischargers in the Oily 

Wastes Subcategory based on the Option 6 technology (i.e., the same technology basis that is 

being promulgated for BPT/BCT/NSPS for this subcategory) with a “low-flow” exclusion of 2 

million gallons per year (MGY) to reduce economic impacts on small businesses and 

administrative burden for control authorities. EPA is not promulgating PSES for existing indirect 

dischargers in the Oily Wastes Subcategory (see Section 9.7.5). These facilities remain subject to 

the General Pretreatment Standards (40 CFR 403) and local limits, as applicable. 

14.6.6 Pretreatment Standards for New Sources (PSNS) 

EPA proposed to establish PSNS for indirect dischargers in the Oily Wastes 

Subcategory based on the Option 6 technology (i.e., the same technology basis that is being 

promulgated for NSPS for this subcategory) with a “low-flow” exclusion of 2 MGY to reduce 

economic impacts on small businesses and reduce administrative burden to POTWs. EPA 

rejected Option 6 technology as the basis for PSNS in the Oily Wastes Subcategory. EPA has 

selected “no further regulation” for new Oily Wastes Subcategory indirect dischargers and is not 

revising PSNS for new Oily Wastes Subcategory indirect dischargers (see Section 9.7.6). These 

facilities remain subject to the General Pretreatment Standards (40 CFR 403) and local limits, as 

applicable. 

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14.0 - Long-Term Averages and Effluent Limitations and Standards 

14.7 Railroad Line Maintenance Subcategory 

EPA is not establishing limitations or standards for any facilities that would have 

been subject to this subcategory. Permit writers and control authorities will establish controls 

using best professional judgment (BPJ) to regulate wastewater discharges from these facilities. 

14.8 Shipbuilding Dry Dock Subcategory 

EPA is not establishing limitations or standards for any facilities that would have 

been subject to this subcategory. Permit writers and control authorities will establish controls 

using BPJ to regulate wastewater discharges from these facilities. 

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 15.0 - Implementation 

15.0 IMPLEMENTATION 

This section provides guidance to permit writers and the regulated community for 

implementing the MP&M effluent limitations guidelines and standards. Section 15.1 describes 

the MP&M effluent guidelines’ applicability, Section 15.2 summarizes compliance dates, 

Section 15.3 presents guidance on developing limits, and Section 15.4 summarizes monitoring 

requirements. 

15.1 Applicability of the MP&M Effluent Guidelines 

The MP&M Point Source Category regulates oily operation process wastewater 

discharges to surface waters from existing or new industrial facilities (including facilities owned 

and operated by federal, state, or local governments) engaged in manufacturing, rebuilding, or 

maintenance of metal parts, products, or machines for use in any of the 16 MP&M industrial 

sectors. Please note the underlined language in the previous sentence. A facility may be subject 

to the MP&M effluent guidelines even if it is not in one of the MP&M industrial sectors. For 

example, EPA considers a facility performing machining as part of the “Bus & Truck” industrial 

sector if it maintains metal parts for truck trailers. Process wastewater means wastewater as 

defined at 40 CFR 122 and 401, and includes wastewater from air pollution control devices (see 

40 CFR 438.2(g)). EPA notes that the MP&M effluent guidelines only regulate process 

wastewaters from wet air pollution control for organic constituents (see 40 CFR 438.2(f)). Oily 

operations are listed at 40 CFR 438.2(g) and defined in Appendix B to Part 438 (see also Section 

4.0 of this document). 

Manufacturing is the series of unit operations necessary to produce metal products 

and is generally performed in a production environment. Rebuilding/maintenance is the series of 

unit operations necessary to disassemble used metal products into components, replace the 

components or subassemblies or restore them to original function, and reassemble the metal 

product. Rebuilding and maintenance operations are intended to keep metal products in 

operating condition and can be performed in either a production or a nonproduction environment. 

The 16 industrial sectors are described in further detail in the following subsection. Additionally, 

some facilities are excluded by definition from the MP&M effluent guidelines (see Section 

15.1.3). 

EPA collected data on a wide variety of facilities engaged in manufacturing, 

rebuilding, or maintenance of metal parts, products, or machines for use in the 16 MP&M 

industrial sectors (see Section 3.0). The range of manufacturing, rebuilding, or maintenance 

operations involved the following types of metal parts, products, or machines: (1) parts, products, 

or machines composed of metal or metal alloys, and/or (2) parts, products, or machines with 

metal surfaces. In particular, EPA notes that metal parts or products can have a nonmetal 

substrate with a metal surface. For example, a plastic part with a metal surface is considered a 

“metal part” under MP&M effluent guidelines when it is manufactured, rebuilt, or maintained for 

use in one of the 16 industrial sectors. Oily operation process wastewaters on this metal part 

would be subject to the MP&M effluent guidelines provided there are no exclusions from the 

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 15.0 - Implementation 

guidelines as described in the applicability section of the rule. Another specific example of a 

metal part is a laminate composed of a metal surface and nonmetal substrate. In this particular 

case, the laminate manufacturing process involves pressing a fiberglass web between two sheets 

of copper foil for a part in electronic equipment. If a facility performs oily operations on this 

laminate (a “metal part” because it has a metal surface), then any resulting process wastewater 

would be subject to the MP&M effluent guidelines provided there are no exclusions from the 

guidelines as described in the applicability section of the rule. EPA notes that lead crystal is not 

a metal part or product as it does not have a metal surface. 

15.1.1 MP&M Industrial Sectors 

The MP&M Point Source Category encompasses manufacturing, rebuilding, or 

maintenance of metal parts, products, or machines for use in the following industrial sectors: 

� Aerospace;


� Aircraft;


� Bus and Truck; 


� Electronic Equipment;


� Hardware;


� Household Equipment;


� Instruments;


� Mobile Industrial Equipment;


� Motor Vehicle;


� Office Machines;


� Ordnance; 


� Precious Metals and Jewelry;


� Railroad;


� Ships and Boats;


� Stationary Industrial Equipment; and


� Miscellaneous Metal Products.


The MP&M sectors manufacture, maintain, and rebuild metal products under 

more than 200 different Standard Industrial Classification (SIC) codes. Typical products in the 

MP&M industrial sectors are listed in Appendix A to 40 CFR 438 and Appendix A of this 

document includes a list of example SIC codes and North American Industrial Classification 

System (NAICS) codes that may further clarify the description of the above industrial sectors. 

The final rule also covers direct discharges of wastewater from MP&M operations 

related to maintenance and repair of metal products, parts, and machinery at military installations 

(i.e., federal facilities) as well as facilities owned or operated by state or local governments. For 

example, the rule covers wastewater generated from the maintenance and repair of aircraft, cars, 

trucks, buses, tanks (or other armor personnel carriers), and industrial equipment – these 

operations are commonly performed at military installations and state or local government 

maintenance facilities. 

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 15.0 - Implementation 

The MP&M effluent guidelines do not apply to maintenance or repair of metal 

parts, products, or machines that takes place only as ancillary activities at facilities not included 

in the 16 MP&M industrial sectors. EPA estimates that these ancillary repair and maintenance 

activities would typically discharge de minimis quantities of process wastewater. For example, 

wastewater discharges from repair of metal parts at oil and gas extraction facilities are not subject 

to the final rule. The Agency has concluded that permit writers will establish limits using best 

professional judgment (BPJ) to regulate wastewater discharges from ancillary waste streams for 

direct dischargers (see 66 FR 433). EPA has not received any information during the rulemaking 

that would contradict this conclusion. 

Alternatively, EPA is including oily operation process wastewater discharges from 

activities related to maintaining or repairing aircraft or other related (metal) equipment (e.g., 

baggage-handling vehicles) at airports when those oily operation process wastewaters are not 

already covered by another effluent guidelines regulation (see Section 15.1.3). 

15.1.2 Regulated Subcategory in the MP&M Effluent Guidelines 

EPA evaluated the following subcategories for the MP&M final rule: General 

Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Board, Steel 

Forming and Finishing, Oily Wastes, Railroad Line Maintenance, and Shipbuilding Dry Dock. 

See Section 6.0 for a further discussion on the subcategorization structure EPA evaluated for the 

final rule. As discussed in Section 9.0, the MP&M effluent guidelines apply only to facilities in 

the Oily Wastes Subcategory (40 CFR 438, Subpart A). The Oily Wastes Subcategory applies to 

all of the 16 industrial sectors listed in the previous section. Section 6.0 further defines the Oily 

Wastes Subcategory. 

15.1.3 Facilities Not Subject to the MP&M Effluent Guidelines 

Certain facilities and process wastewaters are not subject to the MP&M 

guidelines. These are listed at 40 CFR 438.1 (b) through (e) and are more fully described below. 

Overlap With Metal-Bearing Operations and Existing Effluent Limitations 

Guidelines and Standards 

MP&M effluent guidelines do not apply to process wastewaters from 

metal-bearing operations (see Section 4.0) or process wastewaters that are subject to the 

limitations and standards of other effluent limitations guidelines (e.g., Metal Finishing (40 CFR 

433) or Iron and Steel Manufacturing (40 CFR 420)). EPA also established effluent guidelines 

for 11 other industries that may perform unit operations or process parts that are sometimes 

found at MP&M sites. These effluent guidelines are: 

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 15.0 - Implementation 

� Electroplating (40 CFR 413)1

;


� Nonferrous Metals Manufacturing (40 CFR 421);


� Ferroalloy Manufacturing (40 CFR 424);


� Battery Manufacturing (40 CFR 461);


� Metal Molding & Casting (40 CFR 464);


� Coil Coating (40 CFR 465);


� Porcelain Enameling (40 CFR 466);


� Aluminum Forming (40 CFR 467);


� Copper Forming (40 CFR 468);


� Electrical & Electronic Components (40 CFR 469); and


� Nonferrous Metals Forming & Metal Powders (40 CFR 471).


Under the proposed rule, there was overlapping coverage between Parts 413, 433, 

and the proposed Part 438. See Table 15-1, which clarifies the coverage of Parts 413 and 433 

and new Part 438 with respect to the subcategories evaluated for regulation in the final rule. 

In general, when unit operations and their associated wastewater discharges are 

already covered by an existing effluent guideline, they will remain regulated under that effluent 

guideline. Additionally, these wastewater discharges will continue to be regulated by General 

Pretreatment Standards (40 CFR 403), local limits, and permit limits, as applicable. The 

limitations and standards in the Oily Wastes Subcategory (40 CFR 438, Subpart A) apply to 

process wastewater generated by “oily operations” that are discharged directly to surface waters 

and are not otherwise covered by other effluent limitations guidelines and standards. 

The MP&M effluent guidelines also do not apply to process wastewaters from 

oily operations commingled with process wastewaters already covered by other effluent 

limitations guidelines or with process wastewaters from metal-bearing operations. When a 

facility segregates oily operation process wastewaters from other process wastewaters, the 

NPDES permit writer will use the MP&M limitations and standards for those oily operation 

process wastewaters and use the applicable limitations and standards for their other discharges. 

When a facility commingles oily operation process wastewaters with other process wastewaters 

already covered by other effluent limitations guidelines or with process wastewaters from metalbearing operations, the entire commingled stream is not regulated by the MP&M limitations and 

standards. This provision must be examined for each point source discharge at a given facility 

and is codified at 40 CFR 438.1(b). 

Table 15-1 summarizes the coverage of industrial operations by each MP&M 

subcategory evaluated for the final rule. 

1

Part 413 applies only to indirect discharging job shops and independent printed circuit board manufacturers in 

operation prior to August 31, 1982. 

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 15.0 - Implementation 

Table 15-1	

Clarification of Coverage by MP&M Subcategory 

Evaluated for the Final Rule 

Subcategory Evaluated for the 

Final Rule 

Continue to 

Cover Under 

40 CFR 413a 

(Electroplating) 

Continue to 

Cover Under 

40 CFR 433 

(Metal Finishing) 

Cover Under 

40 CFR 438 

(Metal Products & 

Machinery) 

General Metals (Including 

Continuous Electroplaters)

b 

Existing indirect 

dischargers covered by 

Part 413. 

New and existing 

direct and indirect 

dischargers covered 

by Part 433. 

None 

Metal Finishing Job Shops Existing indirect 

dischargers covered by 

Part 413. 

New and existing 

direct and indirect 

dischargers covered 

by Part 433. 

None 

Non-Chromium 

Anodizing 

Existing indirect 

dischargers covered by 

Part 413. 

New and existing 

direct and indirect 

dischargers covered 

by Part 433. 

None 

Printed Wiring Board 

(Printed Circuit Board) 

Existing indirect 

dischargers covered by 

Part 413. 

New and existing 

direct and indirect 

dischargers covered 

by Part 433. 

None 

Steel Forming and Finishingc NA NA None 

Oily Wastes NA NA All new and existing 

direct dischargers under 

this subcategory 

(See 438.10). 

Railroad Line Maintenance NA NA None 

Shipbuilding Dry Dock NA NA None 

NA - Not applicable.
 a

Part 413 applies only to indirect discharging job shops and independent printed circuit board manufacturers in


operation prior to August 31, 1982.
 b

Part 413 specifically excludes continuous electroplaters. Instead they are covered by Part 433.
 c

These facilities will continue to be subject to Part 420.


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 15.0 - Implementation 

Applicability of MP&M Effluent Guidelines to Washing Operations 

Wastewater discharges resulting from the washing of cars, aircraft, or other 

vehicles, when performed only for aesthetic or cosmetic purposes, are not subject to the MP&M 

effluent guidelines. Direct discharges resulting from the washing of cars, aircraft, or other 

vehicles, when performed as a preparatory step prior to one or more successive manufacturing, 

rebuilding, or maintenance operations, are subject to the MP&M effluent guidelines. This 

provision is codified at 40 CFR 438.1(c). For example, if an auto repair facility washes a vehicle 

in order to perform painting (an oily operation covered by the final rule), that wash water from 

the vehicle is considered an oily operation process wastewater. Aesthetic or cosmetic wastewater 

discharges commingled with directly discharged MP&M oily operation process wastewaters 

must be accounted for as nonregulated wastewaters using the building-block approach to develop 

facility-specific permits limits (see Section 15.3 for additional information on using the buildingblock approach). 

Applicability of MP&M Effluent Guidelines to Railroad Line Maintenance 

Facilities and Railroad Overhaul or Heavy Maintenance Facilities 

Wastewater discharges from railroad line maintenance facilities are not subject to 

the MP&M effluent guidelines. Wastewater discharges from railroad overhaul or heavy 

maintenance facilities may be covered by the MP&M effluent guidelines (Subpart A), the Metal 

Finishing Point Source Category (40 CFR 433), or by other effluent limitations guidelines, as 

applicable. This provision is codified at 40 CFR 438.1(d). 

Facilities engaged in the manufacture, overhaul, or heavy maintenance of railroad 

engines, cars, car-wheel trucks, or similar parts or machines (“railroad overhaul or heavy 

maintenance facilities”) typically perform different unit operations than railroad line maintenance 

facilities. Railroad line maintenance facilities perform routine cleaning and light maintenance on 

railroad engines, cars, car-wheel trucks, or similar parts or machines, and discharge wastewater 

exclusively from oily operations. These facilities only perform one or more of the following 

operations: assembly/disassembly, floor cleaning, maintenance machining (wheel truing), 

touch-up painting, and washing. 

Railroad overhaul or heavy maintenance facilities are engaged in the manufacture, 

overhaul, or heavy maintenance of railroad engines, cars, car-wheel trucks, or similar parts or 

machines. These facilities typically perform one or more of the same operations as railroad line 

maintenance facilities and one or more of the following operations: abrasive blasting, alkaline 

cleaning, aqueous degreasing, corrosion preventive coating, electrical discharge machining, 

grinding, heat treating, impact deformation, painting, plasma arc machining, polishing, pressure 

deformation, soldering/brazing, stripping (paint), testing, thermal cutting, and welding. 

Permit writers will need to examine operations at each railroad overhaul or heavy 

maintenance facility to determine whether they fall under the MP&M effluent guidelines, the 

Metal Finishing Point Source Category (40 CFR 433), or other effluent limitations guidelines. 

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 15.0 - Implementation 

For example, process wastewaters from metal-bearing operations (e.g., stripping (paint)) at 

railroad overhaul or heavy maintenance facilities are not subject to the MP&M effluent 

guidelines (i.e., stripping (paint) is a metal-bearing operation). 

Other Wastewaters Not Subject to the MP&M Effluent Guidelines 

Other wastewaters and facilities not subject to the MP&M effluent guidelines are 

codified at 40 CFR 438.1(e) and are described below. 

The MP&M effluent guidelines do not apply to nonprocess wastewater. 

Nonprocess wastewater means sanitary wastewater, noncontact cooling water, water from 

laundering, and noncontact stormwater. Nonprocess wastewater also includes wastewater 

discharges from nonindustrial sources such as residential housing, schools, churches, recreational 

parks, shopping centers as well as wastewater discharges from gas stations, utility plants, and 

hospitals. EPA considers stormwater that is commingled with MP&M oily operation process 

wastewater (i.e., contact stormwater) prior to treatment or discharge subject to the MP&M 

effluent guidelines. Sanitary wastewater, noncontact cooling water, water from laundering, and 

noncontact stormwater commingled with directly discharged MP&M oily operation process 

wastewaters must be accounted for as nonregulated wastewaters using the building-block 

approach to develop facility specific permits limits (see Section 15.3). 

The MP&M effluent guidelines also do not apply to wastewater discharges from 

oily operations introduced into a publicly owned treatment works (POTW) or a federally owned 

and operated treatment works treating domestic sewage (TWTDS), as defined at 40 CFR 122.2. 

These wastewater discharges will be subject to General Pretreatment Standards (40 CFR 403), 

local limits, permit limits, and other effluent guidelines, as applicable. 

The MP&M effluent guidelines also do not apply to wastewater discharges in or 

on dry docks and similar structures, such as graving docks, building ways, marine railways, lift 

barges at shipbuilding facilities (or shipyards), and ships that are afloat. This provision is 

codified at 40 CFR 438(e)(5) and applies only to process wastewater generated and discharged 

from oily operations and metal-bearing operations inside and outside ships (including bilge water 

and dry dock stormwater) that occur in or on dry docks or similar structures. 

In addition to these dry dock wastewaters, three other types of water streams are in 

or on dry docks and similar structures: flooding water, dry dock ballast water, and stormwater. 

Flooding water enters and exits the dry dock or similar structure prior to performing any MP&M 

operations. For example, in a graving dock, the gates are opened, allowing flooding water in and 

ships to float inside the chamber. Then the flooding water is drained, leaving the ship’s exterior 

exposed so shipyard employees can repair and maintain the ship’s hull. Dry dock ballast water 

serves a similar purpose. It is used to lower (or sink) a floating dry dock so that a ship can float 

over it. Then the dry dock ballast water is pumped out, raising the dry dock with the ship on top. 

Flooding water and dry dock ballast water are not directly associated with MP&M operations. 

Finally, because these structures are located outdoors and are exposed to the elements, 

15-7

 15.0 - Implementation 

stormwater may fall in or on the dry dock or similar structures. All three of these wastewaters 

(i.e., flooding water, dry dock ballast water, and stormwater) are excluded from the scope of the 

MP&M effluent guidelines. 

However, the Agency is including direct discharges of process wastewater from 

oily operations that is generated at other shipyard locations (“on-shore” operations) in the 

MP&M regulation rule (assuming the other exclusions of Parts 438.1 and 438.10 do not apply). 

EPA included wastewaters from these oily “on-shore” shipbuilding operations (e.g., machining, 

floor cleaning, solvent degreasing, dye penetrant testing, and grinding) in the Oily Wastes 

Subcategory. Such oily operations are typically found in a machine shop in the shipyard. 

Wastewaters subject to the Shipbuilding Dry Dock exclusion commingled with directly 

discharged MP&M oily operation process wastewaters must be accounted for as nonregulated 

wastewaters using the building-block approach to develop facility specific permits limits (see 

Section 15.3). 

Also, EPA is not including wastewater generated onboard ships when they are 

afloat (i.e., not in dry docks or similar structures). For U.S. military ships, EPA is in the process 

of establishing standards under the Uniform National Discharge Standards (UNDS) pursuant to 

Section 312(n) of the Clean Water Act (CWA) (see 64 F.R. 25125; May 10, 1999) to regulate 

discharges of wastewater generated onboard these ships when they are in U.S. waters and are 

afloat (e.g., at a shipyard’s dock). 

For reasons discussed in the preamble to the final rule and Section 9.0, wastewater 

generated by facilities primarily performing drum reconditioning and cleaning to prepare metal 

drums for resale, reuse, or disposal are also not subject to the MP&M effluent guidelines. This 

provision only covers facilities in the Industrial Container and Drum Cleaning (ICDC) industry. 

This industry is within the 1987 Standard Industrial Classification (SIC) Code 7699 (Repair 

Shops and Related Services, Not Elsewhere Classified). All other facilities in this SIC code are 

included in the “Miscellaneous Metal Products” MP&M industrial sector (see Appendix A and 

Section 15.1.1). The ICDC industry includes facilities that clean and recondition metal and 

plastic drums and intermediate bulk containers (IBCs) for resale, reuse, or disposal. ICDC 

facilities can be further classified as facilities that either burn open-head steel drums or wash 

plastic or tight-head (i.e., bung-type) steel drums and IBCs. Most ICDC facilities purchase used 

drums or containers that they clean and recondition for resale. 

EPA estimates that most ICDC facilities discharge ICDC wastewater and that all 

or almost all of these facilities discharge indirectly to a POTW. EPA has not identified any 

facilities that discharge directly to surface waters. EPA also estimates that a portion of the 

industry achieves zero discharge by hauling the wastewater to a centralized waste treatment 

facility, or disposing of the wastewater by land application or evaporation. Alternatively, some 

ICDC facilities achieve zero discharge by recycling or reusing 100 percent of its wastewater (see 

Section 22.1, DCN 17933 and Section 24.1, DCN 17853 of the rulemaking record). 

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 15.0 - Implementation 

For reasons discussed in the preamble to the final rule and Section 9.0, the 

following wastewater discharges are also not subject to the MP&M effluent guidelines: 

� Process wastewater generated by maintenance and repair activities at 

gasoline service stations (SIC Code 5541), passenger car rental facilities, 

or utility trailer and recreational vehicle rental facilities (SIC Code 7514 or 

7519); and 

� Wastewater from gravure cylinder and metallic platemaking conducted 

within or for printing and publishing facilities (SIC Code 2796). 

Figure 15-1 shows the MP&M permitting process flow chart. 

15.2 Compliance Dates 

New and reissued federal and state NPDES permits to MP&M direct dischargers 

must include the limitations and standards in the MP&M effluent guidelines. The permits must 

require immediate compliance with such limitations. If the permitting authority wishes to 

provide additional time for compliance, the permit authority should consider issuance of an 

enforcement order that provides for a schedule for compliance. 

New sources must comply with the new source performance standards (NSPS) of 

the MP&M rule at the time they commence discharging MP&M process wastewater. The 

Agency considers a discharger a new source if its construction commences 30 days after the 

publication date of the final rule in the Federal Register. 

15.3 Limits Development 

To develop limits for process wastewaters covered by the MP&M effluent 

guidelines, a permit writer must first determine if the process wastewater is subject to the 

regulation by determining the type of discharge (i.e., direct) and examining the unit operation(s) 

that generate the process wastewater (see Section 15.1 and Section 6.0). This requires careful 

consideration of the applicability criteria in Sections 438.1 and 438.10 of the final rule. After the 

permit writer determines that a process wastewater is subject to the MP&M effluent guidelines, 

the next step is to determine the applicable limitations and standards. Table 15-2 presents the 

concentration-based MP&M effluent guidelines for new and existing direct dischargers in the 

Oily Wastes Subcategory (40 CFR 438, Subpart A). The permit writer must then apply these 

limitations and standards to the MP&M process wastewater directly discharged from the facility. 

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 15.0 - Implementation

15-10

Figure 15-1. MP&M Permitting Process Flow Chart
15.0 - Implementation 

Table 15-2 

Effluent Limitations Guidelines for the MP&M Point Source Category 

(40 CFR 438) 

BPT/BCT/NSPS - Oily Wastes Subcategory 

Regulated Parameter 

Maximum Daily 

mg/L (ppm) 

Total Suspended Solids (TSS) 62 

Oil and Grease (as HEM) 46 

pH a 

a

Discharges must remain within the pH range 6 to 9. 

When oily operations are commingled prior to treatment or discharged with 

nonprocess (e.g., noncontact cooling water) or nonregulated wastewater (e.g., wastewater from 

aesthetic cleaning of vehicles), the permit writer will establish nonregulated limitations for such 

streams on a BPJ basis. The permit writer will establish limitations for the combined stream 

using the “building-block” approach, using a flow-weighted combination of the applicable 

guideline limitations (found in Table 15-2) and the BPJ limitation for the nonprocess wastewater 

or nonregulated waste stream. For further information, see EPA NPDES Permit Writers Manual, 

Chapter 5, pp. 61-63 (1). 

Although EPA is not promulgating mass-based limitations in the final MP&M 

rule, permit writers may want to develop mass-based limitations, if appropriate (e.g., a facility 

does not have adequate water conservation practices). The National Pollutant Discharge 

Elimination System (NPDES) regulations at 40 CFR 122.45(f) require permit writers to develop 

mass-based limitations for direct dischargers except in cases where the limitations are expressed 

in other units of measurement (e.g., a concentration). 

For MP&M facilities that have good water conservation practices, concentrationbased rather than mass-based effluent limitations may be sufficient. However, the Agency 

anticipates that MP&M facilities that have been using the best pollution prevention and water 

conservation practices may request that the permit writer establish mass-based limits in their 

permit. 

Since MP&M effluent guidelines are concentration-based limitations and 

standards, NPDES permit writers will include these limitations and standards in NPDES permits 

for MP&M facilities. NPDES permit writers may also establish mass-based limits in addition to 

the MP&M concentration-based limitations and standards for MP&M facilities (see 

122.45(f)(2)). In such cases, the NPDES permit will require the permittee to comply with both 

mass-based and concentration-based limits. 

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15.0 - Implementation 

Because EPA did not promulgate mass-based limitations and because it did not 

codify the method to determine the flow rate in these cases, the permit writer may use methods 

other than historical flow and production data to calculate mass-based limitations. EPA has 

published several documents that provide guidance for determining the appropriate process 

wastewater flow rate and establishing mass-based limitations (1, 2, 3). 

EPA based the final concentration-based MP&M effluent limitations on the 

performance of in-process pollution prevention and flow-reduction technologies followed by 

end-of-pipe treatment. In-process technologies include: conductivity meters, flow restrictors, and 

countercurrent cascade rinsing for flowing rinses; at-the-source machine coolant recycling; and 

at-the-source paint curtain recycling. The end-of-pipe treatment for the Oily Wastes Subcategory 

is chemical emulsion breaking and oil/water separation (see Sections 8.0 and 9.0). EPA is 

promulgating performance-based limitations and standards to control direct discharges; these 

limitations and standards do not require the use of any particular pollution prevention or 

wastewater treatment technology. Rather, a facility may use any combination of pollution 

prevention and wastewater treatment technology to comply with the limitations. Direct 

dischargers must also comply with other applicable regulations (e.g., NPDES regulations (40 

CFR 122)). 

The MP&M effluent guidelines also do not apply to process wastewaters from 

oily operations commingled with process wastewaters already subject to other effluent 

limitations guidelines or with process wastewaters from metal-bearing operations. When a 

facility segregates oily operation process wastewaters from other process wastewaters, the 

NPDES permit writer will apply the MP&M limitations and standards for those oily operation 

process wastewaters (at that outfall) and apply the applicable limitations and standards for their 

other discharges (at the other outfall(s)). For additional guidance regarding limits development, 

see EPA’s NPDES Permit Writers’ Manual (1). 

15.4 Compliance Monitoring 

Permit writers must establish requirements for regulated facilities to monitor their 

effluent to ensure that they are complying with permit limitations. As specified in 40 CFR 

122.41, 122.44, and 122.48, all NPDES permits must specify requirements for using, 

maintaining, and installing (if appropriate) monitoring equipment; monitoring type, intervals, and 

frequencies that will provide representative data; analytical methods; and reporting and 

recordkeeping. The NPDES program requires permittees (with certain specific exceptions) to 

monitor for limited pollutants and report data at least once per year. 

The Agency has not promulgated specific monitoring requirements or monitoring 

frequencies in the MP&M regulation; therefore, permit authorities may establish monitoring 

requirements and monitoring frequencies at their discretion. The Agency notes, however, that in 

developing the Part 438 limitations, EPA considered a monthly sampling frequency. In addition, 

Part 136 requires facilities to collect grab samples for oil and grease. In developing the Part 438 

oil and grease limitations, EPA generally collected four grab samples in a 24-hour monitoring 

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15.0 - Implementation 

day. The sample types for pH can range from a one-time grab sample during a monitoring day to 

continuous sampling for a monitoring day where pH is a critical aspect of the wastewater treated 

or the wastewater treatment operation. 

15.5 References 

1.	 U.S. Environmental Protection Agency. NPDES Permit Writers’ Manual. EPA833-B-96-003, December 1996. 

2.	 U.S. Environmental Protection Agency. Guidance Manual For the Use of 

Production-Based Pretreatment Standards and the Combined Wastestream 

Formula. EPA-833-B-85-201, September 1985. 

3.	 U.S. Environmental Protection Agency. Guidance Manual for Electroplating and 

Metal Finishing Pretreatment Standards. EPA-440/1-84-091g, February 1984. 

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16.0 - Glossary/List of Acronyms 

16.0 GLOSSARY OF TERMS 

This glossary includes a collection of the terms used in this document and an 

explanation of each term. To the extent that definitions and explanations provided in this 

glossary differ from those in EPA regulations or other official documents, they are intended for 

use in understanding this manual only. 

Act - The Clean Water Act. 

Administrator - The Administrator of the U.S. Environmental Protection Agency. 

Agency - U.S. Environmental Protection Agency (also referred to as “EPA”). 

Ambient Water Quality Criteria (AWQC) - Water quality criteria set ambient levels of 

individual pollutants or parameters, or describe conditions of a water body that, if met, will 

generally protect the designated use of the water. Water quality criteria are developed to protect 

aquatic life and human health, and, in some cases, wildlife from the deleterious effects of 

pollutants. 

AMSA - Association of Metropolitan Sewerage Agencies 

Best Available Technology Economically Achievable (BAT) - Technology-based standard 

established by the Clean Water Act (CWA) as the most appropriate means available on a national 

basis for controlling the direct discharge of toxic and nonconventional pollutants to navigable 

waters. BAT effluent limitations guidelines, in general, represent the best existing performance 

of treatment technologies that are economically achievable within an industrial point source 

category or subcategory. Best available technology economically achievable is defined by 

Section 304(b)(2)(B) of the Clean Water Act. 

Best Conventional Pollutant Control Technology (BCT) - Technology based standard for the 

discharge from existing industrial point sources of conventional pollutants including BOD, TSS, 

fecal coliform, pH, oil and grease. The BCT is established in light of a two-part “cost 

reasonableness” test which compares the cost for an industry to reduce its pollutant discharge 

with the cost to a POTW for similar levels of reduction of a pollutant loading. The second test 

examines the cost-effectiveness of additional industrial treatment beyond BPT. EPA must find 

limits which are reasonable under both tests before establishing them as BCT. 

Best Management Practices (BMP) - Sections 304(e), 308(a), 402(a), and 501(a) of the CWA 

authorize the Administrator to prescribe BMPs as part of effluent limitations guidelines and 

standards or as part of a permit. 

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16.0 - Glossary/List of Acronyms 

Best Practicable Control Technology Currently Available (BPT) - The first level of 

technology-based standards established by the CWA to control pollutants discharged to waters of 

the U.S. BPT effluent limitations guidelines are generally based on the average of the best 

existing performance by plants within an industrial category or subcategory. 

Best Professional Judgment (BPJ) - Best professional judgement. The method used by permit 

writers to develop technology-based NPDES permit conditions on a case-by-case basis using all 

reasonably available and relevant data. 

Biochemical Oxygen Demand (BOD) - A measurement of the amount of oxygen utilized by the 

decomposition of organic material, over a specified time period (usually 5 days) in a wastewater 

sample; it is used as a measurement of the readily decomposable organic content of a wastewater 

(see Appendix B). 

Categorical Industrial User (CIU) - An industrial user subject to National categorical 

pretreatment standards. 

Categorical Pretreatment Standards - Limitations on pollutant discharges to publicly owned 

treatment works promulgated by EPA in accordance with Section 307 of the Clean Water Act 

that apply to specified process wastewaters of particular industrial categories. 

Chemical Oxygen Demand (COD) - A measure of the oxygen-consuming capacity of inorganic 

and organic matter present in wastewater. COD is expressed as the amount of oxygen consumed 

in mg/l. Results do not necessarily correlate to the biochemical oxygen demand (BOD) because 

the chemical oxidant may react with substances that bacteria do not stabilize (see Appendix B). 

Clean Air Act (CAA) - Clean Air Act (42 U.S.C. 7401 et seq., as amended). 

Clean Water Act (CWA) - 33 U.S.C. 1251 et seq., as amended. 

Code of Federal Regulations (CFR) - These regulations are published by the U.S. Government 

Printing Office. A codification of the general and permanent rules published in the Federal 

Register by the executive departments and agencies of the federal government. Title 40 of the 

CFR contains the environmental regulations. 

Composite Sample - Sample composed of two or more discrete samples. The aggregate sample 

will reflect the average water quality covering the compositing or sample period. 

Confidential Business Information (CBI) - Section 308 of the CWA authorizes EPA to collect 

information, including confidential business information, in support of developing effluent 

guidelines. When requested to do so, EPA is required to consider information to be confidential 

and to treat it accordingly if disclosure would divulge methods or processes entitled to protection 

as trade secrets. 

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16.0 - Glossary/List of Acronyms 

Contract Hauling - The removal of any waste stream from a site by a company authorized to 

transport and dispose of the waste, excluding discharges to sewers or surface waters. 

Control Authority - The term “control authority” as used in Section 403.12 refers to: (1) the 

POTW if the POTW’s submission for its pretreatment program (§403.3(t)(1)) has been approved 

in accordance with the requirements of §403.11; or (2) the approval authority if the submission 

has not been approved. 

Conventional Pollutants - Pollutants typical of municipal sewage, and for which municipal 

secondary treatment plants are typically designed; defined by Federal Regulation (40 CFR 

§401.16) as BOD, TSS, fecal coliform bacteria, oil and grease, and pH. 

Corrosion preventive coating - The application of removable oily or organic solutions to 

protect metal surfaces against corrosive environments. Corrosion preventive coatings include, but 

are not limited to: petrolatum compounds, oils, hard dry-film compounds, solvent-cutback 

petroleum-based compounds, emulsions, water-displacing polar compounds, and fingerprint 

removers and neutralizers. Corrosion preventive coating does not include electroplating, or 

chemical conversion coating operations. 

Cost-effectiveness (CE) - A ratio of compliance costs (in 1981$) to the toxic pounds of 

pollutants removed in terms of pound-equivalents (PE). 

Daily Discharge - The discharge of a pollutant measured during any 24- hour period that 

reasonably represents a calendar day for purposes of sampling. For pollutants with limitations 

expressed in units of mass, the daily discharge is calculated as the total mass of the pollutant 

discharged during the day. For pollutants with limitations expressed in other units of 

measurement (e.g., concentration) the daily discharge is calculated as the average measurement 

of the pollutant throughout the day (see 40 CFR §122.2). 

Direct Capital Costs - One-time capital costs associated with the purchase, installation, and 

delivery of a specific technology. The MP&M cost model estimates direct capital costs. 

Direct Discharger - An industrial discharger that introduces wastewater to a water of the United 

States with or without treatment by the discharger. 

Director - The Regional Administrator or State Director, as the context requires, or an 

authorized representative. When there is no approved State program, and there is an EPA 

administered program, Director means the Regional Administrator. When there is an approved 

State program, “Director” normally means the State Director. 

Discharge Monitoring Report (DMR) - The form used to report self-monitoring results by 

NPDES permittees. DMRs must be used by approved States as well as by EPA. 

Dissolved air flotation (DAF) - A wastewater treatment technology (see Section 8.0). 

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16.0 - Glossary/List of Acronyms 

Economic, Environmental, and Benefits Analysis of the Final Metal Products & Machinery 

Rule (EEBA) - This document (EPA-821-B-03-002) presents the methodology employed to 

assess economic impacts and environmental impacts and benefits of the final rule and the results 

of the analysis. 

Effluent Limitation - Any restriction imposed by the Director on quantities, discharge rates, and 

concentrations of pollutants which are discharged from point sources into waters of the United 

States, the waters of the contiguous zone, or the ocean. 

Effluent Limitations Guidelines (ELG) - A regulation published by the Administrator under 

Section 304(b) of CWA that establishes national technology-based effluent requirements for a 

specific industrial category. 

Emission - Passage of air pollutants into the atmosphere via a gas stream or other means. 

End-of-Pipe Treatment (EOP) - Refers to those processes that treat a facility waste stream for 

pollutant removal prior to discharge. 

EPA - The U.S. Environmental Protection Agency (also referred to as “the Agency”). 

Existing source - For this rule, any facility from which there is or may be a discharge of 

pollutants, the construction of which is commenced before the publication of the MP&M final 

final regulations. 

Facility - A place of business that manufactures, rebuilds, or maintains metal parts, products, or 

machines (also referred to as “site”). See Section 1.0 for the applicability of the MP&M final 

rule. The facility includes all contiguous and noncontiguous property with established boundaries 

owned, operated, leased, or under control of the business entity. The property may be divided by 

public or private right-of-way. 

Federal Register (FR) - This document is published by the U.S. Government Printing Office. A 

publication making available to the public regulations and legal notices issued by federal 

agencies. 

Federally Owned Treatment Works (FOTW) - Any device or system owned and/or operated 

by a U.S. federal agency to recycle, reclaim, or treat liquid sewage or liquid industrial wastes. 

Full Time Equivalents (FTE) - This is related to the number of employees at a given facility. 

Fundamentally Different Factors (FDF) - Those components of a petitioner’s facility that are 

determined to be so unlike those components considered by EPA during development of the 

MP&M final rule that the facility is worthy of a variance (see Section XI.C.1 of the preamble to 

the final rule). 

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16.0 - Glossary/List of Acronyms 

General Metals (GM) Subcategory - As discussed in Section 9.0, EPA proposed, but did not 

promulgate, a separate subcategory for these facilities. 

Grab Sample - A sample which is taken from a wastestream on a one-time basis without 

consideration of the flow rate of the wastestream and without consideration of time. 

Hazardous Air Pollutant (HAP) - Substances listed by EPA as air toxics under Section 112 of 

the Clean Air Act. 

Hazardous Waste - Any material that meets the Resource Conservation and Recovery Act 

definition of “hazardous waste” contained in 40 CFR 261. 

Hexane Extractable Material (HEM) - A method-defined parameter that measures the presence 

of relatively nonvolatile hydrocarbons, vegetable oils, animal fats, waxes, soaps, greases, and 

related material that are extractable in the solvent n-hexane (see Appendix B). 

Indirect Capital Costs - One-time capital costs that are not technology-specific and are 

represented as a multiplication factor that is applied to the direct capital costs estimated in the 

MP&M cost model. 

Indirect Discharge - The introduction of pollutants into a municipal sewage treatment system 

from any nondomestic source (i.e., any industrial or commercial facility) regulated under Section 

307(b), (c), or (d) of the CWA. 

Influent - Wastewater entering a facility wastewater treatment unit. 

Information Collection Request (ICR) - The Paperwork Reduction Act (44 U.S.C. 3501 et 

seq.) stipulates that every federal agency, including EPA, must obtain approval from the Office 

of Management and Budget before collecting the same or similar information from 10 or more 

members of the public. 

Local Limits - Conditional discharge limits imposed by municipalities upon industrial or 

commercial facilities that discharge to the municipal sewage treatment system. 

Long-term average (LTA) - For purposes of the pretreatment standards, average pollutant levels 

achieved over a period of time by a facility, subcategory, or technology option. 

Maximum Achievable Control Technology (MACT) - Air pollution control applicable to 

hazardous air pollutants (HAPs) - see NESHAPS. 

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16.0 - Glossary/List of Acronyms 

Maximum daily discharge limitation - Definitions provided at 40 CFR 122.2 state that the 

"maximum daily discharge limitation" is the "highest allowable ‘daily discharge.' " Daily 

discharge is defined as the "‘discharge of a pollutant' measured during a calendar day or any 

24-hour period that reasonably represents the calendar day for purposes of sampling." Section 

10.0 describes the data selection and calculations used to develop the final rule limitations. 

Metal-bearing operations - One or more of the operations listed in 40 CFR 438.2(d). See also 

Section 1.0. 

Metal Finishing Job Shops (MFJS) Subcategory - As discussed in Section 9.0, EPA proposed, 

but did not promulgate, a separate subcategory for these facilities. 

Metal Products and Machinery (MP&M) - A regulation published by the Administrator under 

Section 304(b) of CWA that establishes national technology-based effluent requirements for the 

Metal Products and Machinery Point Source Category. 

Million gallons per year (MGY) - Unit of effluent discharge. 

Minimum Level - The lowest concentration that can be reliably measured by an analytical 

method. 

Mixed-Use Facility - Any municipal, private, U.S. military or federal facility that contains both 

industrial and commercial/administrative buildings at which one or more industrial sites conduct 

operations within the facility’s boundaries. 

National Emissions Standards for Hazardous Air Pollutants (NESHAPS) - Emissions 

standards set by EPA for an air pollutant that may cause an increase in fatalities or in serious, 

irreversible, or incapacitating illness. 

National Pollutant Discharge Elimination System (NPDES) - The national program for 

issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and 

imposing and enforcing pretreatment requirements, under Sections 307, 318, 402, and 405 of 

CWA. 

New Source - As defined in 40 CFR 122.2 and 122.29, and 403.3(k), a new source is any 

building, structure, facility, or installation from which there is or may be a discharge of 

pollutants, the construction of which commenced for purposes of compliance with New Source 

Performance Standards and Pretreatment Standards for New Sources after the promulgation of 

the final rule under Clean Water Act Sections 306 and 307(c). 

New Source Performance Standards (NSPS) - Technology-based standards for facilities that 

qualify as new sources under 40 CFR §122.2 and 40 CFR §122.29. Standards consider that the 

new source facility has an opportunity to design operations to more effectively control pollutant 

discharges. 

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16.0 - Glossary/List of Acronyms 

Non-Chromium Anodizing (NCA) Subcategory - As discussed in Section 9.0, EPA proposed, 

but did not promulgate, a separate subcategory for these facilities. 

Noncontact Cooling Water - Water used for cooling that does not come into direct contact with 

any raw material, intermediate product, by-product, waste product, or finished product. This 

term is not intended to relate to air conditioning systems. 

Nonconventional Pollutants - All pollutants that are not included in the list of conventional or 

toxic pollutants in 40 CFR 401. Includes pollutants such as chemical oxygen demand (COD), 

total organic carbon (TOC), nitrogen, and phosphorus. 

Nondetect Value - Samples below the level that can be reliable measured by an analytical 

method. This is also known, in statistical terms, as left-censored (i.e., value having an upper 

bound at the sample-specific detection limit and a lower bound at zero). 

Nonprocess Wastewater - Sanitary wastewater, noncontact cooling water, water from 

laundering, and noncontact stormwater. Nonprocess wastewater for this part also includes 

wastewater discharges from nonindustrial sources such as residential housing, schools, churches, 

recreational parks, shopping centers as well as wastewater discharges from gas stations, utility 

plants, and hospitals (see 40 CFR 438.2(e). 

Non-Water Quality Environmental Impact (NWQI) - Deleterious aspects of control and 

treatment technologies applicable to point source category wastes, including, but not limited to 

air pollution, noise, radiation, sludge and solid waste generation, and energy used. 

North American Industry Classification System. (NAICS) - This system is a unique method 

for classifying business establishments. Adopted in 1997 to replace the old Standard Industrial 

Classification (SIC) system, it is the industry classification system used by the statistical agencies 

of the United States. 

Notice of Data Availability (NODA) - This Federal Register notice was published in June 5, 

2002 (67 FR 38752). See Section 2.0. 

NRDC - Natural Resources Defense Council. 

NRMRL - EPA’s National Risk Management Research Laboratory (formerly RREL - EPA’s 

Risk Reduction Engineering Laboratory). 

NSCEP - EPA’s National Service Center for Environmental Publications 

(http://www.epa.gov/ncepi). 

OCPSF - Organic Chemicals, Plastics, and Synthetic Fibers Manufacturing Point Source 

Category (40 CFR 414). 

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16.0 - Glossary/List of Acronyms 

Off Site - Outside the boundary of the facility. 

Oily operations - One or or more of the operations listed in 40 CFR 438.2(f). See also 

Section 1. 

Oily Wastes Subcategory (OWS) - A subcategory (Subpart A) of the Metal Products and 

Machinery Point Source Category (40 CFR 438). 

OMB - U.S. Office of Management and Budget. 

On Site - Within the boundary of the facility. 

Operating and Maintenance (O&M) Costs - Costs related to operating and maintaining a 

treatment system, including the estimated costs for compliance wastewater monitoring of the 

effluent. 

ORP - Oxidation-reduction potential. 

PE - Pound-equivalents (units used to weight toxic pollutants). 

pH - A measure of the hydrogen ion concentration of water or wastewater; expressed as the 

negative log of the hydrogen ion concentration in mg/l. A pH of 7 is neutral. A pH less than 7 is 

acidic, and a pH greater than 7 is basic. 

Point Source - Any discernible, confined, and discrete conveyance, including but not limited to 

any pipe, ditch, channel, tunnel, conduit, well, discrete fixture, container, rolling stock, 

concentrated animal feeding operation, landfill leachate collection system, vessel, or other 

floating craft from which pollutants are or may be discharged. 

Pollutant - Dredged spoil, solid waste, incinerator residue, filter backwash, sewage, garbage, 

sewage sludge, munitions, chemical wastes, biological materials, radioactive materials (except 

those regulated under the Atomic Energy Act of 1954, as amended (42 U.S.C. 2011 et seq.)), 

heat, wrecked or discarded equipment, rock, sand, cellar dirt and industrial, municipal, and 

agricultural waste discharged into water. 

Pollutant of Concern (POC) - EPA evaluated wastewater to determine the presence of priority, 

conventional, and nonconventional pollutant parameters. See Section 7.0 for the criteria EPA 

used to identify pollutants of concern (POCs) and regulated pollutants. 

Pollution Prevention - The use of materials, processes, or practices that reduce or eliminate the 

creation of pollutants or wastes. It includes practices that reduce the use of hazardous and 

nonhazardous materials, energy, water, or other resources, as well as those practices that protect 

natural resources through conservation or more efficient use. Pollution prevention consists of 

source reduction, in-process recycle and reuse, and water conservation practices. 

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16.0 - Glossary/List of Acronyms 

Pollutant Prevention Act of 1990 (PPA) - 42 U.S.C. 13101 et seq., Public Law 101-508, 

November 5, 1990. 

Pretreatment - The reduction of the amount of pollutants, the elimination of pollutants, or the 

alteration of the nature of pollutant properties in wastewater prior to or in lieu of discharging or 

otherwise introducing such pollutants into a publicly owned treatment works. 

Pretreatment standards for existing sources (PSES) - PSES are designed to prevent the 

discharge of pollutants that pass through, interfere with, or are otherwise incompatible with the 

operation of publicly-owned treatment works (POTWs), including sludge disposal methods at 

POTWs. Pretreatment standards for existing sources are technology-based and are analogous to 

BAT effluent limitations guidelines. 

Pretreatment standards for New sources (PSNS) - Like PSES, PSNS are designed to prevent 

the discharges of pollutants that pass through, interfere with, or are otherwise incompatible with 

the operation of POTWs. PSNS are to be issued at the same time as NSPS. New indirect 

dischargers have the opportunity to incorporate into their plants the best available demonstrated 

technologies. The Agency considers the same factors in promulgating PSNS as it considers in 

promulgating NSPS. 

Printed Wiring Board (PWB) Subcategory - As discussed in Section 9.0, EPA proposed, but 

did not promulgate, a separate subcategory for these facilities. 

Priority Pollutants - The 126 pollutants listed in 40 CFR 423, Appendix A. 

Privately Owned Treatment Works (PrOTW) - Any device or system owned and operated by 

a private company that is used to recycle, reclaim, or treat liquid industrial wastes not generated 

by that company. 

Process Wastewater - Wastewater as defined at 40 CFR 122 and 401, and includes wastewater 

from noncontact, nondestructive testing (e.g., photographic wastewater from nondestructive 

X-ray examination of parts) performed at facilities subject to this part and includes wastewater 

from air pollution control devices (see 40 CFR 438.2). 

Production-Normalized Flow (PNF) - Volume of wastewater generated per unit of production. 

Publicly Owned Treatment Works (POTW) - A treatment works, as defined by Section 212 of 

the CWA, that is owned by the State or municipality. This definition includes any devices and 

systems used in the storage, treatment, recycling, and reclamation of municipal sewage or 

industrial wastes of a liquid nature. It also includes sewers, pipes, and other conveyances only if 

they convey wastewater to a POTW treatment plant. 

Railroad Line Maintenance (RRLM) Subcategory - As discussed in Section 9.0, EPA 

proposed, but did not promulgate, a separate subcategory for these facilities. 

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16.0 - Glossary/List of Acronyms 

Resource Conservation and Recovery Act of 1976 (RCRA) - This law (42 U.S.C. Section 

6901 et seq.) regulates the generation, treatment, storage, disposal, or recycling of solid and 

hazardous wastes. 

SBA - U.S. Small Business Administration. 

Self-Monitoring - Sampling and analyses performed by a facility to determine compliance with a 

permit or other regulatory requirements. 

Semivolatile Organic Compound (SVOC) - A measure of semivolatile organic constituents 

performed by isotope dilution gas chromatography/mass spectrometry (GC/MS), EPA Method 

1625. 

SGP - EPA’s National Metal Finishing Strategic Goals Program. 

Shipbuilding Dry Dock (SDD) Subcategory - As discussed in Section 9.0, EPA proposed, but 

did not promulgate, a separate subcategory for these facilities. 

SIC - Standard Industrial Classification, a numerical categorization scheme used by the U.S. 

Department of Commerce to catalog economic activity according to product type. 

Significant Industrial User (SIU) - An indirect discharger that is the focus of control efforts 

under the national pretreatment program; includes all indirect dischargers subject to national 

categorical pretreatment standards, and all other indirect dischargers that contribute 25,000 gpd 

or more of process wastewater, or which make up five percent or more of the hydraulic 

or organic loading to the municipal treatment plant, subject to certain exceptions. 

Silica Gel Treated Hexane Extractable Material (SGT-HEM) - A method-defined parameter 

that measures the presence of mineral oils that are extractable in the solvent n-hexane and not 

absorbed by silica gel (see Appendix B). 

Site - See “Facility.” 

Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA) - Public Law 104-

121, March 29, 1996. 

Source Reduction - Any practice that reduces the amount of any hazardous substance, pollutant, 

or contaminant entering any waste stream or otherwise being released into the environment prior 

to recycling, treatment, or disposal. Source reduction can include equipment or technology 

modifications, process or procedure modifications, substitution of raw materials, and 

improvements in housekeeping, maintenance, training, or inventory control. 

Steel Forming and Finishing (SFF) Subcategory - As discussed in Section 9.0, EPA proposed, 

but did not promulgate, a separate subcategory for these facilities. 

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16.0 - Glossary/List of Acronyms 

Stormwater - Stormwater runoff, snow melt runoff, and surface runoff and drainage (see 40 

CFR §122.26(b)(13)). 

Surface Water - Waters of the United States, as defined at 40 CFR 122.2. 

Technical Development Document (TDD) - Development Document for the Final Effluent 

Limitations Guidelines and Standards for the Metal Products & Machinery Point Source 

Category (EPA-821-B-03-001). 

Technology in Place (TIP) - Refers to those technologies that the Agency considered to be 

installed and operating at a model site. 

Technology-Based Effluent Limit - A permit limit for a pollutant that is based on the capability 

of a treatment method to reduce the pollutant to a certain concentration. 

Total Annualized Cost (TAC) - Cost calculated from the capital and annual costs assuming a 

7-percent discount rate over an estimated 15-year equipment life. 

Total Capital Investment (TCI) - Total one-time capital costs required to build a treatment 

system (i.e., sum of direct and indirect capital costs). 

Total Kjeldahl nitrogen (TKN) - Measure of reduced forms of nitrogen (see Appendix B). 

Total Maximum Daily Load (TMDL) - The amount of pollutant, or property of a pollutant, 

from point, nonpoint, and natural background sources, that may be discharged to a water 

quality-limited receiving water. Any pollutant loading above the TMDL results in violation of 

applicable water quality standards. 

Total Organic Carbon (TOC) - A nonconventional bulk parameter that measures the total 

organic content of wastewater (see Appendix B). 

Total Organics Parameter (TOP) - Measure of toxic organics developed for the MP&M 

proposed rule. EPA developed a list of organic pollutants, called the Total Organics Parameter 

(TOP), using the list of organic priority pollutants and other nonconventional organic pollutants 

that met EPA’s POCs criteria for the MP&M rule. Of the nonconventional organic chemicals on 

the MP&M POCs list, EPA included only those that were removed in appreciable quantities by 

the selected technology option (based on toxic weighted pound-equivalents) in two or more 

subcategories. The TOP list is comprised of all of the priority and nonconventional organic 

pollutants listed in Table 16-1. 

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16.0 - Glossary/List of Acronyms 

Table 16-1 

Priority and Nonconventional Organic Pollutants Comprising the Total 

Organics Parameter 

Priority Organic Pollutants 

1,1,1-Trichloroethane Di-n-Butyl Phthalate 

1,1-Dichloroethane Di-n-Octyl Phthalate 

1,1-Dichloroethylene Dimethyl Phthalate 

2,4-Dimethylphenol Ethylbenzene 

2,4-Dinitrophenol Fluoranthene 

2,6-Dinitrotoluene Fluorene 

2-Nitrophenol Isophorone 

4-Chloro-m-cresol Methylene Chloride 

4-Nitrophenol n-Nitrosodimethylamine 

Acenaphthene n-Nitrosodiphenylamine 

Acrolein Naphthalene 

Anthracene Phenanthrene 

Benzyl Butyl Phthalate Phenol 

Bis(2-Ethylhexyl) Phthalate Pyrene 

Chlorobenzene Tetrachloroethene 

Chloroethane Toluene 

Chloroform Trichloroethylene 

1-Methylfluorene Biphenyl 

1-Methylphenanthrene Carbon Disulfide 

2-Isopropylnaphthalene Dibenzofuran 

2-Methylnaphthalene Dibenzothiophene 

Nonconventional Organic Pollutants 

3,6-Dimethylphenanthrene n-Hexadecane 

Aniline n-Tetradecane 

Benzoic Acid p-Cymene 

Total Petroleum Hydrocarbons (TPH) - A method-defined parameter that measures the 

presence of mineral oils that are extractable in Freon 113 (1,1,2-trichloro-1,2,2-trifluoroethane) 

and not absorbed by silica gel (see Appendix B). 

Total Suspended Solids (TSS) - A measure of the filterable solids present in a sample, as 

determined by the method specified in 40 CFR 136. (see Appendix B). 

Total Toxic Organics (TTO) - A parameter that is the summation of all quantifiable values 

greater than 0.01 milligrams per liter for the toxic organics (see 40 CFR 433.11(e)). 

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16.0 - Glossary/List of Acronyms 

Toxic Release Inventory (TRI) - Database of toxic releases in the United States. 

Toxic Substances Control Act (TSCA) - 15 U.S.C. 2601 et seq. 

Toxic weighting factor (TWF) - A factor developed for various pollutants using a combination 

of toxicity data on human health and aquatic life and relative to the toxicity of copper. EPA uses 

toxic weighting factors in determining the amount of toxicity that a pollutant may exert on 

human health and aquatic life. 

Treatment - Any method, technique, or process designed to change the physical, chemical, or 

biological character or composition of any metal-bearing, oily, or organic waste so as to 

neutralize such wastes, to render such wastes amenable to discharge, or to recover metal, oil, or 

organic content from the wastes. 

Treatment Effectiveness Concentration - Treated effluent pollutant concentration that can be 

achieved by each treatment technology that is part of an MP&M regulatory option. 

Treatment, Storage, and Disposal Facility (TSDF) - A facility that treats, stores, or disposes of 

hazardous waste in compliance with the applicable standards and permit requirements set forth 

in 40 CFR 264, 265, 266, and 270. 

Treatment Works Treating Domestic Sewage (TWTDS) - Includes all POTWs and other 

facilities that treat domestic wastewater, and facilities that do not treat domestic wastewater, but 

that treat or dispose of sewage sludge. 

Unit Operations - All processes performed on metal parts, products, or machines in their 

manufacture, maintenance, or rebuilding. 

Upset - An exceptional incident in which there is unintentional and temporary noncompliance 

with the permit limit because of factors beyond the reasonable control of the permittee. An upset 

does not include noncompliance to the extent caused by operational error, improperly designed 

treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or 

improper operation. 

U.S.C. - The United States Code. 

Variability factor - Used in calculating a limitation (or standard) to allow for reasonable 

variation in pollutant concentrations when processed through extensively and well designed 

Volatile Organic Compound (VOC) - A measure of volatile organic constituents performed by 

isotope dilution gas chromatography/mass spectrometry (GC/MS) (see Appendix B). 

Wet Air Pollution or Odor Pollution Control System Scrubbers - Any equipment using water 

or water mixtures to control emissions of dust, odors, volatiles, sprays, or other pollutants. 

16-13

16.0 - Glossary/List of Acronyms 

Zero discharger - A facility that does not discharge pollutants to waters of the United States or 

to a POTW. Included in this definition are discharge or disposal of pollutants by way of 

evaporation, deep-well injection, off-site transfer to a treatment facility, and land application. 

16-14

Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Appendix A

EXAMPLE NAICS AND SIC CODES FOR THE 

METAL PRODUCTS & MACHINERY FINAL 

EFFLUENT LIMITATIONS GUIDELINES AND STANDARDS
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Appendix A

Example NAICS and SIC codes for the 

Metal Products & Machinery Final

Effluent Limitations Guidelines and Standards

The scope of the MP&M regulation includes facilities that discharge process 

wastewater from oily operations and manufacture, maintain, or rebuild metal parts, products, or 

machines used in the following sectors: Aerospace, Aircraft, Bus & Truck, Electronic Equipment, 

Hardware, Household Equipment, Instruments, Mobile Industrial Equipment, Motor Vehicles, Office 

Machines, Ordnance, Precious Metals and Jewelry, Railroad, Ships and Boats, Stationary Industrial 

Equipment, and Miscellaneous Metal Products. In addition, state, local and federal government 

facilities that discharge wastewater from oily operations and manufacture, maintain, or rebuild metal 

parts, products or machines (e.g., a town that operates its own bus, truck, and/or snow removal 

equipment maintenance facility) are also covered by the MP&M rule. 

EPA also evaluated job shops and printed wiring board facilities for the final rule (see 

Section 6.0). As described in Section 9.0, these facilities are not regulated by the MP&M effluent 

guidelines. 

Table A-1 lists of example Standard Industrial Classification (SIC) codes and North 

American Industrial Classification System (NAICS) codes associated with the various MP&M 

industrial sectors and the two industrial sectors also reviewed for the final rule. Please note that this list 

is not intended to be exhaustive, but rather it provides a guide regarding entities that may be within the 

scope of the MP&M industry. 

Table A-1 

Example SIC and NAICS Codes Associated with MP&M Industrial Sectors 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Aerospace 

33641400 3761 Guided Missiles and Space Vehicles 

33641500 3764 Guided Missile and Space Vehicle Propulsion 

33641900 3769 Other Space Vehicle and Missile Parts 

A-1
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Aircraft 

33641100 3721 Aircraft 

33641200 3724 Aircraft Engines and Engine Parts 

33641300 

33291220 

33399520 

33399620 

3728 Aircraft Parts and Auxiliary Equipment 

48811110 

48811910 

48819000 

56172020 

4581 Airports, Flying Fields, Airport Terminal Services 

Bus And Truck 

33621120 3713 Truck and Bus Bodies 

33621200 3715 Truck Trailers 

48511100 

48511200 

48511300 

48511900 

4111 Local and Suburban Transit 

48532000 

48541020 

48599100 

48599920 

62191090 

4119 Local Passenger Transit, N.E.C. 

48521000 4131 Intercity and Rural Bus Transportation 

48551010 4141 Local Bus Charter Service 

48551020 4142 Bus Charter Service, Except Local 

48849010 4173 Bus Terminal and Service Facilities 

48411010 

48411020 

4212 Local Trucking without Storage 

48412100 

48412200 

48421020 

4213 Trucking, Except Local 

48411030 

48411040 

4214 Local Trucking with Storage 

A-2
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Bus and Truck (Continued) 

49211010 

49221000 

4215 Courier Services, Except by Air 

48849020 4231 Trucking Terminal Facilities 

Electronic Equipment 

33421000 3661 Telephone and Telegraph Apparatus 

33422010 3663 Radio and Television Broadcast and Communications Equipment 

33429000 3669 Communications Equipment, N.E.C. 

33441100 3671 Electron Tubes 

33441400 3675 Electronic Capacitors 

33441610 

33441620 

3677 Electronic Coils and Transformers 

33441700 3678 Connectors for Electronic Applications 

33422020 

33441820 

33441900 

33632210 

3679 Electronic Components, N.E.C. 

33451010 

33451110 

33451610 

33451910 

33512920 

33599920 

33911410 

3699 Electrical Machinery, Equipment, and Supplies, N.E.C. 

Hardware 

32312220 2796 Platemaking and Related Services 

33281100 3398 Metal Heat Treating 

33243910 3412 Metal Shipping Barrels, Drums, Kegs, Pails 

33221110 3421 Cutlery 

33221210 

33221240 

3423 Hand and Edge Tools, Except Machine Tools and Handsaws 

33221300 3425 Hand Saws and Saw Blades 

33243920 3429 Hardware, N.E.C. 

A-3
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Hardware (Continued) 

33341410 3433 Heating Equipment, Except Electric and Warm Air Furnace 

33231210 3441 Fabricated Structural Metal 

33231300 3443 Fabricated Plate Work (Boiler Shops) 

33243930 3444 Sheet Metal Work 

33232310 3446 Architectural and Ornamental Metal Work 

33231100 3448 Prefabricated Metal Buildings and Components 

33231220 3449 Miscellaneous Metal Work 

33272100 3451 Screw Machine Products 

33272200 3452 Bolts, Nuts, Screws, Rivets, and Washers 

33211100 3462 Iron and Steel Forgings 

33211500 3466 Crowns and Closures 

33221400 3469 Metal Stamping, N.E.C. 

33291210 3492 Fluid Power Valves and Hose Fittings 

33261100 3493 Steel Springs 

33291920 3494 Valves and Pipe Fittings, Except Brass 

33451810 3495 Wire Springs 

33261830 3496 Miscellaneous Fabricated Wire Products 

33299620 3498 Fabricated Pipe and Fabricated Pipe Fitting 

33243940 

33251020 

33211700 

33721540 

33991420 

3499 Fabricated Metal Products, N.E.C. 

33351210 3541 Machine Tools, Metal Cutting Types 

33351300 3542 Machine Tools, Metal Forming Types 

33351400 3544 Special Dies and Tools, Die Sets, Jigs and Fixtures, and Industrial Molds 

33351500 3545 Machine Tool Access and Measuring Devices 

33399100 3546 Power Driven Hand Tools 

33999320 3965 Fasteners, Buttons, Needles, Pins 

A-4
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Household Equipment 

33712400 2514 Metal Household Furniture 

33721400 2522 Office Furniture, Except Wood 

33712710 2531 Public Building and Related Furniture 

33721530 2542 Partitions and Fixtures, Except Wood 

33792000 2591 Drapery Hardware and Window Blinds/shades 

33712720 

33911310 

2599 Furniture and Fixtures, N.E.C. 

33299800 3431 Metal Sanitary Ware 

33291300 3432 Plumbing Fittings and Brass Goods 

33232120 3442 Metal Doors, Sash, and Trim 

33522100 3631 Household Cooking Equipment 

33522200 3632 Household Refrigerators and Home and Farm and Freezers 

33522400 3633 Household Laundry Equipment 

33521100 

33341420 

3634 Electric Housewares and Fans 

33521210 3635 Household Vacuum Cleaners 

33521220 

33522800 

3639 Household Appliances, N.E.C. 

33511000 3641 Electric Lamps 

33593100 3643 Current-Carrying Wiring Devices 

33593200 3644 Noncurrent-Carrying Wiring Devices 

33512120 3645 Residential Electrical Lighting Fixtures 

33512200 3646 Commercial, Industrial, and Institutional 

33512910 3648 Lighting Equipment, NEC 

33431000 3651 Radio/Television Sets Except Communication Types 

81131030 

81141220 

7623 Refrigeration and Air-conditioning Service and Repair Shops 

A-5
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Instruments 

33451120 3812 Search, Detection, Navigation, Guidance, Aeronautical, Nautical Systems and 

Instruments 

33911100 3821 Laboratory Apparatus and Furniture 

33451200 3822 Automatic Environmental Controls 

33451300 3823 Process Control Instruments 

33451400 3824 Fluid Meters and Counting Devices 

33451500 3825 Instruments to Measure Electricity 

33451620 3826 Laboratory Analytical Instruments 

33331420 3827 Optical Instruments and Lenses 

33451920 3829 Measuring and Controlling Devices, N.E.C. 

33911210 

33911220 

3841 Surgical and Medical Instruments and Apparatus 

32229120 

33451020 

33911320 

3842 Orthopedic, Prosthetic and Surgical Supplies 

33911420 3843 Dental Equipment and Supplies 

33451700 3844 X-ray Apparatus and Tubes 

33451030 3845 Electromedical Equipment 

33911500 3851 Ophthalmic Goods 

81121210 

81121310 

81121910 

81141120 

81141210 

7629 Electric Repair Shop 

Job Shopsa 

33281300 3471 Plating and Polishing 

33281200 

33991210 

33991410 

3479 Metal Coating and Allied Services 

A-6
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Mobile Industrial Equipment 

33221220 

33311100 

33392210 

3523 Farm Machinery and Equipment 

33221230 

33311200 

3524 Garden Tractors and Lawn and Garden Equipment 

33312000 

33392310 

33651010 

3531 Construction Machinery and Equipment 

33313100 3532 Mining Machinery and Equipment, Except Oil Field 

33392320 3536 Hoists, Industrial Cranes and Monorails 

33243950 

33299960 

33392400 

3537 Industrial Trucks, Tractors, Trailers 

33699220 3795 Tanks and Tank Components 

Motor Vehicle 

33637000 3465 Automotive Stampings 

33631100 3592 Carburetors, Piston Rings, Valves 

33632100 3647 Vehicular Lighting Equipment 

33632220 3694 Electrical Equipment for Motor Vehicles 

33611100 

33611200 

33612000 

33621110 

33621130 

33699210 

3711 Motor Vehicle and Automobile Bodies 

33621130 3714 Motor Vehicle Parts and Accessories 

33621300 3716 Mobile Homes 

33699110 3751 Motorcycles 

33621410 3792 Travel Trailers and Campers 

33699900 3799 Miscellaneous Transportation Equipment 

48531000 4121 Taxicabs 

44131030 5013 Motor Vehicle Supplies and New Parts 

A-7
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Motor Vehicle (Continued) 

44111000 5511 Motor Vehicle Dealers (New and Used) 

44112000 5521 Motor Vehicle Dealers (Used Only) 

44121000 5561 Recreational Vehicle Dealers 

44122100 5571 Motorcycle Dealers 

44122900 5599 Automotive Dealers, N.E.C. 

53211200 7515 Passenger Car Lease 

81112110 

81112120 

81112130 

7532 Top, Body, and Upholstery Repair and Paint Shops 

81111200 7533 Auto Exhaust Systems 

81111300 7537 Auto Transmission Repair 

81111100 7538 General Automotive Repair 

81111810 

81111820 

81111830 

81111840 

81111890 

7539 Auto Repair Shop, N.E.C. 

81119100 

81119820 

7549 Auto Services, Except Repair and Carwashes 

Office Machines 

33411100 3571 Electronic Computers 

33411200 3572 Typewriters 

33411300 3575 Computer Terminals 

33411910 3577 Computer Peripheral Equipment, N.E.C. 

33411920 3578 Calculating, Accounting Machines Except Computers 

33451820 3579 Office Machines, N.E.C. 

81121230 7378 Computer Maintenance and Repairs 

54151220 

54151910 

33451820 

7379 Computer Related Services, N.E.C. 

A-8
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Ordnance 

33299200 3482 Small Arms Ammunition 

33299300 3483 Ammunition, Except for Small Arms 

33299400 3484 Small Arms 

33299500 3489 Ordnance and Accessories, N.E.C. 

Precious Metals and Jewelry 

33451830 3873 Watches, Clocks, and Watchcases 

33991120 3911 Jewelry, Precious Metal 

33991220 3914 Silverware, Plated Ware and Stainless 

33991300 3915 Jewelers' Materials and Lapidary Work 

33991430 3961 Costume Jewelry 

81149010 7631 Watch, Clock, Jewelry Repair 

Printed Circuit Boardsa 

33441200 3672 Printed Circuit Boards 

Railroad 

33391120 

33651020 

3743 Railcars, Railway Systems 

48211100 4011 Railroad Transportation 

48211200 4013 Railroad Transportation 

Ships and Boats 

33661100 3731 Ship Building and Repairing 

33661200 

81149020 

3732 Boat Building and Repairing 

48311100 4412 Deep Sea Foreign Transportation 

48311310 4424 Deep Sea Domestic Transportation 

48311320 4432 Freight Transportation Great Lakes 

48321110 4449 Water Transportation of Freight, N.E.C. 

48311410 4481 Deep Sea Passenger Transportation 

48311420 4482 Ferries 

A-9
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Ships and Boats (Continued) 

48321220 

48721010 

4489 Water Passenger Transportation, N.E.C. 

48831010 4491 Marine Cargo Handling 

48321120 4492 Towing and Tugboat Service 

71393000 4493 Marinas 

48831020 

48833020 

48833030 

48839010 

53241110 

4499 Water Transportation Services, N.E.C. 

Stationary Industrial Equipment 

33361100 3511 Steam, Gas, Hydraulic Turbines, Generating Units 

33639910 3519 Internal Combustion Engines, N.E.C. 

33313200 3533 Oil Field Machinery and Equipment 

33392100 3534 Elevators and Moving Stairways 

33392220 3535 Conveyors and Conveying Equipment 

33299700 3543 Industrial Patterns 

33351600 3547 Rolling Mill Machinery and Equipment 

33399210 3548 Electric and Gas Welding and Soldering 

33351800 3549 Metal Working Machinery, N.E.C. 

33329210 3552 Textile Machinery 

33321000 3553 Woodworking Machinery 

33329100 3554 Paper Industries Machinery 

33329310 3555 Printing Trades Machinery and Equipment 

33329400 3556 Food Products Machinery 

33329810 3559 Special Industry Machinery, N.E.C. 

33391110 3561 Pumps and Pumping Equipment 

33299100 3562 Ball and Roller Bearings 

33391200 3563 Air and Gas Compressors 

A-10
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Stationary Industrial Equipment (Continued) 

33341200 

33341100 

3564 Blowers and Exhaust and Ventilation Fans 

33399300 3565 Industrial Patterns 

33361200 3566 Speed Changers, High Speed Drivers and Gears 

33399400 3567 Industrial Process Furnaces and Ovens 

33361300 3568 Mechanical Power Transmission Equipment, N.E.C. 

33399910 3569 General Industrial Machinery, N.E.C. 

33331100 3581 Automatic Merchandising Machines 

33331200 3582 Commercial Laundry Equipment 

33639100 3585 Refrigeration and Air and Heating Equipment 

33391300 3586 Measuring and Dispensing Pumps 

33331920 3589 Service Industry Machines, N.E.C. 

33399510 3593 Fluid Power Cylinders and Actuators 

33399610 3594 Fluid Power Pumps and Motors 

33399700 3596 Scales and Balances, Except Laboratory 

33399920 3599 Machinery, Except Electrical, N.E.C. 

33531120 3612 Transformers 

33531300 3613 Switchgear and Switchboard Apparatus 

33531210 3621 Motors and Generators 

33599910 3629 Electric Industrial Apparatus, N.E.C. 

53241210 7353 Heavy Construction Equipment Rental, Leasing 

53221000 

53229990 

53231000 

53241190 

53241290 

53242010 

53249020 

56299120 

7359 Equipment Rental, Leasing, N.E.C. 

A-11
Appendix A - Example NAICS & SIC codes for MP&M Sectors 

Table A-1 (Continued) 

Example NAICS and SIC Codes for the MP&M Industrial Sectors 

NAICS 

Code SIC Code Standard Industrial Classification Groups 

Miscellaneous Metal Products 

33299940 3497 Metal Foil and Leaf 

33331520 3861 Photographic Equipment and Supplies 

33999200 3931 Musical Instruments 

33699120 3944 Games, Toys, Children's Vehicles 

33992000 3949 Sporting and Athletic Goods, N.E.C. 

33994100 3951 Pens and Mechanical Pencils 

33994300 3953 Marking Devices 

33995000 3993 Signs and Advertising Displays 

33999500 3995 Burial Caskets 

33221270 

33299980 

33512130 

3999 Manufacturing Industries, N.E.C. 

81149030 7692 Welding Repair 

48839030 

81149090 

56162200 

56179010 

81121220 

81121990 

81131010 

81141110 

81141290 

7699 Repair Shop, Related Service 

Continuous Electroplaters 

33281300 3399 Electroplating, Plating, Polishing, Anodizing, and Coloring 

Source: U.S. Census Bureau, North American Industrial Classification System,

http://www.census.gov/epcd/www/naics.html.

N.E.C. - Not elsewhere classified.

a

Industrial sector considered, but not included, in Part 438.

A-12
Appendix B - Analytical Methods and Baseline Values 

Appendix B

ANALYTICAL METHODS AND BASELINE VALUES

FOR THE METAL PRODUCTS AND MACHINERY INDUSTRY
Appendix B - Analytical Methods and Baseline Values 

APPENDIX B 

ANALYTICAL METHODS AND BASELINE VALUES 

B.1 Nominal Quantitation Limits

B.2 Baseline Values

B.3 Analytical Results Reporting Conventions

B.4 Analytical Methods

B.4.1 EPA Methods 1624, 1625, 1664, and OIA-1677 (Volatile Organics,

Semivolatile Organics, SGT-HEM, HEM, and Available Cyanide)

B.4.2 EPA Methods 1620 and 200.7 (Metals)

B.4.3 EPA Method 335.1 (Amenable Cyanide)

B.4.4 EPA Methods 350.2 and 350.3 (Ammonia as Nitrogen)

B.4.5 EPA Method 405.1 and SM 5210B (BOD5 and Carbonaceous BOD)

B.4.6 EPA Methods 410.1, 410.2, and 410.4 (Chemical Oxygen Demand)

B.4.7 EPA Method 325.3 (Chloride)

B.4.8 EPA Method 340.2 (Fluoride)

B.4.9 EPA Method 218.4, SM 3111A, and SM 3500D (Hexavalent Chromium) 

B.4.10 EPA Method 150.1 and SM 4500H (pH)

B.4.11 EPA Methods 375.2 and 375.4 (Sulfate)

B.4.12 EPA Methods 335.2 and 335.3 (Total Cyanide)

B.4.13 EPA Method 160.1 and SM 2540C (Total Dissolved Solids)

B.4.14 EPA Method 351.3 (Total Kjeldahl Nitrogen)

B.4.15 EPA Method 415.1 (Total Organic Carbon)

B.4.16 EPA Methods 420.1 and 420.2 (Total Phenols)

B.4.17 EPA Methods 365.2 and 365.3 (Total Phosphorus)

B.4.18 EPA Methods 376.1 and 376.2, SM 4500D and SM 4500E, and D4658

(Total Sulfide) 

B.4.19 EPA Method 160.2 and SM 2540D (Total Suspended Solids)

B.4.20 EPA Methods 204.1 and 7041 (Antimony)

B.4.21 EPA Methods 206.2 and 7060A (Arsenic)

B.4.22 EPA Method 231.2 (Gold)

B.4.23 EPA Method 239.1 (Lead)

B.4.24 EPA Methods 245.1 and 245.2 (Mercury)

B.4.25 EPA Method 265.2 (Rhodium)

B.4.26 EPA Methods 270.2 and 7740 (Selenium)

B.4.27 EPA Method 272.1 (Silver)

B.4.28 EPA Methods 279.1 and 7841 (Thallium)

B.4.29 EPA Methods 624 and 625 (Volatile Organics and Semivolatile Organics)

B.4.30 EPA Method 630.1 (Ziram)

B.5 Analytical Method Development Efforts

i 
Appendix B - Analytical Methods and Baseline Values 

The analytical methods described in this appendix were used to determine pollutant 

levels in wastewater samples collected by EPA and industry at a number of metal products and 

machinery facilities. (Sampling efforts are described in Section 3.0) In developing the rule, EPA used 

data from samples collected by EPA and industry to determine the levels of amenable cyanide, 

ammonia as nitrogen, available cyanide, biochemical oxygen demand (BOD), carbonaceous 

biochemical oxygen demand, chemical oxygen demand (COD), chloride, fluoride, hexavalent 

chromium, metals, oil and grease (measured as hexane extractable material (HEM)), pH, semivolatile 

organics, silica gel-treated hexane extractable material (SGT-HEM), sulfate, total cyanide, total 

dissolved solids (TDS), total Kjeldahl nitrogen (TKN), total organic carbon (TOC), total phenols, total 

phosphorus, total sulfide, total suspended solids (TSS), volatile organics, and ziram. As explained in 

Section 7.0, EPA is regulating a subset of these pollutants. 

Sections B.1 and B.2 of this appendix provide explanations of nominal quantitation 

limits and baseline values. Section B.3 describes the reporting conventions used by laboratories in 

expressing the results of the analyses. Section B.4 describes each analytical method and the 

corresponding baseline values that EPA used in determining the pollutants of concern. Section B.5 

discusses analytical method development efforts. Table B-1 identifies the analytical methods and 

baseline values for each pollutant, identifies each pollutant by Chemical Abstract Service Registry 

Number, indicates whether the samples were collected by EPA and/or by industry, and lists the nominal 

quantitation value for the method used. 

Nominal Quantitation Limits 

The nominal quantitation limit is the smallest quantity of an analyte that can be reliably 

measured with a particular method, using the typical (nominal) sample size. The protocols used for 

determination of nominal quantitation limits in a particular method depend on the definitions and 

conventions that EPA used at the time the method was developed. The nominal quantitation limits 

associated with the methods addressed in this section fall into three categories. 

1) The first category pertains to EPA Methods 1624, 1625, 1664, and OIA-1677, which 

define the minimum level (ML) as the lowest level at which the entire analytical system 

must give a recognizable signal and an acceptable calibration point for the analyte. 

These methods are described in Section B.4.1. 

2) The second category pertains specifically to EPA Method 1620, and is explained in 

detail in Section B.4.2. 

3) The third category pertains to the remainder of the chemical methods in which a variety 

of terms are used to describe the lowest level at which measurement results are 

quantitated. In some cases (especially with the classical wet chemistry analytes) the 

methods date to the 1970s and 1980s when different concepts of quantitation were 

employed by EPA. These methods typically list a measurement range or lower limit of 

B-1

B.1 
Appendix B - Analytical Methods and Baseline Values 

measurement. The terms differ by method and, as discussed in subsequent sections, the 

levels presented are not always representative of the lowest levels laboratories currently 

can achieve. 

For those methods associated with a calibration procedure, the laboratories 

demonstrated through a low-point calibration standard that they were capable of 

reliable quantitation at method-specified (or lower) levels. In such cases these nominal 

quantitation limits are operationally equivalent to the ML (though not specifically 

identified as such in the methods). 

In the case of titrimetric or gravimetric methods, the laboratory adhered to the 

established lower limit of the measurement range published in the methods. Details of 

the specific methods are presented in Sections B.4.3 through B.4.30. 

Baseline Values 

As described further in Section 7.0, in determining the pollutants of concern, EPA 

compared the reported concentrations for each pollutant to a multiple of the baseline value. As 

described in Section B.3 and shown in Table B-1, for most pollutants, the baseline value was set equal 

to the nominal quantitation limit for the analytical method. EPA made two general types of exceptions 

which are briefly described below. Section B.4 provides additional details about these exceptions in 

the context of the analytical methods. 

The first type of exception was for baseline values that were different than the nominal 

quantitation limits in the analytical methods. When the baseline values were lower, EPA made these 

exceptions because the laboratory submitted data that demonstrated that reliable measurements could 

be obtained at lower levels for those pollutants. When the baseline values were higher, EPA concluded 

that the nominal quantitation limit for a specified method was less than the level that laboratories could 

reliably achieve and adjusted the baseline value upward. 

The second type of exception was for baseline values set at a common value for 

multiple analytical methods for the same pollutant. For some analytes, EPA permitted the laboratories 

to choose between methods to accommodate sample characteristics and/or industry used a different 

analytical method than EPA. When these methods had different nominal quantitation limits, EPA 

generally used the one with the lowest value or the one associated with the method used for most 

samples. 

B-2

B.2 
Appendix B - Analytical Methods and Baseline Values 

B.3 Analytical Results Reporting Conventions 

The laboratories reported each analytical result either as a numeric value or as not 

quantitated1. A numeric result indicates that the pollutant was quantitated2 in the sample. Most 

analytical results were reported as liquid concentrations in weight/volume units (e.g., micrograms per 

liter (μg/L)), except for the pH data, which were reported in "standard units" (SU). For solid samples, 

the results were provided in weight/weight units (e.g., milligrams per kilogram (mg/kg)). In those 

instances, EPA converted the solids results into weight/volume units by using a conversion factor based 

on the percentage of solids in the samples. 

For example, the result for a hypothetical pollutant X would be reported as "15 g/L" 

when the laboratory cannot quantitated the amount of pollutant X in the sample as being 15 g/L. When 

the laboratory cannot quantitate the amount of pollutant X in the sample, the laboratory would report 

that the analytical result indicated a value less than the sample-specific quantitation limit of 10 g/L (i.e., 

"<10 g/L"). The actual amount of pollutant X in that sample is between zero (i.e., the pollutant is not 

present) and 10 g/L. The sample-specific quantitation limit for a particular pollutant is generally the 

smallest quantity in the calibration range that can be measured reliably in any given sample. Reporting a 

pollutant as nonquantitated does not mean that the pollutant is not present in the wastewater; it merely 

indicates that analytical techniques (whether because of instrument limitations, pollutant interactions, or 

other reasons) do not permit its measurement at levels below the sample-specific quantitation limit. 

In its calculations, EPA generally substituted the reported sample-specific quantitation 

limit for each nonquantitated result. As described in Section B.4.1, EPA substituted the baseline value 

for the nonquantitated result when the sample-specific quantitation limit was less than the baseline value. 

In addition, when the detected quantitated value was below the baseline value, EPA substituted the 

baseline value for the measured value and considered these values to be nonquantitated in the statistical 

analyses. 

B.4 Analytical Methods 

EPA and industry analyzed all metal products and machinery facility wastewater 

samples using methods identified in Table B-1. (As explained in Section 7.0, EPA is regulating only a 

subset of these analytes.) In analyzing samples, EPA generally used analytical methods approved at 40 

CFR 136 or methods that EPA has used for decades in support of effluent guidelines development. 

Exceptions for use of nonapproved methods are explained in the method-specific subsections that 

1

Elsewhere in this document and in the preamble to the rule, EPA may refer to pollutants as “not detected” or 

“nondetected.” This appendix uses the terms “not quantitated” or “nonquantitated” rather than not detected or 

nondetected. 

2

Elsewhere in this document and in the preamble to the rule, EPA may refer to pollutants as “detected.” This 

appendix uses the term “quantitated” rather than detected. 

B-3 
Appendix B - Analytical Methods and Baseline Values 

follow. EPA proposed limitations or standards based only upon data generated by methods approved 

in 40 CFR 136. Table B-1 provides a summary of the analytical methods, the associated pollutants 

measured by the method, the nominal quantitation levels, and the baseline levels. The following sections 

provide additional information supporting the summary in Table B-1. 

The following sections describe the methods used to determine pollutant levels in 

wastewater samples collected at metal products and machinery facilities. Each section states whether 

the method is approved at 40 CFR 136 (even if the pollutant was not proposed to be regulated), 

provides a short description of the method, identifies the nominal quantitation limit, and explains EPA's 

choice for the baseline value. 

B.4.1 EPA Methods 1624, 1625, 1664, and OIA- 1677 (Volatile Organics, 

Semivolatile Organics, HEM, SGT-HEM, and Available Cyanide) 

EPA used Methods 1624, 1625, 1664, and OIA-1677 to measure volatile organics, 

semivolatile organics, n-hexane extractable material (HEM)/silica gel treated n-hexane extractable 

material (SGT- HEM) and available cyanide, respectively. Industry used Method 1664 to measure 

HEM and SGT-HEM. Methods 1624, 1625, 1664, and OIA-1677 are approved at 40 CFR 136. 

These methods use the minimum level (ML) of quantitation. The ML is defined as the 

lowest level at which the entire analytical system must give a recognizable signal and an acceptable 

calibration point for the analyte. When an ML is published in a method, the Agency has demonstrated 

that the ML can be achieved in at least one well-operated laboratory. When that laboratory or another 

laboratory uses that method, the laboratory is required to demonstrate, through calibration of the 

instrument or analytical system, that it can achieve pollutant measurements at the ML. 

For volatile organics, semivolatile organics, HEM/SGT-HEM, and available cyanide, 

EPA used the method-specified MLs as the baseline values. In determining the pollutants of concern 

and in calculating the HEM/SGT-HEM standards, EPA substituted the value of the ML and assumed 

that the measurement was not quantitated when a quantitated value or sample-specific quantitation limit 

was reported with a value less than the ML specified in the method. For example, if the ML was 10 

g/L and the laboratory reported a quantitated value of 5 g/L, EPA assumed that the concentration was 

nonquantitated with a sample-specific quantitation limit of 10 g/L. The objective of this comparison 

was to identify any results for the pollutants reported below the method-defined ML. Results reported 

below the ML were changed to the ML to ensure that all results used by EPA were reliable. In most 

cases, the quantitated values and sample-specific quantitation limits were equal to or greater than the 

baseline values. 

B.4.2 EPA Methods 1620 and 200.7 (Metals) 

EPA used Method 1620 to measure the concentrations of metals. While Method 1620 

is not listed at 40 CFR 136 as an approved method, it represents a consolidation of the analytical 

B-4
Appendix B - Analytical Methods and Baseline Values 

techniques in several 40 CFR 136-approved methods, such as Method 200.7 (inductively coupled 

plasma atomic emission (ICP) spectroscopy of trace elements) and Method 245.1 (mercury cold vapor 

atomic absorption (CVAA) spectroscopy). This method was developed specifically for the effluent 

guidelines program. Method 1620 includes more metal analytes than are listed in the approved 

methods and contains quality control requirements at least as stringent as the 40 CFR 136-approved 

methods. Some industry-supplied results for aluminum, barium, beryllium, cadmium, calcium, 

chromium, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, sodium, vanadium, and 

zinc were determined by Method 200.7. Other industry-supplied results for metals were determined by 

EPA Methods 204.1, 206.2, 231.2, 239.1, 245.1, 245.2, 265.2, 270.2, 272.1, 279.1, 7041, 7060A, 

7740, and 7841. 

Method 1620 employs the concept of an instrument detection limit (IDL). The IDL is 

defined as "the smallest signal above background noise that an instrument can detect reliably."3 Data 

reporting practices for Method 1620 analyses follow conventional metals reporting practices used in 

other EPA programs, in which values are required to be reported at or above the IDL. In applying 

Method 1620, IDLs are determined on a quarterly basis by each analytical laboratory and are, 

therefore, laboratory-specific and time-specific. Although Method 1620 contains MLs, these MLs 

pre-date EPA's recent refinements of the ML concept described earlier. The MLs associated with 

Method 1620 are based on a consensus opinion reached between EPA and laboratories during the 

1980s regarding levels that could be considered reliable quantitation limits when using Method 1620. 

These limits do not reflect advances in technology and instrumentation since the 1980s. Consequently, 

the IDLs, which are more reflective of current analytical capabilities, were used as the lowest values for 

reporting purposes, with the general understanding that reliable results can be produced at or above the 

IDL. Although the baseline values were derived from the MLs (or adjusted MLs) in Method 1620, 

EPA used the laboratory-reported quantitated values and sample-specific quantitation limits, which 

captured concentrations down to the IDLs, in its data analyses. 

In general, EPA used the MLs specified in Method 1620 as the baseline values. 

However, EPA adjusted the baseline value for lead to 50 :g/L and boron to 100 :g/L. In Method 

1620, lead has an ML of 5 :g/L for graphite furnace atomic absorption (GFAA) spectroscopy 

analysis; EPA determined, however, that it was not necessary for the laboratories to measure down to 

such low levels, and that lead could be analyzed by inductively coupled plasma atomic emission (ICP) 

spectroscopy. Consequently, the ML requirement was adjusted to 50 :g/L, the ML for the ICP 

method. In Method 1620, boron has an ML of 10 :g/L, but laboratory feedback years ago indicated 

that laboratories could not reliably achieve this low level. As a result, EPA only required laboratories to 

measure values at 100 :g/L and above. Thus, EPA adjusted the baseline value to 100 :g/L. 

3

Keith, L.H., W. Crummett, J. Deegan, R.A. Libby, J.K. Taylor, G. Wentler (1983). “Principles of Environmental 

Analysis,” Analytical Chemistry, Volume 55, Page 2217. 

B-5 
Appendix B - Analytical Methods and Baseline Values 

B.4.3 EPA Method 335.1 (Amenable Cyanide) 

Amenable cyanide was measured using Method 335.1, which is approved at 40 CFR 

136. Industry also supplied data determined by Method 335.1. Method 335.1 utilizes either a 

titrimetric or colorimetric procedure to measure amenable cyanide. 

Method 335.1 has a lower measurement range limit of 0.02 milligrams per liter (mg/L) 

for the colorimetric procedure and a lower measurement range limit of 1 mg/L for the titrimetric 

procedure. The nominal quantitation limit of 0.02 mg/L was used as the baseline for all amenable 

cyanide results, since it is the lower value of the two. 

B.4.4 EPA Methods 350.2 and 350.3 (Ammonia as Nitrogen) 

Ammonia, as nitrogen, was measured using Methods 350.2 and 350.3, both of which 

are approved at 40 CFR 136. Method 350.2 utilizes colorimetric, titrimetric, or electrode procedures 

to measure ammonia. Method 350.3 uses a potentiometric procedure to measure ammonia. 

Method 350.2 has a lower measurement range limit of 0.20 mg/L for the colorimetric 

and electrode procedures, and a lower measurement range limit of 1.0 mg/L for the titrimetric 

procedure. Method 350.3 has a lower measurement range limit of 0.03 mg/L for the potentiometric 

procedure. Rather than use different baseline values for the same pollutant, EPA used 0.03 mg/L as the 

baseline value from Method 350.3 because it represents the lowest value at which ammonia as nitrogen 

can be measured reliably. 

B.4.5 EPA Method 405.1 and SM 5210B (BOD5 and Carbonaceous BOD5) 

Biochemical oxygen demand (BOD5) and carbonaceous BOD5 (cBOD5) were 

measured using Method 405.1 and Standard Method (SM) 5210B, both of which are approved at 40 

CFR 136. BOD5 and cBOD5 are determined by the same method, except that an organic compound 

is added to the cBOD5 test to inhibit nitrogenous oxygen demand. If the sample does not include any 

nitrogenous demand to inhibit, the results should be comparable for BOD5 and cBOD5. 

Method 405.1 and SM 5210B are identical and the nominal quantitation limit, which is 

expressed in the methods as the lower limit of the measurement range at 2 mg/L, is the same for both 

forms of BOD5. EPA used this nominal quantitation limit of 2 mg/L as the baseline value in determining 

the pollutants of concern. 

B.4.6 EPA Methods 410.1, 410.2, and 410.4 (Chemical Oxygen Demand) 

Chemical Oxygen Demand (COD) was measured using Methods 410.1, 410.2, and 

410.4, all of which are approved at 40 CFR 136. Method 410.4 is a colorimetric procedure. 

Methods 410.1 and 410.2 are titrimetric procedures that follow identical analytical protocols; they 

B-6
Appendix B - Analytical Methods and Baseline Values 

differ only in the range of COD concentration that they are designed to measure. Reagent 

concentrations and sample volumes are adjusted to accommodate a wide range of sample 

concentrations, since the dynamic range of the chemistry used to detect COD is somewhat limited. 

Data from all three of these methods are directly comparable. 

Method 410.1 is designed to measure mid-level concentrations (greater than 50 mg/L) 

of COD and is associated with a nominal quantitation limit of 50 mg/L. Method 410.2 is designed to 

measure low-level concentrations in the range of 5-50 mg/L. Method 410.4 has a measurement range 

of 3-900 mg/L for automated procedures and measurement range of 20-900 mg/L for manual 

procedures. EPA contracts required that laboratories measure down to the lowest quantitation limit 

possible for whatever method is used. Therefore, if the laboratory analyzes a sample using Method 

410.1 and obtains a nonquantitated result, it must reanalyze the sample using Method 410.2. Thus, the 

quantitation limit reported for nonquantitated was 5 mg/L, unless sample dilutions were required for 

complex matrices. 

For all COD data, EPA used the baseline value of 5 mg/L that is associated with the 

lower quantitation limit for the titrimetric procedures because most of the data used to determine COD 

were obtained by the titrimetric procedures (i.e., Methods 410.1 and 410.2). 

B.4.7 EPA Method 325.3 (Chloride) 

Chloride was measured using Method 325.3, which is approved at 40 CFR 136. 

Method 325.3 is a titrimetric procedure and measures concentrations greater than 1 mg/L; therefore, 

EPA used the baseline value of 1 mg/L. 

B.4.8 EPA Method 340.2 (Fluoride) 

Fluoride was determined by Method 340.2, which is approved at 40 CFR 136. 

Method 340.2 is a potentiometric procedure that uses a fluoride electrode. The nominal quantitation 

limit of 0.1 mg/L is expressed in the method as the lower limit of the measurement range. This nominal 

quantitation limit was used as the baseline value for fluoride. 

B.4.9 EPA Method 218.4, SM 3111A, and SM 3500D (Hexavalent Chromium) 

For EPA sampling episodes, hexavalent chromium was determined by Method 218.4 

and SM 3500D, which are approved at 40 CFR 136. Industry supplied data generated by SM 3111A 

which is not approved at 40 CFR 136. Method 218.4 utilizes atomic absorption for the determination 

of hexavalent chromium after chelation and extraction. SM 3500D is a colorimetric procedure using 

reaction with diphenylcarbazide to produce a color proportional to Cr6+ concentration. SM 3111A 

utilizes flame atomic absorption spectrometry to measure Cr6+ or total Cr. 

B-7
Appendix B - Analytical Methods and Baseline Values 

In Method 218.4, SM 3111A, and SM 3500D, the nominal quantitation limit or lower 

limit of the measurement range is 0.01 mg/L. Because EPA used Methods 218.4 and SM 3500D for 

analysis, the nominal quantitation limit of 0.01 mg/L was used as the baseline value for all hexavalent 

chromium results. 

B.4.10 EPA Method 150.1 and SM 4500H (pH) 

For EPA sampling episodes, pH was determined by Method 150.1. For industrysupplied data, pH was determined by SM 4500H. Both methods are approved at 40 CFR 136. For 

Method 150.1 and SM 4500H, the pH of a sample is determined electrometrically using either a glass 

electrode in combination with a reference potential or a combination electrode. There are no nominal 

quantitation limits for either Method 150.1 or SM 4500H. 

B.4.11 EPA Methods 375.2 and 375.4 (Sulfate) 

For EPA sampling episodes, sulfate was measured by Methods 375.2 and 375.4. For 

industry-supplied data, sulfate was measured by Method 375.4. Both of these methods are approved 

at 40 CFR 136. Method 375.2 is a colorimetric procedure that uses the decrease in color caused by 

the formation of barium sulfate to measure the sulfate concentration. Method 375.4 measures the 

turbidity created by the insoluble barium sulfate in solution. A dispersant/buffer is added to the solution 

to aid in creating uniform suspension of the barium sulfate. 

The nominal quantitation limit (also the lower limit of the measurement range) for 

Method 375.2 is 0.50 mg/L. The nominal quantitation limit (also the lower limit of the measurement 

range) for Method 375.4 is 1 mg/L. EPA used the baseline value of 1 mg/L that is associated with the 

higher quantitation limit for all the sulfate data, rather than having multiple baseline values, because most 

of the sulfate data was determined by Method 375.4. 

B.4.12 EPA Methods 335.2 and 335.3 (Total Cyanide) 

EPA determined total cyanide using Method 335.2. Industry determined total cyanide 

by Methods 335.2 and 335.3. Both methods are approved at 40 CFR 136. Method 335.2 uses 

either titration with silver nitrate, or colorimetry with an organic dye, to measure total cyanide. Method 

335.3 uses an automated distillation-colorimetry procedure for continuous flow analytical systems that 

utilizes UV oxidation to measure total cyanide. 

The nominal quantitation limit for Method 335.2, expressed in the method as the lower 

limit of the measurement range, is 0.02 mg/L. The nominal quantitation limit for Method 335.3, also 

expressed as the lower limit of the measurement range, is 0.005 mg/L. Because EPA used Method 

335.2, the Agency used the nominal quantitation limit of 0.02 mg/L as the baseline value for all total 

cyanide results. 

B-8
Appendix B - Analytical Methods and Baseline Values 

B.4.13 EPA Method 160.1 and SM 2540C (Total Dissolved Solids) 

EPA determined total dissolved solids (TDS) by Method 160.1. Industry determined 

TDS by SM 2540C. Both methods are approved at 40 CFR 136 under "residue-filterable." Method 

160.1 and SM 2540C are gravimetric methods with a lower limit of the measurement range of 10 

mg/L; this value is the nominal quantitation limit. The nominal quantitation limit of 10 mg/L is also the 

baseline value. 

B.4.14 EPA Method 351.3 (Total Kjeldahl Nitrogen) 

EPA determined total Kjeldahl nitrogen (TKN) by Method 351.3, which is approved 

at 40 CFR 136. Method 351.3 is a manual colorimetric analysis that has a lower measurement range 

limit, which is also the nominal quantitation limit, of 1.0 mg/L. The nominal quantitation limit of 1.0 mg/L 

is also the baseline value. 

B.4.15 EPA Method 415.1 (Total Organic Carbon) 

EPA determined total organic carbon (TOC) by Method 415.1, which is approved at 

40 CFR 136. Method 415.1 is a combustion (or oxidation) method with a lower measurement range 

limit of 1 mg/L. EPA used this nominal quantitation limit of 1 mg/L as the baseline value. 

B.4.16 EPA Methods 420.1 and 420.2 (Total Phenols) 

In EPA's database, the terms "total phenols" and "total recoverable phenolics" are used 

synonymously. The term "total recoverable phenolics" is used in the titles of Methods 420.1 to 420.4. 

While "total recoverable phenolics" could be considered a more accurate term for what is measured in 

any of these related methods, both terms refer to an aggregate measure of compounds with a 

phenol-like or "phenolic" structure. The use of the adjective "recoverable" simply recognizes that there 

are some compounds that are not measured, as well as other related compounds in this class. Thus, the 

method reports what can be recovered from the sample under the conditions of the analysis. 

The methods for the analysis of total phenols employ the reagent 4-aminoantipyrine 

(4AAP), which reacts with phenolic compounds to produce a dark red product, an antipyrine dye. 

The concentration of the phenolic compounds is determined by measuring the absorbance of the sample 

at a wavelength of 460 to 520 nm, depending on the method. The methods are calibrated using a series 

of standards containing the single compound phenol. Methods 420.1 and 420.2, the two methods 

approved at 40 CFR 136, provide several options for sample preparation and analysis, including a 

preliminary distillation designed to remove interferences, and a chloroform extraction procedure in 

Method 420.1 that is designed to improve the sensitivity of the method. Both methods also provide 

information on the concentrations of the calibration standards that may be prepared for a given set of 

procedural options. 

B-9
Appendix B - Analytical Methods and Baseline Values 

The methods themselves do not contain a required calibration range. Each laboratory 

can, and does, establish a calibration range based on its use of the method. EPA used a baseline value 

of 0.05 mg/L because this was the most commonly reported sample-specific detection limit in EPA's 

sampling episode data (these data included more concentrated samples than effluent). 

B.4.17 EPA Methods 365.2 and 365.3 (Total Phosphorus) 

EPA determined total phosphorus by Methods 365.2 and 365.3. Both methods are 

approved at 40 CFR 136. Total phosphorus represents all of the phosphorus present in the sample, 

regardless of form, as measured by the persulfate digestion procedure. 

The two methods differ only in the preparation of one of the reagents. Method 365.2 

specifies the separation of the ammonium molybdate and the antimony potassium tartrate from the 

ascorbic acid reagent. Method 365.3 allows for combining these reagents into a single solution. 

Because the chemistry is unaffected, the data are directly comparable. 

These methods have the same nominal quantitation limit of 0.01 mg/L. EPA used this 

value as the baseline value for total phosphorus. 

B.4.18 EPA Methods 376.1 and 376.2, SM 4500D and SM 4500E, and D4658 (Total 

Sulfide) 

EPA determined total sulfide by Methods 376.1, 376.2, and SM 4500E, all of which 

are approved at 40 CFR 136. Industry determined sulfide by SM 4500D and ASTM Method D4658. 

SM 4500D is approved at 40 CFR 136, while ASTM Method D4658 is not approved at 40 CFR 

136. Method 376.1 and SM 4500E utilize an iodine solution to oxidize any sulfide present in the 

sample. The remaining iodine is then titrated with sodium thiosulfate in the presence of a starch solution. 

The quantity of iodine added to the sample and the titrant required to neutralize the remaining iodine 

give the sulfide concentration by calculation. Method 376.2 and SM 4500D use the reaction of the 

sulfide ion with ferric chloride and dimethyl-P-phenylenediamine to produce deeply colored methylene 

blue. The color is proportional to the sulfide concentration. ASTM Method D4658 utilizes an 

ion-selective electrode to determine sulfide ion in water. 

EPA collected sulfide data for 236 samples in seven post-proposal sampling episodes 

using Methods 376.1, 376.2, and SM 4500E (EPA Episode numbers 6455, 6456, 6457, 6458, 6461, 

6462, and 6463). These samples were collected from both process wastewaters prior to treatment and 

effluent wastewater after treatment. EPA reviewed the analytical data from these 236 samples and 

compared the three different methods. The study is included in the rulemaking record (see Section 

16.2 of the rulemaking record, DCN 16941) and a summary of the findings are in the notice of data 

availability (67 FR 38754; June 5, 2002). 

B-10
Appendix B - Analytical Methods and Baseline Values 

The nominal quantitation limit for Method 376.1 and SM 4500E, which is also the 

lower limit of the measurement range, is 1.0 mg/L. The nominal quantitation limit for Method 376.2 

and SM 4500D is 0.5 mg/L. The nominal quantitation limit for D4658, which is also the lower limit of 

the measurement range, is 0.04 mg/L. Rather than use different baseline values for the same pollutant, 

EPA used the 1.0 mg/L as the baseline value from Method 376.1 because the majority of the data were 

determined by this method. 

B.4.19 EPA Method 160.2 and SM 2540D (Total Suspended Solids) 

EPA determined total suspended solids (TSS) by Method 160.2. Industry determined 

TSS by SM 2540D. Both methods are approved at 40 CFR 136 under "residue-non-filterable." 

Method 160.2 and SM 2540D are gravimetric methods with a lower limit of the measurement range of 

4 mg/L; this value is also the nominal quantitation limit. The nominal quantitation limit of 4 mg/L is the 

baseline value. 

B.4.20 EPA Method 204.1 and 7041 (Antimony) 

Industry determined antimony by Methods 204.1 and 7041. Method 204.1 is 

approved at 40 CFR 136. Method 7041 is from Test Methods for Evaluating Solid Waste, 

Physical/Chemical Methods (SW-846). Although Method 7041 is not listed at 40 CFR 136, it is 

approved for analyses of samples under the RCRA regulations at 40 CFR 261. Method 204.1 utilizes 

direct-aspiration atomic absorption as the determinative technique to measure antimony. Method 

7041 utilizes the furnace technique in conjunction with an atomic absorption spectrophotometer. 

The nominal quantitation limit (also the lower limit of the measurement range) for 

Method 204.1 is 1.0 mg/L. The nominal quantitation limit (also the lower limit of the measurement 

range) for Method 7041 is 20 :g/L. Rather than use different baseline values for the same pollutant, 

EPA used the minimum level of 20 :g/L for antimony from Method 1620 as the baseline value, 

because this was the method that EPA used for the determination of antimony. 

B.4.21 EPA Method 206.2 and 7060A (Arsenic) 

Industry determined arsenic by Methods 206.2 and 7060A. Method 206.2 is 

approved at 40 CFR 136. Method 7060A is from Test Methods for Evaluating Solid Waste, 

Physical/Chemical Methods (SW-846). Although Method 7060A is not listed at 40 CFR 136, it is 

approved for analyses of samples under the RCRA regulations at 40 CFR 261. Methods 206.2 and 

7060A utilize the furnace technique in conjunction with an atomic absorption spectrophotometer. 

The nominal quantitation limit (also the lower limit of the measurement range) for 

Method 206.2 and Method 7060A is 5.0 :g/L. Rather than use different baseline values for the same 

pollutant, EPA used the minimum level of 10 :g/L for arsenic from Method 1620 as the baseline value, 

because this was the method that EPA used for the determination of arsenic. 

B-11
Appendix B - Analytical Methods and Baseline Values 

B.4.22 EPA Method 231.2 (Gold) 

EPA determined gold by Method 231.2, since this parameter is only semiquantitatively 

analyzed by Method 1620. Method 231.2 is approved at 40 CFR 136. Method 231.2 utilizes the 

furnace technique in conjunction with an atomic absorption spectrophotometer. The nominal 

quantitation limit for gold, which is also the lower limit of the measurement range, is 5 :g/L. The 

nominal quantitation limit is also the baseline value. 

B.4.23 EPA Method 239.1 (Lead) 

Industry determined lead by Method 239.1, which is approved at 40 CFR 136. 

Method 239.1 utilizes direct-aspiration atomic absorption as the determinative technique to measure 

lead. The nominal quantitation limit of 0.1 mg/L is expressed in the method as the lower limit of the 

measurement range. Rather than use different baseline values for the same pollutant, EPA used the 

minimum level of 50 :g/L for lead from Method 1620 from the ICP technique, as the baseline value 

since this was the method that EPA used for the determination of lead. 

B.4.24 EPA Methods 245.1 and 245.2 (Mercury) 

Industry determined mercury by Methods 245.1 and 245.2, both of which are 

approved at 40 CFR 136. The methods utilize cold vapor atomic absorption as the determinative 

technique to measure mercury. The nominal quantitation limit for both methods is 0.2 :g/L, which is 

also expressed as the lower limit of the measurement range. The nominal quantitation limit matches the 

nominal quantitation limit from Method 1620, which EPA used to determine mercury. The nominal 

quantitation limit is the same as the baseline value of 0.2 :g/L. 

B.4.25 EPA Method 265.2 (Rhodium) 

EPA determined rhodium by Method 265.2, since this parameter is only 

semiquantitatively analyzed by Method 1620. Method 265.2 is approved at 40 CFR 136. Method 

265.2 utilizes the furnace technique in conjunction with an atomic absorption spectrophotometer. The 

nominal quantitation limit for rhodium, which is also the lower limit of the measurement range, is 20 

:g/L. The nominal quantitation limit is also the baseline value. 

B.4.26 EPA Methods 270.2 and 7740 (Selenium) 

Industry determined selenium by Methods 270.2 and 7740. Method 270.2 is 

approved at 40 CFR 136. Method 7740 is from Test Methods for Evaluating Solid Waste, 

Physical/ Chemical Methods (SW-846). Although Method 7740 is not listed at 40 CFR 136, it is 

approved for analyses of samples under the RCRA regulations at 40 CFR 261. Methods 270.2 and 

7740 utilize the furnace technique in conjunction with an atomic absorption spectrophotometer. 

B-12
Appendix B - Analytical Methods and Baseline Values 

The nominal quantitation limit for Method 270.2 and Method 7740, which is also lower 

limit of the measurement range, is 5.0 :g/L. Rather than use different baseline values for the same 

pollutant, EPA used the minimum level of 5 :g/L for selenium from Method 1620 as the baseline value, 

since this was the method that EPA used for the determination of selenium. 

B.4.27 EPA Method 272.1 (Silver) 

Industry determined silver by Method 272.1, which is approved at 40 CFR 136. 

Method 272.1 utilizes direct-aspiration atomic absorption as the determinative technique to measure 

silver. The nominal quantitation limit of 0.1 mg/L is expressed in the method as the lower limit of the 

measurement range. Rather than use different baseline values for the same pollutant, EPA used the 

minimum level of 10 :g/L for silver from Method 1620 as the baseline value, since this was the method 

that EPA used for the determination of silver. 

B.4.28 EPA Methods 279.1 and 7841 (Thallium) 

Industry determined thallium by Methods 279.1 and 7841. Method 279.1 is approved 

at 40 CFR 136. Method 7841 is from Test Methods for Evaluating Solid Waste, Physical/ 

Chemical Methods (SW-846). Although Method 7841 is not listed at 40 CFR 136, it is approved for 

analyses of samples under the RCRA regulations at 40 CFR 261. Method 279.1 utilizes 

direct-aspiration atomic absorption as the determinative technique to measure thallium. Method 7841 

utilizes the furnace technique in conjunction with an atomic absorption spectrophotometer. 

The nominal quantitation limit for Method 279.1, which is also the lower limit of the 

measurement range, is 1.0 mg/L. The nominal quantitation limit for Method 7841, which is also the 

lower limit of the measurement range, is 5 :g/L. Rather than use different baseline values for the same 

pollutant, EPA used the minimum level of 10 :g/L for thallium from Method 1620 as the baseline 

value, since this was the method that EPA used for the determination of thallium. 

B.4.29 EPA Methods 624 and 625 (Volatile Organics and Semivolatile Organics) 

EPA included industry-supplied data from Methods 624 and 625, both of which are 

approved at 40 CFR 136. Methods 624 and 625 are GC/MS methods, similar to Methods 1624 and 

1625, except that Methods 624 and 625 do not utilize isotope dilution. The nominal quantitation limits 

are expressed as the lower limit of the measurement range, typically the concentration of the lowest 

calibration standard. However, rather than use different baseline values for the same pollutants 

(Methods 624 and 625 have many of the same analytes as Methods 1624 and 1625), EPA used the 

minimum levels that are listed in Methods 1624 and 1625 as the baseline values, since these methods 

were used by EPA for the determination of volatile and semivolatile organic analytes. 

B-13
Appendix B - Analytical Methods and Baseline Values 

B.4.30 EPA Method 630.1 (Ziram) 

Ziram was determined by Method 630.1. There are no methods approved at 40 CFR 

136 for ziram. In this method, the sample is digested with acid to yield CS2 by hydrolysis of the 

dithiocarbamate moiety. The evolved CS2 is extracted from the water with hexane and the extract is 

injected into a GC. The nominal quantitation limit was determined by a low-point calibration standard. 

The nominal quantitation limit for ziram is 10 :g/L and was used as the baseline value. 

Analytical Method Development Efforts 

Section 304(h) of the Clean Water Act directs EPA to promulgate guidelines 

establishing test procedures for the analysis of pollutants. These methods allow the analyst to determine 

the presence and concentration of pollutants in wastewater. The methods are used for compliance 

monitoring, for filing applications for the NPDES program under 40 CFR 122.21, 122.41, 122.44 and 

123.25, and for the implementation of the pretreatment standards under 40 CFR 403.10 and 403.12. 

To date, EPA has promulgated methods for all conventional and toxic pollutants, and for some 

nonconventional pollutants. 

Currently approved methods for metals and wet chemistry parameters are included in 

the table of approved inorganic test procedures at 40 CFR 136.3, Table I-B. Table I-C at 40 CFR 

136.3 lists approved methods for measurement of nonpesticide organic pollutants, and Table I-D lists 

approved methods for the toxic pesticide pollutants and for other pesticide pollutants. Dischargers must 

use the test methods promulgated at 40 CFR 136.3 or incorporated by reference in the tables, when 

available, to monitor pollutant discharges from the metal products and machinery (MP&M) industry, 

unless specified otherwise in 40 CFR 413, 433, 438, 463, 464, 467, and 471, or by the permitting 

authority. 

Table I-C does not include six of the MP&M semivolatile organic pollutants and one of 

the MP&M volatile organic pollutant that EPA is regulating in the rule. Although these pollutants are 

missing from Table I-C, the analyte list for Method 1624 contains the volatile organic pollutant and the 

analyte list for Method 1625 contains the six semivolatile organic pollutants. EPA promulgated both of 

these methods for use in Clean Water Act measurement programs at 40 CFR 136, Appendix A. 

As a part of the rule, EPA will allow the use of modified versions of Methods 624 and 

1624 for the determination of the additional volatile organic pollutant and modified versions of Methods 

625 and 1625 for the determination of the additional six semivolatile organic pollutants. 

The modifications to Methods 624, 625, 1624, and 1625 have been included in the 

Docket for the rule. The modifications to Methods 624, 625, 1624, and 1625 consist of text, 

performance data, and quality control (QC) acceptance criteria for the additional analytes. This 

information will allow a laboratory to practice the methods with the additional analytes as an integral 

part. EPA conducted an interlaboratory validation study on the modifications to these methods. The 

B-14

B.5 
Appendix B - Analytical Methods and Baseline Values 

data from the interlaboratory study and the proposed modifications to the method were made available 

for public comment in a notice of data availability (see Section B.4.18). EPA is promulgating these 

method modifications for monitoring MP&M industry wastewaters at 40 CFR 136 in the rule. 

As part of the rule, the following pollutants will be added to their respective analyte lists 

for the MP&M industry only: 

Methods Pollutant CAS Number 

EPA Methods 624/1624 carbon disulfide 75-15-0 

EPA Methods 625/1625 aniline 62-53-3 

EPA Methods 625/1625 3,6-dimethylphenanthrene 1576-67-6 

EPA Methods 625/1625 2-isopropylnaphthalene 2027-17-0 

EPA Methods 625/1625 1-methylfluorene 1730-37-6 

EPA Methods 625/1625 2-methylnaphthalene 91-57-6 

EPA Methods 625/1625 1-methylphenanthrene 832-69-9 

B-15
Appendix B - Analytical Methods and Baseline Values 

Table B-1

Analytical Methods and Baseline Values

Analyte Method 

CAS 

Number 

Samples 

Collected and 

Analyzed by 

Nominal 

Quantitation 

Value (mg/L) 

Baseline 

Value 

(mg/L) 

Amenable Cyanide 335.1 C025 EPA, Industry 0.02 0.02 

Ammonia as Nitrogen 350.2 766417 EPA 0.05 0.05 

350.3 0.03 

Available Cyanide OIA-1677 C054 EPA 0.002 0.002 

BOD 

Carbonaceous BOD 

405.1 C003 EPA 2.00 2.00 

5210B C002 2.00 

Chemical Oxygen Demand 410.1 C004 EPA 50.00 5.00a 

410.2 5.00 

410.4(automated)b 3.00 

410.4(manual)b 20.00 

Chloride 325.3 16887006 EPA 1.00 1.00 

Fluoride 340.2 16984488 EPA 0.10 0.10 

HEM, SGT-HEM 1664 C036, C037 EPA, Industry 5.00 5.00 

Hexavalent Chromium 218.4 18540299 EPA 0.01 0.01 

3111A Industry 0.01 

3500D EPA 0.01 

Metals 1620 c EPA c c 

200.7 c Industry c c 

pH 150.1 C006 EPA N/A 

4500H Industry N/A 

Semivolatile Organics 1625 c EPA c c 

625 Industry 

Sulfate 375.2 14808798 EPA 3.00 1.00 

375.4 EPA, Industry 1.00 

Total Cyanide 335.2 57125 EPA, Industry 0.02 0.02 

335.3 Industry 0.005 

TDS 160.1 C010 EPA 10.00 10.00 

2540C Industry 10.00 

TKN 351.3 C021 EPA 1.00 1.00 

TOC 415.1 C012 EPA 1.00 1.00 

Total Phenols 420.1 C020 EPA d 0.05 

420.2 d 

Total Phosphorus 365.2 14265442 EPA 0.01 0.01 

365.3 0.01 

B-16
Appendix B - Analytical Methods and Baseline Values 

Table B-1 (Continued) 

Analyte Method 

CAS 

Number 

Samples 

Collected and 

Analyzed by 

Nominal 

Quantitation 

Value (mg/L) 

Baseline 

Value 

(mg/L) 

Total Sulfide 376.1 18496258 EPA 1.00 1.00 

376.2 0.10 

4500D Industry 0.50 

4500E EPA 1.00 

D4568 Industry 0.04 

TSS 160.2 C009 EPA 4.00 4.00 

2540D Industry 4.00 

Volatile Organics 1624 c EPA c c 

624 Industry 

Ziram 630.1 137304 EPA 0.01 0.01 

a

The baseline value was adjusted to reflect the lowest nominal quantitation limit of the titrimetric procedures (i.e.,

410.1, 410.2, and 5220B). See Section B.4.6 for a detailed explanation. b

Method 410.4 lists two different quantitation limits that are dependent upon whether the automated or manual

protocols were followed. The automated method limit =3 mg/L and the manual method limit =20 mg/L. c

The method analyzed a number of pollutants each with its own CAS number, baseline value, and nominal

quantitation limit.

d

The method does not have a required calibration range. The baseline value is based upon the most frequently

reported sample-specific detection limit.

B-17
Appendix C - Wastewater Characteristics 

Appendix C

WASTEWATER CHARACTERISTICS
Appendix C - Wastewater Characteristics 

Appendix C 

WASTEWATER CHARACTERISTICS 

This appendix summarizes the characteristics of wastewater generated by unit 

operations evaluated for the final rule and discharged to wastewater treatment systems. The 

wastewaters characterized in this appendix can be grouped into the following types of wastewaters: 

C Hexavalent chromium-bearing wastewater;

C Cyanide-bearing wastewater;

C Oil-bearing and organic pollutant-bearing wastewaters;

C Chelated metal-bearing wastewater; and

C Metal-bearing wastewater.

EPA evaluated a number of unit operations for the May 1995 proposal, January 2001 

proposal, and June 2002 NODA (see Tables 4-3 and 4-4). However, EPA selected a subset of these 

unit operations for regulation in the final rule (see Section 1.0). For this appendix, the term "proposed 

MP&M operations" means those operations evaluated for the two proposals, NODA, and final rule. 

The term "final MP&M operations" means those operations defined as "oily operations" (see Section 

1.0, 40 CFR 438.2(f), and Appendix B to Part 438) and regulated by the final rule. 

Sections C.1 through C.5 summarize, for each type of wastewater, analytical data 

obtained during the MP&M regulatory development process for unit operations and influents to the 

wastewater treatment systems. These subsections present the number of samples analyzed, the number 

of times each pollutant was detected, and the minimum, maximum, mean, and median pollutant 

concentrations. Oil-bearing and organic pollutant-bearing wastewaters are characterized in Section 

5.0. 

Analytical data from the MP&M sampling program, including data obtained from 

sanitation districts, facilities performing proposed MP&M operations, and MP&M industry trade 

associations, are in the sampling episode reports located in Sections 5.2 and 15.3 of the rulemaking 

record. 

C.1 Hexavalent Chromium-Bearing Wastewater 

Hexavalent chromium-bearing wastewater exhibits high concentrations of hexavalent 

chromium and may contain other metals, and generally has a low pH of approximately 2. Sections 

C.1.1 and C.1.2 present chromium data for process water and associated rinse water and for the 

influent to the chromium reduction process, respectively. 

C-1
Appendix C - Wastewater Characteristics 

C.1.1 Process Water and Rinse Water 

Hexavalent chromium is present in process bath wastewater from various unit 

operations (e.g., chromic acid anodizing, chromate conversion coating, and chromium electroplating). 

Table C-1 presents the number of samples collected and analyzed during EPA’s sampling program for 

unit operations and associated rinses that generate hexavalent chromium-bearing wastewater. 

Table C-1 

Number of Process and Rinse Water Samples for Unit Operations That 

Generate Hexavalent Chromium-Bearing Wastewater 

Unit Operation 

No. of Process Water 

Samples 

No. of Rinse Water 

Samples 

Acid Treatment with Chromium 

Anodizing with Chromium 

Chromate Conversion Coating (Or Chromating) 

Electroplating with Chromium 

Wet Air Pollution Control 

1 

2 

16 

4 

6 

3 

7 

23 

10 

NA 

Source: MP&M Sampling Program.

NA - Not applicable. No associated rinse.

The mean total and hexavalent chromium concentrations in process bath water from 

these operations are 24,120 milligrams per liter (mg/L) and 10.0 mg/L, respectively. In the associated 

rinses, the mean concentrations for total and hexavalent chromium are 156 mg/L and 10.3 mg/L, 

respectively. Table C-2 summarizes total and hexavalent chromium concentration data for the process 

bath water and rinse water samples with detected concentrations for the unit operations listed in Table 

C-1. 

Table C-2 

Chromium Concentration Data for Process Water and Rinse Water 

Source 

Chromium 

Form 

No. of 

Samples 

Analyzed 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Process 

Water 

Total 29 29 0.045 139,000 24,120 2,990 

Hexavalent 2 1 10.0 10.0 10.0 10.0 

Rinse Water 

Total 43 43 0.22 1,762 156 12.8 

Hexavalent 6 6 2.1 21.2 10.3 8.0 

Source: MP&M Sampling Program. 

C-2 
Appendix C - Wastewater Characteristics 

C.1.2 Influent to Chromium Reduction Process 

Facilities performing proposed MP&M operations usually segregate hexavalent 

chromium-bearing wastewater and treat it in a chromium reduction unit before commingling it with other 

process wastewater for further treatment. This segregated wastewater requires preliminary treatment to 

reduce hexavalent chromium to trivalent chromium because the chemical precipitation systems typically 

used to treat the commingled wastewater do not effectively treat hexavalent chromium. Typical chrome 

treatment involves chromium reduction using sulfur dioxide, sodium bisulfite, sodium metabisulfite, 

peroxide, or ferrous sulfate (see Section 8.4.1). Table C-3 presents the total and hexavalent chromium 

concentration data for samples of the influent to the chromium reduction process collected during 

EPA’s sampling program. The treatment influent typically represents several commingled 

wastestreams, most of which are rinses. The influent-to-treatment concentrations are typically lower 

than the concentrations of process and rinse water due to the number of high-flow, low-concentration 

rinses that are commingled prior to treatment. 

Table C-3 

Chromium Concentration Data for the Influent to the 

Chromium Reduction Process 

Form of Chromium 

No. of Samples 

Analyzed 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Total Chromium 54 54 0.2 432 54.8 18.2 

Hexavalent Chromium 21 18 0.027 20 6.7 4.0 

Source: MP&M Sampling Program. 

Cyanide-Bearing Wastewater 

Cyanide-bearing wastewater exhibits high concentrations of cyanide and metals such as 

copper, cadmium, and zinc, and generally has a high pH of approximately 12. Electroplating baths 

usually are the source of the high concentrations of cyanide. Cyanide may be analyzed as total cyanide 

(i.e., all forms included), amenable cyanide (i.e., cyanide present in forms amenable to treatment using 

alkaline chlorination), or weak-acid-dissociable cyanide (i.e., cyanide that dissociates in a weak acid). 

Sections C.2.1 and C.2.2 present cyanide concentration data for cyanide-bearing wastewater 

generated in proposed MP&M operations and in the influent to the cyanide treatment processes, 

respectively. 

C-3

C.2 
Appendix C - Wastewater Characteristics 

C.2.1 Process Water and Rinse Water 

Table C-4 presents the number of process and rinse water samples collected and 

analyzed during EPA’s sampling program for proposed MP&M operations that generate cyanidebearing wastewater. 

Table C-4 

Number of Process and Rinse Water Samples for Unit Operations 

That Generate Cyanide-Bearing Wastewater 

Unit Operation No. of Process Water Samples No. of Rinse Water Samples 

Alkaline Treatment with Cyanide 

Electroplating with Cyanide 

Wet Air Pollution Control 

2 

11a 

3 

4 

13 

NA 

Source: MP&M Surveys and MP&M Site Visits.

a

Does not include one sample from a gold-cyanide electroplating bath that was analyzed only for metals.

NA - Not applicable. No associated rinse.

Cyanide is used as a complexing agent in electroplating and cleaning baths and is 

present in wastewater generated in the wet air pollution control systems. Table C-5 summarizes the 

total and amendable cyanide concentration data for the process water and rinse water samples with 

detected concentrations for the unit operations listed in Table C-4. 

Table C-5 

Cyanide Concentration Data for Process Water and Rinse Water 

Source 

Cyanide 

Form 

No. of 

Samples 

Analyzed 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Process 

Water 

Total 15 15 2.6 100,000 16,521 5,200 

Amenable 1 0 NA NA NA NA 

Rinse Water 

Total 17 17 0.054 135 38 12.7 

Amenable 3 3 61.5 135 100 104 

Source: MP&M Sampling Program.

NA - Not applicable. No samples were analyzed for amenable cyanide.

C-4
Appendix C - Wastewater Characteristics 

C.2.1 Influent to Cyanide Treatment Process 

Facilities performing proposed MP&M operations usually segregate cyanide-bearing 

wastewater generated and treat it in a cyanide reduction process before commingling it with other 

process wastewater for further treatment. This preliminary treatment prevents cyanide complexes from 

forming in the commingled wastewater. Typical cyanide treatment methods include alkaline chlorination 

with sodium hypochlorite or chlorine gas or ozone oxidation (see Section 8.4.3). These complexes 

decrease the effectiveness of chemical precipitation, the technology typically used to treat the 

commingled wastewater. Table C-6 summarizes the cyanide concentration data for the influent to 

cyanide treatment process. The treatment influent typically represents several commingled 

wastestreams, most of which are rinses. The influent-to-treatment concentrations are typically lower 

than the concentrations of process and rinse water due to the number of high-flow, low-concentration 

rinses that are commingled prior to treatment. 

Table C-6 

Cyanide Concentration Data for Influent 

to the Cyanide Treatment Process 

Form of 

Cyanide 

No. of Samples 

Analyzed No. of Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Total Cyanide 101 98 0.024 1,110 50.7 6.1 

Amenable Cyanide 70 65 0.01 394 34.4 3.15 

Source: MP&M Sampling Program. 

C.3 Oil-Bearing and Organic Pollutant-Bearing Wastewaters 

Oil-bearing wastewater exhibits high concentrations of oil and concentrations of organic 

pollutants. Oil-bearing wastewater is classified as containing either free (floating) oils or oil/water 

emulsions. As previously discussed above, “oily operations” are defined and regulated in the final rule 

and described in Section 4.0. The wastewater from oily operations is characterized in Section 5.0. In 

addition, EPA collected data on two proposed MP&M operations (Bilge Water and Dry Dock) that 

also generate oil-bearing and organic pollutant-bearing wastewaters. EPA is not regulating these two 

operations as EPA excluded the proposed Shipbuilding Dry Dock Subcategory from the final rule (see 

Section 9.0). Sampling episode reports for the proposed Shipbuilding Dry Dock Subcategory are 

located in Sections 5.2 and 15.2 of the rulemaking record. 

C.4 Chelated Metal-Bearing Wastewater 

Chelated metal-bearing wastewater exhibits high concentrations of metals, usually 

copper or nickel. Section C.4.1 discusses the various unit processes that generate chelated metalC-5
Appendix C - Wastewater Characteristics 

bearing wastewater and presents process water and rinse water pollutant concentration data for those 

processes collected during EPA’s sampling program. Section C.4.2 discusses the pollutant 

concentration data for the influent to chelation-breaking preliminary treatment systems. 

C.4.1 Process Water and Rinse Water 

Facilities performing proposed MP&M operations use chelating agents in unit 

operations to prevent metals from being precipitated in the process bath. Electroless plating processes 

and associated rinses are the most common proposed MP&M operations that generate chelated metalbearing wastewater. Some cleaning operations also generate chelated metal-bearing wastewater. 

To characterize process waters and associated rinse waters for proposed MP&M 

operations that use chelating agents, EPA collected 37 samples of electroless plating solutions and 

rinses from electroless nickel plating, or from electroless copper. The maximum concentration of nickel 

in the process water and the rinses was 7,530 mg/L and 378 mg/L, respectively. The maximum 

concentration of copper in the process water and the rinses was 14,200 mg/L and 138 mg/L, 

respectively. Only one sample of tin was taken from process water, which had a concentration of 

3.8 mg/L. Other metals typically plated using electroless plating include gold, palladium, and cobalt. 

C.4.2 Influent to Chelate-Breaking Preliminary Treatment System 

Typical chemical precipitation and sedimentation treatment processes do not remove 

chelated metals; therefore, facilities performing proposed MP&M operations usually segregate and 

pretreat chelated metal-bearing wastewater to break down the metal chelates before commingling it 

with other metal-bearing wastewaters. Preliminary treatment may consist of chemical reduction using 

reducing agents such as sodium borohydride, hydrazine, dithiocarbamate (measured analytically as 

ziram) or sodium hydrosulfite; high pH precipitation using calcium hydroxide or ferrous sulfate; or 

filtering the chelated metals out of solution (see Section 8.4.4). 

EPA measured copper in concentrations ranging from 570 to 700 mg/L in the influent 

to the preliminary treatment systems for electroless copper processes. EPA measured nickel in 

concentrations ranging from 0.149 to 480 mg/L in the influent to the preliminary treatment systems for 

electroless nickel processes. Copper and nickel electroless plating are the most prevalent electroless 

plating operations seen at facilities performing proposed MP&M operations. 

C.5 Metal-Bearing Wastewater 

All of the wastewaters generated in proposed MP&M operations can contain metals, 

including the wastewaters described in the previous subsections. Section C.5.1 discusses proposed 

MP&M operations not presented in the previous subsections that generate metal-bearing wastewater 

and presents pollutant concentration data for the process water and rinse water for those operations. 

C-6
Appendix C - Wastewater Characteristics 

Section C.5.2 presents pollutant concentration data for the influent to chemical precipitation systems 

used to treat metal-bearing wastewater. 

C.5.1 Process Water and Rinse Water 

Table C-7 lists the proposed MP&M operations that generate metal-bearing 

wastewater and presents the number of samples of process water and rinse water collected and 

analyzed in EPA’s sampling program for each unit operation. 

Facilities performing proposed MP&M operations typically use metals in the process 

baths for unit operations such as electroplating and stripping. Tables C-8 and C-9 summarize the 

pollutant concentration data for process water and rinse water, respectively, collected during the 

MP&M sampling program for unit operations generating metal-bearing wastewater. As shown in the 

tables, the metal priority pollutants most frequently detected in samples of process water were copper, 

zinc, chromium, nickel, and lead. Nonconventional metal pollutants frequently detected include iron, 

magnesium, boron, barium, manganese, and aluminum. The process water and rinses also typically 

contained oil and grease, total suspended solids, and low concentrations of organic pollutants. 

C.5.2 Influent to the Chemical Precipitation Treatment Systems 

Typically, facilities performing proposed MP&M operations segregate their 

wastewaters by type and treat them in preliminary treatment systems. After preliminary treatment, 

facilities performing proposed MP&M operations usually commingle the wastewater with other process 

wastewater and treat the commingled wastewater in an end-of-pipe treatment system. Generally, the 

end-of-pipe treatment consists of chemical precipitation and sedimentation (see Section 8.5.1). When 

high concentrations of metals are present in the wastewater, sites may use preliminary batch chemical 

precipitation and sedimentation to ensure that the high concentrations do not cause an upset in the endof-pipe treatment system. Facilities performing proposed MP&M operations may also contract haul 

concentrated baths to centralized waste treatment facilities. Table C-10 summarizes the pollutant 

concentration data obtained from sampling the influent to end-of-pipe chemical precipitation with 

sedimentation and chemical precipitation with membrane filtration systems for metal-bearing 

wastewater. 

C-7
Appendix C - Wastewater Characteristics 

Table C-7 

Number of Process Water and Rinse Water Samples Collected and 

Analyzed for Unit Operations That Generate Metal-Bearing Wastewater 

Unit Operation 

No. of Process Water 

Samples a 

No. of Rinse Water 

Samples a 

Abrasive Jet Machining 

Acid Treatment without Chromium 

Anodizing without Chromium 

Carbon Black Deposition 

Chemical Milling 

Chemical Conversion Coating without Chromium 

Electrochemical Machining 

Electroless Plating 

Electrolytic Cleaning 

Electroplating without Chromium or Cyanide 

Electropolishing 

Painting-immersion (Including Electrophoretic, "E-coat") 

Photo Image Developing 

Photoresist Applications 

Plasma Arc Machining 

Salt Bath Descaling 

Solder Flux Cleaning 

Solder Fusing 

Stripping (paint) 

Stripping (metallic coating) 

3 

27 

4 

2 

4 

24 

1 

9 

9 

24 

1 

1 

5 

0 

1 

0 

1 

0 

6 

9 

3 

65 

3 

3 

9 

59 

2 

28 

17 

48 

1 

6 

11 

0 

0 

4 

4 

3 

4 

12 

Source: MP&M Sampling Program.

a

Unit operations for which no samples were collected are rarely performed or were not observed at facilities

performing proposed MP&M operations.

C-8
Appendix C - Wastewater Characteristics 

Table C-8 

Process Water Pollutant Concentration Data for Unit Operations That 

Generate Metal-Bearing Wastewater 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants 

1,1-Dichloroethane 41 0 NA NA NA NA 

1,1-Dichloroethene 41 0 NA NA NA NA 

1,1,1-Trichloroethane 41 0 NA NA NA NA 

2-Nitrophenol 40 1 2.15 2.15 2.15 2.15 

2,4-Dinitrophenol 36 1 335 335 335 335 

2,4-Dimethylphenol 40 1 0.167 0.167 0.167 0.167 

2,6-Dinitrotoluene 41 2 0.605 6.98 3.79 3.79 

4-Chloro-3-Methylphenol 39 0 NA NA NA NA 

4-Nitrophenol 39 1 14.1 14.1 14.1 14.1 

Acenaphthene 41 0 NA NA NA NA 

Acrolein 40 1 0.591 0.591 0.591 0.591 

Anthracene 41 0 NA NA NA NA 

Bis(2-ethylhexyl) Phthalate 41 12 0.012 18.2 3.10 0.291 

Butyl Benzyl Phthalate 41 0 NA NA NA NA 

Chlorobenzene 41 4 0.011 1.56 0.414 0.041 

Chloroethane 41 0 NA NA NA NA 

Chloroform 41 3 0.012 0.218 0.080 0.012 

Di-n-octyl Phthalate 41 2 0.639 1.42 1.03 1.03 

Di-n-butyl Phthalate 41 0 NA NA NA NA 

Dimethyl Phthalate 41 0 NA NA NA NA 

Ethylbenzene 41 2 0.020 2.91 1.46 1.46 

Fluoranthene 41 0 NA NA NA NA 

Fluorene 41 0 NA NA NA NA 

Isophorone 41 0 NA NA NA NA 

Methylene Chloride 41 3 0.011 0.173 0.080 0.056 

N-Nitrosodimethylamine 41 1 6.67 6.67 6.67 6.67 

N-Nitrosodiphenylamine 41 0 NA NA NA NA 

C-9
Appendix C - Wastewater Characteristics 

Table C-8 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants (continued) 

Naphthalene 41 2 0.024 0.208 0.116 0.116 

Phenanthrene 41 0 NA NA NA NA 

Phenol 41 5 0.024 1,044 216 2.00 

Pyrene 41 0 NA NA NA NA 

Tetrachloroethene 41 0 NA NA NA NA 

Toluene 41 2 0.014 0.032 0.023 0.023 

Trichloroethene 41 6 0.010 0.058 0.026 0.023 

Metal Priority Pollutants 

Antimony 129 50 0.002 3.56 0.359 0.090 

Arsenic 129 62 0.001 16.4 0.655 0.080 

Beryllium 129 39 0.001 3.87 0.270 0.030 

Cadmium 132 74 0.002 57,100 791 0.203 

Chromium 132 115 0.007 108,000 1,952 1.87 

Copper 132 124 0.009 141,000 2,885 7.24 

Lead 132 83 0.002 4,880 120 2.62 

Mercury 129 25 0.0003 0.032 0.003 0.0009 

Nickel 131 109 0.007 84,623 3,091 5.89 

Selenium 129 30 0.001 8.00 0.659 0.051 

Silver 132 57 0.001 14.4 0.503 0.075 

Thallium 129 18 0.001 3.48 0.411 0.019 

Zinc 131 118 0.005 53,200 2,750 15.7 

Conventional Pollutants 

BOD 5-Day (Carbonaceous) 33 22 4.29 18,600 4,537 1,600 

Oil and Grease (as HEM) 53 27 1.08 2,400 271 68.9 

Total Suspended Solids 127 119 5.00 110,000 2,338 154 

Nonconventional Organic Pollutants 

1-Bromo-2-Chlorobenzene 41 4 0.012 0.978 0.382 0.268 

1-Bromo-3-Chlorobenzene 41 4 0.031 0.490 0.193 0.126 

1-Methylfluorene 41 0 NA NA NA NA 

1-Methylphenanthrene 41 0 NA NA NA NA 

1,4-Dioxane 41 3 0.365 2.80 1.36 0.920 

C-10
Appendix C - Wastewater Characteristics 

Table C-8 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

2-Butanone 40 12 0.070 26.1 4.61 1.43 

2-Hexanone 41 1 5.02 5.02 5.02 5.02 

2-Isopropylnaphthalene 41 0 NA NA NA NA 

2-Methylnaphthalene 41 1 0.220 0.220 0.220 0.220 

2-Propanone 41 27 0.052 250 11.3 0.485 

3,6-Dimethylphenanthrene 41 0 NA NA NA NA 

4-Methyl-2-Pentanone 41 5 0.052 159 32.0 0.187 

Acetophenone 41 0 NA NA NA NA 

Alpha-terpineol 41 0 NA NA NA NA 

Aniline 41 4 0.015 0.335 0.145 0.115 

Benzoic Acid 41 8 0.051 8,098 1,037 27.2 

Benzyl Alcohol 41 4 0.012 0.278 0.103 0.061 

Biphenyl 41 0 NA NA NA NA 

Carbon Disulfide 41 1 0.053 0.053 0.053 0.053 

Dibenzofuran 41 1 0.140 0.140 0.140 0.140 

Dibenzothiophene 41 0 NA NA NA NA 

Diphenyl Ether 41 0 NA NA NA NA 

Diphenylamine 41 0 NA NA NA NA 

Hexanoic Acid 41 5 0.012 31.5 9.12 0.763 

Isobutyl Alcohol 41 0 NA NA NA NA 

m-Xylene 14 2 0.020 5.06 2.54 2.54 

m+p Xylene 27 0 NA NA NA NA 

Methyl Methacrylate 41 4 0.181 0.797 0.586 0.682 

n-Decane 41 1 3.51 3.51 3.51 3.51 

n-Docosane 41 1 0.142 0.142 0.142 0.142 

n-Dodecane 41 1 1.27 1.27 1.27 1.27 

n-Eicosane 41 1 0.030 0.030 0.030 0.030 

n-Hexacosane 41 1 0.106 0.106 0.106 0.106 

n-Hexadecane 41 0 NA NA NA NA 

n-Nitrosopiperidine 41 0 NA NA NA NA 

n-Octacosane 41 1 0.071 0.071 0.071 0.071 

C-11
Appendix C - Wastewater Characteristics 

Table C-8 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

n-Octadecane 41 0 NA NA NA NA 

n-Tetracosane 41 1 0.097 0.097 0.097 0.097 

n-Tetradecane 41 0 NA NA NA NA 

n-Triacontane 41 1 0.082 0.082 0.082 0.082 

n,n-Dimethylformamide 41 3 0.032 0.123 0.064 0.036 

o-cresol 41 2 0.023 0.195 0.109 0.109 

o-xylene 27 0 NA NA NA NA 

o+p Xylene 14 2 0.910 2.01 1.46 1.46 

p-Cymene 41 0 NA NA NA NA 

p-Cresol 41 3 0.011 0.513 0.192 0.054 

Pyridine 41 0 NA NA NA NA 

Styrene 41 0 NA NA NA NA 

Trichlorofluoromethane 41 0 NA NA NA NA 

Tripropyleneglycol Methyl Ether 41 2 0.245 1.45 0.848 0.848 

Nonconventional Metal Pollutants 

Aluminum 131 107 0.042 34,900 1,112 3.39 

Barium 129 102 0.001 259 4.24 0.096 

Boron 130 106 0.022 17,800 659 1.32 

Calcium 129 125 0.054 2,250 130 23.4 

Cobalt 129 81 0.003 4,700 73.5 0.660 

Gold 1 1 0.392 0.392 0.392 0.392 

Iron 131 122 0.011 374,000 7,051 13.4 

Magnesium 129 106 0.085 960 73.8 15.2 

Manganese 132 110 0.001 4,790 106 0.767 

Molybdenum 130 87 0.001 197 5.40 0.237 

Sodium 129 125 1.25 383,000 17,905 1,164 

Tin 132 82 0.004 22,670 930 0.984 

Titanium 129 84 0.002 13,250 180 0.303 

Vanadium 129 68 0.001 1,495 23.5 0.066 

Yttrium 129 24 0.001 0.900 0.115 0.038 

C-12
Appendix C - Wastewater Characteristics 

Table C-8 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Other Nonconventional Pollutants 

Ammonia as Nitrogen 66 53 0.060 44,800 2,922 10.0 

Chemical Oxygen Demand (COD) 60 56 83.0 600,000 32,426 7,400 

Chloride 69 53 1.00 328,300 20,901 240 

Cyanide 10 7 0.027 0.510 0.153 0.120 

Fluoride 69 58 0.140 55,500 1,034 5.10 

Hexavalent Chromium 36 5 0.008 0.430 0.104 0.025 

Sulfate 105 89 1.56 755,000 36,919 808 

Total Dissolved Solids 125 123 87.0 1,000,000 135,033 64,100 

Total Kjeldahl Nitrogen 49 42 0.480 40,000 2,584 42.0 

Total Organic Carbon (TOC) 49 48 4.71 54,000 7,492 1,245 

Total Petroleum Hydrocarbons 

(as SGT-HEM) 51 9 6.00 352 88.2 14.1 

Total Phosphorus 30 21 0.020 11,000 945 11.0 

Total Recoverable Phenolics 52 35 0.006 135 7.78 0.330 

Total Sulfide 17 0 NA NA NA NA 

Source: MP&M Sampling Program.

a

Due to budgetary constraints, EPA did not analyze all samples for all pollutants.

NA - Not applicable.

C-13
Appendix C - Wastewater Characteristics 

Table C-9 

Rinse Water Pollutant Concentration Data for Unit Operations That 

Generate Metal-Bearing Wastewater 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants 

1,1-Dichloroethane 91 0 NA NA NA NA 

1,1-Dichloroethene 91 0 NA NA NA NA 

1,1,1-Trichloroethane 91 0 NA NA NA NA 

2-Nitrophenol 89 0 NA NA NA NA 

2,4-Dimethylphenol 91 0 NA NA NA NA 

2,4-Dinitrophenol 85 0 NA NA NA NA 

2,6-Dinitrotoluene 91 0 NA NA NA NA 

4-Chloro-3-Methylphenol 91 0 NA NA NA NA 

4-Nitrophenol 88 0 NA NA NA NA 

Acenaphthene 91 0 NA NA NA NA 

Acrolein 87 0 NA NA NA NA 

Anthracene 91 0 NA NA NA NA 

Bis(2-ethylhexyl) Phthalate 91 10 0.011 0.281 0.064 0.019 

Butyl Benzyl Phthalate 91 0 NA NA NA NA 

Chlorobenzene 91 0 NA NA NA NA 

Chloroethane 91 0 NA NA NA NA 

Chloroform 91 49 0.010 0.063 0.025 0.022 

Di-n-octyl Phthalate 91 1 0.013 0.013 0.013 0.088 

Di-n-butyl Phthalate 91 6 0.014 0.190 0.098 0.013 

Dimethyl Phthalate 91 1 0.021 0.021 0.021 0.021 

Ethylbenzene 91 2 0.021 0.028 0.024 0.024 

Fluoranthene 91 0 NA NA NA NA 

Fluorene 91 0 NA NA NA NA 

Isophorone 91 0 NA NA NA NA 

Methylene Chloride 91 1 0.011 0.011 0.011 0.011 

n-Nitrosodiphenylamine 91 0 NA NA NA NA 

n-Nitrosodimethylamine 91 0 NA NA NA NA 

Naphthalene 91 1 0.021 0.021 0.021 0.021 

C-14
Appendix C - Wastewater Characteristics 

Table C-9 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants (continued) 

Phenanthrene 91 0 NA NA NA NA 

Phenol 90 5 0.011 2.00 0.417 0.024 

Pyrene 91 0 NA NA NA NA 

Tetrachloroethene 91 0 NA NA NA NA 

Toluene 91 0 NA NA NA NA 

Trichloroethene 91 3 0.010 0.018 0.015 0.015 

Metal Priority Pollutants 

Antimony 261 42 0.002 0.158 0.026 0.011 

Arsenic 261 63 0.001 0.308 0.018 0.006 

Beryllium 261 13 0.001 0.059 0.010 0.001 

Cadmium 265 62 0.002 6.93 0.310 0.011 

Chromium 265 155 0.002 21.6 0.761 0.052 

Copper 265 235 0.003 507 14.0 0.154 

Lead 265 90 0.002 81.0 3.52 0.066 

Mercury 261 25 0.0002 0.004 0.001 0.0004 

Nickel 263 172 0.002 437 20.0 0.115 

Selenium 261 39 0.001 0.412 0.019 0.003 

Silver 265 55 0.001 0.962 0.047 0.010 

Thallium 261 19 0.001 0.039 0.006 0.001 

Zinc 265 187 0.002 13,700 168 0.019 

Conventional Pollutants 

BOD 5-Day (Carbonaceous) 86 39 1.07 11,400 505 40.0 

Oil and Grease (as HEM) 130 34 1.12 114 17.2 10.4 

Total Suspended Solids 260 174 2.00 6,920 132 20.0 

Nonconventional Organic Pollutants 

1-Bromo-2-Chlorobenzene 91 0 NA NA NA NA 

1-Bromo-3-Chlorobenzene 91 0 NA NA NA NA 

1-Methylfluorene 91 0 NA NA NA NA 

1-Methylphenanthrene 91 0 NA NA NA NA 

1,4-Dioxane 91 1 0.196 0.196 0.196 0.196 

2-Butanone 89 10 0.066 0.550 0.214 0.133 

C-15
Appendix C - Wastewater Characteristics 

Table C-9 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

2-Hexanone 91 0 NA NA NA NA 

2-Isopropylnaphthalene 91 0 NA NA NA NA 

2-Methylnaphthalene 91 0 NA NA NA NA 

2-Propanone 91 13 0.052 11.5 1.51 0.097 

3,6-Dimethylphenanthrene 91 0 NA NA NA NA 

4-Methyl-2-Pentanone 91 2 0.190 17.4 8.80 8.80 

Acetophenone 91 0 NA NA NA NA 

Alpha-Terpineol 91 0 NA NA NA NA 

Aniline 91 0 NA NA NA NA 

Benzoic Acid 91 6 0.108 4.31 1.21 0.659 

Benzyl Alcohol 91 2 0.014 0.014 0.014 0.014 

Biphenyl 91 0 NA NA NA NA 

Carbon Disulfide 91 0 NA NA NA NA 

Dibenzofuran 91 0 NA NA NA NA 

Dibenzothiophene 91 0 NA NA NA NA 

Diphenyl Ether 91 1 0.013 0.013 0.013 0.013 

Diphenylamine 91 0 NA NA NA NA 

Hexanoic Acid 91 1 0.015 0.015 0.015 0.015 

Isobutyl Alcohol 91 0 NA NA NA NA 

m-Xylene 20 2 0.036 0.076 0.056 0.056 

m+p Xylene 71 0 NA NA NA NA 

Methyl Methacrylate 91 0 NA NA NA NA 

n-Decane 91 0 NA NA NA NA 

n-Docosane 91 1 0.012 0.012 0.012 0.012 

n-Dodecane 91 0 NA NA NA NA 

n-Eicosane 91 0 NA NA NA NA 

n-Hexacosane 91 2 0.037 0.434 0.236 0.236 

n-Hexadecane 91 1 0.057 0.057 0.057 0.057 

n-Nitrosopiperidine 91 0 NA NA NA NA 

n-Octacosane 91 1 0.041 0.041 0.041 0.041 

n-Octadecane 91 0 NA NA NA NA 

C-16
Appendix C - Wastewater Characteristics 

Table C-9 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

n-Tetracosane 91 1 0.018 0.018 0.018 0.018 

n-Tetradecane 91 1 0.221 0.221 0.221 0.221 

n-Triacontane 91 2 0.030 0.477 0.253 0.253 

n,n-dimethylformamide 91 2 0.026 0.115 0.071 0.071 

o-Cresol 91 0 NA NA NA NA 

o-Xylene 71 0 NA NA NA NA 

o+p Xylene 20 2 0.042 0.113 0.077 0.077 

p-Cymene 91 0 NA NA NA NA 

p-Cresol 91 0 NA NA NA NA 

Pyridine 91 0 NA NA NA NA 

Styrene 91 0 NA NA NA NA 

Trichlorofluoromethane 91 0 NA NA NA NA 

Tripropyleneglycol Methyl Ether 91 1 8.48 8.48 8.48 8.48 

Nonconventional Metal Pollutants 

Aluminum 263 161 0.022 76.9 1.61 0.192 

Barium 261 207 0.001 2.90 0.064 0.028 

Boron 263 179 0.016 363 4.38 0.180 

Calcium 261 255 0.033 361 30.7 23.0 

Cobalt 261 58 0.001 12.4 0.945 0.014 

Gold 2 1 6.88 6.88 6.88 6.88 

Iron 263 196 0.003 2,810 58.8 0.334 

Magnesium 261 240 0.067 130 9.22 7.56 

Manganese 265 171 0.001 68.3 1.52 0.024 

Molybdenum 263 80 0.002 13.4 0.341 0.017 

Sodium 261 257 0.277 55,800 710 60.0 

Tin 265 105 0.002 828 11.6 0.052 

Titanium 261 80 0.001 18.1 0.762 0.015 

Vanadium 261 35 0.001 1.10 0.108 0.010 

Yttrium 261 8 0.001 0.004 0.002 0.001 

C-17
Appendix C - Wastewater Characteristics 

Table C-9 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Other Nonconventional Pollutants 

Amenable Cyanide 3 3 0.340 1.97 1.05 0.830 

Ammonia as Nitrogen 114 68 0.050 1,190 91.2 1.58 

Chemical Oxygen Demand (COD) 107 84 5.20 20,400 614 44.0 

Chloride 77 76 1.20 5,000 219 26.0 

Cyanide 12 9 0.028 87.0 10.7 0.830 

Fluoride 77 68 0.110 60.0 3.65 0.990 

Hexavalent Chromium 90 17 0.011 0.063 0.023 0.019 

Sulfate 163 158 1.64 7,120 306 54.0 

Total Dissolved Solids 258 258 10.0 132,000 2,469 550 

Total Kjeldahl Nitrogen 79 44 0.100 395 28.0 8.69 

Total Organic Carbon (TOC) 129 114 1.16 6,110 230 12.0 

Total Petroleum Hydrocarbons 

(as SGT-HEM) 129 7 5.25 13.0 7.86 7.75 

Total Phosphorus 28 21 0.026 290 30.9 1.40 

Total Recoverable Phenolics 100 42 0.005 2.85 0.192 0.013 

Total Sulfide 45 0 NA NA NA NA 

Source: MP&M Sampling Data.

a

Due to budgetary constraints, EPA did not analyze all samples for all pollutants.

NA - Not applicable.

C-18
Appendix C - Wastewater Characteristics 

Table C-10 

Pollutant Concentration Data for the Influent 

to Chemical Precipitation Systems 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants 

1,1-Dichloroethane 171 0 NA NA NA NA 

1,1-Dichloroethylene 171 2 0.011 0.748 0.379 0.379 

1,1,1-Trichloroethane 171 6 0.019 0.084 0.053 0.053 

2,4-Dimethylphenol 162 0 NA NA NA NA 

2,4-Dinitrophenol 167 2 0.111 1.66 0.885 0.885 

2,6-Dinitrotoluene 178 0 NA NA NA NA 

2-Nitrophenol 177 0 NA NA NA NA 

4-Chloro-m-Cresol 176 9 0.011 1.14 0.183 0.076 

4-Nitrophenol 172 0 NA NA NA NA 

Acenaphthene 178 0 NA NA NA NA 

Acrolein 141 0 NA NA NA NA 

Anthracene 178 1 0.104 0.104 0.104 0.104 

Benzyl Butyl Phthalate 178 2 0.009 0.010 0.009 0.009 

Bis(2-ethylhexyl) Phthalate 178 43 0.008 0.298 0.052 0.030 

Chlorobenzene 171 0 NA NA NA NA 

Chloroethane 171 0 NA NA NA NA 

Chloroform 171 68 0.010 0.824 0.097 0.031 

Di-n-butyl Phthalate 178 6 0.007 0.066 0.030 0.018 

Di-n-octyl Phthalate 178 1 0.012 0.012 0.012 0.012 

Dimethyl Phthalate 175 1 0.0004 0.0004 0.0004 0.0004 

Ethylbenzene 171 5 0.006 0.335 0.074 0.010 

Fluoranthene 178 0 NA NA NA NA 

Fluorene 178 1 0.045 0.045 0.045 0.045 

Isophorone 175 0 NA NA NA NA 

Methylene Chloride 171 10 0.008 0.172 0.043 0.023 

n-Nitrosodimethylamine 175 2 0.065 0.070 0.067 0.067 

n-Nitrosodiphenylamine 174 0 NA NA NA NA 

C-19
Appendix C - Wastewater Characteristics 

Table C-10 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Organic Priority Pollutants (continued) 

Naphthalene 178 3 0.012 0.054 0.035 0.038 

Phenanthrene 178 3 0.041 0.112 0.071 0.060 

Phenol 179 34 0.010 0.634 0.070 0.030 

Pyrene 178 0 NA NA NA NA 

Tetrachloroethene 171 8 0.015 1.11 0.306 0.081 

Toluene 171 6 0.009 2.77 0.534 0.019 

Trichloroethylene 171 3 0.019 0.023 0.021 0.021 

Metal Priority Pollutants 

Antimony 261 86 0.002 1.13 0.058 0.018 

Arsenic 268 109 0.001 0.530 0.025 0.009 

Beryllium 268 64 0.0002 3.23 0.228 0.004 

Cadmium 457 170 0.0003 323 4.25 0.039 

Chromium 469 444 0.001 1,350 9.92 0.676 

Copper 472 467 0.010 665 13.9 0.480 

Lead 465 376 0.002 159 3.44 0.416 

Mercury 266 52 0.00003 0.012 0.001 0.0003 

Nickel 467 457 0.012 2,101 18.3 1.47 

Selenium 265 42 0.001 0.090 0.018 0.006 

Silver 460 222 0.001 4.94 0.406 0.036 

Thallium 265 26 0.001 0.112 0.011 0.002 

Zinc 472 459 0.009 636 33.6 3.65 

Conventional Pollutants 

BOD 5-Day (Carbonaceous) 133 86 2.40 609 64.4 26.0 

Oil and Grease (as HEM) 236 159 0.570 32,000 428 12.1 

Total Suspended Solids 334 314 4.00 11,400 803 120 

Nonconventional Organic Pollutants 

1,4-Dioxane 166 6 0.033 2.41 0.788 0.584 

1-Bromo-2-Chlorobenzene 169 2 0.011 0.012 0.012 0.012 

1-Bromo-3-Chlorobenzene 169 5 0.026 0.067 0.045 0.038 

1-Methylfluorene 169 2 0.111 0.189 0.150 0.150 

1-Methylphenanthrene 169 2 0.092 0.181 0.136 0.136 

C-20
Appendix C - Wastewater Characteristics 

Table C-10 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

2-Butanone 166 13 0.056 2.45 0.668 0.151 

2-Hexanone 166 0 NA NA NA NA 

2-Isopropylnaphthalene 169 0 NA NA NA NA 

2-Methylnaphthalene 173 2 0.076 0.205 0.140 0.140 

2-Propanone 166 87 0.051 16.7 0.822 0.137 

3,6-Dimethylphenanthrene 169 2 0.019 0.062 0.041 0.041 

4-Methyl-2-Pentanone 166 10 0.120 1.36 0.308 0.181 

Acetophenone 169 2 0.010 0.011 0.011 0.011 

Alpha-terpineol 162 5 0.013 0.087 0.051 0.054 

Aniline 173 6 0.013 0.052 0.023 0.017 

Benzoic Acid 173 69 0.011 34.8 3.27 0.229 

Benzyl Alcohol 173 9 0.005 0.080 0.028 0.013 

Biphenyl 169 1 0.011 0.011 0.011 0.011 

Carbon Disulfide 166 10 0.016 3.92 0.505 0.058 

Dibenzofuran 173 0 NA NA NA NA 

Dibenzothiophene 169 2 0.015 0.025 0.020 0.020 

Diphenyl Ether 169 0 NA NA NA NA 

Diphenylamine 165 1 0.033 0.033 0.033 0.033 

Hexanoic Acid 169 23 0.010 0.461 0.053 0.017 

Isobutyl Alcohol 166 0 NA NA NA NA 

m+p Xylene 96 0 NA NA NA NA 

m-Xylene 70 1 0.016 0.016 0.016 0.016 

Methyl Methacrylate 166 3 0.019 0.039 0.030 0.032 

n-Decane 166 3 0.029 0.031 0.031 0.031 

n-Docosane 169 6 0.011 0.026 0.016 0.013 

n-Dodecane 168 6 0.044 0.772 0.269 0.101 

n-Eicosane 169 17 0.010 0.181 0.034 0.020 

n-Hexacosane 169 12 0.012 0.041 0.027 0.028 

n-Hexadecane 169 22 0.010 0.631 0.085 0.026 

n-Nitrosopiperidine 169 0 NA NA NA NA 

n-octacosane 169 3 0.018 0.036 0.030 0.035 

C-21
Appendix C - Wastewater Characteristics 

Table C-10 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Nonconventional Organic Pollutants (continued) 

n-Octadecane 169 25 0.011 0.493 0.072 0.024 

n-Tetracosane 169 7 0.012 0.032 0.019 0.017 

n-Tetradecane 169 14 0.016 1.01 0.174 0.058 

n-Triacontane 169 4 0.011 0.031 0.019 0.017 

n,n-Dimethylformamide 169 22 0.011 0.581 0.094 0.044 

o+p Xylene 70 3 0.013 0.023 0.017 0.014 

o-Cresol 169 0 NA NA NA NA 

o-Xylene 96 0 NA NA NA NA 

p-Cresol 169 10 0.013 0.030 0.019 0.017 

p-Cymene 169 3 0.015 0.054 0.030 0.02 

Pyridine 169 0 NA NA NA NA 

Styrene 173 8 0.010 0.188 0.041 0.022 

Trichlorofluoromethane 171 6 0.029 0.109 0.045 0.033 

Tripropyleneglycol Methyl 

Ether 169 23 0.064 5.21 1.83 1.05 

Nonconventional Metal Pollutants 

Aluminum 268 246 0.055 132 8.68 2.38 

Barium 266 241 0.003 9.91 0.251 0.058 

Boron 253 232 0.057 81.3 3.53 0.787 

Calcium 268 268 3.40 1,220 83.0 34.9 

Cobalt 264 121 0.001 25.8 0.757 0.019 

Gold 20 10 0.013 0.150 0.056 0.038 

Iron 268 268 0.022 3,880 111 5.38 

Magnesium 268 263 0.349 3,360 74.5 8.88 

Manganese 453 452 0.001 109 4.04 0.870 

Molybdenum 453 347 0.001 3.06 0.175 0.037 

Sodium 268 268 17.7 9,600 460 211 

Tin 442 341 0.004 1,440 14.2 0.199 

Titanium 253 189 0.002 76.4 1.53 0.048 

Vanadium 264 87 0.002 1.19 0.052 0.014 

Yttrium 253 60 0.001 0.085 0.010 0.004 

C-22
Appendix C - Wastewater Characteristics 

Table C-10 (Continued) 

Pollutant 

No. of Samples 

Analyzeda 

No. of 

Detects 

Concentration (mg/L) 

Minimum Maximum Mean Median 

Other Nonconventional Pollutants 

Ammonia as Nitrogen 113 110 0.040 320 25.9 5.61 

Chemical Oxygen Demand 

(COD) 203 194 1.50 13,000 532 122 

Chloride 78 75 4.50 9,500 338 140 

Cyanide 32 12 0.008 0.096 0.022 0.012 

Fluoride 78 77 0.130 100 4.54 1.50 

Hexavalent Chromium 133 50 0.010 21.0 0.771 0.060 

Sulfate 177 170 18.0 6,125 469 318 

Total Dissolved Solids 263 263 19.0 34,000 2,325 1,103 

Total Kjeldahl Nitrogen 83 80 0.110 160 14.9 6.66 

Total Organic Carbon (TOC) 175 146 3.57 400 73.5 46.9 

Total Petroleum Hydrocarbons 

(as SGT-HEM) 143 52 5.00 93.0 20.4 10.0 

Total Phosphorus 84 82 0.020 525 28.1 5.20 

Total Recoverable Phenolics 188 110 0.006 13.0 0.387 0.047 

Total Sulfide 95 31 0.150 28.0 5.20 1.03 

Ziram 5 3 0.177 0.448 0.291 0.247 

Source: MP&M Sampling Program.

a

Due to budgetary constraints, EPA did not analyze all samples for all pollutants.

NA - Not applicable.

C-23
Appendix D - Pollution Prevention and Water Conservation Practices 

Appendix D


POLLUTION PREVENTION AND WATER CONSERVATION PRACTICES

Appendix D - Pollution Prevention and Water Conservation Practices 

Appendix D 

POLLUTION PREVENTION AND WATER CONSERVATION PRACTICES 

EPA observed a number of pollution prevention and water conservation practices 

during site visits and sampling episodes, and MP&M surveys provided additional information on 

these practices (see Sections 3.0 and 8.0). Some common pollution prevention and water 

conservation methods for surface treatment include drag-out tanks, countercurrent cascade 

rinsing, manual and automatic rinse water shut-off, timed rinses, flow restrictors, conductivity 

meters, and in-process ion exchange and water recycle. In this appendix, EPA describes some of 

these common pollution prevention and water conservation methods used by facilities evaluated 

for the final rule (“MP&M facilities”) as a measure to assist a broader audience to achieve 

improved environmental performance and compliance, pollution prevention through source 

reduction, and continual improvement. EPA is not promulgating or requiring any of these 

methods or mass-based limitations and standards in the MP&M effluent guidelines (see 

Section 15.0). The final limitations and standards in the MP&M effluent guidelines are 

concentration based and may be achieved using any method compliant with EPA 

regulations. 

Pollution Prevention and Water Conservation Practices for Surface 

Treatment 

The Agency identified four categories of pollution prevention and water 

conservation practices and technologies that can be applied to reduce rinse-water use: drag-out 

reduction and/or drag-out recovery methods; improved rinse tank design and rinsing 

configurations; rinse-water use control devices; and, metal recovery and rinse-water reuse 

technologies. Surface treatment rinses include those following acid and alkaline treatment, 

anodizing, electroplating, electroless plating, and chemical conversion coating. Rinsing dilutes 

and removes the chemical film of drag-out remaining on parts and racks after processing in a 

chemical bath. In addition to conserving water use, some of these methods (especially those that 

affect drag-out and recover chemicals) also conserve raw materials, reduce pollutant loadings to 

wastewater treatment systems, and reduce treatment reagent requirements and sludge production. 

Within each of these categories are several specific practices and technologies. Table D-1 

presents examples of these practices and technologies, as well as their applicability to the MP&M 

operations.1 Table D-2 provides descriptions of these practices. 

1

EPA evaluated a number of unit operations for the May 1995 proposal, January 2001 proposal, and June 2002 

NODA (see Tables 4-3 and 4-4). However, EPA selected a subset of these unit operations for regulation in the final 

rule (see Section 1.0). For this Section, the term “proposed MP&M operations” means those operations evaluated for 

the two proposals, NODA, and final rule. The term “final MP&M operations” means those operations defined as 

“oily operations” (see Section 1.0, 40 CFR 438.2(f), and Appendix B to Part 438) and regulated by the final rule. 

D-1 

D.1 
Appendix D - Pollution P

Table D-1


Potential Water Conservation Methods for Surface Treatment Rinses


D-2


Practice 

Alkaline 

Clean 

Acid 

Clean 

Hexavalent 

Chromium 

Trivalent 

Chromium 

Cadmium 

Zinc 

Cyanide 

Cadmium Zinc NonCyanide Acid Copper Copper Cyanide 

Watts, 

Woods, 

Other 

Nickels 

Electroless 

Nickel 

Silver 

Cyanide 

Gold 

Cyanide 

Lead, 

LeadTin Tin 

Drag-out Reduction and Recovery Fog or spray rinsing 

over tank (110° F or 

higher) 

� � � � � � � �a 

Controlled slow 

withdrawal 

� � � � � � � � � � � � � � 

Addition of wetting 

agent (when 

compatible) 

� � � � � � � � � � � � 

Positioning work 

piece 

� � � � � � � � � � � � � � 

Long drip time � � � � � � � � � � � � Drip shield � � � � � � � � � � � � � � Air knife � � � � � � � � Drag-out tank (heated) 

� � � � � � � � � � � � � 

Drag-in/out tank � � � � � � � � � � � � � Lowest concentration � � � � � � � � � � � � � � Highest temperature � � � � � � � � � � � � � Rinse Tank Design and Innovative Configuration Countercurrent rinse � � � � � � � � � � � � � � 

Cascading rinse 

(cleaning) 

� �

Spray rinse � � � � � � � � � � � � � � 

Good tank designb � � � � � � � � � � � � � � 

Rinse Water Use Control Flow restrictors � � � � � � � � � � � � � � Timer controls � � � � � � � � � � � � � � Conductivity controls � � � � � � � � � � � � � � 
Appendix D - Pollution P

Table D-1 (Continued)


Practice 

Alkaline 

Clean 

Acid 

Clean 

Hexavalent 

Chromium 

Trivalent 

Chromium 

Cadmium 

Zinc 

Cyanide 

Cadmium Zinc NonCyanide Acid Copper Copper Cyanide 

Watts, 

Woods, 

Other 

Nickels 

Electroless 

Nickel 

Silver 

Cyanide 

Gold 

Cyanide 

Lead, 

LeadTin Tin 

Metal Recovery and Rinse Water Reuse Technologies Evaporatorc � � � � � � � � � � � � Ion exchangec � � � � � � � � � �Electrolytic 

Recovery 

� � � � � � � �

Electrodialysisc � � � �Reverse osmosisc � � � � � � � 

Source: MP&M Site Visits, MP&M Surveys, Technical Literature.
aAlkaline tin only.
bFor example, air or other agitation, minimum size, and inlet, outlet location opposite ends.
cOnly common applications of this technology are checked.


D-3

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-2 

Descriptions of Pollution Prevention 

and Water Conservation Practices and Technologies 

Practice or 

Technology Description 

Air Knife Air knives are usually installed over a process tank or drip shield and are designed to 

remove drag-out by blowing it off the surface of parts and racks. Drag-out is routed back 

to the process tank. Air knives are more effective with flat parts. They cannot be used to 

dry surfaces that passivate or stain due to oxidation. 

Cascade Rinsing Cascade rinsing is a method of reusing rinse water. Water from one rinsing operation is 

plumbed to another, less critical one before being discharged to treatment. Some rinse 

waters acquire chemical properties, such as low pH, that make them desirable for reuse in 

specific rinse systems. This is generally referred to as reactive rinsing. 

Conductivity 

Controller 

Conductivity probes measure the conductivity of water in a rinse tank to regulate the flow 

of fresh water into the rinse system. Conductivity controllers consist of a controller, a 

meter with adjustable set points, a probe that is placed in the rinse tank, and a solenoid 

valve. As parts are rinsed, dissolved solids are added to the water in the rinse tank, raising 

the conductivity of the water. When conductivity reaches the set point, the solenoid valve 

opens to allow make-up water to enter the tank. When the conductivity falls below the set 

point, the valve shuts to discontinue the make-up water. 

In theory, conductivity control of rinse flow is a precise method of maintaining optimum 

rinsing conditions in intermittently used rinse operations. In practice, conductivity 

controllers work best with deionized rinse water. Incoming water conductivity may vary 

day to day and season to season, which forces frequent set-point adjustments. Suspended 

solids and nonionic contaminants (e.g., oil) are not detected by the conductivity probe and 

can cause inadequate rinsing. 

Countercurrent 

Cascade Rinsing 

Countercurrent cascade rinsing refers to a series of consecutive rinse tanks that are 

plumbed to cause water to flow from one tank to another in the direction opposite of the 

work flow. Countercurrent cascade rinsing is widely used to reduce the discharge rate of 

rinse water. Fresh water flows into the rinse tank located farthest from the process tank 

and overflows, in turn, to the rinse tanks closer to the process tank. This technique is 

termed countercurrent rinsing, because the part and the rinse water move in opposite 

directions. Over time, the first rinse becomes contaminated with drag-out and reaches a 

stable concentration that is lower than the process solution. The second rinse stabilizes at a 

lower concentration, which enables less rinse water to be used than if only one rinse tank 

were in place. The more countercurrent cascade rinse tanks (three-stage, four-stage, etc.), 

the less water is needed to adequately remove the process solution. 

Drag-in/Drag-out 

Rinsing 

A drag-in/drag-out rinse system may be a single tank or two tanks plumbed together. Parts 

enter the rinse system before and after processing in the bath. As parts enter the process 

bath, they drag in process chemicals present in the drag-in/drag-out rinse rather than plain 

rinse water. This rinsing configuration is an effective recovery method for process baths 

that have low evaporation rates. 

D-4

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-2 (Continued) 

Practice or 

Technology Description 

Drag-out Tank Drag-out tanks are rinse tanks that are initially filled with water and remain stagnant. Parts 

are rinsed in drag-out tanks directly after exiting the process bath. Gradually, the 

concentration of process chemicals in the drag-out tank rises. In the most efficient 

configuration, a drag-out tank is used after a heated process tank that has a moderate to 

high evaporation rate. Part of the fluid in the drag-out tank is returned to the process tank 

to replace the evaporative loss. The level of fluid in the drag-out tank is maintained by 

adding fresh water. 

Drip Shields Drip shields are installed between process tanks and rinse tanks to recover process fluid 

dripping off racks and barrels that would otherwise fall into rinse tanks or onto the floor. 

Often, drip shields are an inclined piece of polypropylene or other material that is inert to 

the process. 

Drip Tanks Drip tanks are similar to drag-out tanks except they are not filled with water. Parts exiting 

a process bath are held over the drip tank and the process fluid that drips from the parts is 

collected in the tank. When enough fluid is collected in the drip tank, it is returned to the 

process tank. Drip tanks are generally considered to be a less effective drag-out recovery 

practice than using drag-out tanks. 

Electrodialysis Electrodialysis is a membrane technology used to remove impurities from and recover 

process solutions. With this technology, a direct current is applied across a series of 

alternating anion and cation exchange membranes to remove dissolved metal salts and 

other ionic constituents from solutions. 

An electrodialysis unit consists of a rectifier and a membrane stack. The stack consists of 

alternating anion- and cation-specific membranes that form compartments. As the feed 

stream enters the unit, each alternating membrane compartment becomes filled with either 

dilute or concentrate. When the compartments are filled, a direct current is applied across 

the membrane. Cations in a dilute compartment traverse one cation-specific membrane in 

the direction of the cathode, and are trapped in that compartment by the next membrane, 

which is anion-specific. Anions from the neighboring dilute compartment traverse the 

anion-specific membrane in the direction of the anode, joining the cations, and are likewise 

trapped in the concentrate compartment by the next cation-specific membrane. In this way, 

the feed stream is depleted of ions, and anions and cations are trapped in each concentrate 

compartment. 

The feed stream is often from the first rinse tank in a countercurrent series, with a 

concentration of 5 gallons per liter (g/L) or more of total dissolved solids (TDS). The 

concentrate, with a TDS concentration of 50 g/L or more and a volume of less than 10% of 

the feed stream, is returned to the process. The dilute, representing more than 90% of the 

feed stream at a TDS concentration of typically 1 g/L or less, is recycled as rinse water or 

discharged to treatment. 

D-5

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-2 (Continued) 

Practice or 

Technology Description 

Electrolytic 

Recovery 

(Electrowinning) 

Electrolytic recovery is an electrochemical process used to recover metals from many types 

of process solutions, such as electroplating rinse waters and baths. Electrolytic recovery 

removes metal ions from a wastestream by processing the stream in an electrolytic cell, 

which consists of a closely spaced anode and cathode. Commercial equipment consists of 

several cells, a transfer pump, and a rectifier. Current is applied across the cell and metal 

cations are deposited on the cathodes. The wastestream is usually recirculated through the 

cell from a separate tank, such as a drag-out recovery rinse. 

Electrolytic recovery is typically applied to solutions containing nickel, copper, precious 

metals, and cadmium. Chromium and aluminum are poor candidates for electrolytic 

recovery. Drag-out recovery rinses and ion-exchange regenerant are common solutions 

that are processed using electrolytic recovery. Some solutions require pH adjustment prior 

to electrolytic recovery. Acidic, metal-rich, cation regenerant is an excellent candidate 

stream for electrolytic recovery, and is often electrolytically recovered without adjustment. 

In some cases, when the target concentration is reached, the wastestream is reused as cation 

regenerant. 

Evaporation Evaporation is a common chemical recovery technology. There are two basic types of 

evaporators: atmospheric and vacuum. Atmospheric evaporators, the more prevalent type, 

are relatively inexpensive to purchase and easy to operate. Vacuum evaporators are 

mechanically more sophisticated and are more energy-efficient. Vacuum evaporators are 

typically used when evaporation rates greater than 50 to 70 gallons/hour are required. 

Additionally, with vacuum evaporators, evaporated water can be recovered as a condensate 

and reused on site. 

A disadvantage of evaporation-based recovery is that all drag-out, including unwanted 

components, are returned and accumulate in the process bath. For this reason, deionized 

water is preferred as rinse water to prevent the introduction of water contaminants in the 

process bath. 

Flow Restrictor Flow restrictors prevent the flow in a pipe from exceeding a predetermined volume. They 

are commonly installed on a rinse tank’s water inlet. These devices contain an elastomer 

washer that flexes under pressure to maintain a constant water flow regardless of pressure. 

Flow restrictors can maintain a wide range of flow rates, from less than 0.1 gal/min to more 

than 10 gal/min. 

As a stand-alone device, a flow restrictor provides a constant water flow. As such, for 

intermittent rinsing operations, a flow restrictor does not coordinate the rinse flow with 

drag-out introduction. Precise control with intermittent operations typically requires a 

combination of flow restrictors and rinse timers. However, for continuous rinsing (e.g., 

continuous electroplating machines), flow restrictors may be adequate for good water 

control. 

Fog or Spray Rinse 

Over Tank 

Fog or spray rinsing is performed over a process bath to recover drag-out. Draining over a 

process bath can be greatly enhanced by spray or fog rinsing, which dilutes and lowers the 

viscosity of the film of process fluid clinging to the parts. This method of drag-out 

recovery is only possible if the evaporation rate of the process fluid is moderate to high. 

D-6

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-2 (Continued) 

Practice or 

Technology Description 

Good Tank Design Rinse tanks should be designed to remove the drag-out layer from the part and cause it to 

rapidly and thoroughly mix with the rinse water. Common elements of good tank design 

are positioning the inlet and outlet at opposite ends of the tank, using air or other agitation, 

using a flow distributor, and using the minimum size tank possible. 

Ion Exchange Ion exchange is a reversible chemical reaction that exchanges ions in a feed stream for ions 

of like charge on the surface of an ion-exchange resin. Resins are broadly divided into 

cationic or anionic types. Typical cation resins exchange H+

 for other cations, while anion 

resins exchange OH -

for other anions. 

In practice, a feed stream is passed through a vessel, referred to as a column, which holds 

the resin. The feed stream is typically dilute rinse water. The exchange process proceeds 

until the capacity of the resin is reached (i.e., an exchange has occurred at all the resin 

facilities). A regenerant solution is then passed through the column. For cation resins, the 

regenerant is an acid, and the H+

 ions replace the cations captured from the feed stream. 

For anion resins, the regenerant is a base, and OH -

ions replace the anions captured from 

the feed stream. The concentration of feed stream ions is much higher in the regenerant 

than in the feed stream; therefore, the ion-exchange process accomplishes both separation 

and concentration. 

Ion exchange is used for water recycling and/or metal recovery. For water recycling, 

cation and anion columns are placed in series. The feed stream is deionized and the 

product water is reused for rinsing. Often, closed-loop rinsing is achieved. The regenerant 

from the cation column typically contains the metal species, which can be recovered in 

elemental form via recovery. The anion regenerant is typically discharged to wastewater 

treatment. When metal recovery is the only objective, a single or double cation column 

unit containing selective resin is used. These resins attract divalent cations while allowing 

monovalent cations to pass, a process usually referred to as metal scavenging. Water 

cannot be recycled because contaminants other than the target cations remain in the stream 

exiting the column. 

Long Drip Time Long drip times over the process tank reduce the volume of drag-out reaching the rinsing 

system. Automatic lines can be easily programmed to include optimum drip times. On 

manual lines, racks are commonly hung on bars over process baths and allowed to drip. 

Barrels can be rotated over the process bath to enhance drainage. Some surfaces cannot 

tolerate long exposure to air due to oxidation or staining, and would therefore be unsuitable 

for extended drip times. 

Raising Bath 

Temperature 

Bath temperature and viscosity are inversely related. Operating at the highest possible bath 

temperature lowers viscosity and reduces drag-out. Higher bath temperatures also increase 

evaporation, which facilitates efficient recovery rinsing. 

Lowering Bath 

Concentration 

Operating at the lowest possible concentration reduces the mass of chemicals in a given 

volume of drag-out. Also, viscosity and concentration are directly related and lower 

process bath concentration lowers viscosity and reduces drag-out volume. Contaminants 

and other substances that build in concentration over the life of a process bath should be 

controlled at a low level, if possible. 

Part Position on 

Rack 

Positioning parts on racks to promote rapid draining includes minimizing the profile of the 

parts emerging from the bath, tilting and inverting cup-shaped parts, and avoiding 

placement of parts directly atop one another. 

D-7

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-2 (Continued) 

Practice or 

Technology Description 

Slow Part 

Withdrawal 

The faster a part is removed from a process bath, the thicker the layer of fluid clinging to 

the part will be. A slower withdrawal rate reduces the thickness of the fluid layer and 

reduces drag-out. Generally, this method of drag-out reduction can only be practiced on 

automatic lines where the withdrawal velocity can be programmed. 

Reverse Osmosis Reverse osmosis is a membrane separation technology used for chemical recovery. The 

feed stream, usually relatively dilute rinse water or wastewater, is pumped to the surface of 

the reverse osmosis membrane at pressures of 400 to 1,000 psig. The membrane separates 

the feed stream into a reject stream and a permeate. The reject stream, containing most of 

the dissolved solids in the feed stream, is deflected from the membrane while the permeate 

passes through. Reverse osmosis membranes reject more than 99% of multivalent ions and 

90% to 96% of monovalent ions, in addition to organic pollutants and nonionic dissolved 

solids. The permeate stream is usually of sufficient quality to be recycled as rinse water, 

despite the small percentage of monovalent ions (commonly potassium, sodium and 

chloride) that pass through the membrane. 

A sufficiently concentrated reject stream can be returned directly to the process bath. The 

reject stream concentration can be increased by recycling the stream through the unit more 

than once or by increasing the feed pressure. In multiple-stage units containing more than 

one membrane chamber, the reject stream from the first chamber is routed to the second, 

and so on. The combined reject streams from multistage units may, in some cases, have 

high enough concentrations to be returned directly to the bath. 

Timer Rinse 

Controller 

Rinse timers are electronic devices that control a solenoid valve. The timer usually 

consists of a button that, when pressed, opens the valve for a predetermined length of time, 

usually from 1 to 99 minutes. When the valve is open, make-up water is allowed to flow 

into a given tank. After the time period has expired, the valve is automatically shut. The 

timer may be activated either manually by the operator or automatically by the action of 

racks or hoists. 

Most rinse systems that are used intermittently benefit from the installation of a rinse timer, 

as operator error is eliminated. Rinse timers installed in conjunction with flow restrictors 

can provide precise control when the incoming water pressure may rise and fall. Rinse 

timers are less effective in continuous or nearly continuous rinse operations (e.g., 

continuous electroplating machines). 

Wetting Agents Wetting agents or surfactants may be added to some process baths to reduce viscosity and 

surface tension, thereby significantly reducing drag-out. 

Source: MP&M Site Visits, MP&M Surveys, Technical Literature. 

D-8

Appendix D - Pollution Prevention and Water Conservation Practices 

D.1.1 Drag-Out Reduction and Drag-Out Recovery 

The quantity of water needed for good rinsing for a given system is proportional 

to the quantity of drag-out from a process bath. Facilities can implement various methods that 

minimize the rate of drag-out (measured as gallons per square foot of part surface area) and/or 

they can implement direct drag-out recovery. The drag-out rate for an individual process 

operation (e.g., cleaning or plating) depends on numerous factors, including process type, shape 

of parts processed, production equipment, and processing procedures, which include human 

factors. Of these factors, the shape of the parts and the type of device used to move the parts 

(e.g., racks, baskets, barrels) usually have the greatest influence on drag-out rates. Tables D-3 

and D-4 present drag-out rate estimates from two sources in the literature for various shaped 

parts. 

Table D-3 

Average Drag-Out Losses - from Soderberg’s Work 

Nature of Work Drainage Drag-Out Rate (gal/1,000 ft2) 

Vertical 

Well drained 0.4 

Poorly drained 2 

Very poorly drained 4 

Horizontal 

Well drained 0.8 

Very poorly drained 10 

Cup Shapes 

Well drained 8 

Very poorly drained 24 

Source: Reference 4. 

D-9

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-4


Average Drag-Out Losses - from Hogaboom’s Work


Electroplating Solution Type 

Drag-Out Rate (gal/1,000 ft2) 

Flat Surfaces Contoured Surfaces 

Brass 0.95 3.3 

Cadmium 1 3.1 

Chromium (33 oz/gal) 1.18 3 

Chromium (53 oz/gal)

a 4.53 11.9 

Copper cyanide 0.91 3.2 

Watts nickel 1 3.8 

Silver 1.2 3.2 

Stannate tin 0.83 1.6 

Acid zinc 1.3 3.5 

Cyanide zinc 1.2 3.8 

Source: Reference 4.
 a

Increased viscosity, caused by an increase in concentration, can increase the drag-out volume approximately three


times with less than double the concentration increase.


Several factors other than shape, some of which are interrelated, influence the 

drag-out rate for a given process and part. Table D-5 lists these and other key factors and 

describes their impact on drag-out rates. Also listed are examples of water conservation practices 

that reduce the generation of drag-out, and the major restrictions that are associated with these 

practices. Table D-6 shows the effect of altering the withdrawal rate and drain time. 

Soderberg’s data indicate that the shape of the part has a significant influence on 

drag-out rate. Cup-shaped parts, including intricately designed parts with internal surfaces, can 

generate five or more times the drag-out than flat surfaced parts with the same surface area. 

Hogaboom’s data show a similar trend for flat versus contoured surfaces. These data also show 

that the type and concentration of the electroplating solution influence the drag-out rate. For 

example, some solutions, such as stannate tin, drain effectively, while others, such as 

concentrated chromium electroplating solutions (53 ounces per gallon (oz/gal) drain poorly. As 

to the type of device used to move parts, barrels (used to hold fasteners or other small parts that 

cannot be practically held by racks) generate more drag-out than racks, because of the surface 

area of the barrel and its tendency to hold the solution. 

D-10

Appendix D - Pollution Prevention a

Table D-5 

Factors Affecting Drag-Out 

D-11


Factor Affecting 

Drag-Out Impact on Drag-out 

Potential Pollution Prevention and Water 

Conservation Practices Re

Bath Concentration Concentration and drag-out are 

directly related. 

Operate at lowest concentration possible. Remove all contaminants promptly. 

Concentration rang

Bath Temperature Higher temperatures lower drag-out 

by lowering viscosity. 

Operate at highest possible temperature. Temperature range 

Bath Viscosity High viscosity raises drag-out by 

increasing the thickness of the fluid 

layer clinging to the part. 

Operate at highest temperature and lowest 

concentration possible. Add wetting agent. 

Concentration and 

limited by process

compatible. 

Part Configuration Cup shapes result in 8-20 times the 

drag-out volume of flat shapes. 

Drain holes can be added to many cup-shaped 

parts to improve drainage of drag-out. 

Functionality of pa

drain holes or othe

configuration. 

Part Orientation Orientation on rack can be 

optimized to minimized drag-out. 

Keep records of optimal orientations. Train 

operators. 

None. 

Withdrawal Rate Doubling speed of withdrawal 

results in a fourfold increase in drag-out volume. 

Program automatic equipment for slow 

withdrawal. 

Impossible to cons

automation. 

Drain Time Long drain times and barrel 

rotations greatly reduce drag-out. 

Program automatic equipment for long drain times. Impossible or diffi

practice without au

limited by staining 

coatings. 

Rack versus Barrel Barrels produce greater drag-out 

than racks. 

(See “Rack/Barrel Design) Part transport devi

size. 

Rack/Barrel Design Drag-out volume is related to barrel 

design. 

Redesign barrels with largest holes possible. Barrel design limit

configurations. 

Rack/Barrel Condition 

Loose rack coating cause reservoirs of fluid to be transported with rack. 

Maintain a schedule of maintenance and recoating. None. 

Operator Awareness Poor operator awareness greatly 

increases drag-out or offsets other 

practices. 

Require training programs for operators. None. 

Source: MP&M Site Visits, MP&M Surveys, Technical Literature. 
Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-6


Effect of Withdrawal Rate and Drain Time on Drag-out Ratea


Micro-Etch Results 

Withdrawal 

Rate (ft/min) 

Time of 

Withdrawal 

(seconds) 

Drain Time 

(seconds) 

Total 

Time 

(seconds) 

Drag-out 

(gal/1,000 ft2

) 

Baseline 100 1.7 3.4 5.1 3.13 

Slower rate of withdrawal 11 14.9 2.5 17.4 1.73 

Intermediate withdrawal 

rate and longer drain time 

40 4.3 12.1 16.4 1.83 

Electroless Copper 

Results 

Withdrawal 

Rate 

(ft/min) 

Time of 

Withdrawal 

(seconds) 

Drain 

Time 

(seconds) 

Total 

Time 

(seconds) 

Drag-out 

(gal/1,000 ft2

) 

Baseline 94 1.8 5.2 7 1.55 

Slower Rate of Withdrawal 12 13.9 3.2 17 0.78 

Intermediate Withdrawal 

Rate and Longer Drain 

Time 

40 4.3 11.9 16.3 0.75 

Source: Reference 4.
 a

The effects of changing the withdrawal rate and drain time were measured at a printed circuit board manufacturing


facility. 


The following is a list of drag-out reduction practices that facilities can implement 

on electroplating or surface finishing lines: 

� Lower process solution viscosity and/or surface tension by decreasing 

chemical concentration, increasing bath temperature, or using wetting 

agents; 

� Reduce drag-out volume by modifying rack/barrel design and perform rack 

maintenance to avoid solution trapping; 

� Position parts on racks in a manner that avoids trapping solution; 

� Reduce speed of rack/barrel withdrawal from process solution an/or 

increase dwell time over process tank; 

� Rotate barrels over the process tank to improve drainage; 

� Use spray/fog rinsing over the process tank (limited applicability); 

� Use drip boards and return process solution to the process tank; 

D-12

Appendix D - Pollution Prevention and Water Conservation Practices 

� Use drag-out tanks, where applicable, and return solution to the process 

tank; and 

� Work with customers to ensure that part design maximizes drainage. 

D.1.2 Improved Rinse Tank Design and Rinsing Configurations 

Rinse tank design and rinsing configuration greatly influence water usage. The 

key objectives for optimal rinse tank design are to quickly remove drag-out from the part and 

completely disperse the drag-out throughout the rinse tank. Achieving these objectives reduces 

the time necessary for rinsing and minimizes the concentration of contaminants on the part when 

it leaves the rinse tank. Examples of good design include locating water inlet and discharge 

points of the tank at opposite positions in the tank to avoid short-circuiting, and using air 

agitation for better mixing (5). 

Various rinsing configurations are used by MP&M facilities. Having single-rinse 

tanks following each process tank is the most inefficient use of rinse water. Multiple-rinse tanks 

connected in series (i.e., countercurrent cascade rinsing) reduces the water needs of a given 

rinsing operation by one or more orders of magnitude. Spray rinsing can also reduce water use 

requirements, but the achievable percent reduction is usually less than for countercurrent cascade 

rinsing. Other configurations that reduce water use include cascade, reactive, and dual purpose 

rinses. 

D.1.3 Rinse Water Use Control Devices 

Regardless of the type of rinsing configuration used, facilities can reduce their 

water use by coordinating water use and water use requirements. Matching water use to water 

use requirements can optimize the quantity of rinse water used for a given work load and tank 

arrangement (5). Not controlling water use negates the benefits of using multiple rinse tanks or 

other water conservation practices and increases water usage. 

Facilities may wish to implement at least one effective method of water use 

control on all electroplating or surface finishing lines. Effective water use controls include, but 

are not limited to: 

� Use of softened or deionized water for rinsing. 

� Flow restrictors (flow restrictors as a stand-alone method of rinse water 

control are only effective with plating lines that have constant production 

rates, such as automatic plating machines. For other operations, there 

must also be a mechanism or procedure for stopping water flow during 

idle periods.). 

� Conductivity controls. 

D-13

Appendix D - Pollution Prevention and Water Conservation Practices 

� Timer rinse controls. 

� Production-activated controls (e.g., spray systems activated when a rack or 

barrel enters/exits a rinse station). 

D.1.4 Metal Recovery and Rinse Water Reuse Technologies 

MP&M facilities use various technologies to recover metals drag-out and rinses 

and reuse the rinse water. The technologies most commonly used are evaporation, ion exchange, 

electrolytic recovery (also referred to as electrowinning), reverse osmosis, and electrodialysis. 

Table D-7 presents examples of metal recovery technologies and the drag-out/rinses to which 

they are primarily applied. 

Table D-7 

Examples of Metal Recovery Methods 

Chemistry or Process 

with Which Rinse is Associated Recovery Technology 

Brass electroplating Electrolytic recovery, evaporation 

Cadmium (cyanide) electroplating Electrodialysis, electrolytic recovery, evaporation, ion 

exchange, reverse osmosis 

Cadmium (noncyanide) electroplating Electrodialysis, electrolytic recovery, evaporation, ion 

exchange, reverse osmosis 

Chromate conversion coating of aluminum Evaporation 

Chromium (hard) anodizing Evaporation, mist eliminator 

Chromium electroplating - decorative (Cr+6) Evaporation 

Chromium electroplating - decorative (Cr+3) Evaporation 

Copper (cyanide and sulfate) electroplating Electrolytic recovery, evaporation, ion exchange, reverse 

osmosis 

Gold electroplating Electrolytic recovery, ion exchange 

Lead-tin electroplating Evaporation, ion exchange 

Nickel electroplating Electrodialysis, electrolytic recovery, evaporation, ion 

exchange, reverse osmosis 

Nickel electroless plating Evaporation, ion exchange 

Nickel sealant Reverse osmosis 

Silver electroplating Electrolytic recovery, evaporation, ion exchange 

Zinc (cyanide) electroplating Electrolytic recovery, evaporation, reverse osmosis 

Zinc (noncyanide) electroplating Electrolytic recovery, evaporation, ion exchange, reverse 

osmosis 

Zincate Evaporation 

Source: Reference 5. 

D-14 
Appendix D - Pollution Prevention and Water Conservation Practices

D-15

H and

Valve

Fresh W ater

W ork Flow

5 sec. w ithdraw rate

5 sec. dw ell tim e

P lating

Tank

R inse

Tank

Figure D-1(a). 

H and

Valve

Fre sh W ater

W ork Flow

1 5 sec. w ithd ra w rate

15 sec. dw ell tim e

P lating

Tank

R inse

Tank

F low

R estrictor

Figure D-1(b). Rinse Tank with Flow Reduction

D.1.5 Summary of Water Conservation Methods

Figures D-1(a) through (f) present six examples of rinsing configurations with

increasingly good levels of water use practices. nse systems is described below. 

These configurations can be operated to provide adequate rinsing and are common at MP&M

facilities. ver, the quantity of water needed for the same rinse quality may vary by as much

as two orders of magnitude from the lowest level to the best level of water use.

Single Rinse Tank

Single

Each of these ri

Howe
Appendix D - Pollution Prevention and Water Conservation Practices

D-16

F resh Water

W ork Flow

15 sec. w ithdraw rate

15 sec. dw ell tim e

P lating

Tank

R inse

Tank

H and

Valve

F resh Water

R inse

Tank

F low

R estrictor

Figure D-1(c). e Tanks with Flow Reduction

W ork Flow 15 sec. w ithdraw rate

15 sec. dw ell tim e

P lating

Tank

R inse

Tank

F re sh W ater

R inse

Tank

C onductivity

C ontroller

D rag-O ut

Tank

R ecovered R inse

Figure D-1(e). ltiple Rinse Tanks with Flow Reduction and Drag-Out Recovery

W ork Flow

15 sec. w ithdraw rate

15 sec. dw ell tim e

P lating

Tank

R inse

Tank

H and

Valve

F resh Water

R inse

Tank

F low

R estrictor

Figure D-1(d). ntercurrent Rinsing with Flow Reduction

Multiple Rins

Mu

Cou
Appendix D - Pollution Prevention and Water Conservation Practices 

15 s e c . w ithdraw ra te W ork Flow

15 s e c . dw ell tim e 

P la tin g 

Tank 

R e cycle 

R in s e 

Tank 

D rag -O ut 

Tank 

R e c o v e red R ins e 

Cation Colmn 

Anion column To tre a tm e n t 

E lectro w inning 

Un it 

M e ta l d epleted 

elec troly te reus e d 

fo r re g eneratio n 

R egen erants 

Scrap m etal 

to recycle 

Figure D-1(f). Multiple Rinse Tanks with Water Recycle, 

Drag-Out Recovery, and Metal Recovery 

Figure D-1(a) is an example of inefficient water use. This configuration uses a 

single-rinse tank with either continuous water flow or manual use control. To coordinate rinse 

water needs and use, the operator manually turns on the water valve to give the correct flow rate 

and then turns it off when the flow is no longer needed. The flow-rate setting will usually vary 

by operator and the water valve may be left open during idle production periods. The single rinse 

tank configuration uses rinse water at a very high rate, even if water use is coordinated with the 

introduction of drag-out. In the example shown, with a 1-gallon-per-hour (gph) drag-out rate, the 

rinse water requirement is 30 gallons per minute (gpm), based on rinsing of Watts nickel plating 

solution and a rinsing criterion of 50 milligrams per liter (mg/L) nickel. If water use and dragout introduction are not coordinated, an even higher rinse water use rate would be needed to meet 

a given rinse criterion. 

Figure D-1(b) shows a rinsing configuration where simple rinse water reduction 

methods have been implemented. The water use is still inefficient because a single rinse tank is 

used versus multiple rinse tanks. However, with this configuration, the drag-out rate is reduced 

by controlling the withdrawal rate of the part (increasing the withdrawal rate from 5 to 15 

seconds) and by holding the part over the process tank (increasing dwell time from 5 to 15 

D-17 
Appendix D - Pollution Prevention and Water Conservation Practices 

seconds) to permit the drag-out to drip into the tank. The rinse water flow rate is controlled at a 

constant flow by a flow restrictor. The flow restrictor is usually sized to provide adequate rinsing 

at all times, and is more acceptable for constant production rates, such as those often found with 

automated plating machines. However, this configuration is inefficient when the work is 

intermittent because the rinse water flow rate must be set high enough to provide adequate 

rinsing during peak production periods. In addition, a large quantity of rinse water is wasted 

during low or idle production periods, unless the water flow is manually stopped. 

Figure D-1(c) shows a rinsing configuration using multiple rinse tanks, which 

provides a moderately efficient use of water. This configuration is referred to as parallel rinsing, 

where each of the two rinse tanks are fed with fresh water and they each discharge to treatment. 

This arrangement can reduce water use to less than 50 percent of that used in Figure D-1(a). 

Figure D-1(d) shows a more efficient rinsing configuration. This configuration is 

similar to that shown in Figure D-1(c), except that wastewater from the second rinse tank flows 

back into the first rinse tank to provide more efficient rinsing with less water use. Wastewater 

from the first rinse tank is then discharged to treatment. In this configuration, known as 

countercurrent cascade rinsing, the rinse water flows in a direction opposite to the part flow. 

This arrangement can reduce water use by more than 90 percent over the rinse configuration in 

Figure D-1(a). 

Figure D-1(e) shows a very efficient rinsing configuration. There are three key 

elements to this rinse system: drag-out reduction/recovery, countercurrent cascade rinsing, and 

water-use control. This configuration reduces/recovers drag-out by controlling the withdrawal 

rate and dwell time and by installing a drag-out recovery tank. This tank can reduce the drag-out 

entering the countercurrent cascade rinses by up to 90 percent, depending on the surface 

evaporation rate of the process tank. A conductivity controller controls the feed to the 

countercurrent cascade rinses. This type of device coordinates water use with drag-out 

introduction and reduces the influence of human error found with manually controlled rinses. An 

alternative device is a timer rinse control, which is as effective as a conductivity controller when 

there is no variability in drag-out volume between rinsing events. 

Figure D-1(f) shows a rinse system that uses an ion exchange/electrolytic recovery 

unit as a chemical recovery and water recycling technology. This rinsing configuration can 

reduce water use by more than 99 percent compared to the rinse configuration in Figure D-1(a), 

since wastewater is discharged only from the regeneration cycle of the ion-exchange unit. 

Table D-1 presents examples of additional practices and technologies that could 

be components of a well-designed rinse system. 

D.1.6 Influences on Flow Rates 

Available data show that rinse water use rates are related to production when 

measured in terms of the surface area of parts processed. Other factors that influence rinse water 

D-18

Appendix D - Pollution Prevention and Water Conservation Practices 

use rates include the drag-out rate (gallons per 1,000 square feet of workload), the rinse water 

purity criteria (mg/L metal), the concentration of TDS in the bath (mg/L TDS), rinse tank design 

and configuration (e.g., single overflow rinse versus countercurrent cascade rinse), and the type 

of rinse water flow control (e.g., manual versus conductivity controlled). Section D.1.5 discusses 

drag-out rinse tank design and configuration and rinse water flow control. The other factors are 

discussed below. 

D.1.6.1 Rinse Water Purity Criteria 

Rinse water purity criteria are the levels of tolerable contamination in the rinse 

water. These levels vary for different processes and types of products. For example, rinse water 

used after cleaning typically does not have to be as pure as rinse water used following plating, 

since rinse water that remains on the plated part (essentially the drag-out from the rinse tank) will 

leave spots after it evaporates if the concentration of dissolved solids in the rinse water is too 

high. Although preliminary and intermediate processing steps such as cleaning and etching 

usually do not require as pure a rinse water as final rinsing, the rinse water needs to be pure 

enough to stop chemical reactions (e.g., etching) and prevent the contamination of subsequent 

process solutions. Among plating processes, differences also exist in rinse water quality 

requirements. Parts plated for engineering or functional purposes (e.g., corrosion resistance) can 

often be rinsed in water that is significantly less pure than decoratively plated parts rinses. 

High-purity water is needed for various rinsing operations. In some cases (e.g., 

electronics parts rinsing), tap water is not pure enough to serve as rinse water. Before use as 

rinse water for this type of operation, the source water is purified by reverse osmosis and/or ion 

exchange to remove dissolved solids and other constituents. Source water is sometimes treated 

even for common rinsing operations, especially when the water supply is high in dissolved solids. 

The metal finishing industry has had rinse water quality requirements for decades. 

They are typically expressed in mg/L of TDS or in conductivity or resistivity units (resistivity is 

the inverse of conductivity). Table D-8 summarizes some generalized rinse criteria found in the 

literature (4). 

D-19

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-8


Generalized Rinse Criteria


Type of Rinse 

Normal Range for Adequate Rinsing 

(mg/L TDS) 

Alkaline Treatment/Acid Treatment Rinse 400 to 1,000 

Functional or Engineering Plating Rinse 100 to 700 

Decorative or Bright Plating Rinse 5 to 40 

Source: Reference 4. 

D.1.6.2 Bath Concentration 

The concentration of a bath (which can be expressed in g/L TDS) will affect the 

quantity of water needed for good rinsing. Baths that are more concentrated (i.e., higher TDS) 

will require more rinse water to meet the same rinse water purity criteria as a less concentrated 

bath. The bath concentration depends on the type of bath. For example, a typical acid zinc 

electroplating bath will have a TDS concentration of 166 g/L and a typical copper cyanide 

electroplating bath will have a TDS concentration of 250 g/L (6,7). For equal volumes of dragout from these two baths, the copper cyanide rinse flow must be 1.5 times greater to achieve the 

same rinse quality criteria (i.e., 250/166 = 1.5). This calculation does not account for the 

differences in viscosity that will also affect the volume of drag-out. For example, for flat 

surfaces, the drag-out rate for a 396-g/L chromic acid bath is 3.8 times greater than that of a 247-

g/L bath (6,7). In some cases, the TDS concentration of the bath inadvertently increases due to a 

buildup of bath contaminants (e.g., iron may accumulate in a chromic acid bath due to the attack 

of the base metal). The TDS added by the contaminants may affect the drag-out rate in the same 

manner as its intended bath constituents (e.g., chromic acid). Therefore, operating a bath at the 

lowest concentration necessary to perform the job properly and maintaining bath contaminants at 

low levels is a significant pollution prevention measure. 

D.1.7 Technical Literature 

Table D-9 presents, for several types of rinses, calculated flow rates for a singlestage overflow rinsing configuration and a two-stage countercurrent cascade rinsing 

configuration. Both rinsing configurations are assumed to have flow control (i.e., water use is 

coordinated with drag-out introduction using a conductivity control or other device). This table 

presents the TDS concentration in the associated bath (from literature), the target TDS in the 

rinse (based on the rinsing criteria), the part type, the assumed drag-out rate, and two production 

normalized flow (PNF) values. 

The first value, PNF 100% Control, is a calculated value based on the assumption 

that a facility perfectly coordinates work flow and rinse water use (e.g., using a conductivity 

controller). In actual operations, perfect coordination is nearly impossible to achieve because the 

quantity of rinse 

D-20

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-9


Rinse Water Required for Various Plating Processes Based on Literature Va

D-21


Process Rinse Configuration TDS Concentrationa 

Target TDS 

Concentration in 

Rinsea Part Type Drag-out Ratea 

PNF 100% C

(gal/ft2

Acid Zinc Single overflow 166 g/L Functional: 100-700 

mg/L (used 400 mg/L) 

Flat 1.3 gal/1,000 ft2 0.54 Contoured 3.5 gal/1,000 ft2 1.5 

2-stage countercurrent 

cascade 

166 g/L Functional: 100-700 

mg/L (used 400 mg/L) 

Flat 1.3 gal/1,000 ft2 0.024 Contoured 3.5 gal/1,000 ft2 0.072 

Silver Cyanide Single overflow 370 g/L Bright: 5-40 mg/L (used 

20 mg/L) 

Flat 1.2 gal/1,000 ft2 22 Contoured 3.2 gal/1,000 ft2 58 

2-stage countercurrent 

cascade 

370 g/L Bright: 5-40 mg/L (used 

20 mg/L) 

Flat 1.2 gal/1,000 ft2 0.16 Contoured 3.2 gal/1,000 ft2 0.43 

Copper Cyanide Single overflow 250 g/L Functional: 100-700 

mg/L (used 400 mg/L) 

Flat 0.91 gal/1,000 ft2 0.57 Contoured 3.2 gal/1,000 ft2 2 

2-stage countercurrent 

cascade 

250 g/L Functional: 100-700 

mg/L (used 400 mg/L) 

Flat 0.91 gal/1,000 ft2 0.023 Contoured 3.2 gal/1,000 ft2 0.081 

Acid Descale Single Overflow 248 g/L Clean: 400-1000 mg/L 

(used 700 mg/L) 

Flat 1 gal/1,000 ft2 (estimated) 3.5 Contoured 3 gal/1,000 ft2 (estimated) 11 

2-stage countercurrent 

cascade 

248 g/L Clean: 400-1000 mg/L 

(used 700 mg/L) 

Flat 1 gal/1,000 ft2 (estimated) 0.019 Contoured 3 gal/1,000 ft2 (estimated) 0.056 

Alkaline Clean (Proprietary Chemistry) 

Single overflow 90 g/L Clean: 400-1000 mg/L 

(used 700 mg/L) 

Flat 1 gal/1,000 ft2 (estimated) 0.13 Contoured 3 gal/1,000 ft2 (estimated) 0.39 

2-stage countercurrent 

cascade 

90 g/L Clean: 400-1000 mg/L 

(used 700 mg/L) 

Flat 1 gal/1,000 ft2 (estimated) 0.011 Contoured 3 gal/1,000 ft2 (estimated) 0.033 

Sources: References 4, 6, and 7. 

aTDS concentrations are from References 6 and 7, based on bath formulations. Target TDS concentrations are based on criteria presented in Section 3.2.1 (Reference 4

References 4 and 5 unless data were not available, in which case rates were assumed based on technical knowledge of the operations. 
Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-9 (Continued) 

1. Acid zinc formulation: 

ZnSO4(7H2O) 240 g/L 

NH4Cl 15 g/L 

Al2(SO4)3(18H2O) 30 g/L 

Licorice 1 g/L 

2.	 Equation used to calculate rinse flow and flow per square foot for single overflow rinse: 

Solving for Q: 

Where: 

D = Drag-out per ft2 (gal)


Ce = Target concentration of rinse (oz/gal)


Co = Concentration of process bath (oz/gal)


Cr = Target concentration of final rinse (oz/gal)


M = Interval between drag-out events (minutes)


Q = Flow (gal/min)


Note: Any interval M can be chosen. Q, when divided by the work rate, ft

2

/M, yields the gal/ft

2

 in the table and the gal/ft

2 number


remains the same for any M.


3. Equation used to calculate 100 percent controlled flow and gallons per square foot for countercurrent cascade rinse: 

xWhere n = number of rinse stages 

For 50 percent controlled flow, Q was multiplied by a factor of 2. 

With 100 percent controlled flow, the introduction of drag-out and rinse water into the rinse tank are perfectly coordinated and, 

therefore, the rinse water required to meet the target concentration of the final rinse is equal to Q. With 100 percent excess flow, the 

introduction of drag-out and rinse water are not perfectly coordinated and an excess of 100 percent of Q (or 2Q) is used to meet the 

target concentration of the final rinse. 

4. Silver cyanide formulation (middle of high-speed bath range): 

AgCN 97.5 g/L 

KCN 152.5 g/L 

K2CO3 52.5 g/L 

KNO3 50 g/L 

KOH 17 g/L 

5. High-efficiency copper cyanide formulation: 

CuCN 75 g/L 

KCN 133 g/L 

KOH 42 g/L 

6. Acid descale formulation: 

20% H2NO3 (by volume) 

1.5% HF (by volume) 

All bath formulations and equations are from References 4, 6, and 7. 

D-22

Appendix D - Pollution Prevention and Water Conservation Practices 

water needed to meet a given rinse criterion usually cannot be added exactly at the time that dragout enters and is dispersed in the rinse tank. For example, when a barrel of parts is rinsed, it is 

usually placed in a rinse tank for 1 to 3 minutes. The rinse water volume needed to meet the 

rinse criterion may be 50 gallons or more. The flow rate of water into the rinse tank is typically 

less than 10 gpm (flow rates into rinse tanks vary depending on the pipe size and water pressure 

and may be reduced by a flow restrictor). Therefore, it may take 5 minutes to add the 50 gallons 

of rinse water. Because of this, actual water use rates will be higher than those presented in the 

column, PNF 100% Control. A reasonable assumption is that good water flow control will result 

in a PNF twice that of the calculated values that assume 100 percent control. These flows are 

shown as PNF 100% Excess. 

Machining Operations 

Many machining operations use metal-working fluids to cool and lubricate parts 

and machining tools during cutting, drilling, milling, and other machining operations. These 

fluids become contaminated and begin to lose their working characteristics. If neglected, the 

fluids become unusable and require treatment and disposal. Through proper care, the life span of 

the fluids can be extended indefinitely. For most machining operations, prolonging metalworking fluid life reduces the cost of treatment and disposal, as well as the cost of fresh coolant. 

Many MP&M facilities use some type of pollution prevention and water 

conservation practices for machining wastewaters. Some facilities have implemented numerous 

pollution prevention and water conservation methods and technologies that result in very low 

machining wastewater discharge rates and in some cases eliminate the discharge of machining 

fluids. Pollution prevention and water conservation practices are applicable to all machining 

operations; however, process-related factors and site-specific conditions may restrict the utility of 

certain methods. 

D.2.1 Wastewater Generation from Machining Operations 

Various types of metal-working fluids, also termed cutting fluids and coolants, are 

used in machining operations to improve the life and function of machine tools. During 

machining, these fluids are circulated over working surfaces, reducing friction, cooling the tool 

and part, and removing metal chips from the work face. The type of fluid used depends on the 

type of machining being performed and the preference of the site. The fluids are broadly divided 

into four groups: straight oil (neat oils), synthetic oils, semisynthetic, and soluble oil. The most 

commonly used fluids are soluble oils, synthetics, and semisynthetics. 

Water-soluble coolants are prepared by mixing a concentrated coolant with water 

in a 1:15 to 1:30 ratio to produce a fluid with a 90- to 98-percent water content. Most watersoluble coolants are suitable for light- and medium-duty operations. Synthetic coolants are 

designed for high cooling capacity, lubricity, and corrosion prevention. Common chemical 

agents in synthetics include: amines and nitrites for rust prevention; nitrates for nitrite 

stabilization; phosphates and borates for water softening; soaps and wetting agents for 

D-23


D.2 
Appendix D - Pollution Prevention and Water Conservation Practices 

lubrication; phosphorus, chlorine, and sulfur compounds for chemical lubrication; glycols to act 

as blending agents; and biocides to control bacteria growth. Semisynthetics contain small 

dispersions of oil in an almost otherwise organic water-dilutable system. Straight oils are good 

lubricants, but are less effective for cooling, and therefore are limited mostly to use in low-speed 

operations (8). 

Metal-working fluids are periodically discarded because of reduced performance 

or development of a rancid odor. The fluids that contain a large percentage of oil typically are 

contract hauled as solid waste for disposal or recovery. Fluids with lower oil content typically 

are sent to a site’s wastewater treatment system for treatment and subsequent discharge. 

Metal-working fluids degrade mainly because of contamination with tramp oil and 

dirt and by bacterial growth, which can be accelerated by tramp oil contamination. Tramp oil 

contamination is caused mostly by oil from the part’s surface during machining and by leaks of 

lubricating and hydraulic oils from the machine. Airborne dust or poor housekeeping practices 

can cause dirt to accumulate. Bacteria are initially contributed from the surfaces of the machine 

and parts and from the air. More than 2,000 known species of bacteria have been reported to 

affect and eventually destroy the stability of machining fluids (9). Bacteria feed on the fluids’ 

chemicals, causing the fluids to lose lubricity and corrosion inhibition. Under anaerobic 

conditions, sometimes caused by floating tramp oil in coolant sumps, bacteria generate a 

hydrogen sulfide odor. 

In addition to spent fluid, machining operations may generate wastewater from 

rinsing. Machined parts may be rinsed to remove fluid, chips and other foreign materials. 

However, parts typically are not rinsed following machining. More frequently, the fluid is 

permitted to remain on the part to inhibit corrosion, is wiped off using shop towels, or is cleaned 

in an alkaline cleaning or degreasing operation. 

The quantity of wastewater generated by a machining operation depends primarily 

on the volume of work performed. Production volume can be roughly measured by the quantity 

of metal stock removed by turning, milling, boring, broaching, cutting and other machining 

operations. For most machining operations, the removed metal consists of small fragments 

called chips or fines. Most chips carry a thin film of fluid on their surfaces, which, when it 

drains, is another source of wastewater. 

D.2.2	 Pollution Prevention and Water Conservation Practices for Machining 

Operations 

The Agency has identified two categories of pollution prevention and water 

conservation practices and technologies that can be used to reduce metal-working fluid 

discharge: those used to prevent metal-working fluid contamination and those used to extend the 

life of machining fluids, including recovering and recycling metal-working fluids. Within each 

of these categories are several specific practices and technologies. Table D-10 presents several 

examples of these practices, which are discussed below. There may be other practices and 

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Appendix D - Pollution Prevention and Water Conservation Practices 

technologies not identified here that can reduce metal-working fluid discharge. Therefore, the 

list provided below is not exhaustive. 

Table D-10 

Potential Pollution Prevention and Water Conservation Methods 

Applicable to Machining Operations 

Pollution Prevention/Water 

Conservation Method Examples Applicability 

Prevention of Metal-Working Fluid Contamination 

Reduce contamination from tramp 

oil 

Use coolant in hydraulic and other 

oil systems. 

Applicable to most machines. In 

most cases, requires use of special 

fluid. 

Replace hydraulics with electrical 

systems. 

Limited applicability. Practical 

only during major equipment 

overhaul. 

Machine maintenance. Applicable to all machines. Should 

be performed at regularly scheduled 

intervals. 

Reduce contamination from makeup water Use deionized water for initial 

make-up of working fluid and to 

account for evaporative losses. 

Applicable to all machining 

operations using a water-soluble 

fluid. Especially important in areas 

where the water supply is high in 

TDS. 

Reduce contamination from sumps Sterilize sumps during clean-out 

using steam. 

Applicable to all machining 

operations. Especially important 

with large concrete sumps. 

Use metal inserts or coat walls of 

concrete sumps. 

Applicable to in-ground concrete 

sumps. 

Extension of Metal-Working Fluid Life 

Raw material substitution Use high quality fluids with needed 

“additive package.” 

Most machining operations can 

benefit from the use of high-quality 

fluids that can extend fluid life, 

while reducing bacterial growth, 

improving lubricity, reducing 

friction, and providing corrosion 

protection. 

Equipment modification Replace sump’s air agitation with 

mechanical agitation. 

Applicable to central sumps with air 

agitation. 

Install tramp oil removal device. Limited mainly to external sumps. 

Fluid Monitoring Measure pH, coolant concentration, 

tramp oil concentration, and 

bacterial count weekly or more 

frequently. 

Applicable to all machining 

operations. Larger operations can 

use data for statistical process 

control. 

D-25

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-10 (Continued) 

Pollution Prevention/Water 

Conservation Method Examples Applicability 

Extension of Metal-Working Fluid Life (continued) 

Metal-working fluid recycling Use methods and technologies for 

removing fluid contaminants (e.g., 

filtration, centrifuge, 

pasteurization). 

Simple filtration methods can be 

used by all machining operations. 

More sophisticated equipment is 

limited to larger operations. 

Recycle chip drainage. Applicable to all machining 

operations. Requires clean 

handling and storage methods to 

prevent contamination. 

Source: MP&M Site Visits, MP&M Surveys, Technical Literature. 

D.2.2.1 Prevention of Metal-Working Fluid Contamination 

Facilities can implement various methods to reduce the amount of fluid 

contamination. Several of these methods are discussed below. 

Reduction of Contamination From Tramp Oil. Tramp oil is a primary 

contaminant in machining fluids and for many facilities the major cause of metal-working fluid 

degradation. EPA has identified the following methods to reduce contamination of metalworking fluid with tramp oil. 

� Use of Coolant in Hydraulic and Other Oil Systems. Some metal-working 

coolants are formulated to be used as hydraulic fluid and/or lubricant in 

concentrated form and as a coolant in its dilute form (i.e., diluted with 

water). When used as a hydraulic fluid or lubricant, leaks of the fluid will 

assimilate into the coolant without causing contamination. 

� Replacement of Hydraulics with Electrical Systems. Hydraulic systems on 

some machines can be replaced by newer electrical systems that do not 

contain hydraulic fluid. This replacement could be economically 

performed during major equipment overhauls. 

� Machine Maintenance. Machine design and age may affect the quantity of 

hydraulic oil that leaks to the metal-working fluid during machining 

operations. There are numerous hydraulic systems used with machines, 

depending on the type of machine. These systems will leak variable 

quantities of oil depending on design, sealing mechanisms, operating 

pressures, and other factors. Older machines, especially those that are not 

properly maintained, can leak excessively from hydraulic seals. Facilities 

D-26

Appendix D - Pollution Prevention and Water Conservation Practices 

should implement scheduled maintenance of machines to check and repair 

sealing mechanisms. 

Reduction of Contamination from Make-Up Water. Make-up water contributes to 

the dissolved solids content of the metal-working fluid, reducing fluid life. This problem occurs 

more rapidly when water with high TDS is used for evaporative make-up. Certain dissolved 

solids or minerals cause more problems for metal-working fluids than others. For example, 

chloride salts and sulfates corrode at levels of greater than 100 parts per million. Sulfates also 

promote the growth of sulfate-reducing bacteria that cause fluids to become rancid. When 

minerals become concentrated in the fluid, they can cause increased corrosion, gumming, and 

machine wear (6). Consequently, using hard water can reduce the fluid life. Deionized (DI) 

water can be used in place of hard water (DI units can be either purchased or rented). 

Reduction of Contamination from Sumps. EPA has identified the following 

examples of methods to reduce contamination from metal-working fluid sumps: 

� Steam Cleaning of Sumps. Machine coolant sumps harbor bacteria that 

degrade the fluids. If coolant sumps are not sterilized during cleanouts, 

residual bacteria may degrade the fresh coolant added to cleaned sumps. 

Steam cleaning the sumps during cleanout can eliminate bacteria. 

� Sump Modification. Many coolant sumps are designed as in-ground 

concrete tanks, whose porous concrete surfaces absorb oil and promote 

bacterial growth. Improving the design of the sumps can extend fluid life. 

Potential design changes include inserting metal tanks and coating sump 

walls with fiberglass or other nonporous material. 

Reduce Miscellaneous Contamination. Good housekeeping practices can extend 

metal-working fluid life by reducing contamination. Facilities can implement housekeeping 

procedures to keep floor sweepings, solvents, paint chips, soil, rags, paper, and other debris out 

of the coolant sumps. 

D.2.2.2 Extension of Metal-Working Fluid Life 

Facilities can implement several methods to extend the life of metal-working 

fluids. These include raw material substitution, equipment modification, and fluid monitoring, as 

discussed below. 

Raw Material Substitution. As discussed above, four general types of metalworking fluids are used in machining operations. Within a given group of fluids, such as soluble 

oil, various formulations are used. Within each group, the major difference from one fluid to 

another is the “additive package.” Additives are included in most metal-working fluid 

formulations to improve fluid performance (e.g., improve lubricity, reduce friction, or increase 

corrosion protection) and increase life span (e.g., reduce bacterial growth). Costs of different 

D-27

Appendix D - Pollution Prevention and Water Conservation Practices 

metal-working fluids can vary by 100 percent or more. Fluids with additive packages that do not 

meet the lubrication and cooling requirements of the specific machining operation may degrade 

faster than other metal-working fluids. These fluids will need to be replaced more often and 

increase overall operating costs. These fluids may also affect tool life, further increasing 

operating costs. Therefore, using the proper grade metal-working fluids can increase the life 

span of the fluid, reducing the generation of waste machining fluids and decreasing the overall 

operating costs. 

Equipment Modification. EPA has identified the following examples of 

equipment modifications that can extend the life of machining fluids. 

� Replacement of Air Agitation With Mechanical Agitation. Some facilities 

use air agitation in central coolant sumps to constantly mix the fluid and 

prevent phase separation and pooling of tramp oil. However, air agitation 

increases the activity of aerobic bacteria by adding oxygen, which causes 

the bacteria to consume fluid additives. An alternative method of mixing 

is mechanical agitation (i.e., pumping). Mechanical agitation mixes 

without increasing the oxygen concentration of the coolant. 

� Removal of Tramp Oil. Machining fluid life can be extended by 

continuous, in-sump removal of tramp oil. Facilities can install 

continuous oil-skimming devices directly in the machine sump to remove 

tramp oil. Absorbent blankets, fabrics, or pillows can also remove tramp 

oil. 

Fluid Monitoring. During use, the metal-working fluid undergoes various 

physical, chemical, and biological changes. If the properties of the fluid are monitored on a 

regular basis, the fluid can be adjusted before it is degraded. Parameters measured to monitor the 

fluid include: pH, coolant concentration (using a refractometer or titration kit), TDS, tramp oil 

(visual) and biological activity (using dip slides available from coolant suppliers and laboratories 

(6) or other methods). Facilities can use these data to guide periodic fluid adjustments and/or 

develop statistical process control (SPC) procedures. Facilities may wish to monitor fluid 

concentration at least weekly, if not daily, to identify contamination. The correct pH operating 

range of most coolants is 8.5 to 9.5. If the pH drops below the operating range, coolants may 

cause rusting and be prone to increased biological activity. Dilute concentrations can shorten 

tool life, increase biological activity, and cause rust. Rich concentrations can lead to foaming 

and tramp oil contributes to biological growth. 

D.2.2.3 Metal-Working Fluid Recycling 

Most metal-working fluids can be recycled on-site by removing contaminants 

accumulated during use and storage. Recycling methods include settling, straining, skimming, 

simple filtration, membrane filtration, coalescing, centrifugation, cyclone separation, magnetic 

separation, and pasteurization. Some of these methods can be used in combination to recover 

D-28

Appendix D - Pollution Prevention and Water Conservation Practices 

nearly 100 percent of the metal-working fluid. Facilities can purchase recycling equipment or 

hire commercial services that perform on-site processing (10,11,12). A self-contained recycling 

unit can be purchased that is specifically designed for smaller machine shops and is a complete 

sump maintenance and fluid recycling system in one unit (8). In most cases, facilities can 

facilitate metal-working fluid recycling by consolidating the types of machining fluids they use to 

one or two types of fluid. 

Additional metal-working fluid can be recycled by chip drainage. Chip drainage 

can account for up to 50 percent of annual fluid use (11). During machining, the metal chips 

(scraps) become coated with fluid. Part of the fluid drains from the chips and part remains on the 

chips. In many cases, the chips and associated fluid drop to the floor and are manually collected 

in storage containers. Some machines send the chips and fluid to a storage container using 

automated equipment (e.g., belt or pneumatic conveyor). Fluid that drains from chips can be 

recycled rather than discharged, which may require design changes of chip handling and storage 

equipment. 

D.2.2.4 Design of the Machine Fluid System 

Fluids used in machining are stored either in sumps dedicated to individual 

machines (either internal or external to the machine), or in central sumps that serve multiple 

machines. Large machining operations typically use central sumps, whereas small machine 

shops tend to have individual sumps for each machine. Central systems usually contain three to 

five times greater volume of fluid per machine from individual sumps. The reservoir volumes of 

most machines with internal sumps are typically 10 to 50 gallons. External sumps serving a 

single machine typically have a volume of 1,000 to 2,500 gallons. Central sumps may have 

volumes that exceed 50,000 gallons. 

The amount of make-up fluid in a central system amounts to a smaller percentage 

of total fluid than in a single machine operation. Consequently, the potential for bacterial 

degeneration is greater in central systems as the bacteria have a longer time in which to degrade 

the fluid (9). Further, central sumps are often unlined concrete basins, whose porous walls 

harbor bacteria and prevent complete disinfecting during cleanouts. This reduces the time 

needed for the bacteria to become reestablished (11). Additionally, the larger pumps used in 

central systems keep the tramp oils suspended in the fluid so they do not readily “float out,” 

adding to further bacterial attack. Central systems may require more maintenance than dedicated 

sumps to prevent bacterial growth. 

D.2.2.5 Machining Operations Performed 

The ratio of scrap metal (e.g., chips) generated to fluid used varies among 

machining operations. For example, metal cutting may generate large pieces of scrap metal using 

a small volume of fluid, whereas a milling operation usually produces a much smaller mass of 

chips for the same volume of fluid. 

D-29

Appendix D - Pollution Prevention and Water Conservation Practices 

D.2.2.6 Base Material Being Machined 

The type of base material being machined affects the quantity of metal-working 

fluid used. The hardness of base materials varies, which in turn affects the speed at which the 

base metal can be removed. Harder metals require more fluid than softer metals for the same 

operation. 

D.2.2.7 Climatic Conditions 

The temperature of the shop can affect the life span of metal-working fluid in that 

warmer temperatures may foster the growth of certain bacteria. 

D.2.2.8 Design and Age of Machines 

The design and age of machines may affect the quantity of hydraulic oil that is 

leaked to the metal-working fluid during machining operations. Numerous hydraulic systems are 

used with machines. These systems will leak variable amounts of oil depending on design, 

sealing mechanisms, operating pressures, and other factors. Older machines, especially those 

that are not properly maintained, can have hydraulic seals that excessively leak. 

D.2.2.9 Uniform Coolant Use 

Minimizing the number of different machine coolants used at a facility reduces 

the chance of formulation errors. When employees are familiar with fluid properties and coolant 

formulation chemistry, it is less likely that coolant batches will be prepared incorrectly, which 

many times requires the entire batch to be discharged to the on-site wastewater treatment facility. 

Facilities may also save money by purchasing larger volumes of coolant (i.e., economies of 

scale). 

Painting Operations 

Paint is applied to a base material for protective and decorative reasons in various 

forms, including dry powder, solvent-diluted formulations, and water-borne formulations. There 

are various methods of application, the most common being immersion and spraying. Water is 

used in painting operations in paint booth water-wash systems (water curtains), in water-borne 

formulations, in electrophoretic painting solutions and rinses, and in clean-up operations. This 

discussion is directed at water use in spray painting booths; however, this subsection also 

provides some information on rinsing following electrophoretic painting and water clean-up. 

D.3.1 Wastewater Generation from Painting Operations 

In spray painting, an organic coating is applied to a product. During 

manufacturing operations, spray painting is usually performed in a booth to control the 

introduction of contaminants and the release of solvent and paint to the work place and 

D-30


D.3 
Appendix D - Pollution Prevention and Water Conservation Practices 

environment, and to reduce the likelihood of explosions and fires. Paint booths are categorized 

into two types (dry filter or water wash) and by the method of collecting the overspray (i.e., the 

paint that misses the product during application). The type of booth design selected depends 

mainly on production requirements, including part size and configuration, production rate and 

transfer efficiency, the material being sprayed, and finish quality requirements. 

Dry-filter booths use filters to screen out the paint solids, by pulling prefiltered air 

through the booth, past the spraying operation, and through the filter. The air entrains the 

overspray and is pulled through the filter, which collects the paint. Solvent evaporates from the 

paint, leaving the paint solids on the filter. Filters are periodically replaced when they become 

laden with paint solids and the air flow through them is restricted. Dry-filter booths are most 

often used when paint usage does not exceed 20 gallons/8-hour shift/10 feet of chamber width 

(13). At higher usage rates, the frequency of filter changes greatly increases operating costs (i.e., 

filter, filter disposal, cost, and labor). 

The only water used with dry filter units is to clean painting equipment (e.g., guns 

and lines) when water-borne paints are used. The operation of dry-filter units is essentially dry 

when solvent-based paints are used. 

Water-wash booths use a “water curtain” to capture paint overspray. Air 

containing entrained paint overspray is pulled through a circulating water stream, which “scrubs” 

the overspray from the air. There are two primary types of water-wash booths, side-draft and 

downward-draft. The basic difference between the two types is the way the air moves through 

the system to draw the paint overspray in for capture (14,15). Small operations typically use 

side-draft units and large and/or continuous operations use downward-draft units. 

Water-wash booths use a water stream that recirculates from a sump or tank with 

a typical capacity of 200 to 5,000 gallons or more. Downward-draft systems normally contain 

much larger volumes of water than side-draft systems. Water is periodically added to the system 

as make-up for evaporative losses. The sump water is periodically discharged, usually during 

general system cleaning or maintenance. The discharge rate depends on various factors, 

including booth design, paint type, overspray rate, and the water treatment methods used. Water 

is also used to clean the painting equipment and the paint booth. Booth cleanup may involve 

using paint stripper to remove dried paint from the walls of the booth and the piping system. 

A common practice in water-wash booth operation is to immediately detacify 

suspended paint solids to reduce maintenance problems and to subsequently separate and remove 

the solids from the water. The organic resins that make up the bulk of the paint coating are 

insoluble in water and tend to stay tacky if not treated with some other material added to the 

water (14,15). If left untreated, the tacky solids can plug recirculation pipes and pumps and 

adhere to wetted surfaces of the booth. Dissolved solids are either immediately precipitated and 

flocculated, removed by water treatment, or discarded when the sump is discharged. 

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Appendix D - Pollution Prevention and Water Conservation Practices 

Solids can be detacified and removed in various ways, depending on the type of 

paint used and the booth design. Detacification chemicals include sodium hydroxide (caustic), 

metal salts, clay, and polymers. Depending on the type of paint and the detacification chemical, 

the paint solids may either disperse or agglomerate. Agglomerated solids may either sink or 

float. In solids dispersal, the suspended solids increase in concentration as overspray enters the 

water. Subsequently, another chemical is added to the water that causes the dispersed solids to 

agglomerate into a dense floc, which is then removed. 

There are various ways to remove paint solids from the booth water-wash system. 

These removal technologies vary in sophistication, automation, efficiency (removal and 

separation), and capital and operating costs. The most common methods include passive settling, 

skimming, screening, filtration (bag, roll bed, press), and centrifugal methods (hydrocyclone, 

centrifuge). 

Besides spray painting, another common method of painting is electrophoretic 

painting (also known as electrocoating or electrodeposition), which is the process of coating a 

work piece by making it either anodic or cathodic in a bath that is generally an aqueous emulsion 

of the coating material. The electrophoretic painting bath contains stabilized resin, pigment, 

surfactants, and sometimes organic solvents in water. Electrophoretic painting is used primarily 

for primer coats (e.g., bodies for motor vehicles or mobile industrial equipment) because it gives 

a fairly thick, highly uniform, corrosion-resistant coating in relatively little time. During this 

process, precleaned parts carrying an electrical charge are immersed into the coating tank (paint) 

and then through a rinsing system. Rinsing removes excess paint (drag-out) from the parts. The 

typical rinsing procedure is a three-stage countercurrent cascade rinse, and may include both dip 

and spray rinsing. Typically, the final rinse is performed with deionized water. 

Ultrafiltration is commonly used to separate and recover paint solids and recycle 

rinse water, by counter flowing the rinse water into the painting bath and running the bath 

through the ultrafilter. The ultrafilter removes excess water from the bath, recycles the paint 

solids to the bath, and recycles the water (permeate) to the rinse system. Occasional blowdown 

of rinse water is needed to purge the system of contaminants. Processing the rinse water through 

a reverse osmosis unit can reduce the volume of wastewater discharged (16). 

D.3.2 Pollution Prevention and Water Conservation Practices for Painting

Operations

EPA has identified three categories of pollution prevention and water 

conservation practices that, if implemented, can reduce or eliminate wastewater discharges from 

painting operations: practices to reduce the quantity of paint entering the water system; recycling 

technologies for paint booth water; and conversion of water-wash booths to dry-filter booths. 

These are discussed in this subsection and summarized in Table D-11. It is possible, however, 

that facilities can reduce or eliminate wastewater discharges using different practices than those 

described here. 

D-32

Appendix D - Pollution Prevention and Water Conservation Practices 

Table D-11

Potential Pollution Prevention and Water Conservation Methods

Applicable to Painting Operations

Pollution Prevention/Water

Conservation Method Examples Applicability

Reduce the Quantity of Paint Entering the Water System

Improve spray painting 

operating practices 

Provide operator training to improve 

racking and positioning of parts to 

reduce overspray, assure proper 

selection of nozzle for efficient spray 

pattern, improve work scheduling and 

reduce clean-outs, improve 

housekeeping. 

Applicable to all spray painting 

operations. 

Improve paint transfer 

efficiency 

Replace inefficient conventional 

compressed air spray equipment with 

high-velocity/low-pressure equipment. 

Applicable to most existing spray 

painting operations using 

conventional equipment. Will 

require some retraining of 

operators. 

Install gun cleaning station Use gun-cleaning station to clean guns 

and lines. Can prevent spraying of 

cleaning fluid/paint into booth. 

Applicable to most solvent-based 

painting operations. 

Recycle Paint Booth Water

Recycle paint booth water 

through solids removal 

Use booth water maintenance system 

that removes paint solids. Applicable 

technologies include weirs, filters, and 

centrifuges. 

Applicable to most water-wash 

booths. Usually requires 

treatment of booth water with 

chemicals to produce solids that 

can be separated from water. 

Use Dry-Filter Booths

Use dry-filter booths instead 

of water-wash booths 

Convert existing water-wash booth to a 

dry-filter booth. 

Applicable to booths with low to 

moderate paint usage. In cases of 

high paint usage, dry filters clog 

too quickly. 

Source: MP&M Site Visits, MP&M Surveys, Technical Literature. 

D-33

Appendix D - Pollution Prevention and Water Conservation Practices 

D.3.2.1 Reducing the Quantity of Paint Entering the Water System

Facilities can implement various methods to reduce the quantity of paint entering 

the water system. Three of these methods are discussed below. 

Improving Spray Painting Operating Practices. Facilities can implement various 

practices that reduce the quantity of paint and other material entering the water system of a paint 

booth and thereby reduce the need to discharge wastewater. Generally, implementing these 

practices requires only operator training. These practices include: racking and positioning parts 

to minimize overspray; selecting the proper nozzle for an efficient spray pattern; scheduling work 

to reduce color changes and associated clean-outs of guns, lines, and pots; and housekeeping to 

prevent painting wastes and foreign materials from entering the booth’s water system. 

Improving Transfer Efficiency. The transfer efficiency (i.e., spray efficiency) is 

the amount of coating that is applied to the part divided by the amount of coating that is sprayed 

from the gun. It is reported as a percentage. The transfer efficiency depends on several factors, 

including the spraying equipment, part size and configuration, paint type, and operating methods. 

Improving the transfer efficiency can reduce booth water processing requirements. 

During the past 15 to 20 years, spraying equipment has improved, primarily in 

response to more stringent air pollution regulations and rising paint costs. One of the key 

improvements has been replacement of conventional compressed air spray equipment by more 

efficient equipment. In terms of transfer efficiency, the common types of spray equipment are 

ranked as follows (shown in order of increasing efficiency with relative transfer efficiencies 

shown in parenthesis): conventional compressed air (25 percent), airless (35 percent), air 

assisted airless (45 percent), electrostatic, (65 percent), and high-volume/low-pressure (HVLP) 

(80 percent) (17). The HVLP equipment has been widely implemented due to the high transfer 

efficiency, as well as the low cost of converting from conventional compressed air equipment. 

The cost is primarily for the spray guns, since the compressors and other equipment are the same 

as for conventional compressed air painting equipment. 

Installing Gun Cleaning Station. After use, spray-painting equipment must be 

cleaned to prevent a buildup of paint solids. Spray guns are often cleaned by spraying solvent 

through the lines and guns and into the booth. However, this practice increases the amount of 

paint entering the booth’s water system and increases emissions of volatile organic compounds 

(VOCs). An alternative practice is to install gun-cleaning stations. A commercial gun-cleaning 

unit is designed to sit on top of a 55-gallon drum. The gun is connected to the solvent tank and 

the drum. Solvent is drawn through the gun and exits into the drum, where it can be recovered 

by distillation (18). 

D.3.2.2 Booth Water Recycle

Various methods and equipment can reduce or eliminate the discharge of the 

water used in water-wash booths. These methods and equipment prevent the continuous 

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Appendix D - Pollution Prevention and Water Conservation Practices 

discharge of booth waters by conditioning (i.e., adding detacifiers and paint-dispersing polymers) 

and removing paint solids. The least efficient paint booth water-wash system, in terms of water 

use, is one where the paint solids are not conditioned and accumulate until booth water must be 

replaced. Cleaning such systems typically involves draining or pumping the water from the 

booth reservoir and contract hauling the entire waste product. Due to high operating costs and 

downtime, this procedure is usually used only by low-production operations. Moderate- and 

high-production operations need daily, if not continuous, booth water maintenance to conserve 

water. The most basic form of booth water maintenance is removing paint solids by manual 

skimming and/or raking. These solids can be removed without water conditioning since some 

portion of solvent-based paints usually floats and/or sinks. With the use of detacifiers and paintdispersing polymer treatments, facilities can implement more advanced methods of solids 

removal. Some common methods are discussed below. 

Wet-Vacuum Filtration. Wet-vacuum filtration units consist of an industrial wetvacuum head on a steel drum containing a filter bag. The unit vacuums paint sludge from the 

booth. The solids are filtered by the bag and the water is returned to the booth. Large vacuum 

units are also commercially available that can be moved from booth to booth by forklift or 

permanently installed near a large booth. 

Tank-Side Weir. A weir attached to the side of a side-draft booth tank allows 

floating material to overflow from the booth and be pumped to a filtering tank for dewatering 

(14,15). 

Consolidator. A consolidator is a separate tank into which booth water is 

pumped. The water is then conditioned by adding chemicals. Detacified paint floats to the 

surface of the tank, where it is skimmed by a continuously moving blade. The clean water is 

recycled to the booth (14,15). 

Filtration. Various types of filtration units are used to remove paint solids from 

booth water. The booth water is pumped to the unit where the solids are separated, and the water 

is returned to the booth. The simplest filtration unit consists of a gravity filter bed with paper or 

cloth media. Vacuum filters are also used, some of which require precoating with diatomaceous 

earth (14,15). 

Centrifuge Methods. Two common types of centrifugal separators are the 

hydrocyclone and the centrifuge. The hydrocyclone is used to concentrate solids. The paint 

booth water enters a cone-shaped unit under pressure and spins around the inside surface. The 

spinning increases the gravity, which causes most of the solid particles to be pulled outward to 

the walls of the cone. Treated water exits the top of the unit and the solids exit the bottom. 

Some systems have secondary filtration devices to further process the solids. The centrifuge 

works in a similar manner, except that the booth water enters a spinning drum, which imparts the 

centrifugal force needed to separate the water and solids. Efficient centrifugation requires close 

control of the booth water chemistry to assure a uniform feed. Also, auxiliary equipment such as 

booth water agitation equipment may be needed. 

D-35

Appendix D - Pollution Prevention and Water Conservation Practices 

D.3.2.3 Conversion of Water-Wash Booths to Dry-Filter Booths 

Water-wash booths can be converted to or replaced by dry-filter booths. The dryfilter booths have the potential to eliminate the wastewater discharge, but they create a solid 

wastestream. The choice between using a water-wash booth or a dry-filter booth is primarily 

based on the amount of overspray. It is usually cost-effective to use a dry-filter booth when paint 

usage does not exceed 20 gallons/8-hour shift/10 feet of chamber width (13). 

A 1989 U.S. Navy study concluded that conversion from wet to dry booths can be 

cost-effective for a range of operations. This study included a survey of military and industrial 

facilities that have successfully converted and an economic analysis based on typical Navy 

painting operational parameters (1). 

D.3.3 Solvent, Paint Solids, and Other Components of Paint 

The chemical make-up of the paint can impact wastewater generation. The 

recirculated water in a water-wash booth contains the various constituents of the paint(s) being 

applied. With most solvent formulations, the solvents (e.g., xylene, toluene, methylene chloride) 

are not water-soluble, but can be water-miscible. Some exceptions, such as acetone and methyl 

ethyl ketone (MEK), are water-soluble. However, in most cases, the solvents are volatile and 

evaporate over time and exit the booth through the air exhaust system. The organic resins that 

make up the bulk of the paint coating are insoluble in water and tend to stay tacky if not treated 

with some additional material introduced to the water (14,15). If left untreated, the tacky solids 

can plug recirculation pipes and pumps and adhere to wetted surfaces of the booth. Other paint 

additives, such as wetting agents, pigments, and heavy metals (e.g., zinc and chromium salts) 

may be soluble in water. These constituents can be made partly insoluble and removed by 

adjusting the chemistry of the water. 

Water-based paints present two problems with regard to water use. First, these 

paints disperse in water rather than agglomerate like solvent-based paints, making the 

maintenance of paint booth waters more difficult (14,15). Second, water is used to clean 

spraying equipment when water-based paints are applied, which may generate wastewater. A 

typical equipment-cleaning procedure is to flush with water, then solvent, then water (2). 

D.3.4 Paint Booth Maintenance Requirements 

Water-wash paint booths are periodically shut down for maintenance, which 

usually involves removing the water in the booth. Various conditions can exist that may 

necessitate discharging the water, including odor, bacterial growth, foaming, TDS buildup, and 

the presence of corrosion and scale constituents. 

Booth maintenance typically involves incidental repairs and cleaning the booth 

surfaces and piping system. Often facilities do maintenance according to a schedule, but periodic 

repairs may also necessitate an unplanned shut-down and clean-out. A common clean-out 

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Appendix D - Pollution Prevention and Water Conservation Practices 

procedure is to remove the accumulated paint solids from the water, transfer the water to a 

holding tank, and return the water after the maintenance is completed. Alternate methods are 

draining the booth water to a sewer or wastewater treatment system or having it hauled to a 

disposal site. Systems with accumulated paint solids on the wetted surfaces of the booth and in 

the piping system can be cleaned by circulating an alkaline cleaner or other chemical for 

dissolving paint. Since the amount of water discharged from water-wash paint booths is a 

function of the system’s maintenance requirements, newer systems that require less maintenance 

will discharge less water. Therefore, one pollution prevention option for water-wash paint 

booths is to install new systems or upgrade existing systems to limit maintenance requirements. 

Cleaning Operations 

Cleaning operations include aqueous degreasing, acid treatment, alkaline 

treatment, and electrolytic cleaning. Depending on the chemicals, equipment, and procedures 

used, these processes are commonly referred to as immersion, spray, or electrolytic alkaline 

cleaning; immersion, spray, or electrolytic acid cleaning or pickling; ultrasonic cleaning; and 

emulsion cleaning and parts washing. 

Many MP&M facilities implement pollution prevention and water conservation 

methods and technologies that result in low cleaning wastewater discharge rates, and in some 

cases, eliminate the discharge of cleaning solutions. Pollution prevention and water conservation 

practices are applicable to all cleaning operations; however, process-related factors and sitespecific conditions may restrict the utility of certain methods. This subsection identifies 

pollution prevention and water conservation practices and technologies applicable to cleaning 

operations. 

D.4.1 Wastewater Generation From Cleaning Operations 

MP&M facilities commonly perform cleaning as a stand-alone operation or in 

combination with other proposed MP&M operations such as anodizing, electroplating, 

conversion coating, and painting. Cleaning removes surface contaminants that affect the 

appearance of parts or the ability to further process the parts. Various types of acidic and 

alkaline solutions are used for cleaning. 

Alkaline cleaners are usually impacted by organic pollutants such as oil and 

grease. The effectiveness of most alkaline cleaners is reduced when the oil concentration of the 

bath is in the range of 1 to 5 g/L or more. Oil and grease enters the alkaline cleaning bath on the 

parts being processed. The rate of oil buildup depends on the production rate (measured in 

square feet per day) and the quantity and characteristics of the contamination on the parts. Acid 

treatment solutions and, to a lesser extent, alkaline treatment solutions accumulate dissolved 

metals from corrosion of the base metals being processed. The dissolved metal reduces the 

strength of the cleaning bath. As dissolved metal increases, additional acid or alkaline solution is 

added; however, at certain metal concentrations, the bath is no longer usable. The tolerable 

concentration of dissolved metals depends mostly on the type of acid or alkaline solution and the 

D-37


D.4 
Appendix D - Pollution Prevention and Water Conservation Practices 

function of the bath. The buildup rate of dissolved metal depends primarily on the production 

rate, type and concentration of acid or alkaline solution, type of base metal, duration of cleaning 

cycle, and bath temperature. 

D.4.2 	 Pollution Prevention and Water Conservation Practices for Cleaning 

Operations 

EPA identified three categories of pollution prevention and water conservation 

practices that, if implemented, can reduce or eliminate wastewater discharges from cleaning 

operations: housekeeping and maintenance, oil and suspended solids removal, and dissolved 

solids removal. These are discussed in this subsection and summarized in Table D-12. It is 

possible, however, that facilities can reduce or eliminate wastewater discharges using different 

practices than those described here. 

Table D-12 

Potential Pollution Prevention and Water Conservation Methods 

Applicable to Cleaning Operations 

Pollution 

Prevention/Water 

Conservation Method Examples Applicability 

Housekeeping and 

maintenance 

Check the accuracy of temperature 

controls; remove sludge build-up from 

tanks, heat coils and temperature 

regulators; retrieve parts, racks, etc. 

dropped into the tanks; and check the 

integrity of tanks and tank liners. 

Applicable to all cleaning operations. 

Oil and suspended solids 

removal 

Technologies used to remove oil and 

suspended solids from cleaning solutions, 

thereby extending the useful life span of 

the solutions (e.g., skimmers, coalescers, 

cartridge and membrane filters). 

Suspended solids removal equipment 

(e.g., cartridge filters) are applicable 

to nearly all baths. The other types of 

equipment are applicable to most or 

all alkaline cleaning baths. 

Dissolved solids removal Various technologies and processes that 

remove dissolved metals from baths, 

including acid sorption, diffusion dialysis, 

and membrane electrolysis. 

Applicable to acid and alkaline 

solutions that become contaminated 

with dissolved metal, usually due to 

etching of the basis metal. 

Source: MP&M Site Visits, MP&M Surveys, Technical Literature. 

D-38

Appendix D - Pollution Prevention and Water Conservation Practices 

D.4.2.1 Housekeeping and Maintenance 

Facilities can implement various housekeeping and maintenance practices to 

reduce the quantity of cleaning solution discharge. Several of these practices are discussed 

below. 

Solution Testing. The chemical make-up of cleaning solutions changes over time 

due to evaporative losses, water additions, cleaning chemical drag-out, chemical reactions, and 

drag-in of impurities. Because of these factors, cleaning baths lose strength, performance 

declines, and solutions require disposal. Many facilities operate cleaning baths on a three-step 

schedule: formulate, use, and discard. This procedure can be expensive and inefficient from a 

production standpoint, and generates large volumes of wastewater. For this reason, facilities 

should frequently test the strength of the cleaning solution and appropriate chemical additions 

needed to continue using the solution. By implementing testing and recordkeeping, facilities can 

reduce the disposal frequency of cleaning baths. 

Most alkaline cleaning solutions are proprietary formulations, and the vendors of 

these solutions provide test methods for determining the condition of a bath. Also, commercial 

test kits are available that include generic test methods. For example, the strength of an alkaline 

cleaning solution can be tested using acid-base titration, which measures alkalinity. Also, there 

is a dual test method that indirectly measures the level of contamination in the cleaner. This 

process consists of titrating a measured sample of cleaner (e.g., 5 milliliters (ml) and then adding 

a color indicator (phenolphthalein or methyl orange) with an acid of precise concentration (e.g., 

1N solution of sulfuric acid). Phenolphthalein is used as the indicator to measure free alkalinity 

and methyl orange is used to measure total alkalinity. By performing both tests, the ratio of total 

alkalinity to free alkalinity can be calculated. A ratio close to 1 indicates that the cleaner is 

relatively free of contamination, while a higher ratio indicates that contamination exists. 

Facilities sometime use this ratio to determine if they should discharge a cleaning solution. For 

example, a common guideline used is that the solution is discarded when the ratio exceeds 2.0. 

The total alkalinity/free alkalinity test method does not work for all cleaners. Because of 

additives used, some alkaline cleaners do not have any free alkalinity. In such cases, the facility 

may want to perform more detailed tests to accurately determine the contaminant concentration 

(e.g., oil and grease measurement). 

Similar test methods exist for acid cleaners. The most common parameters in 

acid cleaner test programs are acid concentration and dissolved metal concentration. The 

concentration of sulfuric acid or hydrochloric acid in pickling solutions is usually measured by 

titrating a sample of the solution with sodium carbonate and using a methyl orange indicator. 

Iron and other dissolved metals can also be measured by titration or by using laboratory 

analytical equipment such as an atomic adsorption spectrophotometer. 

Recordkeeping. Maintaining accurate records of bath additive rates and bath lives 

can help facilities identify trends in solution use and focus on extending the lives of those that are 

D-39

Appendix D - Pollution Prevention and Water Conservation Practices 

frequently discarded. Important records to keep are occurrences of chemical additions and 

solution dumps, production throughput, and chemical concentration data. 

Miscellaneous Housekeeping and Maintenance. To obtain consistently good 

cleaning results and reduce their solution discharge, facilities should implement a regular 

schedule of housekeeping and maintenance. Tasks should include: checking the accuracy of 

temperature controls; removing sludge buildup from tanks, heating coils, and temperature 

regulators; retrieving parts, racks, and other foreign materials dropped into the tanks; and 

checking the integrity of tanks and tank liners. 

D.4.2.2 Oil and Suspended Solids Removal 

Cleaning baths accumulate oil and suspended solids during use. These 

contaminants eventually reach a concentration that interferes with the effectiveness of the 

cleaning process, despite the fact that most bath constituents remain usable. Also, contaminated 

cleaning baths may carry over contaminants to subsequent process solutions. As a result, 

cleaning baths are often discarded when they reach a certain concentration of contaminants. 

There are several technologies used to remove oil and suspended solids from cleaning solutions, 

thereby extending the useful life of the solutions. These technologies are primarily applicable to 

alkaline cleaning baths and are discussed below. 

Free/Floating Oil Separation Devices. Separation devices for oil/water mixtures 

use the difference in specific gravity between oils and water to remove free or floating oil from 

wastewater. Common separation devices for cleaning solutions include skimming devices 

(disks, belts, and rotating drum oil skimmers) and coalescers. These devices are not suited for 

emulsified oil removal, which typically is addressed through chemical treatment or membrane 

filtration. 

Skimming is a simple method of separating floating oil from cleaning solutions. 

Skimming devices are typically mounted onto the side of a tank and operate on a continuous 

basis. The disk skimmer is a vertically rotating disk (typically 12 to 24 inches in diameter) that is 

partially submerged into the liquid of a tank (typically 4 to 12 inches below the surface). The 

disk continuously revolves between spring-loaded wiper blades that are located above the 

surface. The adhesive characteristics of the floating oil cause it to adhere to the disk. As the disk 

surface passes through the wiper blades, the oil is removed and diverted to a run-off spout for 

collection. Maximum skimming rates typically range from 2 to 10 gallons per hour of oil. Belt 

and drum skimmers operate similarly, with either a continuous belt or drum rotating partially 

submerged in a tank. As the surface of the belt or drum emerges from the liquid, the oil that 

adheres to its surface is scraped (drum) or squeezed off (belt) and diverted to a collection vessel. 

Coalescers separate liquids with specific gravity differences of 0.09 and greater. 

Coalescers are typically tanks containing a coalescing media that accelerates phase separation 

(3). A suction skimmer removes cleaning solution and oil from the process tank and pumps it to 

the coalescer. The media in the coalescers is a material such as polypropylene, ceramic, or glass 

D-40

Appendix D - Pollution Prevention and Water Conservation Practices 

that attracts oil in preference to water (i.e., oleophilic). The oil/cleaner mixture passes through 

the unit and the oil adheres to the coalescing media. The oil forms droplets that conglomerate 

and rise to the surface of the tank, where a skimming device or weir removes them. According to 

Stoke’s Law, the rise/fall velocity of a dispersed-phase droplet is exponentially increased with 

the droplet size. Therefore, the coalescing media separates the phases more rapidly than a 

common gravity settling device. 

Media Filtration Methods. Filtration removes suspended solids from cleaning 

solutions. Common types of filters include cartridge filters, precoat diatomaceous earth filters, 

and sand or multimedia filters. Cartridge filters are available with either in-tank or external 

configurations; the in-tank filters typically are used for small tanks and the external filters for 

larger tanks. Most cartridges are disposable; however, washable and reusable filters are 

available, which further reduce waste generation. Precoat, sand, and multimedia filters are used 

mostly for large tank applications. The type of filter media used is based on the chemical 

composition of the bath. All filtration systems are sized based on solids loading and the required 

flow rate. Typical flow rates for cleaning solution applications are two to three bath turnovers 

per hour. 

Membrane Filtration. Microfiltration and ultrafiltration are membrane-based 

technologies used primarily to remove emulsified oil and other colloids from cleaning solutions. 

The solution entering a microfiltration or ultrafiltration unit typically is prefiltered using media 

filters to remove large particulates. Various devices then trap or skim floating oils and allow 

heavier solids to settle. The solution is pumped into the membrane compartment, where the 

membrane traps remaining oil and grease while water, solvent and other cleaning bath 

constituents pass through. The fluid flows parallel to the membrane with enough velocity to 

remove the reject from the membrane surface. Ceramic membranes are available in various pore 

sizes ranging from several hundred angstroms to over 0.2 microns. The appropriate pore size is 

determined by the specific cleaner to be filtered. The capacity of a unit is based on the total area 

and flux rate of the membrane. Commercially available units range in capacity from less than 

260 to more than 1,300 gallons per day. 

D.4.2.3 Dissolved Metals Removal 

Metals become dissolved in acid and alkaline cleaning solutions as a result of 

corrosion of the base metal. The dissolved metal forms salts or other compounds that reduce the 

strength of the cleaning bath. Technologies used to remove dissolved metals include acid 

sorption, diffusion dialysis, and membrane electrolysis, discussed below. 

Acid Sorption. Acid sorption is an acid purification technology that is applicable 

to various acid treatment solutions, as well as other acidic baths (e.g., anodizing baths). The acid 

sorption unit resembles an ion-exchange column. The column contains a bed of alkaline anion 

exchange resin that separates the acid from the metal ions. 

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Appendix D - Pollution Prevention and Water Conservation Practices 

First, spent acid is pumped upward through the resin; the acid is absorbed by the 

resin while the metal ions pass through it. The resulting metal-rich, mildly acidic solution is 

collected at the top of the bed. Water is then pumped downward through the bed and desorbs the 

acid from the resin. The purified acid solution is collected at the bottom of the bed. This 

technology can recover approximately 80 percent of the free acid remaining in a spent acid 

treatment solution. Purification can be performed in a batch mode, but is most effective in a 

continuous flow mode (usually expressed in terms of the mass of metal removed from the acid 

solution per unit of time). Equipment capacity ranges from 100 grams/hour to several thousand 

grams/hour. Units are sized to remove metal near or above the rate at which the metal is being 

introduced. Typically, a facility determines a target level of metal concentration and sizes the 

unit to maintain that level. 

Diffusion Dialysis. Diffusion dialysis is a membrane process that separates metal 

contaminants from the acid solution using an acid concentration gradient between solution 

compartments. Anion exchange membranes makeup the compartments. The membranes are 

usually assembled in a membrane stack, like that used with electrodialysis. The contaminated 

acid passes through one set of compartments and deionized water through the adjacent 

compartments. Acid is diffused across the membrane into the deionized water whereas metals 

are blocked due to their charge and the selectivity of the membrane. Unlike electrodialysis, this 

process uses no electrical potential. The acid diffuses because of the difference in acid 

concentration on either side of the membrane (i.e., material in high concentration moves to an 

area of low concentration). 

Membrane Electrolysis. Membrane electrolysis is a bath maintenance technology 

that lowers or maintains the concentration of metallic impurities in cleaning solutions. This 

technology is also applicable to other metal-bearing solutions (e.g., electroplating, anodizing, and 

stripping solutions). This technology uses an ion-exchange membrane(s) and an electrical 

potential applied across the membrane(s). The membrane is ion-permeable and selective, 

permitting ions of a given electrical charge to pass through. Cation membranes allow only 

cations (e.g., copper, nickel, aluminum) to pass from one electrolyte to another, while anion 

membranes allow only anions (e.g., sulfates, chromates, chlorides, cyanide) to pass through. 

Bath maintenance units can be configured with cation or anion membranes, or both. 

A typical application of membrane electrolysis is maintenance of an acid cleaning 

solution. The cleaning solution is placed in an anode compartment that is separated from a 

second electrolyte by a cation membrane. The solution in the cathode compartment (i.e., 

catholyte) is typically a dilute acidic or alkaline solution. When an electrical potential is applied, 

the dissolved metals in the cleaning solution migrate through the cation membrane into the 

catholyte. The catholyte is periodically discarded when it becomes saturated with metals. 

D-42

Appendix D - Pollution Prevention and Water Conservation Practices 

D.4.3 Condition of the Surfaces Being Cleaned 

The condition of the parts being cleaned varies widely, both in terms of the types 

and quantities of contaminants present and the quantity of oil. For example, some parts may 

have been wiped clean and have only a light deposit of metal-working fluids, while other parts 

may be heavily coated. Since metal-working fluids (oils) present on the parts are removed during 

the cleaning process (aqueous degreasing), the rate of oil that is entering into the cleaning 

solution per square foot of part cleaned will vary. The type of oil entering the cleaning solution 

will also affect the cleaning fluid’s life-span. 

D.4.4 Cleaning Requirements 

Some processes, such as electroplating, require a high degree of cleanliness while 

others, such as phosphate conversion coating, may have less stringent requirements. The 

cleaning requirements will therefore vary within a facility, as well as from facility to facility, as 

will the type of cleaning process selected. 

Some cleaning processes are more amenable to pollution prevention practices than 

others, based on the purpose of the cleaning process. For example, many electroplating 

processes require etching of the part’s surface to enhance adhesion of the electroplated metal 

deposit. Surface etching introduces dissolved metal into the cleaning solution and will reduce its 

life-span. 

D.4.5 Type of Cleaning Process and Equipment 

The life-span of cleaning solutions depends on the type of cleaning process (i.e., 

process chemistry and cleaning equipment). Numerous factors affect the selection of a cleaning 

process, including: type and characteristics of contaminants to be removed; type and condition of 

base metal; size and configuration of parts; degree of cleanliness required; processing capabilities 

at the site; subsequent operations to be performed; and financial considerations. 

The factors that most affect the selection of process chemistry and equipment are 

the type of contaminants present on the parts, type of base metal, and the subsequent finishing 

operation, which in turn dictate the cleaning requirements. Contaminants present on parts can 

include both organic and inorganic contaminants. Examples of organic contaminants are 

machining fluids, miscellaneous oils, waxes, and buffing compounds, which are typically 

removed by solvents, detergents, and alkaline solutions. Examples of inorganic contaminants are 

scale, smut, and grinding residue, which are typically removed by acidic solutions. Various 

methods are used to apply the cleaning solution. For example, solutions can be applied by 

spraying or immersing, and can be applied electrolytically (including both anodic and cathodic 

cleaning). Application method is primarily based on the concentration and condition of the 

contaminant and the configuration of the parts. 

D-43

Appendix D - Pollution Prevention and Water Conservation Practices 

The base material of the parts is also a consideration in selecting a cleaning 

process. Some base materials are chemically or physically altered by certain cleaning steps 

because of oxidation, etching, activation, and hydrogen embrittlement. Such changes may be 

either desirable or damaging. The base material is also important in considering the operating 

conditions of the cleaning process (e.g., concentration, temperature, current). Further, the base 

material contaminates the cleaning solution (e.g., etching during acid treatment) and therefore 

affects the life span of the solution. 

References 

1.	 Ayer, Jacqueline and McElligott, Anthony. “Navy Paint Booth Conversion 

Feasibility Study (CR 89.004).” Naval Civil Engineering Laboratory, January 

1989. 

2.	 Joseph, Ron. “Low-VOC Waterborne Coatings,” Metal Finishing Organic 

Finishing Guidebook and Directory Issue for ‘94. Metal Finishing. Hackensack, 

NJ, May 1994. 

3.	 Batutis, Edward, F. “Keep Your Cleaners Clean,” Products Finishing. October 

1989. 

4.	 Kushner, Joseph B. Water and Waste Control for the Plating Shop. Gardner 

Publications, Inc., 1976. 

5.	 Cushnie, George C. Pollution Prevention and Control Technology for Plating 

Operations. National Center for Manufacturing Sciences, 1994. 

6.	 Lownheim, Frederick A. Electroplating Fundamentals of Surface Finishing. 

McGraw-Hill Book Co., New York, NY, 1978. 

7.	 Murphy, Michael, Ed. Metal Finishing Guidebook and Directory Issue for 1994. 

Metal Finishing. Hackensack, NJ, 1994. 

8.	 University of Northern Iowa. Cutting Fluid Management in Small Machine Shop 

Operations. Iowa Waste Reduction Center, Cedar Falls, Iowa, undated. 

9. Master Chemical Corporation. A Guide to Coolant Management. 

10.	 Higgins, Thomas. Hazardous Waste Minimization Handbook. Lewis Publishers, 

Chelsa, MI, 1989. 

11.	 Ebasco Environmental. Hazardous Waste Minimization Study, Air Force Plant 

No. 6. Final Report, Norcross, GA, 1992. 

D-44


D.5 
Appendix D - Pollution Prevention and Water Conservation Practices 

12.	 Freeman, H.M. Standard Handbook of Hazardous Waste Treatment and Disposal. 

McGraw-Hill, New York, NY, 1989. 

13.	 Thomas, Barry, “Spray Booths,” Metal Finishing Organic Finishing Guidebook 

and Directory Issue for ‘94. Metal Finishing. Hackensack, NJ, May 1994. 

14.	 Monken, Alan. “Wastewater Treatment Systems for Finishing Operations,” Metal 

Finishing Organic Finishing Guidebook and Directory Issue for ‘94. Metal 

Finishing. Hackensack, NJ, May 1994. 

15.	 Monken, Alan. “Water Pollution Control for Paint Booths,” Metal Finishing 

Organic Finishing Guidebook and Directory Issue for ‘94. Metal Finishing. 

Hackensack, NJ, May 1994. 

16.	 Brewer, George. “Electrodeposition of Organic Coatings,” Metal Finishing 

Organic Finishing Guidebook and Directory Issue for ‘94. Metal Finishing. 

Hackensack, NJ, May 1994. 

17.	 Marg, Ken. “HVLP Spray Puts You into Compliance.” Metal Finishing. March 

1989. 

18.	 Lighthall Industries, LighthallTM SC 70 Gun Cleaner, Lighthall Industries, Santa 

Cruz, CA. 

D-45

Appendix E - Modified Delta-Lognormal Distribution 

Appendix E

MODIFIED DELTA-LOGNORMAL DISTRIBUTION
Appendix E - Modified Delta-Lognormal Distribution 

Appendix E 

MODIFIED DELTA-LOGNORMAL DISTRIBUTION 

This appendix describes the use of the modified delta-lognormal distribution to model 

treated effluent data and the estimation of the episode long-term averages and variability factors used to 

calculate the limitations and standards.1 This appendix describes the statistical methodology that was 

used to obtain the results presented in Section 10.0. 

The modified delta-lognormal distribution is a generalization of the familiar two 

parameter lognormal distribution. This generalized model can be used to model data sets that are a 

mixture of lognormally distributed values and values that are censored and/or assigned a constant value 

such as zero or a sample-specific detection limit. When only measured (i.e., noncensored) values are 

present in the data, such as all the data sets used to determine the limitations, the modified deltalognormal distribution is equivalent to the familiar two parameter lognormal distribution. Researchers 

have concluded that the lognormal distribution is often useful for environmental data.2,3 Furthermore, 

EPA has found that the lognormal consistently provides a reasonably good fit to observed effluent data 

distributions.4 In this appendix, EPA has described the full model, that is, the modified delta-lognormal 

distribution, because it was used to calculate some of the loadings used in other analyses supporting this 

rule. This model has been used to develop effluent limitations for currently regulated industries including 

the Iron and Steel industry and the Centralized Waste Treatment industry. 

Basic Overview of the Modified Delta-Lognormal Distribution 

EPA selected the modified delta-lognormal distribution to model pollutant effluent 

concentrations from the MP&M industry in developing the long-term averages and variability factors. A 

typical effluent data set from a sampling episode or self-monitoring episode (see Section 3.0 for a 

discussion of the data associated with these episodes) consists of a mixture of measured (detected) and 

nondetected values. The modified delta-lognormal distribution is appropriate for such data sets because 

it models the data as a mixture of measurements that follow a lognormal distribution and nondetect 

measurements that occur with a certain probability. The model also allows for the possibility that 

nondetect measurements occur at multiple sample-specific detection limits. Because the data appeared 

1

In the remainder of this appendix, references to ‘limitations’ includes ‘standards.’ 

2

e.g., see Richard O. Gilbert, Statistical Methods for Environmental Pollution Monitoring, Van Nostrand Reinhold, 

New York, 1987. 

3

W.J. Owen and T.A. DeRouen, “Estimation of the Mean for Lognormal Data Containing Zeroes and Left-Censored 

Values, with Applications to the Measurement of Worker Exposure to Air Contaminants,” Biometrics 36:707-719, 

1980. 

4

See H.D. Kahn and M.B. Rubin, “Use of Statistical Methods in Industrial Water Pollution Control Regulations in the 

United States,” Environmental Monitoring and Assessment, 12: 129-148, 1989. 

E-1 

E.1 
Appendix E - Modified Delta-Lognormal Distribution 

to fit the modified delta-lognormal model reasonably well, EPA has determined that this model is 

appropriate for these data. 

The modified delta-lognormal distribution is a modification of the ‘delta distribution' 

originally developed by Aitchison and Brown.5 While this distribution was originally developed to model 

economic data, other researchers have shown the application to environmental data.6 The resulting 

mixed distributional model, which combines a continuous density portion with a discrete-valued spike at 

zero, is also known as the delta-lognormal distribution. The delta in the name refers to the proportion of 

the overall distribution contained in the discrete distributional spike at zero; that is, the proportion of zero 

amounts. The remaining nonzero, noncensored (NC) amounts are grouped together and fit to a 

lognormal distribution. 

EPA modified this delta-lognormal distribution to incorporate multiple detection limits. 

In the modification of the delta portion, the single spike located at zero is replaced by a discrete 

distribution made up of multiple spikes. Each spike in this modification is associated with a distinct 

sample-specific detection limit associated with nondetected (ND) measurements in the database.7 A 

lognormal density is used to represent the set of measured values. This modification of the deltalognormal distribution is illustrated in Figure 1. 

5

Aitchison, J. and Brown, J.A.C. (1963) The Lognormal Distribution. Cambridge University Press, pages 87-99. 

6

Owen, W.J. and T.A. DeRouen. 1980. “Estimation of the Mean for Lognormal Data Containing Zeroes and LeftCensored Values, with Applications to the Measurement of Worker Exposure to Air Contaminants.” Biometrics, 

36:707-719. 

7

Previously, EPA had modified the delta-lognormal model to account for nondetected measurements by placing the 

distributional “spike” at a single positive value, usually equal to the nominal quantitation limit, rather than at zero. 

For further details, see Kahn and Rubin, 1989. This adaptation was used in developing limitations and standards for 

the organic chemicals, plastics, and synthetic fibers (OCPSF) and pesticides manufacturing rulemakings. EPA has 

used the current modification in several, more recent, rulemakings. 

E-2 
Appendix E - Modified Delta-Lognormal Distribution 

Figure 1 

The following two subsections describe the delta and lognormal portions of the modified 

delta-lognormal distribution in further detail. 

Continuous and Discrete Portions of the Modified Delta-Lognormal Distribution 

The discrete portion of the modified delta-lognormal distribution models the nondetected 

values corresponding to the k reported sample-specific detection limits. In the model, * represents the 

proportion of nondetected values in the dataset and is the sum of smaller fractions, * i, each representing 

the proportion of nondetected values associated with each distinct detection limit value. By letting Di 

equal the value of the ith smallest distinct detection limit in the data set and the random variable XD 

represents a randomly chosen nondetected measurement, the cumulative distribution function of the 

discrete portion of the modified delta-lognormal model can be mathematically expressed as: 

1

Pr ( X D £ c) = d � d i 0 < c (E-1) 

i:Di £ c 

The mean and variance of this discrete distribution can be calculated using the following formulas: 

1 k 

E ( X D ) = � di Di (E-2) d i =1 

k 2 

Var ( X D ) = 

1 � di(Di - E ( X D )) (E-3) d i =1 

E-3 

E.2 
Appendix E - Modified Delta-Lognormal Distribution 

The continuous, lognormal portion of the modified delta-lognormal distribution was used 

to model the detected measurements from the MP&M industry database. The cumulative probability 

distribution of the continuous portion of the modified delta-lognormal distribution can be mathematically 

expressed as: 

Pr[ X C £ c] = F Ø

Œ 

ln(c) - m ø

œ (E-4) o s ß 

where the random variable XC represents a randomly chosen detected measurement, M is the standard 

normal distribution, and : and F are parameters of the distribution. 

The expected value, E(XC), and the variance, Var(XC), of the lognormal distribution can 

be calculated as: 

� 2 � E ( X C ) = exp� m + 

s 

2 ł

� (E-5) Ł 

Var ( X C ) = [ E ( X C )] 2 ( exp(s 2 ) -1) (E-6) 

Combining the Continuous and Discrete Portions 

The continuous portion of the modified delta-lognormal distribution is combined with the 

discrete portion to model data sets that contain a mixture of nondetected and detected measurements. It 

is possible to fit a wide variety of observed effluent data sets to the modified delta-lognormal 

distribution. Multiple detection limits for nondetect measurements are incorporated, as are measured 

("detected") values. The same basic framework can be used even if there are no nondetected values in 

the data set (in this case, it is the same as the lognormal distribution). Thus, the modified delta-lognormal 

distribution offers a large degree of flexibility in modeling effluent data. 

The modified delta-lognormal random variable U can be expressed as a combination of 

three other independent variables, that is, 

U = I u X D + (1 - I u ) X C (E-7) 

where XD represents a random nondetect from the discrete portion of the distribution, XC represents a 

random detected measurement from the continuous lognormal portion, and Iu is an indicator variable 

signaling whether any particular random measurement, u, is nondetected or noncensored (that is, Iu=1 if 

u is nondetected; Iu=0 if u is noncensored). Using a weighted sum, the cumulative distribution function 

from the discrete portion of the distribution (equation 1) can be combined with the function from the 

E-4

E.3 
� � � � 

Appendix E - Modified Delta-Lognormal Distribution 

continuous portion (equation 4) to obtain the overall cumulative probability distribution of the modified 

delta-lognormal distribution as follows, 

Pr (U £ c) = � d i + (1- d )FŒ

Ø ln(c) - m ø

œ (E-8) 

i:Di £c o s ß 

where Di is the value of the ith sample-specific detection limit. 

The expected value of the random variable U can be derived as a weighted sum of the 

expected values of the discrete and continuous portions of the distribution (equations 2 and 5, 

respectively) as follows 

E (U ) = d E ( X D ) + (1 - d ) E ( X C ) (E-9) 

In a similar manner, the expected value of the random variable squared can be written as 

a weighted sum of the expected values of the squares of the discrete and continuous portions of the 

distribution as follows 

2 2 E (U 2 ) = d E ( X D ) + (1-d )E ( X C ) (E-10)

Although written in terms of U, the following relationship holds for all random variables, U, XD, and XC. 

E (U 2 ) = Var (U ) + [ E (U )] 2 (E-11) 

So using equation 11 to solve for Var(U), and applying the relationships in equations 9 and 10, the 

variance of U can be obtained as 

2 2 2 Var(U ) = d Ł

�Var( XD ) + [E( XD )] ł� + (1- d )

Ł

� Var( XC ) + [ E( XC )] ł� - [ E(U)] (E-12)

Episode-specific Estimates Under the Modified Delta-Lognormal Distribution 

In order to use the modified delta-lognormal model to calculate the limitations, the 

parameters of the distribution are estimated from the data. These estimates are then used to calculate 

the limitations. 

The parameters d

$ 

i and d$ are estimated from the data using the following formulas: 

E-5

E.4 
Appendix E - Modified Delta-Lognormal Distribution 

nd 

d

$ 

i = 

1 � I(d j = Di ) n j=1 (E-13) 

d

$ 

= 

nd 

n 

where nd is the number of nondetected measurements, dj, j = 1 to nd, are the detection limits for the 

nondetected measurements, n is the number of measurements (both detected and nondetected) and 

I(...) is an indicator function equal to one if the expression within the parentheses is true and zero 

otherwise. The "hat" over the parameters indicates that they are estimated from the data. When all of 

the data are noncensored,d

$ is equal to zero and the modified delta-lognormal distribution is equivalent 

to the lognormal distribution. 

The expected value and the variance of the delta portion of the modified delta-lognormal 

distribution can be calculated from the data as: 

k 

E$( X D ) = 

1 

$ � d

$ 

iDi (E-14)

d i= 1 

k 2 

V$ar( X D ) = 

1 

$ � d

$ 

i ( Di - E$ ( X D )) (E-15)

d i =1 

The parameters of the continuous portion of the modified delta-lognormal distribution, 

m$ and s$ 2 , are estimated by 

nc ln(xi ) m$ = � 

i=1 nc 

nc (ln(xi ) - m$ )

2 (E-16) 

s$ 2 = � 

i=1 nc -1 

where xi is the ith detected measurement value and nc is the number of detected measurements. Note 

that n = nd + nc. 

The expected value and the variance of the lognormal portion of the modified deltalognormal distribution can be calculated from the data as: 

E$ ( X C ) = exp �

� 

m$ + 

s$ 2 �

� (E-17)

Ł 2 ł 

E-6 
1

2

3

4

5

6

7

8

9

10

Appendix E - Modified Delta-Lognormal Distribution 

V$ar( X C ) = [ E$( XC )] 2 (exp(s$ 2 )-1) (E-18) 

Finally, the expected value and variance of the modified delta-lognormal distribution can 

be estimated using the following formulas: 

E$ (U ) = d

$ E$ ( X D ) + (1-d$

) E$ ( XC ) (E-19) 

V$ar(U ) = d

$ Ł

�

�

V$ar( X D ) +[ E$( X D )]

2 

ł

�

� + (1-d

$

)Ł

�

� V$ar( XC ) + [E$ ( XC )]

2 

ł

�

� -[E$ (U )]

2 

(E-20) 

Equations 17 through 20 are particularly important in the estimation of episode longterm averages and variability factors as described in the following sections. These sections are preceded 

by a section that identifies the episode data set requirements. 

Example: 

Consider a facility that has 10 samples with the following concentrations: 

Sample number Measurement Type Concentration (mg/L) 

ND 10 

ND 15 

ND 15 

ND 20 

NC 25 

NC 25 

NC 30 

NC 35 

NC 35 

NC 40 

The ND components of the variance equation are: 

D1 = 10, d$ 

1 = 1/10 

D2 = 15, d

$ 

2 = 1/5 

D3 = 20, d$ 

3 = 1/10. 

E-7
$ 

Appendix E - Modified Delta-Lognormal Distribution 

Since d

$ = 2/5, the expected value and the variance of the discrete portion of the modified deltalognormal distribution are 

1 � 1 1 1 � E

$ ( X D ) = 2 / 5 Ł

� 10 · 10 + 5 · 15 + 10 · 20ł� = 15, 

1 � 1 1 1 

V$

ar( X D ) = 2 / 5 Ł� 10 · (10 - 15)

2 + 5 · (15 - 15)2 + 10 · (20 - 15)2 �

ł

� = 12.5. 

The mean and variance of the log NC values are calculated as follows: nc

� ln( xi ) (2 · ln( 25) + ln(30) + 2 · ln(35) + ln( 40)) $ = 

i=1 = = 3.44 

n c 6

nc 2

� (ln( xi ) - m ) (2 · (ln( 25) - 3.44)

2 ) + (ln(30) - 3.44)2 

+ (2 · (ln( 35) - 3.44)

2 ) + (ln(40) - 3.44)2 

i =1 s$ = = = 0.0376 

nc - 1 5 

Then, the expected value and the variance of the lognormal portion of the modified delta-lognormal 

distribution are 

E$( X C ) = exp Ł�

� 

3.44 + 

0.0376 �

ł

� = 31.779 2 

V$ar( XC ) = [31.779] 2 (exp(0.0376) -1) = 38.695. 

The expected value and variance of the modified delta-lognormal distribution are 

E$ (U) = 

2

5 

· 15 + Ł

�

� 1- 2

5 

�

ł

� · 31.779 = 25.067 

V$ar(U ) = 

2 

· (12.5 + 152 ) + Ł

�

�

1- 2� ·(38.695+ 31.7792 ) - 25.0672 = 95.781. 5 5ł

� 

E-8

2 
Appendix E - Modified Delta-Lognormal Distribution 

E.4.1 Episode Data Set Requirements 

Estimates of the necessary parameters for the lognormal portion of the distribution can 

be calculated with as few as two distinct detected values in a data set. (In order to calculate the 

variance of the modified delta-lognormal distribution, two distinct detected values are the minimum 

number that can be used and still obtain an estimate of the variance for the distribution.) 

If an episode data set for a pollutant contained three or more observations with two or 

more distinct detected concentration values, then EPA used the modified delta-lognormal distribution to 

calculate long-term averages and variability factors. If the episode data set for a pollutant did not meet 

these requirements, EPA used an arithmetic average to calculate the episode long-term average and 

excluded the dataset from the variability factor calculations (because the variability could not be 

calculated). 

In statistical terms, each measurement was assumed to be independently and identically 

distributed from the other measurements of that pollutant in the episode data set. 

The next two sections apply the modified delta-lognormal distribution to the data for 

estimating episode long-term averages and variability factors for the MP&M industry. 

E.4.2 Estimation of Episode Long-Term Averages 

If an episode dataset for a pollutant meets the requirements described in the last section, 

then EPA calculated the long-term average using equation 19. Otherwise, EPA calculated the long-term 

average as the arithmetic average of the daily values where the sample-specific detection limit was used 

for each nondetected measurement. 

E.4.3 Estimation of Episode Daily Variability Factors 

For each episode, EPA estimated the daily variability factors by fitting a modified deltalognormal distribution to the daily measurements for each pollutant. The episode daily variability factor 

is a function of the expected value, and the 99th percentile of the modified delta-lognormal distribution fit 

to the daily concentration values of the pollutant in the wastewater from the episode. The expected 

value, was estimated using equation 19 (the expected value is the same as the episode long-term 

average). 

The 99th percentile of the modified delta-lognormal distribution fit to each data set was 

estimated by using an iterative approach. First, the pollutant-specific detection limits were ordered from 

smallest to largest. Next, the cumulative distribution function, p, for each detection limit was computed. 

The general form, for a given value c, was: 

E-9
o ß 

o ß 

Appendix E - Modified Delta-Lognormal Distribution 

p = � d

$ 

i + (1- d

$

)F

Œ

Ø

Œ 

ln(c 

s 

) 

$ 

- m$ 

œ

ø

œ (E-21) 

i:Di £c 

where M is the standard normal cumulative distribution function. Next, the interval containing the 99th 

percentile was identified. Finally, the 99th percentile of the modified delta-lognormal distribution was 

calculated. The following steps were completed to compute the estimated 99th percentile of each data 

subset: 

Step 1 Using equation 21, k values of p at c=Dm, m=1,...,k were computed and labeled pm. 

Step 2� The smallest value of m (m=1,...,k), such that pm $ 0.99, was determined and labeled as 

pj. If no such m existed, steps 3 and 4 were skipped and step 5 was computed instead. 

Step 3 Computed p* = pj - d

$ 

j . 

Step 4 If p* < 0.99, then P$ 99 = Dj 

else if p* > 0.99, then 

� Ø j -1 ø� � Œ0.99 -� d

$ 

i œ� 

P$ 99 = exp 

�

� m$ + s$ F-1 Œ

Œ i =1 œœ

�

� (E-22) 

� Œ 1 -d

$ œ� 

�

Ł o

Œ œ

ß

�

ł 

where M-1 is the inverse normal distribution function. 

Step 5 If no such m exists such that pm > 0.99 (m=1,...,k), then 

� P$ 99 = exp � m$ + s$ F -1 Ø

Œ 0.99 - d

$ 

œ

ø

�

� 

(E-23) �

Ł Œ 1 -d

$ œł

� 

The episode daily variability factor, VF1, was then calculated as: 

P$ 99 VF1 = 

E$(U ) (E-24) 

Example:�

Since no such m exists such that pm > 0.99 (m=1,...,k), �

E-10 
Appendix E - Modified Delta-Lognormal Distribution 

P$ 99 = exp Ł

�

� 

3.44 + 0.194 · F -1 Ø

Œ

0.99 - 0.4 ø

œ

�

� = 47.126. o 1 - 0.4 ßł 

The episode daily variability factor, VF1, was then calculated as: 

47.126

VF1 = = 1.880. 25.067 

To identify situations producing unexpected results, EPA reviewed all of the variability 

factors. EPA used several criteria to determine if the episode daily variability factors should be included 

in calculating the option variability factors. One criteria that EPA used was that the daily variability 

factors should be greater than 1.0. A variability factor less than 1.0 would result in a unexpected result 

where the estimated 99th percentile would be less than the long-term average. This would be an 

indication that the estimate of s$ (the log standard deviation) was unstable. A second criteria was that 

not all of the sample-specific detection limits could exceed the values of the noncensored values. All the 

episode variability factors used for the limitations and standards met these criteria. 

References 

1.� Aitchison, J. and J.A.C. Brown. 1963. The Lognormal Distribution. Cambridge 

University Press, New York. 

2.� Barakat, R. 1976. “Sums of Independent Lognormally Distributed Random Variables.” 

Journal of the Optical Society of America, 66: 211-216. 

3.� Cohen, A. Clifford. 1976. Progressively Censored Sampling in the Three Parameter 

Log-Normal Distribution. Technometrics, 18:99-103. 

4.� Crow, E.L. and K. Shimizu. 1988. Lognormal Distributions: Theory and 

Applications. Marcel Dekker, Inc., New York. 

5.� Kahn, H.D., and M.B. Rubin. 1989. "Use of Statistical Methods in Industrial Water 

Pollution Control Regulations in the United States." Environmental Monitoring and 

Assessment. Vol. 12:129-148. 

6.� Owen, W.J. and T.A. DeRouen. 1980. Estimation of the Mean for Lognormal Data 

Containing Zeroes and Left-Censored Values, with Applications to the Measurement of 

Worker Exposure to Air Contaminants. Biometrics, 36:707-719. 

E-11

E.5 
Appendix E - Modified Delta-Lognormal Distribution 

7. U.S. Environmental Protection Agency. 2000. Development Document for Effluent 

Limitations Guidelines and Standards for the Centralized Waste Treatment Point Source 

Category. Volume I, Volume II. EPA 440/1-87/009. 

8.� U.S. Environmental Protection Agency. 2002. Development Document for Effluent 

Limitations Guidelines and Standards for the Iron and Steel Manufacturing Point Source 

Category. EPA-821-R-02-004. 

E-12