Technical Development Document for

Proposed Effluent Limitation

Guidelines and Standards for 

the Airport Deicing Category

July 2009
Technical Development Document 

for Proposed Effluent Limitation Guidelines and Standards for the 

Airport Deicing Category 

Engineering and Analysis Division 

Office of Water / Office of Science and Technology 

U.S. Environmental Protection Agency 

Washington, D.C. 20460 

July 2009 

EPA 821-R-09-004 
Technical Development Document for Proposed Effluent 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 i 

ACKNOWLEDGMENTS AND DISCLAIMER 

This document was prepared by Environmental Protection Agency Office of Water staff. The 

following contractors provided assistance in performing the analyses supporting the conclusions 

detailed in this document. 

Eastern Research Group, Inc. 

Office of Water staff have reviewed and approved this document for publication. Neither the 

United States Government nor any of its employees, contractors, subcontractors, or their 

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 document, or represents that its use by such a party would 

not infringe on privately owned rights. 
Technical Development Document for Proposed Effluent 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 ii

CONTENTS 

Page 

1. LEGAL AUTHORITY...........................................................................................................1-1 

1.1 Clean Water Act (CWA)......................................................................................1-1 

1.1.1 Best Practicable Control Technology Currently Available (BPT) ..........1-1 

1.1.2 Best Conventional Pollutant Control Technology (BCT)........................1-1 

1.1.3 Best Available Technology Economically Achievable (BAT)................1-1 

1.1.4 New Source Performance Standards (NSPS) ..........................................1-2 

1.1.5 Pretreatment Standards for Existing Sources (PSES)..............................1-2 

1.1.6 Pretreatment Standards for New Sources (PSNS) ...................................1-2 

1.2 Effluent Guidelines Plan Requirements...............................................................1-3 

2. APPLICABILITY AND SUBCATEGORIZATION ......................................................................2-1 

2.1 Applicability of the Regulation............................................................................2-1 

2.2 Subcategorization.................................................................................................2-1 

2.2.1 ADF Usage...............................................................................................2-1 

2.2.2 FAA Classification...................................................................................2-2 

2.2.3 Airport Departures ...................................................................................2-2 

2.2.4 Land Availability .....................................................................................2-2 

2.2.5 Conclusions..............................................................................................2-2 

3. SUMMARY AND SCOPE OF REGULATION ...........................................................................3-1 

3.1 Summary of Rule .................................................................................................3-1 

3.1.1 Best Available Technology Economically Achievable (BAT)................3-1 

3.1.2 New Source Performance Standards (NSPS) ..........................................3-1 

3.1.3 Pretreatment Standards for Existing Sources (PSES)..............................3-1 

3.1.4 Pretreatment Standards for New Sources (PSNS) ...................................3-2 

4. DATA COLLECTION ACTIVITIES ........................................................................................4-1 

4.1 Preliminary Data Summary..................................................................................4-1 

4.2 Site Visits.............................................................................................................4-2

4.3 Industry Questionnaires (Surveys).......................................................................4-5 

4.3.1 Recipient Selection and Questionnaire Distribution................................4-5 

4.3.2 Questionnaire Information Collected.......................................................4-6 

4.3.3 Questionnaire Technical Review, Coding, and Data Entry .....................4-9 

4.4 Field Sampling...................................................................................................4-10 

4.5 Permit Review....................................................................................................4-10 

4.5.1 Airport Selection for Permit Review .....................................................4-12 

4.5.2 Obtaining NPDES Permits.....................................................................4-12 

4.5.3 Permit Review Process ..........................................................................4-12 

4.6 Industry-Submitted Data....................................................................................4-16 

4.7 Literature Reviews.............................................................................................4-17 

4.7.1 Current Deicing Practices and Treatment Technologies .......................4-18 

4.7.2 Current Airport Deicing Runoff Data....................................................4-19 

4.7.3 Chemical Information and Environmental Impact Studies....................4-19 

4.7.4 Current Deicing Runoff Regulations .....................................................4-19 

4.8 References..........................................................................................................4-20 
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July 2009 iii

5. OVERVIEW OF THE INDUSTRY ...........................................................................................5-1 

5.1 Industry Statistics.................................................................................................5-1 

5.1.1 Airports ....................................................................................................5-1 

5.1.2 Airlines.....................................................................................................5-5 

5.2 Industry Practices.................................................................................................5-7 

5.2.1 Airfield Deicing Practices........................................................................5-7 

5.2.2 Aircraft Deicing Practices........................................................................5-9 

5.2.3 Airport Deicing Stormwater Collection and Control.............................5-13 

5.3 References..........................................................................................................5-14 

6. DEICING CHEMICAL USE AND DEICING STORMWATER CHARACTERIZATION....................6-1 

6.1 Deicing Chemical Usage......................................................................................6-1 

6.1.1 Airfield Chemical Use .............................................................................6-1 

6.1.2 Aircraft Chemical Use and Purchasing Patterns......................................6-2 

6.2 Deicing Stormwater Characterization..................................................................6-3 

6.2.1 Airfield Deicing Chemicals and Associated Deicing Stormwater...........6-3 

6.2.2 Aircraft Deicing Chemicals and Associated Deicing Stormwater...........6-4 

6.3 References..........................................................................................................6-13 

7. POLLUTANTS OF CONCERN ...............................................................................................7-1 

7.1 Identification of Airport Deicing/Anti-icing Stormwater Pollutants...................7-1 

7.2 Pollutants of Concern Selection Criteria..............................................................7-8 

7.3 Identification of Potential Pollutants of Concern.................................................7-9 

7.4 Selection of Regulated Pollutants for Proposal .................................................7-10 

7.5 References..........................................................................................................7-13 

8. POLLUTION PREVENTION AND TREATMENT TECHNOLOGIES APPLICABLE TO AIRPORT 

DEICING OPERATIONS.......................................................................................................8-1 

8.1 Deicing Stormwater Collection............................................................................8-1 

8.1.1 Deicing Stormwater Collection and Conveyance....................................8-1 

8.1.2 Deicing Stormwater Storage....................................................................8-5 

8.2 Treatment and Recycling .....................................................................................8-7 

8.2.1 Oil/Water Separators and DAF................................................................8-8 

8.2.2 Biological Treatment ...............................................................................8-8 

8.2.3 Membrane Separation ............................................................................8-12 

8.2.4 Filtration.................................................................................................8-13 

8.2.5 Mechanical Vapor Recompression ........................................................8-13 

8.2.6 Distillation..............................................................................................8-13 

8.3 Pollution Prevention and Product Substitution Practices...................................8-14 

8.3.1 Infrared Deicing.....................................................................................8-14 

8.3.2 Forced Air Deicing ................................................................................8-16 

8.3.3 Aircraft Deicing/Anti-Icing Product Substitution Practices ..................8-16 

8.3.4 Airfield Deicing Product Substitution Practices....................................8-17 

8.3.5 Best Management Practices (BMPs) .....................................................8-17 

8.4 References..........................................................................................................8-20 
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CONTENTS (Continued) 

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July 2009 iv

9. CONTROL AND TREATMENT PERFORMANCE .....................................................................9-1 

9.1 Development of Proposed Control and Treatment Scenarios..............................9-1 

9.1.1 GRVs........................................................................................................9-1 

9.1.2 GRVs in Combination with Plug and Pump Systems..............................9-2 

9.1.3 Deicing Pads ............................................................................................9-2 

9.1.4 AFB Biological Treatment.......................................................................9-2 

9.1.5 Recycle/Recovery Operations..................................................................9-3 

9.2 Performance of Control and Treatment Scenarios...............................................9-3 

9.2.1 GRV Collection (20 Percent Efficiency Scenario) ..................................9-4 

9.2.2 Plug and pump Collection (40 Percent Efficiency Scenario) ..................9-4 

9.2.3 Deicing Pad Collection (60 Percent Efficiency Scenario).......................9-4 

9.2.4 AFB Treatment Performance...................................................................9-5 

9.3 References............................................................................................................9-5 

10. POLLUTANT LOADINGS AND POLLUTANT LOAD REDUCTION ESTIMATES.......................10-1 

10.1 Data Sources ......................................................................................................10-1 

10.2 Pollutant Loadings Methodology Overview......................................................10-2 

10.3 Step 1: Estimate the Amount of Applied ADF and Pavement Deicing 

Chemicals...........................................................................................................10-2 

10.3.1 Pavement Deicing and Pavement Anti-Icing Chemical Usage Estimate10-3 

10.3.2 ADF Usage Estimate..............................................................................10-8 

10.4 Step 2: Calculate the Amount of Pollutant Load Associated with the Applied 

Chemicals.........................................................................................................10-12 

10.4.1 Calculate the Total Mass of Each Pollutant.........................................10-18 

10.4.2 Determine the Theoretical Oxygen Demand of Each Chemical..........10-18 

10.4.3 Determine the COD of Each Chemical................................................10-18 

10.4.4 Determine the BOD5 of Each Chemical ..............................................10-19 

10.5 Step 3: Estimate the Amount of Baseline Pollutant Load that is Discharged 

Directly ............................................................................................................10-19 

10.5.1 Direct Discharge of Pavement Deicers................................................10-19 

10.5.2 Direct Discharge of ADF.....................................................................10-19 

10.6 Step 4: Estimate Pollutant Loading Removals for Each EPA 

Collection/Control Scenario.............................................................................10-20 

10.7 Approach for Calculating Urea-Related Reductions .......................................10-26 

10.8 References........................................................................................................10-28 

11. TECHNOLOGY COSTS ......................................................................................................11-1 

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

11.2 Development of Cost Model Inputs...................................................................11-8 

11.2.1 Model Site Development .......................................................................11-8 

11.2.2 Airport Operations Data.........................................................................11-9 

11.2.3 Precipitation Data and Site Characteristics............................................11-9 

11.3 General Methodology for Estimating Collection and Treatment Technology 

Costs.................................................................................................................11-11 
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CONTENTS (Continued) 

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11.3.1 Overview of the ADF Collection and Treatment Cost Model.............11-11 

11.3.2 Cost Model Equation Development.....................................................11-13 

11.3.3 Cost Model Design ..............................................................................11-29 

11.3.4 Annualized Costs for ADF Collection and Treatment Alternatives ....11-38 

11.4 Airfield Deicing Costs .....................................................................................11-39 

11.4.1 Urea and Potassium Acetate Chemical Costs and Application Rates..11-39 

11.4.2 Cost Impact of Discontinuing Urea Airfield Deicing..........................11-40 

11.4.3 Urea Monitoring Costs.........................................................................11-40 

11.5 References........................................................................................................11-44 

12. NON-WATER QUALITY IMPACTS ....................................................................................12-1 

12.1 Energy Requirements.........................................................................................12-1 

12.2 Air Emissions.....................................................................................................12-3 

12.3 Solid Waste Generation .....................................................................................12-9 

12.4 References..........................................................................................................12-9 

13. REGULATORY OPTION SELECTION ..................................................................................13-1 

13.1 Regulatory Options Evaluated ...........................................................................13-1 

13.2 Option Selection.................................................................................................13-4 

13.2.1 BAT........................................................................................................13-5 

13.2.2 PSES/PSNS............................................................................................13-6 

13.2.3 NSPS......................................................................................................13-7 

13.3 References..........................................................................................................13-8 

14. LIMITATIONS AND STANDARDS: DATA SELECTION AND CALCULATION .........................14-1 

14.1 Selected Pollutant Parameters............................................................................14-1 

14.1.1 Chemical Oxygen Demand (COD)........................................................14-1 

14.1.2 Ammonia as Nitrogen (Ammonia) ........................................................14-1 

14.2 Overview of Data Review and Selection...........................................................14-2 

14.2.1 Data Selection Criteria...........................................................................14-2 

14.2.2 Other Considerations in Data Selection.................................................14-4 

14.2.3 Importance of Comments for Data Evaluations for Final Limitations ..14-5 

14.3 Conventions for Modeling Multiple Data Sets from the Same Facility ............14-6 

14.4 COD: Data Selected as Basis of Proposed Limitations .....................................14-6 

14.4.1 Albany Treatment System......................................................................14-7 

14.5 Ammonia: Data Selected as Basis of Proposed Limitation .............................14-11 

14.6 Limitations: Basis and Calculations.................................................................14-12 

14.6.1 Definitions............................................................................................14-13 

14.6.2 Percentile Basis of the Limitations ......................................................14-13 

14.6.3 Estimation Procedures for Percentiles .................................................14-14 

14.7 Achievability of Limitations............................................................................14-18 

14.7.1 Statistical and Engineering Review of Limitations .............................14-18 

14.7.2 Compliance with Limitations...............................................................14-21 

14.8 References........................................................................................................14-23 
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Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 vi

LIST OF TABLES 

Page 

3-1 BAT Limitations .............................................................................................................. 3-1 

3-2 New Source Performance Standards................................................................................ 3-1 

3-3 Summary of Proposed Airport Deicing Effluent Limitation Guidelines and 

Standards.......................................................................................................................... 3-2 

4-1 Airports Visited and Reasons for Site Visits ................................................................... 4-3 

4-2 Deicing Questionnaire Response Rates ........................................................................... 4-5 

4-3 Airports Selected for Sampling and the Reason for Their Selection............................. 4-11 

4-4 Top 50 Airports in the United States with the Highest ADF Usage, Estimated 

Based on Snow and Freezing Precipitation Days and Total Airport Departures........... 4-13 

4-5 Permit Review General Information Table.................................................................... 4-15 

4-6 Permit Review Pollutant-Specific Information Table.................................................... 4-16 

4-7 Summary of Costing Data Provided by Industry........................................................... 4-17 

4-8 Summary of Long-Term Analytical Data Provided by Industry ................................... 4-17 

5-1 Number of U.S. Airports by Airport Type in 2004.......................................................... 5-2 

5-2 Deicing Airports by FAA Region for the Three Winter Seasons .................................... 5-3 

5-3 Airline Classifications...................................................................................................... 5-6 

5-4 National Estimate of Airports Using Deicing Chemicals or Materials............................ 5-8 

5-5 Summary of Airfield Pollution Prevention Practices....................................................... 5-9 

5-6 Deicing/Anti-Icing Chemicals Purchased by Airlines that Deiced Their Own 

Aircraft........................................................................................................................... 5-11 

5-7 Deicing/Anti-Icing Chemicals Purchased for Aircraft Deiced by an FBO.................... 5-11 

5-8 Summary of Mechanical and Nonchemical Aircraft Deicing Methods Used by an 

Airline ............................................................................................................................ 5-12 

5-9 Summary of Mechanical and Nonchemical Aircraft Deicing Methods Used By 

FBOs .............................................................................................................................. 5-12 
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Limitation Guidelines and Standards for the Airport Deicing Category 

LIST OF TABLES (Continued) 

Page 

July 2009 vii

5-10 Summary of Aircraft Pollution Prevention Practices..................................................... 5-13 

5-11 Summary of Airport Collection, Containment, and Conveyance Methods................... 5-14 

6-1 Surveyed U.S. Commercial Airports - Airfield Chemical Usage.................................... 6-2 

6-2 U.S. Commercial Airports - National Estimate of Airfield Chemical Usage.................. 6-2 

6-3 U.S. Commercial Airports – National Estimate of Aircraft Chemical 

Usage/Purchase................................................................................................................ 6-3 

6-4 EPA’s Analytical Results for Pond 3E Effluent and Pond 6 Effluent, DTW.................. 6-5 

6-5 MSP and DTW Grab Sample Data Summary for Collected Deicing Stormwater .......... 6-7 

6-6 DEN, PIT, and ALB - 5-Day Average Data Summary for Untreated Deicing 

Stormwater....................................................................................................................... 6-9 

6-7 RFD - 1-Day Data Summary for Untreated Deicing Stormwater.................................. 6-12 

7-1 Pollutants Under Consideration as Potential Pollutants of Concern................................ 7-3 

7-2 Potential Pollutants of Concern Selected for Proposed Regulation............................... 7-12 

8-1 ADF Alternatives........................................................................................................... 8-16 

10-1 Three-Year Average Amount of Pavement Deicing Chemical Usage, in Pounds ........ 10-4 

10-2 ADF Estimates Based on Airline Detailed Questionnaire Responses........................... 10-9 

10-3 ADF Data Reported in the Airport Questionnaire ....................................................... 10-11 

10-4 ADF Annual Usage Estimates for All Airports that Received the Airport 

Questionnaire ............................................................................................................... 10-13 

10-5 Theoretical Oxygen Demand Calculations for Deicing Chemicals............................. 10-18 

10-6 ADF COD Baseline Loads and Loading Reductions for Each Control and 

Treatment Scenario, by Airport ................................................................................... 10-21 

10-7 Baseline COD Load and Potential Load Reduction Associated with the 

Discontinued Use of Urea as an Airfield Deicing Chemical ....................................... 10-27 

11-1 Annualized Costs by Surveyed Airport for Each Collection and Control Scenario 

Evaluated by EPA ......................................................................................................... 11-3 
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Limitation Guidelines and Standards for the Airport Deicing Category 

LIST OF TABLES (Continued) 

Page 

July 2009 viii

11-2 Airport Questionnaire Data to Estimate Spent ADF Collection and Treatment 

Costs............................................................................................................................. 11-10 

11-3 Reported Costs for GRVs and Outfall-Normalized Capital and Annual Costs........... 11-15 

11-4 Normalized Capital and Operating Costs for the Plug-and-Pump Collection 

System.......................................................................................................................... 11-16 

11-5 Normalized Installed Capital Costs for Centralized Deicing Pads .............................. 11-17 

11-6 Flow-Normalized Installed Capital Costs for the UF/RO ADF Treatment System .... 11-20 

11-7 Expected ADF Percentage Collected and ADF Concentration in Collected 

Stormwater................................................................................................................... 11-20 

11-8 Flow-Normalized Annual O&M Costs for the UF/RO Recycle and Recovery 

System.......................................................................................................................... 11-21 

11-9 Flow-Normalized Installed Capital Costs for the MVR/Distillation ADF 

Treatment System ........................................................................................................ 11-22 

11-10 Load-Normalized Installed Capital Costs for the Anaerobic Fluid Bed Reactors....... 11-23 

11-11 Load Normalized Annual O&M Costs for the Anaerobic Fluid Bed Reactors ........... 11-23 

11-12 Installed Capital Costs for Various Retention Ponds................................................... 11-25 

11-13 Estimated Cost for 1,000 Linear Feet of Stormwater Piping....................................... 11-27 

11-14 Storage Tank Volumes and Installed Capital Cost for Various Airports..................... 11-28 

11-15 Airport Deicing Cost Model Equations, Input Variables and Assumptions................ 11-32 

11-16 Average Cost for Urea and Potassium Acetate, 2002-2005 ........................................ 11-39 

11-17 Typical Application Rates for Potassium Acetate ....................................................... 11-39 

11-18 Application Rates for Sodium Acetate and Urea......................................................... 11-40 

11-19 Cost for Application of Urea and Potassium Acetate, per 1000 Square Feet.............. 11-40 

11-20 Incremental Costs for Airports to Change from Urea to Potassium Acetate for 

Airfield Deicing ........................................................................................................... 11-42 

11-21 Estimated Annual Costs for Airports to Conduct Effluent Monitoring Program For 

Urea Airfield Deicing .................................................................................................. 11-43 
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Limitation Guidelines and Standards for the Airport Deicing Category 

LIST OF TABLES (Continued) 

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July 2009 ix

12-1 Estimated Electrical Requirements for All AFB Treatment Systems............................ 12-2 

12-2 Potential Electricity Generation from AFB Biogas Generation .................................... 12-2 

12-3 Estimated Incremental Criteria Pollutant Emissions from GRVs.................................. 12-4 

12-4 BTS to EDMS Matching Based on Aircraft .................................................................. 12-5 

12-5 BTS to EDMS Matching Based on LTOs ..................................................................... 12-5 

12-6 Incremental Criteria Pollutant Emissions Associated with Aircraft Deicing 

Operations...................................................................................................................... 12-7 

12-7 Comparison of Total Annual LTO Aircraft Emissions to Emissions Resulting in 

Deicing Operations ........................................................................................................ 12-8 

12-8 Potential Air Emissions from AFB Treatment Systems ................................................ 12-8 

12-9 Estimated Sludge Generation from AFB Bioreactors Treating ADF Contaminated 

Stormwater..................................................................................................................... 12-9 

13-1 Regulatory Options Evaluated for the Airport Deicing Category ................................. 13-3 

13-2 Factors Evaluated by EPA in Option Selection ............................................................. 13-5 

13-3 Urea Replacement Load Removals and Costs............................................................... 13-5 

14-1 COD: EPA and Airport Self-Monitoring Effluent Data Collected During EPA’s 

Sampling Episode .......................................................................................................... 14-8 

14-2 COD: Dates Excluded Because Units Operated in Series ............................................. 14-9 

14-3 COD: Dates Excluded Because Influent Concentration Reported as Zero.................. 14-10 

14-4 COD: Dates Excluded Because of Performance Excursions....................................... 14-10 

14-5 COD: Summary of Albany Self-Monitoring Effluent Data After Exclusions............. 14-11 

14-6 Ammonia: Data from Albany Airport Used to Develop Limitations .......................... 14-12 

14-7 COD and Ammonia: Proposed Limitations with Long-Term Averages and 

Variability Factors ....................................................................................................... 14-15

14-8 COD: 99th Percentile Estimates from Each Treatment Unit ........................................ 14-15 

14-9 COD: Effect of Number of Daily Values in Weekly Averages................................... 14-16 
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LIST OF TABLES (Continued) 

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July 2009 x

14-10 Ammonia: Consideration of Autocorrelation for Proposed Limitations, LongTerm Averages, and Variability Factors...................................................................... 14-18 

14-11 COD: Dates and Values Greater than Proposed Limitation of 271 mg/L ................... 14-20 

14-12 COD: Summary Statistics of Influent Concentrations................................................. 14-21 
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July 2009 xi

LIST OF FIGURES 

Page 

5-1 Percentage of Airports Deicing Airfield Pavement Each Month..................................... 5-4 

5-2 Discharge Status of Airports............................................................................................ 5-5

8-1 Deicing Pad Equipped with Fixed Deicing Booms at Pittsburgh Airport ....................... 8-2 

8-2 Mobile Deicer Truck Performing Gate Deicing at Chicago O’Hare Airport .................. 8-3 

8-3 Glycol Recovery Vehicle................................................................................................. 8-5 

8-4 Pond for Deicing Stormwater Storage at Denver International Airport .......................... 8-6 

8-5 Frac Tanks........................................................................................................................ 8-7 

8-6 Aerated Pond Installation at Portland Airport ............................................................... 8-10 

8-7 Typical Anaerobic Fluid Bed Treatment System for Treatment of Stormwater 

Contaminated by ADF ................................................................................................... 8-11 

8-8 Engineered Wetlands Installation at Buffalo Niagara Airport....................................... 8-12 

8-9 Infrared Hangar at JFK Airport...................................................................................... 8-15 

10-1 ADF Factor vs. PG/EG Gallons for U.S. Airports (excluding Alaska) ....................... 10-11 

10-2 ADF Factor vs. PG/EG Gallons for Alaskan Airports................................................. 10-12 

11-1 Diagram Showing the Steps for Developing Collection System Costs by the 

Airport Deicing Cost Model ........................................................................................ 11-30 

11-2 Diagram Showing the Alternatives for Developing Treatment System Costs by the 

Airport Deicing Cost Model ........................................................................................ 11-31 

12-1 Landing and Take Off Cycle.......................................................................................... 12-6 

14-1 Simplified Drawing of Albany Treatment System and Sample Points.......................... 14-8 
Technical Development Document for Proposed Effluent 1. Legal Authority 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 1-1 

1. LEGAL AUTHORITY

 Effluent limitation guidelines and standards for the Airport Deicing Category would be 

promulgated under the authority of Sections 301, 304, 306, 307, 308, and 501 of the Clean Water 

Act, 33 U.S.C. 1311, 1314, 1316, 1317, 1318, and 1361. 

1.1 Clean Water Act (CWA)

 Congress passed the Federal Water Pollution Control Act Amendments of 1972, also 

known as the Clean Water Act (CWA), to “restore and maintain the chemical, physical, and 

biological integrity of the Nation’s waters” (Section 101(a)). To implement the Act, the United 

States Environmental Protection Agency (EPA) is to issue effluent limitation guidelines, 

pretreatment standards, and new source performance standards for industrial dischargers. These 

guidelines and standards are summarized briefly in the following sections. 

1.1.1 Best Practicable Control Technology Currently Available (BPT) 

 Traditionally, EPA establishes BPT effluent limitations based on the average of the best 

performances of facilities within the industry, grouped to reflect various ages, sizes, processes, or 

other common characteristics. EPA may promulgate BPT effluent limits for conventional, toxic, 

and non-conventional pollutants. In specifying BPT, EPA looks at a number of factors. EPA first 

considers the cost of achieving effluent reductions in relation to the effluent reduction benefits. 

The Agency also considers the age of the equipment and facilities, the processes employed, 

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

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

Administrator deems appropriate. See CWA sec. 304(b)(1)(B)). If, however, existing 

performance is uniformly inadequate, EPA may establish limitations based on higher levels of 

control than currently in place in an industrial category when based on an Agency determination 

that the technology is available in another category or subcategory, and can be practically 

applied. 

1.1.2 Best Conventional Pollutant Control Technology (BCT) 

 The 1977 amendments to the CWA required EPA to identify additional levels of effluent 

reduction for conventional pollutants associated with BCT technology for discharges from 

existing industrial point sources. In addition to other factors specified in section 304(b)(4)(B), 

the CWA requires that EPA establish BCT limitations after consideration of a two part “costreasonableness” test. EPA explained its methodology for the development of BCT limitations in 

July 1986 (51 FR 24974). Section 304(a)(4) designates the following as conventional pollutants: 

biochemical oxygen demand over 5 days (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; 40 CFR 401.16). 

1.1.3 Best Available Technology Economically Achievable (BAT) 

 BAT represents the second level of stringency for controlling direct discharge of toxic 

and nonconventional pollutants. In general, BAT effluent limitation guidelines represent the best 

economically achievable performance of facilities in the industrial subcategory or category. The 
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Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 1-2 

factors considered in assessing BAT include the cost of achieving BAT effluent reductions, the 

age of equipment and facilities involved, the process employed, potential process changes, and 

non-water quality environmental impacts including energy requirements, and such other factors 

as the Administrator deems appropriate. The Agency retains considerable discretion in assigning 

the weight to be accorded these factors. An additional statutory factor considered in setting BAT 

is economic achievability. Generally, EPA determines economic achievability based on total 

costs to the industry and the effect of compliance with BAT limitations on overall industry and 

subcategory financial conditions. As with BPT, where existing performance is uniformly 

inadequate, BAT may reflect a higher level of performance than is currently being achieved 

based on technology transferred from a different subcategory or category. BAT may be based 

upon process changes or internal controls, even when these technologies are not common 

industry practice. 

1.1.4 New Source Performance Standards (NSPS) 

 NSPS reflect effluent reductions that are achievable based on the best available 

demonstrated control 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 most stringent controls attainable through the application of the best available 

demonstrated control technology for all pollutants (that is, conventional, nonconventional, and 

priority pollutants). In establishing NSPS, EPA is directed to take into consideration the cost of 

achieving the effluent reduction and any non-water quality environmental impacts and energy 

requirements. 

1.1.5 Pretreatment Standards for Existing Sources (PSES) 

Pretreatment standards apply to discharges of pollutants to publicly owned treatment 

works (POTWs) rather than to discharges to waters of the United States. PSES are designed to 

prevent the discharge of pollutants that pass through, interfere with, or are otherwise 

incompatible with the operation of POTWs. Categorical pretreatment standards are technologybased and analogous to BAT effluent limitation guidelines. The General Pretreatment 

Regulations, which set forth the framework for the implementation of categorical pretreatment 

standards, are found at 40 CFR Part 403. These regulations establish pretreatment standards that 

apply to all non-domestic dischargers. See 52 FR 1586 (January 14, 1987). 

1.1.6 Pretreatment Standards for New Sources (PSNS) 

Section 307(c) of the Act calls for EPA to promulgate PSNS at the same time it 

promulgates NSPS. Such pretreatment standards must prevent the discharge of any pollutant into 

a POTW that may interfere with, pass through, or may otherwise be incompatible with the 

POTW. EPA promulgates categorical PSES based principally on BAT technology for existing 

sources. EPA promulgates PSNS based on best available demonstrated technology for new 

sources. New indirect discharges have the opportunity to incorporate into their facilities the best 

available demonstrated technologies. The Agency considers the same factors in promulgating 

PSNS as it considers in promulgating NSPS. 
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July 2009 1-3 

1.2 Effluent Guidelines Plan 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 limitation guidelines and 

standards (“effluent guidelines”) and (2) promulgating new effluent guidelines. On September 2, 

2004, EPA published an Effluent Guidelines Plan (69 FR 53705) that established schedules for 

developing new and revised effluent guidelines for several industry categories. One of the 

industries for which the Agency established a schedule was the Airport Deicing Category. 
Technical Development Document for Proposed Effluent 2. Applicability and Subcategorization 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 2-1 

2. APPLICABILITY AND SUBCATEGORIZATION

 The proposed regulations for the Airport Deicing Category include effluent limitation 

guidelines and standards for the control of pollutants in wastewater. This document presents the 

information and rationale supporting the proposed effluent limitation guidelines and standards. 

Section 2.0 highlights the applicability and subcategorization basis of this proposed regulation. 

2.1 Applicability of the Regulation

 Airports in the scope of this proposed regulation are defined as Primary Commercial 

Airports with greater than 1,000 annual jet departures. The wastewater flows covered by the 

proposed rule include all stormwater contaminated with spent aircraft deicing fluid (ADF) as 

well as stormwater contaminated with airfield deicing chemicals. EPA has estimated that 218 

airports would be covered by this proposed regulation. 

2.2 Subcategorization

 EPA may divide a point source category into groupings called "subcategories" to provide 

a method for addressing variations between products, processes, and other factors, which result 

in distinctly different effluent characteristics. EPA used published literature, site visit interviews 

and data, industry questionnaire responses, and EPA sampling data for the subcategorization 

analysis. Various subcategorization criteria were analyzed for trends in discharge flow rates, 

pollutant concentrations, and treatability to determine if/where subcategorization was warranted. 

EPA analyzed several factors to determine whether subcategorizing an industrial category and 

considering different technology options for those subcategories would be appropriate. For this 

analysis, EPA evaluated the characteristics of the industrial category to determine their potential 

to provide the Agency with a means to differentiate effluent quantity and quality among 

facilities. EPA also evaluated the design, process, and operational characteristics of the different 

industry segments to determine technology control options that might be applied to reduce 

effluent quantity and improve effluent quality. The factors associated with the Airport Deicing 

category are as follows: 

• ADF usage; 

• Federal Aviation Administration (FAA) classifications; 

• Airport departures; and 

• Land availability. 

2.2.1 ADF Usage 

 Ethylene and propylene glycols are the main ingredients in aircraft deicing fluid. Through 

EPA’s research, it became apparent that the volume of glycol required to deice a single aircraft 

varied greatly depending on a plethora of variables including weather conditions, aircraft size 

and operator training. EPA reviewed industry questionnaire responses and determined that ADF 

usage is the best indicator for the volume of deicing operations that occur at an airport. ADF 

usage can range from zero to hundreds of thousands of gallons per year at airports across the 

United States. 
Technical Development Document for Proposed Effluent 2. Applicability and Subcategorization 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 2-2 

2.2.2 FAA Classification 

 The Airport and Airway Improvement Act (AAIA) and the FAA classify airports by size 

based on the volume of commercial traffic. (Non-commercial airports, commonly known as 

"General Aviation" airports, are not specifically defined by the AAIA.) EPA utilized this 

classification system to organize its data collection and analysis of the aviation industry. The 

AAIA defines airports by categories of airport activities, including Commercial Service (Primary 

and Non-Primary), Cargo Service, and Reliever. Commercial Service Airports are publicly 

owned airports that have at least 2,500 passenger boardings each calendar year and received 

scheduled passenger service. The definition also includes passengers who continue on an aircraft 

in international flight that stops at an airport in any of the 50 states for a non-traffic purpose, 

such as refueling or aircraft maintenance rather than passenger activity. Primary Commercial 

Service airports have more than 10,000 passenger boardings each year. Primary airports are 

further subdivided into Large Hub, Medium Hub, Small Hub and Non-Hub classifications, based 

on the percentage of total passenger boardings within the U.S. in the most current calendar year 

ending before the start of the current fiscal year. 

 Early on in the regulatory process, EPA made the assumption that the majority of the 

deicing in the U.S. would occur at Primary Commercial airports and particularly those with jet 

departures. General aviation aircraft, as well as smaller commercial non-jet aircraft are expected 

to suspend flights during inclement weather, whereas commercial aircraft with scheduled service 

are much more likely to deice in order to meet customer demands. 

2.2.3 Airport Departures 

 While ADF usage and FAA classification are important criteria for determining where 

most of the aircraft deicing would occur, EPA considered an additional criterion in order to 

reflect the economic achievability of potential regulatory requirements Within the Primary 

Commercial airport stratum, the size of an airport, based on departures, was used by EPA to 

classify affordability of this proposed regulation with respect to a specific airport. This size 

threshold includes a minimum number of annual jet departures as well as the minimum number 

of total annual departures. 

2.2.4 Land Availability 

 EPA is aware that airports across the country have different amounts of land that may be 

available for facility modifications, such as for installation of environmental controls. EPA 

collected some basic information from airports on their current configurations. However, neither 

the aviation industry nor the FAA has developed a standard definition of land availability, and 

EPA did not formulate a definition but has requested public comment on this topic in the 

proposed rule. 

2.2.5 Conclusions 

 Establishing formal subcategories is not necessary for the Airport Deicing category 

because the proposed rule is structured to address the relevant factors (i.e., amount of ADF 

applied and number of departures) and establish a set of requirements that encompasses the range 

of situations that an airport may encounter during deicing operations. Both the aircraft deicing 

and pavement deicing requirements use airport size thresholds, which exclude smaller facilities. 
Technical Development Document for Proposed Effluent 2. Applicability and Subcategorization 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 2-3 

The use of a performance standard, as compared to a technology specification, provides 

flexibility for airports in meeting the requirements. 
Technical Development Document for Proposed Effluent 3. Summary and Scope of Regulation 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 3-1 

3. SUMMARY AND SCOPE OF REGULATION

3.1 Summary of Rule

 The components of the proposed rules to the Airport Deicing Category are described in 

the following subsections. 

3.1.1 Best Available Technology Economically Achievable (BAT) 

 EPA is proposing BAT for the Airport Deicing Category to control priority and 

nonconventional pollutants in deicing stormwaters from direct dischargers through the regulation 

of Chemical Oxygen Demand (COD) and ammonia as nitrogen. Table 3-1 presents the BAT 

Limitations proposed. 

Table 3-1. BAT Limitations 

Wastestream 

Pollutant or Pollutant 

Property Daily Maximum Weekly Average 

Aircraft Deicing COD 271 mg/L 154 mg/L 

Airfield Pavement Deicing Ammonia as Nitrogen 14.7 mg/L 

Table 3-3 presents the technology basis for the effluent limitation guidelines. 

3.1.2 New Source Performance Standards (NSPS) 

 EPA is proposing NSPS for the Airport Deicing Category to control priority, 

nonconventional, and conventional pollutants in wastewater from new direct dischargers through 

the regulation of COD and ammonia as nitrogen. Table 3-2 presents the NSPS proposed. 

Table 3-2. New Source Performance Standards 

Wastestream Pollutant or Pollutant Property Daily Maximum Weekly Average 

Aircraft Deicing COD 271 mg/L 154 mg/L 

Airfield Pavement Deicing Ammonia as Nitrogen 14.7 mg/L 

Table 3-3 summarizes the technology basis for NSPS. 

3.1.3 Pretreatment Standards for Existing Sources (PSES) 

 EPA is not proposing PSES for the Airport Deicing Category, based on information 

collected by the Agency. POTWs across the country are accepting wastewater associated with 

deicing runoff and EPA is not aware of any specific pass-through, interference or sludge 

contamination concerns for these POTWs. EPA is aware that high concentration and/or volume 

“slug” discharges of deicing stormwater can create POTW upset, and many of the airports that 

discharge to POTWs have airport-specific requirements on allowable chemical oxygen demand 

(COD) or BOD discharge loading per day. They may also have requirements for discharging at 

various concentration levels over time. 
Technical Development Document for Proposed Effluent 3. Summary and Scope of Regulation 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 3-2 

3.1.4 Pretreatment Standards for New Sources (PSNS) 

 As with existing sources, EPA is not proposing PSNS for the Airport Deicing Category, 

based on information collected during the data collection phase of this project. EPA does not 

expect any pass-through concerns with the discharge of deicing stormwaters to a POTW. 

Table 3-3. Summary of Proposed Airport Deicing Effluent Limitation Guidelines and 

Standards 

Technical Components 

Regulatory 

Level Technology Basis 

Airports ≥ 1,000 Annual Jet 

Departures and ≥10,000 Annual 

Departures 

Airports ≥ 1,000 Annual Jet 

Departures and <10,000 

Annual Departures 

BAT 1. 60% or 20% ADF 

capture 

2. Biological treatment 

3. Pavement deicer product 

substitution 

1. Capture 60% of available ADF (for 

airports having ≥460,000 gal. ADF 

usage) or capture 20% (for airports 

<460,000 gal. ADF usage) 

2. Treat wastewater to meet effluent 

limit for COD 

3. Certify use of non-urea-based 

pavement deicers 

or 

Meet effluent limit for ammonia 

1. Certify use of non-ureabased pavement deicers 

or 

Meet effluent limit for 

ammonia 

NSPS 1. 60% ADF Capture 

2. Biological treatment 

3. Pavement deicer product 

substitution 

1. Capture 60% of available ADF 

2. Treat wastewater to meet effluent 

limit for COD 

3. Certify use of non-urea-based 

pavement deicers 

or 

Meet effluent limit for ammonia 

1. Certify use of non-ureabased pavement deicers 

or 

Meet effluent limit for 

ammonia 

Note: All references to ADF are for normalized ADF, which is ADF less any water added by the manufacturer or 

customer before ADF application. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-1 

4. DATA COLLECTION ACTIVITIES

 To characterize airport deicing operations and to develop the proposed effluent limitation 

guidelines and standards, EPA collected and evaluated technical and economic data from a 

variety of sources. This section details the following data sources used for the Airport Deicing 

Category rulemaking effort: 

Section 4.1 – Preliminary Data Summary 

Section 4.2 – Site Visits 

Section 4.3 – Industry Questionnaires (Surveys) 

Section 4.4 – Field Sampling 

Section 4.5 – Permit Review 

Section 4.6 – Industry-Supplied Data 

Section 4.7 – Literature Reviews 

 For the development of the 2004 Effluent Guidelines Plan, the Agency reviewed 

available information on aircraft deicing/anti-icing fluid (ADF) use at airports. EPA found that 

the potential existed for airports to discharge nontrivial amounts of nonconventional and toxic 

pollutants and that ADF is not properly recaptured and reused or properly treated before 

discharge. However, due to the variety of ADFs in use and the limited information on the 

chemical composition of these ADFs, EPA was unable to estimate the toxic-weighted pollutant 

discharges associated with these discharges and the potential effluent reductions that could be 

achieved through application of more stringent control mechanisms. Therefore, the Agency 

initiated the data collection activities discussed in this section. 

4.1 Preliminary Data Summary

 EPA’s initial source of wastewater discharge information for the aviation industry was 

the Preliminary Data Summary (PDS): Airport Deicing Operations, which was published in 

August 2000 (USEPA, 2000). This study focused on approximately 200 U.S. airports with 

potentially significant deicing/anti-icing operations. For the study, EPA collected information 

from industry questionnaires, engineering site visits, wastewater sampling activities, meetings 

with industry and regulatory agencies, and technical and scientific literature. See Section 3.0 of 

the PDS for detailed information on the study’s data collection activities. 

 The questionnaires that were reviewed included the 1993 Screener Questionnaire for the 

Transportation Equipment Cleaning Industry, and a set of questionnaires distributed during the 

study to major and regional airports and airlines, technology vendors, and POTWs. 

 From September 1997 through March 1999, the Agency conducted 16 airport site visits 

and 6 sampling episodes to collect information about deicing processes, deicing equipment, and 

deicing wastewater generation, collection, handling, and treatment technologies. 

 EPA met with the Federal Aviation Administration (FAA), deicing fluid manufacturers 

and formulators, airlines, industry associations, technology vendors, and other interested parties 

to discuss environmental and operational issues related to aircraft deicing and anti-icing 

operations. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-2 

 Literature searches provided information on the toxicity, industry usage, and mitigation 

techniques for ADFs. The literature also covered topics such as alternative fluid types, pollution 

prevention practices, economic and financial data, and environmental impacts. 

4.2 Site Visits

 Between December 2004 and November 2005, EPA conducted 20 airport site visits to 

collect current information about aircraft and airfield deicing practices, deicing equipment, 

deicing stormwater generation, collection, handling, and control. During these site visits, EPA 

also evaluated potential sampling locations for the sampling program described in Section 4.4. 

 EPA used information collected from the PDS, updated airport literature searches, and 

other Agency-supplied data to assess potential airports for site visits. EPA also solicited 

recommendations from industry trade associations, including the Air Transport Association 

(ATA), the American Association of Airline Executives (AAAE) and Airports Council 

International-North America (ACI-NA). EPA considered the following criteria in evaluating 

which airports to visit: 

• Hub size and location of the airport; 

• Aircraft deicing fluid handling practices; 

• Deicing stormwater collection and control practices; and 

• ADF-contaminated stormwater discharge practices. 

 In general, EPA visited medium and large hub airports operating in northern climates that 

conduct aircraft and airfield deicing operations each winter. EPA also visited some small hub 

airports to evaluate potential issues related to an airport’s size. The Agency visited airports that 

use a variety of deicing practices (such as gate deicing, centralized deicing pads, deicing trucks 

and stationary booms, infrared deicing hangars) and various deicing stormwater collection and 

control technologies (such as dedicated deicing stormwater collection systems, stormwater 

treatment through biological systems, and glycol recovery systems). Table 4-1 lists the 20 

airports visited, the visit date, and EPA’s criteria for visiting each airport. 

 During the site visits, EPA collected the following information: 

• General airport and deicing operations information, including size and age of the 

airport, permit status, information on the entities that perform deicing operations 

(both aircraft and airfield), and current airline tenant information; 

• Description of the deicing/anti-icing operations conducted at the airport, including 

the types of equipment used, locations of deicing operations, and information on 

any pollution prevention or “state-of-the-art” systems in use at the airport that 

improved their deicing operations; 

• Deicing chemicals used, including ADF type (e.g., Type I-IV) and any chemical 

usage information available; 

• Description of the deicing stormwater collection and control systems used at the 

airport, including any glycol recovery or stormwater treatment systems and their 

effectiveness and any available cost information for these systems; and 

• Airport monitoring and discharge of deicing stormwater, including pollutants 

monitored and frequency of monitoring. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-3 

Table 4-1. Airports Visited and Reasons for Site Visits 

Airport Name 

Airport 

Code Date of Visit Criteria for Site Visit 

Washington Dulles 

International 

IAD 12/1/2004 Local large hub airport, ADF-contaminated stormwater 

collection and glycol recovery, indirect discharger 

Baltimore-Washington 

International 

BWI 12/15/2004 Local large hub airport, deicing pads, ADFcontaminated stormwater collection, indirect 

discharger 

Chicago O’Hare 

International 

ORD 1/26/2005 Large hub airport, ADF-contaminated stormwater 

collection with indirect discharge, upgrades to system 

since the PDS site visit 

General Mitchell 

International 

(Milwaukee) 

MKE 1/27/2005 Medium hub airport, ADF-contaminated stormwater 

collection and indirect discharge, extensive monitoring 

data in collaboration with U.S. Geological Survey 

(USGS) 

Detroit Metropolitan 

Wayne County 

DTW 1/28/2005 Large hub airport, deicing pads, ADF-contaminated 

stormwater collection with glycol recovery, both direct 

and indirect discharger 

Ronald Reagan 

Washington National 

DCA 2/1/2005 Local large hub airport, changes in ADF practices 

since PDS site visit, ADF-contaminated stormwater 

collection 

Syracuse Hancock 

International 

SYR 2/9/2005 Small hub airport, deicing pads, aerated stormwater 

lagoons, indirect discharger 

Albany International ALB 2/10/2005 Small hub airport, ADF-contaminated stormwater 

collection with anaerobic and aerobic treatment, direct 

discharger, upgrades to system since the PDS site visit 

Pittsburgh International PIT 2/10/2005 Large hub airport, deicing pads, glycol recovery and 

treatment (ultra filtration and reverse osmosis) of ADFcontaminated stormwater, direct discharger 

Cincinnati/Northern 

Kentucky International 

CVG 2/11/2005 Large hub airport, variety of ADF-contaminated 

stormwater-related activities, recommended by FAA as 

a site visit location, on-site aerobic treatment, direct 

and indirect discharger 

Richmond International RIC 2/16/2005 Local small hub airport 

Minneapolis-St. Paul 

International/WorldChamberlain 

MSP 2/18/2005 Large hub airport, ADF collection with glycol 

recovery, direct and indirect discharger 

James M Cox Dayton 

International 

DAY 2/25/2006 Small hub airport, centralized deicing with ADFcontaminated stormwater collection 

Portland International 

(Oregon) 

PDX 7/26/2005 Medium hub northwestern airport, indirectly 

discharges high strength deicing stormwater, sends low 

strength deicing stormwater to detention pond and then 

to direct discharge 

Seattle-Tacoma 

International 

SEA 7/27/2006 Large hub northwestern airport, industrial stormwater 

treatment on site 

LaGuardia (New York) LGA 10/11/2005 Large hub airport, direct discharger, part of New York 

City area visits 

John F. Kennedy 

International (New 

York) 

JFK 10/11/2005 Large hub airport with a high percentage of 

international flights, direct discharger, part of New 

York City area visits, future plans for infrared deicing 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

Table 4-1 (Continued) 

July 2009 4-4 

Airport Name 

Airport 

Code Date of Visit Criteria for Site Visit 

Newark Liberty 

International 

EWR 10/12/2005 Large hub airport, infrared technology since 1999 

Salt Lake City 

International 

SLC 11/8/2005 Large hub western airport, ADF-contaminated 

stormwater collection with glycol recovery 

Denver International DIA 11/9/2005 Large hub western airport, deicing pads, ADFcontaminated stormwater collection with glycol 

recovery 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-5 

This information is documented in the Site Visit Report (SVR) for each airport visited. The 

SVRs are located in the administrative record for this rulemaking. 

4.3 Industry Questionnaires (Surveys)

 EPA distributed three questionnaires to directly support the Airport Deicing rulemaking. 

Section 4.3.1 discusses the recipient selection process, distribution, and mail-out results for the 

three airport deicing questionnaires. Section 4.3.2 discusses the organization of and type of 

technical information requested in each questionnaire. 

4.3.1 Recipient Selection and Questionnaire Distribution 

 EPA distributed an airline screener questionnaire followed by a detailed airline 

questionnaire, and an airport questionnaire. The overall focus of the questionnaires was on 

airports and airlines that perform deicing and anti-icing on aircraft and/or airfield pavement. 

Airports were selected for the detailed airport questionnaire by airport type (i.e., large hub, 

medium hub, small hub, and non-hub), days and amount of snow or freezing precipitation, and 

the number of departures. EPA performed a census design for large and medium hub airports and 

a stratified random sample design for small and non-hub airports (see the statistical support 

memorandum DCN AD01208). 

 FAA classifies large commercial airports into size categories of “hubs,” based on the 

number of annual enplanements that occur at the airport. Enplanements represent the number of 

passengers boarding the plane for departure. Large hubs are airports that represent more than 1 

percent of total U.S. passenger enplanements. Medium hubs are defined as airports that account 

for more than 0.25 percent but less than 1 percent of total passenger enplanements. Small hubs 

enplane 0.05 to 0.25 percent of the total passenger enplanements. Airports with less than 0.05 

percent of the total passenger enplanements but more than 10,000 annual enplanements are 

considered non-hub primary airports. 

 EPA selected airlines for the airline screener questionnaire by the number of departures at 

the selected airports and then selected those airlines for the airline detailed questionnaire if 

deicing was performed on their aircraft at these airports. EPA used weighting factors to scale up 

the airport survey data to represent national estimates. Table 4-2 summarizes the response rates 

for the questionnaires. 

Table 4-2. Deicing Questionnaire Response Rates 

Questionnaire Type Distributed 

Returned 

Undelivered 

Returned 

Completed Not Returned 

Airport Deicing Detailed Questionnaire 153 0 (0%) 150 (98%) 3 (2%) 1

Airline Screener Questionnaire 72 1 (1%) 70 (97%) 1 (1%) 

Airline Deicing Detailed Questionnaire 58 0 (0%) 49 (84%) 9 (16%) 

1 EPA determined that one airport recipient was out of scope and removed it from the sample frame. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-6 

4.3.1.1 Airport Questionnaire 

 EPA selected 153 airports to receive the airport questionnaire and distributed the 

questionnaire to these airports in April 2006. Of the 153 airport questionnaires distributed, 150 

were returned. EPA removed one of the three non-respondent airports from the sample frame 

because it was a city airport operating as a tenant at a military airport. EPA determined that its 

selection was based on data for the military airport operations, not the city airport, and military 

airports were not included in the sample frame. 

4.3.1.2 Airline Screener Questionnaire 

 EPA selected 94 airlines as recipients of the screener questionnaire. The recipient group 

was comprised of a random sample of airlines with greater than 1,000 departures per year 

operating at the airports that were sent the airport questionnaire, and a judgment sample of small 

and foreign airlines for which additional information would be useful in developing effluent 

guidelines, but that were not captured into the random sample. In April 2006, the Agency 

distributed the airline screener questionnaire to 72 of the 94 selected airlines. The 22 remaining 

airlines were foreign carriers operating at the selected airports. EPA collected aircraft deicing 

and anti-icing information for these 22 foreign carriers through contacts with airport managers 

where the carriers operated. 

 Of the 72 screener questionnaires distributed, 70 were returned. Of the two not returned, 

one questionnaire was returned undelivered, as the airline had ceased operations. 

4.3.1.3 Airline Detailed Questionnaire 

 Using the responses from the airline screener questionnaire, EPA selected 58 airlines that 

responded that they deice planes directly to receive a more detailed questionnaire. This 

questionnaire was distributed in March 2007. The selection included 448 airline/airport 

combinations. The Agency categorized the airline/airport combinations according to the entity 

that performed most of the deicing for the 2002/2003, 2003/2004, and 2004/2005 winter seasons 

as listed below: 

• Airline combinations that deice their own aircraft; 

• Airline combinations that contract to fixed-base operators (FBOs) for deicing 

services; or 

• Airline combinations that contract to other airlines for deicing services. 

 Of the 58 airline detailed questionnaires sent, 49 were returned and 9 were not returned. 

4.3.2 Questionnaire Information Collected 

 EPA designed the questionnaires to collect current information with sufficient detail to 

support development of effluent guidelines. The questionnaires collected information on deicing 

operations performed on aircraft and airfield pavement, including deicing stormwater generation, 

collection, characterization, management, and treatment. The airline screener supported the 

selection of recipients for the airline detailed questionnaire. This section describes the technical 

information collected and the purpose of each of the three questionnaires. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-7 

4.3.2.1 Airport Questionnaire 

 EPA divided the airport deicing questionnaire into the following parts and sections: 

PART A: TECHNICAL INFORMATION 

Section 1: General Airport Information 

Section 2: Airport Deicing and Anti-Icing Operations 

Section 3: Deicing Stormwater Containment and/or Collection 

Section 4: Deicing Stormwater Treatment/Recovery 

Section 5: Analytical Data 

Section 6: Pollution Prevention Practices 

PART B: FINANCIAL AND ECONOMIC INFORMATION 

Section 1: Ownership and Management Structure 

Section 2: Airport Finances 

Section 3: Capital Expenditures 

Section 4: Airport Operations 

 Section 1 (Questions 1 through 24) requested information to identify the airport and 

primary contacts, to confirm that aircraft deicing/anti-icing was performed during the three 

designated winter seasons (2002/2003, 2003/2004, and 2004/2005), and to characterize deicing 

operations. This information included the destination of deicing/anti-icing stormwater, receiving 

surface waters, the entity that performed aircraft and/or airfield pavement deicing, and the 

number of deicing/anti-icing days per winter season. This information helped EPA update the 

industry profile, characterize deicing/anti-icing operations, and determine the proximity and 

types of ecosystems within and beyond airport boundaries 

 Section 2 (Questions 25 through 31) requested detailed information about airport 

deicing/anti-icing stormwater sources, flows, and destinations as well as deicing/anti-icing 

chemicals, materials, and practices. EPA used this information to develop an industry profile of 

deicing stormwater generation and collection, to determine baseline loadings using airfield 

deicing chemical usage, and to develop and evaluate possible regulatory technology options and 

compliance costs estimates. 

 Section 3 (Questions 32 through 39) requested information on the collection, 

containment, conveyance, discharge and/or disposal methods for deicing stormwater, and 

pollution prevention and best management practices. EPA used this information to develop an 

industry profile of deicing stormwater collection/containment/conveyance methods and to 

evaluate pollution prevention and best management practices. 

 Section 4 (Questions 40 through 51) requested information on deicing stormwater 

treatment technologies and units operated by the airport and included deicing stormwater 

treatment diagrams, design and operating specifications, sources of wastewater influent, 

treatment chemical additions, treatment operations and maintenance costs, and discharge 

practices. EPA used this information to develop control technology options, regulatory options, 

and compliance cost estimates. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-8 

 Section 5 (Questions 52 through 55) requested information concerning the availability of 

deicing stormwater characterization data, receiving water in-stream monitoring data, and/or data 

characterizing the effectiveness of treatment of deicing stormwater. EPA used this information to 

follow up with selected airports to request long-term monitoring data, to estimate pollutant 

discharge loadings, to characterize behavior of the discharge in the receiving water, to assess 

deicing stormwater treatment technologies, and to help assess environmental impacts. 

 Section 6 (Questions 56 through 68) requested information to evaluate the status of 

pollution prevention practices at each airport and to identify pollution prevention technologies. 

EPA used this information to identify appropriate practices as regulatory options and to prepare 

an industry profile of pollution prevention practices. 

 Part B of the questionnaire requested airport financial and economic information. Section 

1 requested information on the ownership and management structure that EPA used to develop 

the industry profile and to estimate economic impacts of an effluent guideline. Section 2 

requested information on operation finances that EPA used to project the potential impacts of the 

rule. Section 3 requested information on current capital airport expenditures that EPA used to 

assess the capability of airports to pay for deicing-related capital improvements. Section 4 

requested information on the finances for airport operations including the airport’s financial 

statement that EPA used to determine the airport’s cost of capital. 

4.3.2.2 Airline Screener Questionnaire 

 The airline screener questionnaire requested information on which entity performed most 

of the deicing/anti-icing operations on an airline’s aircraft, including the name of another airline, 

fixed base operator (FBO), or private contractor that performed the service. EPA used this 

information to identify potential airline detailed questionnaire recipients and to indicate the 

potential contribution of FBOs to deicing operations and to the discharge of ADF-contaminated 

stormwater. 

 The screener included three questions. Question 1 requested the contact information of 

the airline contact that could verify or clarify the screener information. Question 2 asked who 

performed most of the deicing/anti-icing on the respondent’s aircraft at specific airports and, if 

applicable, requested the identity of the other airline, FBO, or private contractor that performed 

the deicing. Question 3 provided an opportunity for the respondent to provide additional 

information or comment on the screener responses. 

4.3.2.3 Airline Detailed Questionnaire 

 EPA divided the airline detailed questionnaire into the following parts and sections: 

PART A: TECHNICAL INFORMATION 

Section 1: General Airline Information 

Section 2: Airline Deicing and Anti-Icing Operations (at each airport specified in 

Section 1) 

Section 3: Pollution Prevention Practices (at each airport specified in Section 1) 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-9 

PART B: DEICING COSTS AND OPERATIONS 

Section 1: Airline Deicing Costs and Operations 

Section 2: Airport-Specific Deicing Costs and Operations 

 Section 1 (Questions 1 through 4) requested verification of the airline name and address, 

and identification of the primary and secondary contacts to clarify or verify the technical 

questionnaire responses. 

 Section 2 (Questions 5 through 18) requested information on deicing/anti-icing 

operations performed on the airline’s aircraft and/or by the airline for another airline’s aircraft at 

each specified airport. The Agency used this information to: 

• Develop an industry profile of ADF usage and deicing stormwater generation; 

• Estimate pollutant loadings; 

• Characterize deicing stormwater; 

• Evaluate differences in airport deicing stormwater generation and characteristics; 

• Identify pollutants of concern; and 

• Identify opportunities for pollution prevention through chemical substitution and 

best management practices. 

 Section 3 (Questions 19 through 31) requested information on the airline’s pollution 

prevention practices including a description of each practice and any costs and/or savings from 

its implementation. The Agency evaluated this information to identify appropriate practices that 

could become part of regulatory options and to develop an industry profile. 

 Part B of the questionnaire requested airline financial and economic information. 

Section 1 requested information on ownership, aircraft deicing costs and operations, and the 

airline’s financial statement that EPA used to develop the industry economic profile and to 

conduct the economic analysis. Section 2 requested detailed information regarding airlinespecific deicing costs and operations at specific airport locations. The Agency also used this 

information for the industry economic profile and to determine the economic impacts of the rule. 

4.3.3 Questionnaire Technical Review, Coding, and Data Entry 

 EPA completed detailed technical reviews of the screener and the two detailed 

questionnaires for completeness, accuracy, and consistency of the responses. In some cases, the 

Agency followed up with the airport or airline by email or telephone to clarify responses or to 

obtain missing or incomplete technical information. During the technical review, EPA coded 

responses to facilitate entry of technical data into the airline screener and the airline and airport 

questionnaire databases. 

 The Agency developed databases containing the technical information provided by 

questionnaire respondents of each questionnaire. After detailed technical review and coding, 

EPA entered data from the questionnaires into the appropriate database using a double-key entry 

and verification procedure to identify and resolve differences between the two data entry tasks. 

The database dictionary for each questionnaire presents the database structure and codes and 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-10 

defines each field in the database files. These dictionaries are located in the administrative record 

for the Airport Deicing rulemaking.

4.4 Field Sampling

 EPA conducted sampling episodes at six airports from March 2005 through August 2006 

to characterize ADF and ADF-contaminated stormwater discharges and to evaluate treatment 

technologies for stormwater affected by aircraft and airfield deicing practices. EPA used existing 

industry profile information and information collected during airport site visits to determine the 

most appropriate locations for sampling. The Agency evaluated the following criteria for 

selecting sampling sites: 

• Size and location of the airport; 

• Deicing stormwater collection and control practices; and 

• ADF-contaminated stormwater discharge practices. 

 EPA conducted the episodes to characterize deicing stormwater and assess the 

capabilities and effectiveness of several different treatment technologies such as anaerobic 

treatment, aerobic treatment, distillation, reverse osmosis, mechanical vapor recompression, 

aeration, and chemical addition. Table 4-3 lists the airports selected for EPA sampling, the 

reason for selection, and the points that were sampled. 

4.5 Permit Review

 During the regulatory development process, EPA conducted a National Pollutant 

Discharge Elimination System (NPDES) permit review to understand what permit authorities are 

currently requiring of airports with respect to deicing stormwater control. The permit review 

performed three functions: 

1. Assessed the current state of deicing stormwater control; 

2. Helped evaluate the effectiveness of various deicing stormwater control measures; 

and 

3. Identified potential measures that EPA could use to further control deicing 

stormwater. 

The following discussion describes the process EPA used to select airports for permit review and 

to obtain and review NPDES permits for this analysis. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

1 QC samples may include source water, duplicate samples, trip blanks, equipment blanks, bottle blanks, field 

blanks. 

July 2009 4-11 

Table 4-3. Airports Selected for Sampling and the Reason for Their Selection 

Airport Name 

Airport 

Code 

Dates of 

Sampling Reason for Sampling Sample Points 

Detroit Metropolitan 

Wayne County 

Detroit, MI 

Episode 6508 

DTW 3/31/05 Collects highly 

concentrated ADF for 

recycling, significant 

stormwater volumes, 

direct and indirect 

discharger 

• Untreated deicing stormwater 

• Effluent from ADF contaminated 

stormwater collection pond 

• Effluent from pavement deicer 

stormwater collection pond 

• ADF, as applied 

• QC samples 1

Minneapolis/St. Paul 

International 

Minneapolis/St. Paul, 

MI 

Episode 6509 

MSP 4/28/05 On-site collection and 

recycling facility, direct 

and indirect discharger 

• High concentration ADFcontaminated stormwater storage 

tank 

• Low concentration ADFcontaminated stormwater storage 

tank 

• Influent to pavement deicer 

stormwater collection pond 

• Effluent from pavement deicer 

stormwater collection pond 

• ADF, as applied 

• QC samples 1

Albany International 

Albany, NY 

Episode 6523 

ALB 2/5/06-

2/10/06 

Reported recovery 

efficiency of 72% of 

applied ADF through 

ADF-contaminated 

stormwater collection 

with anaerobic and 

aerobic treatment 

• Influent to anaerobic treatment 

• Effluent from anaerobic treatment 

• Effluent from aerobic treatment 

• QC samples 1

Pittsburgh 

International 

Pittsburgh, PA 

Episode 6528 

PIT 2/26/06-

3/3/06 

Reported recovery 

efficiency of 60-66% of 

applied ADF through 

collection and treatment 

(ultrafiltration and 

reverse osmosis) of 

ADF-contaminated 

stormwater 

• Influent to RO treatment 

• Effluent from RO treatment 

• QC samples 1

Denver International 

Denver, CO 

Episode 6522 

DIA 3/26/06-

3/31/06 

ADF-contaminated 

stormwater collection 

with glycol recovery 

• Influent to MVRs 

• Influent to distillation column 

• Distillate from MVRs 

• Overhead from distillation column 

• Effluent from treatment 

• QC samples 1

Greater Rockford 

Rockford, IL 

Episode 6529 and 6530 

RFD 4/20/06 

and 

8/29/06 

On-site aerated lagoon 

treatment system (run in 

batch mode) for its 

deicing-contaminated 

stormwater 

Spring Sampling

• Influent to aerobic pond treatment 

• QC samples 1

Summer Sampling

• Effluent from aerobic pond 

treatment 

• QC samples 1
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-12 

4.5.1 Airport Selection for Permit Review 

 For this review, EPA selected the top 50 U.S. airports based on ADF usage. At the time 

of review, usage estimates from the airline survey were not available; therefore, EPA estimated 

the airports with the highest usage using a “weighting factor” based on the number of snow or 

freezing precipitation (SOFP) days and commercial departures as a measure of ADF usage. 

Table 4-4 displays the results of the weighting factor analysis and lists the 50 airports for which 

EPA reviewed permits. 

4.5.2 Obtaining NPDES Permits 

 From the list of selected airports for permit review, EPA identified those for which it 

already had permits. While airports were not required to submit permits as part of their survey 

response, some airports did so. Furthermore, there were some permits already available in the 

airport deicing record files. Therefore, as a first step, EPA reviewed the administrative record 

index and survey responses to identify in-house permit availability. 

 As a next step, EPA identified NPDES permit numbers for those permits not available inhouse. Some airports reported permit numbers in the airport questionnaire, so in these cases, 

EPA obtained the data from the questionnaire database. For the remaining airports, EPA 

determined permit numbers by searching for facilities on EPA’s Envirofacts search tool. The 

facilities were searched by facility name, location, SIC code (4581), or a combination of any of 

the three. In a few cases, there were airports for which EPA could not identify permit numbers 

from either the questionnaire or Envirofacts. For these airports, EPA searched the Internet or 

contacted permitting authorities or the airport directly to obtain a copy of the permit. 

After identifying the permit numbers, EPA obtained a copy of the permit from a state or regional 

permit database. If a permit was not available online, EPA contacted the appropriate regional, 

state, or local permitting authority to obtain a copy. If still unsuccessful in obtaining the permit, 

EPA contacted the airport directly to request a copy. 

4.5.3 Permit Review Process 

 The objectives of the permit review were to answer the following questions: 

• What are the monitoring requirements for deicing area outfalls? 

• What pollutants are monitored? 

• Are there numeric limits listed in the permit for deicing area outfalls? 

• What parameters are limited? 

• What are the limits for each parameter? 

• How were the limits developed? 

• Are there deicing operation best management practices (BMPs) required by the 

permit? 

• What BMPs are required? 

• When does the permit expire? 

• If it is a general permit, are there differences between the permit and the EPA 

Multi-Sector General Permit (MSGP)? 
4-13 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category July 2009 

Table 4-4. Top 50 Airports in the United States with the Highest ADF Usage, Estimated Based on Sno

Precipitation Days and Total Airport Departures 

Rank 

Airport 

ID Airport Code Airport Name State 

Snow or 

Freezing 

Precipitation 

Days 

Total Airpo

Departure

1 1006 ORD Chicago O'Hare International IL 26 467,721 2 1126 MSP Minneapolis - St Paul International – WoldChamberlain MN 41 246,286 3 1138 DTW Detroit Metropolitan Wayne County MI 31 250,629 4 1028 DEN Denver International CO 26 264,051 5 1012 ANC Ted Stevens Anchorage International AK 55 88,126 6 1053 BOS General Edward Lawrence Logan International 

(Boston) 

MA 26 186,253 

7 1113 CVG Cincinnati/Northern Kentucky International KY 17 247,165 8 1069 CLE Cleveland – Hopkins International OH 36 116,569 9 1142 IAD Washington Dulles International DC 17 238,635 

10 1107 PIT Pittsburgh International PA 31 125,143 11 1145 EWR Newark Liberty International NJ 16 203,082 12 1095 MDW Chicago Midway International IL 26 108,385 13 1139 PHL Philadelphia International PA 12 227,749 14 1136 MKE General Mitchell International (Milwaukee) WI 31 85,128 15 1029 LGA La Guardia (New York City) NY 12 192,127 16 1066 SLC Salt Lake City International UT 14 160,472 17 1010 FAI Fairbanks International AK 89 24,919 18 1011 STL Lambert - St Louis International MO 17 129,414 19 1148 MCI Kansas City International MO 27 76,016 20 1021 BUF Buffalo Niagara International NY 48 41,916 21 1089 JFK John F Kennedy International (New York City) NY 12 154,606 22 1024 IND Indianapolis International IN 21 83,769 23 1141 DCA Ronald Reagan Washington National DC 12 134,346 24 1129 BDL Bradley International (Windsor Locks) CT 31 51,389 25 1059 ROC Greater Rochester International NY 44 35,726 26 1111 CMH Port Columbus International OH 26 59,938 
4-14 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 

Table 4-4 (Continued) 

July 2009 

Rank 

Airport 

ID Airport Code Airport Name State 

Snow or 

Freezing 

Precipitation 

Days 

Total Airpo

Departure

27 1036 BWI Baltimore - Washington International MD 12 124,033 28 1026 DFW Dallas/Fort Worth International TX 4 360,933 29 1065 ALB Albany International NY 36 39,324 30 1080 SYR Syracuse Hancock International NY 44 30,840 31 1140 MEM Memphis International TN 8 166,910 32 1128 CLT Charlotte/Douglas International NC 6 214,396 33 1079 MHT Manchester NH 36 34,860 34 1058 GRR Gerald R Ford International (Grand Rapids) MI 48 25,015 35 1037 IAH George Bush Intercontinental (Houston) TX 4 248,339 36 1123 DAY James M Cox Dayton International OH 26 35,709 37 1020 ATL Hartsfield - Jackson Atlanta International GA 2 459,765 38 1121 PVD Theodore Francis Green State (Providence) RI 21 43,671 39 1147 RDU Raleigh - Durham International NC 10 86,302 40 1068 OMA Eppley Airfield (Omaha) NE 26 33,022 41 1105 GEG Spokane International WA 31 27,269 42 1108 SDF Louisville International - Standiford Field KY 12 65,586 43 1124 DSM Des Moines International IA 31 23,951 44 1074 SBN South Bend Regional IN 48 13,722 45 1153 CAK Akron - Canton Regional OH 41 14,911 46 1109 ILN Airborne Airpark (Wilmington) OH 21 25,508 47 1018 GSO Piedmont Triad International (Greensboro) NC 14 38,257 48 1100 TOL Toledo Express OH 36 14,385 49 1022 FWA Fort Wayne International IN 31 16,247 50 1051 HYA Barnstable Municipal - Boardman/Polando Field 

(Hyannis) 

MA 26 18,782 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-15 

 EPA also consulted Envirofacts as necessary to fill in any numeric limit data gaps from 

the permits and to cross-check for accuracy with the permitted limits. 

 To facilitate interpreting the results, EPA created a Microsoft® Access database to store 

the data obtained from the reviews. The database consists of two tables: a General Information 

table, and a Pollutant-Specific Information table. Tables 4-5 and 4-6 detail the database table 

descriptions. A summary of the permit review is presented in the memorandum Airport Deicing 

Operations NPDES Permit Review Summary (ERG, 2007). 

Table 4-5. Permit Review General Information Table 

Data Element Data Element Description 

AirportID The airport identification number used for the Airport Questionnaire. 

Permit_ID The airport NPDES identification number. 

Permit_Expiration The permit expiration date. 

Permit_BMPs A checkbox that identifies the presence of BMPs in the permit 

Permit_BMPs_Description A field that allows the BMPs in the permit to be listed. 

General_Permit A checkbox that identifies general permits. 

General_Permit_Difference 

from MSGP 

A field that provides a description of any differences that exist between general 

permits and the MSGP. 

Permit_Monitoring A checkbox that indicates if the permit requires monitoring. 

Permit_Limits A checkbox that indicates if the permit has numeric limits. 

Permit_Limit_Rationale A field that provides a description of what rationale was used to determine the limits 

in the permit. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-16 

Table 4-6. Permit Review Pollutant-Specific Information Table 

Data Element Data Element Description 

AirportID The airport identification number used for the detailed airport questionnaire. 

Permit_SamPoint The outfall/sampling area identifying number. 

Permit_Stream_Description Description of the outfall/sampling area. EPA tried to determine which outfalls 

receive deicing stormwater and to include only information from those outfalls. If 

the deicing outfalls cannot be determined, EPA included all outfalls. 

Pollutants that are monitored and/or limited at each outfall, using the following 

same codes that are used in the questionnaire database: 

Permit_Pollutant 

• BOD 

• COD 

• Fecal coliform 

• Metal 

• N 

• OG (oil & 

grease) 

• ORG (organic 

pollutants) 

• pH 

• TOC (total 

organic carbon) 

• TSS (total 

suspended 

solids) 

• Other 

OtherDesc If a pollutant is monitored/limited that does not have a code, “Other” was selected 

as the Permit_Pollutant and the pollutant name was entered in this field. This 

method of tracking pollutants was used to be consistent with the questionnaire 

database. 

PermitTimes 

PermitFreq 

To be consistent with the questionnaire database, the frequency of monitoring for 

each pollutant and outfall was recorded in the PermitTimes and PermitFreq fields. 

These fields allow the frequency to be reported in a number/unit manner. For 

example, a yearly report is entered as PermitTimes = 1 and PermitFreq = Year. 

Frequency Codes were also used in the PermitFreq field for daily (D), monthly 

(M), and quarterly (Q) reports. 

PermitLimitNumeric Numeric value of the permit limit for each pollutant and outfall. 

PermitLimitUnit Unit of the permit limit for each pollutant and outfall. 

LimitType Indicates whether the limit is a minimum value, maximum value, average, or 

simply a reporting requirement. This also incorporates the timespan of the limit 

using the frequency codes as above (e.g., daily maximum = DMAX; weekly 

average = WAVG). 

Season For deicing outfalls, the limits may vary by season for various parameters. Usually, 

this field is populated with Summer, Winter or All (as in year-round). 

4.6 Industry-Submitted Data

 Based on airport site visits, EPA sampling episodes, and responses to the airport 

questionnaire, EPA requested costing and long-term analytical data for managing deicing 

stormwater from specific airports. The Agency used this information to develop control 

technology options, compliance cost estimates, and to evaluate pollution prevention and best 

management practices. Tables 4-7 and 4-8 list those airports providing data, the type of system 

used to manage or treat the airport’s deicing stormwater, and the costing and/or analytical data 

submitted by the airport. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-17 

Table 4-7. Summary of Costing Data Provided by Industry 

Airport 

Type of Deicing Stormwater 

Management Costing Data Provided 

Akron-Canton Regional Anaerobic ADF-contaminated 

stormwater treatment system 

Capital and operating and maintenance costs 

for the airport’s new anaerobic fluidized bed 

(AFB) treatment system 

Albany International AFB/aerobic ADF-contaminated 

stormwater treatment system 

Capital and operating and maintenance costs 

for the airport’s AFB/aerobic treatment system

Cincinnati/Northern 

Kentucky International 

Glycol recovery and recycling 

system 

Capital and operating and maintenance costs 

for glycol collection and treatment 

Denver International Storage, recovery, and recycling; 

mechanical vapor recompression 

(MVR) and distillation system 

Capital costs for storage and the 

recycle/recovery system 

General Mitchell 

International 

Recovery and recycling; anaerobic 

digester 

Engineering and monitoring-related costs 

Minneapolis-St. Paul 

International –Wold 

Chamberlain 

ADF collection (deicing pads, plug 

and pump system) 

Capital costs for deicing pads and operating 

and maintenance costs for plug and pump 

system 

Pittsburgh International ADF collection at deicing pads; 

ADF-contaminated stormwater 

recovery and recycling 

Operating and maintenance costs for deicing 

pads

Seattle-Tacoma International ADF to industrial waste treatment 

plant 

Study costs for determining all known and 

reasonable technology (AKART) for handling 

aircraft deicing fluids 

Table 4-8. Summary of Long-Term Analytical Data Provided by Industry 

Airport 

Type of Deicing Stormwater 

Management 

Long-Term Analytical Data 

Provided 

Albany International Anaerobic/aerobic ADF-contaminated 

stormwater treatment 

Ammonia, COD 

Denver International Storage, recovery, and recycling; 

MVR/Distillation 

COD 

Detroit Metropolitan – 

Wayne County 

Recycling; distillation and recovery Ammonia 

Pittsburgh International Ultrafiltration/Reverse Osmosis; ADFcontaminated stormwater recovery and 

recycling 

Ammonia, urea 

Salt Lake City International ADF recovery and recycling COD 

4.7 Literature Reviews

 EPA conducted preliminary literature searches during the effluent guideline development 

process to supplement information acquired from site visits, sampling, and questionnaires. The 

purpose for the literature searches was three-fold: 

• To collect information on current airport deicing practices and trends, and gather 

information on state-of-the-art deicing stormwater treatment and/or glycol 

recovery technologies; 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-18 

• To collect available data from airports currently monitoring wastewater 

discharges; and 

• To obtain studies on the toxicity and environmental impact of current deicing 

fluids and deicing stormwater runoff. 

The following subsections list the data sources used for each literature search. 

4.7.1 Current Deicing Practices and Treatment Technologies 

 EPA performed keyword searches on three on-line search engines: 1) Cambridge 

Scientific Abstracts (CSA); 2) Dialog Version 5.0; and 3) GoogleTM. CSA provides access to 

over 50 databases published by CSA and its publishing partners, such as Aqualine, 

Environmental Sciences & Pollution Management Database, and Water Resources Abstracts. 

Dialog provides access to over 900 databases and handles more than 700,000 searches. The 

databases in Dialog that contain articles pertaining to airport deicing are BIOSIS Toxicology, 

Life Sciences Abstracts, Institute for Science Information, ProQuest Info & Learning, Ei 

Compendex, Enviroline, TGG National Newspaper Index, GEOBASE, NTIS, and Wilson 

Applied Science & Technology Abs. 

 The keywords for the literature searches included: airport deicing, aircraft, airfield, 

runway, aircraft deicing, aircraft deicing fluid (ADF), runway deicing, anti-icing, anti-icing fluid, 

airport stormwater, snow melt, centralized deicing pads, environmental assessment, 

environmental impact study (EIS), fish mortality, fish kill, and publicly owned treatment works 

(POTW). 

 EPA also used other on-line journal databases, such as Science Direct, Scirus, and 

Infotrak, for subject-specific articles. The treatment technologies featured in the articles found 

included: 

• Aerobic fluidized bed reactor/ biological treatment; 

• Aerated storage tanks; 

• Anaerobic co-digestion of aircraft deicing fluid and municipal wastewater sludge; 

• Batch-loaded anaerobic fluidized bed reactor; 

• Glycol reclamation/recycling and concentration; 

• Infrared technology; 

• Phytoremediation; 

• Plant-enhanced remediation; 

• Spray irrigation; 

• Subsurface-flow constructed wetlands; and 

• Surface detention ponds. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-19 

4.7.2 Current Airport Deicing Runoff Data 

 In addition to sampling and airport questionnaire data, EPA procured airport deicing 

runoff information from its Permit Compliance System (PCS) database and on-line journals. 

EPA downloaded all data reports from PCS for SIC code 4581: Airports, flying fields, and 

services. Not all airports report to their permitting authority, so the scope of runoff data is 

limited. The pollutant parameters include temperature, dissolved oxygen, biochemical oxygen 

demand (BOD), total suspended solids (TSS), metals, fecal coliform, aromatic hydrocarbon, pH, 

and oil and grease. For on-line searches, EPA procured journals that discussed deicing runoff 

containing ADF chemicals such as benzotriazole, propylene/ethylene glycol, and alklyphenol 

ethoxylates. EPA also collected Minneapolis/ St. Paul International Airport monitoring data 

during the site visit to that airport.

4.7.3 Chemical Information and Environmental Impact Studies 

 The methodology and databases used for chemical information and environmental impact 

study findings are similar to those used for the deicing practices and treatment technology 

search. EPA conducted searches for the following categories: 

• Chemical Properties of ADF Ingredients: physical appearance, structure, 

solubility, reactivity; 

• Human Toxicity: Inhalation, ingestion, dermal effect, oral rat lethal dose (LD50) 

values; 

• Aquatic Toxicity: Aquatic life lethal concentration (LC50) values; and 

• Chemical Fate and Transport: Soil sorption, fate in river, streams, and 

estuaries, breakdown pathways in anaerobic and aerobic conditions, and 

biodegradability. 

 In addition to journal articles, EPA gathered chemical information from Material Safety 

Data Sheets (MSDSs), Chemfinder.com, Wikipedia, the Pesticides Action Network (PAN) 

Pesticides Database, and the U.S. Patents Database. 

 The keywords for the pollutant term search included: propylene glycol, propylene glycolbased fluids, ethylene glycol, ethylene glycol-based fluids, urea, potassium acetate, calcium 

magnesium acetate (CMA), sodium acetate, sodium formate, dissolved oxygen, biodegradation, 

BOD, and ADF additives (e.g., tolytriazole, benzotriazole, nonylphenols, nonylphenol 

ethoxylate, etc.). 

4.7.4 Current Deicing Runoff Regulations 

 In addition to the searches described above, EPA searched the Internet using GoogleTM to 

review regulatory documents that contain guidelines, operation controls, management programs, 

laws, statues, and certification requirements related to airport deicing from the United States, 

Canada, Germany, Norway, and other European countries. 
Technical Development Document for Proposed Effluent 4. Data Collection Activities 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 4-20 

4.8 References

ERG. 2007. Memorandum from Jason Huckaby (ERG) to Brian D’Amico and Eric Strassler 

(U.S. EPA): Airport Deicing Operations NPDES Permit Review Summary. (April 16). DCN 

AD00611. 

USEPA.2008a. Airline Screener Questionnaire Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD00937. 

USEPA. 2008b. Airline Detailed Questionnaire Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD00938. 

USEPA. 2008c. Airport Questionnaire Database. U.S. Environmental Protection Agency/Office 

of Water. Washington, D.C. DCN AD00927. 

USEPA. 2000. Preliminary Data Summary: Airport Deicing Operations. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. EPA-821-R-00-016. Available online at 

http://www.epa.gov/guide/airport . DCN AD00005. 

USEPA. 2005. Supporting Statement: Survey of Airport Deicing Operations. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. DCN AD00447. 
Technical Development Document for Proposed Effluent 5. Overview of the Industry 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 5-1 

5. OVERVIEW OF THE INDUSTRY

The Airport Deicing Category includes the deicing and/or anti-icing of airfield pavement 

and aircraft. This section provides an overview of the airport deicing/anti-icing performed by 

selected airports and airlines. The overview includes statistics on the number and location of 

airports and airlines that perform deicing/anti-icing (Section 5.1), deicing and anti-icing practices 

performed on airfields and aircraft and methods used to collect and control deicing stormwater 

(Section 5.2), and the references used in this section (Section 5.3). 

5.1 Industry Statistics

 Data sources for statistics on the number and types of airports and airlines include 

responses to EPA’s airport and airline questionnaires, the Bureau of Transportation Statistics, 

Federal Aviation Administration (FAA), and EPA’s Preliminary Data Summary: Airport 

Deicing Operations (PDS) (USEPA, 2000). Data provided in responses to EPA questionnaires 

are based on deicing/anti-icing operations performed during the winter seasons of 2002/2003, 

2003/2004, and 2004/2005, hereafter referred to as the three winter seasons. 

5.1.1 Airports 

 The North American Industry Classification System (NAICS) identification number 

applicable to airport deicing is 488119: Other Airport Operations. The U.S. Census Bureau 

describes this industry as establishments primarily engaged in the following: (1) operating 

international, national, or civil airports or public flying fields, or (2) supporting airport 

operations, such as runway maintenance services, hangar rental, and/or cargo handling services. 

 The airport questionnaire data presented in this section are based on the 150 respondents 

to EPA’s airport questionnaire. In some cases, EPA applied weighting factors to the information 

provided by selected airport questionnaire recipients to scale up the questionnaire data to 

represent national estimates. 

5.1.1.1 Number and Types of Airports 

 FAA’s general categories of airports include commercial, general aviation, and relievers. 

Commercial airports are public airports receiving scheduled passenger service and having more 

than 2,500 enplaned passengers (number of passengers boarding a plane for departure) each year. 

General aviation airports have less than 2,500 enplanements per year or do not receive scheduled 

commercial service. Relievers are high-capacity general aviation airports in major metropolitan 

areas, and provide an alternative for small aircraft using busy commercial airports. 

 Airports may be further classified into several different categories, depending on the size 

and activity level of the airport. Often both of these factors can be determined by the number of 

enplanements or operations (number of arrivals and departures) at the airport in a given year. 

FAA classifies large commercial airports into “hubs,” based on the number of annual 

enplanements that occur at the airport. Large hubs are defined as airports with more than one 

percent of total U.S. passenger enplanements. Medium hubs are defined as airports with more 

than 0.25 percent but less than 1 percent of total passenger enplanements. Small hubs account for 

0.05 to 0.25 percent of the total passenger enplanements. Airports with less than 0.05 percent of 

the total passenger enplanements but more than 10,000 annual enplanements are considered non-
Technical Development Document for Proposed Effluent 5. Overview of the Industry 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 5-2 

hub primary airports. Nonprimary commercial services are those airports that have 2,500 to 

10,000 enplanements a year. 

 According to FAA 2004 data and the FAA’s National Plan of Integrated Airport Systems 

(NPIAS) Report to Congress, about 3,344 airports operated in the United States in 2004. Table 5-

1 identifies the number of airports by type as defined by number of enplanements. For all airport 

types, excluding general aviation airports, the totals in Table 5-1 represent counts for January 

through December 2004. FAA’s designation of hub status depends on the percent of total 

passenger boardings occurring at each airport, resulting in variation in the number of airports in 

each hub category from year to year. 

Table 5-1. Number of U.S. Airports by Airport Type in 2004 

Airport Type Number of Airports 

Large Hub 33 

Medium Hub 36 

Small Hub 67 

Non-hub 231 

Other Nonprimary 130 

General Aviation 1 2,573 

General Aviation Relievers 1 274 

TOTAL 3,344 

1 General aviation and general aviation reliever airports (open to the public) from the NPIAS Report to 

Congress. (USDOT, 2008a) 

Note: Airport counts will differ depending on the source and year of data represented. 

EPA distributed the airport questionnaire to 153 airports that included, based on 2004 

information, all large hub, all medium hub, and a statistical sampling of small hub and non-hub 

airports, as well as some general aviation/cargo, and other nonprimary airports. EPA determined 

that one airport recipient was out of scope and removed it from the sample frame. EPA received 

responses from 150 of these airports. The estimated total number of airports nationally that 

perform deicing and/or anti-icing of airfield pavement and/or aircraft during the three winter 

seasons surveyed by EPA is 334. By airport type, this includes 28 large hubs, 36 medium hubs, 

40 small hubs, 226 non-hubs, and 4 general aviation/cargo airports. 

5.1.1.2 Geographic Location of Deicing Airports 

 The location of the airport and its climate have a direct impact on deicing operations. 

Airport deicing/anti-icing operations occurred in 44 states in the three winter seasons. As shown 

below, the FAA divides the United States into the following nine regions: 
Technical Development Document for Proposed Effluent 5. Overview of the Industry 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 5-3 

Region State 

Alaskan AK 

Central IA, KS, MO 

Eastern DE, MD, NJ, NY, PA, VA, WV 

Great Lakes IL, IN, MI, MN, ND, OH, SD, WI 

New England CT, ME, MA, NH, RI, VT 

Northwest Mountain CO, ID, MT, OR, UT, WA, WY 

Southern AL, FL, GA, KY, MS, NC, PR, TN, VI 

Southwest AR, LA, NM, OK, TX 

Western-Pacific AZ, CA, HI, NV, GU, AS, MH 

Source: FAA, “FAA Regional Offices,” 

http://www.faa.gov/about/office_org/headquarters_offices/arp/regional_offices/. (U.S. DOT, 2008b). 

Table 5-2 summarizes the regions for the airports that reported deicing in the EPA airport 

questionnaire for the three winter seasons surveyed by EPA. (Note: these are not national 

estimates.) The Great Lakes and Eastern regions reported the highest number of deicing airports. 

Table 5-2. Deicing Airports by FAA Region for the Three Winter Seasons 

Region 

Airports Reporting Deicing and/or Anti-Icing in EPA 

Airport Questionnaire 

Great Lakes 31 

Eastern 22 

Southern 20 

Northwest Mountain 17 

Western-Pacific 15 

Southwest 14 

Alaskan 10 

New England 6 

Central 5 

Source: EPA airport questionnaire database (USEPA, 2008c). 

5.1.1.3 Weather Impacts on Airport Deicing/Anti-Icing 

 Airports conduct deicing/anti-icing operations when weather conditions, such as 

precipitation and/or temperature, have the potential to cause icing. Precipitation includes 

snowfall, rainfall, sleet (including freezing rain), and ice. The type of precipitation affects the 

volume and type of deicing/anti-icing chemicals used on aircraft and airfield pavement. For 

example, freezing rain requires the most deicing/anti-icing agent usage because the rain freezes 

on contact and coats the aircraft or airfield pavement to form a solid layer of ice. Dry-weather 

deicing is performed when the ambient temperature is cold enough to form ice on aircraft wings 

and surfaces (below 55° F), and generally requires a small volume of aircraft deicing/anti-icing 

fluids (ADF). 

 The duration of the deicing/anti-icing season is also determined by the climate at an 

airport location. Airfield pavement deicing can begin as early as September and continue through 
Technical Development Document for Proposed Effluent 5. Overview of the Industry 

Limitation Guidelines and Standards for the Airport Deicing Category 

May in colder climates and/or areas with high numbers of snow or freezing precipitation days. 

The national estimate of airports performing airfield pavement deicing is 215, which is lower 

than the national estimate of airports performing deicing operations overall. The difference is 

that there are airports that have some aircraft deicing (usually defrost deicing) but no airfield 

pavement deicing. In general, these airports are located in warm and/or dry weather climates 

with minimal winter storm events. For airfield pavement deicing, December, January, and 

February are the peak deicing months, and September and May have the lowest occurrences of 

airfield pavement deicing. Figure 5-2 presents the percentage of these 215 airports deicing 

airfield pavement for each month. The time frame during which an airport conducts deicing 

during a typical winter season ranges from two to nine months, and a majority of airports 

typically conduct deicing/anti-icing operations for five months a season. For the three winter 

seasons surveyed by EPA, the average reported number of airfield pavement deicing days among 

these 215 airports ranges from 0.3 to 240 days. 

71%

69%

61%

27%

5%

0% 0% 0%

5%

24%

55%

71%

0%

10%

20%

30%

40%

50%

60%

70%

80%

January

February

March

April

May

June

July

August

September

October

November

December

Month

Percentage

Figure 5-1. Percentage of Airports Deicing Airfield Pavement Each Month

5.1.1.4 Destination of Airport Deicing Stormwater 

 Airport questionnaire respondents reported direct, indirect, and zero discharge of deicing 

stormwater. Direct dischargers discharge deicing stormwater directly to U.S. surface waters, 

such as creeks, rivers, ponds, lakes, or oceans. Indirect dischargers convey deicing stormwater by 

pipe, conduit, or hauling to a publicly owned or other treatment works. A zero discharger 

disposes of deicing stormwater using methods other than direct or indirect discharge. Figure 5-3

presents the discharge status of airports by destination. Nationally, EPA estimates that 176 

July 2009 5-4 
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Limitation Guidelines and Standards for the Airport Deicing Category 

airports discharge to surface water only, 52 airports discharge both directly to surface water and 

indirectly to a publicly owned treatment works (POTW), 10 airports discharge to a POTW only, 

and 96 airports have zero discharge. 

 A majority of the zero dischargers reported conducting aircraft deicing only (i.e., no 

deicing of airfield pavement). These airports generally are in warm and/or dry weather climates 

and have minimal dry weather (defrost) deicing. For airports with minimal deicing, it is assumed 

that some portion of the ADF applied is lost as fugitive emissions during aircraft taxiing and 

take-off and EPA relied on the airport’s questionnaire response in assuming that no residual 

ADF from those fugitive emissions was likely to result in a direct discharge. Airports reported 

various methods for maintaining zero discharge that included evaporation, storage in surface 

impoundments, contract hauling, and recycle/recovery of deicing stormwater. The most common 

zero discharge method reported was evaporation. 

 It should be noted, that even though these airports are considered to be zero discharge for 

the purpose of this regulation due to the nature of the limited aircraft deicing that occurs, there 

may still be direct discharges at these facilities of stormwater that is not associated with aircraft 

deicing materials. 

Direct Discharge 

Only

52%

Direct and 

Indirect 

Discharge

16%

Indirect 

Discharge Only

3%

Zero Discharge

29%

Figure 5-2. Discharge Status of Airports 

5.1.2 Airlines 

 The NAICS code for airlines is 481: Air Transportation. Specific NAICS codes for 

respondents to the airline deicing questionnaires are: (1) 481111: Scheduled Passenger Air 

Transportation described by the U. S. Census Bureau as establishments primarily engaged in 

providing air transportation of passengers or passengers and freight over regular routes and on 

regular schedules; and (2) 481112: Scheduled Freight Air Transportation described by the U.S. 

Census Bureau as establishments primarily engaged in providing air transportation of cargo 

without transporting passengers over regular routes and on regular schedules. 

July 2009 5-5 
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July 2009 5-6 

 The airline data presented in this section are based on the 49 respondents to EPA’s airline 

detailed questionnaire and additional information from the 70 respondents to EPA’s airline 

screener questionnaire. Statistics for airlines do not have weighting factors and are based on the 

actual number of respondents. 

5.1.2.1 Types of Airlines 

 The four classifications of airlines are major, national, regional, and cargo and are based 

on the type of service they offer and their annual revenues. Classification is based on the 

economic and financial aspects of their aircraft fleet. Table 5-3 lists the criteria for the four 

classifications. 

Table 5-3. Airline Classifications 

Airline Type Annual Revenues Type of Service Aircraft Fleet 

Major >$100 million Regular schedules Large jets: >60 seats 

Payload >18,000 lbs 

National $100 million to $1 billion Regular schedules Medium and large jets 

Regional: Limited to single U.S. region

Large $20 million to $100 million Scheduled >60 seats 

Medium <$20 million Scheduled Lesser or greater than 60 seats 

Small 

(commuters) 

No revenue cut-off Scheduled <30 seats 

Cargo No revenue cut-off Scheduled Passenger aircraft with seats 

removed 

Source: Preliminary Data Summary: Airport Deicing Operations (Revised) (USEPA, 2000). 

 There were 20 major airlines in the United States in 2006. Many national airlines 

typically serve multiple U.S. regions whereas regional airlines are generally limited to a single 

region of the country. 

 Small regional airlines are the largest segment of the regional airline business. Regional 

airlines may be private business carriers, commercial airlines, charter airlines, or provide a 

combination of these services. Private business carriers represent about 60 percent of regional 

airline flights. Regional airlines serve all airports served by major airlines as well as smaller 

airports that are not served by any major airline. They typically operate out of one gate area 

unless they are affiliates of major airlines and operate at the gates of their affiliate. Regional 

airlines conduct a disproportionately large number of flight operations per passenger because 

their aircraft are smaller and carry fewer passengers per operation. 

 EPA administered the airline screener and detailed questionnaires to airlines with greater 

than 1,000 departures at specific airports that were selected to receive the airport questionnaire. 

The airline screener was distributed to 72 airlines, and 58 airlines received the detailed 

questionnaire. The airline detailed questionnaire recipients included major (16), national (17), 

regional (6), small or commuter (2), small certified (6), and cargo (1) airlines and requested 

information for one or more airport locations. EPA also requested information from 10 foreign 
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July 2009 5-7 

airlines that operated at U.S. airports. EPA received responses from 70 screener recipients and 49 

detailed questionnaire recipients. 

 All respondents to the airline detailed questionnaire reported conducting deicing/antiicing operations on their aircraft at a total of 57 airport locations. 

5.1.2.2 Types of Airline/Airport Relationships 

The relationship between airports and airlines regarding deicing operations is one of 

dependency and cooperation. Airports and airlines conduct deicing using chemical and 

nonchemical methods in the same airfield locations and both contribute pollutants to deicing 

stormwater. Airlines may conduct deicing on their own aircraft, deicing for other airlines, and/or 

may also use fixed-base operators (FBOs). An airline’s deicing methods must be approved by the 

FAA for air safety. Airports provide the collection and control systems to contain and/or treat 

deicing stormwater generated as a result of aircraft and airfield deicing. However, both airports 

and airlines implement pollution prevention practices such as evaluating application rates, using 

alternate chemicals, pretreating pavement and aircraft, and manually removing snow and ice to 

reduce the quantity of pollutants discharged and the amount of deicing stormwater generated. 

5.2 Industry Practices

 Airport deicing and anti-icing operations involve chemical and mechanical methods and 

are conducted at varied locations and by different entities. This subsection discusses these 

practices and pollution prevention methods used by airports and airlines as reported by 

respondents to the airport and airline deicing questionnaires. 

5.2.1 Airfield Deicing Practices 

 Airfield pavement deicing/anti-icing removes or prevents the accumulation of frost, 

snow, or ice on runways, taxiways, aprons, gates, and ramps. A combination of mechanical 

methods and chemical deicing/anti-icing agents are used, and these methods are typically 

conducted by airport personnel, FBOs, or private contractors. To reduce the quantity of 

pollutants or the amount of deicing stormwater, airports also use various pollution prevention 

measures. 

 Responses to EPA’s airport questionnaire indicated that airport personnel (67 percent of 

respondents) typically have primary responsibility for airfield pavement deicing/anti-icing. The 

remainder of airports reported that a combination of FBO/private contractor (13 percent), 

airlines/tenants (9 percent), military (11 percent), and other entities (4 percent) also conduct 

deicing. Airlines and tenants may be responsible for deicing/anti-icing their respective gates or 

leased areas. Responses to the questionnaire also indicated that most airports use a combination 

of mechanical and chemical deicing/anti-icing methods to remove snow or freezing precipitation 

(ice or sleet) from their airfield pavements. 

5.2.1.1 Chemical Deicing/Anti-Icing 

 The type of precipitation and temperature affect the volume and type of deicing agents 

required for deicing/anti-icing. Common pavement deicing/anti-icing agents used at airports 

include potassium acetate, sand, airside urea, sodium acetate, glycol-based fluids, and sodium 
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Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 5-8 

formate, as reported by respondents to EPA’s airport questionnaire. Potassium acetate and 

propylene glycol-based fluids were reported as the top deicing/anti-icing chemicals (by weight) 

used on airfield pavement during the three winter seasons surveyed by EPA; some respondents 

also reported using a mixture of these agents as well as heated sand. Table 5-4 provides national 

estimates of the number of airports using these agents. Airports purchase primarily ready-toapply rather than concentrated formulations of these chemicals. See Section 6.1 for a detailed 

discussion of deicing chemical usage. 

Table 5-4. National Estimate of Airports Using Deicing Chemicals or Materials 

Number of Airports Using Deicing Chemical/Material Deicing/Anti-Icing 

Chemical or 

Material 2002/2003 2003/2004 2004/2005 Average 

Percentage of 

Airports Using 

Deicing Chemical/

Material 

Potassium Acetate 94 104 111 103 31 

Sand 103 104 98 102 30 

Airside Urea 58 60 59 59 17 

Sodium Acetate 39 34 33 35 10 

Propylene GlycolBased Fluids 16 16 16 16 5 

Sodium Formate 22 1 23 15 5 

Ethylene GlycolBased Fluids 6 6 6 6 2 

Source: EPA airport questionnaire responses (scaled to national estimates) (USEPA, 2008c). 

5.2.1.2 Mechanical and Nonchemical Deicing/Anti-Icing 

 Mechanical methods, such as plows, brushes, blowers, and shovels for snow removal, are 

the primary forms of airfield pavement deicing and may be used in combination with chemical 

methods. One facility uses heated pavement through pavement temperature sensors to prevent 

airfield pavement from icing. Of the estimated 215 airports that conduct pavement deicing, EPA 

estimates that 212 (99 percent) use mechanical methods on airfield pavement. 

5.2.1.3 Pollution Prevention Practices 

 To reduce the quantity of pollutants discharged and the amount of deicing stormwater 

generated, airports implement various pollution prevention practices that control pollution from 

airport deicing chemicals (e.g., glycol) thus minimizing pollutant loads through reductions in 

chemical usage. Physical snow removal, specialized employee training, and pretreatment of 

airfields in advance of precipitation are the most common practices used by airports. The 

national estimate of airports implementing one or more pollution prevention practices is 244. 

Table 5-5 summarizes EPA’s national estimates of the number and percentage of airports that 

used airfield pollution prevention practices. See Section 9.1 for detailed descriptions of the 

pollution prevention practices used by airports. 
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Table 5-5. Summary of Airfield Pollution Prevention Practices 

Pollution Prevention Practice 

Estimated Number of 

Airports Using Practice 

Percentage of Airports 

Using Practice 

Physical removal of snow or freezing precipitation 232 69 

Specialized employee training 153 46 

Pretreatment of airfield in advance of precipitation 101 30 

Runway ice detection system 95 28 

Enhanced weather forecasting 77 23 

Heated sand 74 22 

Evaluation of application rates of deicing fluids 56 17 

Use of alternative chemicals 40 12 

Use of prewet dry chemical constituents 32 10 

Other 88 26 

Source: EPA airport questionnaire database (scaled to national estimates) (USEPA, 2000c). 

5.2.2 Aircraft Deicing Practices 

 Aircraft deicing involves removing frost, snow, or ice from aircraft. Aircraft anti-icing 

entails preventing frost, snow, or ice from accumulating on surfaces. Both chemical and 

nonchemical- deicing/anti-icing methods are conducted on aircraft at varied airport locations and 

by different entities. The FAA also influences aircraft deicing, as it has approval authority for the 

deicing/anti-icing practices and procedures selected by the airlines. Airlines also perform 

pollution prevention practices similar to airports to reduce the quantity of pollutants discharged 

and/or reduce the amount of deicing stormwater generated. 

 Aircraft deicing may be conducted by an airline, FBO, or private contractor. Often, larger 

airline carriers deice their own aircraft and possibly the aircraft of other airlines. In addition, the 

entity conducting aircraft deicing for an airline may vary depending on the airport location. All 

of the airline questionnaire respondents reported deicing their own aircraft at one or more of their 

airport locations. Airline respondents also reported FBOs (84 percent of the airline respondents) 

and/or another airline (56 percent of the airline respondents) deiced their aircraft at some of their 

airport locations. 

 Aircraft deicing is conducted at a variety of airport locations and most commonly at 

deicing pads and terminal gates and apron areas. Airline respondents reported aircraft deicing at 

the following locations including the percent of the airline respondents reporting using a 

location: 

• Deicing pad (80 percent); 

• Passenger terminal gates/apron areas (78 percent); 

• Aircraft parking aprons (46 percent); 

• Airfield ramps (42 percent); 

• Taxiways (24 percent); 

• Cargo apron areas (16 percent); and 

• Other locations (12 percent) (e.g., hangar, etc.). 
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July 2009 5-10 

5.2.2.1 Chemical Deicing/Anti-Icing 

 The type of precipitation and temperature determines the volume and type of deicing 

chemicals required to deice/anti-ice aircraft. Two types of aircraft deicing are conducted: wetweather and dry-weather. Wet-weather deicing is conducted when snow, sleet, or freezing rain 

accumulates on the aircraft. Dry-weather deicing is conducted when frost or ice forms on the 

aircraft due to changes in the ambient temperature or when fuel tanks become cooled during 

high-altitude flight, and forming ice at lower altitudes and after landing. Dry-weather deicing 

requires significantly smaller volumes of ADFs than wet-weather deicing. 

 Aircraft deicing/anti-icing chemicals are categorized into four classes: Type I, Type II, 

Type III, and Type IV. Not all types are currently used. Airlines surveyed by EPA reported 

consistently using only Type I and Type IV fluids. ADFs vary by composition and allowable 

holdover times (i.e., the amount of time the residual fluid protects aircraft from ice formation). 

They generally contain either ethylene glycol or propylene glycol, water, and additives to 

remove or prevent ice and snow. Type I ADF is used to remove ice and snow that has 

accumulated on aircraft, and Type IV fluids are used for anti-icing to increase holdover times for 

an aircraft prior to takeoff. Deicing fluids are usually heated prior to application, while anti-icing 

fluids are typically applied at ambient temperatures. 

 All fluids are usually applied under pressure using a nozzle, often from mobile deicing 

trucks (reported by 31 airlines). Below are additional types of ADF application equipment used, 

as reported in responses to the airline questionnaire: 

• Other equipment (5 respondents) (e.g., brooms, ground sprayer and ladder, 

palletized equipment and fork lift, towed tower, small portable unit, selfcontained mobile unit); 

• Fixed boom (3 respondents); and 

• Handheld bottle/container (1 respondent). 

 Table 5-6 identifies the type of ADF fluids purchased by airlines that deiced their own 

aircraft during the three winter seasons, as well as the average across those seasons, based on the 

49 airline respondents to the airline detailed questionnaire. Table 5-7 lists the ADF fluids 

purchased by an FBO during the three winter seasons and the average across those seasons, as 

reported by 42 airline respondents. As shown in the tables, Type I and Type IV propylene glycol 

are the most commonly purchased ADF fluids for deicing aircraft, both by airlines that deice 

their own aircraft and airlines that use FBOs. 
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Table 5-6. Deicing/Anti-Icing Chemicals Purchased by Airlines that Deiced Their Own 

Aircraft 

Number of Airlines Purchasing Chemicals Deicing/Anti-Icing 

Chemical 2002/2003 2003/2004 2004/2005 

Average Number of 

Airlines Purchasing 

Chemicals 

Type I Propylene Glycol 29 29 28 29 

Type IV Propylene Glycol 22 22 23 22 

Type I Ethylene Glycol 8 8 8 8 

Type IV Ethylene Glycol 6 5 4 5 

Type II Propylene Glycol 0 0 1 1 

Source: EPA airline detailed questionnaire database (USEPA, 2008b). 

Table 5-7. Deicing/Anti-Icing Chemicals Purchased for Aircraft Deiced by an FBO 

Number of Airlines for Chemicals Purchased by an 

Deicing/Anti-Icing FBO 

Chemical 2002/2003 2003/2004 2004/2005 

Average Number of 

Airlines for Chemicals 

Purchased by an FBO 

Type I Propylene Glycol 35 36 39 37 

Type IV Propylene Glycol 31 35 37 34 

Type I Ethylene Glycol 17 13 13 14 

Type IV Ethylene Glycol 13 9 9 10 

Type II Propylene Glycol 0 2 1 1 

Type II Ethylene Glycol 0 0 1 1 

Source: EPA airline detailed questionnaire database (USEPA, 2008b). 

5.2.2.2 Mechanical and Nonchemical Deicing/Anti-Icing 

 Mechanical and other nonchemical methods used to deice aircraft include brooms, ropes, 

hot water, infrared heating, and forced air. Brooms and ropes are not the primary method of 

aircraft deicing, especially wet-weather deicing, because they are so time- and labor-intensive, 

but rather used in combination with chemical deicing. Forced air/hot air systems are used to blow 

or melt snow and ice from aircraft surfaces. Infrared heating deicing systems consist of an open 

hangar-type structure with infrared generators suspended from the ceiling. The infrared 

wavelengths are targeted to heat ice and snow, and minimize heating of aircraft components. 

This system reduces the volume of ADF fluid required, but cannot provide anti-icing protection. 

Aircraft may also be stored in a hangar to prevent snow or ice from accumulating if a storm 

event is predicted. The most common methods of deicing/anti-icing used by airline questionnaire 

respondents are mechanical methods and hangar storage. Table 5-8 and Table 5-9 summarize the 

use of these methods for deicing/anti-icing aircraft by airlines and by FBOs, respectively. 
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Table 5-8. Summary of Mechanical and Nonchemical Aircraft Deicing Methods Used by an 

Airline 

Mechanical/Nonchemical Number of Airlines 

Method 2003/2004 2003/2004 2004/2005 

Average Number 

of Airlines 

Mechanical (e.g., brooms, ropes) 22 21 21 21 

Hangar storage 15 16 16 16 

Forced air 9 7 7 8 

Hot water 5 4 4 4 

Infrared heating 1 1 1 1 

Source: EPA airline detailed questionnaire database (USEPA, 2008b). 

Table 5-9. Summary of Mechanical and Nonchemical Aircraft Deicing Methods Used By 

FBOs 

Mechanical/Nonchemical Number of Airlines 

Method 2003/2004 2003/2004 2004/2005 

Average Number 

of Airlines 

Mechanical (e.g., brooms, ropes) 10 10 10 10 

Hangar storage 5 5 5 5 

Forced air 4 5 5 5 

Hot water 3 4 4 4 

Infrared heating 0 0 0 0 

Source: EPA airline detailed questionnaire database (USEPA, 2008b). 

5.2.2.3 Pollution Prevention Practices 

 To reduce the quantity of pollutants discharged and the amount of deicing stormwater 

generated, airlines implement pollution prevention practices at various airports. These practices 

control pollution from aircraft deicing chemicals and minimize pollutant loads. Specialized 

training, implementation of a pollution prevention policy, and physical snow removal are the 

most common pollution prevention practices used by airlines. Table 5-10 summarizes airline 

pollution prevention practices reported in response to the airline detailed questionnaire. See 

Section 9 for detailed descriptions of the pollution prevention practices used by airlines. 
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Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 5-13 

Table 5-10. Summary of Aircraft Pollution Prevention Practices 

Pollution Prevention Practice 

Number of Airlines 

Reporting Practice 

Specialized employee training 43 

Instituting pollution prevention policy 43 

Physical removal of snow or freezing precipitation 31 

Overnight pretreatment/storage of aircraft 30 

Custom fluid blending 27 

Enhanced weather forecasting 25 

Evaluation of application rates of deicing fluids 24 

Pretreating aircraft with hot water 9 

Use of alternative chemicals 2 

Other 30 

 Source: EPA airline detailed questionnaire database (USEPA, 2008b). 

5.2.3 Airport Deicing Stormwater Collection and Control 

 Deicing and anti-icing operations are conducted at multiple locations of the airfield, and 

the fluids are widely dispersed during and after application via ramp runoff, taxiway drippage, 

and residual on aircraft. Deicing stormwater is contained and collected by implementing 

designated deicing areas, stormwater drainage systems, glycol recovery, storage tanks, 

containment ponds, and plug and pump systems. Typical sources of deicing stormwater are: 

• Terminal gates and aprons/areas; 

• Aircraft deicing pads; 

• Taxiways; 

• Airfield ramps; 

• Runways; 

• Cargo apron areas; 

• Maintenance hangar ramps; 

• Aircraft parking areas; 

• Military bases; and 

• ADF-contaminated snow dumps. 

 Table 5-11 summarizes the collection and control methods used by airports. Based on 

responses to the airport questionnaire, an estimated 246 U.S. airports use containment, collection 

and/or conveyance measures to control the discharge of deicing stormwaters to surface waters 

and/or POTWs. Stormwater drainage systems and containment ponds and basins are used by 

most of the airports. See Section 9.0 for detailed discussions of deicing stormwater collection 

and control methods used by the airport deicing category. 
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Limitation Guidelines and Standards for the Airport Deicing Category 

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Table 5-11. Summary of Airport Collection, Containment, and Conveyance Methods 

Collection/Containment/Conveyance Method 

Estimated Number of 

Airports 

Percentage of 

Airports 

Stormwater drainage system 211 63 

Containment pond/basin 121 36 

Aboveground/underground Tank 57 17 

Glycol recovery vehicles/sweepers 54 16 

Other (vegetated swales, snow melters, absorbant) 34 10 

Plug and pump 29 9 

Source: EPA airport questionnaire database (Scaled to national estimate) (USEPA, 2008c). 

 EPA estimates that approximately half (46 percent) of the U.S. airports with deicing 

operations also operate systems to treat or recover their deicing stormwater. The treatment and 

recovery technologies reported by airports include equalization (46 percent), oil/water separation 

(5 percent), sand or other media filtration (4 percent), membrane separation (1 percent), and 

biological treatment (1 percent). Airports reporting other types of treatment technologies 

comprise 8 percent of the population, including mechanical vapor recompression (MVR), 

aeration, and distillation. These technologies are described in detail in Section 9. 

5.3 References

USDOT. 2008a. Report to Congress: National Plan of Integrated Airport Systems (NPIAS) 

2009-2013. U.S. Department of Transportation, Federal Aviation Administration. Washington, 

D.C. http://www.faa.gov/airports_airtraffic/airports/planning_capacity/npias/reports/ 

USDOT. 2008b. FAA Regional Offices. U.S. Department of Transportation, Federal Aviation 

Administration. Washington, D.C. 

www.faa.gov/about/office_org/headquarters_offices/arp/regional_offices/ 

USEPA. 2008a. Airline Screener Deicing Questionnaire Database. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. DCN AD00937. 

USEPA. 2008b. Airline Detailed Deicing Questionnaire Database. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. DCN AD00938. 

USEPA. 2008c. Airport Deicing Questionnaire Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD00927. 

USEPA. 2000. Preliminary Data Summary: Airport Deicing Operations. EPA-821-R-00-016, 

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. 

http://www.epa.gov/guide/airport . DCN AD00005 

USEPA. 2005. Supporting Statement: Survey of Airport Deicing Operations. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. DCN AD00447. 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

July 2009 6-1 

6. DEICING CHEMICAL USE AND DEICING STORMWATER CHARACTERIZATION

 This section summarizes EPA’s estimate of the amount of airfield and aircraft 

deicing/anti-icing chemicals currently in use by U.S. commercial airports and provides 

information on deicing stormwater pollutant characteristics to the extent possible. Deicing 

stormwater discharges are “weather-dependent” and they are, by nature, highly variable. In 

addition, deicing chemical disposition after its intended use is not fully understood. These 

chemicals may be lost to evaporation, dispersion, or soil absorption; collected; or released into 

the environment and discharged from the airport. Limited information is currently available on 

each of these disposition methods. This section presents the information EPA has collected on 

the types of pollutants present in deicing stormwater and their ranges of concentrations. 

6.1 Deicing Chemical Usage

 As discussed in Section 5, several deicing chemicals are commonly used at U.S. 

commercial airports. These chemicals are used for either airfield or aircraft deicing/anti-icing 

and their usages are described below. 

6.1.1 Airfield Chemical Use 

 Pavement deicing/anti-icing removes or prevents frost, snow, or ice from accumulating 

on runways, taxiways, aprons, gates, and ramps. Airports use mechanical and chemical methods 

for this purpose, more often using mechanical methods. Because ice, sleet, and snow may be 

difficult to remove by mechanical methods alone, many airports also use sand and/or chemical 

deicing agents such as potassium acetate, sodium acetate, sodium formate, glycol-based 

products, or urea. Based on the data collected by EPA in the 2006 Airport Deicing Questionnaire 

(airport questionnaire), the most common airfield deicing chemical currently used by U.S. 

airports is potassium acetate (approximately 64 percent of airfield chemical usage by weight). In 

addition, there is a trend by U.S. airports to cease or decrease their use of urea for airfield deicing 

due to concerns with water quality impacts from its discharge. 

 Table 6-1 lists total airfield chemical usage as reported by the 150 U.S. airports that 

responded to the airport questionnaire for the 2002/2003, 2003/2004, and 2004/2005 deicing 

seasons. Ninety airports reported use of airfield deicing chemicals, approximately thirty eight 

airports reported no airfield deicing (including no sand use), while the remainder reported only 

sand use or unknown chemical use. 
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Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

July 2009 6-2 

Table 6-1. Surveyed U.S. Commercial Airports - Airfield Chemical Usage 

Chemical 

2002/2003 Total 

Airport Usage 

(tons/year) 

2003/2004 Total 

Airport Usage 

(tons/year) 

2004/2005 Total 

Airport Usage 

(tons/year) 

Average Total 

Airport Usage 

(tons/year) 

Percentage of 

Chemical 

Usage 

Potassium acetate 22,804 20,267 20,029 21,292 64 

Propylene glycolbased fluids 3,317 4,147 2,884 3,870 12 

Airside urea 3,015 3,804 4,031 3,553 11 

Sodium acetate 2,815 3,195 2,663 3,072 9 

Sodium formate 1,663 696 1,359 1,064 3 

Ethylene glycolbased fluids 1,038 465 691 656 2 

Source: EPA Airport Questionnaire, 2002-2005 deicing seasons (USEPA, 2008a). 

Note: This table is based on data from 90 airports that reported airfield deicing chemical usage. The three-year 

average is not a straight average of the total annual amounts; the average for each airport was evaluated and 

calculated separately. 

 Using EPA’s survey statistical weighting factors, the total usage by chemical can be 

scaled up to estimate a national airfield chemical usage for all commercial U.S. airports (see 

Table 6-2). 

Table 6-2. U.S. Commercial Airports - National Estimate of Airfield Chemical Usage 

Chemical 

Estimated Total Airport Usage 

(tons/year) 

Percentage of 

Chemical Usage 

Potassium acetate 22,538 63 

Propylene glycol-based fluids 3,883 11 

Airside urea 4,127 12 

Sodium acetate 3,100 9 

Sodium formate 1,117 3 

Ethylene glycol-based fluids 774 2 

6.1.2 Aircraft Chemical Use and Purchasing Patterns 

 There are four types of aircraft deicing fluids (ADFs) manufactured around the world, 

referred to by the aviation and chemical industries as Types I through IV. Of these, Type I and 

Type IV are commonly used at U.S. commercial airports. Type I ADF is used to defrost and 

deice aircraft and Type IV ADF is used to prevent icing from reoccurring (anti-icing) after initial 

deicing with a Type I ADF. ADFs contain a primary freezing point depressant (typically 

propylene glycol (PG) or ethylene glycol (EG)) and other additives. ADFs work by adhering to 

aircraft surfaces to remove and/or prevent snow and ice accumulation by virtue of their 

depressed freezing points. Airports conduct two types of deicing: dry weather deicing to remove 

frost and wet weather deicing and anti-icing during precipitation such as snow, sleet (ice pellets), 

or freezing rain. Airports may also perform dry weather deicing on some types of aircraft whose 

fuel tanks become super-cooled during high-altitude flight, resulting in formation of frost/ice on 

aircraft wings at lower altitudes and after landing. Based on the data collected by EPA in the 

2006 Airline Deicing Questionnaire (airline questionnaire), the most common ADF is Type I 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

July 2009 6-3 

PG-based fluids (approximately 77 percent of ADF usage/purchase). In addition, U.S. airports 

have been trending towards greater use of PG-based fluids and less use of EG-based fluids. 

 Table 6-3 presents a national estimate of the average aircraft chemical usage/purchase by 

U.S. commercial airports by type of fluid. 

Table 6-3. U.S. Commercial Airports – National Estimate of Aircraft Chemical 

Usage/Purchase 1

Chemical 

Average Total Airport 

Usage/Purchase 

(million gallons/year) 2 Percentage of Chemical Usage 

Type I PG ADF 19.305 77.1 

Type IV PG ADF 2.856 11.4 

Type I EG ADF 2.575 10.3 

Type IV EG ADF 0.306 1.2 

Sources: EPA Airline Questionnaire (USEPA, 2008b); Airport Deicing Loadings Database (USEPA, 2008c). 

1 EPA used the ADF purchase information to represent usage, per airline industry recommendations. 

2 Total gallons normalized to 100% PG/EG. 

6.2 Deicing Stormwater Characterization

 EPA evaluated data from a variety of sources to better understand the components of 

deicing chemicals and ADFs that end up in deicing stormwater. These data include information 

on the additives included in ADFs, data collected during sampling of concentrated and diluted 

ADFs used at the Detroit Metropolitan Wayne County (DTW) and Minneapolis/St. Paul 

International (MSP) airports during the 2003/2004 deicing season, data collected during 

sampling of deicing stormwater at the Albany International (ALB), Pittsburgh International 

(PIT), Denver International (DIA), and Greater Rockford (RFD) airports during the 2004/2005 

deicing season, current data for airports included in the PCS database, and deicing stormwater 

data collected by EPA during the Preliminary Data Study, through site visits, or through industry 

or permit authority submissions. Section 8 summarizes the types of pollutants found in deicing 

stormwater based on these sources. 

6.2.1 Airfield Deicing Chemicals and Associated Deicing Stormwater 

 Most solid airfield deicing chemical products are composed of a freezing point depressant 

(e.g., potassium acetate, sodium acetate) and minimal additives (e.g., corrosion inhibitors). 

Liquid airfield deicing chemical products are composed of a freezing point depressant (e.g., 

potassium acetate, propylene glycol), water, and minimal additives. The airfield deicing products 

that include salts (i.e., potassium acetate, sodium acetate, and sodium formate) will all ionize in 

water, creating positive salt ions (K+

, Na+) and BOD load as the acetate or formate ion degrades 

into carbon dioxide (CO2) and water. 

 Urea is typically applied to pavement and runway areas in granular form. Urea degrades 

by hydrolysis to CO2 and ammonia, which can be toxic to aquatic organisms even at very low 

concentrations. Once ammonia is formed, it either remains in solution as ammonia or its ionized 

form (NH4

+

), biologically converts to other nitrogen forms (e.g., NO3 or N2), or volatilizes to the 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

July 2009 6-4 

air. The formation of ammonia is dependent on the pH and temperature of the receiving water. 

The higher the pH and temperature, the more ammonia is formed. Another potentially toxic 

byproduct of urea degradation is nitrous acid, which reacts with secondary amines to form 

nitrosamines, many of which are known carcinogens. 

 EPA has limited data on airfield deicing stormwater that do not also contain aircraft 

deicing area stormwater. Most of EPA’s stormwater data include both airfield and aircraft 

deicing components. However, during sampling at Detroit Metro, EPA collected samples from 

the airport’s runway and open area ponds (Pond 3 East and Pond 6). These ponds do not contain 

aircraft deicing area stormwater since a separate pond collects runoff from the gate and deicing 

pad areas where the stormwater is expected to contain ADF. Detroit sometimes uses sand and 

potassium acetate for runway traction and deicing in addition to their usual mechanical snow 

removal equipment. It does not use urea-based deicers. Table 6-4 presents the sampling data 

from the two airfield/open area runoff ponds. 

6.2.2 Aircraft Deicing Chemicals and Associated Deicing Stormwater 

 ADFs contain a primary freezing point depressant (typically PG or EG) and additives. 

Typical additives are thickening agents, wetting agents, corrosion inhibitors, buffer, and dye, 

which make up 1 to 4 percent of the fluid mass. Type IV fluids have higher concentrations of the 

freezing point depressant and greater viscosity so that the fluid stays on the aircraft until take-off. 

 The actual composition of ADFs varies and information on specific additive compounds 

is usually considered proprietary by ADF manufacturers. EPA believes that typical ADFs most 

likely include the following components: 

ADF Component Composition (%) 

Propylene glycol or ethylene glycol 50-88 

Surfactant/wetting agent About 0.5 

Corrosion inhibitor/flame retardant About 0.5 

pH buffer About 0.25 

Dyes <1 

Water Remainder 

Source: Environmental Impact and Benefit Assessment for Proposed Effluent Limitation Guidelines and Standards 

for the Airport Deicing Category (USEPA. 2009) 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

Source: Final Sampling Episode Report Detroit Metropolitan Wayne County International Airport (DTW) (USEPA, 

2006a). 

1 Pollutant listed by EPA as a priority pollutant. See 40 CFR Part 423, Appendix A. 

2 Number following analyte name refers to analytical method. 1671 is a Clean Water Act method (USEPA, 1998) 

and 8015D is a hazardous waste method promulgated under the Resource Conservation and Recovery Act (RCRA) 

(USEPA, 2003). 

ND – Not detected (number in parentheses is reporting limit). 

July 2009 6-5 

Table 6-4. EPA’s Analytical Results for Pond 3E Effluent and Pond 6 Effluent, DTW 

Analyte Unit Pond 3 East Effluent Pond 6 Effluent 

5-Day Biochemical Oxygen Demand (BOD5) mg/L 146 43.0 

Chloride mg/L 855 315 

Chemical Oxygen Demand (COD) mg/L 273 111 

Nitrate/Nitrite (NO2 + NO3-N) mg/L 0.0400 0.110 

Sulfate mg/L 50.1 51.0 

Total Dissolved Solids (TDS) mg/L 1,790 833 

Total Kjeldahl Nitrogen (TKN) mg/L 1.51 0.990 

Total Organic Carbon mg/L 813 314 

Total Phosphorus mg/L 0.340 0.280 

Total Suspended Solids (TSS) mg/L 150 149 

Aluminum μg/L 1,660 2,110 

Aluminum, Dissolved μg/L ND (50.0) 64.5 

Barium μg/L 92.3 81.8 

Barium, Dissolved μg/L 77.5 66.5 

Calcium μg/L 96,600 69,400 

Calcium, Dissolved μg/L 91,000 63,500 

Chromium 1 μg/L ND (10.0) ND (10.0) 

Copper 1 μg/L ND (10.0) ND (10.0) 

Iron μg/L 3,630 4,390 

Iron, Dissolved μg/L 407 600 

Magnesium μg/L 20,300 17,400 

Magnesium, Dissolved μg/L 18,200 15,700 

Manganese μg/L 508 411 

Manganese, Dissolved μg/L 462 335 

Molybdenum μg/L ND (10.0) ND (10.0) 

Molybdenum, Dissolved μg/L ND (10.0) ND (10.0) 

Sodium μg/L 547,000 191,000 

Sodium, Dissolved μg/L 522,000 189,000 

Titanium μg/L 26.2 34.8 

Zinc 1 μg/L 41.4 43.8 

Acetone μg/L ND (50.0) ND (50.0) 

Propylene Glycol - 1671 2 mg/L ND (10.0) ND (10.0) 

Propylene Glycol - 8015D 2 mg/L ND (10.0) ND (10.0) 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

July 2009 6-6 

 Despite limited public information, EPA has identified three main classes of additives 

widely used among ADF manufacturers. Benzotriazole (BT) and methyl-substituted 

benzotriazole (MeBT) are corrosion inhibitor/flame retardants that reduce flammability from 

corrosion of metal components carrying a direct current. Alkylphenol/alkylphenol ethoxylates 

(AP/APEO) are nonionic surfactants widely used to reduce surface tension in aircraft deicers. 

Finally, triethanolamine is a pH buffer. (See Aircraft Deicing and Anti-icing Fluids Fate, 

Transport and Environmental Impacts (ERG, 2007). EPA also has information indicating that 

high molecular weight, nonlinear polymers may be used as thickening agents in ADFs (see 

Aircraft Deicing Fluids (ERG, 2007b) and various classes of dyes can be used to color the ADF. 

The classes of dyes identified as potentially used in ADFs include azo, xanthene, triphenyl 

methane, and anthroquinone dyes (see Questions Regarding Pylam Dye Use in ADF (ERG, 

2007a). 

 Analyses conducted by U.S. Geological Survey (USGS) at General Mitchell International 

airport in Milwaukee, WI, and EPA’s sampling programs, have confirmed the presence of 

glycols, triazole compounds, and alkylphenol compounds in deicing stormwater. EPA collected 

deicing stormwater samples at MSP and DTW during the 2004/2005 winter season. At MSP, 

EPA collected samples of deicing stormwater from segregated high concentration and low 

concentration storage tanks. At DTW, Northwest collected its deicing stormwater from a 

March 24, 2005 deicing event into a portable “frac” tank, which was then sampled by EPA. 

Table 6-5 lists the constituents detected in these deicing stormwaters and their concentrations. 

During the 2005/2006 deicing season, EPA collected five consecutive days of samples of 

influent to and effluent from deicing stormwater treatment at ALB, PIT, DEN, and RFD. The 

sampled deicing stormwater at these airports, prior to treatment, shows a wide range of 

constituents and constituent concentrations between the airports, as shown in Tables 6-6 and 6-7. 

Where, the five day average for each pollutant at DEN, PIT, and ALB are used for comparison 

between the airports. 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

Sources: Final Sampling Episode Report Minneapolis/St. Paul International Airport (MSP) (USEPA, 2006b); Final 

Sampling Episode Report Detroit Metropolitan Wayne County International Airport (DTW) (USEPA, 2006a). 1 Pollutant listed by EPA as a priority pollutant. See 40 CFR Part 423, Appendix A. 

EXCLUDE – Data excluded from the data set (see data review narratives in Appendix C for details). 

< – Average result includes at least one nondetect value. 

ND – Not detected (number in parenthesis is reporting limit). 

July 2009 6-7 

Table 6-5. MSP and DTW Grab Sample Data Summary for Collected Deicing Stormwater 

Analyte Unit

MSP 

High 

Concentration 

Storage Tank

MSP 

Low 

Concentration 

Storage Tank

DTW 

Northwest Frac 

Tank 

Classical Pollutants

Ammonia as Nitrogen (NH3-N) mg/L ND (0.05) ND (0.05) 0.790 

BOD5 mg/L 115,000 8,000 140,000 

Chloride mg/L 45.0 27.0 25.0 

COD mg/L 358,000 16,000 332,000 

Hexane Extractable Material (HEM) mg/L 50.0 ND (5.00) 22.0 

Nitrate/Nitrite (NO2 + NO3-N) mg/L 0.0950 <0.0600 0.240 

Silica Gel Treated HEM (SGT-HEM) mg/L 17.0 ND (5.00) ND (6.00) 

Sulfate mg/L 21.2 13.6 20.3 

TDS mg/L 1,370 559 1,440 

TKN mg/L 13.5 5.61 71.1 

Total Organic Carbon mg/L 96,100 5,660 93,100 

Total Phosphorus mg/L 6.49 < 2.10 0.320 

Total Recoverable Phenolics mg/L 0.150 0.0375 < 0.007 

TSS mg/L 89.0 19.5 11.5 

Total and Dissolved Metals

Aluminum μg/L 525 508 ND (500) 

Aluminum, Dissolved μg/L ND (500) 136 ND (500) 

Antimony, Dissolved 1 μg/L 201 ND (20.0) ND (200) 

Barium μg/L 114 67.1 52.4 

Barium, Dissolved μg/L 36.4 61.9 46.9 

Calcium μg/L 68,200 35,200 127,000 

Calcium, Dissolved μg/L 59,600 34,500 125,000 

Copper 1 μg/L ND (100) 37.6 ND (100) 

Copper, Dissolved 1 μg/L ND (100) 16.4 ND (100) 

Iron μg/L 11,000 7,470 1,410 

Iron, Dissolved μg/L 4,960 6,030 1,370 

Magnesium μg/L 9,230 4,250 12,900 

Magnesium, Dissolved μg/L 8,490 4,080 13,000 

Manganese μg/L 887 317 433 

Manganese, Dissolved μg/L 756 308 423 

Mercury 1 μg/L ND (40) ND (2) 45.1 

Mercury, Dissolved 1 μg/L ND (40) ND (2) 68.7 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

Table 6-5 (Continued) 

Sources: Final Sampling Episode Report Minneapolis/St. Paul International Airport (MSP) (USEPA, 2006b); Final 

Sampling Episode Report Detroit Metropolitan Wayne County International Airport (DTW) (USEPA, 2006a). 1 Pollutant designated by EPA as a priority pollutant in 40 CFR Part 423. 

2 Number following analyte name refers to analytical method. 1671 is a Clean Water Act method (USEPA, 1998) 

and 8015D is a hazardous waste method promulgated under the Resource Conservation and Recovery Act (RCRA) 

(USEPA, 2003). 

EXCLUDE – Data excluded from the data set (see data review narratives in Appendix C for details). 

< – Average result includes at least one nondetect value. 

ND – Not detected (number in parenthesis is reporting limit). 

July 2009 6-8 

Analyte Unit

MSP 

High 

Concentration 

Storage Tank

MSP 

Low 

Concentration 

Storage Tank

DTW 

Northwest Frac 

Tank 

Molybdenum μg/L 19,100 794 15,900 

Molybdenum, Dissolved μg/L 19,000 771 16,000 

Sodium μg/L 48,700 18,700 22,800 

Sodium, Dissolved μg/L 48,100 18,600 19,200 

Tin μg/L 611 32.1 673 

Tin, Dissolved μg/L 616 32.5 646 

Titanium μg/L ND (100) 13.5 ND (100) 

Zinc 1 μg/L 492 291 119 

Zinc, Dissolved 1 μg/L 444 277 119 

Volatile and Semivolatile Organics

Acetone μg/L 1,440 23,700 3,340 

Propylene Glycol – 1671 2 mg/L — — 192,000 

Propylene Glycol – 8015D 2 mg/L 193,000 8,600 170,000 

Trichloroethene 1 μg/L ND (10) ND (10) 14.5 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

Sources: Draft Sampling Episode Report Denver International Airport (USEPA, 2006c); Draft Sampling Episode 

Report Pittsburgh International Airport (USEPA, 2006d); Draft Sampling Episode Report Albany International 

Airport (USEPA, 2006e). 

ND – Not detected (number in parentheses is reporting limit). 

NC – Not collected. 

July 2009 6-9 

Table 6-6. DEN, PIT, and ALB - 5-Day Average Data Summary for Untreated Deicing 

Stormwater 

Analyte Units

DEN Airport Effluent 

from Equalization 

Feed Tank 

5-day Average

PIT Airport 

Influent to RO 

Unit 

5-day Average

ALB Airport Influent to 

Anaerobic Treatment 

System 

5-day Average

Alkalinity mg/L 706 481 159 

Ammonia As Nitrogen (NH3-N) mg/L 0.448 ND (0.05) <0.262 

BOD5 mg/L 149,000 16,600 3,400 

COD mg/L 247,000 28,300 5,350 

Chloride mg/L 120 11.6 90.0 

Hardness mg/L 362 542 248 

HEM mg/L 9.20 ND (6.0) ND (5.0) 

Nitrate/Nitrite (NO3-N + NO2-N) mg/L 0.0266 <0.0204 <0.0284 

Sulfate mg/L 60.0 48.1 26.4 

TDS mg/L NC 1,670 650 

TKN mg/L 6.41 9.04 1.61 

Total Organic Carbon (TOC) mg/L 89,000 7,720 1,570 

Total Orthophosphate mg/L <1.03 <0.0196 0.115 

Total Phosphorus mg/L <2.76 0.0778 0.946 

Total Recoverable Phenolics mg/L 0.0608 0.0187 ND (0.005) 

TSS mg/L <17.8 <8.40 16.6 

Arsenic μg/L <81.8 12.7 ND (10) 

Barium μg/L <13.2 103 42.5 

Boron μg/L <723 532 ND (100) 

Calcium μg/L 103,000 155,000 48,300 

Copper μg/L 305 ND (10) ND (10) 

Iron μg/L 1,210 5,870 6,270 

Magnesium μg/L 5,360 6,260 9,990 

Manganese μg/L 156 532 736 

Molybdenum μg/L 11,900 ND (10) ND (10) 

Selenium μg/L 172 31.8 <5.38 

Sodium μg/L 254,000 54,300 89,600 

Tin μg/L <258 41.0 ND (30) 

Zinc μg/L <81.1 71.8 48.3 

Acetone μg/L 4,100 10,900 15,400 

Benzoic Acid μg/L 716 ND (50) 278 

Methyl Ethyl Ketone μg/L ND (50) ND (50) <58.5 

Phenol μg/L ND (100) ND (100) 24.5 

Ethylene Glycol - 1671 1 mg/L <167 <65.6 ND (10) 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

Table 6-6 (Continued) 

Sources: Draft Sampling Episode Report Denver International Airport (USEPA, 2006c); Draft Sampling Episode 

Report Pittsburgh International Airport (USEPA, 2006d); Draft Sampling Episode Report Albany International 

Airport (USEPA, 2006e). 

ND – Not detected (number in parentheses is reporting limit). 

1 Number following analyte name refers to analytical method. 1671 is a Clean Water Act method (USEPA, 1998) 

and 8015D is a hazardous waste method promulgated under the Resource Conservation and Recovery Act (RCRA) 

(USEPA, 2003). 

July 2009 6-10 

Analyte Units

DEN Airport Effluent 

from Equalization 

Feed Tank 

5-day Average

PIT Airport 

Influent to RO 

Unit 

5-day Average

ALB Airport Influent to 

Anaerobic Treatment 

System 

5-day Average

Ethylene Glycol - 8015D 1 mg/L <172 <73.6 ND (10) 

Propylene Glycol - 1671 1 mg/L 174,000 15,700 2,570 

Propylene Glycol - 8015D 1 mg/L 173,000 15,900 2,630 

Tolyltriazole μg/L 10,100 7,860 325 

Nonylphenol, total μg/L ND (5.0) 22.2 ND (12.0) 

Nonylphenol-1-Ethoxylate μg/L ND (7.4) 130 ND (19.0) 

Nonylphenol-2-Ethoxylate μg/L ND (21.0) 190 ND (53.0) 

Nonylphenol-3-Ethoxylate μg/L 17.8 59.9 3.90 

Nonylphenol-4-Ethoxylate μg/L 16.4 15.4 3.01 

Nonylphenol-5-Ethoxylate μg/L 21.5 213 5.70 

Nonylphenol-6-Ethoxylate μg/L 50.4 403 12.5 

Nonylphenol-7-Ethoxylate μg/L 60.7 619 15.4 

Nonylphenol-8-Ethoxylate μg/L 86.2 841 24.7 

Nonylphenol-9-Ethoxylate μg/L 79.1 942 24.7 

Nonylphenol-10-Ethoxylate μg/L 92.5 1,050 38.1 

Nonylphenol-11-Ethoxylate μg/L 100 1,040 40.4 

Nonylphenol-12-Ethoxylate μg/L 216 833 33.7 

Nonylphenol-13-Ethoxylate μg/L 167 589 25.2 

Nonylphenol-14-Ethoxylate μg/L 116 386 17.8 

Nonylphenol-15-Ethoxylate μg/L 69.9 222 8.80 

Nonylphenol-16-Ethoxylate μg/L 43.4 107 4.69 

Nonylphenol-17-Ethoxylate μg/L 23.3 53.5 2.27 

Nonylphenol-18-Ethoxylate μg/L 12.4 23.3 1.09 

Octylphenol μg/L <8.80 ND (0.01) ND (2.00) 

Octylphenol-2-Ethoxylate μg/L 71.8 ND (0.144) 0.159 

Octylphenol-3-Ethoxylate μg/L 1,460 4.38 2.66 

Octylphenol-4-Ethoxylate μg/L 1,260 ND (2.26) ND (2.26) 

Octylphenol-5-Ethoxylate μg/L 891 ND (2.93) ND (2.93) 

Octylphenol-6-Ethoxylate μg/L 441 ND (2.69) ND (2.69) 

Octylphenol-7-Ethoxylate μg/L 198 ND (2.58) ND (2.58) 

Octylphenol-8-Ethoxylate μg/L 116 ND (1.85) ND (1.85) 

Octylphenol-9-Ethoxylate μg/L 44.6 ND (0.636) ND (0.636) 

Octylphenol-10-Ethoxylate μg/L 22.5 ND (0.636) ND (0.636) 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

Table 6-6 (Continued) 

Sources: Draft Sampling Episode Report Denver International Airport (USEPA, 2006c); Draft Sampling Episode 

Report Pittsburgh International Airport (USEPA, 2006d); Draft Sampling Episode Report Albany International 

Airport (USEPA, 2006e). 

ND – Not detected (number in parentheses is reporting limit). 

1 Number following analyte name refers to analytical method. 1671 is a Clean Water Act method (USEPA, 1998) 

and 8015D is a hazardous waste method promulgated under the Resource Conservation and Recovery Act (RCRA) 

(USEPA, 2003). 

July 2009 6-11 

Analyte Units

DEN Airport Effluent 

from Equalization 

Feed Tank 

5-day Average

PIT Airport 

Influent to RO 

Unit 

5-day Average

ALB Airport Influent to 

Anaerobic Treatment 

System 

5-day Average

Octylphenol-11-Ethoxylate μg/L 12.0 ND (0.267) ND (0.267) 

Octylphenol-12-Ethoxylate μg/L 8.08 ND (0.113) ND (0.113) 

Total Nonylphenol-3-EthoxylateNonlyphenol-18- μg/L 1,170 7,400 260 

Total Octylphenol-2-EthoxylateOctylphenol-12-Ethoxylate μg/L 4,530 ND (16.0) ND (16.0) 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

Source: Draft Sampling Episode Report Greater Rockford Airport, Sampling Episode 6529 April 20, 2006 and 

Sampling Episode 6530 August 29, 2006 (USEPA, 2006f). 

ND – Not detected (number in parentheses is reporting limit). 

NC – Not collected. 

 1 Number following analyte name refers to analytical method. 1671 is a Clean Water Act method (USEPA, 1998) 

and 8015D is a hazardous waste method promulgated under the Resource Conservation and Recovery Act (RCRA) 

(USEPA, 2003). 

July 2009 6-12 

Table 6-7. RFD - 1-Day Data Summary for Untreated Deicing Stormwater 

Analyte Units

Influent to Aerobic Treatment 

System, Spring 

Alkalinity mg/L 1,030 

Ammonia As Nitrogen (NH3-N) mg/L 59.6 

BOD5 mg/L 603 

COD mg/L 646 

Chloride mg/L 14.0 

Hardness mg/L 112 

Nitrate/Nitrite (NO3-N + NO2-N) mg/L 0.0190 

Sulfate mg/L 5.65 

TDS mg/L 384 

TKN mg/L 82.8 

TOC mg/L 137 

Total Phosphorus mg/L 0.330 

TSS mg/L 85.0 

Barium μg/L 20.3 

Calcium μg/L 6,600 

Iron μg/L 108 

Magnesium μg/L 14,700 

Manganese μg/L 164 

Sodium μg/L 4,790 

Acetone μg/L 86.6 

Methyl Ethyl Ketone μg/L 136 

Propylene Glycol - 8015D 1 mg/L 31.0 

Tolyltriazole μg/L 45.3 

Bisphenol A ng/L ND (12,000) 

N-Nonylphenol-2-Ethoxylate NC 50.0 

N-Nonylphenoxyl-2-Carboxylic Acid NC 41.0 

Octylphenol-9-Ethoxylate μg/L ND (3.18) 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

July 2009 6-13 

6.3 References

USEPA. 1998. Method 1671: Volatile Organic Compounds Specific to the Pharmaceutical 

Manufacturing Industry by Gas Chromatography/Flame Ionization Detector. U.S. 

Environmental Protection Agency/Office of Water. Washington, D.C. 

http://www.epa.gov/waterscience/methods/method/files/1671.pdf 

USEPA. 2003. Method 8015D: Nonhalogenated Organics Using Gas Chromatography/Flame 

Ionization Detector. (From “Test Methods for Evaluating Solid Waste, Physical/Chemical 

Methods,” publication no. SW-846.) U.S. Environmental Protection Agency/Office of Solid 

Waste. Washington, D.C. http://www.epa.gov/epawaste/hazard/testmethods/pdfs/8015d_r4.pdf 

 

USEPA. 2008a. Airport Questionnaire Database. U.S. Environmental Protection Agency/Office 

of Water. Washington, D.C. DCN AD00927. 

USEPA. 2008b. Airline Questionnaire Database. U.S. Environmental Protection Agency/Office 

of Water. Washington, D.C. DCN AD00938. 

USEPA. 2008c. Airport Deicing Loadings Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD00857. 

USEPA. 2009. Environmental Impact and Benefit Assessment for Proposed Effluent Limitation 

Guidelines and Standards for the Airport Deicing Category. EPA 821-R-09-003. (July). DCN 

AD01197. 

USEPA. 2006a. Final Sampling Episode Report Detroit Metropolitan Wayne County 

International Airport (DTW), Episode 6508. U.S. Environmental Protection Agency/Office of 

Water. Washington, D.C. (July 12). DCN AD00620. 

USEPA. 2006b. Final Sampling Episode Report Minneapolis/St. Paul International Airport 

(MSP), Episode 6509. U.S. Environmental Protection Agency/Office of Water. Washington, 

D.C. (July 12). DCN AD00622. 

USEPA. 2006c. Final Sampling Episode Report Denver International Airport, Episode 6522.

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. (August 2). DCN 

AD00840. 

USEPA. 2006d. Final Sampling Episode Report Pittsburgh International Airport, Episode 6528.

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. (November 1). DCN 

AD00841. 

USEPA. 2006e. Final Sampling Episode Report Albany International Airport, Episode 6523.

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. (July 19). DCN 

AD00842. 

USEPA. 2006f. Final Sampling Episode Report Greater Rockford Airport, Sampling Episode 

6529 (April 20, 2006) and Sampling Episode 6530 (August 29, 2006, January 18, 2008). U.S. 

Environmental Protection Agency/Office of Water. Washington, D.C. DCN AD00839. 
Technical Development Document for Proposed Effluent 6. Deicing Chemical Use and 

Limitation Guidelines and Standards for the Airport Deicing Category Deicing Stormwater Characterization 

July 2009 6-14 

ERG. 2007a. Personal communication (telecon) between Mary Willett (ERG) and Bob Reynolds 

(Pylam Dyes). Questions Regarding Pylam Dye Use in ADF. (April 16). DCN AD00686. 

ERG. 2007b. Personal communication (telecon) between Mary Willett (ERG) and Jeffery Carey 

(Noveon). Aircraft Deicing Fluids. (April 16). DCN AD00688. 

Corsi, SR et al. 2003. Nonylphenol Ethoxylates and Other Additives in Aircraft Deicers, Antiicers, and Waters Receiving Airport Runoff. (January 1). DCN AD00083.
Technical Development Document for Proposed Effluent 7. Pollutants of Concern 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 7-1 

7. POLLUTANTS OF CONCERN

 EPA identified pollutants in stormwater associated with deicing activities that should 

potentially be controlled. Pollutants of concern may include pollutants directly associated with 

deicing chemicals, by-products from deicing activities (e.g. metals), and/or pollutant parameters 

that are influenced by deicing chemicals (e.g., BOD and COD). 

 EPA reviewed its deicing stormwater sampling data as well as the information available 

through NPDES permits to identify conventional, nonconventional, and priority pollutants 

present in airport deicing stormwater and evaluate whether they are causing environmental 

impacts from their discharge. This section presents the results of EPA’s evaluation and identifies 

potential pollutants of concern and those proposed for regulation. 

7.1 Identification of Airport Deicing/Anti-icing Stormwater Pollutants

 Airport deicing stormwater is generated when airfield chemicals and aircraft deicing/antiicing fluids (ADFs) mix with stormwater (either directly or as a result of snowmelt). Because 

deicing stormwater is weather-dependent, it is highly variable in nature and pollutant 

concentrations may vary greatly. In addition, other airport-related activities, including aircraft 

fueling and maintenance activities, may contribute pollutants to stormwater that is also 

contaminated with deicing chemicals. Because of the inherent difficulties in characterizing 

deicing stormwater, EPA evaluated pollutants detected in deicing stormwater, pollutants present 

in source water, and pollutants that are present in ADFs prior to use to determine the pollutants 

likely to be present in deicing stormwater. 

 EPA considered multiple sources of information to identify potential pollutants of 

concern in deicing stormwater including the following: 

• EPA sampling data from the Preliminary Data Summary; 

• NPDES permits for airports to determine pollutants that are currently monitored 

or limited at airports; 

• EPA sampling data collected during the 2004/2005 and 2005/2006 deicing 

seasons to identify pollutants present in untreated deicing stormwater; 

• EPA sampling data collected during the 2004/2005 and 2005/2006 deicing 

seasons to determine pollutants present in source water; and 

• EPA sampling data collected during the 2004/2005 deicing season, current 

research, and expert sources to determine ADF constituents. 

EPA also looked at toxic weighting factors to assess the comparative toxicity of different 

pollutants. Each of these data sources is discussed below. 

Airport Deicing Operations PDS 

 For the PDS, EPA sampled: 

• Type I ADFs; 

• Lagoon stormwater from Albany International Airport; 

• Untreated deicing stormwater from Kansas City International Airport; 

• Untreated deicing stormwater from Bradley International Airport; 
Technical Development Document for Proposed Effluent 7. Pollutants of Concern 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 7-2 

• Untreated deicing stormwater from Greater Rockford Airport; and 

• Stormwater outfalls from Bradley International Airport. 

The pollutants detected in one or more of these samples were summarized in Table 8-4 of the 

Preliminary Data Summary: Airport Deicing Operations report (USEPA, 2000) and are 

presented in Table 7-1 of this report. 

NPDES Permits 

 EPA reviewed NPDES individual and general stormwater permits for airports that are 

estimated to have the most deicing operations in the United States. The permit review is 

summarized in the Airport Deicing Operations NPDES Permit Review Summary memorandum 

(ERG, 2007a). Table 7-1 lists pollutants that have monitoring and limit requirements in current 

airport NPDES permits. 

Pollutants Present in Untreated Deicing Stormwater 

 Under the current rulemaking effort, EPA collected samples at the following six airports 

during the 2004/2005 and 2005/2006 deicing seasons: 

• Detroit Metropolitan Wayne County (DTW) airport; 

• Minneapolis-St. Paul International (MSP) airport; 

• Albany International (ALB) airport; 

• Greater Rockford (RFD) airport; 

• Pittsburgh International (PIT) airport; and 

• Denver International (DEN) airport. 

Table 7-1 lists pollutants detected in untreated deicing stormwater from these locations. 

Pollutants Present in Source Water 

 Table 7-1 also lists pollutants detected in source water samples at the airports EPA 

sampled at during the 2004/2005 and 2005/2006 deicing seasons. 

Deicing/Anti-Icing Fluid Constituents 

 EPA does not have sufficient information on all of the constituents of airfield chemicals 

and ADFs to fully characterize them for Table 7-1. However, EPA’s airport questionnaire does 

identify which chemicals and brand-name products are commonly used, which can help to define 

the pollutants expected to be in deicing stormwater. 
7-3 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 1 TWF assumed to be equal to 2.8 for any of the alkylphenol ethoxylates. 

Note: Octylphenol and nonylphenol should have a higher toxicity than the alkylphenol ethoxylates. July 2009 

Table 7-1. Pollutants Under Consideration as Potential Pollutants of Concern 

Analyte

Pollutants 

Identified in 

the PDS 

Sampling 

Pollutants 

Monitored in 

NPDES 

Permits 

Pollutants Identified 

in Raw ADF in 

Research or 2004-

2006 EPA Sampling 

Pollutants Identified 

in Untreated 

Stormwater in 2004-

2006 EPA Sampling 

Pollutants Ident

in Source Wate

2004-2006 EP

Sampling 

Classicals Alkalinity X X Ammonia As Nitrogen (NH3-N) X X X X 5-Day Biochemical Oxygen Demand (BOD5) 

X X X X 

Chemical Oxygen Demand (COD) 

X X X 

Chloride X X X Dissolved Oxygen X Hardness X X Oil & Grease X  Silica-Gel Treated  Hexane Extractable Material 

(SGT-HEM) 

X X 

 Hexane Extractable Material 

(HEM) 

X X X 

Nitrate/Nitrite (NO3-N + NO2-N) X X X Sulfate X X X Total Dissolved Solids (TDS) X X Total Kjeldahl Nitrogen (TKN) X X X Total Organic Carbon (TOC) X X X X Total Orthophosphate X X Total Phosphorus X X X Total Petroleum Hydrocarbons (TPH) 

X 

Total Recoverable Phenolics X X 
7-4 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 

Table 7-1 (Continued) 

1 TWF assumed to be equal to 2.8 for any of the alkylphenol ethoxylates. 

Note: Octylphenol and nonylphenol should have a higher toxicity than the alkylphenol ethoxylates. July 2009 

Analyte

Pollutants 

Identified in 

the PDS 

Sampling 

Pollutants 

Monitored in 

NPDES 

Permits 

Pollutants Identified 

in Raw ADF in 

Research or 2004-

2006 EPA Sampling 

Pollutants Identified 

in Untreated 

Stormwater in 2004-

2006 EPA Sampling 

Pollutants Ident

in Source Wate

2004-2006 EP

Sampling 

Total Suspended Solids (TSS) X X Metals Aluminum X X Antimony X X X Arsenic X X X Barium X X X Boron X X Cadmium X Calcium X X X X Chromium X X Copper X X X X X Iron X X X X Lead X X Magnesium X X X X Manganese X X Mercury X X Molybdenum X X Potassium X Selenium X X Silver X Sodium X X X X Thallium X Tin X X X Titanium X Vanadium X 
7-5 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 

Table 7-1 (Continued) 

1 TWF assumed to be equal to 2.8 for any of the alkylphenol ethoxylates. 

Note: Octylphenol and nonylphenol should have a higher toxicity than the alkylphenol ethoxylates. July 2009 

Analyte

Pollutants 

Identified in 

the PDS 

Sampling 

Pollutants 

Monitored in 

NPDES 

Permits 

Pollutants Identified 

in Raw ADF in 

Research or 2004-

2006 EPA Sampling 

Pollutants Identified 

in Untreated 

Stormwater in 2004-

2006 EPA Sampling 

Pollutants Ident

in Source Wate

2004-2006 EP

Sampling 

Zinc X X X X X Organics Acetone X X Benzene, toluene, ethylbenzene, xylene (BTEX) 

X X 

Benzoic Acid X Bis(2-Ethylhexyl) Phthalate X Di-n-butyl Phthalate X Diethylene Glycol X N-Dodecane X Ethylene Glycol X X X N-Hexadecane X Methyl Ethyl Ketone X Naphthalene X Phenol X X Propylene Glycol X X X X N-Tetradecane X 1,2,4- Trimethylbenzene X Trichloroethene X Tolyltriazole X Benzotriazole 5-Methyl-1H-benzotriazole X 
7-6 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 

Table 7-1 (Continued) 

1 TWF assumed to be equal to 2.8 for any of the alkylphenol ethoxylates. 

Note: Octylphenol and nonylphenol should have a higher toxicity than the alkylphenol ethoxylates. July 2009 

Analyte

Pollutants 

Identified in 

the PDS 

Sampling 

Pollutants 

Monitored in 

NPDES 

Permits 

Pollutants Identified 

in Raw ADF in 

Research or 2004-

2006 EPA Sampling 

Pollutants Identified 

in Untreated 

Stormwater in 2004-

2006 EPA Sampling 

Pollutants Ident

in Source Wate

2004-2006 EP

Sampling 

Alkylphenols Nonylphenol, total X X Nonylphenol-1-Ethoxylate X X Nonylphenol-2-Ethoxylate X X Nonylphenol-3-Ethoxylate X X Nonylphenol-4-Ethoxylate X X Nonylphenol-5-Ethoxylate X X Nonylphenol-6-Ethoxylate X X Nonylphenol-7-Ethoxylate X X Nonylphenol-8-Ethoxylate X X Nonylphenol-9-Ethoxylate X X Nonylphenol-10-Ethoxylate X X Nonylphenol-11-Ethoxylate X X Nonylphenol-12-Ethoxylate X X X Nonylphenol-13-Ethoxylate X X X Nonylphenol-14-Ethoxylate X X X Nonylphenol-15-Ethoxylate X X X Nonylphenol-16-Ethoxylate X X X Nonylphenol-17-Ethoxylate X X X Nonylphenol-18-Ethoxylate X X X Octylphenol X X Octylphenol-2-Ethoxylate X X Octylphenol-3-Ethoxylate X X Octylphenol-4-Ethoxylate X X Octylphenol-5-Ethoxylate X X 
7-7 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 

Table 7-1 (Continued) 

1 TWF assumed to be equal to 2.8 for any of the alkylphenol ethoxylates. 

Note: Octylphenol and nonylphenol should have a higher toxicity than the alkylphenol ethoxylates. July 2009 

Analyte

Pollutants 

Identified in 

the PDS 

Sampling 

Pollutants 

Monitored in 

NPDES 

Permits 

Pollutants Identified 

in Raw ADF in 

Research or 2004-

2006 EPA Sampling 

Pollutants Identified 

in Untreated 

Stormwater in 2004-

2006 EPA Sampling 

Pollutants Ident

in Source Wate

2004-2006 EP

Sampling 

Octylphenol-6-Ethoxylate X X Octylphenol-7-Ethoxylate X X Octylphenol-8-Ethoxylate X X Octylphenol-9-Ethoxylate X X Octylphenol-10-Ethoxylate X X Octylphenol-11-Ethoxylate X X Octylphenol-12-Ethoxylate X X Total Nonylphenol-3-EthoxylateNonlyphenol-18-Ethoxylate X X X Total Octylphenol-2-EthoxylateOctylphenol-12-Ethoxylate X X 
Technical Development Document for Proposed Effluent 7. Pollutants of Concern 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 7-8 

 The commonly used airfield deicing and anti-icing chemicals are listed below, along with 

the approximate percentage of total pavement chemical usage they comprise: 

• Potassium acetate (64 percent); 

• Propylene glycol-based fluids (12 percent ); 

• Urea (11 percent); 

• Sodium acetate (9 percent); 

• Sodium formate (3 percent); and 

• Ethylene glycol-based fluids (2 percent). 

 EPA collected and analyzed samples of unused, or “raw,” ADF during the sampling 

episodes at DTW and MSP. EPA did not analyze samples for alkylphenols during these sampling 

episodes; therefore, no alkylphenol data are available for the raw ADF. 

 Finally, EPA reviewed research conducted by USGS to determine potential ADF 

constituents. Steven Corsi of USGS conducts research and sampling on ADF and deicing 

stormwater at General Mitchell International Airport in Milwaukee, WI. He has published 

several papers presenting his research and sampling results and has identified the following 

pollutants in ADF stormwater and snowmelt: 

• BOD5; 

• COD; 

• Propylene and ethylene glycol; 

• Alkylphenols (AP), and alkylphenol ethoxylates (APEO); and 

• Benzotriazole (BT) and its methylated derivatives (MeBT). 

Toxic Weighting Factors 

 To assess relative toxicity of the pollutants present in deicing stormwater, EPA 

considered the toxic weighting factors (TWFs) of the pollutants. EPA develops TWFs based on 

toxicity data contained in the EPA Toxics Database.(U.S. EPA, 2007) This database includes 

data from over 100 references and contains aquatic life and human health toxicity data, as well as 

physical/chemical property data, for more than 1,900 pollutants. EPA developed a TWF for 

alkylphenols based on available toxicity information. (ERG, 2007b) Pollutant TWFs, where 

available, are included in Table 7-1. 

7.2 Pollutants of Concern Selection Criteria

 Having identified pollutants that are likely to be present in airport deicing stormwater, 

EPA then considered which pollutants should potentially be controlled. EPA considered the 

following criteria in assessing potential pollutants of concern: 

• Whether the pollutant is present in deicing stormwater from a source other than 

deicing/anti-icing chemical use; 

• Whether the pollutant is discharged in relatively small amounts and/or is likely to 

cause toxic effects; 

• Whether the pollutant is detected in the effluent from a small number of airports 

and is uniquely related to those facilities; or 
Technical Development Document for Proposed Effluent 7. Pollutants of Concern 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 7-9 

• Whether the pollutant can be analyzed by using EPA-approved or other 

established methods. 

After consideration of the criteria listed above, EPA developed a list of those pollutants that are 

considered potential pollutants of concern. 

7.3 Identification of Potential Pollutants of Concern

 EPA compared the pollutants detected in deicing stormwater to ADF constituents and 

determined that many pollutants present in the stormwater are not ADF constituents. Stormwater 

contains pollutants from sources other than ADF; these sources may include, but are not limited 

to, the following: 

• Source water pollutants (present in the water used at the airport facility); 

• Pollutants from aircraft and vehicle fueling; 

• Pollutants from maintenance-related operations; or 

• Pollutants from roof runoff. 

EPA also considered the other criteria listed in Section 7.2 above to assess potential pollutants of 

concern. Below is a summary of EPA’s evaluation of potential pollutants of concern by the 

following analytical categories: classical parameters, metals, and organic pollutants. 

Classical Parameters 

 The major components of both airfield deicing chemicals and aircraft deicing fluids are 

organic and degrade in the environment after their release. Because of this, COD and BOD5

concentrations are generally high in deicing stormwater. Both of these pollutant parameters are 

also good indicators of the amount of acetates, urea, glycols, and formates in deicing stormwater 

and the environmental impacts of the deicing stormwater on oxygen demand in receiving waters. 

 EPA believes that those airports requiring monitoring and control of ammonia, TKN, and 

nitrate/nitrite are likely doing so to monitor discharges of urea. Information collected during 

EPA’s airport site visits seemed to indicate that airports have been phasing out the use of urea for 

airfield deicing. However, EPA’s analysis of urea use from the airport questionnaire has actually 

shown an increase in the amount of urea use during the 2002/2003 through 2004/2005 deicing 

seasons, with approximately the same number of airports using urea in each of those seasons. 

 Several of the classical parameters detected in deicing stormwater are from stormwater, 

dilution water, or other airport operations; these pollutants are not present in ADF but are present 

in deicing stormwater. Pollutants from other airport sources aside from ADF include alkalinity, 

hardness, oil and grease, TPH, and TSS. 

Metals 

 Multiple metals have been detected in samples of airport deicing stormwater. Some of 

these metals were also detected in the ADF samples collected by EPA. Many of these metals are 

not original components of deicing products (e.g., aluminum and chromium); they are present as 

background concentrations from the stormwater or source water used for ADF dilution or they 
Technical Development Document for Proposed Effluent 7. Pollutants of Concern 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 7-10 

are metals picked up by stormwater runoff from aircraft maintenance/operation areas or building 

roofs. 

Organic Pollutants 

 Organic pollutants present in deicing stormwater include propylene glycol, ethylene 

glycol, triazole compounds, alkylphenols, and alkylphenol ethoxylates. Other organics may also 

be present from the breakdown of glycols, urea, acetates, and formates. 

 Toxicity studies conducted by Corsi and others (Corsi et al., 2006) indicate that deicing 

stormwater may exhibit toxicity from the additive compounds included in the aircraft (and in 

some cases) airfield deicing products. 

 Based on these findings, EPA identified the following as potential pollutants of concern 

for the Airport Deicing Category: 

• COD; 

• BOD5; 

• Ethylene glycol; 

• Propylene glycol; 

• Benzotriazole; 

• 5-Methyl-1H-benzotriazole; 

• Nonylphenol, total; 

• Octylphenol, total; 

• Total nonylphenol-3-ethoxylate-nonlyphenol-18-ethoxylate; 

• Total octylphenol-2-ethoxylate-octylphenol-12-ethoxylate; 

• Ammonia as nitrogen; 

• Nitrate/Nitrite; 

• TKN; 

• Antimony; 

• Copper; 

• Iron; 

• Mercury; 

• Molybdenum; 

• Tin; 

• Zinc; and 

• Acetone. 

7.4 Selection of Regulated Pollutants for Proposal

 Table 7-2 lists the potential pollutants of concern identified in Section 7.3, along with an 

explanation of whether EPA selected the pollutant for regulation. Based on the documented 

environmental impacts from airport deicing runoff, EPA focused on regulating those pollutants 

exerting oxygen demand and contributing toxicity to receiving water bodies. EPA found that the 

impacts of slug loads of ADF stormwater on the dissolved oxygen of receiving streams, as well 

as color and odor issues associated with high ADF concentrations in stormwater discharge, are 

well documented. The main component of ADF is glycol, which exhibits significant oxygen 

demand. Research by Corsi (Corsi et al., 2006) also identified potential toxicity concerns that 
Technical Development Document for Proposed Effluent 7. Pollutants of Concern 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 7-11 

may be linked to ADF additives, specifically triazoles and alkylphenols. In conversations with 

ADF manufacturers, EPA has been told that the use of triazole compounds in ADF is being 

discontinued and that triazole use in European ADFs has been phased out. Alkylphenols and 

their ethoxylates have also been identified as potential toxic components of ADF. EPA’s 

sampling data have confirmed the presence of these compounds; however, EPA believes that 

insufficient information is currently available to fully characterize the extent to which these 

compounds are present in deicing stormwater and their impact. 

 For stormwater discharges from airfield deicing operations, EPA focused on the 

continued use of urea. Urea breaks down into ammonia, and the resulting ammonia toxicity in 

receiving streams has helped to discourage urea use as an airfield deicing chemical in the past. 

Alternative airfield deicing chemicals that are less toxic than ammonia are available and are 

predominantly composed of a salt ion (potassium or sodium) and either acetate or formate. When 

inadequately treated, urea-contaminated wastewater also may contribute to nitrogen enrichment 

and eutrophication of receiving waters. EPA evaluated whether regulation of airfield deicing 

stormwater was practical or cost-effective. Since airfield deicing stormwater losses tend to occur 

over large areas and the volumes of dilute stormwater may be very high, at this time, EPA could 

not identify an “economically achievable” means to regulate airfield deicing stormwater other 

then to encourage a complete transition away from urea use. 

 Based on the known environmental impacts from deicing stormwater discharges, EPA 

has selected COD and ammonia as N for proposed regulation. COD is a good indicator 

parameter to monitor the overall oxygen demand resulting from the discharge of glycol-based 

ADFs and any other organic constituents present in the stormwater. Ammonia as N is proposed 

for regulation to ensure that airports cease using urea as an airfield deicer, since other less toxic 

products are available. 

 EPA evaluated the impacts of the airport deicing collection and treatment scenarios on 

both BOD5 and COD discharges. EPA selected COD for regulation and not BOD5 for the 

following reasons: 

• While both of these parameters are good indicators of the glycol-based oxygen 

demand component of deicing stormwater, COD will also capture the oxygen 

demand from nitrogen and other organic components of the stormwater that may 

not be represented in a BOD5 result. 

• COD analyses are simple to conduct and can be measured in real time compared 

to a 5-day test for BOD. 

• COD eliminates the need to consider receiving water temperature when 

evaluating water quality concerns. 

• Toxic ADF additive compounds in deicing stormwater may have a negative and 

variable affect on the acclimation of the active cultures used in BOD analysis, 

making the method less robust than COD analysis for these wastewaters. 
Technical Development Document for Proposed Effluent 7. Pollutants of Concern 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 7-12 

Table 7-2. Potential Pollutants of Concern Selected for Proposed Regulation 

Potential Pollutant of Concern 

Selected for 

Regulation Explanation of Selection or Non-selection for Proposal

BOD5 COD as surrogate 

COD X Proposed for regulation 

Ethylene glycol COD as surrogate 

Propylene glycol COD as surrogate 

Benzotriazole Limited data available to support selection and potential 

discontinued use 

5-Methyl-1H-benzotriazole Limited data available to support selection and potential 

discontinued use 

Nonylphenol, Total Limited data available to support selection 

Octylphenol, Total Limited data available to support selection 

Total nonylphenol-3-ethoxylatenonlyphenol-18-ethoxylate Limited data available to support selection 

Total octylphenol-2-ethoxylateoctylphenol-12-ethoxylate Limited data available to support selection 

Ammonia as nitrogen X Proposed for regulation to monitor urea use 

Nitrate/Nitrite Ammonia as nitrogen as surrogate for urea use 

TKN Ammonia as nitrogen as surrogate for urea use 

Antimony Limited impact data for metals and metal treatment not 

included in BAT 

Copper Limited impact data for metals and metal treatment not 

included in BAT 

Iron Limited impact data for metals and metal treatment not 

included in BAT 

Mercury Limited impact data for metals and metal treatment not 

included in BAT 

Molybdenum Limited impact data for metals and metal treatment not 

included in BAT 

Tin Limited impact data for metals and metal treatment not 

included in BAT 

Zinc Limited impact data for metals and metal treatment not 

included in BAT 

Acetone COD as surrogate 
Technical Development Document for Proposed Effluent 7. Pollutants of Concern 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 7-13 

 EPA is not proposing to regulate metals, even though in some cases they may be present 

from deicing operations and not just maintenance or fueling operations. EPA’s sampled 

concentration levels for those metals identified as potential pollutants of concern are, in general, 

low (usually below EPA water quality standard levels). As such, EPA does not have sufficient 

data to support proposing a regulation at the national level. EPA believes that any site-specific 

concerns with detected metals can be addressed through facility-specific effluent limitations in 

NPDES permits. 

7.5 References 

USEPA. 2000. Preliminary Data Summary: Airport Deicing Operations. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. EPA-821-R-00-016. (August). 

http://www.epa.gov/guide/airport 

ERG. 2006. Memorandum to Brian D’Amico and Eric Strassler (U.S. EPA) from Steve 

Strackbein and Cortney Itle (ERG): Airport Deicing Operations SWPPP and Permit Review. 

(November 8). DCN AD00859. 

ERG. 2007a. Memorandum to Brian D’Amico and Eric Strassler (U.S. EPA) from Jason 

Huckaby (ERG): Airport Deicing Operations NPDES Permit Review Summary. (April 16) DCN 

AD00611. 

Corsi, SR, et al. 2003. “Nonylphenol Ethoxylates and Other additives in Aircraft Deicers, Antiicers, and Waters Receiving Airport Runoff.” Environmental Science & Technology, 37:4031-

4037. DCN AD00083. 

USGS. 2004. General Mitchell International Airport and U.S. Geological Survey. Data summary 

for monitoring and assessment of changes in water quality due to deicer management Water 

Years 1997-2004. (September). DCN AD00085. 

Corsi, SR, et al. 2000. “Aircraft and Runway Deicers at General Mitchell International Airport, 

Milwaukee, Wisconsin, USA. Biochemical Oxygen Demand and Dissolved Oxygen in 

Receiving Streams.” (November 22). DCN AD00081. 

Corsi, SR, et al. 2006. “Characterization of Aircraft Deicer and Anti-icer Components and 

Toxicity in Airport Snowbanks and Snowmelt Runoff.” Environmental Science & Technology.

DCN AD00326. 

US EPA. 2006. Toxic Weighting Factor Development in Support of CWA 304(m) Planning 

Process. U.S. Environmental Protection Agency/Office of Water. Washington, D.C. (June). DCN 

AD00861. 

ERG. 2007b. Memorandum from Maureen Kaplan (ERG) to Mary Willett (ERG): Toxic 

Weighting Factors (TWFs) for Nonylphenol, Octylphenol, and Alkyl Phenol Ethoxylate. (March 

30). DCN AD00862. 

USEPA. 2007. Ecotoxicology (“ECOTOX”) Database. U.S. Environmental Protection Agency. 

Washington, D.C. www.epa.gov/ecotox/ 
Technical Development Document for Proposed Effluent 8. Pollution Prevention and Treatment Technologies 

Limitation Guidelines and Standards for the Airport Deicing Category Applicable to Airport Deicing Operations 

July 2009 8-1 

8. POLLUTION PREVENTION AND TREATMENT TECHNOLOGIES APPLICABLE TO 

AIRPORT DEICING OPERATIONS

 The NPDES permit program, along with the emergence of problems such as fish kills and 

odor reports, have prompted airports and airlines to investigate a wide range of pollution 

prevention and treatment practices. These practices are designed to eliminate or minimize the 

environmental impact of ADF and airfield pavement chemicals without compromising safety. 

This section summarizes the common techniques used to collect deicing stormwater and the 

treatment or recycling steps implemented prior to discharge. This section also discusses pollution 

prevention practices used by U.S. airports and airlines. 

 Each method of collection, treatment or recycling, or pollution prevention selected by an 

airport or airline often depends on a variety of airport-specific or airline-specific factors, 

including climate, amount of chemical deicing and anti-icing agents applied, number of airlines 

operating at a particular airport, aircraft fleet mix, number of aircraft operations, costs, presence 

of existing infrastructure, availability of land, and affect on aircraft departures. EPA recognizes 

that some of the practices discussed in this section may not be practical or economically feasible 

for all U.S. airports. 

 Section 8.1 discusses deicing stormwater collection, Section 8.2 describes deicing 

stormwater treatment and recycling, and Section 8.3 presents pollution prevention (e.g. product 

substitution) practices. 

8.1 Deicing Stormwater Collection

 The collection of deicing stormwater from aircraft deicing/anti-icing operations helps 

prevent or minimize discharges at stormwater outfalls. Airports currently use a variety of 

collection and conveyance methods, including designated aircraft deicing pads, gate and ramp 

area drainage collection systems, grassed swales, storm sewer plugs, and specially designed 

glycol recovery vehicles (GRVs), each of which is discussed in Section 8.1.1. Individual airports 

often rely on a combination of these collection strategies to effectively collect ADFcontaminated stormwater. 

 Section 8.1.2 presents common methods for storing and discharging deicing stormwater, 

including detention ponds or constructed wetlands, retention ponds, permanent storage tanks or 

frac tanks, discharge to a publicly owned treatment works (POTW), trucking waste off site, or 

any combination of these methods. The following subsections describe in detail the various 

wastewater collection methods used by the industry. 

8.1.1 Deicing Stormwater Collection and Conveyance 

 This subsection describes the various wastewater collection and conveyance methods 

commonly used by airports. Airport stormwater collection systems are designed to collect 

deicing stormwater from several different locations at which deicing operations are performed, 

including aircraft deicing at centralized deicing pads, at the gates, or at parking or cargo aprons. 

Collection systems may collect stormwater from airfield deicing locations including; ramps, 

taxiways, and runways. Common methods of collecting and conveying deicing stormwater 

include deicing pad collection systems, gate and ramp area drainage collection systems, grassed 

swales, storm sewer plugs, and GRVs. 
Technical Development Document for Proposed Effluent 8. Pollution Prevention and Treatment Technologies 

Limitation Guidelines and Standards for the Airport Deicing Category Applicable to Airport Deicing Operations 

Deicing Pads 

 A centralized deicing pad is a facility on an airfield built specifically for aircraft deicing 

operations. It is typically a paved area adjacent to a gate area, taxiway, or runway, and 

constructed with a drainage system separate from the airport's main storm drain system. It is 

usually constructed of concrete with sealed joints to prevent the loss of sprayed ADF through the 

joints. The pad's collection system is typically connected to a stormwater storage facility, which 

then may send the stormwater to an on-site or off-site treatment facility. 

 Deicing pads restrict aircraft deicing to a confined area, and allow for the capture of 

deicing stormwater at the point of generation, thereby minimizing the volume of spent deicing 

fluid discharged in an uncontrolled manner. Aircraft deicing pads also centralize deicing 

activities, which allow airports to more easily collect high concentration ADF-contaminated 

stormwater, creating a better opportunity for recycle and recovery of glycol. Transporting spent 

ADF off site to wastewater treatment plants, POTWs, or recycling facilities is also more 

economical when the amount of deicing stormwater is minimized. 

 One benefit of deicing aircraft on deicing pads instead of at the gates is that it moves 

aircraft from the gate areas, thereby opening gates for arriving aircraft. Another benefit is that 

pads are commonly located near the heads of runways, where planes can be deiced just prior to 

takeoff; as a result, less Type IV anti-icing fluid may be necessary due to shorter holdover times, 

reducing the amount of glycols transferred off of the deicing pad or released into the air. 

Figure 8-1 shows an example of a centralized deicing pad with fixed boom sprayers. 

Figure 8-1. Deicing Pad Equipped with Fixed Deicing Booms at Pittsburgh Airport 

July 2009 8-2 
Technical Development Document for Proposed Effluent 8. Pollution Prevention and Treatment Technologies 

Limitation Guidelines and Standards for the Airport Deicing Category Applicable to Airport Deicing Operations 

Gate and Ramp Area Drainage Collection Systems 

 Other than deicing pads, the most common areas for deicing operations are passenger 

terminal gates and aircraft parking or cargo ramps/aprons. To collect wastewater generated at 

these locations, some airports have installed collection systems or modified existing stormwater 

drainage systems. The typical collection system consists of graded concrete pavement with 

trench or square drains that convey wastewater to a storage facility or discharge point through a 

diversion box. Figure 8-2 shows an example of a gate deicing area. Gate and ramp collection 

systems generate low concentration, ADF-contaminated stormwater because more stormwater 

gets mixed in with the spent ADF and because there are increased fugitive losses due to vehicle 

traffic around the planes. For some stormwater drainage systems, a diversion box allows 

uncontaminated stormwater to be diverted to stormwater outfalls. 

Figure 8-2. Mobile Deicer Truck Performing Gate Deicing at Chicago O’Hare Airport 

Grassed Swales 

 Grassed swales are shallow, open-channel engineered landscape features that are covered 

with grass and other erosion-resistant vegetation. Grass swales slow and control stormwater flow 

rates and act as a filter to lower pollution loads through the removal of solids. Swales are 

designed to treat runoff by filtering the stormwater through vegetation and subsoil, and allow 

stormwater to infiltrate underlying soils. To work effectively, stormwater discharged into a swale 

should occur in a thin, sheet flow pattern to maximize infiltration. Grassed swales are popular 

because they are low cost compared to other control measures (CASQA, 2003) 

Plug and Pump Systems 

 Some airports use storm drain inserts or plugs to close the drains and allow the collection 

of ADF-contaminated stormwater within the existing airport stormwater drainage system. When 

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aircraft are undergoing deicing/anti-icing, the inserts are installed to force contaminated 

stormwater to pool in drainage piping until the stormwater can be vacuumed or pumped out. This 

practice prevents manholes and stormwater piping from overflowing. Once deicing/anti-icing 

activity ends and the contaminated stormwater is removed, the storm drain inserts can be 

removed, or deactivated allowing uncontaminated stormwater to pass through the drain. Plugand-pump collection systems are applicable to airports that deice at the gate. One benefit of 

deicing at the gate is that it allows the components of the existing collection system 

infrastructure (i.e. existing storm sewers) to be incorporated into the plug-and-pump collection 

system and can reduce the costs associated with deicing control. 

 Minneapolis-St. Paul International (MSP) airport is one example of an airport using a 

plug and pump collection system. At MSP airport, 30 percent of deicing operations take place in 

the airport’s sixteen plug and pump containment areas. During the deicing season, the plug and 

pump areas are fitted with compression plugs in the storm sewers to prevent contaminated or 

potentially contaminated stormwater from being discharged. The stormwater plugs convert the 

stormwater sewer pipes and manholes into individual stormwater retention systems that can each 

retain between 5,000 to 42,000 gallons of stormwater. These individual stormwater retention 

systems are monitored during the day to determine how full they are (to prevent overflow) and to 

determine how to manage the ADF-contaminated stormwater based on its composition and 

strength. Contaminated stormwater is pumped or vacuumed from the sewer pipes and tested to 

determine the glycol concentration. Based on the glycol concentration of the wastewater, it is 

stored in either a low concentration storage tank or a high concentration storage tank prior to 

being shipped offsite for recycling (USEPA, 2008a). 

Glycol Recovery Vehicles (GRVs) 

 GRVs are specially-designed vehicles that remove glycol and other deicing fluid runoff 

from airport deicing pads and gate locations by vacuuming liquid from pavement surfaces. 

Figure 8-3 shows an example of a GRV. GRVs help prevent stormwater from infiltrating and 

contaminating surrounding waterways. Once ADF-contaminated wastewater is vacuumed from 

airport surfaces, it is typically transported to an on-site storage facility where the airport can treat 

and discharge, recycle or ship the waste offsite for treatment or recycling. 
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Figure 8-3. Glycol Recovery Vehicle 

8.1.2 Deicing Stormwater Storage 

 This subsection describes the various stormwater storage methods commonly used by 

airports. Airport stormwater storage systems are designed to collect deicing stormwater from 

several different locations around an airport and to accommodate highly variable flows and 

volumes. Common methods of stormwater storage at airports include; detention ponds, 

equalization ponds, retentions ponds, and storage or frac tanks. 

Detention Ponds and Equalization Ponds 

 Detention ponds are open-water ponds that collect deicing stormwater runoff from 

runways and other airport property. Detention ponds are designed to temporarily hold deicing 

stormwater anywhere from one day to two months and allow solids to settle while reducing 

oxygen demand through surface oxygenation and volatilization prior to discharge to receiving 

waters. Detention ponds can be lined or gravel-filled and may contain microscopic bacteria that 

biodegrade deicing and anti-icing materials. Pump stations are commonly implemented to pump 

metered runoff to discharge or further treatment. Detention basins often use aeration to increase 

dissolved oxygen levels. 

 Equalization ponds are detention ponds designed to thoroughly mix ADF-contaminated 

stormwater so that consistent concentrations of pollutants can be pumped from the pond to 

treatment/recycling operations or to other disposal. Equalization ponds may contain moving 

parts, such as mixers, to ensure the liquid in the pond is completely mixed. 

Retention Ponds 

 Retention ponds are designed to hold collected deicing stormwater indefinitely. Usually 

the pond is designed to allow overflow to drain to another location (e.g., a second retention pond 

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or other overflow structure) when the water level gets above the pond capacity. Retention ponds 

can also be used to treat deicing stormwater as part of a batch process (using chemical addition 

and/or aeration) prior to discharge. With retention ponds, airports can collect ADF-contaminated 

runoff throughout a deicing season and have the option of trucking it off site for treatment or 

treating it on site in the retention pond. 

Advantages and Disadvantages of Ponds in Treating ADF-Contaminated 

Stormwater 

 Ponds require large areas for installation, and the normal operations of these systems 

require treatment for many months after the end of the annual deicing season, before the 

wastewater can be discharged. FAA discourages the installation of new stormwater retention 

ponds at airports, as they can be a lure for migratory birds, which are a safety hazard for aircraft. 

(FAA, 2007). For airports with existing retention ponds, however, where adequate storage 

capacity is available, aerated pond systems may be able to provide efficient treatment. See 

section 8.2.2 below for further discussion of aerated pond systems. Figure 8-4 shows an example 

of an airport pond used for deicing stormwater storage. 

Figure 8-4. Pond for Deicing Stormwater Storage at Denver International Airport 

Storage Tanks and Frac Tanks 

 Airports that treat ADF-contaminated stormwater often use storage tanks to store the 

stormwater prior to on-site treatment or transfer off site. These types of tanks can be constructed 

as aboveground tanks or underground tanks. Collecting and storing deicing stormwater in storage 

tanks allows an airport to equalize pollutant concentrations and can allow for a consistent flow 

rate into an on-site treatment system, which is important to ensuring consistent treatment results. 

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 Frac tanks are mobile storage tanks that can provide temporary storage of collected 

deicing stormwater or can be connected by a hose or pipeline to an alternative area. Frac tanks 

can be easily removed from airport grounds and replaced with empty tanks when existing tanks 

fill up. Figure 8-5 shows an example of two frac tanks. 

Figure 8-5. Frac Tanks 

8.2 Treatment and Recycling

 Because of the high oxygen demand of ADF-contaminated stormwater, some airports 

must treat their deicing stormwater prior to discharge. This section describes the use of oil/water 

separators and dissolved air flotation (DAF) units that are used predominantly to address 

stormwater contaminants that are not specifically from deicing operations, e.g., oil and grease 

and solids(discussed in Section 8.2.1) and biological treatment through either on-site or off-site 

treatment systems (discussed in Section 8.2.2). 

 Recycling of glycol from spent ADF decreases the amount ADF-contaminated 

stormwater that reaches and potentially impairs surface and ground waters. The process to 

recover glycol from spent ADF may take several steps. The recycle and recovery technologies 

currently in use by U.S. airports include membrane separation (discussed in Section 8.2.3), 

filtration (discussed in Section 8.2.4), mechanical vapor recompression (discussed in Section 

8.2.5), and distillation (discussed in Section 8.2.6). 

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 Recovered glycol is generally sold to help recover expenses associated with ADF 

application, collection, and control. EPA has observed that on-site recycling can be successful 

and economically viable at airports that collect large enough volumes of high-concentration 

ADF-contaminated stormwater. Key criteria for designing a recovery system include the type of 

ADF being collected, glycol concentration of the stormwater, total consumption of ADF per 

season, and peak ADF volume application rates. Other factors to consider are the number of 

deicing days per season at an airport and future air traffic plans. 
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8.2.1 Oil/Water Separators and DAF 

 Oil/water separators increase the glycol concentration of ADF-contaminated stormwater 

streams by removing oily constituents from the waste stream. Aboveground skimmer and 

underflow weir oil/water separators are used at airports. These types of separators typically 

diffuse influent wastewater across the entire face of the separator prior to entering the separation 

chamber. The separation chamber consists of perpendicular media designed to separate small oil 

droplets from solution. Once the oil floats to the top of the separation chamber a skimmer is 

utilized to remove the oil from the surface and store in a separate location (e.g., storage tank). 

Static inclined plate oil/water separators are also used at airports and pass floatable liquids over a 

single inclined plate (perpendicular). Passing fluid over the inclined plate reduces the velocity of 

the influent stream and prevents channeling by spreading out the flow over the entire separator. 

An additional benefit provided by plate separators is that they allow sludge or heavy solids to 

break away from oil droplets and to settle to the bottom. Oil/water separation is not useful in 

removing glycol and other dissolved pollutants in ADF-contaminated stormwater. 

Dissolved air flotation (DAF) clarifies wastewaters by removing suspended matter such 

as oil or solids. The system dissolves air in wastewater under pressure and then releases the air at 

atmospheric pressure in a flotation tank, allowing the released air to form tiny bubbles that 

adhere to suspended matter in the wastewater. These bubbles float to the surface where the 

suspended matter can be removed by a skimming device. Like oil/water separators, DAF units 

are not useful in removing glycols and other dissolved pollutants in ADF-contaminated 

stormwater. 

 EPA conducted a site visit at Seattle-Tacoma International (SEA) airport, which operates 

a DAF unit. The airport’s DAF treatment process consists of adding coagulation chemicals to the 

influent wastewater in a rapid mix chamber, gently mixing the chemicals in a flocculation tank to 

encapsulate suspended solids and oil droplets, and removing the floc and other oil particles. Air 

bubbles released into the wastewater attach to the suspended solids and colloidal oil particles, 

forming a floating material that is removed and pumped to a sludge sump. The treated water in 

the DAF units flows over an outlet weir where it is combined with other waters prior to 

discharge to Puget Sound. (USEPA, 2007a). 

8.2.2 Biological Treatment 

 This subsection describes the treatment of ADF-contaminated stormwater through 

biological processes. Biological treatment consists of two types of processes, aerobic or 

anaerobic. The treatment can occur onsite at an airport or off site at POTWs or other treatment 

facilities. 

POTW Treatment of ADF-contaminated Stormwater 

 Where practical, airports discharge their deicing stormwater to a POTW for biological 

treatment. POTW systems generally operate using activated sludge in an aerobic biological 

treatment system and may also incorporate anaerobic digestion of the sludge generated. Airports 

may be prevented from discharging to a local POTW due to one or more or the following 

reasons: (1) limited hydraulic or loading capacity at the POTW, (2) high POTW wastewater 
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treatment and/or conveyance fees, (3) inability of the local POTW to handle highly variable 

pollutant loadings, and (4) airport infrastructure constraints. 

Aerated Lagoons or Detention Ponds 

 Aerated biological treatment systems used on site at airports are effective for treating 

low-concentration ADF-contaminated stormwater. These systems commonly consist of aerated 

treatment lagoons or ponds that are open to the atmosphere, though open-topped tank systems 

may also be used. Treatment lagoons and ponds work well with large volumes (millions of 

gallons) of wastewater and are usually operated as a batch process. Aeration in lagoons and 

ponds increases the level of dissolved oxygen in the water, which is needed to decompose 

organic matter such as glycols. In addition, the presence of oxygen helps to oxidize certain 

elements that are suspended in the water and oxidation causes some materials to become heavier 

so that they will settle out of the water column quicker. Without proper aeration, bacteria will not 

be able to decompose the organic matter in a pond quickly or efficiently. Aeration devices are 

used to agitate the lagoon or pond surface, which helps to transfer atmospheric oxygen into the 

wastewater to promote biological treatment processes, to vent carbon dioxide and other gaseous 

elements from the water and also to increase the amount of wastewater exposed to ambient air, 

allowing other volatile organics to oxygenate and evaporate. 

 The Greater Rockford airport is an example of an airport operating an aerated pond 

treatment system for deicing stormwater. Greater Rockford airport collects ADF-contaminated 

stormwater throughout the deicing season into a 16-million gallon aerated detention pond. Their 

aerobic digestion system consists of the aerated detention pond, a settling pond, a recycling 

pump, and a chemical addition building. The biodegradation of glycol is temperature-dependant 

and predominantly occurs during the spring and early summer months when ambient 

temperatures are higher. Airport personnel monitor the process, adding nutrients, antifoaming 

agents, and pH adjustment chemicals as needed. When the BOD5 concentration of the pond has 

been reduced to less than 30 mg/L, airport personnel discharge the treated stormwater from the 

settling pond to Rock River (USEPA, 1999). 

 Figure 8-6 shows an aerated pond installation at Portland Airport. 
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Figure 8-6. Aerated Pond Installation at Portland Airport 

Anaerobic Treatment 

 Anaerobic treatment systems can effectively treat ADF-contaminated stormwater with a 

range of glycol concentrations. This type of treatment usually occurs in a closed tank in which 

microscopic bacteria in an oxygen-deficient environment biodegrade deicing and anti-icing 

materials. In anaerobic treatment systems, microorganisms consume the organic matter and 

convert it to methane and carbon dioxide in the absence of oxygen, which creates much less 

sludge than an aerobic system. 

 Anaerobic Fluidized Bed (AFB) treatment is a demonstrated technology for addressing 

ADF-contaminated stormwater at both the Albany, New York (ALB) and Akron/Canton, Ohio 

(CAK) airports. The AFB treatment system uses a vertical, cylindrical tank in which the ADFcontaminated stormwater is pumped upwards through a bed of granular activated carbon at a 

velocity sufficient to fluidize, or suspend, the media. A thin film of microorganisms grows and 

coats each granular activated carbon particle, providing a vast surface area for biological growth. 

The anaerobic microorganisms that develop occur naturally in sediment, peat bogs, cattle 

intestines, and even brewer's yeast. Breakdown products from the AFB treatment system include 

methane, carbon dioxide and new biomass. Effluent from the AFB can be discharged to a local 

POTW or, in most cases, directly to surface water. Figure 8-7 presents a diagram showing the 

major components of a typical AFB treatment system (ERG, 2007). 

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Figure 8-7. Typical Anaerobic Fluid Bed Treatment System for Treatment of Stormwater 

Contaminated by ADF 

Land Application and Constructed Wetlands 

 Low-concentration deicing stormwater may also be treated on-site at an airport using 

either land application or discharge through constructed wetlands. Land application involves 

spraying deicing stormwater onto a land surface for infiltration and biological degradation within 

the soil. As an example, Salt Lake City International (SLC) airport, uses land application to 

dispose of batch volumes of low-concentration deicing stormwater on a periodic basis. The 

system involves spraying approximately 300,000 to 400,000 gallons of stormwater over nutrientenriched land using agricultural wheels. The application occurs over a two day period at a rate of 

about one gallon per square foot. The sprayed glycol then degrades in the soil over a week to 

month long period (USEPA, 2008b). Since glycol-based ADFs readily degrade in both high clay 

and sandy soil systems, this type of system can be effective for low concentrations and limited 

volumes. Biodegradation occurs in the soil through carbon respiration of soil microbes, which 

consume oxygen and release carbon dioxide. Zurich International Airport, Switzerland, also uses 

a spray irrigation system for ADF treatment. At that airport, a heated sprinkler system applies 

spent ADF to a 20 ha (49.4 acre) area. (Jungo, E. and P. Schob, 2005, Jungo, E. 2005) 

 Constructed wetlands are artificial marshes or swamps placed inline with stormwater 

drainage at airports. The wetlands act as biofilters and help remove sediments and pollutants 

such as heavy metals from the wastewater. Physical, chemical, and biological processes combine 

in wetlands to remove contaminants from the wastewater. Discharge from constructed wetlands 

can also be collected and treated if treatment from the wetlands is insufficient to meet discharge 

permit limits or it can be discharged to a POTW or surface water. Airports that use constructed 

wetlands for treatment include London Heathrow and Toronto, Canada and in the United States, 

EPA is aware of two recently constructed systems at Buffalo Niagara International Airport and 

Washington Dulles International Airport. 

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 Buffalo Niagara International Airport, Buffalo, NY, installed an engineered wetland 

system in 2009. The system consists of a subsurface flow wetland with forced bed aeration. 

Figure 8-8 presents a photo of the wetland systems at Buffalo Niagara. (Jacques Whitford 

NAWE, 2008, Minkel, K. et. al., 2009) Washington Dulles International Airport has also 

recently installed constructed wetland biological treatment units adjacent to the airport’s new 

runway to provide treatment to runway and fugitive ADF stormwater runoff in the area. The 

wetland units utilize a complex system of collection and distribution pipes and the design allows 

for even distribution of runoff to maximize effective treatment across each unit. Each wetland 

unit incorporates multiple layers of sand, stone and a special soil mixture, topped with specific 

surface vegetation including cattails and other plant species native to the mid-Atlantic region. 

The vegetation was selected for its tolerance to flooding, extensive root depth, oxygen-carrying 

capacity of the root system, and poor wildlife habitat. Contaminated stormwater is piped to the 

wetland units where contaminants are absorbed by the plants’ root system, broken down by soil 

microorganisms, or physically filtered by the media comprising each layer. (ERG, 2009) 

Figure 8-8. Engineered Wetlands Installation at Buffalo Niagara Airport 

8.2.3 Membrane Separation 

 Membrane separation is an efficient one- or two-step process utilized in recycling spent 

ADF that incorporates ultrafiltration (UF) and/or reverse osmosis (RO). In an UF/RO process, 

fluid is filtered at a high temperature (75o C) using an ultrafiltration membrane as stage one. 

Next, the deicing fluid (ultrafiltration filtrate) can be dewatered using a reverse osmosis 

membrane as stage two. Since the ultrafiltration membrane is effective at removing contaminants 

such as turbidity, color and odor, reverse osmosis stage two is used for dewatering and glycol 

separation. The combined UF/RO process will produce a final glycol concentration of 

approximately 10 percent from an original concentration ranging between 0.5 and 4 percent. 

Pittsburgh International airport (PIT) is an example of an airport using this type of system. The 

PIT system first treats ADF-contaminated stormwater through an ultrafiltration unit to remove 

suspended solids. At this point, the stormwater is 0.5 to 4 percent propylene glycol. The 

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stormwater is next treated through a reverse osmosis unit. Following reverse osmosis, the 

stormwater is split into two outputs: 1) concentrate that is approximately 10 percent propylene 

glycol, and 2) permeate that has a very low glycol concentration. The concentrated propylene 

glycol is transported off site for further processing and the permeate that contains small amounts 

of glycol, cBOD and COD can either be discharged to surface water, or to a POTW for further 

processing (USEPA, 2006). 

8.2.4 Filtration 

 Primary filtration, which removes solids greater than 10 microns, is commonly the first 

step in glycol recycling systems because it removes suspended solids and prevents subsequent 

processing units from plugging. Popular primary filters used in glycol recycling are made of 

either polypropylene cartridges or bag filters.

8.2.5 Mechanical Vapor Recompression 

 Mechanical vapor recompression (MVR) is an evaporation method that uses 

mechanically driven compressors or blowers to increase the pressure of the vapor produced. The 

increase in pressure causes the vapor’s temperature to increase, which allows it to heat the liquid 

being concentrated. Benefits of using MVR in glycol recycling include: 

• Low specific operating costs; 

• Low specific energy consumption; 

• Short residence times of the product; and 

• Simplicity of the process. 

 EPA conducted a site visit and subsequent sampling episode at Denver International 

(DEN) airport, which operates MVRs in the following manner. MVRs concentrate the deicing 

pad storage tank influent, which ranges from 1 to 12 percent propylene glycol, to a final 

concentration of 50 to 55 percent glycol. Each MVR has a capacity of 25,000 gallons per day. 

The effluent from the MVRs goes to a storage tank where it is stockpiled prior to being sent to a 

distillation system (USEPA, 2007b). 

8.2.6 Distillation 

 Distillation can be an effective way to recycle glycol by separating the water from the 

glycol in ADF-contaminated stormwater. A drawback of distillation is that it creates 

contaminated washdown water that cannot be discharged and must be treated further. Distillation 

columns are also very large and expensive. Because distillation is energy-intensive, it is 

generally not cost-effective to distill and recycle waste glycol solutions at low concentrations 

(less than 15 percent). Design variables include temperature, distillation column height, and 

reflux ratio. This process is commonly done in batches to ensure proper distillation and desired 

results. 

 EPA conducted site visits at SLC and DEN airports, both of which operate distillation 

columns. 
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• At DEN airport, the distillation system runs 24 hours a day for a three-week cycle 

and processes about 225,000 gallons of propylene glycol before the system is 

halted for cleaning and maintenance. The distillate from the distillation column is 

discharged to the airport’s storage ponds. The distillation column bottoms 

compile sludge that is classified as specialized nonhazardous waste. The 98 to 99 

percent propylene glycol from the distillation column is pumped to a polisher 

(USEPA, 2007b). 

• At SLC airport, 40 to 45 percent glycol-concentrated stormwater is passed 

through a finisher to increase the concentration to approximately 70 to 80 percent 

glycol and then discharged to a storage tank. The stored concentrate is sent to a 

distillation column where it is heated to 250 to 260° F to produce a final product 

of 100 percent glycol. Distillate from the distillation column is discharged to a 

storage tank and the column bottoms are disposed of in an incinerator (USEPA, 

2008b).

8.3 Pollution Prevention and Product Substitution Practices

 Pollution prevention practices reduce the generation or discharge of pollutants produced 

during aircraft/airfield deicing operations. Pollution prevention practices implemented 

throughout the aviation industry include infrared deicing (discussed in Section 8.3.1), forced-air 

deicing (discussed in Section 8.3.2), product substitution practices (discussed in Sections 8.3.3 

and 8.3.4), and best management practices (BMPs) (discussed in Section 8.3.5). 

8.3.1 Infrared Deicing 

 Infrared heating is the transmission of energy by means of electromagnetic waves or rays. 

Infrared energy is invisible and travels at the speed of light in straight lines from the heat source 

(the emitter) to all surfaces and objects (the receivers) without significantly heating the space 

(air) through which it passes. This heating process is much faster than conventional heating 

mechanisms used by conventional deicing (convection and conduction), where the deicing fluid 

spray is cooled by ambient air. 

 Infrared (IR) heating systems have been used at a few U.S. airports for several years and 

have been demonstrated to effectively deice aircraft while substantially reducing ADF usage. 

Currently, infrared deicing systems are used at two large hub airports, John F. Kennedy and 

Newark Liberty, and one non-hub airport, Rhinelander-Oneida County, Wisconsin. Figure 8-9 

shows a picture of the infrared hangar at John F. Kennedy (JFK) airport. 
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Figure 8-9. Infrared Hangar at JFK Airport 

(Photo courtesy of Radiant Aviation Services, Inc.) 

 Infrared-based aircraft deicing systems offer two advantages over traditional glycol-based 

deicing methods. From an environmental standpoint, they can greatly reduce the amount of 

glycol-based fluids used for aircraft deicing, while from an operational standpoint, they are 

relatively inexpensive to operate, as they use natural gas or propane as fuel. 

 Any infrared deicing facility design must take into account the physical characteristics of 

all aircraft that will use the system. Design factors include the maximum tail height, the shape of 

tails, maximum wingspans, and differences in the length and width of the fuselage. The site 

selected for an infrared deicing system must comply with the same FAA regulations that apply to 

glycol-based aircraft deicing facilities, including aircraft separation rules, air traffic control tower 

line-of-sight criteria, and requirements to not interfere with radar signals, navigational aides, and 

airport lighting. FAA issued a new Advisory Circular in 2005 specifically for infrared deicing 

facilities (FAA, 2005). As with traditional aircraft deicing facilities, an infrared deicing facility 

must provide taxiways that allow aircraft to bypass the deicing facility. 

 While EPA encourages the use of this technology, industry practice thus far has 

suggested that it may not be applicable at all airports. Because IR systems are not widely 

available or used, EPA does not propose to identify IR as an available technology for the 

purposes of establishing effluent guidelines. However, the Agency may reconsider this 

technology, if sufficient data support a conclusion that the technology is available. Documents 

provided by a vendor claim that use of an IR system can reduce the amount of Type I ADF 

required by up to 90 percent per aircraft (Radiant Aviation, 2008; ERG, 2004; Belcher-Hoppe 

Associates, Inc., 2004). 

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8.3.2 Forced Air Deicing 

 Forced air deicing uses large volumes of air at low pressure to remove loose 

accumulations of snow and ice from an aircraft prior to chemical deicing. Aircraft deicing trucks 

or fixed booms equipped with forced air nozzles help reduce the amount of glycol that is used 

during deicing and defrosting operations. In light snow conditions, forced air may completely 

replace the need for deicing fluid. For light frost and light deicing events, fluid-injected forced 

air can be used to reduce the amount of deicing fluid by up to 75 percent. For heavy deicing 

events, a fluid forced air technique is used. This technique requires the ADF application rate 

(gallons per minute or gpm) sprayed from the boom to be reduced from 60 gpm to 40 gpm to 

achieve a 25 percent reduction in deicing fluid per aircraft. Forced air deicing can reduce 

operational expenses, environmental impacts, and subsequent environmental monitoring or 

remediation expenses (Icewolf product flyer; IDS, 2006). 

8.3.3 Aircraft Deicing/Anti-Icing Product Substitution Practices 

 One solution to the environmental problems associated with glycol-based 

ADF is replacing such fluids with more environmentally friendly products. ADFs must comply 

with Aerospace Material Specifications (AMS) published by SAE International, an independent 

standards development organization that works cooperatively with the FAA. These standards—

AMS 1424 for Type I fluids and AMS 1428 standards for Type IV fluids--require a specified 

level of product performance and compatibility and any alternative product must meet the same 

standards. To be economically viable, alternative products must also be of comparable price and 

be at least as effective in maintaining air safety as the glycol-based fluids they replace. 

 EPA is aware of one non-glycol, plant-derived product currently being marketed by 

Cryotech Deicing Technology. A new Type I ADF product called “DFSustain” uses 1,3-

propanediol rather than propylene glycol, and is manufactured by a fermentation process using 

cornstarch. The manufacturer claims performance equal or better than PG or EG-based deicers. 

 Table 8-1 lists other aircraft deicing alternatives that EPA is aware of based on literature 

reviews, industry meetings, and site visits. In addition, the airport and airline industry 

associations as well as U.S. Air Force have conducted and are continuing to conduct research 

into other potential substitutes for propylene glycol and ethylene glycol-based fluids. 

Table 8-1. ADF Alternatives 

Alternative Comments 

Propylene Glycol ADF usage data indicates a trend towards greater propylene glycol use as an 

alternative to ethylene glycol use. 

Hot Air, Forced Air, and 

Tempered Steam Deicing 

The use of hot air, forced air, or tempered steam when deicing aircraft provides an 

alternative to typical deicing fluid application techniques using deicing trucks with 

conventional spray nozzles alone. These alternatives can provide more effective 

deicing than conventional spraying technologies and result in lower ADF usage. 

Infrared Deicing Infrared deicing provides an alternative to conventional ADF usage and can greatly 

reduce (though not eliminate) the use of ADFs for deicing and anti-icing. 

Cryotech Bio-PDOTM This bio-based product is currently being marketed as an alternative to 

conventional propylene glycol-based Type I fluids. 

Warm Fuel for Wing Deicing Alternative to defrost deicing with ADF. 
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8.3.4 Airfield Deicing Product Substitution Practices 

 Environmental problems associated with past airfield deicing products like urea led to the 

development of the alternative airfield deicing chemicals used today. Potassium acetate has 

replaced urea as the primary airfield deicer at many U.S. airports. The U.S. Armed Forces no 

longer purchases airfield deicers that contain urea and instead use potassium acetate, sodium 

acetate, and sodium formate. These airfield deicers are highly effective at low temperatures, 

exert much lower oxygen demand than urea, and offer less environmental impact. 

 The aviation industry is currently evaluating the impact of common airfield deicing 

chemicals on the environment, runway infrastructure, and chemical corrosion of aircraft carbon 

brakes. Based on the results of this work, EPA anticipates that alternative airfield deicing 

chemicals will be identified and ultimately incorporated into practice. EPA is aware of one such 

product, Cryotech’s Bio-PDOTM, which is currently being used as an additive for their potassium 

acetate runway product. The Cyrotech BX36 runway product has similar performance to their 

widely-used E36 product, but with reductions in electrical conductivity, reduction in potassium 

content (reducing carbon brake issues), and a bio-based material composition of 75 percent, 

allowing for easy degradation. 

8.3.5 Best Management Practices (BMPs) 

BMPs are techniques used to control stormwater runoff, sediment control, and soil 

stabilization, as well as management decisions to prevent or reduce airport pollution. EPA 

defines a BMP as a "technique, measure or structural control that is used for a given set of 

conditions to manage the quantity and improve the quality of stormwater runoff in the most costeffective manner." This subsection describes the following aircraft/airfield deicing-related 

BMPs: 

• Application rates and deicing fluid dilution; 

• Airfield prewetting; 

• Ice detection systems; 

• Enhanced weather forecasting; 

• Heated sand; 

• Separation of contaminated snow; 

• Annual employee training; 

• Mechanical deicing and snow removal; 

• Yearly inspections of deicing equipment and infrastructure; and 

• Type IV ADF anti-icing. 

Application Rates and Deicing Fluid Dilution 

 Deicing personnel can minimize the amount of deicing fluid used at an airport by varying 

deicing fluid application rates and the ADF dilution mix to best match each deicing event 

condition. Application rates are commonly evaluated every time deicing is required. However, 

ADF is usually pre-mixed to a set 55 percent or 45 percent glycol concentration. Systems that 

allow for ADF dilution adjustment based on the weather conditions can result in less ADF usage. 

Ice thickness, ambient temperatures, and plane size all determine application rates and fluid 

dilution requirements. For small planes with small amounts of frost, as little as 50 gallons of 
Technical Development Document for Proposed Effluent 8. Pollution Prevention and Treatment Technologies 

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July 2009 8-18 

ADF can be used while large planes with thick ice accumulations can take up to 2000 gallons to 

deice. Application rates metered by chemical metering systems installed to deicing trucks or 

booms allow the applicator to control the distribution of chemicals and maintain a consistent 

application rate at all times. Using a chemical metering system also allows the operator to change 

the application rate in the midst of application based on changing weather conditions. 

Airfield Prewetting 

 Airfield prewetting involves applying a dry chemical followed by a light coating of liquid 

deicer to airfield pavement. During icy conditions, a granular deicer is generally used to 

penetrate ice and increase surface area prior to using a liquid deicer (generally propylene glycol) 

to help the solid deicer stick to the pavement and prevent dry pellets from blowing off. EPA’s 

Airport Deicing Questionnaire indicated that prewetting is common and this practice helps to 

minimize the cost of materials by increasing the rate at which the liquid deicer contacts icy 

surfaces and by minimizing wind losses of solid deicer. Following prewetting, snow and ice are 

generally removed from airfield areas using mechanical equipment (such as plows and brooms). 

Ice Detection Systems 

 Ice detection systems include sensors installed on runways and taxiways that transmit 

constant surface and subsurface temperature readings to deicing control personnel. These sensors 

indicate whether there is a potential for ice to form on the paved surfaces. Airports can then use 

the information provided by individual deicer manufacturers to determine whether deicing/antiicing chemicals should be applied. 

Enhanced Weather Forecasting 

 Many of the larger U.S. airports use enhanced weather forecasting systems to help 

determine when they will require deicing activities. A popular weather forecasting product on the 

market is the Weather Support to Deicing Decision Making (WSDDM) software program. This 

system is a “nowcasting” system that is used to confirm National Weather Service data and 

forecasts. WSDDM provides forecasts, monitors storms and provides real-time storm 

information, and estimates and detects precipitation. WSDDM can provide the following 

services to the user: 

• Real-time snow gauge data (updated every minute) of the liquid equivalent 

snowfall rate at the airport and two to three sites 10 to 20 km away from the 

airport; 

• Real-time radar reflectivity from radars depicting current locations of 

precipitation and snow; 

• Meteorological data at the airport and two to three sites 10 to 20 km away from 

the airport updated every minute and displayed in text and time line form, with 

the time line going back to two hours; 

• Thirty-minute nowcast of radar reflectivity based on the use of a cross-correlation 

technique on the radar reflectivity data updated every six minutes; and 

• Thirty-minute nowcast of liquid equivalent snowfall rate at the airport and the offsite snow gauge locations by applying a real-time snow gauge-radar reflectivity 

calibration algorithm at each of the snow gauge sites, updated every six minutes. 
Technical Development Document for Proposed Effluent 8. Pollution Prevention and Treatment Technologies 

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 WSDDM can improve pollution prevention by pinpointing when deicing operations are 

actually needed by lowering the amount of ADFs used to keep departing aircraft free of ice and 

snow contamination at takeoff, and by lowering the amount of anti-icing chemicals used to 

prevent ice and snow from bonding to aircraft and taxiways (ERG, 2005). 

Heated Sand 

 Sand trucks can be parked in a heated garage with heat piped to the truck. Heating sand 

trucks accomplishes two things. First, heating the truck prevents the moisture in the sand from 

freezing and clumping, which would prevent the sand from being efficiently disbursed when 

applied. Second, applying heated sand to icy surfaces can melt ice, which can then refreeze with 

the sand providing needed traction and minimizing the need to use ADFs. 

Separation of Contaminated Snow 

 Airports often segregate glycol-contaminated snow (commonly called “pink snow”) and 

haul it to a designated area where the snow melt can be collected. Deicing pads often contain 

designated areas to store contaminated snow so that the snow melt can be commingled with other 

deicing stormwater. 

Annual Employee Training 

 An important factor affecting the efficiency of aircraft deicing/anti-icing operations is the 

training and experience of personnel performing these operations. Well-trained and experienced 

deicing/anti-icing personnel improve the efficiency of aircraft deicing/anti-icing operations and 

minimize the volume of ADF used. The training and experience of airport personnel may also 

affect the efficiency of airfield deicing operations. Airport personnel are typically responsible for 

clearing taxiways, gate areas, ramps, aprons, and deicing pads. When these areas are not 

adequately cleared, snow and ice accumulate on the undercarriage and the underside of aircraft 

during taxing and must be removed prior to takeoff. 

 Many airports conduct annual operations and maintenance training, with specialized 

winter operations training usually conducted prior to the deicing season. This specialized training 

can include but is not limited to proper use of equipment, application of chemicals, and location 

of snow melt areas. Staff may also be trained in environmental awareness detailing the 

requirements of airport permits and BMPs associated with airport deicing/anti-icing operations. 

Mechanical Deicing and Snow Removal 

 The amount of ADF required to deice aircraft can be minimized by mechanically deicing 

the aircraft prior to chemical deicing. Mechanical deicing is generally economical only for small 

aircraft since mechanical deicing of large aircraft is labor-intensive and time consuming. A 

drawback of mechanical deicing is that aircraft (e.g., aircraft antennae and sensors) risk being 

damaged by incorrect mechanical deicing methods. Despite the risk of aircraft damage, many 

airlines use brooms, squeegees, and ropes, among other items, to remove ice and snow from 

aircraft surfaces. These methods are more effective at removing snow rather than ice. 

 Snow is commonly mechanically removed on airfield pavement, including passenger 

ramps, gate positions, taxiways, and runways, prior to ADF being applied, to prevent 
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contamination of the snow. The following types of equipment are used to remove snow from 

airfield surfaces: self-propelled snow brooms, high speed snow blowers and snow plows, and 

utility trucks or tractors fitted with snow brooms or plows. Physical removal is generally used for 

snow rather than ice. 

Yearly Inspections of Deicing Equipment and Infrastructure 

 Inspections are conducted to ensure that equipment used for deicing operations is 

working properly and to determine where maintenance may be needed. Storage tanks are 

inspected to ensure there are no leaks. ADF application equipment is inspected to determine if 

gauges are working properly and that fluid is not being spilled. Trench or square drains are 

inspected to ensure there is no clogging and that water conveyed through the drain does not 

escape. Other equipment and airport infrastructure may require yearly inspections to make 

certain that deicing chemicals are applied with properly functioning equipment and collected 

with suitable infrastructure. 

Type IV ADF Anti-icing 

 Type IV ADF protects aircraft from ice, snow, or slush accumulations on cleaned aircraft 

surfaces. Type IV fluids form a protective film on treated surfaces, protecting against ice 

formation and/or snow accumulation. Pretreating aircraft with Type IV fluid is an anti-icing 

technique sometimes used when ice is in the forecast and an aircraft is expected to remain on the 

ground for an extended period of time. Applying Type IV ADF anti-icing fluid can reduce the 

amount of deicing fluid needed for an aircraft by reducing the amount of ice that forms on the 

aircraft. 

8.4 References

CASQA. 2003. Vegetated Swale, from “California Stormwater BMP Handbook: Industrial and 

Commercial” (January 1). California Stormwater Quality Association. 

http://www.cabmphandbooks.com/Industrial.asp . 

USEPA. 2008a. Final Engineering Site Visit Report for Minneapolis-St. Paul International 

Airport. U.S. Environmental Protection Agency/Office of Water. Washington, D.C. (January 24). 

DCN AD00793. 

FAA. 2007. Federal Aviation Administration Advisory Circular No. 150/5200-33B. “Hazardous 

Wildlife Attractants on or Near Airports.” (August 28). 

http://www.faa.gov/airports_airtraffic/airports/resources/advisory_circulars/ . 

USEPA. 2007a. Final Engineering Site Visit Report for Seattle - Tacoma International Airport.

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. (July 1). DCN 

AD00778. 

USEPA. 1999. Final Engineering Site Visit Report for Greater Rockford International Airport. 

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. DCN T10402. 
Technical Development Document for Proposed Effluent 8. Pollution Prevention and Treatment Technologies 

Limitation Guidelines and Standards for the Airport Deicing Category Applicable to Airport Deicing Operations 

July 2009 8-21 

ERG. 2007. Memorandum from Juliana Stroup and Mary Willett (ERG) to Brian D’Amico 

(EPA): Aircraft Deicing Stormwater Control Technologies and Their Removal Efficiencies. 

(December 17). DCN AD00855. 

USEPA. 2008b. Final Engineering Site Visit Report for Salt Lake City International Airport. 

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. (January 24). DCN 

AD00792. 

Jungo, E and P. Schob, 2005. “Disposal of De-Icing Effluents by Irrigation” Paper presented at 

International Water Association Leading Edge Conference on Water and Wastewater Treatment 

Technologies, Sapparo, Japan. (6-8 June). DCN AD01200. 

Jungo, E, 2005. “Disposal of De-Icing Effluents by Irrigation; Zurich Airport” PowerPoint 

presentation. (November). DCN AD01199. 

Jacques Whitford NAWE, 2008. “Project: Buffalo Airport” Project Description Sheet. DCN 

AD01186. 

Minkel, K. et. al., 2009. “Innovative Approaches to Managing Stormwater Runoff: Constructed 

Wetlands.” Presentation at FAA 32nd Annual Airport Conference, Hershey PA. (March 4). DCN 

AD01184. 

ERG, 2009. Memorandum from Steve Strackbein and Mary Willett (ERG) to Brian D’Amico 

and Eric Strassler (EPA): Washington Dulles Runway 1L-19R Construction Project Details and 

Update. (June 29). DCN AD01193. 

USEPA. 2006. Final Engineering Site Visit Report for Pittsburgh International Airport. U.S. 

Environmental Protection Agency/Office of Water. Washington, D.C. (November 1). DCN 

AD00774. 

USEPA. 2007b. Final Engineering Site Visit Report for Denver International Airport. U.S. 

Environmental Protection Agency/Office of Water. Washington, D.C. (November 4). DCN 

AD00779. 

FAA. 2005. Federal Aviation Administration Advisory Circular 120-89. “Ground De-Icing using 

Infrared Energy.” (December 13). 

Radiant Aviation. 2008. Radiant Infrared Aircraft Deicing Systems. Product Flyer. DCN 

AD01198. 

ERG. 2004. Aircraft Deicing using an Infrared System called Ice-Cat. (December 13). DCN 

AD00095. 

Becher-Hoppe Associates, Inc. 2004. Airport Facilities - Rhinelande -Oneida County Airport. 

(December 6). DCN AD00097. 

Icewolf. The Evolution of Aircraft Deicing Systems, Icewolf, Product Flyer. DCN AD00096. 
Technical Development Document for Proposed Effluent 8. Pollution Prevention and Treatment Technologies 

Limitation Guidelines and Standards for the Airport Deicing Category Applicable to Airport Deicing Operations 

July 2009 8-22 

IDS. 2006. Deicing the IDS Way, Product Flyer (January 4). Integrated Deicing Services. DCN 

D00077. 

ERG. 2005. Memorandum from Steve Strackbein (ERG) to Project File: Summary of Weather 

Support to Deicing Decision Making (WSDDM): A Winter Weather Nowcasting System.

(January 3). DCN AD00185. 
Technical Development Document for Proposed Effluent 9. Control and Treatment Performance 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 9-1 

9. CONTROL AND TREATMENT PERFORMANCE 

 This section describes the control and treatment scenarios that EPA evaluated for the 

proposed airport deicing rulemaking. Each scenario is comprised of groups of ADF collection 

activities and a wastewater treatment technology identified to reduce or eliminate the discharge 

of pollutants from airports. EPA identified these technologies from technical literature (including 

case studies and previous rulemaking efforts), responses to EPA airport and airline surveys, and 

EPA site visits and sampling episodes. 

 The Agency does not require sites to implement these specific activities and technologies 

to comply with the proposed rulemaking; sites can implement any technology (or completely 

eliminate their discharge through contract hauling or recycling) as long as they achieve the 

proposed effluent limitations. 

 Section 9.1 summarizes the criteria EPA used in selecting the proposed control and 

treatment scenarios and Section 9.2 describes the performance efficiencies achieved by those 

scenarios. Sections 9.3 and 9.4 describe the development of the long-term mean concentrations 

for chemical oxygen demand (COD) and ammonia, respectively, using long-term performance 

data from Albany International (ALB) airport. 

9.1 Development of Proposed Control and Treatment Scenarios

 EPA reviewed several different ADF-contaminated stormwater control and treatment 

technologies, as described in Section 8. These technologies were assessed against the following 

criteria to determine those technologies to be considered for proposal: 

• Their ability to collect and contain ADF-contaminated stormwater; 

• The prevalence of their use by the aviation industry; 

• Engineering aspects of the technology affecting its ease of use; and 

• Their ability to reduce pollutant loadings. 

 Based on its evaluation, EPA identified three ADF-contaminated stormwater collection 

technologies and one stormwater treatment technology for further evaluation and incorporation 

into the proposal options. The collection technologies identified included glycol recovery 

vehicles (GRVs), GRVs in combination with plug and pump systems, and deicing pads. The 

treatment technology identified for evaluation was anaerobic fluidized bed (AFB) biological 

treatment. There are also several recycle and recovery alternatives capable of achieving effective 

pollutant reductions. These technologies are described below along with the reasons for their 

selection. 

9.1.1 GRVs 

 As described in Section 8.1.1, GRVs collect spent aircraft and airfield deicing fluids as 

well as any slush or snow from gate areas, ramps, aircraft parking areas, taxiways, and aircraft 

holding pads. The GRV is a high-airflow, wide-sweep-path vacuum used to efficiently collect 

and separate glycol and ice. This technology works most efficiently when it is used to collect 

runoff soon after deicing is completed and with as little dilution as possible from direct 

precipitation and nondeicing runoff. EPA selected GRVs for further evaluation since they are 

commonly used by airports now for deicing stormwater collection, can be used at both the gate 
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July 2009 9-2 

and centralized deicing locations, can collect deicing stormwater at the point of generation, and 

represent a low-cost collection technology that does not require infrastructure changes. 

 Limitations noted in using GRVs include the following: potential problems with ponding 

of deicing stormwater during heavy precipitation, added vehicular traffic in congested gate areas, 

irregular ground surfaces undermining collection effectiveness, and slush clogging the collection 

systems under heavy snow conditions. 

9.1.2 GRVs in Combination with Plug and Pump Systems 

 Plug and pump systems intercept and temporarily hold deicing-contaminated stormwater 

close to the source using existing storm sewers. Plug and pump systems are often supplemented 

with GRVs. Drainage blocks, consisting of valves or inflatable plugs, are installed within the 

existing drains to prevent concentrated deicing storm water from entering the drainage system 

and discharging to surface water. Deicing stormwater is then collected using pumps or GRVs, 

and transported elsewhere for treatment or processing. Blocking mechanisms can be opened or 

removed during non-deicing periods to allow uncontaminated stormwater to drain normally. 

EPA selected GRVs in combination with plug and pump systems for further evaluation since 

they are well documented as a collection technology at many airports, allow deicing stormwater 

to be collected at the gate, and involve minimal infrastructure changes compared to other types 

of collection technologies. 

 An alternative to the plug and pump system is installing diversion equipment (e.g. 

diversion valves) within the airport’s existing stormwater drainage system. In a stormwater 

diversion system, the stormwater is routed to storage prior to treatment or discharge, instead of 

being blocked from drainage areas. A well-operated diversion system, operating in combination 

with GRVs, can be considered an equivalent technology to a plug and pump system with GRVs. 

9.1.3 Deicing Pads 

 Centralized deicing pads restrict aircraft deicing to a controlled, confined area, 

minimizing the volume of fugitive spent deicing fluid and allowing the deicing waste to be 

captured. A deicing pad is specially graded to capture and route contaminated runoff to tanks. If 

the pads are located near gate areas or at the heads of runways, planes can be deiced just prior to 

takeoff; as a result, less Type IV anti-icing fluid may be necessary for shorter holdover times, 

reducing the amount of glycols released onto the runway or into the air. The goal is to 

concentrate aircraft deicing activity in a centralized location to minimize containment areas and 

runoff volumes and maximize concentrations of deicers in that runoff. EPA selected deicing pads 

for further evaluation since they represent state-of-the-art for spent deicing fluid collection and 

can significantly reduce the amount of deicing stormwater generated, increase the amount of 

concentrated deicing stormwater collected, and therefore create additional opportunities for costeffective recycle and recovery operations. 

9.1.4 AFB Biological Treatment 

 AFB biological treatment is a demonstrated technology for treating ADF-contaminated 

stormwater. This treatment technology is currently used at two airports, the ALB airport and 

Akron–Canton Regional (CAK) airport, and is planned for at least one additional airport in the 

near future. The AFB treatment system uses a vertical, cylindrical tank in which the ADF-
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July 2009 9-3 

contaminated stormwater is pumped upwards through a bed of granular activated carbon at a 

velocity sufficient to fluidize, or suspend, the media. A thin film of microorganisms grows and 

coats each granular activated carbon particle, providing a vast surface area for biological growth. 

The anaerobic microorganisms that develop occur naturally in sediment, peat bogs, cattle 

intestines, and even brewer's yeast. These microorganisms provide treatment of the ADFcontaminated stormwater. AFB treatment system by-products include methane, carbon dioxide, 

and new biomass. Effluent from the AFB can be discharged to a local POTW or, in most cases, 

directly to surface water. 

 Treating wastes using an anaerobic biological system as compared to an aerobic system 

offers several advantages. The anaerobic system requires less energy since aeration is not 

required and the anaerobic system produces less than 10 percent of the sludge of an aerobic 

process. In addition, because the biological process is contained in a sealed reactor, odors are 

eliminated. EPA selected AFB biological treatment for further evaluation since it represents the 

best technology currently in use by airports to treat deicing stormwater prior to direct discharge. 

9.1.5 Recycle/Recovery Operations 

 Recycling and recovery operations for spent ADF may, in some cases, be able to achieve 

pollutant reductions equivalent to AFB treatment and could perform as alternative technologies 

to AFB. Two of these technologies, which EPA evaluated in its sampling program, include 

mechanical vapor recompression (MVR) followed by distillation used at the Denver 

International (DEN) airport and ultrafiltration (UF)/ reverse osmosis (RO) used at the Pittsburgh 

International (PIT) airport. The systems EPA evaluated are both used prior to indirect discharge 

and have not been demonstrated to sufficiently treat ADF-contaminated stormwater prior to 

direct discharge. Both of these systems are discussed below. 

 MVR followed by distillation is a demonstrated system used to recycle and recover spent 

ADF. The system is typically used when glycol concentrations in ADF-contaminated stormwater 

are greater than 5 percent; this type of a system is not generally practical for lower concentration 

glycol-contaminated stormwater, which would typically be discharged to a POTW for treatment. 

The MVR/distillation technology generates a concentrated glycol stream (containing greater than 

99 percent glycol) that can be sold as a chemical feedstock. The effluents from the 

MVR/distillation system contain propylene glycol, carbonaceous BOD (cBOD), and COD, and 

must be discharged to a POTW for further treatment. 

 UF/RO technology is also a demonstrated recycle and recovery system for spent ADF. 

The technology generates a concentrated glycol stream that can be recovered and contract hauled 

off site for resale as a chemical feedstock or recycled for possible use in toilets onboard 

commercial aircraft (i.e., as lavatory fluid). The effluent from the UF/RO system contains small 

amounts of glycol, cBOD, and COD and can either be discharged to surface water or to a POTW 

for further processing. 

9.2 Performance of Control and Treatment Scenarios

 EPA evaluated the performance of the selected control and treatment scenarios based on 

their ability to collect and contain ADF-contaminated stormwater and/or their ability to reduce 
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July 2009 9-4 

pollutant loadings. The performance data used to assess the technology effectiveness include 

both EPA-collected data and industry-submitted data. 

9.2.1 GRV Collection (20 Percent Efficiency Scenario) 

 EPA identified performance data on GRVs from several airports. The Gerald R. Ford 

International (GRR) airport (Grand Rapids, MI) system, which is based on using two tow-behind 

glycol collection units in conjunction with catch basin inserts to collect aircraft deicing runoff 

around the terminal gates and apron, reported collecting 29 percent of all applied glycol during 

the 2005/2006 deicing season. Mass balance data on glycol usage and collection at Theodore 

Francis Green State (PVD) airport (Providence, RI) between 2002 and 2006 indicate that its 

glycol-collection-vehicle-based system annually collects between 26 and 48 percent of all 

applied glycol. At Milwaukee’s General Mitchell International (MKE) airport, a system that 

combines mobile glycol collection with a plug and pump approach using in-line sewer valves 

and balloons around the terminal apron collected between 22.5 and 33 percent of all applied 

glycol in the deicing seasons between 2002 and 2006. At Buffalo Niagara International (BUF) 

airport, a system consisting of two glycol collection vehicles operating at the gates combined 

with an apron collection system and effective snow management allowed the airport to collect 

approximately 53 percent of applied glycol. (ERG, 2007) Overall, collection efficiencies of 

applied glycol from these airports ranged from 22.5 to 53 percent, although these systems also 

used some combination of catch basin inserts, plug and pump technology, and/or apron systems. 

 Data summarized in the Transportation Research Board (TRB) Airport Cooperative 

Research Program Report No. 14, Deicing Planning Guidelines and Practices for Stormwater 

Management Systems reported collection efficiencies between 23 – 48 percent for glycol 

collection vehicles. (TRB Airport Cooperative Research Program, 2009) Based on these data, 

EPA estimates that GRVs alone recover 20 percent of applied glycol. 

9.2.2 Plug and pump Collection (40 Percent Efficiency Scenario) 

 For many airports, a plug and pump system can be easily deployed and operational in a 

short timeframe. Data summarized in the Transportation Research Board (TRB) Airport 

Cooperative Research Program Report No. 14, Deicing Planning Guidelines and Practices for 

Stormwater Management Systems reported collection efficiencies between 20 – 35 percent for 

plug and pump systems. (TRB Air Cooperative Research Program, 2009) Plug and pump 

systems typically enhance the effectiveness of a GRV collection system; therefore, EPA assumed 

that facilities effectively operating a plug and pump system in combination with GRV collection 

systems recover 40 percent of applied glycol. 

9.2.3 Deicing Pad Collection (60 Percent Efficiency Scenario) 

 EPA reviewed data on the performance of centralized deicing facilities from a number of 

larger airports across the United States and Europe. PIT airport observed collection efficiencies 

at the centralized deicing pads of between 60 and 66 percent over the varying winter seasons 

(CDM, 2006). Analysis of 10 years of records of ADF usage, glycol collection, glycol recycling, 

and discharges to the POTW for the DEN airport’s deicing runoff control program indicates an 

average annual collection efficiency of 64 percent of applied glycols, ranging between 44 and 70 

percent annually (Denver International Airport, 2006). Analysis of daily mass balance 

monitoring data collected between 1999 and 2006 at the Detroit Metropolitan Wayne County 
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Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 9-5 

(DTW) airport indicates that the central deicing facility-based program recycled 45 to 51 percent 

of applied glycol. Additional glycol at lower concentrations is captured and sent to POTW 

treatment, but the monitoring program design does not support estimation of this fraction. The 

collection efficiencies reviewed from U.S. airports was consistent with information on European 

airports. Aha et al., reported collection of applied glycol at European airports ranging from 80 

percent at Oslo Airport to 51 percent at Munich. (Aha, et. al, 2005a, Aha, et. al., 2005b) 

Additionally, Baltimore-Washington International (BWI) airport operates a deicing runoff 

control system that uses central deicing pads coupled with limited at-gate deicing, isolation and 

containment using trench drains and glycol recovery vehicles, and management of contaminated 

snow from the designated deicing areas. Between 1998 and 2006, glycol recovery ranged from 

59 to 86 percent of total glycol applied, and averaged 69 percent (Williams, 2006). 

 Overall, collection efficiencies at centralized deicing pads from these airports and as 

reported in the Transportation Research Board (TRB) Airport Cooperative Research Program 

Report No. 14, ranged from 44 to 86 percent of applied glycol. (TRB Air Cooperative Research 

Program, 2009) Several airports reported a relatively consistent efficiency of around 60 to 66 

percent over the varying winter seasons. Based on this information, EPA estimates that facilities 

effectively operating a centralized deicing pad recover 60 percent of applied glycol. 

9.2.4 AFB Treatment Performance 

 EPA collected data on the effectiveness of AFB treatment systems through literature 

review, its own sampling efforts, and industry-supplied data. These systems have demonstrated 

effective treatment for targeted pollutants, including COD, biochemical oxygen demand (BOD5), 

and glycol. Based on EPA’s sampling data from ALB airport, COD was reduced by greater than 

97 percent, BOD5 was reduced by greater than 98 percent, and glycol was reduced by greater 

than 99 percent (ERG, 2007). 

9.3 References

ERG. 2007. Memorandum from Juliana Stroup and Mary Willett (ERG) to Brian D’Amico 

(EPA): Aircraft Deicing Stormwater Control Technologies and Their Removal Efficiencies. 

(December 17). DCN AD00855. 

TRB Airport Cooperative Research Program, 2009. Deicing Planning Guidelines and Practices 

for Stormwater Management Systems ACRP Report No. 14. DCN AD01191. 

CDM. 2006. 2006 Deicing Action Plan Update - Pittsburgh International Airport (Excerpts). 

Denver International Airport 2006. Design Standards Manual, Aircraft Deicing - DRAFT. 

Aha, S. et al. 2005a. Munich Airport Trip Report: USA. 

Aha, S., et al. 2005b. Oslo Airport Trip Report. 

Williams, M. 2006. Baltimore-Washington International Airport Deicing Mass Balance. 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-1 

10. POLLUTANT LOADINGS AND POLLUTANT LOAD REDUCTION ESTIMATES

 Pollutant loadings from airport deicing operations are highly variable and airportspecific. Because the use of deicing and anti-icing chemicals is weather-dependent, the pollutant 

loadings at each airport vary from year to year based on weather conditions; the pollutant 

loadings also vary from airport to airport based on each airport’s climate. In addition, the amount 

of applied chemical that is discharged to surface water is airport-specific, based on the existing 

stormwater separation, collection, and/or containment system present at each airport. 

 Due to the variations of the pollutant discharges, EPA determined that it would not be 

appropriate to develop baseline pollutant loadings using end-of-pipe monitoring data. Monitoring 

data on an airport’s deicing stormwater outfall(s) provide only a “snap shot” of a single point in 

time, during a monthly monitoring event or, in some cases, a single storm event. In addition, 

these data are available only for a select number of airports and are airport-specific. Although 

these data provide information on the types of pollutants present in airport deicing stormwater 

and the range of concentrations that may reach outfall points, there is insufficient basis for 

extrapolating or transferring the data across large timeframes (e.g., an entire winter season) or to 

other airports. 

 Therefore, EPA developed a pollutant loading estimation methodology based on the use 

of aircraft deicing/anti-icing fluid (ADF) and airfield chemicals at the airports surveyed by EPA. 

The methodology takes into account EPA’s existing data sources and will provide a better 

estimate of the loadings than those based on sporadic monitoring data alone. This section 

discusses the data sources available to EPA to support its pollutant loadings and loading 

reduction estimates (Section 10.1), an overview of EPA’s pollutant loading methodology 

(Section 10.2), and a summary of the calculation steps that make up EPA’s loading methodology 

(Sections 10.3 through 10.6). Section 10.7 summarizes EPA’s approach for estimating loading 

reductions associated with the discontinued use of urea as an airfield deicing chemical. 

10.1 Data Sources

 EPA considered the following available data when developing a pollutant loadings 

estimation methodology for airport deicing operations (see Section 4 for more information about 

the data sources): 

• Pavement deicing chemical usage/purchase information for the 2002/2003, 

2003/2004, and 2004/2005 deicing seasons, as reported by airport personnel in the 

airport questionnaire; 

• ADF purchase information for the 2002/2003, 2003/2004, and 2004/2005 deicing 

seasons, as reported by airline personnel in the airline detailed questionnaire; 

• Standard airport information available from the Federal Aviation Administration 

(FAA), including the number of operations and departures by airport; 

• Weather information for each airport from National Oceanic and Atmospheric 

Administration (NOAA), including temperature, freezing precipitation, and 

snowfall data; 

• Existing airport stormwater collection and containment systems, as reported by 

airport personnel in the airport questionnaire or during EPA site visits; 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-2 

• Standard chemical information about ADF and pavement deicing chemicals, 

including molecular formulas and densities; and 

• Analytical data from EPA sampling episodes of airport deicing operations. 

10.2 Pollutant Loadings Methodology Overview

 EPA developed the following methodology to estimate pollutant loadings based on the 

available data listed above: 

• Step 1: Estimate the amount of ADF and pavement deicing chemicals applied at 

each airport during a typical winter season; 

• Step 2: Calculate the amount of pollutant load associated with the applied 

chemicals, based on the chemical properties of the chemicals; 

• Step 3: Estimate the amount of the applied chemical’s pollutant load that is 

discharged directly, based on the airport’s existing stormwater collection, 

containment and/or treatment system; and 

• Step 4: Estimate pollutant loading removals for each EPA control/treatment 

scenario. 

 The subsections below describe each step in detail. 

10.3 Step 1: Estimate the Amount of Applied ADF and Pavement Deicing 

Chemicals

 To develop pollutant loadings estimates associated with airport deicing operations, EPA 

first estimated the amount of applied pavement deicing chemicals and ADF based on data 

collected in EPA’s airport and airline detailed questionnaires. EPA requested data on three 

winter seasons (2002/2003, 2003/2004, and 2004/2005); these data were averaged for each 

airport to account for any variability in the severity of the winter weather over those three years. 

In the airport questionnaire, EPA requested usage data for pavement deicing chemicals. In the 

airline screener and detailed questionnaires, EPA requested ADF purchase data instead of usage 

data. During the airline questionnaire development process, airport and airline personnel reported 

to EPA that purchase data are documented and tracked more frequently than usage data and are a 

good indicator of the amount of chemical used because operations do not stockpile the chemicals 

from year to year. The reported amount of chemical purchased was used as a surrogate for the 

amount of chemical applied. 

 EPA sent the airport questionnaire to 153 airports, which were selected using a stratified 

random sample of airports based on airport type (i.e., hub, non-hub), the number of snow or 

freezing precipitation (SOFP) days, and the number of departures. For more information about 

the airport questionnaire, see Section 4.3. 

 The airline questionnaire collected information from 58 airlines that indicated in their 

screener questionnaire that plane deicing was conducted on their aircraft. These 58 airlines 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-3 

represent 448 airline/airport combinations. For more information about the airline questionnaire, 

see Section 4.3. 

10.3.1 Pavement Deicing and Pavement Anti-Icing Chemical Usage Estimate 

 In the airport questionnaire, EPA requested that airport personnel report the 

purchase/usage amount, concentration, and brand name of the following pavement deicing 

materials for the 2002/2003, 2003/2004, and 2004/2005 deicing seasons: 

• Urea; 

• Potassium Acetate; 

• Calcium Magnesium Acetate (CMA); 

• Sodium Acetate; 

• Sand; 

• Sodium Formate; 

• Ethylene Glycol-Based Fluids; 

• Propylene Glycol-Based Fluids; and 

• Other: (Specify). 

 EPA evaluated the data provided for each reported chemical to determine the most 

appropriate way to estimate the average amount used over the three winter seasons reported. In 

addition, EPA read the comments provided by the airport personnel to determine any extenuating 

circumstances that affect chemical use. For example, airport personnel may have reported that 

urea was replaced with potassium acetate at the airport during the three years reported. In this 

case, EPA used the potassium acetate average in the loadings estimate and did not use any of the 

urea data to better represent the airport’s current practices. Ninety airports reported pavement 

deicing chemical usage values to EPA in their questionnaire responses. 

 The three-year average pavement deicing chemical usage EPA calculated from the 

reported data (normalized to pure chemical) is shown by airport and chemical in Table 10-1. In 

the questionnaire, airports reported pounds or gallons of pavement deicing chemical used along 

with the concentration of the chemical. EPA calculated the amount of applied chemical by 

multiplying the reported mass of each chemical by the reported concentration. If airport 

personnel reported a volume of chemical in the airport or airline detailed questionnaire, EPA 

multiplied the reported volume by the reported concentration and the chemical density. 

 No airports reported the use of CMA. Multiple airports reported the use of sand, but these 

data are not included in Table 10-1, because sand was not included in the loads analysis. Only 

one airport reported the use of granular potassium acetate. Potassium acetate (in the liquid form) 

is the most commonly used pavement deicing chemical. 
10-4 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category PollutanSource: Airport Deicing Operations Loads Database (USEPA, 2008a). July 2009 

Table 10-1. Three-Year Average Amount of Pavement Deicing Chemical Usage, in Poun

Airport 

ID Airport Name 

Ethylene 

GlycolBased Fluids

Granular 

Potassium 

Acetate 

Potassium 

Acetate 

Sodium 

Acetate 

Sodium 

Formate 

P

Ba

1006 Chicago O'Hare International 0 0 272,987 0 0 61007 Yeager 0 0 0 2,560 0 1010 Fairbanks International 0 0 218,896 0 0 1011 Lambert - St Louis International 0 0 5,822,755 0 0 1012 Ted Stevens Anchorage International 0 0 1,015,403 0 0 1013 Wiley Post-Will Rogers Mem 0 0 0 0 0 1014 Albuquerque International Sunport 0 0 4,586 0 0 1016 Tri - State/Milton J Ferguson Field 0 0 27,089 0 0 1017 Austin Straubel International 0 0 38,121 0 0 1018 Piedmont Triad International 0 0 57,869 0 0 1020 Hartsfield - Jackson Atlanta 

International 

0 0 314,456 0 0 

1021 Buffalo Niagara International 0 0 0 0 7,760 1022 Fort Wayne International 0 0 248,180 0 0 1023 Seattle - Tacoma International 0 0 97,914 696 0 1024 Indianapolis International 0 0 839,922 506,000 0 1026 Dallas/Fort Worth International 0 0 18,179 0 0 1028 Denver International 0 0 3,350,089 0 0 1029 La Guardia 0 0 1,062,816 1,747 0 1031 Richmond International 0 0 245,463 17,000 0 1032 Austin - Bergstrom International 0 0 17,483 0 0 1036 Baltimore - Washington International 0 0 1,151,158 306,560 156,800 1041 Glacier Park International 0 0 0 0 0 1043 Ralph Wien Memorial 0 0 39,525 0 0 1044 Roanoke Regional/Woodrum Field 0 0 131,536 0 0 1050 Aspen - Pitkin County/Sardy Field 0 20,333 46,732 0 0 1052 Wilmington International 0 0 0 0 0 
10-5 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category Pollutan

Table 10-1 (Continued) 

Source: Airport Deicing Operations Loads Database (USEPA, 2008a). July 2009 

Airport 

ID Airport Name 

Ethylene 

GlycolBased Fluids

Granular 

Potassium 

Acetate 

Potassium 

Acetate 

Sodium 

Acetate 

Sodium 

Formate 

P

Ba

1053 General Edward Lawrence Logan 

International 

1,045,791 0 0 0 0 

1057 Will Rogers World 0 0 42,583 2,910 0 1058 Gerald R Ford International 0 0 62,433 0 4,975 1059 Greater Rochester International 0 0 298,335 0 0 1063 Evansville Regional 0 0 28,825 0 0 1065 Albany International 0 0 196,535 150,000 0 1066 Salt Lake City International 0 0 255,058 0 0 1068 Eppley Airfield 0 0 250,525 4,527 0 1069 Cleveland - Hopkins International 0 0 2,947,968 196,438 6,247 1070 City of Colorado Springs Municipal 0 0 198,504 0 0 1071 Tweed - New Haven 0 0 0 291 0 1074 South Bend Regional 0 0 0 0 0 1078 Nashville International 0 0 163,779 0 0 1079 Manchester 0 0 318,109 0 0 1080 Syracuse Hancock International 0 0 11,792 0 0 1082 Trenton Mercer 0 0 12,393 0 4,704 1084 Bismarck Municipal 0 0 16,114 0 0 1085 Waterloo Municipal 0 0 0 0 0 1088 Outagamie County Regional 0 0 229,290 0 0 1089 John F Kennedy International 0 0 167,054 3,812,682 0 1090 Boise Air Terminal/Gowen Field 0 0 127,865 0 0 1094 Boeing Field/King County International 0 0 10,255 0 0 1095 Chicago Midway International 0 0 1,259,838 0 0 1098 Aberdeen Regional 0 0 21,857 0 0 1100 Toledo Express 0 0 196,535 0 0 1101 Portland International 0 0 256,478 10,292 211,183 
10-6 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category Pollutan

Table 10-1 (Continued) 

Source: Airport Deicing Operations Loads Database (USEPA, 2008a). July 2009 

Airport 

ID Airport Name 

Ethylene 

GlycolBased Fluids

Granular 

Potassium 

Acetate 

Potassium 

Acetate 

Sodium 

Acetate 

Sodium 

Formate 

P

Ba

1103 Juneau International 0 0 0 0 0 1104 Nome 0 0 39,307 0 0 1105 Spokane International 0 0 240 0 0 1107 Pittsburgh International 0 0 1,550,440 13,333 111,067 1108 Louisville International - Standiford 

Field 

0 0 747,299 0 109,760 

1109 Airborne Airpark 0 0 1,841,386 0 1,354,767 1110 Aniak 0 0 0 0 1111 Port Columbus International 0 0 548,790 0 6,226 1112 Deadhorse 0 0 14,413 0 0 1113 Cincinnati/Northern Kentucky 

International 

0 0 2,655,839 0 4,000 

1114 Stewart International 0 0 78,614 2,520 0 1116 Reno/Tahoe International 0 0 26,205 0 0 1117 Cherry Capital 0 0 63,474 0 0 1118 Bethel 0 0 0 0 0 1119 Rickenbacker International 0 0 72,849 0 23,520 1120 Rapid City Regional 0 0 0 0 0 1121 Theodore Francis Green State 0 0 141,287 0 0 1123 James M Cox Dayton International 0 0 151,917 0 0 1124 Des Moines International 0 0 211,821 81,157 0 1126 Minneapolis - St Paul 

International/Wold - Chamberlain 

0 0 1,117,715 64,667 0 

1128 Charlotte/Douglas International 0 0 109,356 0 0 1129 Bradley International 0 0 481,947 218,817 0 1136 General Mitchell International 0 0 1,199,246 0 127,400 1137 Dallas Love Field 0 0 218 0 0 
10-7 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category Pollutan

Table 10-1 (Continued) 

Source: Airport Deicing Operations Loads Database (USEPA, 2008a). July 2009 

Airport 

ID Airport Name 

Ethylene 

GlycolBased Fluids

Granular 

Potassium 

Acetate 

Potassium 

Acetate 

Sodium 

Acetate 

Sodium 

Formate 

P

Ba

1138 Detroit Metropolitan Wayne County 0 0 1,771,433 0 0 1139 Philadelphia International 0 0 0 0 0 11140 Memphis International 0 0 496,699 74,325 0 1141 Ronald Reagan Washington National 0 0 353,544 45,667 0 1142 Washington Dulles International 0 0 2,823,474 617,580 0 1144 Central Wisconsin 1,858 0 58,674 0 0 1145 Newark Liberty International 0 0 2,945,968 7,760 0 1146 Northwest Arkansas Regional 264,162 0 0 0 0 1147 Raleigh - Durham International 0 0 0 0 0 1148 Kansas City International 0 0 604,017 3,267 0 1149 Fort Worth Alliance 0 0 5,241 0 0 1150 Greater Rockford 0 0 339,913 0 0 1151 Kalamazoo/Battle Creek International 0 0 0 4,000 0 1153 Akron - Canton Regional 0 0 19,494 162 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-8 

10.3.2 ADF Usage Estimate 

 EPA requested the purchase amount, concentration, and brand name in the airline 

detailed questionnaire for the 2002/2003, 2003/2004, and 2004/2005 deicing seasons for the 

following ADF chemicals: 

• Type I Ethylene Glycol-Based Fluid (EG Type I); 

• Type II Ethylene Glycol-Based Fluid (EG Type II); 

• Type IV Ethylene Glycol-Based Fluid (EG Type IV); 

• Type I Propylene Glycol-Based Fluid (PG Type I); 

• Type II Propylene Glycol-Based Fluid (PG Type II); 

• Type III Propylene Glycol-Based Fluid (PG Type III); 

• Type IV Propylene Glycol-Based Fluid (PG Type IV); and 

• Isopropyl Alcohol-Based Fluid. 

 Questionnaire responses provided sufficient data to estimate ADF usage at 56 airports. In 

some cases, data were not available for every airline operating at an airport. In these instances, 

EPA extrapolated the amount of ADF used at the reporting airlines to estimate the total amount 

of ADF used by the entire airport, based on the number of airport operations (departures) at the 

reporting airlines and the total amount of airport operations. Table 10-2 presents the ADF 

estimates based on airline questionnaire responses. No airports reported the purchase of EG 

Type II, EG Type III, PG Type II, PG Type III, or Isopropyl Alcohol-Based Fluid. 

 In addition to the ADF data reported in the airline detailed questionnaire, 10 airports 

reported their estimate of total annual ADF usage to EPA in the comment section of the airport 

questionnaire (see Table 10-3). These ADF data were combined with the ADF data reported in 

the airline detailed questionnaires, resulting in 66 airports with total PG/EG (gallons) usage 

estimates. 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008b). 

Note: PG/EG gallons represent total usage normalized to 100 percent glycol. Values may not sum to 100 due to 

rounding. 

GPY – Gallons per year. 

July 2009 10-9 

Table 10-2. ADF Estimates Based on Airline Detailed Questionnaire Responses 

Airport 

ID Airport Name 

Estimated 

PG/EG 

(GPY) 

PG 

Type I 

(%) 

PG 

Type IV 

(%) 

EG 

Type 1 

(%) 

EG 

Type IV 

(%) 

1003 Ketchikan International 18,182 0 0 100 0 

1006 Chicago O'Hare International 1,516,626 80 20 0 0 

1010 Fairbanks International 83,335 0 0 100 0 

1011 Lambert - St Louis International 325,122 23 1 70 6 

1012 Ted Stevens Anchorage International 420,735 0 0 100 0 

1013 Wiley Post-Will Rogers Mem 3,056 9 0 91 0 

1021 Buffalo Niagara International 281,836 92 9 0 0 

1022 Fort Wayne International 50,412 92 8 0 0 

1024 Indianapolis International 452,155 91 9 0 0 

1026 Dallas/Fort Worth International 166,790 43 12 38 7 

1028 Denver International 1,043,138 87 10 4 0 

1029 La Guardia 485,157 75 22 2 1 

1036 Baltimore - Washington 

International 

323,623 90 10 0 0 

1037 George Bush Intercontinental 

Airport/Houston 

10,242 82 18 0 0 

1043 Ralph Wien Memorial 2,500 27 0 73 0 

1047 Sacramento Mather 1,282 100 0 0 0 

1053 General Edward Lawrence Logan 

International 

995,249 82 17 0 0 

1058 Gerald R Ford International 98,156 86 13 0 0 

1059 Greater Rochester International 229,158 91 9 0 0 

1065 Albany International 125,775 93 7 0 0 

1066 Salt Lake City International 570,540 22 6 52 20 

1069 Cleveland - Hopkins International 582,321 90 10 0 0 

1074 South Bend Regional 29,586 75 25 0 0 

1079 Manchester 177,307 87 13 0 0 

1080 Syracuse Hancock International 186,351 97 3 0 0 

1089 John F Kennedy International 560,031 82 18 0 0 

1095 Chicago Midway International 293,834 88 12 0 0 

1100 Toledo Express 46,449 64 5 29 2 

1103 Juneau International 48,014 0 0 100 0 

1104 Nome 3,047 15 0 85 0 

1105 Spokane International 67,984 92 8 0 0 

1107 Pittsburgh International 943,982 88 12 0 0 

1109 Airborne Airpark 432,416 74 26 0 0 

1110 Aniak 476 100 0 0 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-2 (Continued) 

Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008b). 

Note: PG/EG gallons represent total usage normalized to 100 percent glycol. Values may not sum to 100 due to 

rounding. 

GPY – Gallons per year. 

July 2009 10-10 

Airport 

ID Airport Name 

Estimated 

PG/EG 

(GPY) 

PG 

Type I 

(%) 

PG 

Type IV 

(%) 

EG 

Type 1 

(%) 

EG 

Type IV 

(%) 

1111 Port Columbus International 288,374 92 8 0 0 

1113 Cincinnati/Northern Kentucky 

International 

715,836 24 5 61 11 

1117 Cherry Capital 11,524 75 0 0 25 

1118 Bethel 4,897 40 0 60 0 

1123 James M Cox Dayton International 90,580 89 11 0 0 

1124 Des Moines International 79,658 84 14 3 0 

1126 Minneapolis - St Paul 

International/Wold - Chamberlain 

1,456,537 93 7 0 0 

1128 Charlotte/Douglas International 143,572 81 19 0 0 

1129 Bradley International 427,068 88 12 0 0 

1136 General Mitchell International 152,944 90 9 0 1 

1138 Detroit Metropolitan Wayne County 2,152,292 93 7 0 0 

1139 Philadelphia International 979,983 88 12 0 0 

1140 Memphis International 199,174 88 12 0 0 

1141 Ronald Reagan Washington National 219,533 81 16 3 0 

1142 Washington Dulles International 1,076,083 77 22 1 0 

1145 Newark Liberty International 1,123,057 86 14 0 0 

1148 Kansas City International 203,726 75 8 17 0 

1149 Fort Worth Alliance 1,522 97 3 0 0 

1150 Greater Rockford 146,856 79 21 0 0 

1151 Kalamazoo/Battle Creek 

International 

22,002 84 16 0 0 

1152 Duluth International 68,168 96 4 0 0 

1153 Akron - Canton Regional 60,246 90 10 0 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-3. ADF Data Reported in the Airport Questionnaire 

Airport ID Airport Name PG/EG (GPY) 

1115 Jacksonville International 1,000 

1062 Birmingham International 5,000 

1072 Gillette-Campbell County 880 

1060 Williamson County Regional 150 

1096 Santa Fe Municipal 1,108 

1097 Lovell Field 4,148 

1025 Tupelo Regional 820 

1143 San Francisco International 105 

1001 Montgomery Regional (Dannelly Field) 232 

1019 Ontario International 35 

Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008b). 

GPY – Gallons per year. 

 Using the airline and airport questionnaire data on ADF purchases, airport departure data, 

and climate data, EPA correlated the estimate of the amount of ADF used to the climate and size 

of each airport. EPA created an “ADF Factor” to estimate the relative amount of deicing 

occurring at each airport based on the airport’s climate and number of departures. EPA 

calculated the ADF Factor by multiplying the 30-year annual average number of SOFP days by 

the average number of annual departures at each airport during 2004-2006 (USEPA, 2008b). 

EPA graphed the total gallons of PG/EG purchased with the ADF factor and determined the 

equation of the line. During this analysis, EPA noted a difference in the relationship of ADF 

Factor and ADF usage for Alaskan airports compared to other airports. Due to this difference, 

EPA developed a separate graph and equation for Alaskan airports. The graph for non-Alaskan 

airports is presented in Figure 10-1; the graph for Alaskan airports is presented in Figure 10-2. 

y = 0.3073x

R2 = 0.7622

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

0 2,000,000 4,000,000 6,000,000 8,000,000

ADF Factor (SOFP Days x Average Annual Departures)

PG/EG 

Gallons 

per Year

Figure 10-1. ADF Factor vs. PG/EG Gallons for U.S. Airports (excluding Alaska) 

July 2009 10-11 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

y = 0.0632x

R2

 = 0.7031

0

100,000

200,000

300,000

400,000

500,000

0 2,000,000 4,000,000 6,000,000

ADF Factor (SOFP Days x Average Annual Departures)

PG/EG 

Gallons 

Per Year

Figure 10-2. ADF Factor vs. PG/EG Gallons for Alaskan Airports 

 EPA used the line equations to estimate the total gallons of ADF used at airports that did 

not have available ADF data in the airport or airline detailed questionnaires. Based on the 

estimated total gallons of ADF used at an airport, EPA calculated the distribution of different 

types of ADF (PG/EG, Type I/Type IV) based on the average percent distribution of the reported 

ADF amounts. See the Airport Deicing Loadings Calculations memorandum (ERG, 2008d) for 

more detail. Table 10-4 presents the final estimates of ADF usage for all airports that received 

the airport questionnaire. 

10.4 Step 2: Calculate the Amount of Pollutant Load Associated with the Applied 

Chemicals

 As deicing chemicals break down in the environment, they increase chemical oxygen 

demand (COD) and biochemical oxygen demand (BOD). EPA calculated the amount of COD 

and BOD (presented as 5 day BOD, or BOD5) associated with the degradation of the applied 

deicing/anti-icing chemicals. 

 EPA considered two approaches to estimate the amount of COD and BOD5 associated 

with deicing chemicals. The first approach involved using laboratory empirical COD and BOD5 

data for deicing chemicals. The second approach involved using standard chemical information 

and stoichiometric equations to estimate COD and BOD5 for each chemical. 

 EPA determined it would not be suitable to use empirical data to estimate loadings for 

three main reasons. First, empirical COD and BOD5 data were not readily available for all 

deicing/anti-icing chemicals. Second, the available empirical data were outdated and brandspecific. Finally, chemical formulations vary significantly over time and by brand, so it is 

inappropriate to apply any given set of empirical data to all airports and chemicals. 

July 2009 10-12 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008b). 

Note: Values may not sum to total usage amounts due to rounding. 

July 2009 10-13 

Table 10-4. ADF Annual Usage Estimates for All Airports that Received the Airport 

Questionnaire 

Airport 

ID Airport Name 

PG Type I 

(gallons) 

PG Type IV 

(gallons) 

EG Type I 

(gallons) 

EG Type IV

(gallons) 

1001 Montgomery Regional (Dannelly Field) 166 22 41 3 

1002 Bert Mooney 9,722 1,293 2,400 177 

1003 Ketchikan International 0 0 18,182 0 

1004 Norfolk International 22,084 2,938 5,451 402 

1005 Roberts Field 10,720 1,426 2,646 195 

1006 Chicago O'Hare International 1,213,301 303,325 0 0 

1007 Yeager 35,450 4,715 8,750 646 

1008 Tucson International 1,675 223 413 31 

1009 Cold Bay 43,759 5,821 10,800 797 

1010 Fairbanks International 0 0 83,335 0 

1011 Lambert-St Louis International 74,778 3,251 227,586 19,507 

1012 Ted Stevens Anchorage International 0 0 420,735 0 

1013 Wiley Post-Will Rogers Mem 275 0 2,781 0 

1014 Albuquerque International Sunport 46,107 6,133 11,380 840 

1015 Gulfport-Biloxi International 1,109 148 274 20 

1016 Tri-State/Milton J. Ferguson Field 9,259 1,232 2,285 169 

1017 Austin Straubel International 44,442 5,912 10,969 810 

1018 Piedmont Triad International 49,169 6,540 12,136 896 

1019 Ontario International 25 3 6 0 

1020 Hartsfield - Jackson Atlanta 

International 

259,100 34,465 63,950 4,720 

1021 Buffalo Niagara International 259,289 25,365 0 0 

1022 Fort Wayne International 46,379 4,033 0 0 

1023 Seattle-Tacoma International 112,631 14,982 27,799 2,052 

1024 Indianapolis International 411,461 40,694 0 0 

1025 Tupelo Regional 587 78 145 11 

1026 Dallas/Fort Worth International 71,720 20,015 63,380 11,675 

1027 Craven County Regional 628 84 155 11 

1028 Denver International 907,530 104,314 41,726 0 

1029 La Guardia 363,868 106,735 9,703 4,852 

1030 Williamsport Regional 7,204 958 1,778 131 

1031 Richmond International 42,442 5,646 10,476 773 

1032 Austin-Bergstrom International 17,198 2,288 4,245 313 

1033 Mc Carran International 7,613 1,013 1,879 139 

1034 Metropolitan Oakland International 0 0 0 0 

1035 San Diego International 0 0 0 0 

1036 Baltimore-Washington International 291,261 32,362 0 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-4 (Continued) 

Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008b). 

Note: Values may not sum to total usage amounts due to rounding. 

July 2009 10-14 

Airport 

ID Airport Name 

PG Type I 

(gallons) 

PG Type IV 

(gallons) 

EG Type I 

(gallons) 

EG Type IV

(gallons) 

1037 George Bush Intercontinental 

Airport/Houston 

8,399 1,844 0 0 

1038 Luis Munoz Marin International 0 0 0 0 

1039 Kahului 0 0 0 0 

1040 Louis Armstrong New Orleans 

International 

0 0 0 0 

1041 Glacier Park International 27,578 3,668 6,807 502 

1042 Orlando International 0 0 0 0 

1043 Ralph Wien Memorial 675 0 1,825 0 

1044 Roanoke Regional/Woodrum Field 23,552 3,133 5,813 429 

1045 Norman Y. Mineta San Jose 

International 

0 0 0 0 

1046 Long Island Mac Arthur 31,135 4,141 7,685 567 

1047 Sacramento Mather 1,282 0 0 0 

1048 Redding Municipal 495 66 122 9 

1049 Lanai 0 0 0 0 

1050 Aspen-Pitkin Co/Sardy Field 10,742 1,429 2,651 196 

1051 Barnstable Muni-Boardman/Polando 

Field 

33,008 4,391 8,147 601 

1052 Wilmington International 1,556 207 384 28 

1053 General Edward Lawrence Logan 

International 

816,104 169,192 0 0 

1054 Jackson Hole 24,413 3,247 6,026 445 

1055 Miami International 0 0 0 0 

1056 Santa Maria Pub/Capt G Allan Hancock 

Field 

0 0 0 0 

1057 Will Rogers World 35,409 4,710 8,740 645 

1058 Gerald R. Ford International 84,414 12,760 0 0 

1059 Greater Rochester International 208,534 20,624 0 0 

1060 Williamson County Regional 107 14 26 2 

1061 William P Hobby 10,134 1,348 2,501 185 

1062 Birmingham International 3,578 476 883 65 

1063 Evansville Regional 14,412 1,917 3,557 263 

1064 Falls International 8,137 1,082 2,008 148 

1065 Albany International 116,971 8,804 0 0 

1066 Salt Lake City International 125,519 34,232 296,681 114,108 

1067 Helena Regional 13,147 1,749 3,245 240 

1068 Eppley Airfield 79,386 10,560 19,594 1,446 

1069 Cleveland-Hopkins International 524,089 58,232 0 0 

1070 City of Colorado Springs Municipal 54,230 7,214 13,385 988 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-4 (Continued) 

Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008b). 

Note: Values may not sum to total usage amounts due to rounding. 

July 2009 10-15 

Airport 

ID Airport Name 

PG Type I 

(gallons) 

PG Type IV 

(gallons) 

EG Type I 

(gallons) 

EG Type IV

(gallons) 

1071 Tweed-New Haven 3,523 469 870 64 

1072 Gillette-Campbell County 630 84 155 11 

1073 Honolulu International 0 0 0 0 

1074 South Bend Regional 22,189 7,396 0 0 

1075 Pensacola Regional 592 79 146 11 

1077 Kona International at Keahole 0 0 0 0 

1078 Nashville International 65,479 8,710 16,161 1,193 

1079 Manchester 154,257 23,050 0 0 

1080 Syracuse Hancock International 180,760 5,591 0 0 

1081 Bob Hope 0 0 0 0 

1082 Trenton Mercer 3,858 513 952 70 

1083 Tampa International 0 0 0 0 

1084 Bismarck Municipal 15,018 1,998 3,707 274 

1085 Waterloo Municipal 5,594 744 1,381 102 

1086 Palm Beach International 732 97 181 13 

1087 El Paso International 11,608 1,544 2,865 211 

1088 Outagamie County Regional 41,375 5,504 10,212 754 

1089 John F Kennedy International 459,225 100,806 0 0 

1090 Boise Air Terminal/Gowen Fld 51,086 6,795 12,609 931 

1091 Rochester International 24,717 3,288 6,101 450 

1092 Lewiston-Nez Perce County 17,781 2,365 4,389 324 

1093 Los Angeles International 0 0 0 0 

1094 Boeing Field/King County International 3,688 491 910 67 

1095 Chicago Midway International 258,574 35,260 0 0 

1096 Santa Fe Municipal 793 105 196 14 

1097 Lovell Field 2,968 395 733 54 

1098 Aberdeen Regional 9,997 1,330 2,467 182 

1099 Sacramento International 0 0 0 0 

1100 Toledo Express 29,728 2,322 13,470 929 

1101 Portland International 80,173 10,664 19,788 1,461 

1102 John Wayne Airport-Orange County 0 0 0 0 

1103 Juneau International 0 0 48,014 0 

1104 Nome 457 0 2,590 0 

1105 Spokane International 62,545 5,439 0 0 

1106 Fort Lauderdale/Hollywood 

International 

0 0 0 0 

1107 Pittsburgh International 830,704 113,278 0 0 

1108 Louisville International-Standiford Field 91,849 12,217 22,670 1,673 

1109 Airborne Airpark 319,988 112,428 0 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-4 (Continued) 

Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008b). 

Note: Values may not sum to total usage amounts due to rounding. 

July 2009 10-16 

Airport 

ID Airport Name 

PG Type I 

(gallons) 

PG Type IV 

(gallons) 

EG Type I 

(gallons) 

EG Type IV

(gallons) 

1110 Aniak 476 0 0 0 

1111 Port Columbus International 265,304 23,070 0 0 

1112 Deadhorse 56,478 7,513 13,940 1,029 

1113 Cincinnati/Northern Kentucky 

International 

171,801 35,792 436,660 78,742 

1114 Stewart International 23,086 3,071 5,698 421 

1115 Jacksonville International 716 95 177 13 

1116 Reno/Tahoe International 53,382 7,101 13,176 973 

1117 Cherry Capital 8,643 0 0 2,881 

1118 Bethel 1,959 0 2,938 0 

1119 Rickenbacker International 7,661 1,019 1,891 140 

1120 Rapid City Regional 18,185 2,419 4,488 331 

1121 Theodore Francis Green State 107,383 14,284 26,504 1,956 

1122 Southwest Florida International 680 90 168 12 

1123 James M Cox Dayton International 80,616 9,964 0 0 

1124 Des Moines International 66,913 11,152 2,390 0 

1125 Sarasota/Bradenton International 0 0 0 0 

1126 Minneapolis-St Paul International/WoldChamberlain 1,354,580 101,958 0 0 

1127 Willow Run 7,313 973 1,805 133 

1128 Charlotte/Douglas International 116,293 27,279 0 0 

1129 Bradley International 375,820 51,248 0 0 

1130 San Antonio International 9,119 1,213 2,251 166 

1131 Wilkes-Barre/Scranton International 30,426 4,047 7,510 554 

1132 Chippewa Valley Regional 9,486 1,262 2,341 173 

1133 Phoenix Sky Harbor International 0 0 0 0 

1134 St George Municipal 9,978 1,327 2,463 182 

1135 Lafayette Regional 1,065 142 263 19 

1136 General Mitchell International 137,650 13,765 0 1,529 

1137 Dallas Love Field 26,622 3,541 6,571 485 

1138 Detroit Metropolitan Wayne County 2,001,632 150,660 0 0 

1139 Philadelphia International 862,385 117,598 0 0 

1140 Memphis International 175,273 23,901 0 0 

1141 Ronald Reagan Washington National 177,822 35,125 6,586 0 

1142 Washington Dulles International 828,584 236,738 10,761 0 

1143 San Francisco International 75 10 19 1 

1144 Central Wisconsin 31,203 4,151 7,702 568 

1145 Newark Liberty International 965,829 157,228 0 0 

1146 Northwest Arkansas Regional 22,013 2,928 5,433 401 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-4 (Continued) 

Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008b). 

Note: Values may not sum to total usage amounts due to rounding. 

July 2009 10-17 

Airport 

ID Airport Name 

PG Type I 

(gallons) 

PG Type IV 

(gallons) 

EG Type I 

(gallons) 

EG Type IV

(gallons) 

1147 Raleigh-Durham International 73,281 9,748 18,087 1,335 

1148 Kansas City International 152,794 16,298 34,633 0 

1149 Fort Worth Alliance 1,477 46 0 0 

1150 Greater Rockford 116,016 30,840 0 0 

1151 Kalamazoo/Battle Creek International 18,482 3,520 0 0 

1152 Duluth International 65,442 2,727 0 0 

1153 Akron - Canton Regional 54,221 6,025 0 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-18 

 EPA selected the second approach, calculating loadings based on standard chemical 

information and stoichiometric equations. The advantage of this methodology over using 

empirical data is that it can be used for all deicing chemicals. In addition, this methodology 

allows the calculations and assumptions used to be clearly presented. EPA checked the validity 

of the COD and BOD5 concentrations for propylene glycol and ethylene glycol calculated using 

this methodology against the available empirical data and found a good match. 

10.4.1 Calculate the Total Mass of Each Pollutant 

 First, EPA estimated the total mass of each chemical based on the airline and airport 

questionnaire responses (which specified varying formulations of ADF and deicing products). To 

calculate the total mass of applied chemical, EPA multiplied the reported mass of each chemical 

by the reported concentration of the chemical. Alternatively, if airport personnel reported a 

volume of chemical in the airport or airline detailed questionnaire, EPA multiplied the reported 

volume by the reported concentration and the chemical density. 

10.4.2 Determine the Theoretical Oxygen Demand of Each Chemical 

 Next, EPA determined the theoretical oxygen demand (ThOD) associated with the 

degradation of each of the deicing chemicals. The ThOD estimate was based on the molecular 

formula of the chemical and the stoichiometric equation of the breakdown of the chemical to the 

end products of carbon dioxide and water. Table 10-5 lists the calculated ThOD for each 

chemical. 

Table 10-5. Theoretical Oxygen Demand Calculations for Deicing Chemicals 

Deicing Compound 

Molecular 

Formula Stoichiometric Formula 

ThOD (Moles of O2

per Mole of Deicing

Compound) 

Propylene glycol C3H8O2 C3H8O2 + 4 O2 Æ 3 CO2 + 4 H2O 4.0 

Ethylene glycol C2H6O2 2[C2H6O2] + 5 O2 Æ 4 CO2 + 6 H2O 2.5 

Urea N2H4CO N2H4CO + 4 O2 Æ 2 HNO3 + CO2 + H2O 4.0 

Potassium acetate KC2H3O2 [C2H3O2] ̄ + 1.75 O2 Æ 2 CO2 + 1.5 H2O 1.75 

Sodium acetate NaC2H3O2 [C2H3O2] ̄ + 1.75 O2 Æ 2 CO2 + 1.5 H2O 1.75 

Calcium magnesium acetate C8H12CaMgO8 [C8H12O8]

4

 ̄ + 7 O2 Æ 8 CO2 + 6 H2O 7.0 

Sodium formate NaHCO2 2[HCO2] ̄ + 0.5 O2 Æ 2 CO2 + H2O 0.25 

10.4.3 Determine the COD of Each Chemical 

 EPA next determined the COD loading associated with the chemical’s degradation. EPA 

assumed that the chemical would completely degrade in the environment over time and therefore 

the calculated ThOD load would be equivalent to the COD load. EPA estimated the COD load 

associated with each reported chemical based on the calculated mass of the chemical purchased, 

the molecular weight of the chemical, the ThOD, and the molecular weight of oxygen, using the 

equation below: 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

grams 434

pound

O of moles

O of grams Molecular O Weight chemical of moles

O of moles ThOD

chemical of grams

chemical of moles Molecular Chemical Weight pound

grams 434 (pounds) Load COD (pounds) Chemical

2

2

2

2 ⎟×

⎠

⎞ ⎜

⎝

⎛ ⎟×

⎠

⎞ ⎜

⎝

⎛ ×

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ = × ×

 (10-1) 

10.4.4 Determine the BOD5 of Each Chemical 

 EPA calculated the BOD5 loading based on the estimated COD loading. EPA developed 

an industry-specific relationship between COD and BOD5 using analytical data for untreated 

deicing stormwater from the EPA sampling episodes at Albany International airport, Pittsburgh 

International airport, and Denver International airport. The average COD/BOD5 ratio was 1.67. 

This relationship was used to calculate the BOD5 associated with the degradation of the deicing 

chemical. See the Airport Deicing Loading Calculations memorandum (ERG, 2008d) for more 

information. 

10.5 Step 3: Estimate the Amount of Baseline Pollutant Load that is Discharged 

Directly

 The amount of applied chemical that is discharged directly is airport-specific and 

dependant upon the existing stormwater collection/treatment system present at each airport. 

Typically, ADF is applied at a number of specific locations at the airport, including gates, 

deicing pads, and/or aprons. Pavement deicing chemicals are applied on a larger area and variety 

of locations, including runways, taxiways, aprons, and gates. Based on EPA site visits and 

questionnaire responses, EPA assumed that pavement deicing chemicals could be present in 

almost every airport outfall, whereas ADF is usually present at a smaller number of outfalls that 

drain only aircraft deicing areas. 

10.5.1 Direct Discharge of Pavement Deicers 

 EPA estimated the amount of pavement deicers that are directly discharged. Because 

pavement deicing chemicals are applied at a large variety of areas at an airport, the amount of 

pavement deicers being directly discharged could range from close to 100 percent on pavement 

areas near outfall drains, to nearly 0 percent for chemicals that may fall onto grassy areas and 

infiltrate into the ground during a thaw. Estimating a percentage of direct discharge release of 

pavement deicers at a particular airport is difficult without performing a detailed study of each 

airport. Therefore, EPA assumed 100 percent direct discharge of pavement deicers to represent 

the maximum possible amount of discharge. 

10.5.2 Direct Discharge of ADF 

 EPA estimated the direct discharge amount of ADF by first estimating the amount of 

applied ADF that would be available for discharge. EPA assumed that 80 percent of applied 

Type I ADF falls onto the pavement at the deicing area and is available for discharge; the 

remaining 20 percent is lost to evaporation, wind, or tire tracking, or adheres to the plane and is 

later sheared off during taxiing and takeoff (Switzenbaum, et al., 1999). EPA assumed that 10 

percent of Type IV ADF falls to the pavement in the deicing area and is available for discharge; 

the remaining 90 percent adheres to the plane. The Agency multiplied the total amount of applied 

July 2009 10-19 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-20 

ADF by the appropriate percentage available for discharge to determine the amount of ADF that 

is available for discharge. 

 Next, EPA determined the percentage of available ADF that would be directly discharged 

at each airport, depending on the airport’s current control and treatment systems (ERG, 2008c). 

EPA estimated collection and control percentages of spent ADF for each airport based on 

information provided during EPA site visits and in the airport questionnaire. If the airport did not 

provide an ADF collection and control percentage estimate, EPA personnel reviewed the 

airport’s questionnaire responses and the reported collection and control percentage of similar 

systems to determine an estimate for the airport. Table 10-6 in Section 10.6 presents the 

collection percentages for each airport. 

 The COD load associated with each ADF chemical applied at an airport was reduced by 

EPA’s estimate of the airport’s current collection and control percentage to estimate the amount 

of ADF directly discharged. These estimates represent the baseline amount of ADF discharged to 

the environment. Table 10-6 in Section 10.6 presents EPA’s estimate of the amount of ADF load 

directly discharged by each airport, as measured in pounds of COD. 

10.6 Step 4: Estimate Pollutant Loading Removals for Each EPA 

Collection/Control Scenario

 EPA’s regulatory options require a specific collection and treatment percentage of 

available (spent) ADF. EPA evaluated three control and treatment scenarios as discussed in 

Section 10: 

• 20% Efficiency Scenario: collection and treatment of 20 percent of spent ADF; 

• 40% Efficiency Scenario: collection and treatment of 40 percent of spent ADF; 

and 

• 60% Efficiency Scenario: collection and treatment of 60 percent of spent ADF. 

 EPA estimated the direct discharge COD load of each collection and control scenario 

accounting for the following two components: 

• The COD load associated with the applied ADF, minus any reductions achieved 

by the collection and control practices implemented; and 

• The COD load that would be discharged from anaerobic fluidized bed (AFB) 

biological treatment. 

 EPA estimated the amount of COD load that would be discharged from treatment for 

each airport that had load reductions in a scenario. Using analytical data from its sampling 

episodes, EPA determined that AFB systems remove 97.5 percent of COD. Therefore, EPA 

assumed that 97.5 percent of the COD load going to treatment would be removed and 2.5 percent 

would be discharged. 

 After estimating the loads for each scenario, EPA estimated the loading reductions as 

compared to baseline. Table 10-6 lists the ADF COD baseline loads and reductions for each 

control and treatment scenario evaluated for proposal. 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

1 Ketchikan was sent an airport questionnaire but did not respond. EPA developed an estimate of annualized costs 

for this airport using existing Alaskan airport information. 

2 Falls International was sent an airport questionnaire but did not respond. 

NA – Not applicable; the airport reported no deicing operations in the airport questionnaire. 

NE – No percent capture was estimated; the airport did not respond to the airport questionnaire. 

July 2009 10-21 

Table 10-6. ADF COD Baseline Loads and Loading Reductions for Each Control and 

Treatment Scenario, by Airport 

Airport 

Current 

ADF 

Collection 

Baseline 

COD Load 

(pounds) 

COD Load 

Reduction 

for 20% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 40% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 60% 

Collection 

and Control 

Scenario 

(pounds) 

Montgomery Regional (Dannelly Field) 0 2,359 460 920 1,380 

Bert Mooney 100 0 0 0 0 

Ketchikan International 1 NA 0 0 0 0 

Norfolk International 20 251,092 0 61,204 122,408 

Roberts Field 100 0 0 0 0 

Chicago O'Hare International 40 8,733,878 0 0 2,838,510 

Yeager 40 302,292 0 0 98,245 

Tucson International 20 19,045 0 4,642 9,285 

Cold Bay 0 621,909 121,272 242,545 363,817 

Fairbanks International 60 319,152 0 0 0 

Lambert-St Louis International 60 1,230,807 0 0 0 

Ted Stevens Anchorage International 40 2,416,962 0 0 785,513 

Wiley Post-Will Rogers Mem 0 29,821 5,815 11,630 17,445 

Albuquerque International Sunport 20 524,227 0 127,780 255,561 

Gulfport-Biloxi International 100 0 0 0 0 

Tri-State/Milton J. Ferguson Field 0 131,595 25,661 51,322 76,983 

Austin Straubel International 40 378,973 0 0 123,166 

Piedmont Triad International 0 698,801 136,266 272,532 408,799 

Ontario International 0 356 214 214 214 

Hartsfield - Jackson Atlanta International 60 1,472,952 0 0 0 

Buffalo Niagara International 40 1,832,048 0 0 595,416 

Fort Wayne International 0 545,428 109,086 218,171 327,257 

Seattle-Tacoma International 0 1,600,739 312,144 624,288 936,432 

Indianapolis International 40 2,907,633 0 0 944,981 

Tupelo Regional 0 8,339 1,626 3,252 4,878 

Dallas/Fort Worth International 60 593,712 0 0 0 

Craven County Regional 0 8,928 5,357 5,357 5,357 

Denver International 93 777,648 0 0 0 

La Guardia 0 4,487,109 874,986 1,749,972 2,624,959 

Williamsport Regional 60 40,953 0 0 0 

Richmond International 40 361,921 0 0 117,624 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-6 (Continued) 

1 Ketchikan was sent an airport questionnaire but did not respond. EPA developed an estimate of annualized costs 

for this airport using existing Alaskan airport information. 

2 Falls International was sent an airport questionnaire but did not respond. 

NA – Not applicable; the airport reported no deicing operations in the airport questionnaire. 

NE – No percent capture was estimated; the airport did not respond to the airport questionnaire. 

July 2009 10-22 

Airport 

Current 

ADF 

Collection 

Baseline 

COD Load 

(pounds) 

COD Load 

Reduction 

for 20% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 40% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 60% 

Collection 

and Control 

Scenario 

(pounds) 

Austin-Bergstrom International 40 146,656 0 0 47,663 

Mc Carran International 40 64,919 0 0 21,099 

Metropolitan Oakland International 100 0 0 0 0 

San Diego International 100 0 0 0 0 

Baltimore-Washington International 60 1,374,218 0 0 0 

George Bush Intercontinental 

Airport/Houston 

40 60,235 0 0 20,078 

Luis Munoz Marin International NA 0 0 0 0 

Kahului NA 0 0 0 0 

Louis Armstrong New Orleans 

International 

100 0 0 0 0 

Glacier Park International 0 391,940 76,428 152,857 229,285 

Orlando International NA 0 0 0 0 

Ralph Wien Memorial 0 25,326 4,939 9,877 14,816 

Roanoke Regional/Woodrum Field 0 334,727 65,272 130,544 195,815 

Norman Y. Mineta San Jose International 10 0 0 0 0 

Long Island Mac Arthur 60 176,997 0 0 0 

Sacramento Mather 20 11,932 0 5,966 5,966 

Redding Municipal 0 7,035 1,372 2,744 4,116 

Lanai NA 0 0 0 0 

Aspen-Pitkin Co/Sardy Field 40 91,601 0 0 30,534 

Barnstable Muni-Boardman/Polando 

Field 

0 469,111 91,477 182,953 274,430 

Wilmington International 0 22,118 4,313 8,626 12,939 

General Edward Lawrence Logan 

International 

0 9,740,474 1,899,392 3,798,785 5,698,177 

Jackson Hole 100 0 0 0 0 

Miami International 0 0 0 0 

Santa Maria Pub/Capt G Allan Hancock 

Fld 

100 0 0 0 0 

Will Rogers World 0 503,236 98,131 196,262 294,393 

Gerald R. Ford International 40 600,371 0 0 200,124 

Greater Rochester International 50 1,228,022 0 0 239,464 

Williamson County Regional 100 0 0 0 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-6 (Continued) 

1 Ketchikan was sent an airport questionnaire but did not respond. EPA developed an estimate of annualized costs 

for this airport using existing Alaskan airport information. 

2 Falls International was sent an airport questionnaire but did not respond. 

NA – Not applicable; the airport reported no deicing operations in the airport questionnaire. 

NE – No percent capture was estimated; the airport did not respond to the airport questionnaire. 

July 2009 10-23 

Airport 

Current 

ADF 

Collection 

Baseline 

COD Load 

(pounds) 

COD Load 

Reduction 

for 20% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 40% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 60% 

Collection 

and Control 

Scenario 

(pounds) 

William P Hobby 100 0 0 0 0 

Birmingham International 0 50,847 9,915 19,830 29,745 

Evansville Regional 0 204,825 39,941 79,882 119,823 

Falls International 2 NE 0 0 0 0 

Albany International 92 109,890 0 0 0 

Salt Lake City International 60 1,794,858 0 0 0 

Helena Regional 100 0 0 0 0 

Eppley Airfield 0 1,128,249 220,009 440,017 660,026 

Cleveland-Hopkins International 40 3,709,111 0 0 1,236,370 

City of Colorado Springs Municipal 40 462,436 0 0 150,292 

Tweed-New Haven 0 50,074 9,764 19,529 29,293 

Gillette-Campbell County 100 0 0 0 0 

Honolulu International NA 0 0 0 0 

South Bend Regional 100 0 0 0 0 

Pensacola Regional 100 0 0 0 0 

Kona International at Keahole NA 0 0 0 0 

Nashville International 60 372,242 0 0 0 

Manchester 0 1,828,125 356,484 712,969 1,069,453 

Syracuse Hancock International 60 844,427 0 0 0 

Bob Hope 100 0 0 0 0 

Trenton Mercer 0 54,836 10,693 21,386 32,079 

Tampa International 100 0 0 0 0 

Bismarck Municipal 0 213,443 41,621 83,243 124,864 

Waterloo Municipal 0 79,504 15,503 31,006 46,510 

Palm Beach International 100 0 0 0 0 

El Paso International 100 0 0 0 0 

Outagamie County Regional 0 588,037 114,667 229,335 344,002 

John F Kennedy International 0 5,489,149 1,070,384 2,140,768 3,211,152 

Boise Air Terminal/Gowen Fld 60 290,420 0 0 0 

Rochester International 40 210,773 0 0 68,501 

Lewiston-Nez Perce County 100 0 0 0 0 

Los Angeles International NA 0 0 0 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-6 (Continued) 

1 Ketchikan was sent an airport questionnaire but did not respond. EPA developed an estimate of annualized costs 

for this airport using existing Alaskan airport information. 

2 Falls International was sent an airport questionnaire but did not respond. 

NA – Not applicable; the airport reported no deicing operations in the airport questionnaire. 

NE – No percent capture was estimated; the airport did not respond to the airport questionnaire. 

July 2009 10-24 

Airport 

Current 

ADF 

Collection 

Baseline 

COD Load 

(pounds) 

COD Load 

Reduction 

for 20% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 40% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 60% 

Collection 

and Control 

Scenario 

(pounds) 

Boeing Field/King County International 40 31,446 0 0 10,220 

Chicago Midway International 100 0 0 0 0 

Santa Fe Municipal 100 0 0 0 0 

Lovell Field 0 42,182 25,309 25,309 25,309 

Aberdeen Regional 100 0 0 0 0 

Sacramento International 20 0 0 0 0 

Toledo Express 20 383,445 0 93,465 186,929 

Portland International 20 911,546 0 222,189 444,379 

John Wayne Airport-Orange County 100 0 0 0 0 

Juneau International 0 459,700 89,641 179,283 268,924 

Nome 0 30,113 5,872 11,744 17,616 

Spokane International 100 0 0 0 0 

Fort Lauderdale/Hollywood International NA 0 0 0 0 

Pittsburgh International 60 3,931,605 0 0 0 

Louisville International-Standiford Field 60 522,149 0 0 0 

Airborne Airpark 40 2,331,713 0 0 757,807 

Aniak 0 5,540 1,080 2,161 3,241 

Port Columbus International 0 3,120,055 608,411 1,216,822 1,825,232 

Deadhorse 100 0 0 0 0 

Cincinnati/Northern Kentucky 

International 

87 822,345 0 0 0 

Stewart International 40 196,863 0 0 63,980 

Jacksonville International 100 0 0 0 0 

Reno/Tahoe International 20 606,939 0 147,941 295,883 

Cherry Capital 100 0 0 0 0 

Bethel 0 50,915 9,928 19,857 29,785 

Rickenbacker International 0 108,882 21,232 42,464 63,696 

Rapid City Regional 0 258,448 50,397 100,795 151,192 

Theodore Francis Green State 60 610,460 0 0 0 

Southwest Florida International 100 0 0 0 0 

James M Cox Dayton International 60 380,946 0 0 0 

Des Moines International 40 490,533 0 0 159,423 

Sarasota/Bradenton International NA 0 0 0 0 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

Table 10-6 (Continued) 

1 Ketchikan was sent an airport questionnaire but did not respond. EPA developed an estimate of annualized costs 

for this airport using existing Alaskan airport information. 

2 Falls International was sent an airport questionnaire but did not respond. 

NA – Not applicable; the airport reported no deicing operations in the airport questionnaire. 

NE – No percent capture was estimated; the airport did not respond to the airport questionnaire. 

July 2009 10-25 

Airport 

Current 

ADF 

Collection 

Baseline 

COD Load 

(pounds) 

COD Load 

Reduction 

for 20% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 40% 

Collection 

and Control 

Scenario 

(pounds) 

COD Load 

Reduction 

for 60% 

Collection 

and Control 

Scenario 

(pounds) 

Minneapolis-St Paul International/WoldChamberlain 60 6,362,897 0 0 0 

Willow Run 40 62,356 0 0 20,785 

Charlotte/Douglas International 0 1,392,605 271,558 543,116 814,674 

Bradley International 60 1,778,704 0 0 0 

San Antonio International 0 129,604 25,273 50,545 75,818 

Wilkes-Barre/Scranton International 0 432,418 84,322 168,643 252,965 

Chippewa Valley Regional 100 0 0 0 0 

Phoenix Sky Harbor International 20 0 0 0 0 

St George Municipal 100 0 0 0 0 

Lafayette Regional 0 15,133 9,080 9,080 9,080 

General Mitchell International 41 957,716 0 0 308,417 

Dallas Love Field 40 227,012 0 0 73,779 

Detroit Metropolitan Wayne County 100 0 0 0 0 

Philadelphia International 85 1,530,580 0 0 0 

Memphis International 0 2,073,854 404,401 808,803 1,213,204 

Ronald Reagan Washington National 40 1,309,731 0 0 436,577 

Washington Dulles International 40 6,052,151 0 0 1,966,949 

San Francisco International 100 0 0 0 0 

Central Wisconsin 0 443,467 86,476 172,952 259,428

Newark Liberty Intl 0 11,464,956 2,235,666 4,471,333 6,706,999

Northwest Arkansas Regional 0 312,852 61,006 122,012 183,018

Raleigh-Durham Intl 0 1,041,489 203,090 406,181 609,271

Kansas City Intl 40 1,279,726 0 0 415,911

Fort Worth Alliance 60 6,898 0 0 0

Greater Rockford 60 557,825 0 0 0

Kalamazoo/Battle Creek Intl 60 88,053 0 0 0

Duluth Intl 0 765,304 149,234 298,468 447,703

Akron - Canton Regional 60 255,826 0 0 0
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-26 

 For each scenario, EPA estimated no load reductions for the airport if the airport collects 

and controls less than the required percentage of spent ADF (e.g., for the 20 percent efficiency 

scenario, if an airport currently collects and controls 20 percent or more of spent ADF, no load 

reductions were estimated for the airport). 

 For airports that used small quantities of ADF, EPA assumed that the airport would 

collect and haul away the ADF contaminated stormwater instead of collecting it for onsite 

treatment. This assumption was made for all scenarios, and EPA assumed that the load 

reductions for these airports would be the same across all scenarios. For more information, 

please refer to the Airport Deicing Loadings Calculations memorandum (ERG, 2008d). 

10.7 Approach for Calculating Urea-Related Reductions

 For this proposal, EPA evaluated the impact of restricting urea as an airfield deicing 

chemical and replacing its use with potassium acetate. Both urea and potassium acetate produce 

COD as they degrade; however, the COD effect from potassium acetate use is significantly less. 

Discontinuing the use of urea as an airfield deicing chemical will also help to eliminate receiving 

water toxicity impacts including ammonia formation as urea breaks down in water and a 

potential contribution to nutrient enrichment. 

 As described above, EPA calculated the COD load associated with urea use at the 

surveyed airports. EPA then evaluated the amount of potassium acetate that would be required to 

replace the current average urea use using a comparison of application rates under varying winter 

conditions (see EPA’s Urea/Potassium Acetate memorandum (ERG, 2008b) for the details of 

this analysis). Based on the COD load associated with the equivalent potassium acetate use, EPA 

determined the potential reductions in COD load. Table 10-7 presents the baseline COD load 

associated with urea, the estimated equivalent COD load if industry converted from urea to 

potassium acetate, and the load reduction. 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-27 

Table 10-7. Baseline COD Load and Potential Load Reduction Associated with the 

Discontinued Use of Urea as an Airfield Deicing Chemical 

Airport ID Airport 

Urea Load 

(lbs of COD) 

Equivalent Potassium 

Acetate Load 

(lbs of COD) 

Potential Load 

Reduction 

(lbs of COD) 

1007 Yeager 56,797 15,663 41,133 

1010 Fairbanks International 816,961 225,297 591,664 

1012 Ted Stevens Anchorage 

International 

3,560,670 981,943 2,578,727 

1013 Wiley Post-Will Rogers Mem 42,624 11,755 30,869 

1016 Tri - State/Milton J Ferguson Field 133,555 36,831 96,724 

1017 Austin Straubel International 88,530 24,414 64,116 

1018 Piedmont Triad International 210,279 57,990 152,289 

1022 Fort Wayne International 571,082 157,490 413,592 

1041 Glacier Park International 710 196 514 

1043 Ralph Wien Memorial 21,312 5,877 15,435 

1053 General Edward Lawrence Logan 

International 

12,148 3,350 8,798 

1066 Salt Lake City International 3,127,198 862,402 2,264,796 

1074 South Bend Regional 69,136 19,066 50,070 

1079 Manchester 47,952 13,224 34,728 

1090 Boise Air Terminal/Gowen Field 864,579 238,429 626,150 

1103 Juneau International 1,082,651 298,568 784,083 

1105 Spokane International 1,361,128 375,365 985,763 

1110 Aniak 5,115 1,411 3,704 

1112 Deadhorse 42,624 11,755 30,869 

1114 Stewart International 323,516 89,218 234,299 

1116 Reno/Tahoe International 15,426 4,254 11,172 

1118 Bethel 140,659 38,790 101,869 

1128 Charlotte/Douglas International 496,464 136,912 359,551 

1129 Bradley International 35,692 9,843 25,849 

1141 Ronald Reagan Washington 

National 

133,555 36,831 96,724 

1144 Central Wisconsin 179,859 49,601 130,259 

1146 Northwest Arkansas Regional 57,542 15,869 41,674 

1147 Raleigh - Durham International 190,387 52,504 137,883 

1150 Greater Rockford 1,396,079 385,004 1,011,076 

1153 Akron - Canton Regional 45,466 12,538 32,927 
Technical Development Document for Proposed Effluent 10. Pollutant Loadings and 

Limitation Guidelines and Standards for the Airport Deicing Category Pollutant Load Reduction Estimates 

July 2009 10-28 

10.8 References 

Switzenbaum, et al. 1999. Workshop: Best Practices for Airport Deicing Stormwater. DCN 

AD00893. 

ERG. 2008a. Memorandum from Steve Strackbein (ERG) to Brian D’Amico and Eric Strassler 

(EPA): The Development of Snow and Freezing Precipitation (SOFP) Days and the Aircraft 

Deicing and Anti-icing Fluid (ADAF) Factor. (January 16). DCN AD00856. 

ERG. 2008b. Memorandum from Steve Strackbein and Mary Willett (ERG) to Brian D’Amico 

and Eric Strassler (EPA): Cost Comparison of Potassium Acetate and Urea Airfield Deicers.

(March 17). DCN AD00843. 

ERG. 2008c. Memorandum from Juliana Stroup and Mary Willett (ERG) to Brian D’Amico 

(EPA): ADF Capture and Control Efficiency Review. (July 7). DCN AD00854. 

ERG. 2008d. Memorandum from Cortney Itle (ERG) to Brian D’Amico (EPA) : Airport Deicing 

Loadings Calculations. (April 17). DCN AD001140. 

USEPA, 2008a. Airport Deicing Loadings Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD00857. 

EPA. 2008b. Airport Deicing Operations ADF Usage Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD001141. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-1 

11. TECHNOLOGY COSTS 

 This section presents EPA’s estimates of costs for the Airport Deicing Category to 

implement the collection and treatment technologies described in Section 9. EPA estimated the 

compliance costs for each collection and treatment scenario to determine potential economic 

impacts on the industry. EPA also weighed these costs against the pollutant load reduction 

benefits. This section includes cost estimates for the collection and treatment scenarios that EPA 

evaluated for the proposed regulation including those that EPA ultimately rejected. Also 

included in this section are estimated costs for airports to implement new airfield deicing 

alternatives to replace urea. The Agency is reporting estimates of potential economic impacts 

associated with the total estimated annualized costs of the proposed regulation separately, in the 

Economic Analysis document. 

 Section 11.1 summarizes the annualized costs for each airport to collect and control 

(through treatment) differing amounts of spent ethylene- and propylene-based aircraft deicing 

fluid. 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 collection and treatment 

technology costs, including an overview of the cost model and example 

calculations showing how the model estimates costs and cost annualization; 

• Section 11.4 Airfield deicing costs; and 

• Section 11.5: References used in this section. 

Tables are presented within the text and figures are presented at the end of the subsections. 

11.1 Summary of Costs

 This subsection summarizes EPA’s annualized costs for each airport to collect and treat 

differing amounts of spent aircraft deicing fluid (ADF). EPA estimated annualized costs based 

on the current level of spent ADF collected and controlled at each airport and the additional 

capital costs and annual operating costs needed to achieve the target collection and control 

percentage. For those airports that EPA estimated collect and control spent ADF at levels greater 

than 60 percent, no incremental annualized costs are required. (Section 10.5.2 discusses the 

current collection and control percentages at each airport.) Table 11-1 presents annualized costs 

for each airport included in EPA’s airport questionnaire by the following scenarios: 

• 20% Efficiency Scenario: includes glycol recovery vehicles (GRVs) and 

anaerobic fluidized bed (AFB) treatment; 

• 40% Efficiency Scenario: includes plug and pump with GRVs and AFB 

treatment; and 

• 60% Efficiency Scenario: includes deicing pads with GRVs and AFB treatment. 

 Section 11.3 provides details on the methodology used to estimate annualized costs from 

capital and annual operating costs. Specific cost model outputs containing both capital and 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-2 

annual costs for individual airports are included in the Airport Deicing Category administrative 

record. 

 EPA selected AFB treatment as the best available technology for ADF-contaminated 

stormwater, based on its ability to produce an effluent stream clean enough for direct discharge. 

Other technologies evaluated for the Airport Deicing Category can recover and recycle glycol 

from ADF-contaminated stormwater. However, the residual waste streams from these 

technologies may require additional treatment or must be discharged to a Public Owned 

Treatment Works (POTW). In addition, the anaerobic fluidized bed reactor has the flexibility to 

accept ADF-contaminated stormwater with a wide range of glycol concentrations. The recycle 

and recovery technologies evaluated by EPA typically require higher glycol concentrations in 

their feed streams to become economical to operate (Switzenbaum, 1999). 

 For airports that occasionally deice aircraft primarily to remove frost, installing 

permanent collection and treatment equipment for spent ADF would not be practical. Instead, 

EPA believes these airports would contract out the deicing stormwater collection and removal 

tasks, and their costs would not vary between the 20 percent and 60 percent collection/control 

scenarios. This costing approach affects the following airports listed in Table 11-1: 

• Ontario International, California; 

• Craven County Regional, North Carolina; 

• Sacramento Mather, California; 

• Lovell Field, Tennessee; and 

• Lafayette Regional, Louisiana. 

Specific details regarding the costs for occasional removal of spent ADF by a local contractor is 

included in a memorandum entitled Estimated Annual Costs for Airports with Limited ADF Use

(ERG, 2008a). 

 Annualized costs shown in Table 11-1 do not consider airfield deicing. EPA recognizes 

that airports will incur additional costs to change from urea to potassium acetate airfield deicing; 

however, the Agency decided to not include these costs in the annualized costs for managing 

spent ADF. The Agency has prepared a detailed memorandum entitled Cost Comparison of 

Potassium Acetate and Urea Airfield Deicers (ERG, 2008b), which outlines the possible 

incremental costs to the industry to replace urea. Section 11.4 summarizes the estimated cost for 

airports to change from urea airfield deicing to potassium acetate deicing. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

1 Treatment includes installation and operation of an anaerobic fluidized bed biological treatment system unless 

otherwise specified. 

2

 Ketchikan was sent an airport questionnaire but did not respond. An estimate of annualized costs was developed 

for this airport using existing Alaska airport information. 

3

 Airport uses small amounts of ADF and assumes will contract all operations for ADF removal and disposal. 

4 Cost assumes additional contract hauling of collected ADF contaminated stormwater. 5 International Falls was sent an airport questionnaire but did not respond. 

July 2009 11-3 

Table 11-1. Annualized Costs by Surveyed Airport for Each Collection and Control 

Scenario Evaluated by EPA 1 

Airport 

Current ADF 

Collection 

Annualized Cost 

for 20% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 40% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 60% Collection 

and Control 

Scenario 

(2006 $) 

Montgomery Regional 

(Dannelly Field) 

0 $92,700 $352,800 $97,200 

Bert Mooney 100 $0 $0 $0 

Ketchikan International 2 2 2 2

Norfolk International 20 $0 $1,799,200 $770,300 

Roberts Field 100 $0 $0 $0 

Chicago O'Hare International 40 $0 $0 $16,875,404 

Yeager 40 $0 $0 $1,002,671 

Tucson International 20 $0 $985,300 $75,900 

Cold Bay 0 $354,700 $721,200 $552,700 

Fairbanks International 60 $0 $0 $0 

Lambert-St Louis 

International 

60 $0 $0 $0 

Ted Stevens Anchorage 

International 

40 $0 $0 $4,269,900 

Wiley Post-Will Rogers 

Memorial 

0 $69,300 $65,600 $174,300 

Albuquerque International 20 $0 $5,763,600 $1,374,600 

Gulfport-Biloxi International 100 $0 $0 $0 

Tri-State/Milton J. FEPAuson 

Field 

0 $143,900 $431,800 $208,000 

Austin Straubel International 40 $0 $0 $703,300 

Piedmont Triad International 0 $1,099,600 $7,639,600 $1,126,200 

Ontario International 3 0 $1,100 $1,100 $1,100 

Hartsfield - Jackson Atlanta 

International 

60 $0 $0 $0 

Buffalo Niagara International 40 $0 $0 $2,396,500 

Fort Wayne International 0 $571,000 $2,423,100 $293,600 

Seattle-Tacoma International 60 $0 $0 $0 

Indianapolis International 40 $0 $0 $7,679,900 

Tupelo Regional 0 $83,200 $354,000 $71,100 

Dallas/Fort Worth 

International 

60 $0 $0 $0 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

Table 11-1 (Continued) 

1 Treatment includes installation and operation of an anaerobic fluidized bed biological treatment system unless 

otherwise specified. 

2

 Ketchikan was sent an airport questionnaire but did not respond. An estimate of annualized costs was developed 

for this airport using existing Alaska airport information. 

3

 Airport uses small amounts of ADF and assumes will contract all operations for ADF removal and disposal. 

4 Cost assumes additional contract hauling of collected ADF contaminated stormwater. 5 International Falls was sent an airport questionnaire but did not respond. 

July 2009 11-4 

Airport 

Current ADF 

Collection 

Annualized Cost 

for 20% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 40% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 60% Collection 

and Control 

Scenario 

(2006 $) 

Craven County Regional 3 0 $2,000 $2,000 $2,000 

Denver International 93 $0 $0 $0 

La Guardia 0 $2,881,300 $6,440,400 $6,238,900 

Williamsport Regional 60 $0 $0 $0 

Richmond International 40 $0 $0 $1,063,300 

Austin-Bergstrom 

International 

40 $0 $0 $927,400 

McCarran International 40 $0 $0 $294,200 

Baltimore-Washington 

International 

60 $0 $0 $0 

George Bush Intercontinental 

Airport/Houston 

40 $0 $0 $10,100 

Glacier Park International 0 $483,500 $972,700 $843,500 

Ralph Wien Memorial 0 $266,200 $511,200 $546,800 

Roanoke Regional/Woodrum 

Field 

0 $621,400 $3,680,400 $639,100 

Long Island MacArthur 60 $0 $0 $0 

Sacramento Mather 3 20 $0 $2,200 $2,200 

Redding Municipal 0 $111,200 $646,400 $78,800 

Aspen-Pitkin Co/Sardy 

Field 4

40 $0 $0 $156,800 

Barnstable MuniBoardman/Polando Field 0 $409,600 $1,566,300 $652,200 

Wilmington International 0 $311,200 $2,726,800 $139,000 

General Edward Lawrence 

Logan International 

0 $4,289,000 $7,116,000 $9,544,000 

Jackson Hole 100 $0 $0 $0 

Will Rogers World 0 $521,200 $2,201,600 $856,900 

Gerald R. Ford International 4 40 $0 $0 $546,600 

Greater Rochester 

International 

50 $0 $0 $2,134,500 

Williamson County Regional 100 $0 $0 $0 

William P Hobby 100 $0 $0 $0 

Birmingham International 0 $221,100 $466,700 $355,000 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

Table 11-1 (Continued) 

1 Treatment includes installation and operation of an anaerobic fluidized bed biological treatment system unless 

otherwise specified. 

2

 Ketchikan was sent an airport questionnaire but did not respond. An estimate of annualized costs was developed 

for this airport using existing Alaska airport information. 

3

 Airport uses small amounts of ADF and assumes will contract all operations for ADF removal and disposal. 

4 Cost assumes additional contract hauling of collected ADF contaminated stormwater. 5 International Falls was sent an airport questionnaire but did not respond. 

July 2009 11-5 

Airport 

Current ADF 

Collection 

Annualized Cost 

for 20% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 40% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 60% Collection 

and Control 

Scenario 

(2006 $) 

Evansville Regional 0 $297,500 $1,166,900 $401,200 

Falls International 5 5 5 5

Albany International 92 $0 $0 $0 

Salt Lake City International 60 $0 $0 $0 

Helena Regional 100 $0 $0 $0 

Eppley Airfield 0 $531,600 $1,466,400 $1,176,500 

Cleveland-Hopkins 

International 4

40 $0 $0 $1,838,200 

City of Colorado Springs 

Municipal 

40 $0 $0 $906,700 

Tweed-New Haven 0 $115,200 $395,400 $127,400 

Gillette-Campbell County 100 $0 $0 $0 

South Bend Regional 100 $0 $0 $0 

Pensacola Regional 100 $0 $0 $0 

Nashville International 60 $0 $0 $0 

Manchester 0 $839,900 $1,474,900 $1,757,600 

Syracuse Hancock 

International 

60 $0 $0 $0 

Trenton Mercer 0 $476,300 $3,978,300 $223,100 

Bismarck Municipal 0 $199,600 $760,800 $271,000 

Waterloo Municipal 0 $130,200 $414,000 $155,000 

El Paso International 100 $0 $0 $0 

Outagamie County Regional 0 $461,500 $1,902,000 $643,000 

John F Kennedy International 0 $2,989,500 $9,774,000 $6,029,600 

Boise Air Terminal/Gowen 

Field 

60 $0 $0 $0 

Rochester International 40 $0. $0 $397,100 

Lewiston-Nez Perce County 100 $0 $0 $0 

Boeing Field/King County 

International 

40 $0 $0 $250,900 

Chicago Midway 

International 

100 $0 $0 $0 

Santa Fe Municipal 100 $0 $0 $0 

Lovell Field 3 0 $6,200 $6,200 $6,200 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

Table 11-1 (Continued) 

1 Treatment includes installation and operation of an anaerobic fluidized bed biological treatment system unless 

otherwise specified. 

2

 Ketchikan was sent an airport questionnaire but did not respond. An estimate of annualized costs was developed 

for this airport using existing Alaska airport information. 

3

 Airport uses small amounts of ADF and assumes will contract all operations for ADF removal and disposal. 

4 Cost assumes additional contract hauling of collected ADF contaminated stormwater. 5 International Falls was sent an airport questionnaire but did not respond. 

July 2009 11-6 

Airport 

Current ADF 

Collection 

Annualized Cost 

for 20% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 40% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 60% Collection 

and Control 

Scenario 

(2006 $) 

Aberdeen Regional 100 $0 $0 $0 

Toledo Express 20 $0 $1,314,800 $684,200 

Portland International 20 $0 $2,467,400 $2,229,800 

Juneau International 0 $496,700 $1,896,500 $813,500 

Nome 0 $462,100 $1,786,500 $552,400 

Spokane International 100 $0 $0 $0 

Pittsburgh International 60 $0 $0 $0 

Louisville InternationalStandiford Field 60 $0 $0 $0 

Airborne Airpark 40 $0 $0 $4,478,100 

Aniak 0 $334,200 $1,123,500 $412,700 

Port Columbus International 0 $1,407,400 $3,772,600 $2,873,300 

Deadhorse 100 $0 $0 $0 

Cincinnati/Northern 

Kentucky International 

87 $0 $0 $0 

Stewart International 40 $0 $0 $0 

Jacksonville International 100 $0 $0 $0 

Reno/Tahoe International 20 $0 $1,054,800 $1,047,400 

Cherry Capital 100 $0 $0 $0 

Bethel 0 $589,200 $1,875,100 $1,079,900 

Rickenbacker International 0 $197,100 $1,018,000 $196,500 

Rapid City Regional 0 $462,400 $2,925,300 $412,500 

Theodore Francis Green State 60 $0 $0 $0 

James M Cox Dayton 

International 

60 $0 $0 $0 

Des Moines International 40 $0 $0 $928,300 

Minneapolis-St Paul 

International/WoldChamberlain 

60 $0 $0 $0 

Willow Run 4 40 $0 $0 $123,900 

Charlotte/Douglas 

International 

0 $1,664,000 $2,241,900 $4,312,700 

Bradley International 60 $0 $0 $0 

San Antonio International 0 $692,700 $4,692,700 $638,900 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

Table 11-1 (Continued) 

1 Treatment includes installation and operation of an anaerobic fluidized bed biological treatment system unless 

otherwise specified. 

2

 Ketchikan was sent an airport questionnaire but did not respond. An estimate of annualized costs was developed 

for this airport using existing Alaska airport information. 

3

 Airport uses small amounts of ADF and assumes will contract all operations for ADF removal and disposal. 

4 Cost assumes additional contract hauling of collected ADF contaminated stormwater. 5 International Falls was sent an airport questionnaire but did not respond. 

July 2009 11-7 

Airport 

Current ADF 

Collection 

Annualized Cost 

for 20% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 40% Collection 

and Control 

Scenario 

(2006 $) 

Annualized Cost 

for 60% Collection 

and Control 

Scenario 

(2006 $) 

Wilkes-Barre/Scranton 

International 

0 $361,300 $1,012,200 $574,400 

Chippewa Valley Regional 100 $0 $0 $0 

St George Municipal 100 $0 $0 $0 

Lafayette Regional 3 0 $2,400 $2,400 $2,400 

General Mitchell 

International 4

41 $0 $0 $1,706,300 

Dallas Love Field 40 $0 $0 $912,000 

Detroit Metropolitan Wayne 

County 

100 $0 $0 $0 

Philadelphia International 85 $0 $0 $0 

Memphis International 0 $1,817,200 $3,771,500 $3,769,600 

Ronald Reagan Washington 

National 4

40 $0 $0 $1,987,300 

Washington Dulles 

International 

40 $0 $0 $18,648,600 

San Francisco International 100 $0 $0 $0 

Central Wisconsin 0 $331,400 $961,000 $517,000 

Newark Liberty International 0 $5,295,600 $10,611,400 $11,277,300 

Northwest Arkansas Regional 0 $314,000 $1,167,100 $514,400 

Raleigh-Durham 

International 

0 $1,096,400 $3,963,300 $1,880,300 

Kansas City International 40 $0 $0 $2,661,400 

Fort Worth Alliance 60 $0 $0 $0 

Greater Rockford 60 $0 $0 $0 

Kalamazoo/Battle Creek 

International 

60 $0 $0 $0 

Duluth International 0 $377,700 $1,043,200 $595,700 

Akron - Canton Regional 60 $0 $0 $0 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-8 

 Table 11-1 shows that for some airports annualized GRV related costs under the 20% 

collection/control scenario can meet or exceed the costs estimated under the deicing pad 60% 

collection/control scenario. In addition, there are also cases where the 40% collection/control 

scenario amortized costs meet or exceed the costs estimated under the deicing pad 60% 

collection/control scenario. These occurrences are a function of the airport factors used to scale 

costs by scenario and whether the predominant costs for an airport are annual costs or capital 

costs. In the case of GRVs and plug and pump systems, the model airport costs are scaled based 

on an airport’s number of deicing outfalls. For deicing pad systems, the model airport costs are 

scaled based on an airport’s number of annual departures. Cases where the GRV costs meet or 

exceed the deicing pad costs are predominantly smaller airports with a low number of departures 

and a high number of deicing stormwater outfalls. In these cases, the high number of deicing 

outfalls results in higher GRV costs (compared to the model airports) and lower deicing pad 

costs (compared to the model airports) due to the low number of departures per year. Cases 

where the plug and pump costs meet or exceed the deicing pad costs are predominantly airports 

with a high number of deicing outfalls compared to their departures. In addition, plug and pump 

systems tend to be labor intensive resulting in high annual O&M costs compared to deicing pad 

systems, which have higher capital costs but lower annual O&M costs. 

11.2 Development of Cost Model Inputs 

 This subsection describes the key inputs to EPA’s cost model for the Airport Deicing 

Category: model sites, ADF usage, deicing days per season, annual airport departures, current 

collection and control technologies in place, estimated percentage of ADF in collected 

stormwater and the number of deicing outfalls at each airport, precipitation data, and physical 

features of each airport. Also discussed are the data sources used to determine these parameters 

and 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 Airport Deicing 

Category. A model airport is an operating airport whose regulatory status and unit operation and 

treatment information were used as parameters for the cost model. EPA selected an airport-byairport approach to estimate compliance costs based on a comparison of information from the 

model airports, as opposed to a more generalized approach, to better characterize the current 

collection and control systems in place for spent ADF and to account for current site conditions 

and airport operations. 

 To select model airports on which to base the costs, EPA reviewed information collected 

during site visits and sampling episodes and compared the information to the control objectives 

to determine which airports could be considered models for the remainder of the industry. Using 

industry-supplied cost data collected from the model airports, the Agency was able to predict 

costs for other airports to achieve similar results. 

 An analysis of the design, operation, and applicability of collection and control 

technologies evaluated for proposal was discussed in Section 9. Based on the analysis of 

collection and control technologies, EPA decided costs should be developed for three collection 

technologies and AFB biological treatment since it provides the best achievable treatment for 

ADF-contaminated stormwater. The remainder of this subsection will focus on model airports 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-9 

having the collection technologies listed in Section 11-1 above and AFB treatment for ADFcontaminated stormwater. 

 The Agency made costing assumptions based on information from a limited number of 

model airports having the selected ADF collection and treatment technology in place. Thus, for 

any given airport, the estimated costs may deviate from those that the airport would actually 

incur. However, EPA considers the compliance costs to be accurate when aggregated on an 

industry-wide basis. 

11.2.2 Airport Operations Data 

 The primary source of airport operations data used to calculate collection and treatment 

costs were responses to the Agency’s 2006 airport questionnaire (USEPA, 2006a). EPA entered 

data from all questionnaires into an electronic database that the cost model then accessed to 

determine if any spent ADF collection and treatment technologies were currently being used; the 

operations data needed to estimate costs for additional collection and treatment was also entered 

into the database. Table 11-2 lists the airport operating data accessed by the cost model to 

estimate both capital and annual operating costs for spent ADF collection and treatment. 

 Two additional pieces of airport operating data not requested in the airport questionnaire 

that were required to estimate costs included annual ADF use and the number of aircraft 

departures. EPA collected data on annual ADF usage in its 2006 airline detailed questionnaire 

(USEPA, 2006b) and information on aircraft departures from the Bureau of Transportation 

Statistics, T-100 Segment Database (USDOT, 2006). ADF use, combined with the expected 

percentage efficiency for a specific collection technology, determined both pollutant reductions 

to surface water and pollutant loadings to on-site treatment. EPA used data on the number of 

aircraft departures as a metric to relate model site collection system costs to other airports that 

were not achieving the collection percentage objective. 

11.2.3 Precipitation Data and Site Characteristics 

 Estimating costs to collect and treat ADF-contaminated stormwater requires knowing the 

expected volume of the stormwater. To predict the annual volume of ADF-contaminated 

stormwater generated at an airport, EPA used precipitation data along with airport site 

characteristics and assumed ADF-contaminated stormwater would be collected from areas where 

ADF is applied and possibly from areas where ADF may drip from the aircraft during taxi and 

takeoff. EPA obtained precipitation data from 1976 to 2006 (30 years) from the National Climate 

Data Center (NOAA) for each airport questionnaire respondent and then averaged the data to 

estimate a monthly average. These data were used by the cost model on an airport-specific basis. 

EPA uses these data, combined with the number of deicing months taken from the questionnaire 

responses, to estimate precipitation that may be contaminated by ADF. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-10 

Table 11-2. Airport Questionnaire Data to Estimate Spent ADF Collection and Treatment 

Costs 

Airport Questionnaire 

Number Description of Question Cost Model Application 

Q3 Location of airport Determine geographical location for the 

airport 

Q7 Use of aircraft deicing chemicals Determine if airport should be included in 

collection and treatment cost estimates 

Q10 Discharge of deicing stormwater to surface 

water 

Determine if on-site treatment may be 

required 

Q11b Number of deicing stormwater outfalls Estimate the cost for annual monitoring 

Q11f SWPPP Information Estimate cost to either create/update 

existing SWPPP with monitoring data 

Q20 Number of deicing days per year Estimate the collection system operating 

time 

Q21 Months deicing is typically performed Estimate the treatment system operating 

period 

Q25 Location where aircraft deicing is 

performed at the airport 

Estimate collection area for ADFcontaminated stormwater 

Q33 Current collection and containment 

methods for deicing stormwater 

Determine technology in place and 

estimate current collection percentage 

Q35 Segregation of high and low concentration 

stormwater and percentage of glycol in 

collected stormwater 

Determine concentration and volume of 

collected stormwater that may require onsite treatment 

Q36 Destination or disposal method for 

collected stormwater 

Determine volume of stormwater that may 

require further on-site treatment 

Q37 On-site or off-site glycol recovery Determine volume of stormwater that may 

require further on-site treatment 

Q43 – Q48 Types of on-site treatment for collected 

stormwater 

Determine if treatment technology is in 

place at airport 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-11 

 EPA estimated the airport site characteristics, including paved and grass areas where 

ADF may have dripped from aircraft during taxi or takeoff, based on a relationship to total 

airport runway area (FAA). The method used to estimate paved and grass areas relative to total 

airport runway area is described in a memorandum entitled Methodology to Estimate ADF 

Contaminated Stormwater Flows (DCN AD00908), which can be found in the Airport Deicing 

Category administrative record. Combining the monthly precipitation data with the paved and 

grass area data allows the cost model to estimate total volume of ADF impacted stormwater that 

may require collection and treatment and to predict the capital and annual cost for the collection 

and treatment equipment. 

11.3 General Methodology for Estimating Collection and Treatment Technology 

Costs

 This subsection describes the methodology for estimating costs, including the 

components of cost, development of cost equations that use airport-specific model inputs to 

estimate capital and annual operating costs, the cost model, and any assumptions made to 

develop costs. 

11.3.1 Overview of the ADF Collection and Treatment Cost Model 

 Managing ADF-contaminated stormwater is a multi-step process. EPA developed a cost 

model to estimate deicing stormwater control costs for each of these steps and the various 

alternatives within each step. Costs for each selected alternative are combined for each airport 

included in the costing effort to develop cost estimates for the different EPA collection and 

control scenarios. For example, regulatory costs at an airport may include a combination of 

alternatives from the collection, containment and storage, and treatment categories. 

 The proposed EPA regulatory requirements may require an airport to collect and control 

deicing stormwater through a variety of mechanisms. As discussed in Section 10, based on 

information provided in the airport questionnaire and data gathered during EPA’s engineering 

site visits to various airports, EPA decided to estimate costs for three collection options. Those 

collection technologies include GRVs alone, a combination of GRVs and a plug and pump 

system in the existing stormwater drainage system, and centralized deicing pads in combination 

with GRVs. Each collection alternatives is expected to provide a different level of collection 

efficiency for ADF-contaminated stormwater. Using only GRVs to mop up ADF-contaminated 

stormwater from areas within the airport where aircraft are deiced is expected to collect only 20 

percent of the applied ADF. Adding a plug and pump system to the existing stormwater drainage 

system to collect contaminated stormwater before it leaves the airport in combination with GRVs 

is expected to collect up to 40 percent of the applied ADF. Changing from gate and apron 

deicing to centralized deicing pads along with GRVs is expected to increase collection to more 

than 60 percent of the applied ADF. Sections 9 and 10 provide detailed information on each of 

these collection alternatives. 

 Once ADF-contaminated stormwater has been collected, the airport has a variety of 

alternatives for control, ranging from disposal at a POTW, to off-site recycle and recovery, onsite recycle and recovery, or on-site treatment and disposal. Again, using information gathered 

from the airport questionnaire and EPA’s engineering site visits, EPA designed the cost model to 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-12 

estimate costs for airports using one of the following alternatives to manage ADF-contaminated 

stormwater: 

• Discharge to a POTW through existing municipal sewers; 

• Contract haul to a POTW; 

• Contract haul to an off-site glycol recovery and recycling facility; 

• Treat on site at a glycol recovery and recycling facility using either ultrafiltration 

and reverse osmosis or mechanical vapor recompression and distillation; or 

• Treat on site to meet specific criteria and discharge to surface water using either 

an AFB treatment system or aerated ponds and lagoons. 

 For any of the above selections, the airport may need on-site containment or storage for 

the collected deicing stormwater before it reaches its final destination. In these cases, 

containment and storage selections can include ponds, underground storage tanks, above-ground 

storage tanks, or temporary storage tanks (e.g., frac tanks). EPA decided to estimate costs for 

each storage option and, based on each airport’s physical features such as available space, select 

the best storage alternative. The collection and control scenarios, for which EPA estimated costs 

did not include on-site treatment through a recovery and recycling facility or aerated ponds and 

lagoons for costing. As discussed previously, however, these technologies may be viable 

alternatives to AFB treatment at specific airports. 

 Airports that currently do not have any collection and containment for ADFcontaminated stormwater may also need to determine their best alternatives to achieve EPA’s 

proposed rule. For these cases, airports may need to conduct an extensive monitoring program at 

each of their outfalls to determine how ADF-contaminated stormwater is leaving the airport and 

to develop design parameters for a new collection and containment system. For large airports 

with many outfalls, the costs to conduct a continual wet-weather monitoring program during the 

deicing season can be extensive. In addition, airports that elect to install on-site treatment and 

discharge to surface waters will be faced with monthly monitoring requirements to verify 

performance. Therefore, EPA decided to include costs for airports to conduct an initial 

monitoring program as well as monthly COD effluent monitoring from on-site treatment 

systems. 

 The airport deicing cost model considers each of these alternatives to develop a costing 

scheme for collecting and containing ADF-contaminated stormwater at each airport. The cost 

model also takes into account the effectiveness of each airport’s current collection and control 

program for ADF-contaminated stormwater to determine what incremental costs should be 

applied to improve collection efficiency to comply with the proposed rule. 

 In general, EPA’s approach to develop costs for the surveyed airports consists of the 

following steps: 

• Step 1: Develop cost equations for each collection, storage, and treatment 

alternative evaluated for proposal using the model airport data; 

• Step 2: Estimate an airport’s current level of spent ADF collection (i.e., 20 

percent, 40 percent or greater than 60 percent) based on information provided in 

the airport questionnaire; 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-13 

• Step 3: Apply the collection and treatment cost equations to those airports that 

currently collect and manage less than the collection and control scenario 

percentage being evaluated to determine airport-specific capital and annual costs 

for that scenario; and 

• Step 4: Estimate annualized costs by airport for each collection and control 

scenario from the airport-specific capital and annual cost components. 

 The airport-specific component costs are combined as needed based on the regulatory 

option and then scaled up to represent national numbers based on EPA’s weighting factors. A 

description of the weighting factors for the Airport Deicing Category is provided in the 

administrative record (USEPA, 2008a). The subsections below describe each of the steps for 

developing annualized cost estimates by airport. 

11.3.2 Cost Model Equation Development 

 Based on the available data, EPA developed cost equations for each collection, storage, 

and treatment alternative that could be applied to those airports not currently achieving the target 

collection percentage in the proposed rule. In general, the Agency developed cost equations from 

the model airports using empirical data rather than attempting to estimate costs for individual 

components within a particular collection or treatment alternative. EPA believes using empirical 

data is a better way to estimate costs because all installed capital and annual operating costs are 

rolled under a single value, eliminating the concern that specific components may not have been 

included. EPA used the empirical cost data from the model airports and information supplied by 

equipment vendors along with airport-specific information to develop normalized cost equations 

that could then be projected to other airports based on common variables. Section 12.4 provides 

specific examples of how the empirical costs from the model airports were projected to other 

airports based using a common variable. The subsections below describe the development of the 

normalized cost equations for each collection, storage, and treatment alternative for ADFcontaminated stormwater. 

11.3.2.1 Collection and Control Alternatives for Spent ADF 

 To select appropriate collection and control technologies, airports must first evaluate the 

amount of ADF-contaminated stormwater leaving the site through a monitoring or surveillance 

program. The monitoring program can involve seasonal wet-weather sampling at stormwater 

outfalls suspected of ADF contamination. To develop costs for an airport-wide sampling and 

monitoring program, EPA estimated labor hours for both sample plan development and sample 

collection, determined vendor costs for equipment to collect samples and measure flows, and 

obtained unit costs from environmental laboratories for sample analysis. Specifics for each of 

these costs are provided in a memorandum entitled Estimated Costs for Initial Monitoring, 

Engineering Assessment and SWPPP Updates for Airports (ERG, 2008c). 

 To establish an estimated monitoring cost for a typical airport, EPA used a surrogate 

airport having five deicing stormwater outfalls and 21 deicing days per year. Estimated annual 

monitoring costs for this airport would be approximately $410,700. Using this cost as a basis, 

EPA developed an equation that the cost model used to estimate annual monitoring costs based 

on the number of deicing outfalls and deicing days per year at other airports. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-14 

 Using the flow and concentration data from the monitoring program, airports will 

perform various engineering assessments to evaluate the percentage of spent deicing fluid that is 

reaching surface water and will develop options to decrease losses to the environment. The 

engineering assessment will likely be conducted by a consulting firm on a time-and-materials 

basis and will prepare a report that can be used to either prepare a new SWPPP or update an 

existing SWPPP with new best management practices (BMPs) for ADF-contaminated 

stormwater. EPA estimated costs for an outside consultant to prepare an engineering assessment 

using the data from the surrogate airport having five deicing outfalls and 21 deicing days per 

year. EPA estimated the cost for this assessment to be $28,400, or $5,680 per stormwater outfall. 

Using the engineering unit cost, the Agency developed an equation that the cost model used to 

estimate costs for an engineering assessment based on the number of deicing stormwater outfalls. 

 Once airports have determined the amount of COD and glycol entering surface waters 

and performed an engineering assessment, they can design a collection and control strategy to 

decrease the amount of ADF leaving the airport through stormwater outfalls. Airports typically 

use one of three collection technologies for ADF-contaminated stormwater: GRVs, plug and 

pump, and deicing pads. The normalized capital and annual costs for each collection and control 

alternative are described below. 

Glycol Recovery Vehicles 

 Airports use GRVs to collect ADF-contaminated stormwater from various locations 

including gate and apron areas, taxi areas and centralized deicing areas. GRVs can be either 

truck-mounted systems or tow-behind units. GRVs are expected to collect approximately 20 

percent of the ADF applied to the aircraft. Because GRVs collect ADF-contaminated stormwater 

from a variety of locations, the glycol concentration in stormwater collected by GRVs is 

expected to range between 0.5 and 10 percent (Switzenbaum, et al., 1999). 

 Using information collected by EPA during the rulemaking development, deicing outfallnormalized GRV costs were developed based on model site data reported in the airport 

questionnaire. EPA assumed that the number of deicing outfalls would be an approximation of 

the size of the deicing area; more deicing outfalls would indicate a larger deicing area and 

increased costs associated with removing ADF from that area. Therefore, EPA related GRV 

capital and annual cost data reported by six model airports to an airport’s reported number of 

deicing outfalls to develop an average capital and annual cost per deicing outfall. Table 11-3 

shows the cost of GRVs reported in the airport questionnaire, the number of outfalls at each 

reporting airport, and the normalized GRV capital cost based on the number of outfalls. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-15 

Table 11-3. Reported Costs for GRVs and Outfall-Normalized Capital and Annual Costs 

Airport 

Number of 

GRVs 

Number of 

Deicing 

Stormwater 

Outfalls 

GRV Capital 

Cost 

(2006 $) 

GRV Annual 

Operating and 

Maintenance 

Cost 

(2006 $/yr) 

GRV 

Normalized 

Capital Cost 

($/outfall) 

GRV 

Normalized 

Annual Cost 

($/yr/outfall) 

1 1 3 $416,000 $16,200 $138,500 $5,400 

2 1 5 $315,000 $82,400 $63,000 $16,500 

3 1 2 $318,000 $5,200 $158,800 $2,600 

4 1 5 $374,000 NA $74,800 NA 

5 1 5 $910,000 $45,800 $91,000 $4,600 

6 1 5 $610,000 NA $121,900 NA 

Averages $108,000 $7,300 

Source: EPA Airport Questionnaire Database, 2006 (USEPA, 2006a). 

NA – Data not available. 

By multiplying the average GRV normalized capital and annual cost factors in Table 11-3 with 

the number of deicing outfalls reported in the airport questionnaire, the cost model could predict 

capital and annual costs for those airports currently not using GRVs to collect at least 20 percent 

of applied ADF. 

Plug and Pump with GRVs 

 The plug and pump collection system with GRVs is applicable to airports that deice at the 

gate rather than at centralized areas. One benefit of deicing at the gate is that it allows the 

components of the existing collection system infrastructure (i.e. existing storm sewers) to be 

incorporated into the plug-and-pump collection system. This can reduce the costs associated with 

designing and constructing a centralized deicing system (e.g., deicing pads). Another benefit of 

at-gate deicing is that airline employees who conduct deicing can conduct other tasks such as 

baggage handling and aircraft departure duties. The primary drawback to at-gate deicing is that a 

much more dilute ADF-contaminated stormwater is collected relative to centralized deicing 

systems, which reduces the feasibility of ADF recycling (Switzenbaum, et al., 1999). 

 The plug and pump collection system utilizes the airport’s existing stormwater collection 

system infrastructure in combination with GRVs to contain and collect ADF-contaminated 

stormwater. The plug-and-pump system operates by placing either temporary inflatable balloons 

or storm sewer shutoff valves in the existing storm sewer system. During deicing events, the 

balloons are inflated and storm sewer shutoff valves are closed, trapping the ADF-contaminated 

stormwater in the collection system. GRVs pump the trapped contaminated stormwater from the 

storm sewer system and transport it to on-site storage while also mopping up ADF-contaminated 

stormwater from the gate, ramp, and apron area surfaces following application. 

 Two airports provided sufficient information to estimate costs for a plug and pump type 

collection system. During the 2005 deicing season, the first airport used sewer balloons at eight 

locations, storm sewer shutoff valves at four locations, and two catch basin inserts. In addition, 

this airport utilized two GRVs; one is a traditional truck-based GRV and the other is a GRV unit 

(a V-Quip Ramp Ranger) that is towed behind a tractor. The estimated capital cost for this 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-16 

airport’s block-and-pump system is approximately $790,000. The plug and pump system 

operated at this airport prevents ADF-contaminated stormwater from discharging through three 

deicing stormwater outfalls (USEPA, 2006c). 

 The second airport, in a small area where ADF-contaminated stormwater is generated, 

uses the plug and pump system to prevent ADF-contaminated stormwater from discharging to 

surface waters. This airport operates 22 block-and-pump locations that prevent ADFcontaminated stormwater from leaving the airport through a maximum of five outfalls. 

According to the airport, the annual budget to operate the plug and pump system is 

approximately $1,300,000. This cost includes permit monitoring, glycol management, the 

pumping contractor, plus other miscellaneous costs (ERG, 2007b). 

 To estimate both capital and annual operating and maintenance (O&M) costs for other 

airports where plug and pump collection may be applicable, EPA normalized the costs based on 

the number of deicing outfalls. EPA assumed that the number of deicing outfalls would reflect 

the size of the deicing area (i.e., more deicing outfalls would indicate a larger deicing area and 

increased costs associated with removing ADF from that area). Table 11-4 presents the 

normalized capital and annual costs for the plug and pump collection system at these airports. 

Table 11-4. Normalized Capital and Operating Costs for the Plug-and-Pump Collection 

System 

Airport 

Deicing 

Outfalls 

Total Capital 

Cost 

(2006 $) 1

Annual O&M Cost 

(2006 $) 

Normalized 

Capital Cost 

($/outfall) 

Normalized Annual 

O&M Cost 

($/outfall) 

Airport 1 3 $790,000 NA $263,400 NA 

Airport 2 5 NA $1,300,000 NA $260,000 

1 Includes both wastewater storage and treatment equipment. 

NA – Data not available. 

Deicing Pads with GRVs 

 Central deicing pads for deicing waste management minimize the volume of deicing 

waste by restricting deicing to confined and controlled areas. Data collected by EPA indicate that 

deicing pads allow airports to collect nearly 68 percent of the ADF (USEPA, 2006e) applied to 

aircraft as compared to block-and-pump collection systems, which can capture up to 42.5 percent 

of the applied ADF (USEPA, 2006c). Central deicing pads are generally constructed of concrete 

with sealed joints to prevent losing glycol through the joints. A number of airports also use 

GRVs in combination with centralized deicing pads to maximize collecting and containing ADFcontaminated stormwater. Pads are typically located near the gate areas or near the ends of the 

runways so that planes can be deiced just prior to takeoff. Deicing at central pads is 

environmentally preferable to deicing at the gate because it minimizes the size of the collection 

area and the amount of wastewater that must be collected. However, central deicing pads are 

sometimes difficult to manage because of scheduling aircraft in and out of the pads during storm 

events. In addition, although the name implies a small collection area, central pads designed to 

accommodate more than one commercial aircraft generally encompass several acres. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-17 

 Three airports have provided information on their costs to install centralized deicing 

pads, show in Table 11-5. To estimate installed capital costs for deicing pads, EPA normalized 

the costs based on the number of aircraft take-offs during the deicing season. EPA decided to use 

the number of aircraft take-offs as the normalizing factor since the number of deicing pads and 

their size is directly related to expected airport ground traffic during the deicing season. The 

normalized capital costs for centralized deicing pads at the three airports, which provided cost 

data is provided in Table 11-5. 

Table 11-5. Normalized Installed Capital Costs for Centralized Deicing Pads 

Airport 

Deicing Season 

Aircraft Take-offs 

Total Installed Capital Cost 

for all Deicing Pads 

(2006 $) 

Normalized Capital Cost 

($/annual takeoffs) 

Airport 1 14,911 $5,100,000 $342 

Airport 2 125,143 $35,000,000 $280 

Airport 3 246,286 $79,300,000 $322 

Average $314.56 

 Deicing pads are expected to require less operation and maintenance than plug-and-pump 

systems. Although deicing pads typically require GRVs to mop up additional ADF-contaminated 

stormwater that does not reach the underground collection system, they require less manual labor 

to install than to install storm sewer plugs and catch basin inserts. In addition, most plug-andpump systems use the existing storm sewer system, so gates and valves typically must be opened 

and closed manually instead of having programmable logic controller (PLC) controlled gates and 

valves that an operator can manage from a remote location. In addition, if the underground 

storage system associated with the deicing pads has sufficient capacity to contain major storm 

events, then temporary tanks typically are not required. According to information EPA obtained 

during the site visit to the General Mitchell International Airport in Milwaukee (USEPA, 2006c), 

the airport rents five temporary tanks to temporarily store spent ADF-contaminated stormwater 

before it is sent to the POTW for anaerobic treatment. According to General Mitchell 

International airport personnel available during the site visit, the total rental cost for temporary 

tanks is approximately $5,000/month. 

 Because no annual O&M cost data for deicing pads were provided in responses to the 

airport questionnaire or available at the time of cost model development, EPA used annual 

block-and-pump cost data, but subtracted the rental cost for temporary storage tanks. According 

to the questionnaire data, the deicing season in the Milwaukee area is approximately five months, 

so total rental of frac tanks during the deicing season is approximately $25,000. The number of 

annual departures in Milwaukee is reported to be 85,128 (USDOT, 2006). Normalizing frac tank 

rental to the number of departures gives $0.29/departure for rental of frac tanks. If O&M costs 

for the block-and-pump system in Milwaukee were normalized to the number of departures, 

costs would be $9.16/depature ($260,000/outfall x 3 outfalls/85,128 departures). Subtracting the 

departure-normalized frac tank costs from the normalized block-and-pump O&M cost gives an 

estimated cost of $8.87/departure ($9.16 - $0.29). 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

11.3.2.2 Off-Site Treatment Alternatives 

 After collecting deicing stormwater, the airport can choose to either treat the stormwater 

or send it away to be treated before its ultimate discharge. Off-site treatment alternatives include 

contract hauling to a POTW for anaerobic treatment, discharging to a POTW for aerobic 

biological treatment, or contract hauling to an off-site glycol recovery/recycling facility. 

Discharge to a POTW 

 Airports have two options for discharging to POTWs: discharge to the POTW through 

municipal sanitary sewers or contract haul to the POTW. From information provided in the 

airport questionnaire, EPA found that 62 airports currently discharge either a portion or all of 

their ADF-contaminated stormwater to a POTW through a municipal sanitary sewer system for 

aerobic treatment. To estimate costs for discharging to the POTW via the sanitary sewer, EPA 

averaged unit-cost data provided by five airports in the airport questionnaire. The average cost 

for aerobic POTW treatment of wastewater from these five airports is $0.01/gallon (USEPA, 

2006a). 

 Since most airports that have can discharge ADF-contaminated stormwater to POTWs 

are likely already doing so, EPA believes these airports will not install new on-site treatment but 

will instead discharge additional stormwater to the POTW to comply with the proposed rule. For 

these airports, EPA developed the following equation to estimate incremental POTW charges. 

POTW lIncrementa Costs

gal

01.0$

glycol %

1 UseADF Capture %Current 

gal

$0.01

glycol %

1 UseADF Capture %Target 

=

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ − × × ×

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛

× × ×

 (11-1) 

 For this equation, the estimated percent glycol in the collected stormwater is expected to 

vary depending on the collection technology used. For example, if GRVs are used to collect 2 

percent of applied ADF, the percent glycol in the collected stormwater is expected to be 

approximately 1.5 percent (1). If plug and pump with GRVs is used to collect ADF-contaminated 

stormwater, the glycol percentage is expected to be 3 percent (Switzenbaum, et al., 1999), and if 

deicing pads are used to collect ADF, the percentage is expected to be approximately 5 percent. 

 Another alternative is contract hauling ADF-contaminated stormwater to a POTW having 

anaerobic digesters. EPA obtained contract hauling and POTW anaerobic treatment costs from 

one airport that contract hauls to a POTW for anaerobic treatment for approximately $0.16 per 

gallon(USEPA, 2006c). EPA believes that, since this airport is currently contract hauling to a 

POTW with anaerobic digestion, it will continue to do so even if it collects additional ADFcontaminated stormwater to comply with the proposed rule. Using the unit-cost data for both 

hauling and treatment, EPA developed an equation to estimate incremental costs for this airport 

to continue contract hauling to a POTW for anaerobic treatment. 

July 2009 11-18 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-19 

Off-Site Glycol Recovery and Recycle 

 Airports within close proximity to a recovery and recycle facility, such as those operated 

by the Environmental Quality Company or Inland Technologies, have an option to contract-haul 

their collected ADF-contaminated stormwater. The airport questionnaire database shows that an 

estimated 13 airports currently ship their collected ADF-contaminated stormwater to an off-site 

facility for glycol recovery. EPA believes airports will continue to contract haul additional ADFcontaminated stormwater to comply with the proposed rule. To estimate incremental costs to 

contract haul additional ADF-contaminated stormwater to an off-site facility for glycol recovery, 

EPA obtained cost data from one airport (USEPA, 2006a). This airport currently collects 40 

percent of its applied ADF and spends $4.88 per gallon on average to contract haul and treat its 

ADF-contaminated stormwater for off-site glycol recovery and recycle. Based on the contracthaul costs from this airport, EPA developed an equation to estimate incremental contract-haul 

and off-site glycol recovery and recycle costs. 

 Of the 13 airports that currently ship their collected ADF-contaminated stormwater 

offsite, EPA estimated that five airports currently collect less than 60 percent of their applied 

glycol for off-site glycol recovery. These five airports will likely continue to contract-haul any 

additional collected ADF to comply with the proposed rule, and therefore the cost model applied 

the incremental off-site glycol recovery costs to only these five airports. 

11.3.2.3 On-Site Treatment Alternatives 

 On-site treatment alternatives evaluated by EPA during the data collection phase of this 

rulemaking included ultrafiltration with reverse osmosis (USEPA, 2006f), mechanical vapor 

recompression (MVR) with distillation (USEPA, 2006g), anaerobic fluid bed biological 

treatment (AFB) (USEPA, 2006h), and aerobic biological treatment ponds (USEPA, 2008b). For 

these on-site treatment alternatives, only the anaerobic fluid bed and aerobic biological treatment 

ponds effectively treated the wastewater for discharge to surface water through a permitted 

outfall. Although ultrafiltration with reverse osmosis and MVR both can recover and potentially 

recycle glycol, neither generated effluents that could be directly discharged to surface water. 

Residual streams from each of these technologies contained significant levels of COD that 

required discharge to a POTW for further processing. The following subsections provide EPA’s 

method for estimating costs for each of these technologies along with the cost equations used by 

the cost model to predict costs for all applicable airports. 

Ultrafiltration with Reverse Osmosis 

 Ultrafiltration with reverse osmosis (UF/RO) treatment is considered a recycle and 

recovery system for spent ADF. The technology generates a concentrated glycol-containing 

stream that can be recycled for possible use in toilets onboard commercial aircraft (i.e., lavatory 

fluid) or recovered and contract hauled off site for resale as a chemical feedstock. The effluent 

from the UF/RO system contains lesser amounts of glycol, cBOD, and COD that is typically 

discharged to a POTW for further processing. The combined UF/RO process will increase the 

glycol concentration in collected ADF-contaminated stormwater to approximately 10 percent 

from its original concentration of between 0.5 and 5 percent depending on the type of collection 

technology used by the airport. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-20 

 Installed capital and O&M costs for a UF/RO treatment system to recycle and recover 

spent ADF-contaminated stormwater were provided by New Logic Research, Inc. (ERG, 2007c). 

According to New Logic, capital costs for a 3 million gal/yr treatment system is approximately 

$962,000 (New Logic Research, 2001). This capital cost does not include storage tanks needed 

for flow equalization prior to treatment; including storage tanks would increase the total installed 

cost to approximately $3.85 million. 

 To estimate both capital and annual O&M costs for airports to install and operate UF/RO 

treatment systems, EPA normalized the costs based on flow (gal/day). Table 10-8 presents the 

flow-normalized installed capital costs for the UF/RO treatment system. The costs in Table 10-8 

assume the effluent from the UF/RO treatment system can be discharged to a POTW for further 

glycol, cBOD, and COD reductions. Costs in Table 11-6 also include costs for storage tanks and 

transfer equipment. The storage tanks provide sufficient equalization to dampen flow and 

concentration changes indicative of deicing events. 

Table 11-6. Flow-Normalized Installed Capital Costs for the UF/RO ADF Treatment 

System 

Location 

Design Flow 

(gal/day) 

Installed Capital Cost 

(2006 $) 1

Design Flow-Normalized 

Capital Cost 

($/gal/day) 

New Logic Research Inc., 

Emeryville, CA 

18,750 $3,850,000 $205.33 

1

 Includes both wastewater storage and treatment equipment. 

 EPA calculated estimated installed capital costs for a UF/RO treatment system using the 

cost model by multiplying the normalized capital cost by the estimated daily flow for each 

airport. Estimated daily flows to treatment were calculated from ADF purchase information for 

each airport, the expected spent ADF collection efficiency for the airport (e.g., 40 percent if plug 

and pump with GRVs are used), the assumed glycol concentration in the collected stormwater, 

and the estimated number of days per year the UF/RO system is operated. For the glycol 

concentration in stormwater, EPA assumed a range of concentrations depending on the type of 

collection method used by the airport to collect spent ADF. Table 11-7 lists the concentration 

ranges, along with the expected ADF percentage collected for each major type of collection 

method. 

Table 11-7. Expected ADF Percentage Collected and ADF Concentration in Collected 

Stormwater 

ADF and Stormwater Collection 

Method 

Expected ADF Percentage 

Collected 

Expected ADF Concentration in 

Stormwater 

GRVs Only 20 1.5 

Plug and pump with GRVs 40 3 

Centralized Deicing Pads with GRVs 60 5 

 EPA selected the range of ADF concentrations in collected stormwater based in 

information provided in the literature. According to one source (19), the minimum concentration 

of glycol in stormwater should range between 3 and 5 percent to be practical for recovery. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-21 

Another source indicated typical values for UF/RO treatment can be approximately 1.5 percent 

(20). Since the concentration of glycol in stormwater will likely increase as more centralized 

locations are used at an airport for deicing, EPA decided to pair the range of concentrations with 

the increasing performance of the collection system. 

 UF/RO treatment systems for ADF-contaminated stormwater will require flow 

equalization tanks prior to treatment to provide a more consistent flow to the system, even 

though aircraft deicing operations may not be occurring. Since operating days per year for the 

UF/RO systems will vary between airports and is based on annual precipitation and the number 

of deicing events per year, EPA decided to arbitrarily select five months of operating time 

(approximately 150 days/yr). Therefore, total annual volumes of collected stormwater are 

divided by 150 days/yr to determine an average daily flow to the UF/RO treatment system. 

 Annual O&M costs for a UF/RO treatment system are calculated using the same 

methodology described above. Table 11-8 shows the flow-normalized costs for operation and 

maintenance of the UF/RO recycle and recovery system. EPA obtained the costs from New 

Logic (20) and escalated them to 2006 costs assuming an inflation rate of 3 percent per year. 

According to New Logic, annual costs to operate a 3 million gallon per year (MGY) treatment 

system are approximately $320,700. For O&M costs, the flow to treatment will be multiplied 

$0.107/gallon. 

Table 11-8. Flow-Normalized Annual O&M Costs for the UF/RO Recycle and Recovery 

System 

Design Flow 

(gal/yr) 

Annual O&M Cost 

(2006 $) 1

Flow-Normalized 

Annual O&M Cost

($/gal) 

New Logic Research Inc., Emeryville, CA 3,000,000 $320,700 $0.107 

1

 Includes both wastewater storage and treatment equipment annual costs. 

MVR with Distillation 

 The MVR and distillation units are considered a recovery and recycle system for spent 

ADF. The system is typically used when glycol concentrations in the stormwater are greater than 

5 percent and present an opportunity to generate a recyclable product that could result in a 

deicing cost credit in some cases. When glycol concentrations are less than 5 percent, recovery 

and recycle of glycol is not practical, and therefore glycol-contaminated stormwater is typically 

discharged directly to the POTW for treatment (Switzenbaum, et al., 1999). The 

MVR/distillation technology generates a concentrated glycol-containing stream (>99 percent) 

that can be sold as a chemical feedstock or possibly be recycled as ADF with additional 

processing. The effluents from the MVR and distillation units contain glycol, cBOD, and COD 

that must be discharged a POTW for further treatment. 

 Two airports provided installed capital and O&M costs for a MVR/distillation system for 

recovery and recycle of propylene glycol from spent ADF-contaminated stormwater (ERG, 

1007d; ERG, 2007e). According to the first airport, installed capital costs for their 10-million 

gallon/season treatment system was approximately $19,421,000. The second airport reported the 

installed capital cost of their system to be $20,315,000 and it treats approximately 3.3 million 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-22 

gallons/season. This cost also includes costs for design, storage tanks, collection piping and 

structures, pumps, electrical and controls, plus the ADF processing equipment. 

 To estimate both installed capital and annual O&M costs for other airports to install and 

operate MVR/distillation to recover and recycle propylene glycol from ADF-contaminated 

stormwater, EPA normalized the costs based on flow (gal/day). Table 11-11 lists the flownormalized installed capital costs for the MVR/distillation recovery and recycle system. The 

costs assume the effluent from the overheads from the MVR/distillation treatment system can be 

discharged to a POTW for further glycol, cBOD, and COD reductions. The costs shown in Table 

11-9 do not include costs to treat the overheads by the POTW. 

Table 11-9. Flow-Normalized Installed Capital Costs for the MVR/Distillation ADF 

Treatment System 

Airport 

Design Flow 

(gal/season) 

Installed Capital Cost 

(2006 $) 1

Flow Normalized Capital 

Cost 

($/gal) 

1 3,265,000 $20,315,000 $6.22 

2 10,000,000 $19,421,000 $1.94 

Average $4.08 

1

 Includes both wastewater storage and treatment equipment. 

To estimate the installed capital cost for a MVR/distillation glycol recovery and recycle 

treatment system, the cost model multiplied by the average flow normalized capital cost in Table 

11-11 by the estimated annual flow for each airport. 

 Annual O&M costs are calculated using the same methodology described above. 

According to Inland Technologies (ERG, 2007f), costs are approximately $0.05/gallon to treat 

ADF-contaminated stormwater using the MVR/distillation system. This cost includes costs for 

electricity for the evaporators, labor, and general maintenance equipment. O&M costs for an 

MVR/distillation recovery and recycle system is calculated by multiplying the annual flow of 

ADF-contaminated stormwater to the MVR system by $0.05/gallon. 

AFB Biological Treatment 

 The AFB biological treatment system uses a vertical, cylindrical tank in which the ADFcontaminated stormwater is pumped upwards through a bed of granular activated carbon at a 

velocity sufficient to fluidize, or suspend, the media. The organic carbon in the ADFcontaminated stormwater is treated by a thin film of microorganisms that grows and coats each 

granular activated carbon particle, providing a vast surface area for biological growth. The 

anaerobic microorganisms occur naturally in sediment, peat bogs, cattle intestines, and even 

brewer's yeast. Breakdown products from the AFB treatment system include methane, carbon 

dioxide, and new biomass. Effluent from the AFB system can be discharged to a local POTW or, 

in most cases, directly to surface water. 

 Treating wastes using an AFB biological treatment system has several advantages over an 

aerobic system. The AFB system requires much less energy since aeration is not required and 

produces significantly less sludge than an aerobic process. In addition, because the biological 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-23 

process is contained in a sealed reactor, odors are eliminated. Methane generated by the AFB can 

be used to heat facility boilers, and if economically feasible, to generate electricity (USDoD, 

2003) creating a potential source of revenue. 

 Two airports have provided installed capital and O&M costs for AFB biological 

treatment systems to treat ADF-contaminated stormwater (ERG, 2007g; ERG, 2007h). Table 11-

10 lists the load and flow-normalized installed capital costs for the both AFB treatment systems. 

The costs shown in Table 11-10 include costs for storage equipment such as tanks and ponds 

prior to anaerobic treatment. The storage equipment provides sufficient equalization to dampen 

flow and concentration changes indicative of deicing events. 

Table 11-10. Load-Normalized Installed Capital Costs for the Anaerobic Fluid Bed 

Reactors 

Airport 

COD Loading 

(lbs/day) 

Installed Capital Cost 

(2006 $) 1

COD Load-Normalized 

Capital Cost 

($/lbs COD/day) 

1 5,200 $8,100,000 $1,558 

2 3,400 $5,990,000 $1,761 

Average $1,659 

1

 Includes both wastewater storage and treatment equipment. 

 Because of the large difference between the design flow-normalized capital costs shown 

in Table 11-10, EPA decided to estimate installed capital costs for AFB treatment systems based 

on COD loading. COD loading is calculated by converting the annual applied ADF (gal/yr) at 

each airport to average daily COD (lbs/day) throughout the entire deicing season and assuming 

an ADF collection efficiency based on the selected collection and control technology. COD 

loading (lbs/day) is then be multiplied by $1,659/lbs COD/day to determine the installed capital 

cost. 

 Annual O&M costs for the AFB biological treatment system are calculated using the 

same methodology described above. Table 11-11 lists the COD loading and flow-normalized 

costs for O&M of the AFB treatment system. For O&M costs, the COD loading to treatment 

(lbs/day) is multiplied by $77.72/yr/lbs/day. 

Table 11-11. Load Normalized Annual O&M Costs for the Anaerobic Fluid Bed Reactors

Airport 

COD Loading 

(lbs/day) 

Annual O&M Cost 

(2006 $) 1

COD Load-Normalized 

Annual O&M Cost 

($/yr/lbs/day) 

1 5,200 $510,000 $98.08 

2 3,400 $195,000 $57.35 

Average $77.72 

1

 Includes both wastewater storage and treatment equipment annual costs. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

Aerobic Biological Treatment Ponds and Piping Costs 

 Airports use retention ponds to equalize both the flow and concentration of aircraft 

deicing fluid (ADF)-contaminated stormwater prior to POTW discharge, or to reduce BOD5

prior to discharging the wastewater to surface water discharge. The actual size of the retention 

ponds depends primarily on expected precipitation and drainage area. The ability to remove 

BOD5 from retention pond effluent depends on oxygen availability for the natural 

microorganisms present in the retention pond. 

 To estimate sizes and costs for ponds at airports, EPA used information provided by a 

large Midwest airport to estimate total pond volume relative to airport runway area. Next, EPA 

used information from an airport in the central United States to develop a unit cost for retention 

ponds (2006 $/gal). For airports that include surface aerators to enhance biological treatment, 

EPA used data provided by a mid-size airport located in the upper Midwest to estimate the 

number and size of surface aerators required for biological treatment. 

 One concern raised by EPA is the space requirements for retention ponds. Unlike other 

technologies, ponds require a large footprint and some airports might not have sufficient space 

for expand and construct a pond (e.g., airports within major cities). To determine if space was 

available for a retention pond system at an airport, EPA examined the total current land use at 

representative airports located in urban areas. Based on the analysis, EPA decided that if an 

airport currently utilizes more then 35 percent of its current area for active airport operations, 

then it was not a candidate for a retention pond system. These airports would need to use aboveground or below-ground tanks to store ADF-contaminated stormwater prior to treatment or offsite discharge to a POTW. 

 EPA previously developed a relationship between gate/apron areas and runway area 

using runway data (FAA) and gate and apron information developed from Google Earth (Google, 

2007), a global mapping system, for specific airports. The relationship of paved gate/apron areas 

to airport runway area is estimated to be 1.8 acres gate/apron per acre of runway. EPA used 

information from the large Midwest airport’s pond storage volume develop the following cost 

equation to estimate retention pond volume based on the airport’s published runway area. 

Retention Estimated (gal) Volume Pond

acreapron and gate

gal 082,169

acrerunway 

acreapron and gate 1.8

acre

ft 43,560 Runway Area,

2

=

× ×

 (11-2) 

 To estimate the cost for the retention pond, EPA used costing data provided by a large 

central U.S. airport. Table 11-12 lists the costs (2006 $) for various ponds that are currently 

being utilized to collect and control ADF at this airport (ERG, 2007e). 

July 2009 11-24 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-25 

Table 11-12. Installed Capital Costs for Various Retention Ponds 

Pond 

Volume 

(gal) 

Installed Capital Cost 

(2006 $) 

Unit Capital Cost 

($/gal) 

1 6,000,000 $4,683,000 $0.78 

2 12,500,000 $2,617,000 $0.21 

3 4,200,000 $4,562,000 $1.09 

4 3,200,000 $1,055,000 $0.33 

5 8,800,000 $2,110,000 $0.24 

Average $0.53 

Using the data from Table 11-12, EPA calculated an average unit capital cost of $0.53 per gallon 

of pond storage. EPA then combined the equation for estimating the retention pond volume with 

this average unit capital cost to develop an equation for estimating installed costs for retention 

ponds at airports when the total runway area is known. 

 To determine annual O&M costs for retention ponds at airports, EPA obtained 

information provided in the airport questionnaire. According to one response to the 

questionnaire, annual costs to provide weed and sediment control at an airport’s three ponds is 

approximately $6,000/yr. The total volume of all three ponds is 20,800,000 gallons. Based on an 

annual cost of $6,000/yr and a total volume of 20,800,000 gallons, the unit O&M costs for 

retention ponds is approximately $0.0003/gallon. EPA combined the pond volume equation 

above with the unit cost for O&M to generate an equation for estimating annual O&M costs for 

retention pond at airports from total runway area. 

 To enhance biological treatment within a retention pond, airports have retrofit ponds with 

surface aerators to increase BOD5 removal. The amount of aeration needed is directly related to 

the amount of ADF used at the airport, since ADF is the primary source of BOD5 in airport 

stormwater. To estimate the number of surface aerators needed for retention ponds based on total 

annual ADF usage, EPA used information provided by the large Midwest airport. EPA 

conducted both a site visit and sampling episode at the airport (USEPA, 2008b). This airport uses 

16 25-horsepower surface aerators in its 16-million gallon treatment pond to remove BOD5 prior 

to direct discharge. The aerators reduce the BOD5 concentration in the retention pond from 

approximately 2,000 mg/l in the winter to less than 30 mg/L when the pond is discharged in late 

spring. According to estimates based on airline detailed questionnaire data, this airport uses 

approximately 146,800 gallons of ADF (both Type I and Type IV) annually. 

 To estimate the cost to place surface aerators in retention ponds at other airports, EPA 

contacted Aqua Aerobics, Inc (ERG, 2007i), a major supplier of surface aerators to the biological 

treatment industry. According to Aqua Aerobics, the book price for a 25-horsepower surface 

aerator is approximately $11,200 and the total installed costs for the aerators can be 

approximated by assuming 1.5 times the purchased equipment cost. Using that estimate, the total 

estimated installed capital cost for all aerators in the retention pond for the Midwest airport is 

approximately $269,000 (2006 $). 

 Based on the airport’s annual ADF estimated usage of 146,800 gallons/year and the total 

estimated installed cost for aerators, EPA estimated the unit cost for surface aerators to be 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-26 

$1.83/gallon ADF used per year. Combining the installed capital cost for aerators with the cost 

for the retention pond, EPA developed an equation that can be used to estimate the installed 

capital cost for retention ponds with surface aerators at airports. 

 To determine annual O&M costs for retention ponds with aerators, EPA accounted for 

the annual cost for weed and sediment control, plus the costs for labor, electrical, materials, 

laboratory analysis, and additional operating chemicals. The large Midwest airport stated in its 

questionnaire that it spends approximately $83,000 per year to operate the aeration pond, with 

electrical cost accounting for nearly 70 percent of the total annual cost. Based on 146,800 gallons 

per year of ADF use, the unit annual cost to operate the aerated retention ponds is approximately 

$0.56/gallon ADF used. 

11.3.2.3 Holding Tanks and Transfer Piping 

 Piping costs to transfer collected stormwater to holding tanks prior to either on-site or 

off-site ADF management will vary for each airport. Variables that could affect transfer piping 

costs include existing subsurface utilities, soil types, elevation changes, and anticipated peak 

precipitation events. Because each of these variables is airport-specific and the details are not 

available, EPA assumed costs would need to be estimated for each airport to construct 1,000 

liner feet of new subsurface stormwater conveyance piping from various areas around the airport. 

EPA believes 1,000 linear feet of piping may be overly conservative at some airports, but less 

than required at others. 

 Elements of a stormwater piping system include subsurface concrete piping, manholes 

and catch basins, a lift station and associated pumps, and knife gates through out the system to 

control the direction of flow. EPA obtained 2002 costs for individual elements within the system 

from RSMeans Heavy Construction Cost Data (RS, 2002) and escalated the costs to 2006 

dollars. The Agency added cost factors for plumbing, electrical, mechanical, and site work to the 

direct costs based on the Department of Defense MILCON estimating procedures (USDoD, 

2001) to obtain total installed direct costs. Indirect costs for engineering, permits, scheduling, 

performance bonds, and contractor markups were added to the total installed direct costs. Table 

11-13 shows the estimated installed capital cost for 1,000 linear feet of a new stormwater 

conveyance piping system at an airport is approximately $502,000. Details regarding capital 

costs plus indirect cost factors are provided in a memorandum entitled Estimated Capital and 

O&M Costs for Collection Ponds and Stormwater Piping (ERG, 2008d) available in the Airport 

Deicing Category administrative record. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-27 

Table 11-13. Estimated Cost for 1,000 Linear Feet of Stormwater Piping 

Description Total Cost 

Trenching for stormwater piping $3,800 

Backfill and compact trench after piping $2,500 

Concrete stormwater piping $13,100 

Manholes/catch basins $11,200 

Manhole frames and covers $3,600 

Knife gates including handwheel operator $7,400 

Pump station to transfer collected stormwater to a holding tank $130,500 

Plumbing (connectors, extra labor, etc.) $56,300 

Mechanical systems (valves) $60,300 

Electrical systems (conduit, motor starters, switches, wiring, etc.) $27,200 

Instrumentation (PLCs, sensors, hardware, software, etc.) $30,500 

Site work (clearing, grading, surveying) $24,100 

Engineering $29,600 

Permits $7,400 

Scheduling $3,000 

Performance bonds $9,300 

Insurance (risk, equipment floater, public liability) $8,500 

Contractor markup (handling, procuring, subcontracting, change orders, etc.) $37,000 

Overhead and profit $37,000 

Total Installed Capital Cost for 1,000’ of Stormwater Piping $502,000 

Source: RSMeans Heavy Construction Cost Data, 2002. (RS, 2002) 

 Annual O&M costs for the piping and conveyance system include labor, electrical and 

spare parts for pumps and gates. To estimate labor costs, EPA assumed one operator would 

monitor the system during each deicing day. The average hourly rate for an operator to monitor 

the system is $32/hr based on data hourly cost data provided in the airport questionnaire. Based 

on a 24-hour event, the labor cost for the stormwater conveyance piping system can be estimated 

from the number of deicing days per year. 

 To estimate electrical costs for the collection system, EPA assumed that one 40-

horsepower pump would operate in the lift station during each storm event and would transfer 

stormwater from the lift station to a retention pond. Based on a typical electrical cost of 

$0.07/kWh, total cost for electricity to operate the transfer pumps can be estimated based on the 

number of deicing days per year. 

 To estimate maintenance equipment costs for the lift station pumps and knife gates, EPA 

used information from Perry’s Chemical Engineers Handbook (Perry, 1984). According to 

Perry’s, annual replacement parts can equal approximately 6 percent of the capital cost for 

equipment. Using the cost data provided in Table 11-13, the annual cost for replacement parts for 

the lift station and knife gate assuming 6 percent replacement would be approximately 

$8,300/year. Combining the labor, electrical, and maintenance equipment costs gives the total 

annual O&M cost for the transfer and piping system. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-28 

Holding Tanks 

 Airports use storage tanks to equalize either flow and/or concentration of ADFcontaminated stormwater prior to POTW discharge or to an on-site treatment system. The actual 

size of the storage tanks depends primarily on the amount of ADF-contaminated stormwater 

generated during precipitation events and the rate at which the wastewater in the tanks can be 

discharged to either the POTW or the on-site treatment system. 

 For airport deicing operations, ERG obtained storage tank volumes from five model 

airports (USEPA, 2006e; ERG, 2007a; McQueen, R., teal.; USEPA, 2006i; USEPA, 2006j). EPA 

also obtained installed capital costs for the storage tanks at three additional model airports (ERG, 

2007d; ERG, 2007e; ERG, 2007h). Using departure data for each of these airports, EPA 

normalized tank volumes and costs to the number of airport departures per year to develop an 

equation that could be used to estimate storage tank sizes and costs at other airports. EPA chose 

airport departures as a normalizing factor since the amount of tank storage needed is directly 

related to the number of aircraft being deiced. In addition, the storage tanks at these airports are 

used to contain ADF-contaminated stormwater prior to discharge to a POTW and/or on-site 

treatment, and therefore the hydraulic capacity has likely been designed with specific discharge 

requirements (e.g., maximum flow and equalized pollutant concentrations). 

 Table 11-14 lists departure information, storage tanks volumes, costs, and normalized 

tank volumes and costs. The data in Table 11-14 indicate the volume of storage tanks at the five 

airports ranges between 0.4 million gallons and 8 million gallons, with the average being 

approximately 2.9 million gallons. The average unit cost for storage tanks calculated from the 

data in Table 11-14 is $1.67/gallon. The departure-normalized storage tank volume, calculated 

from the data provided in Table 10-16, is 24 gallons/departure/year. 

Table 11-14. Storage Tank Volumes and Installed Capital Cost for Various Airports 

Airport 

Number of Airport 

Departures per 

Year 

Total Storage 

Tank Volume

(gal) 

Storage Tank Volume 

per Departure 

(gal/departure/yr) 

Installed 

Capital Cost 

(2006 $) 

Storage Tank 

Capital Cost 

($/gal) 

1 264,051 420,000 2 $795,000 $1.89 

2 14,911 1,500,000 101 $2,890,000 $1.93 

3 96,475 2,000,000 21 NA NA 

4 125,143 2,500,050 20 NA NA 

5 247,165 8,000,000 32 $9,440,000 $1.18 

Average 24 1 $1.67 

1

 Average does not include either Airports 1 or 2. 

NA – Not available. 

Using both the average volume and cost data in Table 11-14, EPA developed an equation to 

estimate costs for storage tanks at all airports based on the number of airport departures per year. 

 Only limited data were available in responses to the airport questionnaire to determine 

the annual O&M cost for storage tanks. One airport reported that annual maintenance costs for 

its storage tanks ranged between $50,000 and $100,000. Using the number of departures per year 

from this airport (41,916/yr) and the average annual O&M cost ($75,000/yr), EPA calculated the 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-29 

normalized annual O&M cost for storage tanks to be $1.79/departure/year. Using the normalized 

cost factor, EPA developed an equation to estimate annual O&M costs for storage tanks at 

airports. 

11.3.3 Cost Model Design 

 This subsection describes how the Airport Deicing Cost Model uses the capital and 

annual cost equations, in combination with the variables included in the model input data, to 

predict costs for each airport. 

11.3.3.1 Airport Deicing Cost Model Description 

 EPA developed the Airport Deicing Cost Model (hereinafter referred to as Cost Model) 

using Microsoft Access and the model uses various tables structured from the airport 

questionnaire data to provide input to the design equations. EPA designed the model to first 

evaluate an airport’s status with the proposed collection efficiency and then build costs based on 

the appropriate types of collection and treatment alternatives needed to achieve the target 

collection efficiency. Figure 11-1 is a diagram showing how the cost model selects and costs the 

various collection alternatives based on input information from the airport questionnaire. 

 The Cost Model uses a series of “Yes – No” statements and the airport’s current 

collection percentage for applied ADF to determine which collection technology costs to apply. 

For example, if EPA estimates an airport is currently collecting 42 percent of its applied ADF, 

the model calculates costs for centralized deicing pads using the appropriate cost equation and 

the input variables for the specific airport. If data from the airport questionnaire indicates an 

airport is currently collecting less than 20 percent of all applied ADF, the cost model estimates 

costs for each collection option: GRVs, plug and pump with GRVs, and centralized deicing pads 

using GRVs. 

 Figure 11-2 shows how the Cost Model selects the appropriate options for the collected 

ADF-contaminated stormwater. As Figure 11-2 indicates, only the AFB treatment system has the 

capability of treating either high or low glycol concentrations in the collected stormwater and 

provides an effluent of sufficient quality for direct discharge. Technologies such as UF/RO and 

MVR/distillation are more economical at higher glycol concentrations (TRB Airport Cooperative 

Research Program, 2009), but still have a residual stream that contains COD concentrations 

above acceptable levels, forcing airports to discharge these residual streams to POTWs for 

further treatment. 

 The Cost Model determines which treatment technologies can be paired with the 

appropriate collection technology. As indicated previously, recycle and recovery technologies 

such as UF/RO and MVR with distillation require higher percentages of glycol in collected 

stormwater to become economical. Therefore, the cost model is designed to provide costs for 

recycle and recovery technologies only when the collection technology will provide the 

appropriate glycol concentration in the collected stormwater. Likewise, technologies such as the 

AFB can operate over a wide range of glycol concentrations and therefore can be applied to all 

types of collection alternatives. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

Does Airport collect more than 

60% of applied ADF?

Is Airport located in a warm 

climate and have small annual 

ADF use?

Does Airport collect more than 

40% but less than 60% of applied 

ADF?

Does Airport collect more than 

20% but less than 40% of applied 

ADF?

Does Airport collect less than 20% 

of applied ADF?

Cost for GRVs, block and pump 

with GRVs and centralized deicing 

pads

No costs

Apply costs for contractor 

recovery and disposal

Cost for centralized deicing 

pads

Cost for centralized deicing 

pads and block and pump 

with GRVs

Yes

Yes

Yes

Yes

Yes

No

No

No

No

Figure 11-1. Diagram Showing the Steps for Developing Collection System Costs by the 

Airport Deicing Cost Model 

July 2009 11-30 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

Aircraft Deicing 

Fluid Application

GRVs Only (20% Capture) 

or 

Block and Pump with GRVs

(40% Capture) 

AFB 

Treatment and 

Direct Discharge

RO/UF 

Glycol Recovery

MVE/Distillation 

Glycol Recovery

Anaerobic

POTW

Off-Site

Recovery

Install Centralized

Deicing Pads

Discharge to

POTW

0.5-3% Glycol 1.5 to 10% Glycol

Aerated

Ponds and Direct 

Discharge

Residual Streams

Figure 11-2. Diagram Showing the Alternatives for Developing Treatment System Costs by 

the Airport Deicing Cost Model 

 The Cost Model provides output costs in Microsoft Excel for each selected collection and 

treatment alternative. The outputs include both installed capital cost and annual operating and 

maintenance costs. Cost model outputs for each airport that is currently not achieving 60 percent 

collection and control of spent ADF are then used to calculate annualized costs by airport. 

Section 11.3.4 provides more detail regarding cost annualization. For those airports, which EPA 

estimates are achieving greater than 60 percent collection and control of applied ADF, the cost 

model output is $0, indicating the airport will require no incremental cost to comply with the 

proposed rule. 

11.3.3.2 Airport Deicing Cost Model Equations 

 As indicated previously, the Cost Model uses capital and annual cost equations in 

combination with various input parameters to estimate costs for collection and treatment 

alternatives at each airport. Table 11-15 describes each cost equation, the equation used by the 

model, the input variable and its source, and any assumptions used by the model to estimate 

costs. 

July 2009 11-31 
11-32 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category July 2009 

Table 11-15. Airport Deicing Cost Model Equations, Input Variables and Assumption

Calculation Description Equation Variables and Sources A

Estimates costs for airports to conduct a one-time monitoring program at each stormwater outfall to determine COD and glycol levels reaching surface water based on current ADF collection and control practices. 

Monitoring Cost ($): Number of Deicing Outfalls × Number Deicing Days/yr × $3,911 

Number of outfalls from the airport questionnaire. Number of deicing days per year for each airport from airport questionnaire. 

Labor costs asswill conduct weoutside consultacosts may be hiCosts assume safor BOD, CODother pollutants be higher. 

Estimates costs for an airport to contract a one-time engineering assessment to determine applicable collection and control technologies. Assessment is based on data collected during the monitoring program. 

Engineering Assessment Cost ($): Number of Outfalls × $5,680/outfall 

Number of outfalls from the airport questionnaire. 

Costs are based of $85/hr. Labor hours for estimates based judgment. 

Estimates the incremental cost for airports to discharge additional ADF-contaminated stormwater to a POTW for aerobic biological treatment. This equation is applicable to those airports that already discharge their ADFcontaminated stormwater to a POTW. 

Incremental POTW Costs ($/yr): (ADF Use × Target % Collect × 1/% glycol × $0.01/gal) - (ADF Use × Current % Collect × 1/% glycol × $0.01/gal) 

ADF use from airline detailed questionnaire Collection % from selected collection technology Glycol percentage from collection technology (1.5% for GRVs only, 3% for plug and pump with GRVs, and 5% for deicing pads) 

The concentratistormwater is eGRVs, 3% from from deicing paAssumes the POadditional ADFstormwater. 

Estimates the incremental cost for airports to contract haul additional ADF-contaminated stormwater to a POTW for anaerobic digestion. This equation is applicable to those airports that currently contract haul to a POTW for anaerobic treatment. 

Incremental POTW Contract Haul Cost ($/yr): (ADF Use × Target % Collect × 1/% glycol × $0.16/gal) - (ADF Use × Current % Collect × 1/% glycol × $0.16/gal) 

ADF use from airline detailed questionnaire Collection % from selected collection technology Glycol percentage from collection technology (1.5% for GRVs only, 3% for plug and pump with GRVs, and 5% for deicing pads) 

The concentratistormwater is eGRVs, 3% from from deicing paAssumes the POadditional ADFstormwater for 
11-33 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 

Table 11-15 (Continued) 

July 2009 

Calculation Description Equation Variables and Sources A

Estimates the incremental cost for airports to contract haul additional ADF-contaminated stormwater to an off-site glycol recovery/recycle facility. This equation is applicable to those airports that currently contract haul to an off-site glycol recovery /recycle facility. 

Incremental Contract Haul and Recycle Cost ($/yr): (ADF Use × Target % Collect × $4.88) - (ADF Use × Current % Collect × $4.88) 

ADF use from airline detailed questionnaire Collection % from selected collection technology 

Assumes airporcontract haul adcontaminated strecovery/recycladditional stormrecovery. 

Estimates costs to purchase and operate GRVs to collect 20% of applied ADF. 

GRV Capital Cost ($) = $108,000 × outfall number GRV Annual Cost($/yr) = $7,300 × outfall number 

Number of stormwater deicing outfalls from the airport questionnaire 

The number of an approximatiodeicing area thaGRVs required

Estimates costs to install and operate a block-and pump collection system with GRVs to collect 40% of applied ADF. 

Plug and pump Capital Cost ($) = $263,400 × outfall number Plug and pump Annual Cost ($/yr) = $260,000 × outfall number 

Number of stormwater deicing outfalls from the airport questionnaire 

The number of an approximatiodeicing area thaGRVs required

Estimates costs to install and operate a deicing pads collection system with GRVs. 

Deicing Pad Capital Cost ($) = $314.56 × departures Deicing Pad Annual Cost ($/yr) = $8.87 × departures 

Annual aircraft departures from Bureau of Transportation Statistics 

The number of size is directly rground traffic d

Estimated cost to install and operate a UF/RO glycol recovery system. 

UF/RO Capital Cost ($) = ADF Use × Collect % × 1/% glycol × 1/150 × $205.33 UF/RO Annual Cost ($/yr) = ADF Use × Collect % × 1/% glycol × $0.107 

ADF use from airline detailed questionnaire Collection % from selected collection technology Glycol percentage from collection technology (3% for plug and pump and 5% for deicing pads) 

The concentratistormwater is eplug and pump pads. The system is e150 days per yeto the airport qu
11-34 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 

Table 11-15 (Continued) 

July 2009 

Calculation Description Equation Variables and Sources A

Estimates cost to install and operate a MVR/distillation glycol recovery system. 

MVR/Distillation Capital Cost ($) = ADF Use × Collect % × 1/ % glycol × $4.08 MVR/Distillation Annual Cost ($/yr) = ADF Use × Collect % × 1/ % glycol × $0.05 

ADF use from airline detailed questionnaire Collection % from selected collection technology Glycol percentage from collection technology (3% for plug and pump and 5% for deicing pads) 

The concentratistormwater is eplug and pump pads1. 

Estimates costs to install an AFB bioreactor treatment system. AFB system costs include a holding tank to equalize both flow and concentration. 

AFB Capital Cost ($) = ADF Use × 14.38 × Collect % × 1/194 × $1,659 AFB Annual Cost ($/yr) = ADF Use × 14.38 × Collect % × 1/194 × $77.72 

ADF use from airline detailed questionnaire Collection % from selected collection technology 

Ultimate COD Type I ADF. Operating periofrom airport qu

Estimated costs to install a nonaerated biological treatment pond. 

Pond volume = Runway Area/43,560 × 1.8 × 169,082 Pond Capital Cost ($) = Pond volume × $0.53 Pond Annual Cost ($/yr) = Pond volume × $0.0003 

Runway area from FAA National Flight Data Center 

Conversion factacres is 43,560. Gate/apron collrunway area (acVolume of pond acre of collectio

Estimates costs to install an aerated biological treatment pond. 

Pond volume = Runway Area/43,560 × 1.8 × 169,082 Aerated Pond Capital Cost ($) = Pond volume × $0.53 + ADF Use × $1.83 Aerated Pond Annual Cost ($/yr) = ADF Use × $0.56/gal 

Runway area from FAA National Flight Data Center ADF use from airline detailed questionnaire 

Conversion factacres is 43,560. Gate/apron collrunway area (acVolume of pond acre of collectio

Estimated costs to install storage tanks to contain collected ADFcontaminated stormwater 

Storage Tank Capital Cost ($) = Departures × 24 × $1.67 Storage Tank Annual Cost ($/yr) = Departures × $1.79 

Annual aircraft departures from Bureau of Transportation Statistics 

Storage tank vogal/departure/yr
11-35 

Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category 

Table 11-15 (Continued) 

July 2009 

Calculation Description Equation Variables and Sources A

Estimated costs to install additional stormwater piping to convey ADF-contaminated water from collection to treatment. 

Piping Capital Cost ($) = $502,000 Piping System Labor Cost ($/yr) = Number deicing days/yr × 24 × $32 Piping System Electrical Cost ($/yr) = 40 × 0.7456 × 24 × Number deicing days/yr × $0.07 Piping System Annual Cost ($/yr) = Labor Cost + Electrical Cost 

None. Deicing days/yr from airport questionnaire. 

Based on 1,000 diameter subsurMotor size for psystem assumed Conversion factis 0.7456. Operators mainhrs per day duriLabor rate of $3questionnaire. Electrical rate oquestionnaire. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-36 

 The equations in Table 11-15 are based on an airport collecting ADF-contaminated 

stormwater from areas within the airport expected to have high concentrations (e.g., greater than 

0.5 percent) glycol. However, EPA also considered the cost impact of collecting stormwater 

from all areas within an airport that could potentially have airfield and ADF contamination. 

Those areas include runways and taxiways, grass areas in and around taxiways and runways, and 

areas at the ends of runways where ADF may be lost from the aircraft during take-off. To 

estimate one-time costs for an “all-flow scenario,” EPA developed equations that would be used 

by the Cost Model to calculate total precipitation volume and estimate collection and treatment 

costs. 

 To estimate the total airport areas where potential airfield and ADF contamination may 

occur, EPA developed a relationship between total airport runway area relative to grass areas, 

apron and gate areas, and taxiway areas. See the memorandum entitled Methodology to Estimate 

the Total Volume of Airport Stormwater Impacted by ADF (DCN AD00914) available in the 

Airport Deicing Category administrative record. Airport runway area is published for all airports 

and therefore this variable could be used to estimate all other areas at airports. First, EPA 

developed a relationship between taxiway length and width to associated runway length and 

width, since aircraft use taxiways to either enter or exit a runway, and taxiways typically parallel 

each runway. EPA’s analysis found that for the six major airports studied, taxiway areas are 

approximately 1.4 times larger than the area of the associated runway. The taxiways’ additional 

area is likely associated with the number of turn-offs and connectors that allow planes to access 

runways at numerous points throughout their entire length. 

 To estimate the airport gate/apron areas covered by concrete relative to the runway area, 

EPA conducted a Google Earth (Google, 2007) analysis of the same six major airports. The 

results showed that, on average, the paved gate/apron areas are approximately 1.8 times larger 

than the total runway area. To estimate the grass areas surrounding gate/apron areas, taxi ways, 

and runways where airfield deicers may be lost and aircraft deicing fluid may fall, EPA 

performed a gross estimation again using Google Earth. Because of the uncertainty of the 

amount of ADF that may drip or drain to grass areas during aircraft movement, EPA decided to 

include all grass areas between taxiways and runways plus a 20-foot grass strip running along 

side each runway. Based on this assumption, EPA estimated that the ratio of grass area to runway 

area is approximately 2. Combining precipitation data for each airport (NOAA) with the areas 

where airfield deicers and ADF may have been lost to either paved or grass areas allowed the 

Cost Model to calculate the total annual volume of all stormwater that may have been 

contaminated. Applying the total volume of potentially contaminated stormwater to the cost 

equations in Table 11-15 calculated industry-wide capital costs approaching 1 trillion dollars and 

annual O&M costs of over 1 billion dollars. Based on this one-time analysis, EPA decided not to 

include collection and treatment of airfield-related stormwater in the proposed regulatory 

options. 

11.3.3.3 Example Cost Calculations 

 The following examples show how the Cost Model used the equations in Table 11-15 

along with the airport questionnaire data to estimate costs for various airports. The examples 

below do not represent actual airports, but are instead designed to show the capabilities of the 

Cost Model. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-37 

Example 1 

 Airport A has six deicing outfalls and currently has no collection or control equipment in 

place for ADF-contaminated stormwater. The airport has 85,000 jet aircraft departures per year 

and uses approximately 490,000 gallons per year of Type 1 and Type IV ADF. The airport has 

23 deicing days per year spanning a five-month period. It does not discharge to a POTW or 

contract haul ADF to an off-site recovery/recycle facility. Target collection of applied ADF is 60 

percent and the airport decides to install and operate an anaerobic fluid bed treatment system. 

One-Time Monitoring and Engineering Cost 

Monitoring Cost = 6 Outfalls × 23 Days/yr × $3,911 = $540,000 

Engineering Cost = 6 Outfalls × $5,680/outfall = $34,000 

Deicing Pad Cost to Achieve 60% Collection Efficiency

Deicing Pad Capital Cost = 85,000 departures/yr × $314.56 = $26.7 million 

Deicing Pad Annual Cost ($/yr) = 85,000 departures/yr × $8.87 = $754,000 

Anaerobic Fluid Bed Biological Treatment System 

AFB Capital Cost ($) = 490,000 gal/yr × 14.38 lbs COD/gal ADF × 0.6 × 1/194 days/yr × $1,659 

= $36.1 million 

AFB Annual Cost ($/yr) = 490,000 gal/yr × 14.38 lb COD/gal ADF × 0.6 × 1/194 × $77.72 

= $1.7 million 

Total Collection and Treatment System Capital Cost: $63.3 million 

Total Collection and Treatment System Annual Cost: $2.4 million/yr 

Example 2 

 Airport B has 3 deicing outfalls and currently uses GRVs to collect approximately 20 

percent of its applied ADF. The concentration of glycol in the collected stormwater is 

approximately 1.5 percent. The airport has conducted a previous monitoring program at each 

outfall and developed a Storm Water Pollution Prevention Plan (SWPPP). The airport has 

117,400 jet aircraft departures per year and uses approximately 417,000 gallons per year of Type 

1 and Type IV ADF. It has 14 deicing days per year spanning a four-month period. The airport 

currently discharges collected deicing stormwater to a POTW. Target collection of applied ADF 

is 60 percent using deicing pads. The expected concentration of glycol in the ADF-contaminated 

stormwater collected from the pads is 5 percent. The airport has decided to install and operate a 

UF/RO system for on-site glycol recovery. Residual effluent from the RO will contain COD that 

will continue to be discharged to the POTW at no additional incremental cost. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-38 

Deicing Pad Cost to Achieve 60% Collection Efficiency

Deicing Pad Capital Cost = 117,400 departures/yr × $314.56 = $36.9 million 

Deicing Pad Annual Cost ($/yr) = 117,400 departures/yr × $8.87 = $1 million/yr 

Collection Tank and Piping for ADF Contaminated Stormwater 

Storage Tank Capital Cost ($) = 117,400 × 24 × $1.67 = $4.7 million 

Storage Tank Annual Cost ($/yr) = 117,400 × $1.79 = $210,000/yr 

Piping and Lift Station Capital Cost ($) = $502,000 

Piping and Lift Station Annual Cost ($/yr) 

Labor Cost ($/yr) = 14 days/yr × 24 × $32 = $10,800/yr 

Electrical Cost ($/yr) = 40 × 0.7456 × 24 × 14 days/yr × $0.07 = $700/yr 

UF/RO Recovery and Recycle Treatment System

UF/RO Capital Cost ($) = 417,000 gal/yr × 0.6 × 1/0.05 × 1/(4×30) × $205.33 = $8.6 million 

UF/RO Annual Cost ($/yr) = 417,000 gal/yr x 0.6 x 1/0.05 x $0.107/gal = $535,000/yr 

Total Collection and Treatment System Capital Cost: $50.7 million 

Total Collection and Treatment System Annual Cost: $1.8 million/yr 

11.3.4 Annualized Costs for ADF Collection and Treatment Alternatives 

 The first step in projecting the economic and financial impacts of proposed effluent 

limitation guidelines and standards (ELGs) on airports is cost annualization. For each airport, 

EPA used the capital and operating and maintenance costs from the Cost Model for each ADF 

target removal percentage over 20 years, discounted future costs using an airport-specific 

opportunity cost of capital, and annualized those costs to represent 20 equal annual cost 

payments incurred by the airport. Because the expected service life of each technology basis 

differs, the capital cost estimates incorporate costs to replace GRVs and block-and-pump 

technologies; for the purposes of projecting capital costs, EPA expects both these technologies 

will require replacement after 10 years, while a deicing pad is expected to last 20 years before 

needing to be replaced. 

 EPA assumed airports will issue tax-exempt, fixed coupon rate serial General Airport 

Revenue Bonds (GARBs) to fund capital expenditures. The Agency also assumed airports will 

issue bonds equivalent to the net present value of capital costs plus 3 percent to account for bond 

issuance costs. The Cost Model annualized capital costs using each airport’s nominal bond rate 

for its most recent GARB issue. This was converted to a real rate using an average annual 

inflation rate of 2.3 percent over the last five years. The average nominal discount rate for costed 

airports was 5.25 percent, which is equivalent to 2.87 percent after accounting for inflation. 

Costs were then annualized over 20 years. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-39 

11.4 Airfield Deicing Costs

 While the proposed regulation requirement is a numeric limit for ammonia, it is 

anticipated that the means of compliance will be product substitution. This subsection includes 

EPA’s cost evaluation for changing from urea to potassium acetate for pavement deicing. 

Information collected by EPA as part of this proposed rulemaking effort indicates that using urea 

as an airfield deicing chemical is being phased out due to concerns with its environmental 

impacts and the availability of less harmful alternatives. Responses to EPA’s airport 

questionnaire indicated that potassium acetate was by far the predominant airfield deicing 

chemical in use from 2002 to 2005, representing about 80 percent of all airfield deicing chemical 

use; however, approximately 35 of the surveyed airports continue to use urea for airfield deicing. 

11.4.1 Urea and Potassium Acetate Chemical Costs and Application Rates 

 To determine cost differences between urea and potassium acetate, EPA utilized data 

from the airport questionnaire. EPA also obtained unit costs for potassium acetate and urea from 

eight airports that use both for airfield deicing. Table 11-16 shows the average costs for urea and 

potassium acetate based on the information provided by the eight airports from 2002 to 2005. 

Table 11-16. Average Cost for Urea and Potassium Acetate, 2002-2005 

Year Average Urea Cost Average Liquid Potassium Acetate Cost

2002 $268.17/ton $2.81/gallon 

2003 $280.57/ton $2.86/gallon 

2004 $297.90/ton $2.86/gallon 

2005 $300.21/ton $2.92/gallon 

Potassium acetate is applied at different rates depending on the weather conditions and the 

thickness of the ice layer at the time of application. Table 11-17 shows the typical deicing, antiicing and prewetting application rates for four commercial potassium acetate runway deicers. 

Table 11-17. Typical Application Rates for Potassium Acetate 

Brand Name Deicing Application Rates 

Anti-Icing 

Application Rates Prewetting Application Rates 

Safeway® KA Runway 

Deicing Fluid 1

1 gal/1000 ft2 0.4gal/1,000 ft2 70% solid and 30% liquid 

Cryotech E-36® LRD 2,3 1 gal/1000 ft2 (thin ice) and 

3 gal/1000 ft2

 (2.5cm thick 

ice) 

0.5 gal/1,000 ft2 85-95% solid and 5-15% liquid, 

or 130g/kg of solid deicer, 

1.25gal/100lbs. solid deicer 

IceClear RDF 4 1 gal/1000 ft2 (thin ice) and 

3 gal/1000 ft2

 (1in. thick ice) 

0.5 gal/1,000 ft2

PEAK® PA 5 1 gal/1000 ft2 0.4 gal/1,000 ft2 70% solid and 30% liquid 

1 http://www.theblackfootcompany.com/new/de-ice/ka.htm. 2 http://www.proviron.com/Deice/E36/e36_tech.html. 3 http://www.p2pays.org/ref/19/18054.htm. 4 http://www.orisonmarketing.com/deicers/RDF1/RDF1.html. 5 http://www.oldworldind.com/chemicals/specs/pk_pa_spec.pdf. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-40 

 Although EPA could not obtain actual application rates for potassium acetate at 

individual airports, EPA did obtain airfield application rates for sodium acetate; therefore, the 

Agency used sodium acetate rates as a surrogate to estimate potassium acetate application rates. 

The amount of sodium acetate required to provide the same protection time as urea is between 66 

and 70 percent (Transport Canada, 1998). Table 11-18 lists typical application rates for Cryotech 

NAAC®, a commercial sodium acetate deicer, as well as the calculated application rates for urea. 

Table 11-18. Application Rates for Sodium Acetate and Urea 

Sodium Acetate, Cryotech NAAC®, Application Rate 1 Calculated Urea Application Rate 

Near 32° F on thin ice = 3 - 5 lbs/1000 ft2 Near 32° F on thin ice = 4.3 - 7.1 lbs/1000 ft2

Less than 10° F on 1 inch ice = 10 - 25 lbs/1000 ft2 Less than 10° F 2 on 1 inch ice = 14.3 - 35.7 lbs/1000 

ft2 

1 http://www.peterschemical.com/sodium-acetate/. 2 Urea loses its effect at temperatures below 20°F. 

Using the information in Table 11-18, EPA estimated the application costs for urea and 

potassium acetate based on the 2005 average unit costs ($/1,000 ft2), as shown in Table 11-19. 

Table 11-19. Cost for Application of Urea and Potassium Acetate, per 1000 Square Feet 

Chemical 

Deicing Application Cost 

(per 1000 ft2) 

Anti-Icing Application Cost 

(per 1000 ft2) 

Urea $0.65 - $1.07, Near 32° F on thin ice 

Potassium Acetate $2.92 (thin ice) and $8.76 (thick ice) $1.17 - $1.46 

11.4.2 Cost Impact of Discontinuing Urea Airfield Deicing 

 The national average use of urea, based on responses to the airport questionnaire for the 

three deicing seasons between 2002 and 2005, was 7,075,865 pounds per year, costing an 

estimated $1,064,998/yr. Using the available range of application rates (small coverage area and 

large coverage area for the same amount of urea) and statistical airport weighting values, EPA 

estimated the chemical costs for all airports currently using urea to change to potassium acetate. 

 Table 11-20 presents the data to determine the additional chemical cost associated with a 

switch to potassium acetate. The estimated increase in cost for these airports to change from urea 

to potassium acetate for airfield deicing is $3.8 million per year (2006 $). The costs in 

Table 11-20 are not weighted to the entire airport industry and do not reflect capital costs for 

new equipment that may be required for airports to change from a solid form of urea application 

to a liquid form of potassium acetate. 

11.4.3 Urea Monitoring Costs 

 Although EPA anticipates that airports subject to the proposed rule will use alternatives 

to urea for pavement deicing, the Agency has developed numerical effluent limitations for 

ammonia as a compliance alternative. Demonstrating compliance with this limitation would 

require total nitrogen monitoring for those airports still using urea for airfield deicing. EPA 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-41 

calculated yearly monitoring costs for the 35 airports that reported urea use during the 2005 

deicing season. The Agency calculated total monitoring costs by combining the costs associated 

with analytical sample testing and sample collection labor costs. In calculating analytical testing 

costs, EPA assumed that every airport would need to test one sample per day, per airport outfall 

that receives deicing stormwater. EPA also assumed that testing would occur five days a week 

for 26 weeks, totaling 130 samples per outfall per year at an approximate cost of $24.00 per 

sample. In calculating labor costs, EPA assumed that each sample collected would take one hour 

to retrieve and process at a cost of $33.00 per hour. Table 11-21 presents the total costs 

associated with monitoring urea at each airport, broken down by analytical testing and labor 

costs for each airport. EPA predicts total annual urea monitoring costs for these airports could 

reach approximately $1.1 million per year (2006 $). 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-42 

Table 11-20. Incremental Costs for Airports to Change from Urea to Potassium Acetate for 

Airfield Deicing 

Airport Name 

Estimated Actual 

Annual Urea Cost 

($/yr 2006) 

Predicted Potassium 

Acetate Cost 

($/yr 2006) 

Incremental Cost to 

Change from Urea to 

Potassium Acetate 

($/yr 2006) 

Yeager $4,000 $18,100 $14,100 

Fairbanks International $57,700 $260,300 $202,600 

Ted Stevens Anchorage International $251,500 $1,134,500 $883,100 

Wiley Post-Will Rogers Mem $3,000 $13,600 $10,600 

Tri - State/Milton J FEPAuson Field $9,400 $42,600 $33,100 

Austin Straubel International $6,300 $28,200 $22,000 

Piedmont Triad International $14,800 $67,000 $52,200 

Fort Wayne International $40,300 $182,000 $141,600 

Glacier Park International $50 $230 $180 

Ralph Wien Memorial $1,500 $6,800 $5,300 

General Edward Lawrence Logan 

International 

$860 $3,900 $3,000 

Salt Lake City International $220,900 $996,400 $775,600 

South Bend Regional $4,900 $22,000 $17,100 

Manchester $3,400 $15,300 $11,900 

Waterloo Municipal $900 $4,100 $3,200 

Boise Air Terminal/Gowen Field $61,100 $275,500 $214,400 

Juneau International $76,500 $345,000 $268,500 

Spokane International $96,100 $433,700 $337,600 

Aniak $400 $1,600 $1,300 

Deadhorse $3,000 $13,600 $10,600 

Stewart International $22,900 $103,100 $80,200 

Reno/Tahoe International $1,100 $4,900 $3,800 

Bethel $9,900 $44,800 $34,900 

Charlotte/Douglas International $35,100 $158,200 $123,100 

Bradley International $2,500 $11,400 $8,900 

Ronald Reagan Washington National $9,400 $42,600 $33,100 

Central Wisconsin $12,700 $57,300 $44,600 

Northwest Arkansas Regional $4,100 $18,300 $14,300 

Raleigh - Durham International $13,400 $60,700 $47,200 

Greater Rockford $98,600 $444,900 $346,200 

Akron - Canton Regional $3,200 $14,500 $11,300 

Total Incremental Cost ($/yr) $3,755,600 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

NA – Airports with “NA” reported urea use but reported no deicing impacted outfalls. 

July 2009 11-43 

Table 11-21. Estimated Annual Costs for Airports to Conduct Effluent Monitoring 

Program For Urea Airfield Deicing 

Airport Name 

Monitoring 

Analytical Costs 

($/yr) 

Monitoring Labor 

Costs 

($/yr) 

Total Urea 

Monitoring Costs 

($/yr) 

Yeager $37,440 $51,480 $88,920 

Fairbanks International $21,840 $30,030 $51,870 

Ted Stevens Anchorage International $15,600 $21,450 $37,050 

Wiley Post-Will Rogers Mem NA NA NA 

Tri - State/Milton J FEPAuson Field $3,120 $4,290 $7,410 

Austin Straubel International $6,240 $8,580 $14,820 

Piedmont Triad International $74,880 $102,960 $177,840 

Fort Wayne International $24,960 $34,320 $59,280 

Glacier Park International $3,120 $4,290 $7,410 

Ralph Wien Memorial $3,120 $4,290 $7,410 

General Edward Lawrence Logan 

International 

$9,360 $12,870 $22,230 

Salt Lake City International $15,600 $21,450 $37,050 

City of Colorado Springs Municipal $3,120 $4,290 $7,410 

South Bend Regional NA NA NA 

Manchester $3,120 $4,290 $7,410 

Waterloo Municipal $3,120 $4,290 $7,410 

Boise Air Terminal/Gowen Field NA NA NA 

Rochester International $9,360 $12,870 $22,230 

Juneau International $15,600 $21,450 $37,050 

Spokane International NA NA NA 

Aniak $9,360 $12,870 $22,230 

Deadhorse NA NA NA 

Stewart International NA NA NA 

Reno/Tahoe International $6,240 $8,580 $14,820 

Bethel $15,600 $21,450 $37,050 

Charlotte/Douglas International $6,240 $8,580 $14,820 

Bradley International $28,080 $38,610 $66,690 

San Antonio International $46,800 $64,350 $111,150 

Wilkes - Barre/Scranton International $6,240 $8,580 $14,820 

Ronald Reagan Washington National $12,480 $17,160 $29,640 

Central Wisconsin $6,240 $8,580 $14,820 

Northwest Arkansas Regional $9,360 $12,870 $22,230 

Raleigh - Durham International $31,200 $42,900 $74,100 

Greater Rockford $3,120 $4,290 $7,410 

Akron - Canton Regional $28,080 $38,610 $66,690 

Total Annual Monitoring Cost ($/yr) $1,089,300
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-44 

11.5 References

ERG. 2008a. Memorandum from Cortney Itle and Robyn Reid (ERG) to Airport Deicing 

Administrative Record: Estimated Annual Costs for Airports with Limited ADF Use. (February). 

DCN AD00913. 

ERG. 2008b. Memorandum from Steve Strackbein and Mary Willett (ERG) to Brian D’Amico 

and Eric Strassler (EPA): Cost Comparison of Potassium Acetate and Urea Airfield Deicers.

(March 17). DCN AD00843. 

ERG. 2008c. Memorandum from Cortney Itle and Robyn Reid (ERG) to Airport Deicing 

Administrative Record: Estimated Costs for Initial Monitoring, Engineering Assessment and 

SWPPP Updates for Airports. (February). DCN AD00910. 

ERG. 2008d. Memorandum from Cortney Itle and Robyn Reid (ERG) to Airport Deicing 

Administrative Record: Estimated Capital and O&M Costs for Collection Ponds and Stormwater 

Piping. (February). DCN AD00912. 

ERG. 2007. Memorandum from Juliana Stroup and Mary Willett (ERG) to Brian D’Amico 

(EPA): Aircraft Deicing Stormwater Control Technologies and Their Removal Efficiencies. 

(December 17). DCN AD00855. 

Switzenbaum, M., et al. 1999. Workshop: Best Management Practices for Airport Deicing 

Stormwater. (July 28). DCN AD00893. 

USEPA. 2006a. Airport Deicing Questionnaire Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD00927. 

USEPA. 2006b. Airline Deicing Questionnaire Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD00938. 

USDOT. 2006. U.S. Department of Transportation, Bureau of Transportation Statistics, T-100 

Segment Database. DCN AD00928. 

NOAA. U.S. Department of Commerce, National Oceanic and Atmospheric Administration 

(NOAA) National Climate Data Center. DCN AD00929. 

FAA. U.S. Federal Aviation Administration (FAA) National Flight Data Center. DCN AD00930. 

USEPA. 2008a. Development of Statistical Weighting Factors for Airport Deicing Category.

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. DCN AD00931. 

USEPA. 2006c. Engineering Site Visit Report for General Mitchell International Airport, 

Milwaukee, WI. U.S. Environmental Protection Agency/Office of Water. Washington, D.C. DCN 

AD00772. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-45 

USEPA. 2006d. Engineering Site Visit Report for Minneapolis-St. Paul International Airport, 

Minneapolis, MN. U.S. Environmental Protection Agency/Office of Water. Washington, D.C. 

DCN AD00793. 

USEPA. 2006e. Engineering Site Visit Report for Denver International Airport, Denver, CO. 

U.S. Environmental Protection Agency/Office of Water. Washington, D.C. DCN AD00779. 

ERG. 2007a. Personal communication (email) between Mary Willett (ERG) and Kevin Gurchak 

(Pittsburgh International Airport). (December 6). DCN AD00873. 

McQueen, R., et al. Development of a Deicer Management System for Akron-Canton Airport. 

DCN AD00894. 

ERG. 2007b. Personal communication (email) between Mary Willett (ERG) and Roy Fuhrmann, 

Minneapolis-St. Paul International Airport. (May 3). DCN AD00872. 

USEPA. 2006f. Sampling Episode Report for Pittsburgh International Airport. U.S. 

Environmental Protection Agency/Office of Water. Washington, D.C. DCN AD00841. 

USEPA. 2006g. Sampling Episode Report for Denver International Airport. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. DCN AD00840. 

USEPA. 2006h. Sampling Episode Report for Albany International Airport. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. DCN AD00842. 

USEPA. 2008b. Sampling Episode Report for Rockford International Airport. U.S. 

Environmental Protection Agency/Office of Water. Washington, D.C. DCN AD00839. 

ERG. 2007c. Personal communication between Mark Briggs (ERG) and New Logic Research, 

Inc., Emmeryville, CA. (June 12). DCN AD00895. 

TRB Airport Cooperative Research Program, 2009. Deicing Planning Guidelines and Practices 

for Stormwater Management Systems ACRP Report No. 14. DCN AD01191. 

New Logic Research. 2001. VSEP Filtration for Glycol Recovery, Application Note. DCN 

AD00897. 

ERG. 2007d. Personal communication (email) between Mary Willett (ERG) and Donald 

Chapman (Cincinnati/Northern Kentucky International Airport). (May 4). DCN AD00867. 

ERG. 2007e. Personal communication (email) between Mary Willett (ERG) and Keith Pass 

(Denver International Airport). (July 12). DCN AD00868. 

ERG. 2007f. Personal communication between Mark Briggs (ERG) and Roger Lamdola (Inland 

Technologies – Canada). (March 19). DCN AD00881. 
Technical Development Document for Proposed Effluent 11. Technology Costs 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 11-46 

USDoD. 2003. U.S. Department of Defense. ESTCP, Mineralization of TNT, RDX, and ByProducts in an Anaerobic Granular Activated Carbon Fluidized Bed Reactor, (April). DCN 

AD00898. 

ERG. 2007g. Personal communication (email) between Mary Willett (ERG) and Mark Sober 

(Albany International Airport). (December 12). DCN AD00865 and AD00866. 

ERG. 2007h. Personal communication (email) between Mary Willett (ERG) and R. McQueen 

(Akron-Canton International Airport). (May 3). DCN AD00863 and AD00864. 

ERG. 2007i. Personal communication between Mark Briggs (ERG) and Aqua-Aerobic Systems, 

Inc., Rockford, IL. (August 31). DCN AD00932. 

RS. 2002. RSMeans. Means Heavy Construction Cost Data, 16th Annual Edition. 

http://www.rsmeans.com DCN AD00899. 

USDoD. 2001. U.S. Department of Defense. Military Construction Program 1391. DCN 

AD00900. 

Perry. 1984. Perry’s Chemical Engineers Handbook, Sixth Edition. http://www.knovel.com 

DCN AD00901. 

USEPA. 2006i. Engineering Site Visit Report for Greater Cincinnati International Airport. U.S. 

Environmental Protection Agency/Office of Water. Washington, D.C. DCN AD00767. 

USEPA. 2006j. Engineering Site Visit Report for Portland International Airport. DCN AD00775. 

Google. 2007. Google Earth Geographical Mapping System. 

Transport Canada. 1998. Transportation Development Center, “Laboratory Testing of Tire 

Friction Under Winter Conditions (TP 13392E).” (May). DCN AD00902. 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

12. NON-WATER QUALITY IMPACTS

 Sections 304(b) and 306 of the Clean Water Act require EPA to consider non-waterquality environmental impacts (including energy requirements) associated with effluent 

limitation guidelines and standards. To comply with these requirements, EPA considered the 

potential impact of the collection and treatment technologies on energy consumption, air 

emissions, and solid waste generation. 

 Section 12.1 discusses the energy requirements for implementing the proposed collection 

and treatment technologies at in-scope airports (defined as commercial airports with 1,000 or 

more jet departures per year). Sections 12.2 and 12.3 discuss the impact of these technologies on 

air emissions and on wastewater treatment sludge generation, respectively. Section 12.4 presents 

the references used in this section. 

12.1 Energy Requirements 

 This subsection discusses the net energy requirements for the selected collection and 

treatment scenarios evaluated by EPA for proposal. Net energy consumption considers electrical 

requirements for pumping collected fluid from centralized deicing pads, and electrical 

requirements for operating the anaerobic fluidized bed (AFB) bioreactors and the aerated ponds 

and fuel requirements for glycol recovery vehicles (GRVs). EPA did not consider electrical 

requirements for the ultrafiltration/reverse osmosis (UF/RO) and mechanical vapor 

recompression (MVR)/distillation recovery and recycle technologies in this analysis since these 

technologies were ultimately not selected as part of the proposed regulatory options. Detailed 

calculations regarding net energy consumption for the collection and treatment technologies are 

provided in a separate memorandum entitled Energy Requirements for ADF Contaminated 

Stormwater Collection and Treatment Alternatives (DCN AD01166). 

 To estimate incremental electrical requirements associated with pumping collected ADF 

to either tanks or ponds, EPA assumed airports would continuously operate three 40-horsepower 

(hp) electric motors during each deicing day. EPA also conservatively assumed that all airports 

would use pumps rather than allow ADF-impacted stormwater to flow by gravity to holding 

tanks or ponds. To estimate electrical use by airport based on the number of deicing days per 

year, EPA developed the following equation: 

yr

days SOFP

day

hr 24

hp

kW 7456.0

pump

HP Electrical Pumping 40pumps 3 ××= ×× (12-1) 

where: 

kW = Kilowatts; and 

SOFP = Snow or other freezing precipitation. 

 Using the equation above and the SOFP days for those airports that EPA assumed would 

install additional collection equipment, total incremental electrical usage associated with the 

proposed rule would be approximately 1.2 million kilowatt hours per year (kWh/yr). 

 EPA developed another relationship between electrical use and chemical oxygen demand 

(COD) removal by the AFB bioreactors based on information provided by Albany International 

(ALB) airport. Using the information from ALB, EPA estimated the electrical requirement for 

July 2009 12-1 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 12-2 

COD removal as approximately 1.3 kWh/lb COD removed. Using this unit rate, EPA estimated 

total electrical requirements to remove COD based on each of the ADF collection scenarios. 

Table 12-1 lists the electrical requirements for the AFBs. 

Table 12-1. Estimated Electrical Requirements for All AFB Treatment Systems 

Regulatory Scenario 

Total COD Removal 

(pounds/yr) 

AFB Electrical 

Requirements 

(kWh/lb COD Removed) 

Total Electrical 

Requirement 

(million kWh/yr) 

20% ADF Capture 7,329,700 1.3 9.5 

40% ADF Capture 15,282,600 1.3 19.9 

60% ADF Capture 34,545,100 1.3 44.9 

 The AFB treatment systems also generate biogas that can be used as a source of heat 

when burned in facility boilers or when converted to electricity using technologies such as 

microturbines or fuel cells. To estimate the potential electricity that could be generated if all 

AFB treatment systems installed microturbines to generate electricity, EPA developed a 

relationship between biogas generation and COD removal based on data provided by ALB 

airport. EPA estimated the AFB reactors will generate approximately 8 cubic feet of biogas per 

pound of COD removed, and the biogas is approximately 60 percent methane. Because one cubic 

foot of methane provides 0.01 therms (1) and 1 therm is equivalent to 29.3 kWh when converted 

to electrical energy (USC, 2007), EPA was able to predict the potential electrical energy 

available from biogas generated by the AFBs treating ADF-contaminated stormwater. Table 12-2 

presents electricity generation from biogas generated by the AFBs. 

Table 12-2. Potential Electricity Generation from AFB Biogas Generation 

Regulatory 

Scenario 

Total COD 

Removal 

(pounds/yr) 

Potential Biogas 

Generation 

(million ft3/yr) 1

Potential Methane 

Generation 

(million ft3/yr) 2

Potential Electrical 

Generation 

(million kWh/yr) 3

20% ADF Capture 7,329,700 57 34 10 

40% ADF Capture 15,282,600 119 71 21 

60% ADF Capture 34,545,100 161 97 47 

1 Calculation based on 8 cubic feet of biogas per lb COD removed. 

2 Assumes biogas is approximately 60% methane per Metcalf and Eddy Wastewater Engineering and Design (9). 3 Calculation based on 100 therms per cubic foot of methane and 29.3 kWh per therm. 

 The comparison of the potential electrical generation from converting biogas to 

electricity to the electrical requirements shown in Table 12-1 indicates that AFB treatment of 

ADF-contaminated stormwater could generate nearly the same amount of electricity that is 

needed to operate the treatment systems. 

 Fuel use by GRVs collecting ADF-contaminated stormwater is another incremental 

energy requirement for compliance with the proposed rule. To estimate incremental diesel fuel 

use by GRVs, EPA obtained annual diesel fuel costs for GRVs from the Airport Deicing 

Questionnaire (USEPA, 2006a) and then estimated diesel fuel use based on the unit cost for 

diesel fuel (e.g., $/gal). According to questionnaire data, one airport spent $17,600 on diesel fuel 

to operate GRVs for recovery of spent ADF and stormwater during the 2004-2005 deicing 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 12-3 

season. This airport collected approximately 20 percent of their applied ADF in stormwater in 

the 2004/2005 deicing season. Based on an average diesel fuel cost of $2.07 per gallon during 

the 2004/2005 deicing season (USDOE, 2006), EPA estimates this airport burned approximately 

8,500 gallons of diesel fuel in GRVs. Based on annual ADF use and size, EPA estimated diesel 

fuel use in GRVs to be 0.08 gal/gal ADF applied. Using this relationship, EPA estimated total 

incremental No. 2 diesel fuel consumption at all in-scope airports installing additional collection 

equipment to be 604,000 gallons per year. This volume is a conservative estimate since it is 

based on an airport that currently use only GRVs to collect ADF-contaminated stormwater (e.g., 

20% ADF collection). If airports installs deicing pads or utilizes plug and pump to collect ADFcontaminated stormwater, GRV usage is expected to be less, and therefore diesel fuel use is also 

expected to be less. 

 EPA compared incremental diesel fuel use by GRVs at all airports to diesel fuel use on a 

national basis. According to the Energy Information Administration, approximately 25.4 million 

gallons per day of No. 2 diesel fuel was consumed in the United States in 2005 (USDOE, 2006). 

Total annual diesel fuel use by GRVs to collect ADF-contaminated stormwater at airports would 

account for less than 0.005 percent of the daily diesel fuel use on a national level. 

12.2 Air Emissions

 Additional air emissions as a result of the proposed rule can be attributed to added diesel 

fuel combustion by GRVs collecting ADF-contaminated stormwater, from additional jet engine 

taxi time related to deicing pads, and from anaerobic treatment of ADF. Emissions from these 

sources are discussed below. 

Emissions From GRV Collection 

 As discussed in Section 12.1, EPA conservatively estimated that GRVs collecting ADFcontaminated stormwater at airports will consume an additional 604,000 gallons per year of 

No. 2 diesel fuel.. To estimate air emissions related to combustion of No. 2 diesel fuel in the 

internal combustion engines on GRVs, EPA used published emission factors for internal 

combustion engines (USEPA, 2006b). The Agency selected emission factors for gasoline and 

diesel industrial engines rather than on-road mobile sources because the emission factors for the 

industrial engines include equipment such as fork lifts and industrial sweepers and scrubbers 

(USEPA, 2006b). To estimate emissions from the GRVs, EPA first converted the additional 

604,000 gallons of diesel fuel to million British Thermal Units (MMBtu) and then applied the 

appropriate emission factors (USEPA, 2006b. Table 12-3 shows the estimated increase in criteria 

pollutant emissions associated with the use of GRVs. Additional details regarding emissions 

from GRVs are contained in a memorandum titled “Air Emissions from Airport Deicing 

Collection and Treatment Technologies” (DCN AD01165). 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 12-4 

Table 12-3. Estimated Incremental Criteria Pollutant Emissions from GRVs 

Criteria Pollutant 

Diesel Fuel 

Consumption in 

GRV Internal 

Combustion Engine 

(gal/yr) 

Diesel Fuel 

Consumption in GRV 

Internal Combustion 

Engine 

(MMBtu/yr) 1

Emission Factor for 

Diesel Fuel 

Combustion in the 

Internal Combustion 

Engine 2

Estimated Annual 

Emissions from 

GRVs Burning Diesel 

Fuel 

(tons/yr) 

Carbon Monoxide 604,000 84,500 0.95 40 

Carbon Dioxide 604,000 84,500 164 6,900 

Nitrogen Oxides 604,000 84,500 4.41 186 

Sulfur Dioxide 604,000 84,500 0.29 12 

PM10 604,000 84,500 0.31 13 

1 Heat content of diesel fuel is approximately 140,000 Btu/gal per Perry’s Chemical Engineers Handbook, 6th 

Edition, Figure 9-4. 

2 Emission factors from EPA Compilation of Emission Factors AP-42. 

PM10 – Particulate matter less than 10 um. 

 The annual emissions provided in Table 12-3 indicate that an additional 4,781 tons per 

year of carbon dioxide will be emitted from GRVs combusting additional diesel fuel to comply 

with the proposed rule. Carbon dioxide is the primary greenhouse gas attributed to climate 

change; although 6,900 additional tons per year appears to be considerable, the amount is very 

small relative to other sources. For example, in 2006, industrial facilities combusting fossil fuels 

emitted 948 million tons of CO2 equivalents. An additional 6,900 tons per year from GRVs is 

less than a 0.001 percentage increase in the overall CO2 emissions from all industrial sources 

(USEPA, 2008). 

Emissions From Transportation to Aircraft Deicing Pads 

 To estimate aircraft emissions associated with the additional time spent taxiing to and 

from newly installed deicing pad and idling during deicing, EPA used the seven busiest airports 

where deicing pads would likely be installed to comply with the proposed rule. Those airports 

include Boston Logan, Cleveland-Hopkins, Newark Liberty, Washington Dulles, New York’s 

LaGuardia and Kennedy airports, and Chicago O’Hare. To estimate aircraft emissions for each 

airport from transportation to newly installed deicing pads, input files such as departure 

information, types of aircraft being deiced, and deicing days were compiled and applied to the 

Emissions and Dispersion Modeling System (EDMS). EDMS is an emission estimating tool 

developed by the U.S. Department of Transportation’s Federal Aviation Administration (FAA) 

(USDOT, 2008). This computer model integrates all airport emission sources, mobile and 

stationary, into a single model. EDMS requires aircraft-specific activity data — specifically, the 

make and model number of the aircraft used by the seven airports included in this assessment. 

For this assessment, EPA obtained 2007 aircraft-specific activity data from the U.S. Department 

of Transportation's Bureau of Transportation Statistics (BTS) T-100 data set for each of the 

seven airports included in this study (USDOT, 2008). 

 However, the aircraft make and model data from the BTS do not match exactly with the 

aircraft make and model available in the EDMS model, so EPA developed an aircraft crosswalk 

to match the BTS data to the aircraft in the EDMS model. As shown in Table 12-4, the crosswalk 

was able to match 89 percent of the aircraft to the EDMS model, Table 12-5 shows that the 

matched aircraft accounted for 97 percent of the activity based on landing and take-off cycles 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 12-5 

(LTOs). Many of the aircraft that were not matched were helicopters and smaller planes that 

probably do not account for a significant portion of deicing activities, and excluding them from 

this assessment is probably warranted. After matching either the aircraft make or model, EPA 

used either the associated default engine in EDMS or the most common engine in the model 

runs. 

Table 12-4. BTS to EDMS Matching Based on Aircraft 

Airport Total Aircraft Matched Aircraft Percent Match 

Boston Logan 71 64 90% 

Cleveland-Hopkins 50 46 92% 

Newark Liberty 67 55 82% 

Washington Dulles 65 58 89% 

New York Kennedy 62 53 85% 

New York LaGuardia 40 39 98% 

Chicago O’Hare 57 53 93% 

Totals 412 368 89% 

Table 12-5. BTS to EDMS Matching Based on LTOs 

Airport Total LTO Matched LTO Percent Match 

Boston Logan 185,524 162,737 88% 

Cleveland-Hopkins 114,457 114,438 100% 

Newark Liberty 214,716 212,650 99% 

Washington Dulles 153,842 149,753 97% 

New York Kennedy 184,576 168,438 91% 

New York LaGuardia 192,837 192,193 100% 

Chicago O’Hare 462,930 460,577 99% 

Totals 1,508,882 1,460,786 97% 

 Typically, the EDMS input file quantifies aircraft activity relative to an aircraft’s LTO 

cycle. The cycle begins when the aircraft approaches the airport on its descent from cruising 

altitude, then lands and taxis to the gate, where it idles during passenger deplaning. The cycle 

continues as the aircraft idles during passenger boarding, taxis back out onto the runway, takes 

off, and ascends (climbout) to cruising altitude. Thus, the six specific operating modes in an LTO 

cycle noted in Figure 12-1 are the following: 

• Approach; 

• Taxi/idle-in; 

• Taxi/idle-out; 

• Idling; 

• Takeoff; and 

• Climbout. 

 The LTO cycle provides a basis for calculating aircraft emissions. During each mode of 

operation, an aircraft engine operates at a specific power setting and fuel consumption rate for a 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

given aircraft make and model. Emissions for one complete cycle are calculated using emission 

factors for each operating mode for each specific aircraft engine combined with the typical 

period of time the aircraft is in the operating mode. 

Figure 12-1. Landing and Take Off Cycle 

 For this assessment, EPA ran the EDMS model using default time-in-mode values for 

each component of the LTO cycle. Next, the Agency adjusted the time-in-mode values in the 

model to account for additional time spent traveling to the deicing pad (15 minutes), engine 

idling while deicing (30 minutes), and taxing away from the deicing pad (15 minutes) and reran 

the model with these adjusted time-in-mode values. Then, EPA subtracted the baseline model 

run from the second model run to estimate the additional emissions associated with deicing as 

noted in the following equation: 

 AExi = ABxi – Bxi (12-2) 

where: 

AExi = Annual additional emission associated aircraft deicing for airport i and 

pollutant x (tons per year); 

ABxi = Annual emission using time in mode values increased to account for time 

spent taxiing to and from the deicing pad and idling at the deicing pad for 

airport i and pollutant x (tons per year); and 

Bxi = Baseline annual emissions assuming no deicing activities for airport i and 

pollutant x (tons per year). 

 Because the BTS data are in terms of annual LTOs, EPA adjusted these values to reflect 

the SOFP days for each airport by multiplying the annual values by the SOFP days divided by 

365 days per year, as noted in the following equation: 

365

SPAE E ixi

xi

× = (12-3) 

where: 

Exi = Additional emission associated aircraft deicing for airport i and pollutant x

for SOFP period (tons/SOFP period); 

AExi = Annual additional emission associated aircraft deicing for airport i and 

pollutant x (tons per year); 

July 2009 12-6 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 12-7 

SPi = SOFP period for airport i (days); and 

365 = Days per year. 

Table 12-6 presents these incremental emission estimates for criteria pollutants for each of the 

seven airports used in the modeling program. 

Table 12-6. Incremental Criteria Pollutant Emissions Associated with Aircraft Deicing 

Operations 

Airport 

CO 

(tons/yr) 

THC 

(tons/yr) 

VOC 

(tons/yr) 

NOX

(tons/yr) 

SOX

(tons/yr) 

PM10

(tons/yr) 

Boston Logan 118 13 14 21 5 0.4 

Cleveland-Hopkins 93 12 13 15 4 0.3 

Newark Liberty 111 14 16 21 5 0.5 

Washington Dulles 67 8 8 11 3 0.2 

New York Kennedy 94 12 13 17 4 0.4 

New York LaGuardia 62 6 6 11 3 0.2 

Chicago O’Hare 357 35 38 61 15 1 

CO – Carbon monoxide. 

THC – Total hydrocarbons. 

VOC – Volatile Organic Compounds. 

NOX – Nitrogen Oxides. 

SOX – Sulfur Dioxide. 

PM10 – Particulate Matter less than 10 um. 

 EPA also estimated total annual LTO aircraft emissions for the seven airports to compare 

aircraft emissions associated only with deicing. Table 12-7 compares the total estimated LTO 

emissions and the percentage increase in emissions from aircraft to comply with the proposed 

rule. The data indicate that the proposed rule could increase carbon monoxide emissions from 

aircraft at the impacted airports by as much as 6.9 percent due to additional ground-time needed 

for pad deicing. Although the annual percentage increase in criteria pollutant emissions from the 

seven airports included in this analysis is a concern, the actual increase in emissions (e.g., 903 

tons per year of carbon monoxide) is insignificant when compared to total criteria pollutant 

emissions for the aircraft sector. For example, in 2002, EPA estimated total carbon monoxide 

emissions from the aircraft sector at approximately 260,000 tons (USEPA, National Emissions 

Inventory website). Because increased criteria pollutant emissions resulting from additional 

aircraft deicing time account for less than a 0.3 percentage increase in the aircraft sector annual 

criteria pollutant emissions, EPA believes the very small increase is justifiable given the benefits 

from the proposed rule. 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 12-8 

Table 12-7. Comparison of Total Annual LTO Aircraft Emissions to Emissions Resulting in 

Deicing Operations 

Emissions 

CO 

(tons/yr) 

THC 

(tons/yr) 

VOC 

(tons/yr) 

NOX

(tons/yr) 

SOX

(tons/yr) 

PM10

(tons/yr) 

Estimated Total Annual 

Aircraft LTO Emissions for 

Seven Airports 

13,174 1,464 1,591 13,376 1,135 107 

Estimated Total Emissions 

from Deicing Operations for 

Seven Airports 

903 99 108 158 38 3 

Estimated Percent Increase 

in LTO Aircraft Emissions 

Due to Proposed Rule 

6.9% 6.8% 6.8% 1.2% 3.4% 2.8% 

CO – Carbon monoxide. 

THC – Total hydrocarbons. 

VOC – Volatile Organic Compounds. 

NOX – Nitrogen Oxides. 

SOX – Sulfur Dioxide. 

PM10 – Particulate Matter less than 10 um. 

Emissions from AFB Treatment Systems 

 Anaerobic digestion of glycols found in ADF contaminated stormwater generate biogas 

containing approximately 60 percent methane and 40 percent carbon dioxide. Airports installing 

AFBs for treatment of ADF contaminated stormwater are expected to burn a portion of the gas in 

on-site boilers in order to maintain reactor temperature. The remainder of gas can be either 

combusted in a microturbine for electricity generation or flared. Regardless of the combustion 

technology, nearly all biogas generated by AFBs is converted to carbon dioxide, the primary 

green house gas. Table 12-8 shows biogas generation and potential carbon dioxide emissions 

from AFB treatment systems for the proposed collection scenarios. 

Table 12-8. Potential Air Emissions from AFB Treatment Systems 

Regulatory Scenario 

Total COD Removal 

(pounds/yr) 

Potential Biogas 

Generation 

(million ft3/yr) 1

Potential Carbon Dioxide 

Generation 

(tons/yr) 2

20% ADF Capture 7,329,700 57 3,700 

40% ADF Capture 15,282,600 119 7,600 

60% ADF Capture 34,545,100 161 17,300 

1

 Calculation based on 8 cubic feet of biogas per lb COD removed. Biogas is 60% methane and 40% CO2 (Metcalf 

& Eddy, 1979) 

2

 Assumes 99.9 percent of biogas is converted to CO2 during combustion. 

 Carbon dioxide is the primary greenhouse gas attributed to climate change; although 

17,300 additional tons per year for 60% ADF capture appears to be considerable, the amount is 

very small relative to other sources. For example, in 2006, industrial facilities combusting fossil 

fuels emitted 948 million tons of CO2 equivalents. An additional 17,300 tons per year of carbon 

dioxide from AFB treatment is less than 0.002 percent of the annual industrial carbon dioxide 

emissions nationwide. 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 12-9 

12.3 Solid Waste Generation 

 AFB bioreactors will generate sludge that will require disposal, likely in an off-site 

landfill. To estimate annual sludge generation by the AFB bioreactors that may be installed at 

airports to treat ADF-contaminated stormwater, EPA first estimated the potential COD removal 

for the proposed collection and treatment scenarios and then applied published anaerobic 

biomass yield information (Metcalf & Eddy, 1979) to estimate total sludge generation on a 

national basis. The biomass yield calculation, which simply multiplies the COD removal by the 

yield, is a rough method of estimating sludge generation and does not account for other factors 

such as degradation or inorganic material (e.g., AFB media) that may be entrained into the 

sludge. However, this method does provide an order of magnitude estimate of sludge generation 

that can be compared to other types of common biological treatment systems to determine if 

AFB sludge generation would be unusually high at airports treating ADF-contaminated 

stormwater. 

 Table 12-9 shows the total COD removal from each collection and treatment scenario and 

the estimated sludge that would likely require disposal. This sludge is expected to be nonhazardous and can be disposed in a municipal landfill. Detailed calculations showing how EPA 

estimated biomass amounts are provided in a memorandum entitled Estimated Sludge 

Generation from AFBs Treating ADF-Contaminated Stormwater (DCN AD01164). 

Table 12-9. Estimated Sludge Generation from AFB Bioreactors Treating ADF 

Contaminated Stormwater 

Regulatory Scenario 

Total COD Removal 

(pounds/yr) 1

Anaerobic Biomass Yield

(lbs biomass/lb COD 

removed) 2

Total Sludge Generation

(tons/yr) 

20% ADF Capture 7,329,700 0.03 110 

40% ADF Capture 15,282,600 0.03 229 

60% ADF Capture 34,545,100 0.03 518 

1 Total COD removal from all AFB bioreactors which may be installed at airports. 

2 Biomass yield from Metcalf and Eddy. 

 To provide some perspective on the potential total amount of biomass produced annually 

by the AFB biological reactors treating ADF-contaminated stormwater, EPA compared the total 

biomass generation data in Table 12-9 with the national biosolids estimates for all domestic 

wastewater treatment plants throughout the United States. According to EPA’s Municipal and 

Solid Waste Division, approximately 8.2 million dry tons of biosolids will be produced in 2010 

(USEPA, 1999). Using the highest biosolids generation amount shown in Table 12-9 (518 

tons/yr), EPA estimates that AFB bioreactors treating ADF-contaminated stormwater will 

increase biosolids generation in the United States by less than 0.01 percent. EPA believes this 

very small percentage increase in biosolids generation is justifiable based on the benefits of the 

Aircraft Deicing Operations proposed rule. 

12.4 References 

USC. 2007. U.S. Code Title 15, Commerce and Trade, Chapter 6. (January). Weights and 

Measures and Standard Time. DCN AD00918. 
Technical Development Document for Proposed Effluent 12. Non-Water Quality Impacts 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 12-10 

USEPA. 2006a. Airport Deicing Questionnaire Database. U.S. Environmental Protection 

Agency/Office of Water. Washington, D.C. DCN AD00927. 

USDOE. 2006. U.S. Department of Energy, Energy Information Administration. No. 2 Fuel Oil 

All Sales/Deliveries by Prime Supplier. DCN AD00919. 

USEPA. 2006b. Compilation of Air Pollutant Emission Factors (AP-42), Fifth Edition, Section 

3.3. DCN AD00920. 

USEPA. 2008. Inventory of U.S. Greenhouse gas Emissions and Sinks: 1990 – 2006. U.S. 

Environmental Protection Agency/Office of Water. Washington, D.C. EPA 430-R-08-05 (April). 

DCN AD00921. 

USDOT. 2006. U.S. Department of Transportation, Federal Aviation Administration, Emissions 

and Dispersion Modeling System, Version 4.5. Washington, D.C. (June). DCN AD00922. 

USDOT. 2008. Bureau of Transportation Statistics, T-100 Segment, 2007. Washington, D.C. 

DCN AD00923. 

USEPA. National Emissions Inventory Air Pollutant Emission Trends Web Site 

www.epa.gov/ttn/cheif/trends. 

Metcalf and Eddy. 1979. Wastewater Engineering, Treatment/Disposal/Reuse, Second Edition. 

McGraw Hill Press. DCN AD00924. 

USEPA. 1999. Biosolids Generation, Use and Disposal in the United States. U.S. Environmental 

Protection Agency/Office of Water. Washington, D.C. EPA 530D-R-99-009. DCN AD00925. 
Technical Development Document for Proposed Effluent 13. Regulatory Option Selection 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 13-1 

13. REGULATORY OPTION SELECTION

 This section presents the regulatory options evaluated by EPA for the Airport Deicing 

Category and discusses the factors considered in determining the selected option for Best 

Available Technology Economically Achievable (BAT) and New Source Performance Standards 

(NSPS). Factors considered include reductions in pollutant discharges to the environment, costs 

to the industry, size of airports involved, deicing practices used by the airports, changes to 

deicing practices required, and non-water-quality environmental impacts. EPA is not setting Best 

Practicable Control Technology Currently Available (BPT), Best Control Technology (BCT), 

Pretreatment Standards for Existing Sources (PSES) or Pretreatment Standards for New Sources 

(PSNS) for this point source category at this time. 

 The regulatory option selected provides the technology basis of the effluent limitation 

guidelines and standards (ELGs) presented in this section. Owners or operators of airports 

subject to these regulations would not be required to use the specific stormwater collection and 

treatment technologies selected by EPA to establish the ELGs. Rather, an airport could choose to 

use any combination of operational changes, stormwater collection technologies, and stormwater 

treatment or control technologies to comply with the limitations and standards, provided the 

limitations and standards are not achieved through prohibited dilution. 

 Section 13.1 discusses EPA’s approach in developing the regulatory options considered 

and Section 13.2 presents the rationale for the options selected under BAT and NSPS. 

13.1 Regulatory Options Evaluated

 Section 6 of this document summarizes EPA’s estimates of the amount of airfield and 

aircraft deicing chemicals currently used by U.S. commercial airports. Based on these usage 

estimates, and as described in Section 10, EPA assessed the potential current direct discharge 

loadings of five-day biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) 

from both airfield and aircraft operations (referred to as baseline loadings and presented in 

EPA’s Airport Deicing Loadings Calculation memorandum (ERG, 2008a). EPA found that only 

34 percent of the baseline COD load is estimated to come from airfield operations. In addition, 

airfield deicing operations are likely to occur over a greater drainage area than aircraft deicing 

operations alone. As such, the volume of deicing stormwater potentially generated from airfield 

operations can be large, and collecting and controlling that stormwater may not be feasible or 

cost-effective. EPA evaluated estimated costs for collecting and treating all deicing stormwater 

at surveyed airports, rather than stormwater from aircraft deicing operation areas only, and found 

that the potential costs were prohibitive (see Section 11.3.3.2). Because the majority of COD 

discharge from airport deicing operations is believed to originate from aircraft deicing/anti-icing 

operations, and collecting and controlling airfield deicing stormwater appears to be costprohibitive, EPA’s regulatory options focused on aircraft deicing operations. 

 As described in Section 9, EPA evaluated three different ADF collection and treatment 

scenarios for aircraft deicing operations: 

• 20% collection and treatment scenario uses glycol recovery vehicles (GRVs) 

for deicing stormwater collection and anaerobic fluidized bed (AFB) treatment for 

deicing stormwater control; 
Technical Development Document for Proposed Effluent 13. Regulatory Option Selection 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 13-2 

• 40% collection and treatment scenario uses GRVs in combination with blockand-pump technology for deicing stormwater collection and AFB treatment for 

deicing stormwater control; and 

• 60% collection and treatment scenario uses centralized deicing pads for deicing 

stormwater collection and AFB treatment for deicing stormwater control. 

 EPA selected AFB treatment as the basis for BAT. The other three wastewater treatment 

technologies that EPA considered (UF/RO, MVR/distillation, and aerobic biological treatment 

ponds) were less effective at pollutant removal compared to AFB systems and are described in 

Section 8.2. In addition, treating spent ADF with the mechanical methods, UF/RO and 

MVR/distillation results in a concentrated waste stream that also must be disposed of. While 

these technologies have potential as a part of an airport's pollutant control strategy, they are not 

as effective as AFB when used as stand-alone treatment options, i.e. the pollutant removals they 

achieve are not as great as the removals achieved by AFB systems. 

 Aerobic biological treatment ponds were not selected as the technology basis for BAT for 

mainly logistical reasons. The ponds require large areas for installation, and the normal 

operations of these systems require treatment for many months after the end of the annual 

deicing season, before the wastewater can be discharged. Additionally, FAA discourages the 

installation of new stormwater detention ponds at airports, as they can be a lure for migratory 

birds. In those situations, birds and aircraft are safety hazards to each other. For airports with 

existing detention ponds, however, where adequate storage capacity is available, aerated pond 

systems may be able to provide efficient treatment that meets the standard. 

 Since collection and treatment of airfield deicing stormwater may not be practical, EPA 

evaluated whether there were other regulatory options that could control the discharge of airfield 

load and/or toxicity. Information collected by EPA during the airport site visits indicated options 

might be to limit the amount of urea or eliminate the use of urea as an airfield deicing chemical 

and replace it with other, less toxic products. Because other less toxic products (e.g., potassium 

acetate) are available for substitution, most airports have already made the substitution, and the 

total cost of substitution is not prohibitive, EPA is including as part of each regulatory option a 

numeric effluent limit on ammonia in stormwater associated with deicing activities. Ammonia 

was chosen to be a surrogate for urea. 

 EPA evaluated the costs, loading reductions, and economic impacts associated with each 

ADF collection and treatment scenario for those airports included in EPA’s airport 

questionnaires. As discussed above, a BAT determination must be “economically achievable.” 

In order to meet this criteria EPA was required to look at a subset of the U.S. airport population, 

a total of over 3,300 public airports. 

 Early in the regulatory development process, EPA focused on deicing activities at 

primary airports, particularly those with extensive jet traffic. Operators of general aviation 

aircraft, as well as smaller commercial non-jet aircraft, typically suspend flights during icing 

conditions, whereas commercial airlines are much more likely to deice their jets in order to meet 

customer demands. 
Technical Development Document for Proposed Effluent 13. Regulatory Option Selection 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 13-3 

 Based on the survey results, EPA estimated that 320 airports conduct deicing operations. 

The Agency analyzed various industry characteristics that would be an indicator of affordability 

for the candidate control and treatment technologies. This included a review of the relative sizes 

of various airports (based on annual departures), the levels of deicing activity, traffic 

characteristics (i.e. passenger vs. cargo operations), the extent of pollution controls and treatment 

in place, and the costs of various technologies. EPA further classified airports based on the 

number of annual jet departures. EPA found that there were some primary airports with high 

percentages of non-jet traffic, and so it excluded airports with less than 1,000 annual jet 

departures from the scope of the proposed rule. These airports have a higher proportion of 

propeller-aircraft flights, which are typically delayed or cancelled during icing conditions. The 

Agency estimated that the 218 larger primary airports perform most of the deicing operations, 

and applying the regulation to this group would result in a substantial level of pollutant reduction 

while being economically achievable for the industry. Table 13-1 presents the regulatory options 

EPA evaluated for the Airport Deicing Category. 

Table 13-1. Regulatory Options Evaluated for the Airport Deicing Category 

Option Option Description 

Airports Subject to 

Option 

1 • All primary commercial airports with over 1,000 jet departures that conduct 

deicing per year and are not General Aviation/Cargo (GA/C) are in scope; 

• Airports with ≥10,000 departures per year required to collect and control 

20% of spent ADF and treat to numeric limit; and 

• All in-scope airports must meet effluent limit for ammonia or certify use of 

non-urea-based pavement deicers. 

110 

2 • All primary commercial airports with over 1,000 jet departures that conduct 

deicing per year and are not GA/C are in scope; 

• Airports with ≥10,000 departures per year required to collect and control 

40% of spent ADF and treat to numeric limit; and 

• All in-scope airports must meet effluent limit for ammonia or certify use of 

non-urea-based pavement deicers. 

110 

3 • All primary commercial airports with over 1,000 jet departures that conduct 

deicing per year and are not GA/C are in scope; 

• Airports with ≥10,000 departures per year required to collect and control 

20% of spent ADF and treat to numeric limit; 

• Airports with ≥460,000 gallons of ADF usage per year are required to collect 

and control 60% of spent ADF and treat to numeric limit; 

• All in-scope airports must meet effluent limit for ammonia or certify use of 

non-urea-based pavement deicers. 

110 

(14 airports subject to 

60% requirement, 96 

airports subject to 

20% requirement) 

4 • All primary commercial airports with over 1,000 jet departures that conduct 

deicing per year and are not GA/C are in scope; 

• Airports with ≥1,000 jet departures per year required to collect and control 

20% of spent ADF and treat to numeric limit; 

• Airports with ≥460,000 gallons of ADF usage per year are required to collect 

and control 60% of spent ADF and treat to numeric limit; 

• All in-scope airports must meet effluent limit for ammonia or certify use of 

non-urea-based pavement deicers. 

218 

(14 airports subject to 

60% requirement, 204 

airports subject to 

20% requirement) 

Note: All references to ADF are for normalized ADF, which is ADF less any water added by the manufacturer or 

customer before ADF application. 

 EPA used the following criteria to frame the regulatory options and the rationale for their 

use: 
Technical Development Document for Proposed Effluent 13. Regulatory Option Selection 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 13-4 

 Primary commercial airport criterion. EPA focused on this category of airports 

because they conduct the most operations, are expected to operate throughout the winter, and can 

apply for funding. General aviation airports generally do not operate as many flights and will 

often suspend operations during inclement weather. 

Annual total aircraft departures criterion. EPA evaluated different annual departure 

levels in developing the regulatory options to assess the benefit and impact of encompassing 

more or fewer small/non-hub airports. 

 Annual jet departures criterion. Based on airport contact information, most aircraft 

deicing operations occur on jet aircraft. Smaller non-jet aircraft are generally either stored in 

hangers before winter flights or are grounded during inclement weather. EPA selected a 

minimum number of jet departures to ensure that the airports considered for regulation would 

conduct deicing regularly through out the winter season and thereby reflect airports with the 

majority of COD load. 

 Annual ADF usage criterion. EPA based this criterion on the relationship between ADF 

usage and the economic impact of the costs to comply with the 60 percent capture and treatment 

scenario. Many of the large ADF usage airports that have evaluated their deicing operations and 

have implemented best demonstrated technologies are achieving 60 percent capture and 

treatment. EPA selected this criterion to include the large ADF usage airports that are not 

currently addressing their deicing operations. 

13.2 Option Selection

 EPA evaluated the following factors in selecting options: 

 Reductions in pollutant discharges to the environment. EPA evaluated current direct 

discharge of COD load (at baseline) and under the various regulatory options (Section 10 

presents capture and treatment scenario load removals by airport and Table 13-2 summarizes the 

regulatory option reductions); 

 Costs to the industry. EPA’s cost analysis assessed the capital, annual operating and 

maintenance (O&M), and annualized costs associated with each regulatory option to assess the 

impact of those costs compared to total annual revenue by airport (Section 11 presents airport’s 

annualized costs by capture and treatment scenario and Table 13-2 summarizes the regulatory 

option costs); 

 Size of the airport. EPA used departure data, Bureau of Transportation Statistics (BTS) 

hub size designations, and small business definitions to assess the size of the airports considered 

under the various regulatory options (airport size designations are discussed in the Economic 

Analysis document (USEPA, 2009)); 

 Deicing practices used by the industry. EPA assessed current airport deicing operations 

and their impact on direct discharges to determine an existing collection and treatment level for 

each airport evaluated (see Section 10.5.2 discussion); and 
Technical Development Document for Proposed Effluent 13. Regulatory Option Selection 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 13-5 

 Changes to deicing practices required. EPA used all of the airport operations data 

collected to date to profile the best demonstrated practices and technologies currently in use for 

airport deicing operations and to compare to the existing practices in use. 

 Table 13-2 summarizes several of the factors EPA evaluated for option selection, and 

Sections 13.2.1 through 13.2.3 present EPA’s proposed regulatory option for BAT, PSES/PSNS, 

and NSPS. 

Table 13-2. Factors Evaluated by EPA in Option Selection 

Option 

Option Removals 

(million lbs) 

Option Annualized 

Costs 

(2006 million $) 

Number of Airports with 

Revenue Impact >3% of 

Annual Revenue 

Small Airports 

with Revenue 

Impact >3% 

1 26.4 36.4 9 3 

2 36.2 110.1 20 3 

3 44.6 91.3 11 3 

4 46.7 105.0 57 11 

Each of the regulatory options evaluated include replacement of urea with potassium acetate as 

an airfield deicing chemical. A breakout of the load removals and costs associated with urea 

replacement are shown below in Table 13-3. 

Table 13-3. Urea Replacement Load Removals and Costs 

Replacement of Urea for Airfield Pavement Deicing

Description 

Airports Subject 

to Option 

COD Removal 

(million lbs) 

Ammonia 

Removal 

(million lbs) 

Annual Removal 

Cost 

(2006 Million $) Removal $/lb

No use of urea 

(product sub.) 

218 12.7 4.7 $5.7 $0.26 

13.2.1 BAT 

 Effluent limitation guidelines based on BAT represent the best available treatment 

performance for deicing operations that is economically achievable. The Clean Water Act 

(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. Based on 

section 304(b)(2)(B) of the CWA, the factors considered in assessing BAT include: 

• The age of equipment and facilities involved; 

• The process used; 

• Process changes required; 

• Engineering aspects of control technologies; 

• The cost of achieving effluent reduction; 

• Non-water quality environmental impacts (including energy requirements); and 

• Other factors the Administrator deems appropriate. 
Technical Development Document for Proposed Effluent 13. Regulatory Option Selection 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 13-6 

 The Agency retains considerable discretion in assigning the weight to be accorded these 

factors. BAT may include process changes or internal controls, even when these technologies are 

not common industry practice. 

 Table 13-1 lists the BAT regulatory options considered by the Agency. Analysis of the 

benefits of the collection and treatment scenarios evaluated by EPA in reducing pollutant 

discharges to the environment, the cost to the industry, and the non-water quality environmental 

impacts are described in Sections 10, 11, and 12, respectively. The Economic Analysis document 

(USEPA, 2009) describes the economic impact of these scenarios on airports and airlines, 

including impacts to small airports. 

 EPA evaluated the costs and economic impacts associated with each option and 

determined that three of the options were economically achievable. After considering the 

pollutant load removals, non-water quality impacts, and potential impact on small airports, EPA 

selected Option 3. This option requires 60 percent collection and treatment for those airports 

with the largest ADF usage (460,000 gallons or more annually) and 20 percent collection and 

treatment for those airports with greater than 10,000 departures per year. EPA selected Option 3 

because it provides the highest level of ADF- and urea-related COD removal, while also being 

economically achievable, of the four options crafted by EPA. This option will require that high 

ADF-usage airports that have not instituted deicing operation controls do so, leveling the playing 

field with those large ADF usage airports that have already invested in collection and control 

technologies. 

13.2.2 PSES/PSNS 

 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). 

The CWA required pretreatment for pollutants that pass through POTWs in amounts that would 

exceed direct discharge of effluent limitations or limit POTW sludge management alternatives, 

including the beneficial use of sludges on agricultural lands. Pretreatment standards are to be 

technology-based and analogous to BAT for removal of priority and nonconventional pollutants. 

 Section 307(c) of the CWA requires EPA to promulgate PSNS at the same time that it 

promulgates NSPS. New indirect discharging facilities, like new direct discharging facilities, 

have the opportunity to incorporate the best available demonstrated technologies, including 

process changes and in-plant treatment technologies that reduce pollution to the maximum extent 

feasible. Pretreatment standards for new sources are to be technology-based and analogous to 

NSPS for the removal of priority and nonconventional pollutants. 

 EPA is not proposing to set PSES or PSNS at this time for the Airport Deicing Category. 

The main pollutants of concern for this category are BOD5 and COD. EPA is proposing a 

biological treatment process (AFB) as BAT for direct discharges. POTWs are specifically 

designed to treat BOD5 and COD using a biological treatment process (either aerobic or 

anaerobic) and thus both the BAT and POTW technologies are equivalent. Therefore, EPA does 

not believe that regulation is warranted for indirect discharges. As discussed in Section 5, over 

62 commercial airports nationwide are currently indirectly discharging their ADF stormwater to 

a POTW either in place of or in addition to direct discharge and EPA anticipates that this 

practice will continue where practical. 
Technical Development Document for Proposed Effluent 13. Regulatory Option Selection 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 13-7 

 EPA is not aware of specific pass-through concerns for POTWs accepting airport deicing 

stormwater. EPA is aware that slug loading of deicing stormwater can create POTW upset, and 

many of the airports that discharge indirectly to POTWs have airport-specific requirements on 

allowable BOD5 or COD discharge loading per day and may also have requirements for ramping 

the load up or down over time. This is usually accomplished by storing deicing stormwater in 

retention ponds, detention ponds, lagoons, or tanks and metering the discharge to meet permit 

requirements. 

13.2.3 NSPS 

 The basis for NSPS under Section 306 of the CWA is the “best available demonstrated 

control technology.” New sources have the opportunity to design and install the best and most 

efficient process operations and wastewater treatment systems. Accordingly, Congress directed 

EPA to consider the best demonstrated alternative processes, process changes, in-plant control 

measures, and end-of-pipe wastewater treatment technologies that reduce pollution to the 

maximum extent feasible. 

 NSPS establish quantitative limits on the direct discharge of conventional, priority, and 

nonconventional pollutants to U.S. waters. These standards are based upon the performance of 

specific advanced technologies, but do not specify which technologies must be used to achieve 

compliance. NSPS are applied to individual facilities through NPDES permits issued by EPA or 

authorized states under Section 402 of the CWA. Each facility then chooses its own approach to 

complying with its permits limitations. 

 New sources for airport facilities will include the following: 1) new stand-alone airports 

and 2) new substantially independent airport runways and the departures from those runways. 

 Much of the current air traffic growth has occurred as existing airport expansion 

(including addition of new runways and concourses) at U.S. small, medium, and large hub 

airports. There is also documented expansion at reliever airports located close to major hubs. 

EPA does not anticipate significant new stand-alone airport construction in the near future. 

 EPA evaluated the best demonstrated practices and technologies used by the aviation 

industry and found that the most effective systems include consolidating deicing operations using 

deicing pad facilities and treating collected deicing stormwater through biological treatment prior 

to direct discharge. The Denver International Airport is an excellent example of best practices for 

deicing stormwater collection; the airport designed each of its runways with its own deicing pad 

system and currently collects approximately 68 percent of their applied ADF for on-site glycol 

recycle and recovery prior to indirect discharge. The Albany Airport is the basis for best 

treatment practices prior to direct discharge using an AFB biological treatment system. EPA has 

therefore selected the 60 percent collection and treatment scenario as best demonstrated practice 

for the industry and is setting NSPS as 60 percent capture of available ADF with direct discharge 

effluent limitations based on AFB treatment. The performance level of NSPS is equivalent to 

BAT requirements for large ADF usage airports. Standards for COD are being established for 

new sources consistent with the BAT performance level. In addition, EPA is proposing stringent 

discharge limits on ammonia, based on product substitution for urea-based airfield pavement 
Technical Development Document for Proposed Effluent 13. Regulatory Option Selection 

Limitation Guidelines and Standards for the Airport Deicing Category 

July 2009 13-8 

deicers, consistent with the proposed BAT requirements. Alternatively, facilities may certify use 

of non-urea-based pavement deicers. 

13.3 References

ERG. 2008a. Memorandum from Cortney Itle (ERG) to Brian D’Amico (EPA): Airport Deicing 

Loading Calculations. (April 17). DCN AD01140. 

USEPA. 2009. Economic Analysis for Proposed Effluent Limitation Guidelines and Standards 

for the Airport Deicing Category. U.S. Environmental Protection Agency/Office of Water. 

Washington, D.C. EPA 821-R-09-005. DCN AD01196. 
Technical Development Document for Proposed Effluent 14. Limitation and Standards 

Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-1 

14. LIMITATIONS AND STANDARDS: DATA SELECTION AND CALCULATION

 This section describes the data selection and statistical methodology that EPA used to 

calculate the proposed limitations for the airport deicing point source category. As described in 

this section, the proposed effluent limitations and standards account for variation in treatment 

performance of the model technology. For simplicity, the following discussion refers only to 

effluent limitations guidelines; however, the discussion also applies to new source standards. 

 EPA is proposing limitations for chemical oxygen demand (COD) and ammonia as 

nitrogen (the latter as a compliance alternative), and Section 14.1 briefly describes the pollutant 

parameters. Section 14.2 provides an overview of EPA’s data review and selection process. 

Section 14.3 describes EPA’s data conventions. Sections 14.4 and 14.5 describe the COD and 

ammonia as nitrogen data selected as the basis of the proposed limitations. Section 14.6 

describes the percentile basis and calculations used for the limitations. Section 14.7 describes 

achievability and compliance related to the limitations. Section 14.8 provides references. 

14.1 Selected Pollutant Parameters

 As described in Section 7, there are a number of pollutants associated with the discharge 

from airport deicing operations. EPA is proposing effluent limitations for two pollutant 

parameters, chemical oxygen demand (COD) and ammonia. This section briefly describes the 

pollutant parameters and the chemical analytical methods used to measure their concentrations. 

14.1.1 Chemical Oxygen Demand (COD) 

 COD is a measure of the total organic matter content of both wastewaters and natural 

waters. Measurement of COD can be used to rapidly recognize deterioration in wastewater 

treatment plant performance and the need for corrective action. EPA evaluated data collected by 

the Albany International Airport in New York, and by EPA. EPA evaluated data for chemical 

oxygen demand (COD) that was measured using EPA Method 410.4 and Hach 8000, both of 

which are listed as approved for compliance monitoring in 40 CFR Part 136. EPA determined 

COD using Method 410.4, and Albany Airport used Hach 8000. Data from the two methods are 

directly comparable. 

 Method 410.4 is a colorimetric procedure with a measurement range of 3 to 900 mg/L for 

automated procedures and a measurement range of 20 to 900 mg/L for manual procedures. The 

Hach 8000 method is a colorimetric procedure that utilizes a preliminary digestion procedure and 

can be used for various concentration ranges. A user has the option of purchasing three different 

sets of reagents and standards. The first has a measurement range of 0 to 40 mg/L; the second: 0 

to 150 mg/L; and the third: 0 to 1500 mg/L. The industry data had a lower measurement limit of 

2.0 mg/L. 

14.1.2 Ammonia as Nitrogen (Ammonia) 

 Ammonia as nitrogen (ammonia) is generated as a by-product of the use of urea-based 

products for deicing operations. Ammonia can be directly toxic to fish and other aquatic 

organisms and can reduce ambient dissolved oxygen concentrations in receiving surface waters. 

In the data evaluated for the proposal, ammonia was measured using Methods 350.1 and 350.2, 

both of which are listed as approved for compliance monitoring in 40 CFR Part 136. Albany 
Technical Development Document for Proposed Effluent 14. Limitation and Standards 

Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-2 

Airport supplied data that was generated using Method 350.1 (DCN AD00824), and EPA used 

Method 350.2. Both methods produce comparable results. 

 Method 350.1 is an automated colorimetric method that uses a continuous flow analytical 

system and has a detection range of 0.01 to 2.0 mg/L. Method 350.2 utilizes either colorimetric, 

titrimetric, or electrode procedures to measure ammonia. Method 350.2 has a lower measurement 

range limit of 0.20 milligrams per liter (mg/L) for the colorimetric and electrode procedures and 

a lower measurement range limit of 1.0 mg/L for the titrimetric procedure. 

14.2 Overview of Data Review and Selection

 As described in Sections 14.4 and 14.5, EPA qualitatively reviewed all the available 

influent and effluent data for COD and ammonia. For purposes of limitations development, data 

are defined to be numerical values resulting from laboratory determination of pollutants in 

physical samples collected from influent and effluent wastestreams. A laboratory expresses the 

results of its analysis either numerically or as “not quantitated” for a pollutant in a sample. When 

the result is expressed numerically, then the pollutant was quantitated, or more commonly 

referred to as “detected,” in the sample. The definition includes measured values (e.g., 10 mg/L) 

and values reported as being below some level of quantification (e.g., <10mg/L). The latter are 

often referred to as “non-detected” and are usually reported with a “detection limit.” (EPA also 

uses terms such as “quantitation limit” in other documentation.) The definition of “data” 

excludes estimated values and statistical summaries, such as averaged values. 

 This section describes EPA’s review of the available data. Section 14.2.1 describes the 

criteria that EPA applied in selecting data for the development of the proposed limitations. 

Section 14.2.2 describes other considerations that were evaluated as part of the data review. 

Section 14.2.3 discusses the importance of comments in EPA’s evaluations of the data for the 

final limitations. 

14.2.1 Data Selection Criteria 

 This section describes the criteria that EPA applied in selecting data to use as the basis 

for the proposed effluent limitations. EPA has used these or similar criteria in developing 

limitations and standards for other industries. EPA uses these criteria to select data that reflect 

consistently good performance of the model technology in treating the industrial wastes under 

normal operating conditions. Model technology is technology that is carefully designed and 

diligently operated. The following paragraphs describe the criteria and modifications specific to 

the airport deicing category. 

 One criterion generally requires that the influents and effluents from the treatment 

components represent typical wastewater from the industry, with no incompatible wastewater 

from other sources (e.g., sanitary wastes). Application of this criterion results in EPA selecting 

only those facilities where the commingled wastewaters did not result in substantial dilution, 

unequalized slug loads that result in frequent upsets and/or overloads, more concentrated 

wastewaters, or wastewaters with different types of pollutants than those generated by the 

categorical (i.e., airport deicing) wastewater. 
Technical Development Document for Proposed Effluent 14. Limitation and Standards 

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July 2009 14-3 

 A second criterion typically ensures that the pollutants were present in the influent at 

sufficient concentrations to evaluate treatment effectiveness. To evaluate whether the data meet 

this criterion for the final rule, EPA often uses a “long-term average test” for sites where EPA 

possesses paired influent and effluent data. EPA has used such comparisons in developing 

regulations for other industries, e.g., the Iron and Steel Category (EPA 2002). The test looks at 

the influent concentrations to ensure a pollutant is present at sufficient concentration to evaluate 

treatment effectiveness. If a pollutant fails the test (i.e., not present at a treatable concentration), 

EPA excludes the data for that pollutant at that facility from its long-term average and variability 

calculations. In this manner, EPA would ensure that the limitations resulted from treatment and 

not simply the absence or substantial dilution of that pollutant in the wastestream. If industry 

supplies EPA with effluent data, but not the corresponding influent data, EPA may choose to use 

the effluent data without performing a long-term average test provided EPA determines that the 

pollutant would have been present at consistently treatable concentrations at the facility. This 

approach would satisfy EPA’s objective to include as much data from as many facilities as 

possible in the calculation of limits. 

 A third criterion requires that the facility must have the model treatment technology and 

demonstrate consistently diligent operation. Application of this criterion typically eliminates any 

facility with treatment other than the model technology. Exceptions are generally rare, but may 

include facilities with treatment, or performance, that is equivalent to the model technology. EPA 

generally determines whether a facility meets this criterion based upon personal visits, its ability 

to comply with its existing discharge requirements, discussions with facility management, and/or 

comparison to the performance of treatment systems at other facilities. EPA often contacts 

facilities to determine whether data submitted were representative of normal operating conditions 

for the facility and equipment. As a result of this review, EPA typically eliminates facilities that 

experience repeated operating problems with their treatment systems. In addition, EPA typically 

excludes data when the facility has not optimized its treatment. For example, facilities may use 

the model technology as a pretreatment step before sending the wastewater to a publicly owned 

treatment works (POTW), and consequently, might not fully optimize its system. 

 A fourth criterion typically requires that the data cannot represent periods of frequent 

unequalized slug loading treatment upsets or shut-down periods1

 because these excursion data do 

not reflect performance that would be expected from well-designed and operated treatment 

systems. Furthermore, it would not be appropriate for the limitations to be based, in part, upon 

data reflecting extreme events that are beyond the control of the facility, because regulatory 

provisions at 40 CFR 122.41(n) would apply to such circumstances. More specifically, after the 

final limitations are incorporated into permits, EPA expects that when such events occur that the 

facility would abide by the procedural requirements in §122.41(n) to obtain an affirmative 

defense to any potential enforcement action. 

 In applying the fourth criterion, EPA evaluates the pollutant concentrations, flow values, 

mass loadings, plant logs, and other available information. As part of this evaluation, EPA 

 

1

 EPA applies this criterion to data from two types of shut-downs. First, treatment systems are sometimes halted to 

control upset conditions. As part of the recovery activities, the facility may pump out wastewater from the 

equipment (e.g., tanks) which contains highly concentrated wastes associated with the upset. Second, the facility 

may shut down its operations for maintenance and other atypical operations. During these periods, the facility may 

still operate its treatment system, but typically discharges effluent associated with atypical influent. For example, the 

influent might include cleaning solvents instead of process wastewater. 
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July 2009 14-4 

typically asks the facility about process or treatment conditions that may have resulted in 

extreme values (high and low). As a consequence of this review, EPA may identify certain time 

periods and other outliers in the data that reflect poor performance by an otherwise well-operated 

site. 

 The fourth criterion also is applied in EPA’s review of data corresponding to “start-up” 

periods. Most industries incur start-up conditions only during the adjustment period associated 

with installing new treatment systems. During this acclimation and optimization process, the 

concentration values tend to be highly variable with occasional extreme values (high and low). 

After this initial adjustment period, the systems should operate at steady state for years with 

relatively low variability around a long-term average. Because start-up conditions reflect onetime operating conditions, EPA generally excludes such data in developing the limitations. In 

contrast, EPA expects airports to encounter start-up operations at the start of every deicing 

season because they probably will cease treatment operations during warmer months. Because 

this adjustment period will occur every year for the Airport Deicing Category, EPA is proposing 

to include start-up data in the data set used as the basis of the limitations. However, through its 

application of the other three criteria, EPA would exclude extreme conditions that do not 

demonstrate the level of control possible with proper operation and control even during start-up 

periods. 

 In part, by retaining start-up data for limitations development, the limitations will be 

achievable because EPA based these limits on typical treatment during the entire season. Once 

the treatment system reaches steady state, EPA expects a typically well-designed and operated 

system to run continuously until the end of the deicing season. Conversely, EPA might determine 

that systems that operated only during relatively short periods, such as during each winter storm 

event (i.e., of only several days duration), might be poorly operated because the model 

technology requires more time to reach steady state. In other words, it would be ineffective and 

disruptive to turn the system on and off throughout the deicing season, particularly for biological 

systems, such as the model technology, and EPA may reject data if it determines that it reflects 

this type of operation. 

14.2.2 Other Considerations in Data Selection 

 In comments on proposed regulations across a range of industry categories and 

subcategories, industries often suggest that EPA consider additional criteria in selecting data as 

the basis of the limitations. Because EPA is aware of the issues behind these suggested criteria, it 

routinely considers whether they are relevant and should be considered as it develops new 

proposed regulations. As explained below, EPA also considered these criteria for the airport 

deicing rulemaking, but determined that they were not relevant in selecting data as the basis of 

the proposed limitations. EPA’s rationale is consistent with its findings for other industries. 

 Commenters often suggest a criterion related to the size of facilities because of concerns 

about a perceived impact of volume, or flow, of wastewater on treatment performance. In 

considering this issue for the airport deicing industry, EPA concluded that the size of the airport, 

deicing pads, and other features, by themselves, would not affect the performance of the 

treatment system. Instead, the airport size and water flow would determine the size of the 

treatment system, rather than its performance. EPA expects that each airport would build and 

operate a system that is sized appropriately for its volume of wastewater. Because the method of 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-5 

treatment is the same regardless of the flow, properly-sized systems should all perform in the 

same manner, and thus, achieve the same effluent concentrations. Before reaching this 

conclusion for airport deicing and other industries, EPA reviewed treatment technologies, such 

as biological treatment, oil-water separators, dissolved air floatation, and settling tanks. EPA's 

record supports the finding that for a variety of industrial sectors, well-operated and designed 

treatment systems treat different wastewaters with varying flows to a narrow range of effluent 

concentrations (EPA 2006). 

 In addition, commenters typically suggest a criterion that would require a minimum 

number of facilities be used as the basis of the limitations. Such suggestions are based upon two 

main concerns. First, commenters are concerned that the limitations do not reflect treatment from 

a range of typical influents, because the concentration levels vary from facility to facility. 

Second, commenters are concerned that not all facilities could achieve the same high level of 

performance from the model technology. For the first concern, as part of its evaluation of the 

effect of flow described above, EPA also considered the impact of influent pollutant 

concentrations. EPA found that well-operated and designed treatment systems are capable of 

treating the wastewaters to a narrow range of effluent pollutant concentrations. For the second 

concern, EPA only needs to demonstrate that the model technology can be operated at the level 

of performance on which the limitations are based. EPA’s selection of the model technology 

used at the Albany, New York airport as the basis of the limitations is appropriate because that 

facility demonstrates that the technology can achieve the levels reflected in the proposed 

limitations. 

 The Clean Water Act specifically authorizes EPA to base BAT/NSPS limitations and 

standards on the performance of a single facility. It is well established that BAT represents the 

best performance in the industrial category. Thus, it is not unusual for EPA to base effluent 

limitations on data from a single facility. For example, in the Organic Chemicals, Plastics and 

Synthetic Fibers (OCPSF) effluent guideline promulgated in 1987, EPA based 38 percent of the 

limitations on the performance of a single facility (EPA, 1987). Courts have recognized that EPA 

must act on the information it has, and need not wait for perfect information. See e.g., BASF 

Wyandotte Corp. v. Costle, 598 F.2d 637, 652-653 (1st Circuit, 1979.) 

14.2.3 Importance of Comments for Data Evaluations for Final Limitations 

 EPA has provided data in the proposed rulemaking record and explained the criteria used 

to review and evaluate this data. EPA encourages airport operators to submit comments about the 

proposed limitations in any case. For example, if an airport has concerns that the final rule may 

include more stringent limitations than those proposed, the airport may wish to provide 

comments and data that support the proposed limitations. 

 EPA will consider the comments and other information in performing its data review for 

the final rule. As a result of considering new information when applying the data selection 

criteria, EPA may reach new conclusions about whether certain proposal data should be included 

or excluded as the basis of the final limitations. It also is possible, as a consequence of new data, 

that EPA would revise its approach and/or calculate different values for the performance 

limitations and standards. As a consequence, the final limitations and standards could be more or 

less stringent than those proposed. 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-6 

14.3 Conventions for Modeling Multiple Data Sets from the Same Facility

 This section describes EPA’s conventions for modeling multiple data sets from the same 

facility. Data from a particular facility are sometimes collected at different times, from different 

treatment units, or by different organizations. In such cases where multiple data sets exist for the 

same facility, EPA often statistically models the data as if each data set represents a different 

facility. This section describes conventions applied to the data from the airport deicing industry. 

 EPA generally considers data from different time periods to characterize different 

operating conditions due to changes such as management, personnel, and procedures. Because 

EPA expects airports to operate treatment systems only for a limited time each year, it 

considered whether the conditions and performance for each deicing season tend to vary in a 

manner that more appropriately reflects different treatment systems. Because it may better 

capture the variability of airport deicing operations under a range of conditions, EPA has 

calculated the proposed limitations using all of the data, without regard to season. For 

informational purposes, the data and summaries are presented by season. 

 EPA generally uses data from separate treatment units (depending on the rulemaking, 

also called “trains” or “systems”) as if they characterized separate facilities. EPA has determined 

this is appropriate because the units were operated separately. Even if the wastes were generated 

by the same processes or drawn from the same storage pond, EPA considers that the performance 

of each system can vary due to slightly different influents, equipment, and other factors. 

 EPA generally considers data from different organizations to characterize different 

collection methods and analytical methods. The different organizations typically are EPA 

sampling teams and the facility’s monitoring crew at the treatment system. EPA often separates 

such data into multiple data sets, to better model the variability consistent with the use of a single 

analytical method and the same collection procedures. Consistent use of a single method and 

procedure is often required by permits and is typical of monitoring for compliance. Therefore 

this convention generally is used to model typical variability that each facility would experience 

in compliance monitoring activities. EPA then determines which, or all, multiple data sources are 

appropriate choices as the basis of the limitations. 

14.4 COD: Data Selected as Basis of Proposed Limitations

 In establishing the proposed limitations, EPA reviewed COD data from a treatment plant 

at the Albany International Airport, which used the model BAT. (Selection of the model 

technology is described in Section 13, and in the preamble to today’s rule.) EPA collected COD 

data during an EPA sampling episode at Albany Airport, and obtained several years of 

monitoring data and other information from Albany. After evaluating data from EPA’s sampling 

episode and the data and information supplied by Albany, EPA determined that the Albany data 

were the only available performance data from the model technology.2

 Thus, all other data sets 

were excluded by applying the third criteria in Section 14.2.1, because they did not demonstrate 

the performance of the model technology. The following sections describe the Albany airport 

 

2

 Akron Canton Airport in Ohio started operating the model technology in mid-November in 2007. When EPA was 

completing its technical analysis of the industry in late spring 2008, the airport’s treatment unit was not operating at 

full capacity. 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-7 

and apply the criteria in identifying the specific data points used as the basis of the proposed 

limitations. 

14.4.1 Albany Treatment System 

 EPA based the proposed limitations for COD upon data from Albany Airport’s treatment 

system. This system consists of two identical units that are consistent with EPA’s model 

technology described in Section 13. The airport diverts runoff from deicing operations into a 

lagoon. Personnel at the facility then pump water from the lagoon to one anaerobic unit or the 

other for treatment. The airport generally operates the two treatment systems in parallel, but 

sometimes runs them in series. At the end of each unit, regardless of whether the system is in 

parallel or series, the airport monitors COD concentrations each morning by collecting grab 

samples to evaluate the treatment performance. These locations are labeled as ArprtR-101 and 

ArprtR-102 in Figure 14-1. During its five-day sampling episode conducted from February 5th to 

9th in 2006, EPA measured COD and ammonia concentrations in composite samples collected at 

a point (labeled EPA_SP-2) where the two units combine into a single flow before entering an 

aerobic polishing pond for more treatment. After this step, the airport typically directly 

discharges waste into Shaker Creek, a tributary of the Mohawk River, which has been classified 

as a New York State Class A drinking water stream. As a consequence, the airport is required to 

meet stringent limitations when it discharges directly to the creek. In warmer weather (i.e., when 

the soil is 50 degrees or warmer), the airport sometimes uses the treated wastewater for 

irrigation. In addition, the airport has the capability of discharging to a POTW, although it 

seldom uses this discharge mechanism. 

 As the basis for the proposed limitations for COD, EPA selected the data at sample points 

ArprtR-101 and ArprtR-102 because each unit is the same as the model treatment system that 

EPA identified in Section 13. The airport has monitored their performance for a relatively long 

period of time, and provided EPA with data from December 1, 1999 through April 10, 2009 (ten 

deicing seasons). Because the influent was highly concentrated, it was not necessary to perform 

the long-term average test described in Section 14.2.3

 

 DCN AD01181 provides the influent and effluent COD data as originally submitted by 

the airport and the data are graphically displayed in the statistical support memo 

(DCN#AD01208). The following sections describe the exclusion of data collected from the EPA 

sampling episode and the airport’s self-monitoring data. 

 

3

 EPA typically compares average influent levels to a multiplier of 5 to 10 times the quantitation limit (or reporting 

limit). As explained in Section 14.1.1, the airport data had a lower measurement limit of 2.0 mg/L. Thus, in the longterm average test, EPA would probably have compared the influent data to a reference level of 10 to 20 mg/L. 

However, because the minimum influent value of 100 mg/L exceeded this range of potential reference values, the 

average values also will meet the requirements of the LTA test. 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

Lagoon 

Anaerobic unit #1 

Anaerobic unit #2 

Aerobic 

polish 

ArprtR-102 

(COD) 

AprtR-101 

(COD) 

EPA_SP-2 

(COD, Ammonia) 

Figure 14-1. Simplified Drawing of Albany Treatment System and Sample Points 

14.4.1.1 COD Data from EPA Sampling Episode at Albany 

 During EPA’s sampling episode, EPA and the airport collected separate sets of samples 

and their concentrations are provided in Table 14-1. At sample point EPA_SP-2, EPA collected 

samples of the combined flow from the two units. In contrast, the airport monitored the effluent 

directly from each unit at sample points ArptR-101 and ArptR-102. Both sets of samples 

demonstrate the performance of the model technology because no additional treatment steps exist 

between the airport sample points and EPA’s sample point. Rather than include data from two 

different sources (i.e., EPA and the airport) for the same dates, EPA preferentially selected the 

airport data because they were part of longer-term monitoring. Although the EPA data were 

therefore excluded as the basis of the limitations, EPA notes that all of the values are less than 

the value of 271 mg/L for the proposed daily maximum limitation. 

Table 14-1. COD: EPA and Airport Self-Monitoring Effluent Data Collected During EPA’s 

Sampling Episode 

COD Concentrations (mg/L) 

EPA Sampling Episode Data Airport Self-Monitoring Data 

Sample Date Original Sample 

Field Duplicate 

(where collected) AprtR-101 AprtR-102 

2/5/06 72 29 74 

2/6/06 228 208 53 108 

2/7/06 92 177 56 94 

2/8/06 81 31 90 

2/9/06 193 48 96 

July 2009 14-8 
Technical Development Document for Proposed Effluent 14. Limitation and Standards 

Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-9 

14.4.1.2 COD Self-Monitoring Data from Albany Airport 

 The airport typically runs the two units in parallel. When operated in this manner, EPA 

considers each unit’s performance to be consistent with the model technology. In its evaluation 

of the data from each unit, EPA applied the criteria and other considerations described in Section 

14.2. As a result of this evaluation, EPA excluded data associated with atypical operations, 

influent concentrations reported as zero, estimated values, and poor performance. The exclusions 

are described below. 

 By applying the third criterion in Section 14.2.1, EPA excluded all periods when the units 

were operated in series because the data did not reflect treatment by the model technology. Table 

14-2 identifies these time periods by deicing season (e.g., Season99 started in 1999 and 

continued into 2000). During these periods, one unit provided initial treatment and the second 

provided additional treatment. Although the facility reported effluent values from each unit 

during this period of operating in series, it only discharged the effluent from the second unit in 

the series. EPA considers the effluent data from the first unit to reflect less than optimal 

performance, because the operators presumably would have not optimized treatment because 

they intended to treat the wastes a second time (criterion 3). EPA considers the effluent data 

from the second unit to characterize treatment of atypical influent (i.e., effluent that had been 

treated by the first unit). 

Table 14-2. COD: Dates Excluded Because Units Operated in Series 

Season Number Days Excluded Beginning Date End Date 

Season99 32 2/9/2000 3/11/2000 

Season00 31 12/12/2000 1/11/2001 

Season01 3 2/7/2002 2/9/2002 

Season02 8 11/17/2002 11/24/2002 

3 4/5/2003 4/7/2003 

Season05 25 1/10/2006 2/3/2006 

Season06 79 1/15/2007 4/3/2007 

Season07 31 2/2/2008 3/3/2008 

 EPA excluded effluent values for both units when the influent concentration was reported 

as “zero” for two reasons. First, if COD could not be detected in the influent (criterion 2), then 

the effluent concentrations would not reflect any additional treatment. Second, it appears that the 

plant used this convention to indicate shut-downs of the system (criterion 4). Table 14-3 

identifies the dates when the influent concentration was reported to be zero. For the final rule, 

EPA also may exclude effluent values when the influent concentration was greater than zero, but 

the flow (or feed) rate was reported as zero, because these data also may indicate that the system 

was not operating. 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-10 

Table 14-3. COD: Dates Excluded Because Influent Concentration Reported as Zero 

Season Date 

Season01 6/14/2002

Season02 11/16/2002

Season06 4/10/2007

 EPA also excluded any data values that were estimates because they did not meet EPA’s 

definition for “data” described in Section 14.2. There were two types of estimated values. One 

type was indicated by italicized font in the facility’s spreadsheets as a convention to indicate that 

the operator’s log indicated issues with the sample or its analysis, and thus, the reported value 

was an estimate. The second type was a series of identical values reported over consecutive 

monitoring days. Although it is possible to find exactly the same pollutant concentrations on 

consecutive days, variations from day to day are more typical. In response to EPA’s questions 

about the strings of identical values, the facility stated that it sometimes carried down the last 

known number when they did not monitor. (DCN AD01206) To model the variability likely to 

be present in the effluent, EPA assumed that the first non-zero value was the only day when 

COD was monitored when three or more days had identical values for the same unit. In other 

words, EPA retained the value for the first day and deleted the (identical) values on subsequent 

days for that unit. If the values were zero, EPA assumed that the unit was not operating and 

excluded the entire time period, including the first reported zero value. The statistical support 

memo (DCN#AD01208) identifies these exclusions. 

 In addition, by applying the fourth criterion in Section 14.2, EPA excluded periods that 

did not reflect the typical performance of the technology. As shown in Table 14-4, these 

exclusions included treatment system upsets and method error. For example, EPA excluded the 

maximum value of 1283 mg/L recorded at ArprtR-101 on 3/21/2001 because it was inconsistent 

with the other data values during that time period. The plant management agrees that the value 

does not reflect normal operations, and suspects that it was likely a sample with high solids 

content. (DCN AD00825) 

Table 14-4. COD: Dates Excluded Because of Performance Excursions 

Season Number Days Excluded Beginning Date End Date Reason 

Season99 11 12/1/2000 12/11/2000 System Upset 

42 1/12/2001 2/22/2001 System Upset 

1 3/20/01 3/20/01 Method Error 

Season00 

1 3/21/01 3/21/01 System Upset 

After incorporating the exclusions, more than 2500 measurements of COD remained and were 

used as the basis of the proposed limitations. Table 14-5 summarizes the data. The statistical 

support memo (DCN AD01208) provides a listing and plots of the data. 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-11 

Table 14-5. COD: Summary of Albany Self-Monitoring Effluent Data After Exclusions 

COD Concentrations (mg/L) 1

Unit Season 

# of 

Days 

Standard 

Deviation Minimum Maximum Median Mean 2

Season99 147 50.31 1 326 14.0 28.60 

Season00 112 71.93 2 575 64.0 75.46 

Season01 168 20.97 9 157 37.0 44.02 

Season02 180 64.41 20 655 73.0 86.80 

Season03 146 103.19 2 699 50.0 76.32 

Season04 140 30.76 2 275 25.0 31.51 

Season05 90 18.08 8 162 29.5 31.56 

Season06 62 24.08 1 136 17.0 23.10 

Season07 124 98.07 9 1042 41.5 54.48 

Season08 120 59.85 15 674 35.0 42.74 

ArprtR_101 

ALL 1289 66.67 1 1042 37.0 52.28 

Season99 141 17.41 1 93 11.0 16.85 

Season00 117 51.50 11 393 55.0 63.09 

Season01 165 20.23 10 168 35.0 40.01 

Season02 183 51.73 25 685 51.0 57.61 

Season03 147 30.03 1 210 60.0 63.12 

Season04 145 73.96 2 725 76.0 87.42 

Season05 95 33.21 22 275 72.0 77.19 

Season06 62 41.68 2 148 46.5 61.34 

Season07 98 10.01 12 58 34.0 33.70 

Season08 120 24.92 12 282 37.0 39.07 

ArprtR_102 

ALL 1273 45.65 1 725 45.0 53.40 

1

 In this summary, non-detected values are set equal to the detection limit. 

2 The mean is calculated as the arithmetic average. 

14.5 Ammonia: Data Selected as Basis of Proposed Limitation

 For ammonia, EPA is proposing a compliance alternative with a daily maximum 

limitation for airports that use urea deicers on the runways. This section describes the data 

selected as the basis of the proposed limitation for ammonia. 

 After evaluating the available data, EPA transferred the ammonia data from the anaerobic 

fluidized bed technology which is the model technology for COD. This transfer was necessary 

because an AFB system by design creates ammonia as a by-product of wastewater treatment. 

Consequently, AFB discharges could have higher ammonia concentrations than typically found 

in airfield runoff when urea is not present. If the treated aircraft discharges then were discharged 

to the same pipe as the runway runoff, the airport might have difficulties complying with the 

ammonia limitation. EPA also confirmed that ADF treatment provided less concentrated 

discharges than observed from the application of urea products (see DCN AD01194). For these 

reasons, EPA determined that it was appropriate to use the ADF data as a basis of limitations that 

would apply to runway runoff. 
Technical Development Document for Proposed Effluent 14. Limitation and Standards 

Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-12 

 As it had for COD, EPA initially evaluated the Albany data for setting proposed 

limitations for ammonia, because EPA had data on the performance of its model technology. In 

contrast to its practice of monitoring COD at the end of each treatment unit, the airport 

monitored ammonia at its permit compliance point after additional treatment provided by an 

aerobic polishing step. The anaerobic polishing step would result in decreased ammonia 

concentrations and would not represent ammonia discharges from use of urea on airfields. Thus, 

to propose an effluent limit consistent with the model technology EPA used the EPA data and 

excluded the Albany ammonia data (criterion 3). 

 Instead, because they reflect the capability of the model treatment system, EPA used its 

sampling data from EPA_SP-2, shown in Table 14-6, as the basis of the proposed ammonia 

limitations. (Section 14.6 describes field duplicates and the importance of daily values for the 

limitation calculations.) In analyzing samples from this episode, the laboratory achieved a 

detection limit of 0.05 mg/L. During the laboratory’s quality assurance step of the chemical 

analysis, it detected ammonia in the laboratory preparation blank at a concentration of 0.069 

mg/L. Other quality assurance parameters, initial calibration blanks and continuing calibration 

blanks, were between 0.052 mg/L and 0.054 mg/L. The ammonia results for all samples are 

greater than ten times the blank result, with the exception of four influent and one source water 

samples that were not used as the basis of the proposed limitation. As a consequence, EPA 

determined that the data were of acceptable quality to use as the basis of the proposed 

limitations. 

Table 14-6. Ammonia: Data from Albany Airport Used to Develop Limitations 

Ammonia Concentrations (mg/L) 

Effluent 

Sample Day Influent Original Sample 

Field Duplicate 

(where collected) 

Daily Value Used in 

Limitations Calculations 

1 ND (0.1) 2.58 2.58 

2 ND (0.1) 4.14 3.95 4.05 

3 ND (0.1) 4.45 5.54 5.00 

4 ND (0.1) 6.12 6.12 

5 0.91 6.65 6.65 

14.6 Limitations: Basis and Calculations

 The proposed limitations, as presented in today's notice, are provided as the daily 

maximum limitation for COD and ammonia. In addition, the notice includes a weekly average 

limitation for COD. This section defines the limitations (Section 14.6.1); describes the statistical 

percentile basis of the limitations (Section 14.6.2); and the estimation of the percentiles for COD 

and ammonia (Sections 14.6.3). The statistical support memo (DCN AD01208) describes the 

calculations used to model the ammonia data, as well as additional statistical models that EPA 

may consider in developing the final limitations. 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-13 

14.6.1 Definitions 

 Definitions provided in 40 CFR 122.2 describe the limitations in terms of “daily 

discharge” which it defines 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.” As a 

consequence, EPA generally arithmetically averages all measurements recorded for each 

uniquely reported time period (e.g., 12/21/2004) before calculating limitations. EPA refers to this 

averaged value as the “daily value.” 

 First, in calculating the limitations, EPA ensures that it has only one value for each day. 

Field duplicates are one example of multiple measurements, and were included in the ammonia 

data used to develop the proposed limitations. Field duplicates are two samples collected for the 

same sample point at approximately the same time, flagged as duplicates for a single sample 

point, and measured separately. Because the analytical data from each duplicate pair characterize 

the same conditions at that time at a single sample point, EPA typically averages the data to 

obtain one data value for those conditions on that day. For example, Table 14-7 shows the field 

duplicates and daily, averaged, values for ammonia. 

 Second, EPA uses the daily values in calculating the limitations. Definitions provided in 

40 CFR 122.2 further describe the “maximum daily discharge limitation” as the “highest 

allowable ‘daily discharge.’” The “average weekly discharge limitation” is the “highest 

allowable average of ‘daily discharges’ over a calendar week, calculated as the sum of all ‘daily 

discharges’ measured during a calendar week divided by the number of ‘daily discharges’ 

measured during that week.” 

 Although EPA has not proposed a monthly average limitation, the following sections will 

describe EPA’s deliberations and evaluations of the monthly average limitation. The maximum 

for monthly average limitation (also referred to as the “average monthly discharge limitation” 

and “monthly average limitation”) is the “highest allowable average of ‘daily discharges’ over a 

calendar month, calculated as the sum of all ‘daily discharges’ measured during a calendar 

month divided by the number of ‘daily discharges’ measured during that month.” 

14.6.2 Percentile Basis of the Limitations 

 EPA uses a statistical framework to establish limitations that facilities are capable of 

complying with at all times. Statistical methods are appropriate for dealing with effluent data 

because the quality of effluent, even in well-operated systems, is subject to a certain amount of 

fluctuation or uncertainty. Statistics is the science of dealing with uncertainty in a logical and 

consistent manner. Statistical methods together with engineering analysis of operating 

conditions, therefore, 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. 

Using statistical methods, EPA has derived numerical values for its proposed daily maximum 

limitations and weekly average limitations. 

 The statistical percentiles are intended, on one hand, to be high enough to accommodate 

reasonably anticipated variability within control of the facility. The limitations also reflect a level 

of performance consistent with the CWA requirement that these limitations be based on the best 

technologies that are properly operated and maintained. 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-14 

 In establishing daily maximum limitations, EPA’s objective is to restrict the discharges 

on a daily basis at a level that is achievable for an airport that targets its treatment system design 

and operation at the long-term average while allowing for the variability around the long-term 

average that results from normal operations. This variability means that at certain times airports 

may discharge at a level that is greater than the long-term average. This variability also means 

that airports may at other times discharge at a level that is considerably lower than the long-term 

average. To allow for possibly higher daily discharges, EPA has established the daily maximum 

limitation at a relatively high level (i.e., the 99th percentile). Due to routine variability in treated 

effluent, an airport that discharges consistently at a level near the daily maximum limitation, 

instead of the long-term average, may experience frequent values exceeding the limitations. For 

this reason, EPA recommends that airports target the treatment system at the long-term average 

that it derived for the model technology. 

 In its derivation of the weekly average limitation for COD, EPA used an estimate of the 

97th percentile of the weekly averages of the daily measurements. This percentile basis is the 

midpoint of the percentiles used for the daily maximum limitation (i.e., 99th percentile of the 

distribution of daily values) and the monthly average limitation (i.e., 95th percentile of the 

distribution of monthly average values). Courts have upheld EPA’s use of these percentiles, and 

the selection of the 97th percentile is a logical extension of this practice. Compliance with the 

daily maximum limitation is determined by a single daily value; therefore, EPA considers the 

99th percentile to provide a reasonable basis for the daily maximum limitation by providing an 

allowance for an occasional extreme discharge. Because compliance with the monthly average 

limitation is based upon more than one daily measurement and averages are less variable than 

daily discharges, EPA has determined that facilities should be capable of controlling the average 

of daily discharges to avoid extreme monthly averages above the 95th percentile. In a similar 

manner to the monthly average limitation, compliance with the weekly average limitation also 

would be based upon more than one daily measurement. However, the airport would monitor for 

a shorter time and thus would have fewer opportunities to counterbalance highly concentrated 

daily discharges with lower ones. For this reason, EPA is proposing a larger percentile for the 

weekly average limitation than the one used for the monthly average limitation. Consequently, 

EPA is proposing the 97th percentile as an appropriate basis for limiting average discharges on a 

weekly basis. EPA also considers this level of control in avoiding extreme weekly average 

discharges to be possible for airports using the model technology. 

14.6.3 Estimation Procedures for Percentiles 

 This section describes the estimation procedures that EPA used to calculate the 

limitations considered for the proposed rulemaking. Table 14-7 provides a summary of the 

limitations that EPA proposes for COD and ammonia. Sections 14.6.3.1, 14.6.3.2, and 14.6.3.3 

describe the estimation procedures used to model the COD data and the June 8, 2009 

memorandum on calculation of percentiles (DCN AD01213) describes the calculations used by 

the statistical software. Section 14.6.3.4 describes the procedures for ammonia. Also, as 

described in Section 14.6.4.3 and 14.6.3.4, EPA considered a weekly average limitation for 

ammonia and monthly average limitations for both pollutants. 
Technical Development Document for Proposed Effluent 14. Limitation and Standards 

Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-15 

Table 14-7. COD and Ammonia: Proposed Limitations with Long-Term Averages and 

Variability Factors 

Parameter Time Period COD Ammonia 

Limitations (mg/L) Daily Maximum 271 14.7 

Weekly Average 154 N/A 

Long-Term Average (mg/L) All 41.0 5.24 

Variability Factors Daily 6.61 2.81 

Weekly 3.8 N/A 

14.6.3.1 COD: Daily Maximum Limitation and the 99th Percentile 

 For COD, EPA based the proposed daily maximum limitation on an estimate of the 99th

percentile of the distribution of the daily values. This section describes the percentile estimates 

and the long-term average. 

 First, EPA used nonparametric methods to estimate the 99th percentile of the daily values 

from each unit. A simple nonparametric estimate of the 99th percentile of an effluent 

concentration data set is the observed value that exceeds 99 percent of the observed data points. 

Because EPA had more than 1200 data points for each unit, it determined that the empirical 

approach would provide reasonable estimates of the 99th percentiles. 

 Second, EPA set the proposed limitation equal to the median of the two 99th percentile 

estimates, or 271 mg/L. The median is, by definition, the midpoint of all available data values 

ordered (i.e., ranked) from smallest to largest. As result, half of the unit 99th percentiles are 

higher than the median, and half are lower. (In this particular case, because there are two units, 

the median is equal to the arithmetic average (or mean).) 

 Table 14-8 summarizes the percentile estimates for the two units, the minimum and 

maximum values observed in the data, and the 50th percentiles. Because of the importance of 

targeting treatment to the long-term average, EPA recommends that facilities design, maintain, 

and operate the treatment system to achieve a long-term average of 41 mg/L which is the median 

of the 50th percentiles, of 37 and 45 mg/L, from the two units. The allowance for variability, or 

the ratio of the limitation to the long-term average, is 6.6. (EPA usually refers to this allowance 

as the “variability factor.”) In other words, the daily maximum limitation is 6.6 times greater 

than the long-term average achievable by the model technology. By targeting the system to the 

long-term average and controlling its variability within this range, the facility will be capable of 

complying with the limitation. 

Table 14-8. COD: 99th Percentile Estimates from Each Treatment Unit 

Concentrations (mg/L) 

Treatment Unit 

Number of Daily 

Values Minimum 50th Percentile Maximum P99 

ArprtR-101 1289 1 37 1042 326 

ArprtR-102 1273 1 45 725 216 

Median Values 41 271 
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Limitation Guidelines and Standards for the Airport Deicing Category Data Selection and Calculation 

July 2009 14-16 

14.6.3.2 COD: Weekly Average Limitation and the 97th Percentile 

 For the weekly average limitation of COD, EPA first calculated, for each unit, the 

arithmetic average of the measurements observed during each week, excluding weekends (to be 

consistent with the assumed monitoring costs, although permit authorities may specify different 

monitoring requirements). EPA then used the nonparametric method to derive a 97th percentile of 

the more than 200 weekly averages for each unit, and set the proposed limitation equal to the 

median of the two 97th percentile estimates, or 154 mg/L. The statistical support memo (DCN 

AD01208) lists the weekly averages. 

 Because data was not always available for every weekday during a week, EPA examined 

whether the weekly averages were affected by the number of weekdays included in the average. 

As shown in Table 14-9, the value of the limitation varied only slightly if the weeks were 

required to have data for all five days. The June 23, 2009 memorandum on percentiles for 

weekly averages (DCN AD01214) provides a more detailed evaluation. 

Table 14-9. COD: Effect of Number of Daily Values in Weekly Averages 

Unit ArprtR-101 Unit AirprtR-102 

Number of Daily 

Values in Average 

Number of 

Weekly 

Averages 

97th 

Percentile 

Number of 

Weekly 

Averages 

97th 

Percentile 

Median of 97th 

Percentiles 

5 155 176.8 157 133.6 155.2 

4 or 5 181 176.8 181 133.6 155.2 

1 to 5 1 209 162.4 203 145.5 153.95 

1 Averages in this row were used as the basis of the proposed weekly average limitation. 

14.6.3.3 COD: Monthly Average Limitation and the 95th Percentile (NOT 

Proposed) 

 For COD, EPA is proposing and soliciting comment on use of a weekly average instead 

of a monthly average limitation because it appears to be a better fit for this industry from a 

monitoring perspective. However, two factors may warrant another approach in the final rule. 

First, a week may be too short a period to ensure that airports will optimize their systems 

appropriately over a longer period to achieve the long-term average. Second, the industry and 

permit writers may prefer other alternatives. Another approach may include the monthly average 

limitation. For comparison purposes, EPA tentatively estimated 112 mg/L as the 95th percentile 

of the monthly averages using a statistical model based upon the lognormal distribution. The July 

20, 2009 memorandum on the COD monthly average limitation (DCN AD01212) describes these 

calculations. If EPA were to establish a monthly average limitation, it would examine the 

statistical properties of the data to determine the appropriate model and statistical assumptions. 

The August 2009 memorandum on time series modeling of effluent data (DCN AD01209) 

describes this evaluation for several years of the monitoring data. 

14.6.3.4 Ammonia: Percentile Estimates Based Upon the Lognormal Distribution 

 Because the ammonia data set had fewer than 100 observations, EPA used a parametric 

approach to model the data. If a data set consists of fewer than 100 observations the best that can 
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be done, using nonparametric methods, is to use the maximum value as an approximate 

nonparametric estimate of the 99th percentile, but this can underestimate the true value. 

Parametric methods require that a probability distribution be specified and this allows estimation 

of unknown parameters from the available data. The estimated parameters are a function of the 

defined distribution and the data, and thus the parametric method enables the percentiles of 

effluent concentrations to be computed analytically. EPA’s selection of parametric methods in 

developing limitations for other industries is well documented (e.g., Iron and Steel; Pulp, Paper 

and Paperboard; Metal Products and Machinery categories). EPA considers the lognormal 

distribution to be appropriate for the ammonia data, and this section describes its application in 

estimating the proposed daily maximum limitation. The daily maximum limitation of 14.7 mg/L 

is based upon an estimate of the 99th percentile of the lognormal distribution of the daily values. 

 The calculations include an adjustment for possible bias due to statistical autocorrelation. 

The adjusted variance then better reflects the underlying variability that would be present if the 

data were collected over a longer period. When data are said to be positively autocorrelated, it 

means that measurements taken at specific time intervals (such as 1 day or 2 days apart) are 

related. For example, positive autocorrelation would be present in the data if the final effluent 

concentration was relatively high one day and was likely to remain at similar high values the 

next and possibly succeeding days. EPA sampling data, used as the basis of the limitations, were 

collected on five consecutive days, and thus, the data may be autocorrelated, but the length of 

time was not sufficient for autocorrelation evaluations. Albany Airport’s self-monitoring data 

also were not suitable for the evaluation because they were collected at three-week intervals 

rather than consecutive days. In contrast, the Iron and Steel (I&S) rule had 244 data points for 

ammonia that generally were collected on consecutive days, so it was possible to evaluate 

autocorrelation in the data. Because the model technologies for both industries are biological 

systems, EPA concludes that the I&S autocorrelation adjustment is a reasonable transfer that can 

be used to calculate the airport deicing limitations.4

 Table 14-10 summarizes the proposed longterm average and daily maximum limitation, with and without the adjustment for autocorrelation. 

The proposed daily maximum limitation of 14.7 mg/L is 2.8 times greater than the long-term 

average, of 5.24 mg/L, achievable by the model technology. By targeting the system to the longterm average and controlling its variability within this range, the facility will be capable of 

complying with the limitation. However, ammonia is generated as a by-product of the model 

technology, and EPA expects the concentrations of ammonia to have similar variability to what 

is being treated (i.e., COD). In contrast to the COD limitations, which are based on a mixture of 

start-up and steady state periods, the ammonia limitation is based upon data collected only 

during steady state operations. In the preamble to the proposed rulemaking, EPA requests 

additional data that reflect ammonia discharges during start-up operations. 

 

4

 EPA has not incorporated a similar adjustment for autocorrelation into the data for the COD limitations because 

the limitation is based upon more than 2500 measurements collected over 10 years, which presumably would show a 

full range of variability expected by the model technology. (DCNs AD01210 and AD01214) 
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Table 14-10. Ammonia: Consideration of Autocorrelation for Proposed Limitations, LongTerm Averages, and Variability Factors 

Adjusted for Autocorrelation? 

Statistical Parameter No Yes (Proposed) 

Percent 

Difference 

Long-Term Average (mg/L) 4.97 5.24 5% 

Variability Factor 2.25 2.81 25% 

Daily Maximum Limitation (mg/L) 11.2 14.7 31% 

 Unlike COD, EPA is not proposing a weekly ammonia effluent limitation. The 

technology basis for the COD effluent limitations would operate throughout the deicing season 

with continuous discharges allowing for weekly monitoring. In contrast, urea is applied to 

airfield pavement as needed, and discharges would occur for a short time after the initial 

application, as the urea works its way through the stormwater collection and any associated 

treatment system that may be present. Most airports would have non-continuous and somewhat 

infrequent urea discharges. Consequently, it would be difficult to assume a single value for the 

monitoring frequency that could reasonably be applied to all airports, regardless of climatic 

conditions. In developing the average limitations, this assumed monitoring frequency is used in 

the statistical calculations. After reviewing any supplementary information and comments on 

EPA’s proposed limits, EPA may reevaluate whether weekly and/or monthly average limitations 

are necessary for proper control of ammonia. After modeling the data using the lognormal 

distribution as shown in the statistical support memo (DCN AD01208), EPA estimated values of 

9.75 and 6.98 mg/L for the weekly average limitation and monthly average limitation. 

14.6.3.5 Significant Digits for Proposed Limitations 

 In presenting the values of the proposed limitations, EPA rounded the values to three 

significant digits. EPA used a rounding procedure where values of five and above are rounded up 

and values of four and below are rounded down. For example, a value of 5.235 would be 

rounded to 5.24, while a value of 5.234 would be rounded to 5.23. 

14.7 Achievability of Limitations

 EPA promulgates limitations that sites are capable of complying with at all times by 

properly operating and maintaining their processes and treatment technologies. As a consequence 

of using the percentile basis for each proposed limitation, treatment systems that are designed 

and operated to achieve long-term average levels should be capable of compliance with the 

limitations, which incorporate variability, at all times. As verification that the limitations are 

achievable, EPA performs additional statistical and engineering reviews, as described in Section 

14.7.1. As a result of these reviews, EPA has concluded that these limitations are achievable, and 

thus, EPA expects facilities to comply with the limitations as explained in Section 14.7.2. 

14.7.1 Statistical and Engineering Review of 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 

control technologies and the airport conditions. The following sections describe two types of 
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comparisons. First, EPA compares the proposed limitations to the data used to develop the 

limitations. Second, EPA compares the limitations to the influent data. 

14.7.1.1 Comparison to Data Used As Basis for the Limitations 

 As part of its data evaluations, EPA compared the value of the proposed limitations to the 

values used to calculate the limitations. None of the data selected for ammonia were greater than 

its proposed daily maximum limitation which supports the engineering and statistical 

conclusions that the limitation values are appropriate. Because of the statistical methodology 

used for the COD limitations some values were greater than the proposed limitations. 

 For the COD, appropriately one percent of the values were greater than the proposed 

daily maximum limitation, which is consistent with the statistical basis (i.e., use of the 99th

percentile) of the limitation. Table 14-11 lists the data from both units and the influent, when 

one, or both effluent values were greater than the limitation. Of the 27 values greater than the 

proposed limitation, 20 were from the ArprtR-101 unit, and 7 from ArprtR-102 unit. Both units 

had values greater than the proposed limitation on three dates: 3/31/2001, 1/4/2005, and 

12/25/2008. For the final rule, EPA may contact Albany Airport to better understand these 27 

values, determine whether they should be considered upsets of the treatment units, and evaluate 

controls that will protect against these more concentrated discharges. 
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Table 14-11. COD: Dates and Values Greater than Proposed Limitation of 271 mg/L 

COD Concentrations (mg/L) 1

Season Date Influent ArprtR_101 ArprtR_102 

16MAR2000 6,170 326 33 Season99 

23MAR2000 6,560 315 93 

01MAR2001 6,240 276 232 

11MAR2001 5,430 288 64 

12MAR2001 6,520 575 92 

22MAR2001 6,040 129 393 

Season00 

31MAR2001 5,460 357 288 

18MAY2003 5,870 (Estimated to be 800) 685 

19MAY2003 6,020 460 95 

20MAY2003 5,920 655 86 

Season02 

22MAY2003 6,645 290 101 

20DEC2003 2,955 278 0 

03JAN2004 4,885 690 36 

08JAN2004 7,085 387 37 

08FEB2004 6,770 435 74 

09FEB2004 6,980 453 49 

16MAR2004 8,280 316 124 

Season03 

17MAR2004 8,300 699 118 

04JAN2005 8,670 275 725 Season04 

04FEB2005 5,845 38 360 

Season05 09DEC2005 1,100 162 275 

09JAN2008 8,630 1,042 Out of service Season07 

10JAN2008 8,630 433 Out of service 

Season08 25DEC2008 6,280 674 282 

1

 Bold text indicates effluent values greater than the limitations. 

 Of the 460 weekly averages of the COD concentrations, 14 averages had values that were 

greater than the proposed weekly average limitation of 154 mg/L. Of those 14 averages, 11 were 

during weeks when the unit also had one or more daily values that were greater than the daily 

maximum limitation. The statistical support memo (DCN AD01208) identifies the weeks and the 

corresponding daily values. 

14.7.1.2 Comparison to Influent 

 In addition to evaluating the data used as the basis of the limitations, EPA often compares 

the value of the proposed limitations to influent concentration levels. In these comparisons, EPA 

determines if the limitations perform as expected. 

 As part of its evaluation to determine if the COD limitation was sufficiently stringent to 

require that the influent be treated, EPA evaluated the COD influent discharges from Albany 

Airport. As shown in the summary statistics in Table 14-12, all influent values were greater than 

the proposed limitation during seven deicing seasons. For the other three seasons, only three 
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values (11/30/2005, 1/1/2007, and 1/2/2007) were less than the proposed limitation.5 This 

finding confirmed that the proposed limitation can only be met through treatment. 

Table 14-12. COD: Summary Statistics of Influent Concentrations 

COD: Influent Concentration (mg/L) 

Season #of Days 

Standard 

Deviation Minimum Maximum Median 

Arithmetic 

Average 

Season99 149 1,571 1,000 6,560 2,703 3,138 

Season00 117 1,254 1,797 7,950 5,505 5,204 

Season01 169 1,511 342 7,105 3,975 3,949 

Season02 183 1,807 2,915 10,470 7,260 7,107 

Season03 147 2,437 655 10,060 6,460 5,951 

Season04 145 1,777 1,848 8,870 5,430 5,243 

Season05 98 1,768 100 7,410 4,475 4,166 

Season06 64 1,677 100 5,760 1,903 2,567 

Season07 128 2,150 485 10,000 7,525 6,684 

Season08 120 4,409 3,550 18,300 8,875 10,022 

ALL 1,320 2,933 100 18,300 5,400 5,538 

14.7.2 Compliance with Limitations 

 EPA promulgates limitations that sites are capable of complying with at all times by 

properly operating and maintaining their processes and treatment technologies. However, the 

issue of exceedances or excursions (values that exceed the limitations) is often raised. In other 

rules, including EPA’s final OCPSF rule, commenters suggested that EPA include a provision 

that a facility is in compliance with permit limitations provided its discharge does not exceed the 

specified limitations, with the exception that the discharge may exceed the daily maximum 

limitation 1 day out of 100. EPA’s general approach in that case for developing limitations based 

on percentiles was the same as 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 the following: 

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. 

 This issue also was raised in EPA’s Phase I rule for the Pulp, Paper and Paperboard 

Category (EPA 1998). In that rulemaking, EPA used the same general percentile approach for 

 

5

 For all three dates, the facility reported the same values for influent (100 mg/L) and ArprtR-101 (30 mg/L). The 

facility reported a value of 30 mg/L for ArprtR-102 on the first date, and estimated values of 30 mg/L for the two 

dates in 2007. 
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developing monthly average limitations that it used for daily maximum limitation for the 

proposed airport deicing rule. The percentile approach for the monthly average limitation was 

upheld in National Wildlife Federation et al. v. Environmental Protection Agency, 286 F.3d 554, 

573 (D.C. Cir. 2002). The Court determined that: 

EPA’s approach to developing monthly limitations was reasonable. It established 

limitations based on percentiles achieved by facilities using well-operated and 

controlled processes and treatment systems. It is therefore reasonable for EPA to 

conclude that measurements above the limitations are due to either upset 

conditions or deficiencies in process and treatment system maintenance and 

operation. EPA has included an affirmative defense that is available to mills that 

exceed limitations due to an unforeseen event. EPA reasonably concluded that 

other exceedances would be the result of design or operational deficiencies. EPA 

rejected Industry Petitioners’ claim that facilities are expected to operate 

processes and treatment systems so as to violate the limitations at some pre-set 

rate. EPA explained that the statistical methodology was used as a framework to 

establish the limitations based on percentiles. These limitations were never 

intended to have the rigid probabilistic interpretation that Industry Petitioners 

have adopted. Therefore, we reject Industry Petitioners’ challenge to the effluent 

limitations. 

 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, for example, Rep. No. 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). 

 More recently, for EPA’s rule for the iron and steel industry, EPA’s selection of 

percentiles was upheld in American Coke and Coal Chemicals Institute v. Environmental 

Protection Agency, 452 F.3d 930, 945 (D.C. Cir. 2006). The Court determined that: 

The court will not second-guess EPA’s expertise with regard to what the 

maximum effluent limits represent. See Nat’l Wildlife, 286 F.3d at 571-73. As 

EPA explains in the Final Development Document, the daily and monthly average 

effluent limitations are not promulgated with the expectation that a plant will 

operate with an eye toward barely achieving the limitations. Final Development 

Document at § 14.6.2. Should a plant do so, it could be expected to exceed these 

limits frequently because of the foreseeable variation in treatment effectiveness. 

Rather, the effluent limitations are promulgated with the expectation that plants 

will be operated with an eye towards achieving the equivalent of the LTA for the 

BAT-1 model technology. Id. However, even operated with the goal of achieving 

the BAT-1 LTA, a plant’s actual results will vary. EPA’s maximum daily 

limitations are designed to be forgiving enough to cover the operations of a welloperated model facility 99% of the time, while its maximum monthly average 

limitations are designed to be forgiving enough to accommodate the operations of 
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July 2009 14-23 

a well-operated model facility 95% of the time. See id. EPA’s choice of percentile 

distribution represented by its maximum effluent limitation under the CWA 

represents an expert policy judgment that is not arbitrary or capricious. 

 EPA expects that airports will comply with promulgated limitations at all times. If the 

exceedance is caused by an upset condition, the airport 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, EPA has determined that the airport’s performance does 

not represent the appropriate level of control (best available technology for existing sources; best 

available demonstrated technology for new sources). 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 backup systems, and operator training and performance evaluations. 

14.8 References

EPA. 1987. Organic Chemicals and Plastics and Synthetic Fibers Category Effluent Limitations 

Guidelines, Pretreatment Standards and New Source Performance Standards; Final Rule. 40 

CFR Part 414, 52 FR 42522, November 5, 1987. 

EPA. 1998. National Emission Standards for Hazardous Air Pollutants for Source Category: 

Pulp and Paper Production; Effluent Limitations Guidelines, Pretreatment Standards, and New 

Source Performance Standards: Pulp, Paper, and Paperboard Category; Final Rule. 40 CFR 

Part 430, 63 FR 18503, April 15, 1998. 

EPA. 2002. Development Document for Effluent Limitations Guidelines and Standards for the 

Iron and Steel Manufacturing Point Source Category. EPA-821-R-02-004. Section 14.1. 

www.epa.gov/guide/ironsteel/ 

EPA. 2006. Notice of Availability of Final 2006 Effluent Guidelines Program Plan. 

December 21, 2006; 71 FR 76655