EPA 440/1-76/084 ' DRAFT 

Supplement For 

PRETREATMENT 

to the 

Development Document 

for the 

STEAM ELECTRIC 

POWER GENERATING 

Point Source Category 

U.S. ENVIRONMENTAL PROTECTION AGENCY 

NOVEMBER 1976 
SUPPLEMENT FOR PRETREATMENT 

TO THE DEVELOPMENT DOCUMENT 

FOR THE 

STEAM ELECTRIC POWER GENERATING 

POINT SOURCE CATEGORY 

Russell E. Train 

Administrator 

Andrew W. Breidenbach, Ph.D. 

Assistant Administrator 

for Water and Hazardous Materials 

Eckardt C. Beck 

Deputy Assistant Administrator for 

Water Planning and Standards 

Robert B. Schaffer 

Director, Effluent Guidelines Division 

John Lum 

Project Officer 

NOVEMBER 1976 

Effluent Guidelines Division 

Office of Water and Hazardous Materials 

U.S. Environmental Protection Agency 

Washington, D.C. 20460 
ABSTRACT 

This document presents the findings to date of an extensive 

study of that section of the Steam Electric Power Generating 

Industry which discharges industrial wastes to publicly 

owned treatment works (POTW). Its purpose is to develop 

pretreatment standards to implement section 307(b) of the 

Federal Water Pol 1 ution Control Act. 

Pretreatment standards, recommended in Section I1 of this 

report set forth the degree of effluent reduction achievable 

through the application of control technology currently 

available. These pretreatment standards set forth the 

degree of effluent reduction achievable through application 

of the available demonstrated control t'echnology, processes, 

operating methods, or other alternatives. These standards 

must be achieved no later than three (3) years from the 

date of promulgation. 

Supporting data and rationale for development of pretreatment standards are contained in this report. 
TABLE OF CONTENTS 

Page 

ABSTRACT 

NOTICE 

TABLE OF CONTENTS iii 

LIST OF FIGURES vii 

LIST OF TABLES 

I. CONCLUSIONS 

11. RECOMMENDATIONS 

I I I. INTRODUCTION 

General Background 

Purpose and Authority 

Scope of Work and Technical Approach 

General Description of the Industry 

Process Description 

Publicly-Owned Treatment Works (POTW) 

IV. INDUSTRY CATEGORIZATION 

Introduction 

Industry Categorization 

Factors Considered 

Age 

Size 

Fuel 

Geography 

Mode of Operation 

Raw Water Quality 

Volume of Water Used 

Pretreatment Technology 

iii 
TABLE OF CONTENTS (CONTINUED) 

Page 

V. WATER USE AND WASTE CHARACTERIZATION V-1 

Introduction V-1 

Principles of Operation of Steam Electric 

Power Plant V-1 

Water Use and Waste Characterization by 

Category V-6 

Condenser Cooling Water V-6 

Water Treatment V-23 

Demineral izer 

Boi 1 er Bl owdown 

Maintenance Cleaning 

Ash Handling Systems V-46 

Air Pollution Control Equipment V - 55 

The POTW Process V-60 

Effects of Steam-Electric Wastewaters 

On POTWs V-67 

VI. SELECTION OF POLLUTANT PARAMETERS VI-1 

Introduction VI-1 

Rationale for the Selection of 

Pollutant Parameters 

Properties of Selected Pollutant 

Parameters VI-2 

Pol 1 utants Rejected VI-17 
TABLE OF CONTENTS (CONTINUED) 

VII. TREATMENT AND CONTROL TECHNOLOGY 

Introduction 

End-of-Pipe Treatment Technology 

Treatment of Major Pollutants 

End-of-Pipe Technology for Major 

Waste Streams 

Water Management 

In-Plant Control Techniques 

Material Substitution 

Water Conservation and Wastewater Reuse 

VIII. COST, ENERGY AND OTHER NON WATER QUALITY 

ASPECTS 

IX. 

X. 

XI 

XI1 

Introduction 

Cost Reference and Rationale 

Costs for Pretreatment 

Levels of Pretreatment 

Cost Estimates 

~l timate Disposal 

Energy Considerations 

PRETREATMENT STANDARDS 

ACKNOWLEDGEMENTS 

REFERENCES 

GLOSSARY 

Page 

vii-1 
TABLE OF CONTENTS (CONTINUED) 

Page 

APPENDIX A - STATISTICAL ANALYSIS OF HISTORICAL A-1 

DATA 

APPENDIX B - WATER GLOSSARY B-1 

APPENDIX c - EFFECT OF POLLUTANT PARAMETERSON 

TREATMENT WORKS C-1 
LIST OF FIGURES 

Page 

111-9 

111-10 

111-11 

111-12 

Principal Fuel Use by Number 

Principal Fuel Use by Megawatts 

Year of Construction by Number 

Year of Construction by Megawatt 

Process Flow Diagram Steam Electric 

Power Industry 

Wastewater Treatment Sequence 

Typical Boiler for Oil-Fired Furnace 

Single-pass Condenser 

Fossil-Fueled Steam Electric Power 

Plant - Typical Flow Diagram 

Once-Through and Recirculating 

Cool ing Systems 

Diagram of Wet Forced - Air Cooling 

Tower 

Natural Draft Wet Cooling Tower 

(Counter Flow) 

Normal Distribution Diagram For 

Normalized Once-Through Usage Data 

Once-Through Cooling Water Use vs. 

Annual Production Rate 

Normal Distribution Diagram for 

Normalized Cooling Water Usage Data 

Recirculating Cooling Water Use vs. 

Annual Production Rate 

Commonly Used Water Treatment Methods 

vii 
LIST OF FIGURES (CONTINUED) 

Page 

V-28 

Normal Distribution Diagram for 

Normalized Boiler Makeup Water Usage 

Data 

Boiler Makeup Water Use vs. Annual 

Production Rate 

Normal Distribution Diagram for 

Normalized Ion Exchange Water Usage 

Data 

Demineralizer Water Usage vs. Annual 

Production Rate 

Flow Diagram for Recirculating Bottom 

Ash System 

Flow Diagram for Air Pollution Control 

Scrubbing System 

Flow Diagram of Secondary Treatment 

Methods 

Wastewater Treatment Flow Diagram 

Flow Diagram for Sludge Treatment 

Flow Diagram of Nitrification - 

Deni trification Process 

Model Waste Pretreatment Plant - 25 MW 

Generating Facility 

Model Waste Pretreatment Plant - 500 MW 

Generating Facility 

Cooling Water System Blowdown Treatment 

viii 
LIST OF TABLES 

Total Steam Electric Plants 

in the Contiguous United States 

Steam Electric Plants Discharging 

to Municipal Sewers in the Contiguous 

United States 

Statistical Parameters For the Three 

Modes of Normal Distribution - OnceThrough Condenser Cooling 

Statistical Parmeters For the Three 

Modes of Normal Distribution - 

Recirculating Condenser Cooling 

Raw Water Flows and Loadings - 

Condenser Cooling Systems 

Statistical Parmeters 'for the Three 

Modes of Normal Distribution - Boiler 

Makeup 

Statistical Parmeters for the Three 

Modes of Normal Distribution - Boiler 

Demi neral i zer 

Raw Waste Flows and Loadings - Water 

Treatment 

Effluent Flows and Loadings - Water 

Treatment 

Raw Waste Flows and Loadings - Boiler 

Bl owdown 

Raw Waste Flows and Loadings - 

Maintenance Clean-ing 

Ash Disposal Methods 

Raw Waste Flows and Loadings-- Ash 

Handl ing 

Effluent Flows and Loadings - Ash 

Handl i ng 
LIST OF TABLES (CONTINUED) 

Page 

Power Plant and POTW Flows V-69 

Raw Waste Flow5 and Loadings - Combined 

Discharge to POTW V-71 

End-of-Pi pe Treatment Methods VII-3 

Solid/Liquid Separation Systems VII-4 

Treatment of Major Pollutants VII-5 

Typical Composition of Boiler Chemical 

Cleaning Wastes VII-12 

Typical Composition of Boiler Fireside 

Wash Wastes VII-12 

Recovery Processes for Flue Gas 

Desulfurization Systems VII-20 

Wastewater Treatment Costs and Resulting 

Waste-load Characteristics for Typical 

Plant VIII-7 

Wastewater Treatment Costs and Resulting 

Waste-load Characteristics for Typical 

Plant VIII-8 

Summary of Capital Costs Oil and Gas 

Fired Plants - 25 MW Plant VIII-10 

Wastewater Treatment Cost and Resulting 

Waste-load Characteristics for Typical 

Plant VIII-13 

Wastewater Treatment Costs and Resulting 

Waste-load Characteristics for Typical 

Plant VIII-14 

Summary of Capital Costs Coal Fired 

Plant VIII-15 

Estimated Capital Costs - Chemical 

Wastes Pretreatment Plant VIII-20 

Assumed Unit Costs VIII-21 
LIST OF TABLES (CONTINUED) 

Page 

VIII-9 Operating Costs - Pretreatment of Low 

Volume and Metal Cleaning Wastes VIII-22 

VIII-10 Estimated Capital Cost - Cooling Water 

System Blowdown Treatment VIII-27 

VIII-11 Estimated Operating Costs-Cooling 

Water System Blowdown Treatment VIII-27 
DRAFT 

SECTION I 

CONCLUSIONS 

An engineering evaluation of steam electric power generating 

plants that discharge all or a portion of their aqueous 

wastes $0 publicly-owned treatment works (POTW's) was 

conducted to establish the basis for pretreatment standards. 

For the purpose of establishing such standards it was 

deemed practical to subcategorize the industry into the 

following waste-type subcategories: 

Condenser Cooling System 

Boiler Water Pretreatment 

Boi 1 er Bl owdown 

Maintenance Cleaning 

Ash Handling 

Drainage 

Air Pollution Control Devices 

Miscellaneous Waste Streams 

This subcategorization is identical to that presented in the 

development document for direct dischargers (14) in this 

industry with the deletion of Construction Activity and 

Low Level Radwastes. This subcategorization was found to 

be valid as examination of process characteristics, raw 

wastes and treated wastes were not found to be significantly 

different from those of direct dischargers. 

Conduct of the work involved contact with 49 steam electric 

power generating stations, representing 50 percent of the 

estimated 98 stations discharging chemicals wastes to a 

POTW. Engineering visits and data collection were made to 

22 stations. Sampling of raw and pretreated wastes was obtained 

from eight (8) stations. Additionally, prior work conducted by 

the EPA, data collected in response to NPDES and local 

discharge permit monitoring, industrial effluent data, and 

relevant literature prepared by the EPA and electrical trade 

journals were evaluated. 
DRAFT 

Based on the above evaluation, the following conclusions 

were reached: 

a There exists no significant difference between 

processes and corresponding effluents of the 

population of plants discharging to the POTW 

and those of direct dischargers. 

a The subcategorization developed above is valid 

for the purpose of establishing pretreatment 

standards. 

a Stations discharging to the POTW are capable 

of pretreating effluents to the degree 

of effluent removal attainable by application 

of the best practicable control technology 

currently available (BPCTCA) for direct 

dischargers. 

A survey of current industry practices has indicated that 

most plants provide little pretreatment of chemical type 

wastes at the present time. 
DRAFT 

SECTION I1 

RECOMMENDATIONS 

The €PA will propose standards after review and 

evaluation of the information included in this document. 
GENERAL 

DRAFT 

SECTION I11 

INTRODUCTION 

BACKGROUND 

The involvement of the Federal Government in water pollution 

control dates back to 1948 when Congress enacted the first 

comprehensive measure aimed specifically at this problem. 

At that time the Surgeon General, through the U.S. Public 

Health Service, was authorized to assist states in various 

ways to address the problem. The emergence of a national 

water pollution control program came about with the 

enactment of the Water Pollution Control Act of 1956 (Public 

Law 84-660). To date this law remains the basic law 

governing water pollution. It establishes the basic system 

of technical and financial assistance to states and 

municipalities, as well as enforcement procedures by which 

legal steps can be initiated against polluters. 

The present program dates back to the Water Quality Act of 

1965 and the Clean Water Restoration Act of 1966. Under the 

1965 Act, states were required to adopt water quality 

standards for interstate waters, and to submit to the 

Federal Government, for approval, plans to implement and 

enforce these standards. The 1966 Act authorized Federal 

participation in construction of sewage treatment plants. 

On amendment, the Water Quality Act of 1970, extended 

Federal activities into such areas as pollution by oil, 

hazardous substances, sewage from vessels, and mine drainage. 

Originally, pollution control activities were the 

responsibility of the U.S. Public Health Service. In 1961, 

the Federal Water Pollution Control Administration (FWPCA) 

was created in the Department of Health, Education and 

Welfare, and in 1966, the FWPCA was transferred to the 

Department of the Interior. The name was changed in early 

1970 to the Federal Water Quality Administration and in 

December 1970, the Environmental Protection Agency (EPA) was 

created by Executive Order as an independent agency outside 

the Department of the Interior. Executive Order 11574 on 

December 23, 1970, established the Permit Program, requiring 

all industries to obtain permits for discharge of wastes 

into navigable waters or their tributaries under the 

provisions of the 1899 River and Harbor Act (Refuse Act). 

The permit program immediately became involved in legal 

problems resulting in a court ruling that effectively 

stopped issuance of a significant number of permits. It did 

result in the filing with EPA, through the U.S. Army Corps 

of Engineers, of applications for permits which, represent a 
DRAFT 

complete inventory of industrial waste discharges. The 

granting of a permit under the Refuse Act was dependent on 

the discharge being able to meet applicable water quality 

standards. Although EPA could not specify methods of 

treatment, they could require minimum effluent levels 

necessary to meet water quality standards. 

The Federal Water Pollution Control Act Amendments of 1972 

(the "Act") made a number of fundamental changes in the 

approach to achieving clean water. One of the most 

significant changes was from a reliance on water quality 

related effluent limitations to a direct control of effluents 

through the establishment of technology-based effluent 

guidelines to form an additional basis, as a minimum, for 

issuance of discharge permits. The permit program under the 

1899 Refuse Act was placed under full control of EPA, with 

much of the responsibility to be delegated to the States. 

PURPOSE AND AUTHORITY 

Under the Act, the Environmental Protection Agency is 

charged with establishing pretreatment standards to protect 

the operation of publicly-owned treatment works and to 

prevent discharge of pollutants which pass through such 

works inadequately treated. 

As part of this Act, Section 307(b) states that the 

Administrator shall "publish proposed regulations establishing 

pretreatment standards for introduction of pollutants into 

treatment works (as defined in Section 212 of this act) 

which are publicly owned for those pollutants which are 

determined not to be susceptible to treatment by such 

treatment works or which would interfere with the operation 

of such treatment works. Pretreatment standards under this 

section shall specify a time for compliance not to exceed 

three years from the date of promulgation." 

This report is prepared for the purpose of developing 

pretreatment standards for existing sources. Pretreatment 

Standards for new sources are required under Section 307(c) 

of the Act have been promugated October of 1974, (together 

with the effluent guidelines for the Steam Electric Power 

Plant Source Category). 

SCOPE --- OF WORK AND TECHNICAL APPROACH 

The pretreatment standards proposed herein were developed in 

the following manner. The list of plants that discharge to 

a POTW was first studied for the purpose of determining 

whether separate standards would be re-quired for different 

divisions within the list. The analysis was based upon fuels 

used, production process employed,' wastewater pretreatment 

at plant sites, process employed by the POTW receiving plant 

wastewater, and other factors. The raw waste characteristics 

for each subcategory were then identified. This included an 

analyses of (1) the source and volume of water used in the 
DRAFT 

process employed and (2) the constituents (including thermal ) 

of all wastewaters including constituents which result in 

taste, odor, and color in water. The constituents of 

wastewaters which should be subject to pretreatment standards 

were identified. 

The full range of control and pretreatment technologies 

existing within each subcategory was identified. This 

included identification of each distinct control and 

pretreatment technology, including both in-plant and 

end-of-process technologies, which are existent or capable 

of being designed for each subcategory. It also included an 

identification of the amount of constituents and the chemical, 

physical, and biological characteristics of pollutants. 

Effluent levels resulting from the application of each of 

the pretreatment and control technologies were also 

identified. The problems, limitations, and re1 iability of 

each pretreatment and control technology were also identified. 

In addition, the nonwater quality environmental impact, such 

as the effects of the application of such technologies upon 

other pollution problems, including air, and solid waste, 

were also identified. The energy requirements of each of 

the control and treatment technologies were identified as 

we'll as the cost of the application of such technologies. 

The information, as outlined above, was then evaluated in 

order to determine what levels of technology are available 

for effluent reduction. In identifying such technologies, 

various factors were then considered. These included the 

total cost of application of technology in relation to 

effluent reduction benefits to be achieved from such 

application, the age of equipment and facilities involved, 

the process employed, the engineering aspects of the 

application of various types of control techniques, process 

changes, nonwater quality environmental impact (including 

energy requirements), and other factors. 

Data for identification and analyses were obtained from a 

number of sources. These sources included EPA research 

information; EPA, state, and local environmental personnel; 

trade associations; published literature; qualified technical 

consultation; historical information on effluent quality and 

quantity; and on-site visits including analytical programs 

and interviews at steam electric plants throughout the 

United States which were known to have above average waste 

pretreatment facilities. All references used in developing 

the pretreatment standards reported herein are listed in 

Section XI of this document. 
DRAFT 

Twenty-two operating plants were visited and eight were 

sampled. Composite samples over a sixteen hour period were 

obtained from these eight plants and were analyzed for 

parameters mentioned in Section V. Information was obtained 

from as many as fifteen (15) plants for each waste-type 

subcategory. Both in-process and end-of-pipe data were 

obtained as a basis for determining water use rates 

capabilities and effluent loads. Permit application data 

was of value for the purposes of this study when such data 

covered outfalls serving only skeam electric power operations. 

Cost information was obtained directly from industry during 

plant visits, from engineering firms, equipment suppliers, 

and from the literature. These costs have been used to 

develop general capital, operating, and total costs for each 

pretreatment and control method. This generalized cost data 

and specific information obtained from plant visits was used 

to estimate cost effectiveness in Section VIII and elsewhere 

in this report. 

Certain plants were selected for in-depth analysis from the 

total population of those visited. These plants were 

plants discharging representative waste types or exhibiting 

superior performance in pollutant discharge or having 

substantial quantities of historic effluent data. 

The following selection criteria were developed and used for 

selection of plants to be included in this study. 

0 Discharge - of representative wastes types 

Plants that discharge types or quantities 

of waste representative of those delineated in 

Section IV. 

e Water management practices 

Plants that had good management practices 

such as good process and quality control, good maintenance, water reuse, conservation, and 

in-plant water segregation. 

a Air pollution and solid waste control 

Plants that had overall effective air and solid 

waste pollution control, in addition to 
DRAFT 

water pol 1 ution control technology. Care was 

taken to insure that all plants chosen have 

minimal discharge to the POTW and that 

sites are not those which exchange one 

form of pollution for another. 

8 Effluent pretreatment methods and their 

effectiveness 

Plants were those using technology 

approaching BPCTCA, operating controls, and 

operational reliability. Pretreatment methods 

considered included such process modifications 

as may significantly reduce effluent loads, as 

well as conventional pretreatment processes. 

o Plant facilities 

Plants that had all the facilities 

normally associated with the generation of 

electric power from steam. Typical facilities 

generally were plants which have all normal process 

steps carried out on-site. 

o Plant management philosophy 

Plants whose management insists 

upon effective equipment maintenance, good 

housekeeping practices, and efficient land use. 

Geographic location 

Factors such as land availability, rainfall, feed 

water quality, and differences in state and local 

standards were also considered. 

o Characteristics of publicly-owned treatment works 

receiving power plant discharges 

Size, process employed, pollutants not susceptible 

to treatment, and any pollutants which would 

interfere with normal operation at a POTW were 

taken into consideration. 
DRAFT 

GENERAL DESCRIPTION OF THE INDUSTRY 

The Steam Electric Power Industry is made up of 1273 plants 

throughout the contiguous United States. Of these plants an 

estimated 7.7 percent or 98 plants discharge wastewaters to 

publicly-owned treatment works and are thus covered by the 

scope of this document. In this study 49 plants discharging 

to POTW's were contacted. 

Statistics for this section were estimated based on a truly 

random sampling of steam electric power plants contained in 

the "Environmental Assessment of Alternative Thermal Control 

Strategies for the Electric Power Industry" by Michelle M. 

Zarubica of the Cffice of Planning and Evaluation of the 

Environmental Protection Agency (18). 

Steam Electric plants discharging to the POTW tended to be 

smaller on the average than plants discharging to surface 

water. These plants averaged about 150 MW for a total 

capacity of 14,500 MW which compares with an average capacity 

and total generating capacity of about 400 MW and 506,700 MW 

for the entire Steam Electric Industry. (See Tables 111-1 

and 111-2). Of these plants, an estimated 72 percent are 

publicly-owned and 28 percent are investor owned. 

Most of the Steam Electric plants that discharge to POTW's 

(68 percent) use gas as their principal fuel compared to 31 

percent for the entire industry Figures 111-1 and 111-2. 

Conversion of some plants from gas to oil is expected due to 

shortage of natural gas. 

Plants which discharge wastewaters to POTW's tend to be 

older than plants which discharge to surface waters. Tables 

111-1 and 111-2 show that 29 percent of the plants which 

discharge to POTW's were built since 1960 as compared to 38 

percent for the entire population. Also, plants built since 

1960 represent 48 percent of the generating capacity of 

plants discharging to POTW's compared to 78 percent for the 

entire Steam Electric Industry. (See Figures 111-3 and III4). 

Approximately 24 percent of a1 1 electrical gene'ration is 

nuclear powered but no plants of this type were observed to 

discharge to the POTW. Nonetheless, nuclear plants are 

included in this document, since their chemical waste 

discharges are similar in nature to those discharged by nonnuclear facilities (14). 

Steam Electric plants discharging to POTW's are located in 

all regions of the country with somewhat higher than average 

concentrations in the Midwest and in California. 
DRAFT 

Table 111-1. Total Steam Electric Plants in the 

Contiguous United States 

Total Number of Plants = 1273 

Total Number of Units = 3011 

Total Number of Megawatts= 506,654 

Average Station Size = 398 

Percentage of Plants Confirmed as Discharging 

to Municipal Sewers - by Number = 7.7% 

by Megawatts = 2.9% 

Principal Percentage by Percentage by 

Unit Fuel Number Megawatts 

Gas 

Oi 1 

Coal 

Nuclear 

Percentage by Percentage by 

Unit Built In Number Megawatts 
DRAFT 

Table 111-2. Steam Electric Plants Discharging to 

Municipal Sewers in the Contiguous United States 

Total Number of Plants = 98 

Total Number of Units = 277 

Total Number of Megawatts = 14504 

Average Station Size = 148 

Principal Percentage by Percentage by 

Unit Fuel Number Megawatts 

Gas 

Oi 1 

Coal 

Nuc 1 ear 

Percentage by Percentage by 

Unit Built In Number Megawatts 
DRAFT 

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GAS 

OVERALL PLANTS 

POPULATION DISCHARGING 

TO POTW'S 

OIL COAL NUCLEAR 

PRINCIPAL FUEL 

Figure 111-1. Principal Fuel Use by Number 

111-9 
PERCENTAGE OF MEGAWATTS --I 

-2 N C3 P ul rn V 03 cD 0 

0 0 0 0 0 0 0 0 0 0 
DRAFT 

YEAR PLANT BUILT 

OVERALL DISCHARGING 

POPULATION TO POTW'S 

Figure 111-3. Year of Construction by Number 

111-11 
DRAFT 

1910 1930 1940 1950 

YEAR PLANT BUILT 

OVERALL PLANTS 

POPULATION DISCHARGING 

TO POTW'S 

Figure 111-4. Year of Construction by Megawatt 

111-12 
DRAFT 

Process Description 

The "production" of electrical energy involves utilization 

and conversion of chemical or nuclear energy. Present day 

methods of utilizing energy of fossil fuels are based on a 

combustion process, followed by steam generation to convert 

the heat first into mechanical energy and then to convert 

the mechanical energy into electrical energy. The maximum 

theoretical efficiency that can be obtained in converting 

heat to work is limited by the temperatures at which the 

heat can be absorbed by the steam and discarded to the 

environment. The upper temperature is limited by the 

temperature of the fuel bed and the structural strength and 

other aspects of the boiler. The lower temperature is 

ideally the ambient temperature of the environment, although for practical purposes the reject temperature must be set by 

design significantly above the highest anticipated ambient 

temperature. Within these temperatures, efficiencies are 

limited to about 40 percent regardless of any improvement to 

the machines employed. For any steam electric power 

generation scheme, therefore, a minimum of 60 percent of 

the energy contained in the fuel must be rejected to the 

environment as waste heat (14). 

Fossil-fueled steam electric power plants produce electric 

energy in a four-stage process, shown in Figure 111-5. The 

first operation consists of the burning of the fuel in a 

boiler and the conversion of water into steam by the heat of 

combustion. The second operation consists of the conversion 

of the high-temperature, high-pressure steam into mechanical 

energy in a steam turbine. The steam leaving the turbine is 

condensed to water, transferring heat to the cooling medium, 

which is normally water. The turbine output is conveyed 

mechanically to a generator, which converts the mechanical 

energy into electrical energy. The condensed steam is 

reintroduced into the boiler to complete the cycle. 

The theoretical water-steam cycle employed in steam electric 

power plants is known as the Rankine cycle. Actual cycles 

in power plants only approach the performance of the Rankine 

cycle because of practical considerations. Thus, the heat 

absorption does not occur at a constant temperature, but 

consists of heating of the liquid to the boiling point, 

converting the liquid to vapor and superheating (heating 

above the saturation equilibrium temperature) the steam. 

Superheating is necessary to prevent excess condensation in 

the turbines and results in an increase in cycyle efficienty. 

Reheating, the raising of the temperature above saturation of 

the partially expanded steam, is used to obtain improvements in 

efficiency and again to prevent excess condensation. Preheating 
I 

St earn 

Fuel Inlet 

Boiler 

Ash outlet 

Electric 

Generator / 

Power 

Condenser r 7 

-i 

Cooling Water In 

+ Cooling Water Out 

FIGURE 111-5 

Process trow Diagram 

Steam Electric Power Industry 
DRAFT 

of condensate to near temperatures with waste heat, is also 

used for this purpose. Condensers cannot be designed to 

operate at theoretically optimum values because it would 

require infinitely larger equipment. All of these divergences 

from the optimum theoretical conditions cause a decrease in 

efficiency and an increase in the amount of heat rejected 

per unit of production. As a result, only a few of the 

larger and newer plants approach even the efficiencies possible 

under the ideal Rankine cycle. Also, as a result of second 

law limitations, modifications of the steam cycle of an 

existing plant are not likely to result in significant 

reductions in heat rejection. 

Publicly-Owned Treatment Works (POTW) 

The POTW process is broken down into three basic treatment 

methods; primary, secondary, and tertiary. Primary treatment 

consists of the removal of coarse materials, settleable 

solids, oil and grease, floating material, and the 

reduction of biological oxygen demand. Most POTW's employ 

secondary treatment which converts soluble and colloidal 

organic material into settleable flocculant material that 

can be removed by sedimentation. Secondary treatment is 

of.ten enhanced by the addition of chemicals such as iron, 

aluminum salts, and polymeric flocculants. The use of terti3ry 

treatment processes are still uncommon and include the 

removal of chemical constituents not affected by primary and 

secondary treatment. Tertiary treatment is intended to 

remove chemicals which promote algae growth and unwanted 

aquatic vegetation. 

The POTW's receiving wastewaters from Steam Electric plants 

vary in size and treatment process employed. Plant size is 

determined by human population and industrial waste load of 

the area served. Those contacted in this study ranged from 

200,000 gpd to 350,000,000 gpd in size. Treatment methods 

are determined by flow, waste load pollutant constituents, 

economics, energy and removal requirements, and plant age. 

There are a large number of wastewater treatment processes 

in use whose application is related both to the characteristics 

of the waste and the degree of treatment required. These 

processes are shown in Figure 111-6. 
P KI MARY I SECONDARY / TERTIARY I 

TREATMENT , TREATMEIIT TREATMENT 

Raw ~astc*ater - 

I - 6 - 

Coaqulatlm Recetvlng 

- and at en 

Sedlmntrttm 

- 

Synnfng and 

rrlt Rmovrl 

Neutral l zrtlon 

Chemlcal 

Addltton and 

tosgulrtlm Eqwllzrtlon and Storage 

Flltratlon irli Controlled or 

- Transported Otscharge 

Trlckllng 

Fllter 

Absorptlm Clq Ocean 

Otrposal 

Aerated P Appllcatlon 

or trow*ater - Scecrge Dlgestlon or 

I - Vet Cmbustlon 

1 Indmrrtlon I 

- Stablllzatlon - Basin 

Injection 

Thlckenlng 

Grrvlty or P- Flotrtlm 

Figure 111-6. Nastewater Treatment Sequence 
DRAFT 

SECTION IV 

INDUSTRY CATEGORIZATION 

INTRODUCTION 

An evaluation of steam electric power industry stations 

discharging chemical wastes to publicly-owned treatment 

works (POTW's) was necessary to determine whether 

categorization and subcategorization would be he1 pful in the 

preparation of effluent pretreatment standards for this 

industry. From this evaluation, steam electric industry 

stations discharging to POTW's have been categorized 

according to individual industrial waste sources. 

Subcategorization was based on distinguishing factors within 

groups of plants. 

This method of categorization was also used and is discussed 

in detail in the "Development Document for Effluent 

Limitation Guidelines and New Source Performance Standards 

for the Steam Electric Power Generating Category" October 

1974 (18). In this study on pretreatment, however, low level 

radioactive wastes are not addressed. 

The basis of evaluation of plants in the industry will be a 

combination of the appropriate waste sources for a particular 

power plant. Guidelines will be established for each waste 

source and can then be applied and utilized in the manner of 

a building block concept. In the case of combined waste 

streams the appropriate guidelines will be combined and 

weighted proportional to stream flow. The eight categories 

are presented in Table IV-1. 

The following were considered for industry categorization: 

age, size, fuel, geography, mode of operation, raw water 

quality, volume of water used, and pretreatment technology. 

INDUSTRY CATEGORIZATION 

This industry has been categorized according to the individual 

industrial waste source. Marked differences were observed 

in fuel type, boiler, pretreatment, and maintenance waste 

streams. These differences were the basis for subcategorization 

Although age, size, geography, mode of operation, and feed 

water hardness did vary greatly, these characteristics do 

not appear to directly affect discharges. Statistical 

analyses discussed in Section I11 and information found in 

Sections V and VII were utilized in reaching these conclusions. 
DRAFT 

TABLE IV-1 

I I I. 

IV. 

VI. 

VII. 

VIII. 

Condenser Cooling System 

A. Once-Through 

B. Recirculating 

Boiler Water Pretreatment 

A. Clarification 

B. Softening 

C. Ion Exchange 

D. Evaporator 

E. Fi 1 trati on 

F. Other Treatment 

Boiler or PWR Steam Generator 

A. Blowdown 

Maintenance Cleaning 

A. Boiler or PWR Steam Generator Tubes 

B. Boiler Fireside 

C. Air Preheater 

D. Misc. Small Equipment 

E. Stack 

F. Cooling Tower Basin 

Ash Handling 

A. Oil-Fired Plants 

1. flyash 

2. bottomash 

B. Coal-Fired Plants 

1. fly ash 

2. bottom ash 

Drainage 

A. CoalPile 

B. Contaminated Floor and Yard Drains 

Air Pollution Control Devices 

A. SO2 - Removal 

Miscellaneous Waste Streams 

A. Sanitary Wastes 

B. Plant Laboratory and Sampling Systems 

C. Intake Screen Backwash 

D. Closed Cooling Water Systems 
DRAFT 

FACTORS CONSIDERED 

Power plants discharging to the POTW's tend to be older than 

surface water discharging plants. In steam electric power 

plants, individual generation units are often installed at 

different times over a number of years. Newer units tend 

to be thermally more efficient then older plants and use 

less fuel per killowatt hour of electricity produced. 

Because of fuel economics newer units generally tend to be 

used for base load production while other units are employed 

as peaking and cyclic units. Increased fuel efficiency may 

reduce wastewater loads such as ash transport water, 

wet scrubber water, etc. However, since age of units varies 

within even a single plant and no correlation can be drawn 

between processes, types of waste discharge, and plant age, 

age is not regarded as a suitable basis for categorization. 

Size 

Although the size of steam electric power plants discharging 

to POTW's various significantly, the basic process is common 

to all facilities. Plant size was found to have little 

affect on quantity of treated effluent. Plants discharging 

to sanitary sewers tend to be smaller than power plants 

discharging to surface water. Therefore, size is rejected 

as criteria for categorization. 

Fuel 

Plants discharging to POTW's were identified as burning all 

three major fossil fuels, coal, oil, and gas. In contrast to 

the entire population of steam electric plants in the U.S. 

the majority of plants contacted in this study use gas as 

fuel. Fuel-related wastes such as ash control transport 

water and coal pile drainage, can contribute to wastewater 

discharge. The presence of sulfur in the fuel may require 

scrubbers. Therefore, the affect of different fuels on certain 

processes and effluents is useful for subcategorization. 

Geography 

Usually, steam power plants that discharge to the POTW's are 

located near or within municipal boundaries. Most of the 

plants contacted were, in fact, situated in downtown areas. 

Plants discharging to the sewers were located in nearly all 

geographical regions of the United States. It is noted that 

recent trends toward larger power generating stations, and 

the institution of mine-mouth coal fed plants, have resulted 

in increased rural plant construction and a reduced 

number of municipal ly-1 ocated plants. 
DRAFT 

Since plant processes do not vary according to geography, 

all plants covered in this study are located in or near 

municipalities, geography is rejected as a criteria for 

categorization. 

-- Mode of Operation 

Despite the fact that peaking and cyclic stations are older 

and smaller than base load stations, many units of plants 

are often utilized for extended periods for either purpose. 

Additionally, the basic operation is independent of the 

type of service provided. Therefore, mode of operation is 

rejected as a criteria for categorization. 

-- Raw Water Quality 

After study of the affects of raw water quality on effluent 

discharge, quality of raw water was determined not to be a 

criteria for categorization. Hardness would indeed affect 

operation by increasing the frequency of regeneration of the 

deionizer or recharging the softener. The harder the raw 

water the more frequently the deionizer anion and cation must 

be regenerated and the hot lime and zeolite units have to be 

recharged. Effects of raw water quality are included in the 

Boiler Water Pretreatment Category. 

Volume - of Water Used 

Water use varies greatly even among plants of approximately 

the same size. It depends primarily on the type of cooling 

system, the cost and quality of the water supply, and the 

extent to which water conservation is practiced by individual 

plants. Because of wide variations in water consumption 

among individual plants of this industry, water use was not 

found to be acceptable criterion for categorization. 

Pretreatment Technology 

A wastewater treatment system should be an integral part of 

a plant's water management program. It should be designed 

on the basis of the quality and quantity of the wastewater 

to be treated and its ultimate disposal. Many plants in the 

industry discharge their wastewater effluent to municipal 

sewer systems; others discharge only a portion. The extent 

of pretreatment varies widely from no pretreatment to 

integrated plants using complex systems such as equalization, 

neutralization, etc. 

No pattern was found for pretreatment technology in the 

industry, thus it is not a suitable basis for categorization. 
DRAFT 

SECTION V 

WATER USE AND WASTE CHARACTERIZATION 

INTRODUCTION 

Specific water uses and the waterborne wastes involved in 

steam electric plants discharging into pub1 icly-owned treatment 

works (POTW) are described in this section, along with other 

process waste materials. Process waters are characterized 

as raw waste loads from specific processes associated with 

the production of electricity. These are generallly 

expressed as grams per megawatt hour (MWH) of electricity 

generated. Water uses are given in terms of liters per 

MWH, or as liters per day and waterborne waste loads in 

mg/liter or grams per MWH. The waste treatments used by 

both power plants and POTWs are described, and amounts and 

types of waterborne waste effluents after treatment are 

characterized. 

PRINCIPLES - OF OPERATION - OF STEAM ELECTRIC POWER PLANT 

In a steam electric power plant, thermal energy, produced 

by rapid chemical combustion or nuclear fission reaction, 

is first tranformed into high pressure, high temperature 

steam, and then to mechanical energy through expansion of 

the steam in a turbine. The process can be divided into 

four stages. The first operation consists of fuel 

combustion in the boiler furnace to produce high pressure, 

superheated steam. The steam is conveyed to a turbine 

where it is allowed to gradually expand and cool in the 

various turbine stages to convert the thermal energy into 

electrical energy via mechanical energy. In the third 

operation the steam exiting from the final stage of the 

turbine is condensed to water, transferring the heat to a 

cooling medium, which is normally water. Finally the 

condensed steam is reintroduced into a boiler by a pump 

to complete the cycle. 

The power cycle components can be divided into three 

principal units: 

8 steam boiler 

0 steam turbine 

8 condenser 
DRAFT 

Each of the cycle components provides an energy transfer 

and transformation function necessary to convert the heat 

energy into useful work. The following are descriptions of 

these three units. A more extensive discussion on the 

principles of design and operation of steam electric power 

plants can be found elsewhere (14,16). 

Boi 1 ers 

All boilers use the same basic design, that is, they are 

large multi-tube heat exchangers surrounded by a furnace. 

The feedwater circulates within the tubes where it is heated, 

vaporized, and superheated producing steam to drive the 

steam turbine generators. Many different boiler 

arrangements are used. Oil and gas-fired boilers are simpler 

than coal-fired boilers because 1 iquid and gaseous fuels do 

not require the conveyers, pulverizers, and ash collection 

equipment necessary in coal-fired boilers. The boiler 

structure may be either exposed or enclosed depending on 

local weather conditions, and is usually very large to 

accommodate the large tube surface areas required. Air 

heaters, economizers, and other sections of the boiler 

are used to extract the maximum amount of heat from the 

combustion gases before they are discharged to the 

environment. This serves to increase the boilers efficiency: 

the ratio of heat converted to steam to the heat input 

value of the burning fuels. Modern power boilers are able 

to achieve 85 to 90 percent efficiencies; the remaining 

10 to 15 percent of the input heat value is discharged to 

the environment with the exhaust gases. This loss is 

referred to as the "stack loss." Figure V-1 shows a typical 

boiler for an oil-fired furnace. 

Steam Turbine 

The steam turbine consists of alternate rows of nozzles and 

blades on wheels. Each row of nozzles and its associated 

row of blades is called a turbine stage. As the steam 

expands through the nozzles, the pressure decreases and 

the velocity and specific volume increase. When the steam 

comes in contact with the blades a part of the momentum 

(kinetic energy) is transferred to the blades. The turbine 

shaft and generator are caused to rotate and electricity 

is produced. 

DRAFT 

There are many different types of turbines and turbine 

arrangements in use. Most of the turbines are of the 

condensing type, discharging the steam from the last stage 

at below atmospheric pressure. The efficiency of a 

turbine is highly sensitive to the exhaust pressure (back 

pressure). Turbines designed for once-through cooling 

systems are generally operated at lower back pressures than 

that designed for closed cooling systems. 

In most turbine arrangements a portion of the steam leaves 

the casing before the final stage. This type of turbine 

is referred to as extraction turbine. The extracted steam 

is used for feedwater heating purposes. In some turbines, 

a portion of the steam is extracted from intermediate stages, 

reheated in the boiler, and returned to the turbine or another 

turbine as a means of improving overall efficiency. 

Steam Condensation 

Steam leaving the final stage of the turbine is condensed 

into water in the condenser. This is essentially a very 

large shell and tube heat exchanger designed to withstand 

the high vacuums associated with modern steam turbine 

power cycles. Heat is transferred from the exhaust steam to 

an external cooling water system which may draw water from 

a surface or underground source, or from the cooling tower. 

There are two types of condensers; the single-pass and the 

two-pass condensers. If all the water flows through the 

condenser tubes in one direction, it is call a single-pass 

condenser. If the water passes through one half of the 

tubes in one direction and the other half in the opposite 

direction, it is referred to as a two-pass condenser. A 

single~pass condenser usually requires a larger water supply 

than a two-pass condenser and generally results in a lower 

temperature rise in the cooling water. Many condensers 

have divided water boxes so that half the condenser can be 

taken out of service for cleaning while the unit is kept running under reduced loads. Condensers are periodically 

cleaned mechanically as part of regular scheduled maintenance 

procedures. Some plants employ continuous on-line mechanical 

cleaning. Figure V-2 shows a typical single-pass condenser. 
STEAM FROM TURBINE EXHAUST 

CONDENSATE 

OUT COOLING WATE 

(HOT) (COLD) 

F1GURE.V-2. Single-pass Condenser 
DRAFT 

WATER -- USE AND WASTE CHARACTERIZATION - BY CATEGORY 

The results obtained on power plant wastes from visiting 

twenty-two plants, sampling eight, and reducing and analyzing 

the data do not differ substantially from those reported in 

the "Development Document for Effluent Limitations Guidelines 

and New Source Performance Standards for the Steam Electric 

Power Generating Point Source Category" (14). 

The majority of the water used in steam electric generating 

plants is for condenser cooling water. Lesser amounts are 

used for boiler makeup water, bearing cooling water, 

equipment cleaning, and other miscellaneous purposes. 

Figure V-3 shows a typical Steam Electric process diagram 

with wastewater sources. 

Waste discharges can be classified under two categories: 

continuous discharges, and intermittent discharges. Wastes 

are produced on a continuous basis from the following (if 

applicable): cooling water systems, ash handling systems, 

wet-scrubber air pollution control systems, and boiler 

blowdowns. Waste discharges are produced intermittently by 

boiler water pretreatment operations such as ion exchange, 

filtration, clarification, and evaporation. Intermittent 

discharges are also produced during miscellaneous equipment 

cleaning operations and from sanitary and laboratory wastes. 

The following discussion is a categorization and description 

of water uses and waste discharges within typical generating 

plants. Much of the following has been summarized from 

Reference 14, which contains a more detailed discussion of 

water use and waste characterization. 

CONDENSER COOLING WATER 

All condenser cooling systems can be classified as (1) oncethrough, or (2) recirculating. 

Once-Through Systems 

In areas where large amounts of water are available from 

natural sources, the simplest method of condensing steam is 

to withdraw water from the source, pass it through a condenser, 

and discharge it back into the same source at a higher 

temperature. Biocides such as chlorine or hypochlorites are 

usually added to systems of this type to minimize biological 

growth within the condenser. Once-through cooling systems 

have no waste discharges to POTWs, 
To Atm sphere f 

a 

1 1 i 

Fly Ash -"em$=rls 

Uater Collection ---A ---- + 

and/or s02 Chemicals Scrubbing 

Device 

I Wastewater To 

Raw @Treatment 

Mate 

Once Through 

Conb'n Air- Cooling Water 

ttng Cooltng Uater 

a 

hemi cal s 

Makeup Waterd-+ 

q~unof f ]e Chemicals 

System Water 

Floor and 

Yard Drains ---.f~astewaterle Waste- I ~astes, intake Screen 

Backwash, Closed Cooling 

Water Systems Construe- I tion. ~ctivity I 

LEGEND: 

Liquid Flow 

------- Gas 6 Steam Flow 

Chemicals 

a+-a-+ Optional Flow 

FIGURE V- 3. Fossil-Fueled Steam Electric Power Plant-Typical Flow Diagram 
DRAFT 

Recirculating Systems 

If sufficient water is not available for a once-through 

system, condenser cooling water must be recirculated within 

the plant. This is accomplished by providing some sort of 

artificial cooling device, such as a pond or a cooling tower, 

to cool the cooling water by evaporating a portion of 

it before recirculating it back to the condenser. Ponds are 

used only where large areas of inexpensive land are available, 

since a large plant may require over 1,000 acres of pond 

surface. Cooling towers may be either of the wet or dry 

types, and are used where sufficient land for ponds is 

unavailable or too expensive. Since all cooling devices 

(except dry cooling towers, which are rare) transfer the 

process waste heat to the atmosphere by evaporation 

additional water must be added to the system to make up 

for these losses due to evaporation, drift and blowdown. 

Various chemicals are added to recirculating cooling systems 

to prevent biological growth in cooling towers and to control 

scale accumulation and corrosion in condensers. These 

include biocides such as chlorine, hypochlorites, and organic 

chromates; and corrosion inhibitors such as organic phosphates, 

sodium phosphate, chromates, and zinc salts. 

Wastes that may be discharged to a POTW from recirculating 

cooling systems originate from cooling tower blowdown. 

Blowdown is the discharge from the cooling tower of 

a portion of water either constantly or intermittently 

to prevent the concentration buildup of salts that may form 

scale deposits within the condenser. This blowdown will 

contain calcium, magnesium, and sodium cations in combination 

with carbonate, bicarbonate, sulfate, and chloride anions. 

Additionally, various amounts of the conditioning chemicals 

will be present. 

The rate of blowdown can be estimated by the use of the 

following equation: (Ref. 1) 

where: B is the blowdown rate; Ev is evaporation 

rate; D is drift losses; and C is the 

cycles of concentration defined as the 

ratio of the concentration of a critical 

chemical species in the blowdown to that 

in the makeup water. 
DRAFT 

The evaporation rate (Ev) from cooling towers averages 

about 1.5 percent of the cooling water flow for every 10°C 

rise in cooling water temperature as the water passes 

through the condensers. The drift rate (D) for new cooling 

towers is about 0.005 percent of the cooling water flow for 

mechanical draft towers, and about 0.002 percent for natural 

draft towers. Cycles of concentration (C) is an expression 

of the buildup of any constitutent in the cooling water 

system from its original value in the makeup water. In 

practice, C is usually between 4 and 6. For very high 

quality makeup water, C may be as high as 15, and for very 

saline water, C may be as low as 1.2-1.5. 

Figure V-4 shows typical once-through, and recirculating 

cooling system flow diagrams. Figures* V-5 and V-6 show 

two types of wet cooling towers. 

Water Use 

Once-Through Systems. Seven of the twenty-two plants 

surveyed use a once-through cooling system to remove the 

waste-heat from the process. The water usage in li-ters per 

MWH at the plant studied is given below: 

Plant No. Water Usage LiterIMWH 

A similar but narrower range of water use for once-through 

condenser cooling of 1.105 to 3.5~105 - liters per MWH was 

reported elsewhere (14). Plant No. 6421 has a higher 

than normal water usage because of intermittant operation. 
DRAFT 

EXHAUST STEAM 

FROM TURBINE 

EXHAUST STEAM 

FROM TURBINE 

a Y 

EVAPORATION 

SURFACE CONDENSER .WATER -b 

* 

DISCHARGE TO 

)SURFACE WATER 

FIGURE V-4 . Once-Through (top) and 

Recirculating (bottom) Cooling 

Systems 

v 

CONDENSATE 

t I 

1 . - 

f 

COOL1 NG 

TOWER 

CONDENSER 

MAKEUP 

I WATER 

CONDENSATE 

COOLING WATER 
DRAFT 

f SPRAY ELIMINATOR 

WATER 1N-z 

0 

m 

PUMP 

FIGURE V-5 . Diagram of Wet Forced-Air Cooling Tower 
DRAFT 

AIR 

OUTLET 

HOT W 

DISTR 

AIR 

INLET 

ER 

BAS I N 

FIGURE V-6 

Natural-Draft Wet Cooling Tower 

(Counter-Flow) 
DRAFT 

Figure V-7 is a plot of once-through cooling water, corrected 

to fit normal distribution, against the cumulative percentages 

of involved plants expressed as probits (standard deviation 

plus five). The statistical parameters for the three modes 

of normal distribution examined are listed in Table V-1. 

The statistical approach used is described in Appendix A 

of this report. The results of the statistical analysis 

suggest an almost perfect fit of the corrected data to the 

three-parameter modes of normal distribution. This is 

indicated by the coefficient of determination which measures 

the "goodness of fit" of the regression line. This value 

indicates that fitting of a least squares straight line 

accounts for almost 100 percent of the data variance. 

The water use data were also plotted against production rate 

to determine the effect of the plant size on the quantity of 

water used. Figure V-8 shows a log-log diagram of water 

use for once-through condenser cooling as a function of 

production rate. Also shown in Figure V-8 are the regression 

line and the 95 percent confidence limits. The statistical 

regression analysis coefficient expressed as logarithms are 

given be1 ow. 

Statistical Parameters Value 

Slope -0.13 

Intercept 6.14 

Coefficient of determination 0.11 

Standard error of estimated 

water use on production rate 0.23 

Standard error of intercept 0.17 

Standard error of slope 0.94 

The results of the statistical analysis suggest, at best, 

a poor correlation between water use for once-through 

cooling system and production rate. This is indicated by 

the value calculated for the coefficient of determination 

which indicates that a least squares regression line 

accounts for only 11 percent of the data variance. 

Although the overall trend suggests that the water use 

may decrease slightly with increasing production rate, 

this is not substantiated by the statistical analysis. 
DRAFT 

5.0 6.0 7.0 

PROBITS 

FIGURE V- 7 . Normal Distribution Diagram for ; Normalized 

Once-Through Usage Data 
Table V-1. STATISTICAL PARAMETERS FOR THE THREE MODES 

OF NORMAL DISTRIBUTION - ONCE-THROUGH CONDENSER COOLING 

Statistical 

Parameter \ 

Mean 

Variance 

3rd Moment 

4th Moment 

Coefficient of Skewness 

Coefficent of Kurtosis 

Correction Constant 

Slope 

Intercept 

Coefficient of Determination 

99% Confidence Limit 

Arithmetic 

x~ o4 

Logarithmic 

x1~4 

3 Parameters 

Logarithmic 

x1 o4 
DRAFT 

Io5 Production Rate 1 o6 

(MWH) 

FIGURE V-8 Qnce-Through Cooling Water- Use vs. Annual 

Production Rate 
DRAFT 

Recirculating Systems. Twelve of the 22 plants surveyed 

use a recirculating condenser cooling system to remove 

waste heat from the process. Waste heat is removed 

from the cooling water by means of evaporation and blowdown. 

Water usage in liters per MWH at the plants studied is given 

below: 

Plant No. 

9600 

9650 

9369 

9371 

881 6 

9585 

8696 

81 35 

8392 

6293 

7308 

8875 

Figure V-9 is a plot of recirculating condenser cooling 

water, corrected to fit normal distribution, against 

cumulative percent of involved plants expressed as probits 

(standard deviation plus five). The statistical parameters 

for the three modes of normal distribution examined are 

listed in Table V-2. The statistical approach used is 

described in Appendix A of this report. The coefficient of 

determination calculated for the three parameter mode of 

normal distribution, which measures "goodness of fit" 

of the regression line to corrected data, indicates a 

good fit to the n~rmal distribution. This value indicates 

that the least squares straight line accounts for 92 percent 

of the data variance. 

The water usage data was also plotted on log-log paper 

versus the production rate to determine the effect of the 

plant size on the quantity of water used. Figure V-10 

shows the plotted data, the regression line, and the 95 

percent confidence limits. The statistical regression 

analysis coefficients expressed as logarithms are given 

below: 

Statistical Parameters Value 

Slope 0.06 

Intercept 3.08 

Coefficient of Determination 0.00 

Standard error of estimated 

water use on production rate 0.77 

Standard error of intercept 2.09 

Standard error of slope 0.37 
DRAFT 

3.0 4 .O 5.0 6.0 7 .O 

PROBITS 

FIGURE V- 9 . Norrnal Distribution Diagram for Normalized 

Cooling \dater Usage Data 
Table V-2. STATISTICAL PARAMETERS FOR THE THREE MODES OF NORMAL 

DISTRIBUTION - RECIRCULATING CONDENSER COOLING 

Mode of Normal 

Statistical 

Parameter 

Mean 

Variance 

3rd Moment 

4th Moment 

Skewness 

Kurtosis 

Slope 

Intercept 

Coefficient of Determination 

99% Confidence Limits 

Correction Factor 

Ari themtic 

Normal 

Logarithmic 

Normal 

3 Parameter 

Logarithmic 
DRAFT 

-- 95 Percent -- tonf i dence Limit .--- -Be 

0 

Regression Line Q 

0 

e 

95 Percent Confidence Limit -- -3 -- ----- 

1 o5 1 o6 

Production Rate (MWH) 

FIGURE V- 10 ; Recirculating Cooling Water Use vs. Annual 

Production Rate 
DRAFT 

The results of the statistical analysis suggest no correlation 

at all between water use for recirculating condenser cooling 

and production rate. This is indicated by the low value 

calculated for the coefficient of determination. This 

analysis indicates that recirculating cooling water use is 

independent of plant size. 

Raw Waste Load 

The raw wastes from the recirculating condenser cooling 

process include: 

o Chemical additives to control growth organisms 

such as algae, fungi, and slimes; 

o Chemical additives to inhibit corrosion; and 

Concentrations of s o l i d s , metal 1 i c sa1 ts, 

and acidic and alkaline ions due to 

evaporative loss. 

Initially, all of these wastes are waterborne, but some, 

such as suspended solids and metallic salts settle and 

must be removed from cooling tower basins periodically. 

Also, the settling of metallic salts cause scale formation 

on condenser tubes and must be removed periodically usually 

with an acid solution. The remainder of the raw wastes 

are either removed from the wastewater by treatment 

technologies, or are discharged to the sewer systems. 

Waterborne wastes are shown in Table V-3 for plants 8392 

8135, 8696, and 7308. The waterborne raw waste values 

indicate that the major components in recirculating 

condenser cooling streams are dissolved and total solids, 

and chemical oxygen demand. 

Wastewater Treatment 

None of the plants using once-through condenser cooling 

systems discharge to POTW's. Eleven plants using 

recirculating condenser cooling systems discharge cooling 

tower blowdown to the POTW. None of the eleven plants 

discharging recirculating condenser cooling wastewaters to 

POTW's employed any treatment technologies. Wastes were 

discharged directly to the POTW without treatment. 
Table V-3. RAW WASTE FLOWS AND LOADINGS CONDENSER-COOLING SYSTEMS 

YASTFUATER SOURCE Cooling Tower Cooling Tower Cool4 ng Tower Cool 1 ng Tower Cooling Tower Cooling Tower R- B 1 owdown Blowdown Blowdown Blowdown 

FLOU L/O~Y L/HWH L /uaY LIMWH L/Day LIMWH L/Day L/MWH LIUA~ 

0 745.81 53959.0 321.51 217788.9 18.03 LKy I L'MWH (1 1 . 365.4 555.37 ' 1067370.0 1292.2 

L/MWH 

PARAYETER nu/ 1 mg/l ~ng/ I 

Cyanide (Total) 

( Prosph2:e (Total) -- 

l~otal Cissolved Solids 

Total jdspended Solids 

(1) Flow could not be measured. 
DRAFT 

Effluent Waste Loads 

Information was not obtained on the composition of 

recirculating condenser cooling wastes after treatment since 

no plants performed any treatment before discharge to the 

POTW. Waterborne wastes present in the recirculating 

condenser cooling discharge to the POTW can be found in 

Table V-3. 

WATER TREATMENT 

To compensate for steam losses through leakage and boiler 

blowdown, additional water must be added to the boiler. 

Particularly in high-pressure boilers; this water must be 

of extremely high quality, and must undergo extensive 

pretreatment. If the water is taken from a municipal 

supply, pretreatment may consist of dual media filtration, 

reverse osmosis filtration, and demineralization. Older, 

low-pressure steam plants may pretreat boiler makeup water 

solely with evaporators. Some steam electric plants treat 

water by clarification and softening followed by 

demineralization. A more detailed description of those 

treatment schemes and their associated wastes follows. 

Clarification is a process for removing suspended solids 

and dissolved impurities. Chemical coagulants such as 

alum, ferrous sulfate, ferric sulfate, sodium aluminate, 

and polyelectrolytes are added to the water to aid the 

agglomeration of these impurities into larger, heavier 

particles. The particles are allowed to settle, and the 

clarified water is drawn off and filtered. Softening 

may be performed prior to clarification to precipitate 

calcium and magnesium. Clarification and softening wastes 

consist of sludges and filter washes. Clarifier sludges 

consists of either alum or iron salts, and softening sludges 

consist of calcium carbonate and magnesium hydroxides. 

Filter washes contain suspended solids either carried over 

from the clarifier or contained naturally in the unclarified 

water. 

Demineralization (ion exchange) is a process that removes 

mineral salts by adsorption on a resin. Two types of 

resins exist: cationic (for the removal of cations), and 

anionic (for the removal of anions). These resins may be 

used separately, (one following the other), or they may be 

combined in a mixed-bed (demineralizer). After a period 

of use, ion exchange resins become saturated with adsorbed 

ions, and must be regenerated. Anionic resins are regenerated 
DRAFT 

with sodium hydroxide solution followed by water rinse to 

remove residual alkalinity. The regeneration waste will have 

a high pH and will contain the adsorbed anions, which are: 

sulfate, chloride, nitrate, phosphate, carbonate, and 

bicarbonate. Cationic resins are regenerated with sulfuric 

acid, and the regeneration waste from those units will have 

a low pH and will contain calcium, magnesium, potassium, and 

sodium ions. 

Evaporation is simply a distillation process for the 

removal of dissolved impurities. Evaporators consist of 

a horizontal vessel heated by a waste heat source, which 

is usually exhaust steam from the turbines. Steam from 

the evaporation of water in the vessel is drawn off and 

condensed in an external condenser. To prevent a 

concentration buildup of salts which contribute to scaling 

problems within the vessel, a portion of the water is drawn 

off as blowdown intermittently. This blowdown has a high 

pH, and contains the same chemicals present in the raw water 

feed, which have been concentrated by a factor of three to 

five. Calcium carbonate and calcium sulfate precipitates 

may also be present in the blowdown if present in the water 

feed in sufficiently high concentrations. Phosphate is 

sometimes added to the raw water feed to lessen the 

precipitation of calcium salts (14). 

Reverse osmosis is a process used by some plants to remove 

dissolved salts. The technique consists of forcing water 

through a semipermeable membrane under a pressure greater 

than the osmotic pressure of the dissolved salts. The salts 

are concentrated on one side of the membrane and the purified 

water is collected on the other. The concentrated salt 

solution (brine) is discharged as a waste. 

Chemical Additions. After pretreatment, various chemicals 

are added to the boiler makeup water. These include 

hydrazine sulfite (to remove dissolved oxygen), sodium 

phosphate (to prevent scale formation by precipitating 

calcium and magnesium salts), and sodium hydroxide (to 

control pH). 

Figure V-11 shows six (6) commonly used water treatment 

methods. 
DRAFT 

Raw Water I 

Deionized ~ater -+ 

Separated-Bed Ion Exchange Dembineralizer 

Raw Water 

Mixed-Bed Ion Exchange Demineralizer 

i Regulating 

Valve 

Conce trate (Wastewater) 

Reverse Osmosis Membrane Filter 

FIGURE 11. Commonly Used Water Treatment Methods 

V-25 
DRAFT 

Raw Water 

h I rt"l Wastewater + ISa1td-J r+Asy-l water Fi 1 tered 1 -I++ 

De i on 

Blowdown Water Wastewater 

i zed 

Coagulation-Filtration Water Treatment Process 

Treatment 

Chemicals 

CLARIFIER 

- I 

Feed 

Clarification Process 

Bloudown 

FIGURE 11. Commonly Used Water Treatment Methods 

(Continued) 

V-26 

- 

EVAPORATOR 

Steam 

Aond. 

I i # Evaporator 

Bloacow 

f 

Evaporation Process 
DRAFT 

Water Use 

Boiler Makeup Water. Sixteen of the twenty-two plants 

surveyed provided information on their boiler makeup 

water usage. The water use in liters per MWH at the 

plants studied is given below. 

Plant No. Water Usage Liters/MWH 

Figure V-12 is a plot of the boiler makeup water usage, 

corrected to fit normal distribution, against the cumulative 

percent of involved plants expressed as probits. The 

statistical approach used is described in Appendix A of 

this report. The coefficient of determination calculated 

by the three parameter mode of normal distribution, which 

measures the "goodness of fit" of the regression line to 

the correlated data, indicates an almost perfect fit to 

the normal distribution. The value indicates that the 

least squares straight line accounts for appoximately 

97 percent of the data variance. (See Table V-4). 
DRAFT 

5.0 6.0 7.0 

PROBITS 

FIGURE V- 12 . Normal Distribution Diagram for Normalized 

Boiler Makeup Water Usage Data 
Table V-4. STATISTICAL PARAMETERS FOR THE THREE MODES OF 

NORMAL DISTRIBUTION-BOILER MAKEUP 

Mode of Normal 

,Statistical 

Parameters 

-Mean 

Variance 

3rd Moment 

4th Moment 

Skewness 

Kurtosis 

$1 ope 

Intercept 

Coefficient of Determination 

99% Confidence Limits 

Correction Factor 

Arithmetic I Logarithmic 

Normal Normal 

3 Parameter 

Logarithmic 
DRAFT 

The water usage data was also plotted on log-log paper 

versus the production rate to determine the effect of the 

plant size on the qtantity of water used. Figure V--13 

shows the plotted dataithe regression line,and the 95 

percent confidence limits. The statistical regression 

analysis coefficients expressed as logarithms are given 

be1 ow: 

Statistical Parameters Value 

Slope -0.92 

Intercept 7.1 

Coefficient of Determination 0.47 

Standard error of estimated 

water use on production rate 0.57 

Standard error of intercept 1.45 

Standard error of slope 0.26 

The results of the statistical analyses suggest a fair 

correlation between water use for boiler makeup and 

production rate. This is indicated by the value calculated 

for the ccefficient of determination which indicates that 

the least squares regression line accounts for approximately 

50 percent of the data variance. 

Demineralizx. Thirteen of the twenty-two plants surveyed 

presented information on their demineralizer system water 

usage. The water usage in liters per MWH at the plants 

studied is given below: 

Plant No. Water Usage,Liters/MWH 

65.75 

17.51 

27.55 

3.24~102 - 

4.56 

18.38 

13.46 

4.22~102 

7.1 

9.01 

11.35 

39.23 

5.69 
1 o5 1 o6 

Production Rate (MWH) 

FIGURE V-13 . Boiler Makeup Water Use vs. Annual Production 

Rate 
DRAFT 

Figure V-14 is a plot of the demineralizer water use, corrected 

to fit normal distribution, against the cumulative percent 

of involved plants expressed as probits. The statistical 

parameters for the three modes of normal distribution 

examined are listed in Table V-5. The statistical approach 

used is described in Appendix A of this report. The 

coefficient of determination calculated by the three 

parameters mode of normal distribution, which measures the 

"goodness of fit" of the regression line to the corrected 

data, indicates an almost perfect fit to normal distribution. 

This value indicates that the least squares straight line 

accounts for 97 percent of the data variance. 

The water usage data was also plotted on log-log paper 

versus the production rate to determine the effect of 

plant size on the quantity of water used. Figure V-15 

shows the plotted data, the regression line, and the 90 

percent confidence 1 imi ts. The statistical regression 

coefficients expressed as logarithms are given below. 

Statistical Parameters Value 

Slope 0.03 

Intercept 1.52 

Coefficient of Determination 0.00 

Standard error of estimated 

water use on production rate 0.65 

Standard error of intercept 1.76 

Standard error of slope 0.31 

The results of the statistical analysis suggest no correlation 

at all between water use for the demineralizer system and the 

production rate. This is indicated by the value calculated 

for the coefficient of determination which indicates that 

a least squares regression line accounts for zero percent of 

the data variance. From this analysis, it may be assumed 

that demineralizer water use is independent of plant size. 
DRAFT 

3.0 4.0 5.0 6.0 7.0 

PROBITS 

FIGURE V-14. Normal Distribution Diagram for Normalized 

Ion Exchange Water Usage Data 
TABLE V-5. STATISTICAL PARAMETERS FOR THE THREE MODES 

OF NORMAL DISTRIBUTION - DEMINERALIZER 

Mean 

Variance 

3rd Moment 

4th Moment 

Skewness 

Kurtosis 

Slope 

Intercept 

Coefficient of Determinatio! 

99% Confidence Limits 

Correction Factor 
DRAFT 

90 Percent Confidence Limit 

--------- a,------------ 

Regression Line 

a 0 

90 Percent Confidence Limit - - - - 

------ --------- 

1 o4 1 o5 1 o6 lo7 

Production Rate (MWH) 

FIGURE V-15. Demineralizer Water Usage vs. Annual Production 

Rate 

v-35 
DRAFT 

Raw Waste Load 

The raw wastes from the water treatment process include: 

o Mineral salts, suspended sol ids and other 

constituents removed from the raw water 

supply. 

Chemicals used by the water treatment units. 

Of the twenty-two plants visited, three use hot lime-soda 

ash softening and zeolite ion exchange, two use hot 

lime-soda ash softening, filtration, and zeolite ion 

exchange, two use reverse osmosis and deionization, 

twelve use cation-anion ion exchange, one uses 

deionization and evaporation, one uses hot lime-soda 

ash softening, zeolite ion exchange and evaporation, and 

one uses deionization and evaporation. 

Solid wastes are not generated in large quantitites during 

the water treatment process. The major source of solid 

wastes are calcium carbonate and magnesium hydroxide from 

the lime-soda ash softening processes. Waterborne wastes 

for plants in terms of grams per MWH are given in 

Table V-6. 

Wastewater Treatment 

Fifteen plants discharge water treatment waste streams to 

POTW's. Five of these plants practice some type of 

pretreatment before discharge. Plant 6293 uses lime 

settling; plant 9369 uses equalization and neutralization; 

plant 7308 uses equalization, neutralization, and settling; 

and plant 8696 uses equalization, settling, and oil skimming. 

Effluent Waste Loads 

Table V-7 shows the composition of pretreated wastewater 

discharge to the POTW in terms of concentration and 

waste loads for plant 6293. 

BOILER BLOWDOWN 

To prevent the accumulation of calcium and magnesium salts 

on the internal boiler surfaces, phosphates are usually 

added to precipitate the salts. The precipitate is removed 

continuously or intermittently by withdrawing a portion of 

the boiler water as blowdown. Blowdown wastes have a high 
Table '1-6. RAW WASTE FLOWS AND LOADINGS - WATER TREATMENT 

(I) Flow could not be measured. 

0 

;O 

D 

7 

--I 

PLANT 10. 

;ASTEYLT~~ SO,,~CE z2"'8.13 iLou 

CR 

COO5 

Bromide (8romrte) 

COO 

Chromium 

~hramiua'6 

topper 

Cyanide (Total) 

Iron 

LllckCl 

011 arid Grease 

Phosphate (Total) 

lotrl Oissolved Sollds 

lotal Suspended Soll#s 

lolrl Sollds 

Surfrctrntr , 

tlnc 

6387 6187'~ 

LIme Softener Zeollte 

(slug 

/Day Tho 

W/' 

10 4 

561 

0.1 

0.001 

0.12 

0.005 

0.44 

0.25 

1 .O 

22980 

44 

23024 

------ 0.09 

Backwash 

.d Y 18.7 

"911 

1.8 

--- 

ZOO 

0.11 

0.004 

0.15 

0.014 

10 4 

0.09 

10 

1004 

9440 

10444 

- - - - 

0.32 

8392 

Oemineallzer Backwash 

2:": 

g/MUH 

2.62 

141.55 

0.02 

0.001 

0.03 

0,0011 

0.11 

0.06 

5798.6 

11.1 

5809.7 

0.02 

% 

glHUH 

0.08 

----- 

9.53 

0.005 

0.007 

0.0006 

0.49 

0.004 

47.88 

450.2 

98.08 

0.015 

(process 

Nb/: 

1.0 

1.02 

2 0 

0.02 

0.005 

0.02 

0.005 

0 07 

0.03 

1.0 

0.05 

174 

1 0 

- 174 

-- 0.011 

0.02 

6387 8231 I 

fvaporator Olowdown Oalnersllzer 

water) Reopneration 

9:M)Uh 

. 

- - - 

6293 

1f.e Softener 

9650 - Cdined Ceminerallzer Fffl~.rnr 

L/Da# LI'YV 

8231 

Demlnerallzer Bactwash 

81 35 

Oemineallzer 

L/O4y 

m91 1 

48.0 

...- 

37.2 

0.09 

0.006 

0.06 

0.005 

9.0 

0.07 

1.0 

-.- 

188 

1780 

1968 

0.010 - 

0.12 

5103 75 

roll 

------ 

----a- 

------ - 

0 2 

0 01 

0.59 

.----- 

9.46 

0.2 

10 

------ 

------ 

16.7 

-------. 

-- -------- 

0.21 

tii;i 

D9/l 

15.2 

76.0 

0.02 

OW kl73.8 

n411 

----- 

----- 

----- 

0.02 

0.005 

0 02 

----- 

0.03 

0 03 

8.2 

-- - - - - - - - - - - 

6.8 

- .---- 

0.38 

0.01 

Effluent 

:{:;I5 

"911 

1.0 

1.19 

9 8. 

0.02 

0.002 

0.02 

0.005 

0.02 

0.03 

1.0 

---- 

0.16 

---- 

0.16 

---- 

---- 

L/WH 

9/,4~n 

3.27 

-...- 

2.53 

0.006 

0.004 

0.6 

0.004 

---- 

12.8 

121.27 

134.08 

- 

0.001 

0.008 

61 a 

C/HL 

------ 

------ 

------ 

0.31 

0 Ci.r 

o 03 

------. 

0 5e 

0 01 

. -- . . - . 

- - . - - - . 

- - - - - - - 

I .03 

------- 

------. 

0 01 

11:!:27$;$ 

(1M.H 

1.72 

8.62 

LIIWH 2.46 

gIWH 

----- 

----- 

----- 

- - -- - 

----- 

----- 

------ 

------ 

------ 

0.02 

- - - - - - - - - -- - 

0.016 

--.--- 

0,0009 

------ 

wjll 

-- 

- - - - - ----- 

0.07 

'in:! 

g/UUH 

0.003 

0.004 

0.03 

----- 

----- 

----- 

----- 

----- 

----- 

----- 

0.05 

174 

1.0 

114 

0.011 

0.02 

0.005 

0.02 

0.006 

0.38 

0.03 

1 .0 

6.20 

2228 

9 3 

2321 

0.11 

21.73 L'INH 

g/WH 

-.... 

- - - - - ----- 

0.001 

0,0001 

------ 

------ 

0.02 

0 003 

0.28 

.--.. 

----- 

0.63 

-.--. 

---- ----- 

0.001 

0.050' 

o 002 

0.OOOt 

0.043 

0.7 

252.9 

105.6 

263.5 

0.01 

0.006 

0.02 

----- 

1.26 

0 14 

13.2 

....- 

----- 

31 

-.--- 

-.--- 

0.06 
DRAFT 

Table V-6. RAW WASTE FLOWS AND LOADINGS - WATER TREATMENT 

(CONTINUED) 

IPLANT NO. 1 8696 (7308 1 7308 

 WASTEWATER SOURCE 1 cation Demin- Evaporator 

era1 i zer Bl owdown I Sof~~~~~t~ackw\~eqeneration 

L/Day L/MWH 

PARAMETER \11355(2) 0.94 

mq/l q/MWH 

BOD, 6.0 0.005 

Bromide (Bromate) 

I I 

Copper 1 1.3 o.ooi72.61 0.13 N c g 1 

LIDay L/MWH 

(1) (1) 

mg/l g/MWH 

5.16 (1) 

Chromi um (Total) 

~hromi um+6 

Wash 

L/Day L/MWH 

4920.5(2) 0.29 

mg/l 9/MWH 

27 0.008 

0.03 0.00002 

10i 1 and Grease ] <1 .0 11.9 1 1.4 0.0004 1 

0.07 0.00006 

0.008 Neg. 

Cyanide (Total) 

Iron 

l~hosphate (Total) / 14.0 0.013 112.6 1 0.5 0.0001 1 

---- 0.07 N e !3 

0.08 

0.036 

c0.005 

1.02 0.009 

CO .02 ----- 

0.016 Neg 

Total Dissolved 

Sol ids 

0.028 

0.22 

Total Suspended 

. Solids 

Total Solids 

(1) Flow could not be measured 

(2) Discharges 1 hour per day 

(0.005 - - - - - 

40.57 ----- 

3960 3.72 

Zinc 

3 0 0.03 

3990 3.75 

I 

. - 

0.03 0.00002 

2532.66 

14.5 

2547.16 

28066 8.21 

18.4 Oi005 

- 

28084.4 8.22 

0.44 0.08 0.00002 
Table V-7. EFFLUENT FLOWS AND LOADINGS - WATER TREATMENT 

PLANT NO. 1 6293 I 8696 1 8237 

I I I I I I 

Bromide (Bromate) I ----- I ----- ---- I 

WASTEWATER SOURCE 

FLOW 

PARAMETER 

I I I 1 I I 

Iron I 1 .23 1 0.08 I 3.0 I 0.01 10.85 ( 0.020 

I 1 

Lime Softener s Effluent 

COO 

Chromi urn 

Chromium+6 

Copper 

Cyanide (Total) 

L/W L/MWH 

16351.7 68.13 

5.9 

0.02 

Nickel P 0.03 

Oil and Grease 1 .O 

Phos~hate (Total) ------- 

LIDay L/MWH 

54504 4.57 

.-, I 1 1 I I I 

Effluent 

LIOay L/MWH 

15518.5 14.85 

mg/l I 9fRWH 1 mgll I 9/MWH 

0.4 

0.001 

Total Dissolved Solids I 152.0 

Total Suspended Solids 

Total Solids 

Surfactants 

Zinc 

mg/l I g/c 

0.001 

0.13 

------- 

I I I 

10.35 I 954 I 

0.026 

0.02 

0.005 

- - - - - ----- 

------ 

245.0 

397 .O 

-- 

0.011 

0.2 

------ 

0.0007 

I I 

0.001 

0.001 

----- 

0.0001 

81 .O 

0.05 

40. 005 

16.69 

27.04 

0.0001 

0.0001 

0.09 

9.36 

------- 

(0.03 

1.80 

---- 

0.88 

(0.005 

0.36 

0.002 

------- 

-------. 

0.008 

-------. 

21 9 

1173 

------ 

0.18 

------ 

-- ---- - 

0.05 

0.007 

0.98 

5-26 

------- 

0.0008 

25.02 0.35 

- ------ 

------- 

0.04 

----- -- 

------- 

0 .0005 
DRAFT 

pH and a high dissolved solids concentration. Blowdown 

from boilers treated with phosphate will contain hydroxide 

alkalinity and phosphate, and blowdown from boilers treated 

with hydrazine will contain ammonia. 

Raw Waste Load 

The raw wastes from boiler blowdown include: 

Chemical additives to remove oxygen; 

e Chemical additives to prevent scale or 

inhi bit corrosion; and 

e Concentrations of dissolved solids and 

other constitutents present in the 

boiler feedwater. 

Boiler blowdown does not generate large quantities of 

sol id waste. Sludge, which consists of precipitated 

calcium and magnesium salts, is maintained in a fluid 

form and removed by the blowdown. 

Waterborne wastes for two plants in terms of grams per MWH 

are given in Table V-8. 

The waterborne raw waste values indicate that the major 

components by weight in boiler blowdown streams are 

dissolved solids, chemical oxygen demand, and total 

phosphates. 

Wastewater Treatment 

irteen plants discharge boiler blowdown to POTW's, of 

ich, three practice some type of pretreatment. Plant 9369 

es equalization and neutralization, plant 7116 uses 

ualization, neutralization and settling and plant 7308 

es equalization, neutralization and oil skimming. 

Effluent Waste Loads 

Information was not available on treated waste streams from 

boi 1 er blowdown. 
Table V- 8 . RAW WASTE FLOWS AND LOADINGS - BOILER BLOWDOWN 

PLANT NO. 6293 8392 8231 9650 

WASTEWATER SOURCE Boiler Blowdown Boi 1 er Blowdown Boi ler Blowdown Boiler Blowdown 

I I I : 1 

FLOW L/DAY L/MWH- L/OAY LIMWH L/DAY LIMWH L/DAY 1 L/MWH 

17030.4 70.96 1665.4 5.20 5715 5.47- 0~ 1 

PARAMETER 9/MWH mg/l mg/1 g/MWH mg/ 1 g/MWH mg/l I I I 

Bromide (Bromate) ---- ------ ----- ---- - - - - ------ ----me ----- 

COD 157.0 11.1 2.0 ---- ----- ------ ------ ----- I I I I I I I I 

Chromium (Total) 1 0.02 ------- 1 0.02 1 0.0001 1 0.02 ----- I 1 I I 

Chrcmi um+6 I 0.007 Neg . 0.005 ----- I I I 

Copper 1 -0.19 ( 0.01 1 0.06 I I 

Cyanide (Total ) 0.005 ------- 0.014 Neg . ----- - - - - - - ------ - - - - - - 

Iron 1.4 0.1 0.08 0.0004 0.03 0.03 ------ 

Nickel 0.03 ------ 0.03 ------ 0.03 ------ 0.03 ------ 

Oil and Grease 2.2 0.15 1 .O ------ 14.8 0.08 5.3 ------ - - - 

Phosphate (Total) 18.7 1.32 19.8 0.1 0.05 

Total Dissolved Solids 1405.0 99.7 118.0 0.61 ----- ------ ----- ------ 

Total Suspended Solids 2.7 0.19 6.9 0.036 3 1 0.17 8.3 ------ 

Total Solids 1407.7 99.9 125.0 0.65 ----- _______ ----- - - - - - - 

Surfactants - - - - - - ----- ----- ------ ----- ------- ------ - - - - - - 

Zinc 0.05 0.003 0.02 0.0001 0.01 ------- 0.02 Neg . -- - -- - - 

(1) Flow could not be measured. 
DRAFT 

MAINTENANCE CLEANING 

Boiler Tubes. Boiler tubes must be cleaned occasionally 

to remove accumulations of scale. A multitude of cleaning 

mixtures are used to accomplish this purpose with a 

minimum of effort. These include: alkaline cleaning 

mixtures with oxidizing agents for copper removal, acid 

cleaning mixtures, alkaline chelating rinses, organic 

sol vents, and proprietary solvents. Wastes from these 

cleaning operations will contain iron, copper, hardness, 

and phosphates. In addition to these constituents, wastes 

from a1 kaline cleaning mixtures will contain ammoni um 

ions, oxidizing agents, and high alkalinity; wastes from 

acid cleaning mixtures will contain fluorides, high 

acidity, and organic compounds; wastes from alkaline 

chelating rinses will contain high alkalinity and organic 

compounds; and wastes from most proprietary processes will 

be alkaline and will contain organic and ammonium compounds. 

Boiler Fireside Cleaning. The fireside surface of boiler 

tubes collects airborne dust, fuel ash, and corrosion 

products. These materials are removed from time to time 

with high-pressure hoses. Alkaline chemicals may be used 

to make the cleaning more effective. 

Wastes from this operation will be more or less acidic 

depending on the sulfur content of the fuel, and will 

contain hardness, suspended solids, and some metals. 

Air Preheater Cleaning. Air preheaters are used to heat 

ambient air that is used for combustion, and collect soot 

and fly ash. High-pressure hoses are used to remove these 

materials. The wastes from this operation will be more 

or less acidic, depending on the sulfur content of the fuel, 

and will contain suspended solids, magnesium salts, iron, 

copper, nickel, and chromium. Vanadium may also be present 

if the plant is oil-fired. 

Stack Cleaning. High pressure water is used to clean fly 

ash and soot from stacks. The frequency that this 

cleaning is required is dictated by the- fossil fuel used. 

Wastes from this operation may contain suspended solids, 

metals, oil, and high or low pH values. 
DRAFT 

Cooling Tower Basin Cleaning. Deposits of carbonates on 

the bottoms of cooling towers and growth of algae on 

cool ing towers are removed occasionally with water. The 

wastes contain suspended solids as a primary pollutant. 

Miscellaneous Small Equipment. Occasional cleaning of 

plant equipment such as condensate coolers, hydrogen 

coolers, air compressor coolers, and stator oil coolers 

is performed. Detergents, wetting agents, and hydrochloric 

acid are often used during cleaning. Wastes from these 

operations will contain suspended solids, metals, oil, and 

low or high pH. 

Raw Waste Load 

The raw wastes from maintenance cleaning consist of the 

cleaning solution and the material removed from the 

equipment. Boiler fireside, air preheater, and boiler tube 

cleaning account for most of the wastewater generated in 

maintenance cleaning. No plants were performing maintenance 

cleaning during the time of our visitation and sampling. 

Typical waterborne wastes are shown in Table V-9 for 

wastewaters from air preheater boiler fireside, and tube 

cleaning. This information was obtained from Reference 14. 

Information was not available on cooling tower basin and 

stack cleaning wastewaters. 

The major components by weight in the three cleaning waste 

streams are dissolved solids, hardness, metals, chlorides 

and sulfates. 

Water Use 

At infrequent intervals, certain power plantscomponents such 

as condensate coolers , oi 1 coolers , compressors, boi 1 ers , etc. are chemically cleaned with a solution of hydrochloric 

acid, or a detergent. Typical flow rates are summarized 

on page V-45 (14). 
DRAFT 

Table V-9. RAW WASTE FLOWS AND LOADINGS - MAINTENANCE CLEANING 

I No. of Plants 

Wastewater Source 

Cleaning Frequency 

1 Parameter (Kg) 

I Bromide (Bromate) 

C 0 D 

Chromium (Total) 

Chromi um 

Cyanide (Total ) 

I Iron 

I Nickel 

I Oil and Grease 

I Phosphate (Total) 

Total Dissolved 

Sol ids 

Total Suspended 

Solids 

Total Solids 

Surfactants 

I Zinc 

7 plants I 2 plants I 7 olants 

Air Preheater Boiler Fireside 1 Boiler Tubes 

I I 
DRAFT 

Waste Waste Typical Flow 

Stream Flow or Volume Frequency or Volume 

Chemical Cleaning 

Boiler Tubes 3-5 Boiler Once/7 Months- 1 boiler per 

Vol umes once/100 mos. 1-2 hours 

Boiler Fire- 24-720~10~~al 2-8/yr 300,000 Gal 

side 

3 Air Preheater 43-600x10 gal 4-12/yr 200,000 Gal 

Wastewater Treatment 

Four plants discharge maintenance cleaning wastewaters to 

POTW's of which two utilize some type of pretreatment 

Plant 6387 uses settling and plant 8696 uses dilution, 

equalization, settling and oil skimming. Three plants 

have outside contractors haul away boiler cleaning wastes. 

Effluent Waste Loads 

Information was not obtained on the composition of 

maintenance cleaning wastes after treatment. 
DRAFT 

ASH-HANDLING SYSTEMS 

One of the products of the combustion of coal and oil in 

electric utilities is ash. Ash which falls to the bottom 

of the furnace is called bottom ash; ash which leaves the 

furnace with the flue gas is called fly ash. Fly ash is 

usually collected from coal-fired units with electrostatic 

precipitators and from large oil-fired units with cyclones. 

The function of ash-handling systems is to remove accumulated 

bottom ash and fly ash. 

Two types of ash-handling systems exist: dry systems and wet 

systems. Dry systems use pneumatic conveyance devices for 

the transport of ash and are not a source of liquid wastes.. 

Wet systems use water for the transport of ash, transporting 

the ash-water slurry through sluices and in many cases, 

discharging it into a settling pond or basin. 

Wet systems are either of the open type or the closed type. 

Open systems discharge supernatant from the settling basin 

into either a receiving water or a POTW. Closed streams 

recycle the supernatent back to the ash-transporting sluice 

for reuse. Figure V-16 shows a flow diagram for recirculating 

bottom ash system. Periods of extended rainfall may cause 

problems with closed systems, since some water may have to 

be withdrawn from the settling basin and discharged. Similarly, 

extended periods of dryness may evaporate excessive amounts 

of water from the settling basin, requiring the addition of 

supplementary water to the system. 

Ash pond overflows from coal-fired plants contain a wide 

variety of constitents whose concentrations can vary widely 

depending on the particular coal used. Generally, the 

overflows contain high levels of dissolved solids, suspended 

solids, hardness, sulfate, sodium, magnesium, chloride, and 

alkalinity. Other trace metals originally present in the 

coal may also be present. 

Ash is produc.ed in oil-fired plants in very small quanitities. 

It has been found that oil ash does not settle as well as 

coal ash. In some utilities, the oil fly ash is recycled 

into the furnace, increasing efficiency and eliminating the 

disposal problem. Ash pond overflows from o i l - f i r e d plants 

have some of the same characteristics as those from coalfired plants, and may additionally contain high concentrations 

of vanadium. 

Table V-10 contains an itemization of the types of ash 

handling systems used by the plants that were visited. 
DRAFT 

EVAPORATION 

EVAPUKA l LUN LU33 LU33 MHKL-UI-' 

ASH HANDLING 

SYSTEM 

ASH SLUDGE FOR 

DISPOSAL 

RAINFALL 

. 

FIGURE V-16. Flow Diagram for Recirculating Bottom 

Ash System 

+ 

RECYC 

. 

OVERFLO 

SETTLING POND 
Table V-10. ASH DISPOSAL METHODS 

r 

PLANT NO. 

9600 

9650 

Key: (1) Soot blowing steam 

(2) Fireside washing 

(3) Dry collection system from electrostatic and/or mechanical precipitators, ash then hauled to landfi 11.. 

(4) Dry collection sy-stem-ash landfil led. 

(5) Air wash in stack to control fly ash-discharges to 

POTW 

(6) Wet collection system with settling sump-(overflow 

from sump' goes to POTW) 

(7) Vacuum system using steam, ash landfilled, condensate 

from steam goes to POTW. 

(8) Wet system discharging to surface water. : 

TYPE OF PLANT 

< 

I 

P 

O3 

ASH DISPOSAL SYSTEM 

FLY ASH BOTTOM AS'H . - 

Oil and Gas 

Oil and Gas 

None Required 

1 2 

-9359 

,9371 

7485 

,881 6 

,9585 

.7116 

-8696 

,8135 

,9163 

6387 

-8352 

6293 

,7 308 

,8875 

7968 

6421 

16214 

6294 

Oil and Gas 

Oil and Gas 

Coal , Oi 1, and Gas 

Oil and Gas 

Gas 

Oil and Gas 

Oil and Gas 

Oil and Gas 

Coal 

Coal 

Gas 

Coal 

Oi 1 

Oil and Gas 

Coal and Gas 

Oil and Gas 

Coa 1 

Coal and Gas 

3 4 

3 2 

3 4 

1 2 

None Requi red 

3 4 

3 2 

None Required 

3,5 4 

3 6 

None Resui red 

3 7 

None Required 

1 2 

3 7 

None Required 

8 8 

3 8 
DRAFT 

Mater 5 

Of the twenty-two plants visited in this study, only 

four used water to convey fly and bottom ash to 

ash ponds; the remaining plants use dry ash transport 

systems. Of the four plants utilizing wet systems, all 

were coal-fired. Plant 9163 uses 2.65~102 liters per 

MWH, the only plant using water for fly ash transport. 

The other three plants 6387, 8356, and 6294, respectively 

use 43.09, 3.61~102 - and 11.39 liters per MWH for bottom 

ash transport. 

- Raw Waste Load 

Oil-Fired Plants. Fuel oils contain only about one percent 

of the amount of ash commonly found in coal, consequently, 

ash disposal problems from oil-fired plants are minimal. 

Fly Ash. Many of the oil-fired plants visited used 

mechanical cyclones to remove fly ash from the flue gases. 

A dry system is usually used to remove the collected ash. 

In other plants, no fly ash collection system is necessary 

because of the low ash content of the oil used. In these 

plants, most of the ash in the flue gases collects on the 

interior surfaces of the boiler and is removed by high 

pressure steam (soot blowing steam), and passes through the 

stack to the atmosphere. 

Bottom 3. Some of the oil-fired plants visited needed only 

occasional fireside washing to remove bottom ash, other 

plants had dry collection systems that removed ash for 

land disposal. 

Coal-Fired Plants. The amount of ash produced by coalfired plants is much greater than that produced by oilfired plants, requiring the use of m o r e ' c o m p l e x ash-hand1 ing 

systems. 

Fly Ash. Electrostatic precipitators or mechanical cyclones 

are used in most of the coal-fired plants to collect fly 

ash. The collection systems from these units are usually 

dry, and the final ash disposal is on land. One plant, 

No. 9163, used an additional system for fly ash control, 

consisting of a wash in the stack that discharged excess 

fly ash to a POTW. 
DRAFT 

Bottom Ash. Methods for disposing of bottom ash varied 

widely among the coal-fired plants that were visited. 

Plants 7485 and 9163 used dry collection systems 

for the land disposal of bottom ash. Plant 6387 was the 

only plant visited that used a wet transport system in 

combination with a settling sump. Two plants No. 6293 

and 7628 used a vacuum collection system with steam. One 

plant, No. 6294, used a wet collection system discharging 

to surface water. Plant No. 6214 mixed both bottom 

ash and fly ash with once-through cooling water. 

Table V-11 shows raw waste loading for two plants, 

6293 and 6387. 

Wastewater Treatment 

Oil-Fired Plants. Because of the small quantities of ash 

produced by oil-fired plants, none of the visited plants 

had ash treatment systems. 

Coal-Fired Plants. Only one plant, No. 6387, used a 

settling basin in conjunction with a wet ash transport 

system.- Most of the other coal-fired plants had no 

need for an ash treatment system, since these plants used 

dry collection systems, followed by land disposal. 

Effluent Waste Loads 

Oil-Fired Plants. Effluents from ash cleaning of oilfired plants are present for those plants which used fireside 

cleaning for ash removal. 

Coal-Fired Plants. Plant No. 6387 is the only visited plant 

that discharqed a siqnificant amount of waste 

from an ash handling-system to a POTW. The discharge 

consists of the overflow from the ash settling sump. Treated 

effluent is shown in Table V-12. 

DRAINAGE 

-- Floor - 

and - Yard Drains. Floor and yard drains collect wastes 

from leakage and numerous cleaning operations, and may 

discharge to a POTW. The waste will contain dust, fly ash, 

coal dust from coal-fired plants, oils, and detergents. 
DRAFT 

Table V-11 . RAW WASTE FLOWS AND LOADINGS - ASH HANDLING 

PLANT NO. I 6293 I 6387 

WASTEWATER SOURCE I Ash Transport I Ash Transport I 

Bromide (Bromate) 

COD 

Chromi urn 

Oil and Grease 1 1.0 1 ---- I 1 .O I ----- I 

Copper 

Cyanide (Total) 

Iron 

Nickel 

- - - 

1235.0 

0.37 

0.16 

0.005 

76.0 

0.24 

Phosphate (Total) 

Total Dissol ved 

---- 

140.23 

0.04 

0.018 

0.0005 

8.62 

0.03 

3.4 

388.0 

- - - 

290.0 

0.12 

----- 

36.58 

0.015 . 

0.20 

0.112 

6.2 

0.03 

0.38 

44.05 . Solids 

- 

0.025 

0.014 

0.78 

0.003 

129.90 

173.95 

Total Suspended 

Solids 

Total Solids 

Surfactants ------ ------ ------ 

Zinc 0.55 0.06 0.08 

0.02 

1894.0 

1144.0 

1532:o 

------- 

- 

0.01 

- - - --- - -- - - -- 

------ 

238.95 

1651 .O 

3545.0 

208.30 

447.26 
DRAFT 

PLANT NO. 

FLOW 

I PARAMETER I 

k------I

Bromide (Rromate) 

Settled ash transport 

condensate 

L/MWH 

45420 .O 126.16 

Chromi urn 

Chromium+G 

- 

Copper 

Cyanide (Total ) 

I Nickel I 

Oil and Grease 

Phosphate (Total) 

I Total Dissolved Solids I 

Total Suspended Solids 

1 Total Sol ids I I 

Surfactants I 

Zinc I 
DRAFT 

-- Coal Pile. The storage of large quantities of coal 

is necessary for coal-fired plants to insure continuous 

operation and to simplify delivery by the supplier. A 

90-day supply is normally maintained. Coal storage piles 

are of two types: active and storage. Active piles are 

used continuously and are subject to infiltration by 

rainwater. Storage piles are used for the long-term 

storage of coal, and are usually protected from rainfall 

with some sort of seal, which can be either a layer of 

asphalt or a layer of fine coal dust covered with lump 

coal. 

Waste discharges from coal storage piles are the product 

of drainage from rainfall. This drainage can be either 

acidic or alkaline. Acid drainage is the result of the 

reaction of pyrite (FeS2) with water and oxygen, which 

produces iron sulfate and sulfuric acid. This type of 

drainage is highly acidic, has a low pH, and contains a 

large amount of ferrous iron and some aluminum. Alkaline 

drainage occurs when acid drainage is neutralized by 

alkaline material present in the coal, or when the coal 

has a low pyrite content. Alkaline drainage is characterized 

by a pH of 6.5 to 7.5 or greater, little acidity, and 

significant concentrations of ferrous iron. If the ferrous 

iron concentration is high enough, the iron may precipitate 

upon oxidation and hydrolysis. 

Drainage from coal piles may contain in addition to the 

aforementioned constituents, high concentrations of 

dissolved solids and significant amounts of copper, zinc, 

and manganese. Other materials may also be present that 

are the result of the reaction of sulfuric acid with 

minerals and organic compounds present in the coal. 

Raw Waste Load 

-- Coal Pile. Almost all of the plants that were visited 

allowed coal pile drainage to drain to either the surface 

water, storm sewers, or nearby land. An exception was 

plant No. 9163, which stored all of its coal under roof, 

thus eliminating any drainage problems. 
DRAFT 

General chemical characteristics of coal pile drainage 

were discussed under the previous heading. Reference 16 

lists ranges for some of the elements present in coal 

pile drainage, which are shown below: 

El ement Concentration Range, mg/l 

Copper 

Iron 

Zinc 

Floor -- and Yard Drains. Drainage from floor and yard drains 

in most cases can be assumed to be a negligible waste source. 

Many plants exercise meticulous care, to prevent oil leaks 

and spills from reaching floor drains by using drip pans and 

oil absorbing materials. Some plants particularly those in, 

open areas or in dry regions, have no need for yard drains 

and have no drains installed. 

Reference 16 list characteristics of wastes from yard and 

floor drains, which are summarized below: 

Parameter 

BOD 

TSS 

pH 

Surfactants 

Chromium 

Lead 

Phosphorous 

Oil and Grease 

Concentration Range (mg/l) 

2-4 

0-5 

Low-Neutral 

Present 

0-20 

Present 

0-1 0 

Present 

Wastewater Treatment 

None of the plants that were visited used any type of 

coal pile drainage treatment system. 

One plant No. 7116 discharged floor drainage (along with other 

wastes) to a settling tank before discharge to a POTW. 

Other plants discharged floor and yard drainage without 

treatment either directly to surface water or to a POTW. 

Effluent Waste Loads 

Information was not available on treated wastewater before 

discharge to the POTW. 
DRAFT 

AIR POLLUTION CONTROL EQUIPMENT 

Liquid waste disposal problems associated with air pollution 

control equipment are mainly limited to systems for the 

control of S02. - Control systems for SO2 can be further 

divided into "throwaway" and "recovery" processes. Throwaway 

processes produce a sludge or cake that must be disposed 

of. Recovery processes produce either elemental sul fur, 

sulfuric acid, or gypsum, which are marketable and have no 

disposal problems. The following discussion will be limited 

to a throwaway process. 

The greatest number of existing flue gas desulfurization 

systems (including recovery and throwaway) use tail-end 

scrubbing with lime and/or limestone. Those scrubbing systems, 

installed after the boiler, remove particulates as we11 as 

sulfur dioxide by reacting the flue gas with slurries of 

lime or limestone forming calcium sulfates and sulfites. 

The calcium sulfate/sulfite sludge is usually piped to 

large settling ponds. 

A small number of existing throwaway systems are of the 

double-alkali type. In these systems, sodium or 

ammonium sulfates and sulfites are used as a scrubbing 

solution. After contacting the flue gas, the scrubbing 

solution is reacted with limestone or lime to precipitate 

calcium sulfi te and sulfate and regenerate the solution 

for recirculation to the scrubber. Scrubber wastes consist 

of a dry filter cake. 

Figure V-17 shows a flow diagram for an air pollution 

control scrubbing system. 

Water 'e 

None of the twenty-two plants visited in the study used 

water to control SOX emissions. This can be accounted for by the 

fact that the majority of the plants burned low sulfur 

(1 percent) coal or oil thereby eliminating the need for 

air pollution control devices. 

Raw Waste Load 

None of the utilities visited had flue gas desulfurization 

equipment. Since the wastes from these systems are mostly 

in the form of sludges, which are disposed of on land, no 

problems with waste discharges to POTW's are anticipated. 
DRAFT 

STACK CASES 

I I 

I I 

I I 

I I STEAM TO TURBINES 

4 I STACK CASES I 

).---- I I 

I + I . I BOILER 

I 

I 

I 

I FLUE GASES l-----J 

INLET 

SCRUBIER Lmuou 

OVt HFLOW 

CLARIFIER THICKENFH 

WATER MAKEUP 

OVERFLOkV 

SET I L IN(; 

IJNl>t ItF LOW 

FIGURE V-17. Flow Diagram For Air Pollution Control 

Scrubbing System (Ref. 14) 
DRAFT 

Wastewater Treatment 

None of the plants discharged SO& removal wastewaters to 

the POTW. 

Effluent Waste Load 

Information was not available on treated wastewater before 

discharge to the POTW. 

MISCELLANEOUS WASTE STREAMS 

Sanitary Wastes. Sanitary wastes from steam-electric plants 

are similar to municipal domestic wastes with the absence 

of laundry or kitchen wastes. The volume of waste flow is 

dependent upon the number of employees. 

Plant Laboratory Wastes. Many steam-electric plants have 

laboratories for the chemical analysis of various process 

streams within the plant. Depending on the analyses performed, 

the waste from this source will contain a large variety 

of chemicals, albeit in small amounts. 

Intake Screen Backwash. Power plants that withdraw cooling 

water from a natural body, such as a lake or river, use 

traveling screens to prevent debris from entering the intake 

system. Occasionally the debris from these screens is 

collected, and the screens are washed with hoses. 

Supplementing Cooling Water Systems. These cooling systems 

are generally maintained for such uses as bearing and gland 

cooling for pumps and fans. The systems may be oncethrough or recirculating. Chemicals are not used in oncethrough systems, except for occasional shock chlorination. 

Recirculating systems use water of high purity, supplemented 

by pretreated makeup water. Chromates, borates, and nitrates 

are used in recirculating systems to prevent scale formation. 

Construction Activity. The construction of buildings and 

equipment adjacent to power plants can cause the presence 

of additional amounts of suspended solids and turbidity 

in the storm-water runoff due to the erosion of soil 

disturbed by the construction activity. 
DRAFT 

Water - Use 

Housekeeping. Housekeeping water usage, which includes floor 

washing and sanitary water (bathrooms, sinks, etc.), amounts 

to less than one percent of the total. Only two plants of the 

twenty-two in the study had any substantial floor wash water 

usage these being plant No. 6421 with 13.08 liters per MWH 

and plant No. 6294 with 1.71 liters per MWH. The following 

table lists the water for sanitary purposes. 

Plant No. 

Miscellaneous Cooling. Miscellaneous cooling needs include 

bearing cooling water, cooling of compressors, and other 

extraneous equipment cooling needs. Water usage varied for 

six plants from a low of 1.59 liters per MWH for plant No. 

9396 to a high of 1.45~104 for plant No. 8356. Using the 

least squares analysis meThod for the normalized data, a 

coefficient of determination of 0.945 was calculated 

indicating that approximately 94 percent of the data 

variance could be accounted for by the least squares 

straight line. 
DRAFT 

Raw Waste Load 

Sanitary Wastes. Reference 14 states that the per capita 

sanitary waste load is generally 25-35 gal/day (94.5-132 

liters/day) from steam-electric power plant. The reference 

also lists the number of employees per MW that may be 

expected to be found at typical power plants: 

operational personnel : 1 per 20-40 MW 

maintenance personnel: 1 per 10-15 MW 

administrative personnel : 1 per 15-25 MW 

The flow, BOD?, and suspended solids per capita load can be 

estimated by the following (14): 

Fl ow BOD5 TSS 

Office-Administrative 0.95 cu 

(per capita) m/day 

309 

(0.071b) 

709 

(0.15 lb) 

(25 gpd) 

Plant (per capita) 0.133 cu 

m/day 

409 

(0.09 1b) 

859 

(0.19 Ib) 

(35 gpd) 

Plant Laboratory Wastes. The volume of wastes from in-plant 

laboratory can be assumed to be negligible. Reference 14 

suggests that if a toxic materials problem is found to 

originate from a laboratory drain, it may be appropriate to 

either: (1) change the test procedure, (2) contain the waste 

for separate treatment, or (3) remove the waste from the site. 

Supplementary Cooling Water Systems. Wastes are discharged 

from recirculating cooling systems during blowdown, which 

may typically be twenty liters per day with a settleable 

solids content of 1-2 ppm (14). Additional wastes are 

discharged during drainage and cleaning operations, which 

are infrequent. 

Plants which use once-through systems may discharge the 

effluent from the entire system to a POTW. This waste 

stream will probably contain chlorine, and the stream is 

usually of significant volume. 

Construction Activity and Intake Screen Backwash. The 

nature and duration of these wastes do not contribute 

significantly to the total waste load. 
DRAFT 

Wastewater Treatment 

Sanitary Wastes. Sanitary wastes are generally discharged 

directly to POTW's or septic tanks without treatment. An 

exception is plant 7116, which pretreats sanitary wastes 

(along with other wastes) in a settling tank before 

discharge to a POTW. 

Plant Laboratory Wastes. Most plants combine laboratory 

drains with other sanitary plant plumbing, and discharge 

the waste without pretreatment. 

Supplementary Cooling Water Systems. Supplementary cooling 

system wastes are usually discharged directly, although 

one plant 7116, discharged the waste to a settling tank 

before discharge to a POTW. 

Construction Activity and Intake Screen Backwash. Most 

plants do not treat these wastewaters. Intake screens are 

generally backwashed into the water source. 

Effluent Waste Loads. 

Information is not available on treated effluent from 

miscellaneous waste streams. 

-- THE POTW PROCESS 

Prel imi nary Physical Treatment 

Most POTW's employ initial physical treatment of wastewater 

for the removal of course materials, settleable sol ids, 

grease, and floating material. 

Bar Racks and Comminutors. These devices are used as the 

first step in wastewater treatment to remove large solid 

materials. Bar racks consist of large, parallel steel 

bars placed perpendicular to the flow of wastewater. The 

bars trap and retain large solids, which are removed 

mechanically by a series of vertically-moving rakes 

connected to a motor-driven, endless chain belt. The 

solids are scraped off the racks with large mechanical 

arms, and may then either be collected for land disposal 

or ground in disintegrators and returned to the flow. 

Smaller POTW's may use comminutors, which are motor-driven 

cutting devices partially submerged in a narrow channel, 

to grind up large materials as they pass through. 
DRAFT 

Grit Chambers. Grit chambers are usually found in larger 

POTW'S. They are generally located after bar racks, and are 

designed to remove sand, cinders, or other heavy particles 

that have high settling velocities. Grit chambers may be 

of two types: horizontal -flow, and aerated. Horizontal -flow 

grit chambers consist simply of a channel designed to 

maintain a constant flow velocity regardless of the volume 

of water passing through the channel. The flow velocity 

is lowered sufficiently over that of the influent wastewater 

to allow grit to settle to the bottom. Removal of the grit 

may be done either mechanically or by hand. 

Aerated grit chambers consist of a spiral-flow aeration tank. 

The velocity of flow in aerated chambers is determined by 

the volume of the tank and the quantity of air that is 

supplied. Aerated grit chambers are always cleaned 

mechanically. 

Primary Sedimentation. Primary sedimentation is used after 

preliminary removal of solids in racks and grit chambers 

and prior to biological treatment. The purpose of primary 

sedimentation, when used prior to biological treatment, is 

to reduce the suspended solids and BOD load on the biological 

treatment units. This is accomplished in large, rectangular 

(or circular) sedimentation tanks that provide a sufficient 

detention time for the removal of settleable solids and 

floating material. Grease and other floating materials are 

skimmed off from the surface with large rotating arms. 

Solids that settle to the bottom of the tank (known as 

primary sludge) are mechanically pushed into a hopper, 

where they are collected for further treatment. Primary 

sedimentation tanks, if designed properly and operated 

correctly, will remove 50 to 65 percent of the suspended 

solids in the influent wastewater and from 25 to 40 percent 

of the BOD. If primary sedimentation is used as the only 

means of treatment, the effluent is usually chlorinated to 

remove pathogens. 

Secondary Biological Treatment 

Secondary biological treatment is used to convert soluble 

and colloidal organic material into settleable flocculant 

material that can be removed in sedimentation tanks. Two 

types of biological treatment processes are most often 

employed: (1) the activated-sludge process, and (2) 

trickling filters. 
DRAFT 

Activated-Sludge Process. The activated-sludge process 

consists of an aerated basin containing a large mass of 

microorganisms and flocculated solids, known as the mixed 

liquor, followed by a sedimentation tank in which the 

solids are removed. The sedimentation tank may either be 

part of the same structure as the aeration basin, or it may 

be completely separate. Part of the solids that settle 

in the sedimentation tank (the secondary sludge) is removed 

for further treatment, and part is recycled to the aeration 

basin. The effluent from the sedimentation tanks is usually 

chlorinated. 

Bacteria make up the largest portion of the microorganisms 

present in the activated sludge, and are responsible for the 

majority of the waste stabilization that occurs. The 

mechanisms by which bacteria stabilize a waste is twofold, 

consisting of: (1) consumption of organic matter, which is 

partially oxidized to lower energy compounds and partially 

converted to new cellular material, and (2) the production 

of polymers and slime that bind bacterial cells and other 

suspended material into flocculant particles that can be 

removed by sedimentation. Other microorganisms may also be 

present, such as protoza, which consume bacteria that have 

not flocculated, and rotifers, which consume small floc 

particles that have not settled. Activated sludge systems 

are usually from 55~95 percent efficient in removing BOD, 

and from 55-95 percent efficient in removing suspended 

sol ids (Figure V-18). 

Trickling Filters. Trickling filters consist of a bed of 

rocks or plastic material that support a growth of microbial 

material (slime layer). wastewater is sprayed over the 

top of the bed, which is circular, with a rotating 

distributor. As the waste percolates through the bed, 

organic material is adsorbed onto the slime layer. At 

periodic intervals, partly because of the increase in 

thickness of the slime layer, the microorganisms in the 

layer lose their a b i l i t y t o cling to the surface of the 

filter media and the slime layer is washed off by the 

wastewater (a process called "sloughing"). (Figure V-18). 
DRAFT 

Influen 

Was i e Sludge 

Activated Sludge Process t 

Effluent 

~i udge 

Infl uen Sludge Return Line 

We1 1 

Trickling Filter Process 

nal 

dimentation 

FIGURE V-18. Flow Diagram of Secondary Treatment Methods 

V-63 
DRAFT 

Trick1 ing filters are divided into two categories: low-rate 

and high-rate, based on organic loading rates. Both types 

of filters achieve equivalent BOD removal efficiencies, but 

high-rate filters are advantageous since they have a higher 

rate of BOD removal (and thus can accept higher influent 

flow rates) than low-rate filters. This is achieved by 

recycling a portion of the influent to return viable 

organisms back to the filters. Low-rate filters have no 

recycle. Both types of filters are followed by a settling 

tank (clarifier) to remove suspended solids produced during 

sloughing. The effluent from the settling tank is generally 

chlorinated. Trickling filters are from 50-95 percent 

efficient in the removal of BOD, and 30-92 percent efficient 

in the removal of suspended solids. 

Figure V-19 shows a wastewater treatment process diagram 

utilizing activated sludge or trickling filters. 

T-reatment and Disposal of Sludge. 

The problem of disposing of sludges produced during primary 

and secondary treatment is one of the most complex tasks 

faced by the engineer. Techniques for dealing with sludges 

are varied, but most involve: (1) digestion, followed by (2) 

conditioning, and (3) dewatering and drying (Figure V-20). 

Digestion is a biological process for reducing the volume of 

sludge. Two types of digesters are in use: anaerobic, 

and aerobic. Anaerobic digesters are closed, heated tanks 

in which various microorganisms decompose organic and/or 

inorganic matter without the presence of oxygen, forming 

methane, carbon dioxide, and sludge solids. The methane 

that is involved during the process can be used as a fuel, 

and its rate of production is one of the best measures of 

the satisfactory operation of the digester. Chemical 

conditioning, followed by centrifugation or vacuum filtration, 

is usually used to treat sludge solids during anaerobic 

digestion. Chemical conditioning involves the use of ferric 

chloride, lime, alum, or organic polymers to coagulate the 

solids and release absorbed water. Centrifugation and vacuum 

filtration are physical operations that are used to remove 

water from the sludge solids prior to final disposal. 

Aerobic digestion is much like the activated sludge process, 

involving consumption of organic compounds in sewage by 

an aerated mass of microorganisms. As the supply of organic 

material run out, the microorganisms begin to consume their 

own protoplasm. Sludge sol ids from aerobic digesters are 

stable and are more easily dewatered by vacuum filtration or 

drying on sand beds. 
Acitvated Sludge 

Treatment Scheme 

Screenings Grit Sludge Waste sludge 

Return sludge C'2 f L 

Primary Trickling Chlorine Bar racks Grit chambers sedimentation filters Settl jng tank contact chamber 

t 

Screenfngs Grit ~l udge Waste sludge 

Trickling Filter 

Treatment Scheme 

b 

r Y, 

I 

FIGURE V-19. Wastewater Treatment Flow Diagram 

Influent - 

r Return effluent 

L - 

t. 

r 

- 

P 

Primary Aeration tank settl ing tank Chlorine 

Bar racks Grit chambers sedimentation contact chamber 

* 

r P 3- 

+ F 

Effluen 

I 

Influent 1 1 - - Effluent 

3 
Ana,erobic sludge 

digestion Chemical conditioning centrifuge 

FIGURE V-20. Flow Diagram for Sludge Treatment 

* 

Sludge from sedimen- 

 ati ion tanks 

sludge 

f 

Supernatant Sludge Disposal Scheme Dewatered sludge to 

ultimate disposal o 

;O 

> 

-r1 

-4 

r 

Digested 

Centrat I 

- - r c 

r 
DRAFT 

Tertiary Treatment 

Many chemical constituents present in wastewater, especially 

nitrogen and phosphorus, are slightly affected by conventional 

primary and secondary treatment. Since these chemicals can 

have adverse effects on the receiving water by promoting the 

growth of algae and other unwanted aquatic vegetation, their 

removal is desirable in some cases. Although tertiary 

treatment processes are still uncommon, their use is receiving 

considerable attention. Two processes, nitrification for 

the removal of nitrogen, and precipitation for the removal 

of phosphorus, will be discussed. 

Nitrification-Denitrification. This process appears to be 

the most promising for the removal of nitrogen. The technique 

involves aerobic conversion of ammonia to the nitrate form 

(nitrification), followed by anaerobic conversion of the 

nitrates to nitrogen gas (deni trification). Both steps 

involve the production of specialized groups of bacteria, 

and require detailed attention to operating and environmental 

conditions. Denitrification requires the addition of a 

supplemental carbon source for successful operation. Methanol 

is usually used. Nitrification-denitrification is from 

60-65 percent efficient in removing nitrates. Figure V-21 

shows a flow diagram of the nitrification-denitrification 

process. 

Chemical Precipitation. Precipitation of phosphorus can be 

achieved by the addition of chemicals such as lime, alum, 

and ferric- chloride, or sulfate. These chemicals are usually 

added to the raw wastewater and the phosphorus is 

precipitated during primary sedimentation, however, these 

chemicals can also be added in the activated-sludge aeration 

tank or to the secondary clarifier. Removal of phosphates 

by precipitation in primary sedimentation tanks is from 90- 

95 percent efficient. 

EFFECTS - OF STEAM-ELECTRIC WASTEWATERS - ON POTW'S 

The wastewaters discharged by steam-electric plants vary 

greatly in flow and waste loadings. For the twenty-two 

plants visited during this study, the steam-electric 

wastewaters represented less than five percent of the 

total POTW influent. Table V-13 lists the combined discharge 

rate for each steam-electric plant along with the associated 

POTW influent flow and treatment scheme. 
Nitrification 

Nitrogen Removal 

Scheme 

Waste sludge ~aste sludge 

pH adjustment pH adjustment A 

Chemical 

addition 

Denitrification 

Secondary t 

effluent . r 

I 

FIGURE V-21. Flow Diagram of Ni tr-ification - Deni trification Process 

r Final effluent 

Plug flow reactor plug flow reactor 

Sludge return Sludge return 

Settling tank Settl ing tank 
Table V-13. POWER PLANT AND POTW FLOWS 

15,000 I 10.0 x lo6 I 0.15 I Activated sludge, 

(56,700) (22.7 x 106) aerobic digestion I 

--- 

Plant 

No 

9600 

9650 

9369 

Combined Flow 

to POTW, gpd 

(]/dl 

No data (plant has been 

usin POTW for only one 

year! 

100.00 

(378,000) 

2.350 

(8.880) 

1.580 

(5,970) 

2.000 

9585 

POTW Average 

Flow, gpd 

(l/d) 

97.5 x lo6 

(369 x lo6) 

2.4 x lo6 

(9.1 x 106) 

300,000 

(1.1 x 106) 

3-50 x 1 o6 

7116 

8696 

81 35 

91 63 

6387 

8392 

1.4 x 10 1 1.9 1 Activated sludge 1 (1.3 x 106) I 

(7,560) 

600 

(2,270) 

16214 1 No data - operates only 1.4 x lo6 1 (5.3 x lo6) 1 -- I Activated sludge 50 hourslyr I 

% of POTW 

Flow 

0.10 

0.098 

0.50 

0.01 

Data incomplete 

173.000 

(654,000) 

150,400 

46.900 

(1 77.000) 

9,500 

(35,900) 

126,000 

(476,000) 

6293 

7308 

8875 

7968 

POTW 

Treatment Scheme 

- 

Actfvated sludge, 

anaerobic digestion 

Rotating biological 

surfaces; anaerobic 

dioestion 

Activated sludge. 

aerobic digestion 

Activated sl udse. 

(1,320 x lo6) 

4.5 x lo6 

(17.0 x lo6) 

2 x lo6 

(7.6 x 106) 

315 x lo6 

(1.190 x 106) 

31.1 x lo6 

(120 x 106) 

--- 

- - - - -- - - - 

9,100 

(34,400) 

902,000 

(3.41 x lo6) 

423,000 

(1.60 x lo6) 

Data f ncomplete 

3.5 x lo6 

(13.2 x lo6) 

350 x lo6 

(1,320 x lo6) 

6294 

0.01 

0.46 

0.29 

1.4 

- - - 

anaerobic digeition 

Oxidation pond 

--- 

0.049 

Activated sludge 

trick1 ing filters 

anaerobic digesters 

Primary treatment only 

secondary treatment 

facilities being built 

Activated sludge, 

trick1 ing filters, 

anaerobic digestion 

- -- 

I 35.000 

(132,000) 

Activated sludge 

Activated sludge. 

anaerobic digestion 

No POTW at present - to be hooked up 

to West Palm Beach POTW in 1978 - Sewers 

presently run to ocean 

1.4 x 10 6 

(5.3 x 106) 

Trickling filters; 

anaerobic disrstion 

Trickling filters; 

no digestion 

Activated sludge, 

aerobic diqestion 

10 x lo6 

(38 x lo6) 

220.000 

(832,000) 

1.5 x lo6 

(5.7 x 106) 

0.47 

4.3 

8.4 

2.5 Activated sludge 
DRAFT 

- Raw Waste Load 

Waste loads in the combined discharge are affected by any 

occurrence in the steam-electric which use and discharge 

water. The waterborne waste loads in the combined discharge 

for six (6) plants are shown in Table V-14 The major 

pollutants are chemical oxygen demand and dissolved and 

total solids, with lesser values of iron, nickel, phosphates 

and total and hexavalent chromium. 
Table V-14. RAW WASTE F L O W S A N D LOADINGS - COMBINED DISCHARGE TO POTW 

- 

LlDay LIMWH LIDay LIWH LIDay LIWWH L/l)ay L/MWH L!Day L/W&H L/@~Y LIWWH 

518.090 1870 238 .OOO 755 0 779 ,272.0OlO '19.9 35.500 150 254,000 593 

mq/l Q/NWH m~/l a/;,lWH mqll q/MWY mq/l g vg/l g1FiWH mgll g/WH 

1 Chromium 1 <O.C2 Uncertain 1 8.1 6.1 1 1.76 0.403 1 <0.02 (0.02 1 0.033 0.005 1 9.7 5.7 1 

t * 

81 35 

Combinad Dischaw 

8392 7308 6293 

- - .- 

--- 

Chrowium +6 

Copver 

Cy~nide (Total ) 

I 

w 

--.1 

PLANT NO 8696 

0.66 0.15 

0.45 0.10 - 

(0 .0005 (3.005 

Oil and Grease 

Phosphate (Total ) 

Total Dissolved 

Solids 

Total Suspended 

Solids 

Total Sollds 

Surfactants 

Zinc 

- 

Combined Discharge Combined Discharge 

6387 

I,l?T r,,,, E'rlATER SOURCE 

0.006 0.01 

0.02 0.04 

0.036 0.01 

Iron 

Nickel 

Combined Oisc9arge Combined Discharge ( Combined Discharge 

0.01 0.0004 

0.46 0.013 

<0.005 C0.005 

- 

8.0 6.0 

0.04 0.03 

<O .005 (0.005 

Quantities of parameters in combined discharge calculated by fractional addition of parameters in seperate contributing streams 

(1 .O Uncertain 

----- ----- 

1454 2719 

241 451 

1695 31 70 

0.64 1.2 

(0.03 Uncertain 

0.02C 0.003 

0.5 0.008 

(0.005 <0.005 

- 

7.19 4.26 

0.03 0.02 

0.12 0.71 

0.71 0.54 

(0.03 (0.03 

1.2 0.91 1 5.8 1.3 2.3 0.092 

0.05 0.002 

2479 98.9 

70.2 2.8 

---- ----- 

16 12 

<1 .O (1 .O 

14.7 3.37 

12 2.7 

(0.011 (0.011 

0.045 O.OC68 

----- ------ 

208C 476 

226 51.7 

0.024 0.04 

0.07 0.1 

0.059 0.035 

0.56 0.33 

(1 .O <1.0 

4.4 0.66 

580 87 

159 28.3 

16 12 

----- ----- 

1.47 0.337 

----- ------ 

2.6 2.0 

0.88 0.035 

(0.03 (0.03 

<l.o (1.0 . 

5.8 6.4 

1298 763 

5.6 3.3 

770 115 

----- ------ 

0.11 0.0044 

2306 520 1304 773 - 

5.79 0.868 

f0.03 ~0.03 

2549 102 

0.12 0.71 

(0.03 (3.03 
DRAFT 

WASTE COMPARISON 

Effluent data gathered from the eight (8) plants sampled 

during this study were compared with similar data gathered 

in support of the "Development Document for Effluent 

Limitations Guidelines and Standards of Performance for the 

Steam Electric Power Generating Point Source Category" (14). 

Comparison was made to identify similarities and differences 

in the quality and quantity of aqueous plant effluents. 

Waste streams for which data was available for comparison 

include: 

a Recirculating Condenser Cooling Water 

0 Later Treatment Wastes 

m Boi 1 er Bl owdown 

a Ash Handling Wastes 

These data may be found in Table V-15. 

Recirculating Condenser Cooling Water 

Flow data in this study tended to coincide with lower flows 

reported in the development document (14) and were similar. 

Concentrations of BOD, phosphate, dissolved solids, 

suspended solids, total solids, and zinc observed in this 

study were within the range of those reported in the 

Development Document. Concentrations of chromium, copper, 

iron and nickel observed in this study tended to be lower 

than those reported in the development document. This 

difference is probably due to lower influent loadings of 

these heavy metal components. Metals such as iron, and 

copper tend to be removed during municipal water treatment. 

Most of the plants contacted in this study used municipal 

water as raw feed water for all purposes. 

Water Treatment Wastes 

Flows and parameter concentrations of wastes observed 

in this study were within the range of those reported in 

the development document. 
DRAFT 

Boi 1 er Bl owdown 

Flow data for boiler blowdown observed in this study was 

within the range of those reported in the development 

document. Concentrations of all parameters observed in this 

study were similar to those reported in the development 

document with the exception of BOD, and zinc. BOD values 

observed in this study tended to be higher than those 

reported in the development document. Observed zinc values 

tended to be lower. BOD difference in this low range are not 

significant as the test method is not precise in this range. 

Zinc concentrations are understandably lower for all 

discharges observed in this study due to use of municipal 

water as influent water. 

Ash Handling Wastes 

Wastewater flows of ash handling wastes observed in this 

study were within the range of those reported in the 

development document (14). Concentrations of parameters 

observed in this study were within the range of those 

reported in the development document, with the exception of 

phosphate. Phosphate concentrations observed in this study 

were higher than those reported in the development document. 

Higher maximum phosphate concentrations are probably due to 

the variable nature of coal impurities. 

Summary 

Overall, values, of effluent flows and parameter concentrations 

observed in this study were similar to those reported in 

data referenced in the development document (14). The few 

parameters in this study that lay outside the range of 

development document data tended to be lower, reflecting 

the higher quality of the municipal water used as influent 

water for the stations contacted in this study. Therefore, 

it may be concluded that the stations affected by the 

results of this study are not different from those (direct 

dischargers) affected by the development document (14). 

DRAFT 

SECTION VI 

SELECTION OF POLLUTANT PARAMETERS 

INTRODUCTION 

Aqueous pollutants originating from steam electric power 

generating facilities which are of potential harm to either 

publicly-owned treatment works (POTW) or to receiving 

waters at the point of discharge of the POTW are 

identified in this section. 

RATIONALE -- FOR THE SELECTION OF POLLUTANT PARAMETERS 

Pollutants were selected based on their harmful effects on 

treatment works. If the pollutant passes through typical 

treatment works, it was selected on the basis of its 

potential for harm to receiving waters. The following 

factors were considered in this selection: 

m Potential harm to POTW. The pollutant may 

impair thexiat- biological treatment 

systems by either: (1) causing the death of 

some or all of the microorganisms that are 

essential to the operation of the POTW, or 

(2) impairing the activity of these 

microorganisms so that their waste-consuming 

efficiency is lowered. Examples of treatment 

units that may be adversely affected by 

pollutants are: trickling filters, activated 

sludge units, anaerobic digesters, and 

nitrification units. 

Potential --- harm to the receiving water. If 

the ~ollutant is not removed or is removed 

inadequately by the POTW, it may be of 

significant harm to the receiving water. In 

this respect, the pollutant may cause damage 

to the fish and plant life of the water, or 

it may render the water unsuitable for use 

for domestic, industrial, or recreational 

purposes. 
DRAFT 

Presence or absence in plant effluents 

Parameters such as total suspended solids (TSS), biochemical 

oxygen demand (BOD), and chemical oxygen demand (COD) that 

are normally removed (to a given extent) by treatment plants 

are also discussed. This discussion does not necessarily 

indicate that these parameters are of harm to a POTW, but 

only that they were part of routine analysis of effluent 

samples. 

A discussion of the effects of selected pollutants on 

treatment plants is included in Appendix C. The following 

discussion is primarily related to the effects of the 

pollutants on receiving waters. 

Properties of Selected Pollutant Parameters 

Acidity and Alkalinity - pH. Although not a specific 

pollutant, pH is related to the acidity or alkalinity of a 

wastewater stream. It is not a linear or direct measure 

of either, however, it may be properly used as a surrogate 

to control both excess acidity and excess alkalinity in 

water. The term pH is used to describe the hydrogen ion - 

hydroxyl ion balance in water. Technically, pH is related 

to the hydrogen ion concentration or activity present in a 

given solution. pH numbers are the negative logarithm of 

the hydrogen ion concentration. A pH of 7 indicates 

neutrality or a balance between free hydrogen and free 

hydroxyl ions. Solutions with a pH above 7 indicate that 

the solution is alkaline, while a pH below 7 indicates 

that the solution is acidic. 

Knowledge of the pH of water or wastewater is useful in 

determining necessary measures for corrosion control, 

pollution control, and disinfection. Waters with a pH 

below 6.0 are corrosive to water works structures, 

distribution lines, and household plumbing fixtures such as 

iron, copper, zinc, cadmium, and lead. Low pH waters not 

only tend to dissolve metals from structures and fixtures 

but also tend to redissolve or leach metals from sludges 

and bottom sediments. The hydrogen ion concentration can 

affect the "taste" of the water and at a low pH, water 

tastes "sour." 
DRAFT 

Extremes of pH or rapid pH changes can exert stress 

conditions or kill aquatic life outright. Even moderate 

changes from "acceptable" criteria limits of pH are 

deleterious to some species. The relative toxicity to 

aquatic life of many materials is increased by changes in 

the water pH. For example, metalocyanide complexes can 

increase a thousand-fold in toxicity with a drop of 1.5 pH 

units. Similarly, the toxicity of ammonia is a function of 

pH. The bactericidal effect of chlorine in most cases is 

less as the pH increases, and it is economically advantageous 

to keep the pH close to 7. 

Acidity. Acidity is defined as the quantitative ability of 

a water to neutralize hydroxyl ions. It is usually expressed 

as the calcium carbonate equivalent of the hydroxyl ions 

neutralized. Acidity should not be confused with pH value. 

Acidity is the quantity of hydrogen ions which may be 

released to react with or neutralize hydroxyl ions while pH 

is a measure of the free hydrogen ions in a solution at the 

instant the pH measurement is made. A property of many 

chemicals, called buffering, may hold hydrogen ions in 

solution from being in the free state and being measured as 

pH. The bond of most buffers is rather weak and hydrogen 

ions tend to be released from the buffer as needed to 

maintain a fixed pH value. 

Highly acid waters are corrosive to metals, concrete, and 

living organisms, exhibiting the pollutional characteristics 

outlined above for low pH waters. Depending on buffering 

capacity, water may have a higher total acidity at pH values 

of 6.0 than other waters with a pH value of 4.0. 

Alkalinity. Alkalinity is defined as the ability of a water 

to neutralize hydrogen ions. It is usually expressed as the 

calcium carbonate equivalent of the hydrogen ions neutralized. 
DRAFT 

Alkalinity is commonly caused by the presence of carbonates, 

bicarbonates, hydroxides, and to a lesser extent by borates, 

silicates, phophates, and organic substances. Because of 

the nature of the chemicals causing alkalinity, and the 

buffering capacity of carbon dioxide in water, very high 

pH values are seldom found in natural waters. 

Excess alkalinity, as exhibited in a high pH value, may 

make water corrosive to certain metals, detrimental to most 

natural organic materials, and toxic to living organisms. 

Ammonia is more irritating at higher pH. The lacrimal fluid 

of the human eye has a pH of approximately 7.0 and a deviation 

of 0.1 pH unit from the norm may result in eye irritation 

for the swimmer. Appreciable irritation will cause severe 

pain. 

-- Oil and Grease 

Because of widespread use, oil and grease occur often in 

wastewater streams. These oily wastes may be classified 

as follows: 

e Light Hydrocarbons. These include light fuels 

such as gasoline, kerosene, and jet fuel, and 

miscellaneous solvents used for industrial 

processing, degreasing, or cleaning purposes. 

The presence of these hydrocarbons may make the 

removal of other heavier oily wastes more difficult. 

Heavy Hydrocarbons, Fuels, -- and Tars. These include 

the crude oils, diesel oils, #6 fuel oil, residual 

oils, slop oils, and in some cases, asphalt and 

road tar. 

a Lubricants and Cutting Fluids. These generally 

fall into two classes: non-emulsifiable oils 

such as lubricating oils and greases, and 

emulsifiable oils such as water soluble oils, 

rolling oils, cutting oils, and drawing 

compounds. Emulsifiable oils may contain fat 

soap or various other additives. 

0 Vegetable and Animal --- Fats and Oils. These 

originate primarily from processing of foods and 

natural products. - 

- 
DRAFT 

These compounds can settle or float and may exist as 

solids or liquids depending upon factors such as method 

of use, production process, and temperature of 

wastewater. 

Oil and grease even in small quantities cause troublesome 

taste and odor problems. Scum lines from these agents are 

formed on water treatment basin walls and other containers. 

Fish and water fowl are adversely affected by oils in 

their habitat. Oil emulsions may adhere to the gills of 

fish causing suffocation, and the flesh of fish is tainted 

when microorganisms that were exposed to waste oil are 

eaten. Deposition of oil in the bottom sediments of water 

can serve to inhibit normal benthic growth. Oil and grease 

exhibit an oxygen demand. 

Levels of oil and grease which are toxic to aquatic 

organisms vary greatly, depending on the type and the 

species susceptibility. However, it has been reported that 

crude oil in concentrations as low as 0.3 mg/l is extremely 

toxic to fresh-water fish. It has been recommended that 

public water supply sources be essentially free from oil 

and grease. 

Oil and grease in quantities of 100 l/sq km (10 gallons/sq 

mile) show up as a sheen on the surface of a body of water. 

The presence of oil slicks prevent the full aesthetic 

enjoyment of water. The presence of oil in water can also 

increase the toxicity of other substances being discharged 

into the receiving bodies of water. Municipalities 

frequently limit the quantity of oil and grease that can be 

discharged to their wastewater treatment systems by 

industry. 

Chemical Oxygen Demand (COD) and Biochemical Oxygen 

Demand (BOD) 

The Chemical Oxygen Demand (COD) is a purely chemical 

oxidation test devised as an alternate method of estimating 

the total oxygen demand of a wastewater. Since the method 

relies on the oxidation-reduction system of chemical analyses 

rather than on biological factors, it is more precise, 

accurate, and rapid than the Biochemical Oxygen Demand (BOD) 

test. The COD test is widely used to estimate the total 

oxygen demand (ultimate rather than 5-day BOD) to oxidize 

the compounds in a wastewater. It is based on the fact that 

organic compounds, with a few exceptions, can be oxidized 

by strong chemical oxidizing agents under acid conditions 

with the assistance of certain inorganic catalysts. 
DRAFT 

The COD test measures the oxygen demand of compounds that 

are biologically degradable and of many that are not. 

Pollutants which are measured by the BOD5 test will be 

measured by the COD test. In addition, pollutants which 

are more resistant to biological oxidation will also be 

measured as COD. COD is a more inclusive measure of oxygen 

demand than is BOD5 and will result in higher oxygen demand 

values than will the BOD5 test. 

The compounds which are more resistant to biological 

oxidation are becoming of greater and greater concern not 

only because of their slow but continuing oxygen demand 

on the resources of the receiving water, but also because 

of their potential health effects on aquatic life and humans. 

Many of these compounds result from industrial discharges 

and some have been found to have carcinogenic, mutagenic, 

and similar adverse effects, either singly or in combination. 

Concern about these compounds has increased as a result of 

demonstrations that their long life in receiving watersthe result of a slow biochemical oxidation rate--allows 

them to contaminate downstream water intakes. The commonly 

used systems of water purification are not effective in 

removing these types of materials and disinfection such as 

chlorination may convert them into even more hazardous 

materials. 

Thus the COD test measures organic matter which exerts an 

oxygen demand and which may affect the health of the people. 

It is a useful analytical tool for pollution control 

activities. It provides a more rapid measurement of the 

oxygen demand and an estimate of organic compounds which are 

not measured in the BOD5 test. 

BOD. Biochemical oxygen demand (BOD) is the quantity of 

oxygen required for the biological and chemical oxidation of 

waterborne substances under test conditions. Materials which 

may contribute to the BOD include: carbonaceous organic 

materials usable as a food source by aerobic organisms; 

oxidizable nitrogen derived from nitrites, ammonia and 

organic nitrogen compounds which serve as food for specific 

bacteria; and certain chemically oxidizable materials such 

as ferrous iron, sulfides, sulfite, etc. which will react 

with dissolved oxygen or are metabolized by bacteria. In 

most industrial and municipal wastewaters, the BOD derives 

principally from organic materials and from ammonia (which 

is itself derived from animal or vegetable matter). 
DRAFT 

The BOD of a waste exerts an adverse effect upon the 

dissolved oxygen resources of a body of water by reducing 

the oxygen available to fish, plant life, and other 

aquatic species. Conditions can be reached where all of 

the dissolved oxygen in the water is utilized resulting 

in anaerobic conditions and the production of undesirable 

gases such as hydrogen sulfide and methane. The reduction 

of dissolved oxygen can be detrimental to fish populations, 

fish growth rate, and organisms used as fish food. A 

total lack of oxygen due to the exertion of an excessive 

BOD can result in the death of all aerobic aquatic 

inhabitants in the affected area. 

Water with a high BOD indicates the presence of decomposing 

organic matter and associated increased bacterial 

concentrations that degrade its quality and potential uses. 

A by-product of high BOD concentrations can be increased 

algal concentrations and blooms which result from 

decomposition of the organic matter and which form the 

basis of algal populations. 

The BOD5 (5-day BOD) test is used widely to estimate the 

pollutional strength of domestic and industrial wastes in 

terms of the oxygen that they will require if discharged 

into receiving streams. The test is an important one in 

water pollution control activities. It is used for 

pollution control regulatory activities, to evaluate the 

design and efficiencies of wastewater treatment works, and 

to indicate the state of purification or pollution of 

receiving bodies of water. 

Complete biochemical oxidation of a given waste may require 

a period of incubation too long for practical analytical 

test purposes. For this reason, the five-day period has been 

accepted as standard, and the test results have been 

designated as BOD5. Specific chemical test methods are not 

readily available for measuring the quantity of many 

degradable substances and their reaction products. Reliance 

in such cases is placed on the collective parameter, BOD5, 

which measures the weight of dissolved oxygen utilized by 

microoganisms as they oxidize or transform the gross mixture 

of chemical compounds in the wastewater. The compounds are 

related to the period of incubation. The five-day BOD 

normally measures only 60 to 80 percent of the carbonaceous 

biochemical oxygen demand of the sample, and for many 

purposes this is a reasonable parameter. Additionally, it 

can be used to estimate the gross quantity of oxidizable 

organic matter. 
DRAFT 

The BOD5 test is essentially a bioassay procedure which 

provides an estimate of the oxygen consumed by microorganisms 

utilizing the degradable matter present in a waste under 

conditions that are representative of those that are likely 

to occur in nature. Standard conditions of time, temperature, 

suggested microbial seed, and dilution water for the wastes 

have been defined and are incorporated in the standard 

analytical procedure. Through the use of this procedure, the 

oxygen demand of diverse wastes can be compared and evaluated 

for pollution potential and to some extent for treatability 

by biological treatment processes. 

Because the BOD test is a bioassay procedure, it is important 

that the environmental conditions of the test be suitable 

for the microorganisms to function in an uninhibited manner 

at all times. This means that toxic substances must be 

absent and that the necessary nutrients, such as nitrogen, 

phosphorous, and trace elements, must be present. 

Total Suspended Solids (TSS) 

Suspended solids include both organic and inorganic materials. 

The inorganic compounds include sand, silt, and clay. The 

organic fraction includes such materials as grease, oil, 

tar, and animal and vegetable waste products. These solids 

may settle out rapidly and bottom deposits are often a 

mixture of both organic and inorganic solids. Solids may be 

suspended in water for a time, and then settle to the bed of 

the stream or lake. These solids discharged with man's 

wastes may be inert, slowly biodegradable materials, or 

rapidly decomposable substances. While in suspension, they 

increase the turbidity of the water, reduce light penetration 

and impair the photosynthetic activity of aquatic plants. 

Suspended solids in water interfere with many industrial 

processes, cause foaming in boilers, and incrustations on 

equipment exposed to such water, especially as the 

temperature rises. They are undesirable in process water 

used in the manufacture of steel, in the textile industry, 

in laundries, in dyeing, and in cooling systems. 
DRAFT 

Solids in suspension are aesthetically displeasing when 

they settle to form sludge deposits on the stream or lake 

bed. They are often damaging to the l i f e i n water. Solids, 

when transformed to sludge deposits, may do a variety of 

damaging things, including blanketing the stream or 1 ake 

bed and thereby destroying the living spaces for those 

benthic organisms that would otherwise occupy the habitat. 

When of an organic nature, solids use a portion of all of 

the dissolved oxygen available in the area. Organic 

materials also serve as a food source for sludgeworms and 

associated organisms. 

Disregarding any toxic effect attributable to substances 

leached out by water, suspended solids may kill fish and 

shellfish by causing abrasive injuries and by clogging the 

gills and respiratory passages of various aquatic fauna. 

Indirectly, suspended solids are inimical to aquatic life 

because they screen out light, and they promote and 

maintain the development of noxious conditions through 

oxygen depletion. This results in the killing of fish and 

fish food organisms. Suspended solids also reduce the 

recreational value of the' water. 

Turbidity. Turbidity of water is related to the amount of 

suspended and colloidal matter contained in the water. It 

affects the clearness and penetration of light. The degree 

of turbidity is only an expression of one effect of suspended 

solids upon the character of the water. Turbidity can reduce 

the effectiveness of chlorination and can result in 

difficulties in meeting BOD and suspended solids limitations. 

Turbidity is an indirect measure of suspended solids. 

Chromium (Cr) 

Chromium is an elemental metal usually found as a chromite 

(FeCr204). The metal is normally processed by reducing the 

oxide with aluminum. 

Chromium and its compounds are used extensively throughout 

industry. It is used to harden steel and as an ingredient 

in other useful alloys. Chromium is also used in the 

electroplating industry as an ornamental and corrosion 

resistant plating on steel and can be used in pigments and 

as a pickling acid (chromic acid). 

The two most prevalent chromium forms found in industry 

wastewaters are hexavalent and trivalent chromium. Chromic 

acid used in industry is a hexavalent chromium compound 

which is partially reduced to t,he trivalent from during 

use. Chromium can exist as either trivalent or hexavalent 
DRAFT 

compounds in raw waste streams. Hexavalent chromium 

treatment involves reduction to the trivalent form prior to 

removal of chromium from the waste stream as a hydroxide 

precipitate. 

Chromium, in its various valence states, is hazardous to 

man. It can produce lung tumors when inhaled and induces 

skin sensitizations. Large doses of chromates have 

corrosive effects on the intestinal tract and can cause 

inflammation of the kidneys. Levels of chromate ions that 

have no effect on man appear to be so low as to prohibit 

determination to date. The recommendation for public 

water supplies is that such supplies contain no more than 

0.05 mg/l total chromium. 

The toxicity of chromium salts to fish and other aquatic 

life varies widely with the species, temperature, pH, 

valence of the chromium, and synergistic or antagonistic 

effects, especially that of hard water. Studies have shown 

that trivalent chromium is more toxic to fish of some types 

than hexavalent chromium. Other studies have shown opposite 

effects. Fish food organisms and other lower forms of 

aquatic life are extremely sensitive to chromium and it 

also inhibits the growth of algae. Therefore, both 

hexavalent and trivalent chromium must be considered 

harmful to particular fish or organisms. 

Copper is an elemental metal that is sometimes found free 

in nature and is found in many minerals such as cuprite, 

malachite, azurite, chalcopyrite, and bornite. Copper is 

obtained from these ores by smelting, leaching, and 

electrolysis. Significant industrial uses are in the 

plating, electrical, plumbing, and heating equipment 

industries. Copper is also commonly used with other 

minerals as an insecticide and fungicide. 

Traces of copper are found in all forms of plant and animal 

life, and it is an essential trace element for nutrition. 

Copper is not considered to be a cumulative systemic 

poison for humans as it is readily excreted by the body, but 

it can cause symptoms of gastroenteritis, with nausea and 

intestinal irritations, at relatively low dosages. The 

limiting factor in domestic water supplies is taste. 

Threshold concentrations for taste have been generally 

reported in the range of 1.0 to 2.0 mg/l of copper while 
DRAFT 

concentrations of 5 to 7.5 mg/l have made water completely 

undrinkable. It has been recommended that the copper in 

public water supply sources not exceed 1 mg/l. 

Copper salts cause undesirable color reactions in the food 

industry and cause pitting when deposited on some other 

metals such as aluminum and galvanized steel. The textile 

industry is affected when copper salts are present in 

water used for processing of fabrics. Irrigation waters 

containing more than minute quantities of copper can be 

detrimental to certain crops. The toxicity of copper to 

aquatic organisms varies significantly, not only with the 

species, but also with the physical and chemical 

characteristics of the water, including temperature, 

hardness, turbidity, and carbon dioxide content. In hard 

water, the toxicity of copper salts may be reduced by the 

precipitation of copper carbonate or other insoluble 

compounds. The sulfates of copper and zinc, and of copper 

and cadmium are synergistic in their toxic effect on fish. 

Copper concentrations less than 1 mg/l have been reported to 

be toxic, particularly in soft water, to many kinds of fish, 

crustaceans, molluscs, insects, phytoplankton, and 

zooplankton. Concentrations of copper, for example, are 

detrimental to some oysters above 0.1 ppm. Oysters 

cultured in sea water containing 0.13-0.5 ppm of copper 

deposit the metal in their bodies and become unfit as a 

food substance. 

Cyanide (CN) 

Cyanide is a compound that is widely used in industry 

primarily as sodium cyanide (NaCN) or hydrocyanic acid 

(HCN). The major use of cyanides i s i n the electroplating 

industry where cyanide baths are used to hold ions such 

as zinc and cadmium in solution. Cyanides in various 

compounds are also used in steel plants, chemical plants, 

photographic processing, textile dying, and ore processing. 

Of all the cyanides, hydrogen cyanide (HCN) is probably 

the most acutely lethal compound. HCN dissociates in 

water to hydrogen ions and cyanide ions in a pH dependent 

reaction. The cyanide ion is less acutely lethal than HCN. 

The relationship of pH to HCN shows that as the pH is 

lowered to below 7 there is less than 1 percent of the cyanide 

molecules in the form of the CN ion and the rest is present 
DRAFT 

as HCN. When the pH is increased to 8, 9, and 10, the 

percentage of cyanide present as CN ion is 6.7, 42, and 

87 percent, respectively. The toxicity of cyanides is also 

increased by increases in temperature. A rise of 10°C produced 

a two- to two-to threefold increase in the rate of the 

lethal action of cyanide. 

In the body, the CN ion, except for a small portion exhaled, 

is rapidly changed into a relatively non-toxic complex 

(thiocyanate) in the liver and eliminated in the urine. 

There is no evidence that the CN ion is stored in the body. 

The safe ingested limit of cyanide has been estimated at 

something less than 18 mg/day, part of which comes from 

normal environment and industrial exposure. The average 

fatal dose of HCN by ingestion by man is 50 to 60 mg. It 

has been recommended that a limit of 0.,2 mg/l cyanide not 

be exceeded in public water supply sources. 

The harmful effects of the cyanides on aquatic life is 

affected by the pH, temperature, dissolved oxygen content, 

and the concentration of minerals in the water. The 

biochemical degradation of cyanide is not affected by 

temperature in the range of 10°C to 35OC while the toxicity 

of HCN is increased at higher temperatures. 

On lower forms of life and organisms, cyanide does not seem 

to be as toxic as it is toward fish. The organisms that 

digest BOD were found to be inhibited at 60 mg/l although 

the effect is more one of delay in exertion of BOD than 

total reduction. 

Certain metals such as nickel may form complexes with cyanide 

to reduce lethality, especially at higher pH values. On the 

other hand, zinc and cadmium cyanide complexes may be 

exceedingly toxic. 

Iron (Fe) 

Iron is an abundant metal found in the earth's crust. The 

most common iron ore is hematite from which iron is obtained 

by reduction with carbon. Other forms of commercial ores 

are magnetite and taconite. Pure iron is not often found 

in commercial use, but it is usually alloyed with other 

metals and minerals, the most common being carbon. 
DRAFT 

Iron is the basic element in the production of steel and 

steel alloys. Iron with carbon is used for casting of major 

parts of machines and it can be machined, cast, formed, 

and welded. Ferrous iron is used in paints, while powdered 

iron can be sintered and used in powder metallurgy. Iron 

compounds are also used to precipitate other metals and 

undesirable minerals from industrial wastewater streams. 

Iron is chemically reactive and corrodes rapidly in the 

presence of moist air and at elevated temperatures. In 

water and in the presence of oxygen, the resulting products 

of iron corrosion may be pollutants in water. Natural 

pollution occurs from the leaching of soluble iron salts 

from soil and rocks and is increased by industrial 

wastewater water from pickling baths and other solutions 

containing iron salts. 

Corrosion products of iron in water cause staining of 

porcelain fixtures, and ferric iron combines with tannin 

to produce a dark violet color. The presence of excessive 

iron in water discourages cows from drinking and, thus 

reduces milk production. High concentrations of ferric and 

ferrous ions in water kill most fish introduced to the 

solution within a few hours. The killing action is 

attributed to coatings or iron hydroxide precipitates on the 

gills. Iron-oxidizing bacteria are dependent on iron in 

water for growth. These bacteria form slimes that can 

affect the aesthetic values of bodies of water and cause 

stoppage of flows in pipes. 

Iron is an essential nutrient and micronutrient for all 

forms of growth. Drinking water standards in the U.S. have 

set a recommended limit of 0.3 mg/l of iron in domestic 

water supplies based not on physiological considerations, 

but rather on aesthetic and taste considerations. 

Nickel (Ni) 

Elemental nickel is seldom found in nature in the pure 

state. Nickel is obtained commercially from pentlendite 

and pyrrhotite. It is a relatively plentiful element and 

is widely distributed throughout the earth's crust. It 

occurs in-marine organisms and is found in the oceans. 

Depending on the dose, the organism involved, and the type 

of compound involved, nickel may be beneficial or toxic. 

Pure nickel is not soluble in water but many of its salts 

are very soluble. 
DRAFT 

The toxicity of nickel to man is believed to be very low and 

systematic poisoning of human beings by nickel or nickel 

salts is almost unknown. Nickel salts have caused the 

inhibition of the biochemical oxidation of sewage. They 

also caused a 50 percent reduction in the oxygen utilization 

from synthetic sewage in concentrations of 3.6 to 27 mg/l 

of various nickel salts. 

Nickel is extremely toxic to citrus plants. It is found in 

many soils in California, generally in insoluble form, but 

excessive acidification of such soil may render it soluble, 

causing severe injury to or the death of plants. Many 

experiments with plants in solution cultures have shown that 

nickel at 0.5 to 1.0 mg/l is inhibitory to growth. 

Nickel salts can kill fish at very low concentrations. 

However, it has been found to be less toxic to some fish 

than copper, zinc, and iron. Data for the fathead minnow 

show death occurring in the range of 5 to 43 mg/l, 

depending on the alkalinity of the water. 

Nickel is present in coastal and open ocean concentrations 

in the range of 0.1 to 6.0 mg/l, although the most common 

values are 2 to 3 mg/l. Marine animals contain up to 400 

mg/l, and marine plants contain up to 3,000 mg/l. The 

lethal limit of nickel to some marine fish has been reported 

as low as 0.8 ppm. Concentrations of 13.1 mg/l have been 

reported to cause a 50 percent reduction of the photosynthetic 

activity in the giant kelp (Macrocystic pyrifera) in 96 

hours, and a low concentration was found to kill oyster 

Phosphorus (P) 

Phosphorus occurs in natural waters and in wastewaters in 

the form of various types of phosphate. These forms are 

commonly classified into orthophosphates, condensed 

phosphates (pyro-, meta-, and polyphosphorus), and 

organically bound phosphates. These may occur in the 

soluble form, in particles of detritus, or in the bodies 

of aquatic organisms. 

The various forms of phosphates find their way into 

wastewaters from a variety of industrial, residential, and 

commercial sources. Small amounts of certain condensed 
DRAFT 

phosphates are added to some water supplies in the course of 

potable water treatment. Large quantities of the same 

compounds may be added when the water is used for laundering 

or other cleaning since these materials are major 

constituents of many commercial cleaning preparations. 

Phosphate coating of metals is another major source of 

phosphates in certain industrial effluents. 

The increasing problem of the growth of algae in streams and 

lakes appears to be associated with the increasing presence 

of certain dissolved nutrients, chief among which is 

phosphorus. Phosphorus is an element which is essential to 

the growth of organisms and it can often be the nutrient 

that limits the aquatic growth that a body of water can 

support. In instances where phosphorus is a growth 

limiting nutrient, the discharge of sewage, agricultural 

drainage, or certain industrial wastes to a receiving water 

may stimulate the growth, in nuisance quantities, of 

photosynthetic aquatic microorganisms and macroorganisms. 

The increase in organic matter production by algae and 

plants in a lake undergoing eutrophication has ramifications 

throughout the aquatic ecosystem. Greater demand is placed 

on the dissolved oxygen in the water as the organic matter 

decomposes at the termination of the life cycles. Because 

of this process, the deeper waters of the lake may become 

entirely depleted of oxygen, thereby destroying fish 

habitats and leading to the elimination of desirable 

species. The settling of particulate matter from the 

productive upper layers changes the character of the bottom 

mud, also leading to the replacement of certain species by 

less desirable organisms. Of great importance is the fact 

that nutrients inadvertently introduced to a lake are, for 

the most part, trapped there and recycled in accelerated 

biological processes. Consequently, the damage done to a 

lake in a relatively short time requires a many fold increase in time for recovery of the lake. 

When a plant population is stimulated in production and 

attains a nuisance status, a large number of associated 

liabilities are immediately apparent. Dense populations of 

pond weeds make swimming dangerous. Boating and water 

skiing and sometimes fishing may be eliminated because of 

the mass of vegetation that serves as a physical impediment 

to such activities. Plant populations have been associated 

with stunted fish populations and with poor fishing. Plant 
DRAFT 

nuisances emit vile stenches, impart tastes and odors to 

water supplies, reduce the efficiency of industrial and 

municipal water treatment, impair aesthetic beauty, reduce 

or restrict resort trade, lower waterfront property values, 

cause skin rashes to man during water contact, and serve 

as a desired substrate and breeding ground for flies. 

Phosphorus in the elemental form is particularly toxic, and 

subject to bioaccumulation in much the same way as mercury. 

Colloidal elemental phosphorus will poison marine fish 

(causing skin tissue breakdown and discoloration). Also, 

phosphorus is capable of being concentrated and will 

accumulate in organs and soft tissues. Experiments have 

shown that marine fish will concentrate phosphorus from 

water containing as little as 1 ug/l. 

-- Zinc (Zn) 

Occurring abundantly in rocks and ores, zinc is readily 

refined into a stable pure metal and is used extensively as 

a metal, an alloy, and a plating material. In addition, 

zinc salts are also used in paint pigments, dyes, and 

insecticides. Many of these salts (for example, zinc 

chloride and zinc sulfate) are highly soluble in water; 

hence, it is expected that zinc might occur in many 

industrial wastes. On the other hand, some zinc salts 

(zinc carbonate, zinc oxide, zinc sulfide) are insoluble 

in water and, consequently, it is expected that some zinc 

will precipitate and be removed readily in many natural 

waters. 

In soft water, concentrations of zinc ranging from 0.1 to 

1.0 mg/l have been reported to be lethal to fish. Zinc is 

thought to exert its toxic action by forming insoluble 

compounds with the mucous that covers the gills, by damage 

to the gill epithelium, or possibly by acting as an internal 

poison. The sensitivity of fish to zinc varies with species, 

age, and condition, as well as with the physical and chemical 

characteristics of the water. Some acclimatization to the 

presence of the zinc is possible. It has also been observed 

that the effects of zinc poisoning may not become apparent 

immediately so that fish removed from zinc-contaminated to 

zinc-free water may die as long as 48 hours after the removal. 

The presence of copper in water may increase the toxicity of 

zinc to aquatic organisms, while the presence of calcium 

or hardness may decrease the relative toxicity. 
DRAFT 

A complex relationship exists between zinc concentrations, 

dissolved oxygen, pH, temperature, and calcium and magnesium 

concentrations. Prediction of harmful effects has been less 

than reliable and controlled studies have not been extensively 

documented. 

Concentrations of zinc in excess of 5 mg/l in public water 

varies widely. The major concern with zinc compounds in 

marine waters is not one of accute lethal effects, but 

rather one of the long term sublethal effects of the 

metallic compounds and complexes. From the point of view of 

accute lethal effects, invertebrate marine animals seem to 

be the most sensitive organisms tested. 

A variety of freshwater plants tested manifested harmful 

symptoms at concentrations of 10 mg/l. Zinc sulfate has 

also been found to be lethal to many plants and it could 

impair agricultural uses of the water. 

Pol 1 utants Rejected 

The pollutants bromide (Br) and surfactants were analyzed 

in all samples collected. Neither pollutant was observed 

in significant quantities. Therefore, bromide (Br) and 

surfactants are rejected as pollutants for consideration 

in this study. 
DRAFT 

SECTION VII 

TREATMENT AND CONTROL TECHNOLOGY 

INTRODUCTION 

Treatment and control technologies for potential pollutants 

discharged from steam electric power generating plants 

discharging to publicly-owned -treatment works (POTW's) are 

outlined in this section. In-process controls discussed 

include those techniques which are normally used by the 

industry or by industries employing similar processes. Such 

controls include process modifications, materials substitution, 

raw materials and products recovery, water conservation and 

wastewater reuse, and general good housekeeping practices. 

Wastewater effluents discharged to publicly-owned treatment 

facilities are sometimes treated by end-of-process physical 

or chemical systems to remove pollutants which can upset 

normal operation of the POTW. Such treatment methods are 

numerous, but they generally fall into one of three broad 

categories in accordance with their process objectives. 

These include pH control, removal of dissolved materials, 

and separation of phases. 

Of the twenty-two plants surveyed only eight provide 

end-of-pipe treatment to their waste, before discharging 

it to POTW's. The extent of treatment applied varies 

in accordance with the local requirements for discharge 

limitations. Most of the plants use retention ponds to 

equalize the flow to POTWs. These ponds also serve as 

sedimentation basins for partial removal of suspended solids 

by gravity settling and are sometimes equipped with 

skimming devices to remove floating oil. A detailed 

description of end-of-pipe treatment techniques used is 

presented in Section V of this report. 

A properly designed and maintained wastewater control and 

treatment system is essential for an overall efficient waste 

management program. In order to select and implement such a 

program, it is necessary to evaluate the controls and the 

treatment techniques applicable in each case. The choice of 

any particular control strategy requires awareness of those 

factors affecting the quantity and nature of the wastewaters 

produced as well as their amenability to acceptance and 

treatment by publicly-owned treatment works. 
DRAFT 

END-OF-PIPE TREATMENT TECHNOLOGY 

Treatment Technologies Available 

If a pollutant in a waste stream is not acceptable for 

discharge to the publicly-owned treatment plant, end-of-pipe 

treatment must be provided to remove the pollutant or reduce 

it to allowable limits. Only a few existing plants 

discharging into POTW provide end-of-pipe treatment. Yet, 

basic technology is available to remove nearly all of the 

pollutants produced by steam electric generating plants. 

This technology is shown in Tables VII-1 and VII-2. 

Table VII-1 lists potential dissolved matter removal 

methods and Table VII-2 provides a similar list of solid 

liquid separation processes. Most of the processes listed 

are in use in industrial or municipal water and wastewater 

treatment. 

End-of-pipe treatment presents difficulties for removing 

some of the chemicals used in power plants. These may 

include inhibitors, biocides, and chelating agents. For 

organic chemicals, activated carbon absorption is an 

available technology, but the low concentration of the 

organics can make the process inefficient and costly. For 

some inorganics like chromates, ion exchange is similarly 

available, but may not be economically feasible. For these 

pollutants, in-plant controls are probably the preferred 

control strategy. 

TREATMENT - OF MAJOR POLLUTANTS 

Available technology and efficiency of their removal for 

chosen pollutants are shown in Table VII-3. The following 

is a brief discussion of the problems associated with 

removal of pollutants from the power plant. 
END-OF-PIPE TREATMENT METHODS 

Ch~mi cals or Process Efficiency of Advantages , Limitations Required maintenance Demonstration status 

Method objec t 1 ves equipment used requirements removal 

Neutralization * pH adjustment. acid or base as 

usually to within required. usually 

the range of 6-9 sulfuric acid and 

lime 

1-operates at 

ambient environment 

2-well suited for 

automatic control 

3-high rate of reactions 

I-may cause 

scaling in 

tanks and 

conduits 

2-produces 

large 

quantities 

of sludge 

3-may generate 

toxic byproducts 

periodic removal of practiced extensively 

sludge by industry 

Chemical reduction reduction of 

hexavalent 

chrorium to 

trivalent 

chromium 

sulfur dioxide, pH range of 99.7'6 

sodium bisulfite, 2-3 

sodium metabisulfite. 

ferrous salts 

periodic removal of 

sludge 

1-operates at 

ambient environment 

?-well suited 

to automatic 

control 

l-requires 

careful pH 

control 

2-presence of 

oxidants 

(oxygen. 

ferric ion) 

increases required dose 

of the reducing agent 

3-Sul fur dl - oxide is 

toxic and 

corrosive 

practiced extensively 

by industry 

< 

u 

H 

Precipitation removal of ions lime, hydrogen optimum pH 

by forming sllght- sulfide, organic depends on the 

ly soluble salts precipitants, ions to be resoda ash moved 

copper-96.6% 1-operates at 

nickel-91 .7% ambient enchromium-98.8: vironment 

zinc-99.7% 2-well suited to 

phosphate-93.6% automatic control 

1-requi c a r e f u l r e s pH 

control 

2-may require 

more than a 

single step 

to remove a mixture of 

ions 

3-presence of 

periodic removal of 

s 1 udge 

practiced extensively 

by industry 

chelating 

agents (1.e.. 

cyanide) Increases the 

solubi 1 i ty of 

many metals 

Ion exchange remcval of ions by synthetic cation may require pH 

sorption on surface anion exchange adjustment 

of a sn;ld ,,,dt~1x 

cyanide-99"L 

chromi um-98: 

copper-95; 

i ron-100% 

I-operates at ambient environment 

2-well suited to 

automatic control 

3-can be used to 

recover valuable 

constituents 

periodic regeneration of resins 

1-produces 

wastewater effluent 

2-resin is sub 

Jected to 

attack by 

oxidizing 

agents (1 .e. 

nitric acid) 

)-subjected to 

clogging and 

fouling 

4-costly to 

operate 

used primarily in water 

treatment operation for 

production of boiler feedwater cadmi um-92% 

nickel-100% 

zinc-75% 

process is not highly 

developed for industrial use 

(except phenol extraction) 

Liquid/liquid removal of soluble extraction organics or chemically charged pollutants 

phenol-999 

chromium-99% 

nickel-99: 

zinc-99.. 

fluori de-68: 

immiscible solvents may require 

that may contain pH adjustment 

chelating agents 

1-can be used to 

recover valuable consti tuentr 

1-effluent required additional 

treatment 

2-subjected to 

chemical interference 

3-solvent system may deteriorate 

with reoeate 

periodic regeneratio!~ of solvent 

use 
END-OF-PIPE TREATMENT METHODS 

Method 

Disinfection 

Adsorption - 

Ch~micals or Process Efficiency of Advantages Limitations Required maintenance Demonstration status 

objectives equipment used requirements removal 

destruction of chlorine, hypo- may require pH 

microorganisms chlorite salts, bdjustment 

phenol.pheno1 

deri vat4 ves, ozone. 

salts of heavy 

metals. chlorine 

dioxide 

1-operates at 1-may cause periodic loading 

ambient en- taste an4 of ci1emi:als 

vironment color pro2-well suited to b 1 ems 

automatic control 2-disinfectant 

are compounds tox~c 

removal of sorbable activated carbon, may require pH jepend on the I-high removal ef- I-waste re- periodic regcneracontaminants synthetic sorbents adjustment nature of pol- ficiency for trace quired pre- tion of sorbent 

lutants and com- concentration treatment 

'Jositlon of E-low energy re- Z-bed requ~red 

waste quirement regeneration 

3-operates at am- 3-losses of 

bient environment sorbent 

during regenerati on 

Chemical oxidation destruction of cya- chlorine, hypochlo- H=9 5-10 99.6 2 

n i des rite salts, ozone {first step) pH.8 (second 

step) 

Distillation separation of dis- 1-multistage flash may require pH 100% 

solved matter by distillation adjustment 

evaporation of the Z-multiple-effect 

water long-tube verti- cal evaporation 

3-submerged tube 

evaporation 

4-vapor compres- siun 

Reverse osmosis separation of dls- 1-tubular membrane solved matter by 2-hollow-filter 

filtration through modules 

a semipermeable 3-Spiral-wound flat 

membrane sheet membrane 

Electrodialysis removal of 

dissolved 

polar compounds 

solute is exchanged 

between two liquids 

through a selective 

semipermeable membrane in response to 

differences in chemical potential between 

two liquids 

l-operate at am- bient temDeratur 

?-well suited to 

automatic 

l-require care- Periodic removal of 

.e ful pH con- sludge and loading 

trol of chemicals 

2-may produce 

control poisonous 

gas 3-second reaction is 

slow 

4-subjected to 

chemical 

interference 

1-produces high 1-high energy periodic cleaning to 

quality water requirement remove scale 

2-can be used to 2-may require 

recover valu- pretreatment 

able constit- of waste 

uents 3-cause scaling of 

boilers and 

heat exchangers 

4-may require 

post treatment of 

water 

disinfection by chlorine 

is by practiced lndustry 

extensively 

practiced extensively 

by industry 

practiced extensively 

by industry 

practiced only to a moderate 

extent by industry, primarily 

the submerged tube type unit 

1-produces high 1 - l i m i t e d range periodic replacemerlt of very liriited use in 

quali ty water of operating membrace industrial wastewater 

2-can be used to temperatures treatment 

recover valuable and concenconstituents trations 

3-operates at am- 2-membrane is 

bient tempera- susceptible 

ture to fouling by 

suspended 

solids or attack by 

many chemicals 

TOS-62-961 1-can be used to 1-membrane is penodic replacement of not practiced by 

recover and re- subjected to membranes and electrodes industry 

use valuable fouling by 

chemicals suspended~ 

2-produces high solids 

quality water 2-membrane and 

electrode are 

subjected to 

corrosion by 

chemicals 
- Method 

END-OF-PIPE TREATMENT METHODS 

Ch~micals or Process object1 ves equipment used Efficiency of Advantages Limitations' reauirements removal Required maintenance Demonstrat~on status 

Freezing separation of so- I-direct refrlgerlute from liqu~d atlon by crystallizing 2-indirect refrigthe solvent eration 

>99 5 1-produces high \-high energy periodic cleaning and re- unproven method in quality water requirement placement of filters and waste treatment 

Z-low operating 2-refrigerant screens application 

temperature may be coninhibit5 taminated in 

corrosion the direct refrlgeratlon 

method 
SOLID/LIQUID SEPARATION SYSTEMS 

Unit operation Process objectives Methods or Retention Chemicals Efficiency Advantages 

units used time used of removal 

Skimming removal of floating 

solids or liquid 

wastes from the water 

1-15 min none 70-902 1-simple to operate 

2-reduces down stream treatment 

3-high efficiency of 

removal 

t 0 

coagulants, 15 mgll 

coagulant aids, 

pH adjustment 

Clarification 

Flotatf on 

removal of suspended 

solids by settling 

I-high efficiency of 

removal in short 

time and space 

separation of suspended solids by 

flotation followed by 

skimming 

1-froth flotation 20-30 

2-dispersed air mi n 

flotation 

aluminum and 90-991 

ferric salts, 

activated silica organic 

polymers 

1-efficient process 

3-dissolved air 

flotation 

4-gravi ty flotation 

5-vacuum flotation 

Microstraining removal of suspended 

solids by passing the 

wastewater through a 

microscreen 

none 70-801 

(23p) 

50-601 

1-no chemicals require - ment 

2-low cost of operation and maintenance 

3-high efficiency of 

removal of large 

particles 

1-low initial and 

operating costs 

2-small land requirement 

3-no chemicals requirement 

4-partial removal of 

dissolved matter 

Filtration removal of suspended 1-multimedia bed NIA 

solids by filtration 2-mixed media bed 

through a bed of sand 

and gravel 

none 

1-protect down stream treatment equipment 

2-inexpensive devices 

Screening 

Thickening 

removal of large solid 1-coarse screens N/A 

matter by passing 2-bar screens 

through screens 3-communicating 

devices 

none 

none depends on 

the nature 

of sludge 

1-facilitates further 

sludge processing 

at minimum cost 

2-flotation thifkeners are more efficient 

than gravity thickeners 

concentration of 1-gravi ty thick- NIA 

sludge by removing ening 

water 2-air flotation 

thickening 

1-high separation 

efficiency for 

difficult to remove solids 

2-filter cake has a low water content 

3-suspended solids content of fil- trate ls low 

4-minimum maintenance 

Pressure 

filtration 

separation of solid from 

liquid by passing 

through a semipermeable 

membrane under pressure 

1-3 hrs none to 50-75% 

moisture 

content 

I-produces disposable product Heat drying reduce the water content 1-flash drying N/ A of sludge 2-spray drying 3-rotary kiln 

drying 

4-multiple hearth 

drying 

none to 8% 

moisture 

content 

Total solid 

removal of 

95% and 

above 

I-low capital installation and operating costs 

2-unsensi tivi ty to the chemical nature 

of waste 

3-110 waste pretreatment is required 

Ultrafiltration separation of macro- molecules of sus- pended matter from the 

waste bv filtration 

none 

through* a semipermeable 

membrane under pressure 

1-covered beds 

2-uncovered beds 

filtration 

1-2 day 

as filter 

l5-2O% 

1-low costs Of 

construction, 

operati on and 

maintenance 

Sandbed drying removal cf moisture .. from sludge by evaporation and drainace 

through sand. 

none 

Vacuum 

filtration 

solid liquid 

separation by vacuum produces 

30% solid 

in filter 

cake 

1-highly efficient 

process none 

1-small space 

requirement 

2-simplicity in 

operation 

Centrifugation liquid/solid separation by centrifugal 

force 

1-disccentrifuge N/A 

2-basket ceotri fuge 

3-conveyor type 

centrifuge 

none moisture IS 

reduced to 

65-701 

1-highly efficient 

process separation between 

emulsified oil and 

water 

2-8 hour aluminum 

salts. iron 

salts, pH 

adjustment 

(3-4) 

Emulsion 

breaking 
SOLID/LIQUID SEPARATION SYSTEMS 

Unit operation Limitation Energy Maintenance Demonstration 

requirement status 

Skimming 1-limited to wastewater small 

containing floating 

matter 

periodic lubri- practiced extensively by 

cation industry 

Clarification 

Flotation 

I-high operating cost nominal periodic loading practiced extensively by 

of chemicals and industry 

removal of sludge 

1-efficiency depends on nominal 

the nature of the parroutine maintenance practiced extensively by 

of pumps and motors industry 

ticles surface 

routing cleaning practiced only to a moderate 

of screens extent, primarily in municipal 

wastewater treatment plants 

Microstraining 1-may result in high 

head loss 

2-low efficiency of 

removal of small 

 articles 

small 

Filtration 1-wastewater with high small 

suspended solids content require pretreatment 2-high losses of head 

3-produces wastewater 

4-operation is cornlicated and requires training 

routine main- practiced extensively primarily 

tenance of pumps in water treatment plant 

1-minor effect on 

overall treatment 

2-may result in high 

hued loss 

small periodic cleaning practiced extensively 

by industry Screening 

Thickening periodic cleaning practiced extensively 

lubrication by industry 

I-sensitive to flow 

rate of both 

effluent and sludge 

removal 

small 

small periodic cleaning not practiced by 

and replacement industry 

of filter 

Pressure 

filtration 

1-short life of filter 

cloth 

2-requi res operating 

personnel 

Heat drying 1-costly process hlgh periodic cleaning rotary kilns are used 

by industry to small 

extent 

Ultrafiltration 1-lir~ited range of nominal 

operating temperature 2-membrane is susceptible to attack 

by many chemicals 

3-limited range of 

applications 

4-membrane can be 

fouled by suspended 

solids 

routine maintenance used by industry 

of pumps primarily to treat 

oily waste 

small periodic removal practiced extensively 

of sludge by industry 

Sandbed 1-requires a large area of land . 

Vacuum 

filtration 1-hioh operating 

COS t 

2 - f i l t r a t e may require further 

treatment 

r.ominal 

nominal 

periodic cleaning practiced extensively 

and replacement by industry 

of filter media 

Centri fugation Operating 

\ cost 

2-may produce noise 

periodic lubrica- equipment for intion and cleaning dustrial wastewater 

treatment is under 

development 

Emulsion I-requires segre- small 

breaking gation of oily 

waste from non oily waste 

routine maintenance practiced extensively 

of pumps and motors by industry 

and periodic re- moval of sludge 
DRAFT 

Table VII-3. TREATMENT OF MAJOR POLLUTANTS 

Residua 1 concentration 

Pol 1 utant Treatment method achievable (mgll ) (1 7) 

Common 

DH Neutral ization 

Clarification 

Flotation 

Fi 1 tration 

Total suspended solids 1 - 

2 - 

3 - 

h S ecific Grease Skimming 

Gravity flotation 

Dissolved air flotation 

Hexavalent chromium 1 - Chemical reduction 

Chromium (total ) 1 - 

2 - 

Precipitation 

Ion exchange 

Iron 1 - Precipitation 

Copper Precipitation 

Ion exchange 

Zinc Precipitation 

Ion exchange 

Chlorine 1 - Dissipation 

Aeration 

Chemical reduction 

Below detection limits 

Be1 ow detection 1 imi ts 

Below detection 1 imi ts 
DRAFT 

-- Total Dissolved Solids. Removal of total dissolved 

solids (TDS) from wastewaters is one of the more difficult 

and more expensive waste treatment procedures. Where TDS 

result from heavy metal or hardness ions, reduction can be 

achieved by chemical precipitation methods; however, where 

dissolved solids are present as sodium, calcium, or potassium 

compounds, then TDS reduction requires more specialized 

treatment, such as reverse osmosis, electrodialysis, 

distillation, and ion exchange. 

Total Suspended Solids. Suspended solids removal can 

be achieved by sedimentation and filtration operations. 

sedimentation- lagoons are commonly used at steam electric 

power plants. Some plants employed configured tanks. 

Tanks can be used where space limitations are important. 

Tanks constructed for solids removal usually have built-in 

facilities for continuous or intermittent sludge removal. 

Designs based on maximum flow anticipated can provide the 

best performance. Equalization can be provided to regulate 

flow. The retention time required is related to the 

particle characteristics. 

-- Oil and Grease. Certain preventative measures can be 

applied to prevent spillage of oil and the entrance of oil 

into the plant drainage system.' Flotation is efficient in 

removing emulsified oil and requires minimum space. It 

can be used without chemical addition, but demulsifiers 

and coagulants can improve performance in some cases. 

Whenever possible, primary separation facilities should be 

employed to remove free oil and solids before the water 

enters the flotation unit. Multistage units are more 

effective than single-stage units. Partial recycle units 

are more effective than full-pressure units. Oil removal 

facilities including single-cell flotation can achieve 

effluent oil and grease levels from 10-20 mg/l, while 

multistage units can achieve 2-10 mg/l. 

-- Chromium. The most common method of chromium removal 

is chemical reduction of hexavalent chromium to the 

trivalent ion and subsequent chemical precipitation. The 

standard reduction technique is to lower the waste stream 

pH to 3 or below by addition of sulfuric acid, and to add 

sulfur dioxide, sodium bisulfite (or metabisulfite or 

hydrosulfite), or ferrous sulfate as a reducing agent. 

Trivalent chromium is then removed by precipitation with 

lime at pH 8.5-9.5. 

The residual of hexavalent chromium after the reduction step 

depends on the pH, retention time, and the concentration and 

type of reducing agent. 
DRAFT 

A process for chromate removal from cooling water has been 

recently developed. This is an electrochemical process 

whereby an electrical current is applied to a consumable 

iron electrode. The resulting ferrous ions react with the 

wastewater chromate in accordance with the following equation: 

Because of the alkaline pH both the iron and chromium 

precipitate as metal hydroxides and are subsequently 

removed in a clarifier. The produced ferric ion further 

enhances the coagulation and settling of suspended solids. 

Chromate residuals from this process have been reported to 

be less than 0.05 ppm. Costs of treatment are claimed to 

be fairly low and the operation is automatically controlled. 

The process is also applicable for removal of other metals 

ions such as zinc, copper, nickel, tin, iron, etc. (16). 

Copper. Effluent concentrations of 0.5 mg/l can be 

consistently achieved by precipitation with lime employing 

proper pH control and proper settler design and operation. 

The minimum solubility of the metal hydroxide is in the 

range of pH 8.5-9.5. In a power plant, copper can appear in 

the wastewater effluent as a result of corrosion of coppercontaining components of the necessary plant hydraulic 

systems. Normally, every practicable effort is made, as a 

part of standard design and operating practice to reduce 

corrosion of plant components. Copper is not usually used in 

construction of once-through boilers and consequently, is 

rarely found in corresponding spent cleaning solutions (12). 

Excessively stringent effluent limitations on copper may 

necessitate complete redesign and alteration of condenser 

cooling and other systems. A significant problem in 

achieving a low residual concentration of copper can result 

if complexing agents are present, especially cyanide and 

ammonia. 

Iron. In general, acidic and/or anaerobic conditions 

are necessary for appreciable concentrations of soluble 

iron to exist. "Complete" iron removal with lime addition, 

aeration, and settling followed by sand filtration has been 

reported. Existing technology is capable of soluble iron 

removals to levels well below 0.3 mg/l. Failure to achieve 

these levels would be the result of improper pH control. 

The minimum solubility of ferric hydroxide is between 7 and 

8 (12). In some cases, apparently soluble iron may actually be 

present as finely divided solids due to inefficient settling 

of ferric hydroxide. Polishing treatment such as rapid sand 

filters will remove these solids. In a power plant, iron, 
DRAFT 

as with copper, can appear in the wastewater effluent as 

a result of corrosion to iron-containing components of the 

necessary plant hydraulic systems. Normally, every 

practicable effort is made, as a part of standard design 

and operating procedure, to reduce corrosion of plant 

components. Excessively stringent effluent limitations on 

iron, as with copper, may necessitate complete design and 

alteration of condenser cooling and other systems. 

Zinc. Lime addition for pH adjustment can result in 

precipitation of zinc hydroxide. Operational data indicate 

that levels below 1 mg/l zinc are readily obtainable with 

lime precipitation. The use of zinc can be minimized since 

other treatment chemicals are available to reduce corrosion 

in closed cooling water cycle. Zinc removals have been 

reported for a range of industrial systems and, generally, 

treatment is not for zinc alone. 

END-OF-PIPE TECHNOLOGY FOR MAJOR -- WASTE STREAMS 

The regulations describe the various wastewater streams as 

low volume waste sources, ash transport water, metal cleaning wastes, boiler blowdown, and cooling system wastes. It 

is also possible to classify wastewater streams by their 

temporal distribution into continuous, periodic, and 

occasional. Continuous wastewater streams will have to be 

treated on a continuous basis. The main treatment criteria 

is therefore the rate of flow. Periodic wastewater streams 

will generally be treated on a batch basis and discharged 

at a controlled rate. The treatment criteria are therefore the volume of each batch, the frequency of occurrence, 

and the rate of discharge from treatment. The occasional 

waste streams are generally produced by outside conditions 

not related to the production of electrical energy such as 

precipitation. 

Some waste streams such as cooling water are directly 

related to the production of electrical energy and will not 

be discharged if the plant is not producing power. Others 

are related to the cumulative amount of energy produced by 

the plant, but may be discharged at the time the plant is 

not in operation. Metal cleaning wastes are an example of 

this type of waste. 
DRAFT 

Continuous Waste Streams. Continuous wastewater 

streams consist primarily of coolinq - system - wastes, 

either of the once-through or the recirculating system 

blowdown type. None of the plants contacted in this study 

were found to discharge once-through cooling water to 

publicly-owned treatment facilities. Where such discharge 

occurs, consideration should be given to removing this 

discharge from the sanitary sewer system, since none of 

the possible pollutants in the cooling water will be 

removed by standard biological treatment and the large 

hydraulic loading will decrease the effectiveness of the 

POTW treatment process. 

Residual chlorine contained in once-through cooling water 

discharges can be removed by so-called "dechlorination" 

processes. Methods of dechlorination ,include addition of 

reducing chemicals, passage through fixed beds of activated 

carbon and aeration. Reducing chemicals include sulfur 

dioxide (SOZ), - sodium bisulfite (NaHS03), and sodium sulfite 

(Na2S03). Of these agents, sodium bisulfite is most 

commonry used (19). Granular activated carbon as adsorb 

chlorine compounds and is oxidized by it to carbon dioxide. 

Oxidizing chlorine compounds such as chlorine (C12), 

hypochlorous acid (HOCl), chlorine dioxide (~102)-and 

nitrogen trichloride (NC13) are sufficiently voiative to be 

removed by aeration (19).-Other active chlorine species are 

not as volatile and may not be removed. Data available to 

date do not indicate that heat discharged in this waste is 

a problem to a POTW. 

Closed cycle or recirculating cooling water system blowdown 

is discharged into POTWs by a number of plants. The discharge 

may be continuous or intermittent. Significant parameters 

of pollutants that may be found in cooling water blowdown 

may include chlorine, hypochlorous acid, sodium hypochlorite, 

phosphates, chromates, zinc compounds, organic biocides, 

dispersing agents, and depending on the constituents in the 

makeup water supply, various inorganic salts resulting from 

the concentration of those constituents and the necessity of 

maintaining the pH within certain limits. Pretreatment may 

be necessary if certain types of inhibitors and biocides are 

used as internal treatment in the cooling water system. 

These are likely to inhibit biological activity at the 

publicly-owned treatment facilities and will therefore have an 

adverse effect on the treatment operation. The extent of 

this effect will depend on the relative volumes of boiler 

blowdown and domestic wastewater. Organic compounds used as 

inhibitors, biocides, or dispersing agents are not likely to 

be degraded by secondary biological treatment and will 

therefore pass through the publicly-owned treatment facilities 

and be discharged to the receiving waters. Toxicity studies 

are being conducted with individual proprietary compounds in 

order to establish permissible levels of discharge. 
DRAFT 

End-of-pipe technology is available to remove most inorganic 

pollutants. Many inorganic pollutants are insoluble at 

alkaline pH, and can be removed by adding lime or another 

form of alkali. The degree of removal is a function of the 

solubility of the pollutant at high pH. Some specific 

pollutants such as chromium can be removed by ion exchange, 

but the ultimate disposal of the spent regenerants presents 

problems. 

Periodic Wastes. Periodic wastes include waste resulting 

from boiler and service water treatment, boiler blowdown 

(can be continous), ion exchange water treatment, water 

treatment evaporative blowdown, boiler and air heater 

cleaning, other equipment cleaning, laboratory and sampling 

streams, floor drainage, cooling tower basin cleaning, 

blowdown from recirculating wet-scrubber air pollution 

control systems, and other relatively low volume streams. 

These include all the wastes that are classified as "ash 

transport" and "metal cleaning" wastes. For plants 

discharging wastes to publicly-owned treatment facilities, 

boiler blowdown is generally not a significant source of 

pollution. Water treatment wastes may or may not be 

significant depending on the source of the water and method 

of treatment. Since most plants discharging wastes to 

publicly-owned treatment facilities also obtain their water 

from the municipal water supply system, the wastes will 

consists of normal constituents of the water supply, plus 

any chemicals used in the treatment process. If the 

treatment process is ion exchange, the wastes will contain 

inorganic acids and alkalis. Combination of watest from 

anion and cation exchanges will generally result in combined 

waste stream that is acceptable to the treatment plant. If 

the pH of the combined waste stream is outside the range of 

6.0 to 9.0 normally acceptable to biologically based 

treatment process, neutralization may be required. 

Evporation blowdown is usually high in dissolved solids, 

but otherwise acceptable for discharge to the publicly-owned 

treatment facilities. The dissolved solids consists primarily 

of concentrated constituents of the public water supply and 

do not have a-ny adverse effect on the treatment plant or the 

receiving water. 

Floor drains may be a significant source of pollution, with 

oil and grease as the most significant parameter. The 

regulations for direct discharge limit oil and grease for 

all low volume wastes taken collectively to 100 mg/l on any 

one day, and 30 mg/l average for 30 consecutive days, but 

local authorities may impose more severe limits. Most 

municipal pretreatment ordinances also limit oil and grease 

so that pretreatment may be required for removal of this 

pollutant. 
DRAFT 

End-of-pipe technology is available and is used by some 

plants. The technology consists of gravity separators, 

either unassisted or assisted by flocculants and/or dissolved 

air flotation, followed if necessary by filtration. The 

technology is able to meet the desired standards at a 

minimal cost. However, to meet desired standards efficiently 

only those waste streams containing excessive oil and grease 

should be passed through the treatment unit. 

Metal Cleaning Wastes. The most significant of the 

periodic wastes in terms of their potential impact on the 

pub1 icly-owned treatment facilities are metal cleaning wastes. 

Metal cleaning wastes are produced intermittently while 

units are shut down. The efficiency of electric power 

production depends largely on the efficiency of heat transfer 

between the combustion products and the boiler water. All 

metallic heat transfer surfaces have a tendency to either 

corrode or collect deposits. Both corrosion products and 

deposits reduce the efficiency of heat transfer and must 

therefore be removed periodically. 

There are two main types of cleaning operations: waterside 

and fireside. Waterside cleaning consists of cleaning the 

inside of tubes, and other boiler water passages. Due to 

the inaccessibility of these surfaces, the only practical 

and generally accepted method of cleaning is by chemical 

means. The cleaning typically proceeds in three stages: a 

bromate soak, an acid cleaning (usually inhibited hydrochloric 

acid), and finally a passivation stage. The total operation 

takes about two days and produces about five boiler volumes 

of wastes, with each stage consisting of a fill, drain, fill 

and rinse operation lasting about 1-112 112 to 2 hours. For 

multiunit plants, only one boiler is cleaned at any one 

time, so that the majority of the plant is operating during 

the cleaning cycle. 

Fireside cleaning is more mechanical, consisting of high 

pressure nozzles directed against the surfaces to be cleaned. 

The cleaning solution often contains alkalis to dissolve 

oil, and grease and detergents to keep the removed material 

in colloidal suspension. Fireside cleaning is done on both 

the boiler and the air preheater. 

Pollutants contained in the cleaning solutions consist of 

both the chemicals used in the cleaning solution and the 

material removed from the heat transfer surfaces. Tables 

VII-4 and VII-5 give ranges of composition for chemical 

cleaning and fireside cleaning wastes, respectively. These 

pollutants are generally not removed by biological secondary 

treatment and may have an adverse effect on the treatment 

process, depending on the ratio of metal cleaning wastes to 

total flow at the publicly-owned treatment plant. 
DRAFT 

Table VII-4.TYPICAL COMPOSITION OF 

BOILER CHEMICAL CLEANING WASTES 

Component 

Hydrochloric Acid 

Iron 

Copper 

Sodium Borate 

Ammonium Carbonate 

Ammonium Hydroxide 

Chromate Inhibitors 

Thiourea 

Ammonium Bifluoride 

Sodium Carbonate 

Amount, Ib. 

plus small amounts of silica, phosphates, nickel, 

zinc, aluminum, titanium, manganese and magnesium. 

Size of unit 

Volume of wastes 

500 MW 

95,000 gal 

Table VII-5. TYPICAL COMPOSITION OF 

BOILER FIRESIDE WASH WASTE 

Component 

Suspended Solids 

Iron 

Copper 

Nickel 

Zinc 

Oil and Grease 

Volume, gal/KW IGC 

(once/year for each boiler) 

Concentration, mg/l 
DRAFT 

Options for process modifications for metal cleaning wastes 

are small. End-of-pipe technology is available for the 

removal of most of the pollutants resulting from metal 

cleaning operations. 

Basic technology for removing pollutants from the waste 

stream consists of retention, storage and combination of 

waste streams, raising the pH to precipitate metallic salts, 

and pH readjustment for discharge to public sewers. 

With the increased use of organic materials for cleaning 

solutions, the use of incineration in power plant boilers 

has become a practical alternative for the disposal of 

chemical cleaning waste. One limitation on the use of 

incineration is the need for a reserve boiler to incinerate 

the wastes. However, in the vast majority of cases, power 

plants consist of at least two units, so that this limitation 

would only occur in a few instances. Further, power plants 

with only one boiler can store cleaning wastes in holding 

tanks and incinerate them when the cleaning operation is 

over. 

Since metal cleaning wastes are only rarely produced, 

(some plants clean their boiler only once every five years) 

many plants prefer to have them hauled off and treated by 

private contractors. Most of the expertise for treating 

cleaning wastes has been developed by the cleaning contractors 

who are generally being asked to include waste treatment 

and disposal as part of the cleaning contract. 

Ash Transport Water. Hydraulic systems for handling 

bottom ash are used primarily by coal-fired plants. The 

preliminary listing of plants discharging to publicly-owned 

treatment plants contain coal-fired plants. Hydraulic 

systems are used for fly ash removal, usually in conjunction 

with scrubbers for sulfur dioxide removal. Where scrubbers 

are part of the air pollution control system, provision has 

to be made for handling of the sludges resulting from the 

operation. This sludge is not suitable for disposal to the 

public sewer system. 

Air Pollution Control Wastes. There is normally no liquid 

effluent from sulfur dioxide scrubbers. The water within 

the system is usually recycled as much as possible by 

dewatering the sludge to a filter cake. Some water leaves 

the system as steam with the gaseous emissions and some 

water becomes entrained in the sludge cake, but the objective 

of good operation is to minimize the amount of water in the 

sludge cake. The water retained in the sludge cake is 

sufficient to meet the requirements for system blowdown. 
DRAFT 

Occassional Wastes. Occassional wastes are those that 

are caused by contamination of stormwater runoff by materials 

stored on the plant site. The principal type of contaminated 

stormwater is coal pile runoff, and this is restricted to 

coal fired plants. A significant number of urban plants 

have been converted from coal to oil fired, but still retain 

the coal capability and may keep a coal reserve stored on 

the site. The coal reserve may become a significant source 

of pollution due to the interaction of water and air with 

some of the impurities in the coal, notably iron and sulfur. 

No plants discharging coal pile runoff to publicly-owned 

treatment facilities were uncovered during the industry 

survey. 

A type of process modification would be to cover the coal 

pile with plastic sheeting the way a baseball infield is 

covered in the rain. This would eliminate the formation of 

waste stream. Alternately, the waste stream, once produced, 

can be neutralized with lime as an end-of-pipe treatment, 

and any suspended solids allowed to settle. This practice 

is common in related industries. 

WATER MANAGEMENT 

The varied uses that are made of water in a power plant and 

the wide range of water quality required for those uses 

present this industry with an unusual opportunity for water 

management and wastewater reuse. Since power plants dispose 

a great portion of their water by evaporation, it is feasible 

that such plants can be operated with zero water discharge. 

Indeed, many plants developed water management programs that 

make use of all the wastewater streams produced by recycling 

them into unit processes which tolerate lower water quality 

(e.g. ash handling). However, to develop and implement a 

water management program of no discharge, it is necessary to 

evaluate the water requirement of each segment of the 

process as well as the specific factors which affect 

individual plant water needs. Such factors include the 

nature of the raw water source, the location of the plant 

and its climatic environment, water availability and water 

cost, and the local requirement for effluent limitations. 
DRAFT 

The chemical composition of the raw water source affects the 

magnitude of the discharge from almost every segment of the 

process. To deionize water with high dissolved solids 

content to produce boiler feedwater, the ion exchange system 

must be regenerated more often. Further, highly dissolved 

solids contents would also lower the concentration cycle of 

closed-loop recirculations cooling system, and therefore 

would increase the blowdown from these systems. In areas of 

excessive rainfall closed-loop recirculating systems would 

have to be bled more often to prevent the systems from 

overflowing and may indeed be difficult to operate. In 

areas where the rate of evaporation is greater than the rate 

of precipitation, such systems would require makeup water to 

maintain the flow. Water availability and cost would have 

an impact on the plant incentive to conserve water. The 

extent of wastewater treatment provided by the plant would 

depend on how stringent the local requirement for effluent 

limitations are. 

IN-PLANT CONTROL TECHNIQUES 

Control of wastewater effluents produced by the industry can 

be best achieved by incorporating in-process changes capable 

of reducing the volume of wastewater discharged, or reducing 

the amount of pollutants in the discharge. 

Such changes can be classified under one of the following 

categories: 

Process modifications; 

e Materials substitution; 

o Water conservation and wastewater reuse; 

@ Raw materials and product recovery; and 

o Good housekeeping practices. 

Application of such techniques can result in multiple 

benefits, including savings in construction and operation 

costs of on-site wastewater treatment plants and in sewer 

surcharge and other charges associated with the use of 

publicly-owned treatment facilities. 

In power generating plants there are theoretical opportunities 

for a number of such control measures. Practically, the 

opportunities are limited by the cost of any major process 

change under "retrofit" conditions, that is, conditions 

which require substantial mechanical and structural changes 

to an existing plant. 

Process Modifications 

A great number of process modifications are available to 

reduce the quantities of wastewater from a power generating 

plant, or to eliminate it altogether. In order to present 
DRAFT 

these potential modifications in an orderly manner, this 

section has been further divided into subsections, each 

dealing with an individual wastewater stream. 

Once Through Cooling Water. Switching from a oncethrough to a closed or open recirculating cooling system 

would greatly reduce the amount of wastewater discharged. 

This can be shown by balancing the quantity of heat rejected 

by each of the systems. For a once-through cooling system 

this quantity is equal to the product of the water flow 

times the condenser temperature rise. -For a recirculating 

system it can be assumed that all the heat is rejected by 

evaporation. Neglecting drift and windage losses the 

following equation can be written: 

where B/F is the ratio of the blowdown from a recirculating 

system to the discharge from once-through cooling system, AT is the condenser temperature rise, q is the amount of 

heat required to evaporate a unit weight of water, and C is 

the concentration cycle. The concentration cycle is defined 

as the ratio of the concentration of a limiting parameter in 

the makeup water to that in blowdown. For a typical condenser 

temperature rise of 10°C and for q equal to 555 kcallliter 

of water, even at a concentration cycle of 2, approximately 

98 percent reduction in the volume of wastewater produced 

would be achieved. This reduction in cooling water 

consumption can also be classified under water conservation 

and wastewater reuse category. 

Switching from once-through to a recirculating cooling 

syste, however, is costly and not always feasible. Power 

plants-contacted in this study that utilize once-through 

systems discharge the effluent directly to surface water. 

Such discharges are subjected to EPA regulations which 

limit the temperature and the chlorine concentration of 

waste effluents to be discharged to surface water. 

Excess total residual chlorine concentration in effluents 

from once-through cooling system can be minimized by monitoring 

and controlling free available chlorine concentrations in 

the discharge stream. A further technique to reduce total 

residual chlorine discharged is to chlorinate during periods 

of low condenser flow. Alternatively, the chlorine input to 

once-through cooling water can be reduced to a level below 

the concentration required for complete fouling control. 

Any biological growth which may result would be removed by 

mechanical means (12). This approach however, is limited by 

the configuration of the process piping and structures 

involved at any plant. 
DRAFT 

Closed Condenser Cooling System Blowdowns. Although 

the volume of recirculating cooling system blowdown is 

considerably smaller than the amount of wastewater discharged 

from a once-through system, it is also significantly more 

polluted. The effluent contains a higher dissolved solids 

concentration due to the evaporation of a large portion of the 

cooling water. In addition, chemicals added to inhibit 

scale formation, corrosion, and fouling would also be 

present in the blowdown water. 

Blowdown from a recirculating cooling system can be 

disposed of by evaporation. In warm, dry climates, and 

where land costs are relatively low, such as in the southwest, 

blowdown streams can be collected in ponds and allowed to 

evaporate. Such ponds are usually lined with impervious 

material such as clay or plastic to prevent water infiltration 

and subsequent pollution of the groundwater aquifer (12). 

The residual chlorine concentration in blowdown streams 

discharged to POTW's can be controlled. This can be achieved 

by one of the following methods: 

Regulation through feedback instrumentation; 

Splitting the condenser effluent into two streams 

and chlorinating one at a time; 

o Reducing the length of the chlorination period; 

@ Substituting ozonation for chlorination. 

A number of advantages of ozonation over chlorination for 

the disinfecting of water have been recently cited. These 

advantages can be summarized as follows: 1) ozone neither 

increases the inorganic salt content nor produces pollutants 

after reactions; 2) ozone does not impart taste, color, or 

smell to the treated water; 3) ozone is a much more powerful 

disinfectant than chlorine; 4) ozone does not have any known 

harmful effect on aquatic life; and 5) ozone does not have 

undesirable residual effects as it readily breaks down into 

oxygen. 

Chlorination, on the other hand, is now being questioned by 

health authorities who must meet increasingly stringent 

bacteriological and waste discharge requirements. An 

increased chlorine dosage which may provide satisfactory 

disinfection requirements may also be responsible for 
DRAFT 

release of an excessive amount of polluting material to 

the aquatic environment. Current reports show that even 

trace amounts of chlorine are harmful to aquatic life (12). 

Water Treatment Wastes. Substitution of reverse 

osmosis or electrodialysis for ion exchanqe to produce 

boiler feed water will- greatly reduce thewdischarge from 

this section of the process. However, the technical feasibility 

of the reverse osmosis process is limited by the chemical 

characteristics of the raw water source and by economics, 

and for some plants polishing the product water by ion 

exchange will still be necessary, depending on the boiler 

operating pressure. 

A substantial reduction in wastewater can also be achieved 

by preparing boiler feed water in a combined system consisting 

of the hot lime and the ion exchange processes (12). The 

raw water would be initially softened by the hot lime process 

to remove a portion of the dissolved matter and then deionized 

in an ion exchange system. Because of the reduced dissolved 

matter load on the ion exchanges the system would have to be 

regenerated less frequently, and consequently, would generate 

less wastewater. Combined systems consisting of hot lime and 

zeolite deionization processes are used by plants 9369, 7116, 

and 6387. 

Ash Handling Wastes. Ash handling is the conveyance of the 

accumulated bottom and fly ash combustion solid waste product 

to a disposal system. This is accomplished by dry or wet 

processes. In the dry process the ash is transported to the 

disposal area by pressurized air, vacuum, or mechanical means. 

Dry ash handling systems do not generate wastewater and may 

allow a credit for the sale of the ash for its metal content. 

Bottom ash from oil fired furnace, for example, can be sold 

for its vanadium content. 

The wet process can be either open or closed-loop systems. 

In the closed-loop system the ash is slurried in water and 

conveyed to a clarifier where settling occurs. The clarified 

overflow from the settling pond is returned to the boiler. 

The closed-loop ash handling system does not generate 

wastewater except in areas of excessive rainfall where the 

system must be periodically bled. In such cases the blowdown 

must be treated in a separate system to remove metal ion by 

precipitation and suspended solids by clarification. In 

areas where the rate of evaporation is higher than the rate 

of precipitation, evaporation losses from closed-loop ash 

handling systems can be supplemented with wastewater from 

other unit processes such as cooling tower blowdown. 

Open-loop ash handling systems are a source for wastewater 
DRAFT 

since the transporting water is used but once to convey the 

ash to the settling ponds. This wastewater source can be 

eliminated by switching to dry or closed-loop type systems. 

Open-loop ash handling systems should be avoided when 

possible as the effluent from the ash pond may require 

additional treatment before it can be discharged. 

-- Coal Pile Runoff. The extent of contamination of coal 

pile runoff can be reduced by properly constructing the coal 

storage area. Coal piles can be sprayed with tar or covered 

with plastic sheeting to seal the surface to water infiltration 

A drainage system should be constructed to collect the most 

polluted portion of the storm. In areas where the rate of 

evaporation is higher than the rate of precipitation runoff 

can be disposed of by evaporation in ponds. Alternatively, 

coal pile drainage can be used in processes which tolerate 

low quality waters such as ash handling systems. If the 

plant is located near a mine such water can be used in the 

coal washers to remove mineral matter. Diversion of this 

waste to ash ponds was also considered. However, because 

of the low pH of such wastes, coal ash can be leached by 

the water resulting in the formation of additional waterborne 

pol 1 utants. 

Air Pollution Control Scrubbing Devices. The nonrecovery scrubbing process for SO2 removal from flue gas is 

also a sourc-e of wastewater as the system may be periodically 

bled to remove spent solvent. This is a closed-loop type 

system employing recycled lime scrubbing liquor. The process 

requires makeup water for saturating the boiler gases. 

Changing to SO2 recovery systems would reduce the discharge 

from this part-of the process as well as allow a credit for 

the sale of recovered sulfur dioxide or other sulfur products. 

Table VII-6 lists some of the SO2 recovery processes currently 

available. It should be emphasiled, however, that some of 

the listed processes have reached only the pilot plant stage 

of their development and cost estimates for their installation 

and operation are somewhat higher than those for the nonrecovery processes. 

Material Substitution 

The blowdown from a recirculating cooling system can be 

reduced by increasing the concentration cycle. This can be 

achieved by substituting scale-forming ions with more soluble 

ions, or by using sequestering agents such as polyolesters 

and phosphonates to prevent deposition of precipitated solid 

phases. These dispersing agents, however, become pollutants 

in the blowdown water. 
Table VII-6. RECOVERY PROCESSES FOR FLUE GAS DESULFURIZATION SYSTEMS 

Process 

1. Double alkali 

sys tem 

2. Chemilbau 

sys tem 

Hydrogen sul fi te 

system 

Wellman-Lord 

sys tern 

Ca t-Ox - sys tern 

Shell flue gas 

system 

Mode of SO2 - 

Sorbent System Removal Sul fur Recovery Product 

Aqueous solution of Chemical Precipitation of Calcium sulfate 

Sodium hydroxi de, absorption dissolved sulfur Calcium sulfi te 

Sodium sulfate, & oxides with 

sodium b i s u l f i t e CA(OH)2 -

Fluidized bed of Catalytic oxidation Thermal stripping Sulfur, liquid 

activated carbon to ~c04 

and Fhysical 

absorption 

solutionof sodium Chemical 

ci trate, citric absorption 

acid and sodium 

thiosul fate 

Aqueous solution Chemical 

of sodium sulfate absorption 

and sodium 

bisulfite 

Catalytic 

oxidation of 

SO2 to SO3 with 

02-at 850~~ 

(vanadium oxide) 

A bed of cupric Oxidation to 

oxide supported by cupric sulfate 

activated 

a 1 umi na 

with hydrogen at SO2 

1000°F and 

catalytic reduction 

with H2S - 

Precipitation of Sulfur 

dissolved sulfur 

with H2S - 

Thermal Sulfur 

regeneration by 

vacuum and 

catalytic reduction 

with natural gas 

78% sulfuric acid 

Concentrated 

S 02 - 
DRAFT 

Lime softening of cooling water makeup prior to its introduction 

into the system would also increase the concentration cycle, 

though it may be costly because of large volumes of water 

requiring treatment. 

Installation of plastic or plastic-coated system components 

would reduce the extent of treatment of cooling water makeup. 

Plastic exhibits considerable resistance to corrosion and 

erosion. Many new installations using cooling towers employ 

plastic. 

Where publicly-owned treatment plants containing a tertiary 

step are used, phosphate and nitrate based corrosion inhibitors 

could be substituted for chromates as these pollutants are 

removed by a tertiary treatment step. Chromate-based compounds 

can also be substituted by a re~ently~developed synthetic 

organic corrosion inhibitor which is not as toxic as chromate 

to microorganisms. The synthetic organic compound reduces 

both scaling and fouling as well as inhibits corrosion (12). 

Film-forming sulfophosphated organic corrosion inhibitor has 

also been developed. The substance is effective in both 

fresh and salty water, and is also considerably less toxic 

than chromate (12). 

To reduce the amount of metals in wastewater from cooling 

system blowdown and from chemical cleaning operations, 

boilers and condenser cooling systems could be constructed 

of non-polluting materials. Tubes and piping could be made 

of special alloy metals or coated so as to reduce corrosion 

and scaling, but this can be prohibitively costly. Cooling 

towers can be constructed out of concrete and ceramic 

materials and thus reduce the need for additives to the 

cooling water system. Pollutants contained in fireside wash 

can be modified by switching fuels. The switch from coal to 

low-sulfur oil is an example of such modification. 

Switching to low sulfur fuels can also eliminate the need 

for air pollution control devices. Switching to gaseous and 

liquid fuels eliminates the problems of ash disposal and 

coal pile runoff waters. 

Water Conservation and Wastewater Reuse 

Different water uses in the plant require water of widely 

varying quality. These range from the almost zero solids 

requirements for boiler feedwater makeup to the almost 

unlimited solids allowed for ash transport water or scrubber 

water supply. Consequently, the wastewater produced in the 

plant also vary widely in quality. This opens many opportunities 

for wastewater reuse. 
DRAFT 

Cooling system blowdown can be reused for ash transport or 

as scrubber water supply. Boiler blowdown water is usually 

better than the feed water supply and can be reused in 

the plant for other purposes. 

Boiler blowdown can be reduced by installing a heat recovery 

system. In such a system the blowdown is discharged into a 

flash tank operating at a lower pressure than the boiler 

pressure. Because of the reduced pressure a portion of the 

blowdown water evaporates to form low pressure steam which 

can be condensed and reused as boiler feedwater. The 

reduction in blowdown that can be achieved by this method 

depends on the pressure difference between the boiler and 

the flush tank. The use of a heat recovery system for 

boiler blowdown will also increase the thermal efficiency of 

the plant. 

Spent regenerants and rinses from the ion exchange system 

are also of a quality suitable for many purposes, where 

dissolved solids are not a limiting factor. 

Some of the periodic waste streams could be recycled or 

reused if sufficient storage is available to hold these 

streams until needed. Metal cleaning wastes after pretreatment or treatment could be used for low quality water 

uses such as ash transport or scrubber supply. However, the 

cost of storage may make such reuse prohibited. 

Materials Recovery 

Nearly all chromates, used as corrosion inhibitors, can be 

recovered using properly designed ion-exchange beds. 

Regenerant streams from the beds, which contain a relatively 

high c,oncentration of chromate, can be returned to the 

cooling system as a usable corrosion inhibitor. Plants which 

soften boiler feedwater with lime can reuse lime sludge in 

their air pollution control system for SO2 - removal. 

Recoverying-heat from boiler blowdown would reduce thermal 

discharges from this segment of the process, as well as 

increase the thermal efficienty of the process. Recycling 

of fly ash back to the furnace can be employed to increase 

thermal efficiency by burning products of incomplete 

combustion. It is also possible to recover vanadium from 

oil ash with high vanadium content. Spent regenerants from 

ion exchange system can be used where the quality of the 

acid and alkaline solutions is not critical. For example, 

the acid solutions can be used in recirculating cooling 

system to maintain the pH of the water below saturation. 

Air pollution control devices, on the other hand, may require 

an alkaline source of water. 
DRAFT 

Good .Housekeeping Practices 

There are numerous alternative methods ranging from taking 

precautionary measures against spi 11 s of chemical solutions 

or oil to pump sealing to prevent leaks. Facilities should 

be constructed so that oil and grease contaminated water 

will not drain directly into other water systems or be 

diluted by rainfall runoff. Cleaning up oil spills, maintaining 

equipment to minimize leaks, and supporting an effective 

surveillance program wi 11 a1 so minimize contamination of 

wastewater effluents. Controlling additions of chemicals 

to waters used in the various units of the process would 

reduce thei r concentrations in the effluents streams. Flow 

of water into the plant should be regulated in accordance 

with production rate. 

SUMMARY 

A variety of wastewater control and treatment technologies 

are available for the steam electric power industry. Since 

the water needs, and the requirements for wastewater discharge 

are specific to each individual plant, each control and 

treatment system must be developed in accordance with the 

individual plant requirement and should be integrated in a 

comprehensi ve water management program. Special consideration 

should be given to in-process control techniques. Often, 

such technique can be found easy and inexpensive to implement 

and yet, they can result in substantial reduction in water 

consumption and wastewater discharge. 
DRAFT 

SECTION VIII 

COST, ENERGY, AND OTHER NONNATER 

QUALITY ASPECTS 

INTRODUCTION 

This section discusses cost estimates for control and 

treatment technologies described in previous sections, 

energy requirements for these technologies, and nonwater 

quality related aspects such as reuse of water within the 

plant. Ultimate disposal of brines and sludges, effect of 

1 and avai 1 abi 1 i ty, user charges and pol 1 utants 1 imitations 

imposed by POTWs and other factors relating to the steam 

electric power generating point source category are also 

discussed in this Section. 

Costs are developed in greater detail for those waste 

sources which potentially are discharged to POTWs and are 

therefore subject to pretreatment requirements. These 

include the following: 

o Low Vol ume Wastes 

o Metal Cleaning Wastes 

a Cooling Tower Blowdown 

a Area Runoff and Ash Pond Discharges 

Other waste streams such as ash transport water, boiler 

blowdown, and once-through cooling water are provided in 

the latter part of this section. 

The raw waste characteristics for discharges to POTWs are 

similar to those for direct discharge to surface water, as 

covered in the Development Document for this industrial 

category. 
DRAFT 

For most power plant wastes, the pretreatment for discharge 

to POTW involves control of three parameters of pollution, 

pH, suspended solids, and oil and grease. Control of pH 

neutralizes any undesirable acidity or a1 kalinity. 

Treatment for suspended solids then removes suspended 

metals as well as other suspended material. Oil and grease 

is separated from the water phase of the low volume wastes 

and skimmed off. 

COST REFERENCES -- AND A RATIONALE 

Cost information contained in this report was obtained from 

the following sources: 

o Engineering estimates based on published cost 

data for equipment, construction, and 

instal lation; 

o Estimates and guidelines for estimating 

contained in the Development Document 

for steam electric industry discharges to 

surface water and the other EPA documents; 

o Quotations for materials and supplies 

pub1 ished in current trade journals. 

o Cost.data obtained as a result of direct 

inquiry to industry for data on actual 

installations. 

Interest Rates and Equity Finance Charges 

Capital investment cost estimates for this study have been 

based on 10 percent capital cost which represents a 

composite value for either interest rate paid or the 

required return on .investment. 

---- Time Basis for Cost Adjustment 

All estimated costs are taken from July, 1976 prices or 

where necessary adjusted to this time basis using the ENR 

construction cost index of 2413 (July 1, 1976). 

-- Useful Service Life 

The useful service life of all wastewater treatment and 

disposal facilities is a function of the process involved, 

the quality of the equipment and design, its use patterns, 

the quality of maintenance and several other factors. 

Whereas individual companies often use service 1 i ves based 

on actual local experience, for the purpose of internal 

authorization, the Internal Revenue Service provides 
DRAFT 

guideline for tax computational purposes which are intended 

to reflect approximate average 1 i fe experience. 

The following useful service life values were chosen 'for use 

in this report from the literature, discussions with 

representatives of industry, and IRS guide1 ines data: 

0 General process equipment 10 years 

e Bui ldings, sewers, ponds, etc. 20 years 

e Material handling equipment and 5 years 

vehicles 

Depreciation 

The allocation of the cost of capital assets such as 

treatment and disposal equipment less salvage (if any) over 

the estimated useful service life of the unit or facility in 

a systematic and rational manner as a non-cash expense is 

termed depreciation. For IRS tax purposes and to make 

suitable financial allowance for equipment replacement 

several types of depreciation are used. Simple straightline 

depreciation was used as the basis of calculations in this 

report. 

Capital Costs 

Capital costs have been defined for this study as all 

initial out-of-pocket cash expenditures for provision of 

wastewater treatment and disposal facilities. These costs 

will include research, development, and feasibility studies 

necessary to characterize and design the facilities land and 

site preparation costs when applicable, equipment, construction, 

installation, and start-up costs, costs of buildings, 

services and engineering (allocated where necessary), 

contractor profits and contingency costs if such exist. 

Annual Capital Costs 

Most capital costs are accrued during the year or two prior 

to actual use of the facility. This present worth sum can 

be converted to equivalent uniform annual disbursements over 

the life of the facility by utilizing the Capital Recovery 

Factor Method: 

Uniform Annual Disbursement = 

where P = present value (capital expenditure) , i = interest rate, %/I03 

n = useful life in years 
DRAFT 

Operating Expenses 

Annual costs of operating pretreatment facilities include 

labor, supervision, materials, maintenance, taxes, .insurance, 

and power and energy. Operating costs combined with 

annualized capital costs give total costs for pretreatment 

operations. 

Rationale for Model Plants 

Plant costs are estimated for model plants rather than for 

any actual plant. Model plants are defined to have sizes of 

25 MW and 500 MW capacity, which are representative of large 

and small-sized operation. 

Definition - of Levels - of Treatment and Control 

Costs are developed for various types and levels of technology: 

Minimum (A -- or basic level). That level of technology which 

is equalled or exceeded by most or all of the involved 

plants. 

Usually, money for this treatment level has already been 

spent (in the case of capital investment) or is being spent 

(in the case of operating and overall costs). 

B,C,D--Levels. Successively greater degrees of treatment 

with respect to critical pollutant parameters. Two or more 

a1 ternative treatments are developed when applicable. 

Basis for Pretreatment Costs 

In development of cost estimates found in Tables VIII-1, 

VIII-2, VIII-4, and VIII-5, it is assumed that only the 

following wastewater effluents are discharged to POTWs and 

may, therefore, require pretreatment. 

o Low Volume Wastes 

o Metal Cleaning Wastes 

Cooling Tower Blowdown 

o Area Runoff and Ash Pond Discharges 

0 

Low volume wastes include ion-exchange regenerants, spills, 

leaks, air pollution control system bleed offs, area 

washdowns, and other miscellaneous wastewater streams. 

Metal cleaning wastes include tube and fireside boiler 

cleaning products, as well as air cleaner wastes. 
DRAFT 

Area runoff includes rainwater runoff from coal piles. 

Ash pond overflows and blowdowns are designated as 

discharges. 

Costs have been addressed separately for the following wastes: 

Ash Transport Water 

Boi 1 er Bl owdown 

Reasons for addressing these sources of wastes separately 

are discussed in detail in Section VII, but are also 

discussed briefly below. 

Ash transport water from coal-fired plants is generally 

recirculated after sedimentation, and the purpose of 

sedimentation is process rather than pollution control. 

Overflows from ash ponds are included in the wastewater for 

pretreatment. 

Boiler blowdown can be, and sometimes is, discharged to POTW 

without pretreatment. In can be handled at the combined 

plant without incremental costs. 

No plant contacted in this study was found to discharge 

once-through cooling water to a POTW. Therefore, costs are 

not generated for pretreatment requirements. 

Cost Variances 

The effects of age, location, and size on costs for 

treatment and control have been considered and are in the 

body of this section. 

COSTS FOR PRETREATMENT 

Waste types covered in this subsection include low volume 

wastes, metal cleaning wastes, cooling tower blowdown, area 

runoff and ash pond discharge. Since the wasteload differs 

depending on the fuel source used, cost estimates for 

pretreatment of wastewater effluents from steam electric 

plants have been divided into those plants burning gas or 

oil and those using coal. 

--- Oil and Gas Fired Plants 

Oil and gas-fired plants probably will have no ash pond 

discharge, no air pollution control wastewater, or coal pile 

runoff. Therefore, these plants have essentially ion-exchange 
regenerants, miscellaneous low volume wastes, cooling tower 

blowdown and metal cleaning wastes. 

Estimated wastewater volumes in literslday (GPD) for the 

plant sizes given are: 

25 MW Plant 500 MW Plant 

@ Low Volume Wastes 

Ion-exchange re 

generants 11,400(3000) 454,000(120,000) 

Miscellaneous 3,800(1000) 151,400( 40,000) 

0 Metal Cleaning 

Wastes 380 ( 100) 10,200( 2,700) 

@ Cooling Tower 

Bl owdown 94,600(25,000) 1,892,000(500,000) 

The low volume wastes contain primarily acids and/or bases 

and perhaps some oil. The metal cleaning wastes contain 

acids, bases, metals, oil and grease, and suspended solids. 

Cooling tower blowdown may contain chromates, chlorine, 

chlorinated phenols, mercury, phosphate, zinc and many other 

additives commonly used in cooling tower systems. For 

purposes of cost analysis, however, cooling tower blowdown 

is assumed to contain only free chlorine (chlorine is the 

most commonly reported biocide used). 

Defined Pretreatment Levels 

The raw wastes requiring pretreatment prior to POTW disposal 

are similar to those described in the Development Document 

for direct dischargers, and use has been made of the data on 

wastewater volumes, waste loads and other information 

contained therein. The minimum pretreatment level, defined 

as Level A, consists of that level of technology which is 

equalled or exceeded by most or all of the existing plants. 

This level involves some flow equalization and combining of 

wastes to get the benefit of some neutralizing and diluting 

effects. Expenditures, both capital and operating are small. 
DRAFT 

WASTEWATER TREATMENT COSTS AND RESULTING 

WASTE-LOAD CHARACTERISTICS FOR f YPlCAL PLANT 

s"ecATEGoRY Oil or Gas Fired Plant 

PLANT SIZE 25 MW 

-- --- ---------- 

PLANT AGE -. YEARS PLANT LOCATION 

COSTS OF TREATMENT TO ATTAIN SPECIFIED LEVELS 

RLSULTIWI WASTE-LOAD CHARACTERISTICS 

COST CATE00RY 

TOTAL INVESTED CAPITAL 

ANNUAL CAPITAL RECOVERY 

ANNUAL OPERATtNO AND YAlHTENANCE 

COSTS (EXCLUDINB EIUEROY AND POWER) 

ANNUAL ENLRIY AWD POWER COSTS 

TOTAL ANNUAL COSTS 

t [ COSTS [#I Mi 1 s/KWH* 1 0.008 1 0.097 1 0.124 1 0.186 1 

*Plant operating at full capacity and 7500 hrs/yr. 

cosss (U 10 ATTAIN LEVEL 

I 

PARAMETER 

A 

10,000 

$1,600 

Small 

Small 

1,600 

,(a TSS 

F e 

(a) Low volume and metal cleaning wastes combined 

(b) Cool i ng Tower Bl owdown 

NOTE: TSS, Fe, and Cu, raw wastes concentrations estimated from Table A-V-20 

of Development Document EPA 44011-74029 a (12) 

A 1 8 C D 1 E 

j 

CONCENTRAT ION (mg/l) (~)nl 

,Oil & Grease 

(b) Free CL? 

Level A - 

Level B - 

Level C - 

Level D - 

B 

50,000 ' 

8,150 

10,000 

Small 

18,150 

RAW 

(UNTREATED) 

300 

200 

. . 

Flow Equal ization 

Equalization of low volume wastes, followed by neutralization 

to pH 6-9, skimming of surface oil. Metal cleaning wastes combined 

with lo& volume wastes and neutralized without sludge removal. 

Same as Level B except metal cleaning wastes neutralized, clarified 

with sludge removal and discharged. 

Equalization, pH ad.justment, oil skimming, clarification, reacidification. Cooling tower blowdown treated with sulfi te. 

AFTER TRLATYENT TO LEVEL 

---- 

0.5 

C 

60,000 

9,760 

13,000 

500 

23,260 

300 

200 

---- 

0.5 

D 

120,000 

19,500 

15,000 

500 

35,000 

300 

200 

E 

100 

0.5 

100 

< 1.0 

<I00 

<l .O 

< 100 

0.5 

<I00 

0.0 
DRAFT 

TABLE VIII-2 

WASTEWATER TREATMENT COSTS AND RESULTING 

WASTE-LOAD CHARACTERISTICS FOR TYPICAL PLANT 

PLANT SIZE 500 MW 

---- ------------ 

PLANT AGE . YEARS PLANT LOCATION 

COSTS OF TREATUENT TO ATTAIN SPECIFIED LEVELS 

COST CATEOOAY 

cosrs<U TO ATTAIN LEVEL 

TOTAL INVEST ED CAPITAL 

ANNUAL CAPITAL RECOVERY 

ANNUAL OPERATINO AH0 MAINTENANCE 

COSTS (EXCLUDIWO ESEROY AND POWER) 

ANNUAL ENLROY AND POWER COSTS 

RESULTII(0 WASTE-LOAD CHARACTERISTICS 

A 1 8 1 C 1 0 1 E I 

TOTAL ANNUAL COSTS 

80,000 

13,000 

1 

Small 

(a) Low volume and metal cleaning wastes combined 

(b) Cooling Tower Blowdown 

NOTE: TSS, Fe, and Cu, raw wastes concentrations estimated from Table A-V-20 

of Development Document EPA 440/1-74029 a (12) 

Level A - Flow Equalization 

Level B - Equalization of low volume wastes, followed by neutralization 

to pH 6-9, skimming of surface oil. Metal cleaning wastes combined 

with low volume wastes and neutralized without sludge removal. 

Level C - Same as Level B except metal cleaning wastes neutralized, clarified 

with sludge removal and discharged. 

Level D - Equalization, pH adjustment, oil skimming, clarification, reacidification. Cooling tower blowdown treated with sulfi te. 

13,000 

PARAMETER 

(a) TSS 

F e 

Cu 

P H 

Oil & Grease 

(b) Free CL7 

700,000 

114,000 

130,000 

3,000 

300,000 

48,800 

60,000 

1,000 

COSTS 4. Mi 1 s/KWH* 

109,800 

300.000 

48,800 

80,000 

2,000 

*Plant operating at full capacity and 7500 hrs/yr. 

0.035 

i 

CONCENTRATION (ng/l) (ppn) 

0.004 

130,800 

RAW 

tunTREATED) 

300 

200 

1 .o 

----- 

----- 

0.5 

0.029 

2479000 

0.065 J 

AFTER TREATMENT TO LEVEL 

A 

300 

200 

1 .o 

------ 

------ 

0.5 

8 

300 

200 

1 .o 

6-9 

100 

0.5 

c 

100 

<1 .O 

<I -0 

6-9 

<I00 

0.5 

D 

<I 00 

< 1.0 

< 1 .o 

6-9 

<I 00 

0.0 

E 

- 

I 
DRAFT 

Level B pretreatment involves equalization of low volume 

wastes, neutralization to a pH 6-9 and skirnmipg of surface 

.oil. Metal cleaning wastes are stored in a large tank or 

small pond and fed slowly to the neutralization tank for 

small volume wastes and boiler blowdown. There is no 

sludge removal on pretreatment of cooling tower blowdown. 

Level C pretreatment is the same as Level B except that 

the metal cleaning wastes are neutralized, clarified 

and discharged. Provision is made for sludge removal. 

L.eve1 D pretreatment is essentially that for BPCTCA for 

direct discharge to surface water. For this level all waste 

st-reams with exception of the cooling tower blowdown are fed 

into a tank for pH adjustment (optimum in the 9-11 pH 

range), oil is skimmed from the liquid surface, and 

suspended solids are removed in a clarifier. Acid is then 

added to reduce pH to 6-9 prior to discharge. Cooling tower 

blowdown is treated separately with sulfite to remove free 

chlorine. 

Costs and estimated effluent concentrations achieved for oil 

and gas-fired plants are given in Table VIII-1 and VIII-2. 

Detailed model description for bevel D is given in the 

following subsection. 

Costs for Levels A, B, and C are roughly estimated from cost 

experience with similar wastewater volumes and compositions 

in other industries as well as from steam electric power 

plants. 

Capital cost data for wastewater pretreatment facilities for 

oil and gas-fired steam electric power plants discharging to 

public sewerage systems are summarized in Table VIII-3. 

Table VIII-3. SUMMARY OF CAPITAL COSTS OIL AND GASFIRED PLANTS 25 MW PLANT 

$ Per KW IGC 

Pretreatment Technology Level 

Category 

Low Volume Wastes 0.38 1.20 1.20 1.60 

Metal Cleaning Wastes 0.02 0.80 1.20 1 .O 

Cooling Tower Blowdown NT NT NT 1.66 

Boi ler Blowdown NT NT NT 0.54 

TOTAL COST 
DRAFT 

Table VIII-3. (CONT'd) 

Category 

500 MW Plant 

$ Per KW IGC 

Pretreatment Technology Level 

Low Vol ume Wastes 0.15 0.50 0.50 0.79 

Metal Cleaning Wastes 0.01 0.10 0.10 0.20 

Cooling Tower Blowdown NT NT NT 0.31 

Boi 1 er Bl owdown NT NT NT 0.10 

TOTAL COST 0.16 0.6 0.6 1.40 

Note: NA not applicable to discharge to POTW 

NT Not treated 

A - Flow equalization. 

B - Equalization and neutralization of low 

volume wastes to pH 6-9, skimming of 

surface oil. Metal cleaning wastes 

combined with low volume wastes and neutralized 

without s1 udge removal. 

C - Same as Level B except metal cleaning 

wastes neutralized, clarified and 

discharged. Provision is made for sludge 

removal. 

D - Equalization, pH adjustment, oil skimming, 

reacidification, clarification. Cooling 

tower blowdown treated with sul fite. 

Coal-Fired Plants 

Coal-fired plants have ash pond discharges, air pollution 

control wastewater, coal pile runoff, ion-exchange 

regenerants, miscellaneous low volume wastes, cooling tower 

blowdown and metal cleaning wastes. 

Estimated wastewater volumes in liters/day (GPD) for the 

plants sizes given are: ' 

Low Volume Wastes 

- Air Pollution Wastes 3800 (1000) 151,400 (40,000) 

- Ion Exchange Regenerants 11400 (3000) 454,000 (1 20,000) 

- Mi scell aneous 3800 (1000) 15,400 (40,000) 

a Metal Cleaning Wastes 380 ( 100) 10,200 ( 2,700) - 
DRAFT 

o Cooling Tower 94,600(25000) 1,892,000(500,000) 

Bl owdown 

Area Runoff 3,800( 1000) 94,600( 25,000) 

o Ash Pond Discharge 3,800( 1000) 75,700( 20,000) 

The low volume wastes contain primarily acids bases and 

suspended solids. The metal cleaning wastes contain acids, 

bases, metals, and suspended solids. Cooling tower blowdown 

as discussed for oil and gas-fired plants may contain a 

variety of additives but for purposes of this cost 

development is assumed to contain only free chlorine. Area 

runoff contains acid, suspended solids and possibly some 

metals. Ash pond discharges contain suspended and dissolved 

solids. 

The minimum level for pretreatments, defined as Level A, 

consists of that level of technology which is equalled or 

exceeded by most or all of the existing plants. This level 

involves some flow equalization and neutralization resulting 

from the combination of waste streams of differing pH. 

There is no control or treatment of runoff. Expenditures, 

both capital and operating are small. 

Level B pretreatment involves equalization of low volume 

waste streams, neutralization to pH of 6-9. Metal cleaning 

wastes are stored in a large tank or small pond and fed 

slowly to the treatment system for low volume wastes. 

There is no control of area runoff. 

Level C pretreatment is the same as Level B except that 

the metal cleaning wastes are neutralized, clarified and 

discharged. Provision is made for the sludge removal. 

Level D pretreatment involves technology that will in 

general meet the requirements of BPCTCA for direct discharge 

to surface water. For this level area runoff from coal 

piles and ash transport water overflow are retained in a 

pond and fed continuously to a central pretreatment system. 

Metal cleaning wastes are similarly retained and fed 

continuously to the system. The pretreatment system itself 

is described in a following subsection. It consists 

primarily of a tank for pH control and oil skimming and a 

clarifier for suspended sol ids removal. 
DRAFT 

Costs and effluent quantities for the four treatment levels 

for coal-fired plants are summarized in Tables VIII-4 and 

VIII-5. Costs for Level D are developed in a following 

subsection. 

Capital cost data for wastewater pretreatment faci 1 i ties for 

coal -fired steam electric power plants discharging to pub1 ic 

sewerage systems are summarized in Table VIII-6. 

--- Model Pretreatment Plants - Level D Technology - 

Model pretreatment plant costs have been developed for power 

plants of 25 MW and 500 MW capacity of combined pretreatment 

facilities for low volume and metal cleaning wastes. 

Separate cost estimates are presented for treatment of area 

runoff and ash transport water discharge. 

Estimates are for national average costs and do not consider 

regional differences in construction costs. All estimates 

are based on the following technology: pretreatment for pH 

adjustment to between 6.0 and 9.0, flow equalization so that 

the instantaneous peak discharge does not exceed five times 

the monthly average flow rate, reduction of suspended solids 

to POTW limitations, and removal of biocides, oil and grease 

and metals to levels specified in the effluent limitation 

guide1 ines regulations. 

Estimated operating costs are presented for centralized 

pretreatment facilities for each model plant size. Operating 

costs include labor, fuel and power, chemicals, maintenance, 

residue removal and management. Actual operating costs may 

vary widely for those shown herein because of variations in 

processes, degree of automation, and allocation of joint 

labor costs. 

The model waste treatment plants which form the basis of the 

cost estimates are designed to provide Level D treatment for 

low volume wastes and metal cleaning wastes from coalfired plants. Ash transport water or ash pond overflows are 

not included in the cost basis. Combination of cooling 

water system blowdown with low volume and metal cleaning 

wastes is not desirable, since cooling tower blowdown is a 

continuous operation requiring minimal treatment. Low 

volume and metal cleaning wastes are intermittently produced 

and require flow equalization and more intensive treatment. 

Plants discharging cool i ng water system bl owdown to the 

public sewer will have to add the cost of required 

pretreatment of cooling system blowdown to the cost of the 

pretreatment of the low volume and metal cleaning wastes. 
DRAFT 

TABLE 1111-4 

WASTEWATER TREATMENT COSTS AND RESULTING 

WASTE-LOAD CHARACTERISTICS FOR TYPICAL PLANT 

PLANT SIZE 7.5 MW 

PLANT AGE - - " YEARS PLANT LOCATION '---"---" 

COSTS OF TREATMENT TO ATTAIN SPECIFIED LEVELS 

COST CATEOORY 

, 

TOTAL INVLSTED CAPITAL I 

ANNUAL CAPITAL RECOVERY 

ANNUAL OPERATINO AND MAINTENANCE 

COSTS (EXCLUDINQ ENERQY AND POWER) 

ANNUAL EMEROY AND POWER COSTS 

RtSULTUI@ WASTE-LOAD CHARACTERISTICS 

- 

TOTAL ANNUAL CCSTS 1 3,250 

COSTS(O) to ATTAIN LEVEL 

27,200 1 33,100 1 46,800 

(a) Low volume and metal cleaning wastes combined 

(b) Cool i ng Tower Bl owdown 

NOTE: TSS, Fe, and Cu, raw wastes concentrations estimated from Table A-V-20 

of Development Document EPA 440/1-74029 a (12) 

Level A - Flow Equalization 

Level B - Equalization of low volume wastes, followed by neutralization 

to pH 6-9, skimming of surface oil. Metal cleaning wastes cmbined 

with low vol ume wastes and n~ut ral i zed without s1 uAqe removal . Level C - Same as Level B except metal cleaning wastes neutralized, clarified 

with sludge removal and discharged. 

Level D - Equalization, pH adjustment, oil skimming, clarification, reacidification. Cooling tower bl owdown treated with sulfi te. 

COSTS Mi 7 s/KWH* 1 0.017 0.145 1 0.176 1 0.249 j I 

*Plant operating at full capacity and 7500 hrs/yr. 

PARAMETER 

(a) TSS 

Fe 

C u 

pH 

Oil & Grease 

-- 

(b) Free C12 

D 

143,000 

23,300 

20,000 

500 

C 

90,000 

14,600 

18,000 

500 

A 

20,000 

3,250 

Small 

Small 

CONCENTRATION (mg/l) (wm) 

B E 

75,000 

12,200 

15,000 

Small 

RAW 

WNTREATED) 

300 

150 

0.7 

---- 

- - - - - 

0.5 

AFTER TREATMENT TO LEVEL 

A 

300 

150 

0.7 

------ 

------ 

0.5 

E 

A 

9 

300 

150 

0.7 

6-9 

4 100 

0.5 

c D 

< 100 

<.1 .O 

0.7 

6-9 

< 100 

0.5 

< 100 

<lo 

0.7 

6-9 

<I00 

0.0 
DRAFT 

VIII-5 

WASTEWATER TREATMENT COSTS AND RESULTING 

WASTE-LOAD CHARACTERISTICS FOR TYPICAL PLANT 

SUBCATEGORY Coal Fired Plant 

PLANT SIZE 500 MW 

----- ---------- 

PLANT AGE , YEARS PLANT LOCATION 

COSTS OF TREATMENT TO ATTAIN SPECIFIED LEVELS 

- - - 

*Plant operating at full capacity and 7500 hrslyr. 

RLSUMIWI WASTE-LOAD CHARACTERISTICS 

COST CATEOORI 

TOTAL INVLSTED CAPITAL 

AUNUAL CAPITAL RECOVERY 

ANNUAL OPERATINO AND YAINTENANCE 

COSTS (EXCLUDINO ENEROY AND POWER) 

ANNUAL EYIRIY AND COWER COSTS 

TOTAL ANNUAL COSTS 

I 

I I CoNc~NTnAT~o~ (ma/l) (mn) 

(a) Low volume and metal cleaning wastes combined 

(b) Cooling Tower Blowdown 

NOTE: TSSy Fe, and Cu, raw wastes concentrations estimated from Table A-V-20 

of Development Document EPA 440/1-74029 a (12) 

Level A - Flow Equalization 

Level B - Equalization of low volume wastes, followed by neutralization 

to pH 6-9, skimming of surface oil. Metal cleaning wastes combined 

with low volume wastes and neutral ized without sludge removal. 

Level C - Same as Level 6 except metal cleaning wastes neutralized, clarified 

with sludge removal and discharged. 

Level D - Equalization, pH adjustment, oi 1 skimming, clarification, reacidification. Cooling tower bl owdown treated with sulfi te. 

cosrs(t) ro ATTAIN LEVEL - 

A 

~~~Y~~~ 

16,300 

Sma 1 1 

Small 

16,300 

COSTS Mi 1 s/KWH* I 0.004 1 0.035 1 0.041 0.078 1 

B 

350,000 

57,000 

70,000 

2,000 

129,000 

C 

350,000 

57,000 

93,100 

2,500 

1 152,600' 

0 

7903000 

128,500 

163,800 

3,000 

295,300 

E 
DRAFT 

Table VIII-6. SUMMARY OF CAPITAL COSTS COAL FIRED PLANTS 

Category 

Low Volume Wastes 

Metal Cleaning Wastes 

Cool i ng Tower Bl owdown 

Area Runoff 

Ash Handling Wastes 

Boi 1 er Bl owdown 

25 MW Plant 

$ Per KW IGC 

Pretreatment Technology Level 

TOTAL COST 

Category 

Low Vol ume Wastes 

Metal Cleaning Wastes 

Cool i ng Tower Bl owdown 

Area Runoffs 

Ash Pond Discharges 

Boi 1 er Bl owdown 

TOTAL COST 

500 MW Plant 

NOTE: NA - Not app 11 icable to discharge to POTI 

NT - Not treated 

LEVELS OF PRETREATMENT 

A - Flow Equalization 

B - Equalization and neutralization of low volume wastes to 

pH 6-9 skimming of surface oil. Metal cleaning wastes 

combined with low volume wastes and neutralized without 

sludge removal. 

C - Same as Level B except metal cleaning wastes neutralized, 

clarified and discharged. Provision is made for sludge 

removal . D - Equalization, pH adjustment, oil skimming, clarification, 

reacidification. Cooling tower blowdown treated with 

sulfite. 
DRAFT 

Power plants sizes selected for model treatment plants are 

25 MW and 500 MW. The 25 MW is typical of the smaller 

plants discharging to POTWs and listed in the ERCO survey 

sample (18). Eighty-seven and one half percent of all 

plants listed and discharging to POTWs have less than 100 MW 

IGC, with 37.5 percent having less than 25 IGC. Seventy-six 

percent of the generating capacity discharging to POTWs is 

in the size range between 250 and 1000 MW, and the 500 MW 

plant is considered representative of this large size group. 

For the 25 MW model plant it was assumed that pretreatment 

would be a batch operation with low volume and metal 

cleaning wastes combined. Treatment would consist of 

gravity separation (skimming) of oils, followed by lime 

precipitation of metals, sedimentation, withdrawal of 

sludge, adjustment of pH to a neutral range, and controlled 

discharge. Figure VIII-1 is a flow diagram for a small 

batch plant. For the 500 MW it was assumed that pretreatment 

would be on a semicontinuous basis. Metal cleaning wastes 

would be stored in an equalization tank and bled into the 

treatment operation at a controlled rate. The treatment 

process would consist of oil and grease skimming in the 

equalization tank, lime addition in the reactor, sedimentation 

and clarification, and final adjustment of pH before 

discharge to the public sewer. Sludge from the clarifier 

would be dewatered on vacuum filters, with the filtrate 

returned to the treatment plant influent. Figure VIII-2 is a 

flow diagram of this process. 

These model treatment plants provide a level of treatment 

consistent with effluent guide1 ines for direct discharge. 

For metal cleaning wastes, the removals of metals are 

limited to the minimum solubilities discussed in Section 

VI I. 

Blowdown from the cooling water system is a significant 

waste stream not included in the combined pretreatment 

plants. Level D pretreatment for discharge to the POTW 

consists of dechlorination and pH adjustment. A flow 

diagram for accomplishing this pretreatment is shown on 

Figure VIII-3. 

Cost Variances 

Age 

Age affects the cost of pretreatment in terms of cost per 

unit of power produced primarily because age affects 

efficiency and p1 ants with lower efffi ci ency wi 11 produce 

more wastes per unit of power produced. Plants with lower 

efficiency will also have lower utilization and therefore 

produce fewer units of power in relation to their installed 

capacity. 
LOW VOLUME WASTES 

200 gpd/MW 

METAL CLEANING WASTES 

4 gpd/MW 

BOILER BLOWDOWN 

40 gpd/MW 

LIME ACID 

FIGURE VIII-1. Model Waste Pretreatment Plant 25 MW Generating Faci 1 ity For Level D Pretreatment 
DRAFT 

CLEANING WASTES (5.4 gpd/MW) 

BOILER TUBE 

BOILER FIRESIDE 

AIR PREHEATER 

OIL & GREASE 

5.4 gpd/MW 

EQUALIZATION 

TANK - 

raw VOLUME WASTES (320 gpdh~) 

WATER TREATMENT? LIME 

AIR POLLUTION CONTROL-. 

FLOOR DRAINS- 

'LABORATORY'& SAMPLING. - 

ACID 

CLARIFIER 

I' 

SLUDGE 

4r FILTER SEWER 6 TO POTW 

FIGURE VIII-2. Model Waste Pretreatment Plant 500 MW 

Generating Facility for Level D Pretreatment 

VIII-18 
DRAFT 

Size 

Size is related to age in that the older plants are more 

likely to be smaller than the newer plants. This relation 

is shown in detail in the Development Document (14). 

Size affects the cost of pretreatment as shown by the 

two plant sizes, 25 MW and 500 MW. 

Location 

Location affects costs of pretreatment because of 

differences in construction costs and labor rates in 

various parts of the U.S. and because the choice of the 

treatment technology and the cost of providing that 

technology are related to the availability of land. For 

plants discharging to public sewers, it may be assumed 

that they are located in urbanized areas, where land 

availability is somewhat limited. The extent of that 

limitation will vary widely depending on the size of 

the urban area, the location of the plant in that area, 

and the location of the area within the U.S. Cost 

estimates are presented for two cases, (1) where tankage 

can be constructed at ground level, and (2) where 

tankage must be supported on a steel framework over 

existing facilities because no other land is available. 

COST ESTIMATES 

Low Volume and Metal Cleaning Wastes 

Low volume wastes include all wastewaters other than those 

for which specific effluent limitations have been established. 

Waste sources include wet air pollution control systems, 

water treatment systems, laboratory and sampling streams, 

f 1 oor drainage, cool i ng tower basin cleaning , and bl owdown 

from service water systems. For the purpose of cost 

estimating, metal cleaning wastes have been combined with 

low volume wastes as the most cost effective method of 

handling these two waste sources. Pretreatment cost 

allottment to each type of waste has been estimated and is 

given in Table VIII-7. 
DRAFT 

Level - of Treatment 

Level D treatment consists of retention, skimming, 

pH adjustment for precipitation and readjustment before 

discharge and removal of sludges. Level D treatment 

meets the requirements of BPCTCA for direct discharge. 

Capi ta1 Costs 

The following table presents estimates for capital costs 

of pretreatment plants for Level D treatment of low 

volume and metal cleaning wastes, where sufficient land 

is available to construct all facilities at ground level. 

TABLE VIII-7 

ESTIMATED CAPITAL COSTS 

Zg 

CHEMICAL WASTES PRETREATMENT PLANT 

capacity .. .. Description - 25 MW 500 MW 

~qualization ~ank 

Reactor 

Clarifier 

Vacuum Filter 

Pumps 

Piping 

Subtotal, major equipment 

Installation & foundations 

Instrumentation 

Subtotal, construction costs 

Engineering & contingencies 

Total, land not limited $97,000 $612,000 

Premiumfor limited land construction 28,000 180,000 

Cost, per KW IGC $ 3.78 $ 1.12 

Limited land premium 1.12 0.36 

Estimated Cost Allottment, Unlimited and 

Low Volume Wastes 2.58 0.92 

Metal Cleaning Wastes 1.20 0.20 
DRAFT 

If land availability is limited, treatment plant components 

may have to be stacked vertically and tankage supported 

on steel framework. This would double the cost of the 

installation of the equipment. It would increase the 

total capital cost of the pretreatment plant for the 

25 MW generating facility, to $5.00 per KW KGC. For the 

500 MW facility, the respective costs would be $792,000 

and $1.58 per KW IGC. 

Operating Costs 

Operating costs include labor; fuel, power and other 

utilities; supplies (principally chemicals); maintenance; 

removal and disposal of residues; and management. 

Assumed unit costs for basic parameters of operating costs 

are shown in the following table. 

Table VIII-8. ASSUMED UNIT COSTS 

Labor, per hour, 

including fringe benefits 

Electricity, per kwh 

No. 2 Fuel oi 1, per MM Btu 

Chemicals 

Lime, per ton 

Sulfuric Acid, per ton 

The following table shows operating costs for the combined 

pretreatment of low volume and metal cleaning wastes in 

treatment plants of the type described in this report. 

Annual costs are calculated on the basis that the generating 

facility is operated as a base load plant operating 8000 

hours per year with each boiler cleaned once per year. 
DRAFT 

TABLE VIII-9 

OPERATING COSTS-PRETREATMENT OF 

LOW VOLUFE AND METAL CLEANING WASTES 

Operating Labor (1 ) 

Maintenance (2) 

Utilities 

Water (3 

Electric Power (4 

Sewer Charge (5) 

Chemicals and 

Supplies (6 

Total 

Ann'ual production, KWH 

Unit cost, mils per KWH 

At .90 capacity factor 

Installed Generating Capacity 

25 MW(7) 500 MW(8) 

-- -- 

Notes to Table VIII-9 

(1) 25 MW Plant - 4 hrs/wk 200 hrs/yr 

500 MW Plant - 40 hrs/wk 2000 hrs/yr 

(2) 3% of capital cost 

(3) City water @ .6O/lOO gall 

(4) 25 MW Plant - 5 kwh x 200 hrs 

500 MW Plant - 30 kwh x 2000 hrs 

(5) Sewer service charge @ .30/1000 gal 

(6) Lime 500 mg/l 

Sulfuric Acid 100 mg/l 

(7) Design flow: Low volume wastes: 5,000 gpd (from DD) 

Metal cleaning wastes : 25,000 gallons batch 

(8) Design flow: Low volume wastes 200,000 gpd (from DD) 

Metal cleaning wastes : 500,000 gal lons batch 
DRAFT 

Ash Transport Water 

Ash transport water is the water used in the hydraulic 

transport of bottom or fly ash. Since the water serves 

only as a carrier of the ash, water quality is not a 

significant consideration. As a matter of fact, a high 

level of suspended solids is desirable since it facilitates 

the subsequent settling out and removal of the ash. 

Settling basins are a normal component of ash transport 

systems. They may be either of the mechanical clarifier 

or natural lagoon (ash pond) type. Wet ash is removed 

from the clarifiers and disposed off site. The supernatent 

water is recycled to the process. The only routine blowdown 

from the system is the water removed with the wet ash. 

Waste streams result from overflows during periods of 

precipitation and for intermittant blowdown purposes. 

At one of the plants visited, blowdown from a recirculating 

water system used to transport fly ash from oil fueled 

boilers was discharged to the POTW. This waste can be 

combined with area runoff and could be treated together. 

Costs for pretreatment of discharges from ash transport 

systems are estimated from the volume of the portion 

coming to the retention pond. 

Metal Cleaning Wastes 

Metal cleaning wastes include wastes from the cleaning of 

the inside (waterside) of the boiler tubes, usually done 

by chemical means, and the outside (fireside) of the 

boiler and air preheater surfaces, usually done by 

mechanical means. Cleaning is done about once per year 

for each generating unit during a period when the unit 

is not in generating service. The wastes are discharged 

during a few hours over a two-day period and contain high 

concentrations of suspended solids, chemicals used in the 

cleaning process, and metal and other residues removed 

from the surfaces being cleaned. 
DRAFT 

Level of Treatment 

Level D treatment consists of retention, skimming, pH 

adjustment to specific levels to precipitate various metals, 

removal of sludges, and readjustment of pH for discharge. 

Costs 

The combined model treatment plants for low volume wastes 

have been sized to handle metal cleaning wastes as well. 

Costs for pretreatment of metal cleaning wastes are 

therefore included in the cost of pretreatment for low 

vol umes. 

Boi 7er Blowdown 

The quality of boiler blowdown is generally higher than 

the quality of the raw water source, which for most plants 

discharging to POTWs is the municipal water supply. If 

boiler blowdown is discharged to the waste stream, it will 

tend to dilute the wastes and make any treatment less 

efficient. Boiler blowdown should therefore be returned 

to the plant service water system, and In most plants 

this is done. Therefore, no costs have been developed for 

pretreatment of this waste source. 

Cooling System Wastes 

Cooling system wastes are discharges of water that have 

been used to cool the main condenser surfaces. Cooling 

systems are either of the once-through or recirculating 

type. There are no known plants which discharge 

once-through cooling water to a POTW. Recirculating 

systems require blowdown which becomes a waste source. 

Levels - of Treatment 

Levels A thru C treatment for cooling system blowdown 

consists of discharge to the POTW without pretreatment, If 

the only biocide or other cooling water treatment chemical 

used is chlorine and the POTW does not impose restrictions 

on chlorine in discharges to the sewer, cooling water 

blowdown may be discharged without pretreatment. In that 
DRAFT 

case the only costs will consist of the sewer service charges. 

Level D treatment for residual chlorine consists of 

dechlorination and possible pH adjustment and meets the 

requirements of effluent limitation guidelines for BPT for 

direct discharge. Level D treatment for cooling water 

system blowdown is shown in Figure VIII-3. 

Capital Costs 

Table VIII-10 presents estimates for capital costs of 

pretreatment for cooling water system blowdown. These costs 

assume that chlorine is used as a biocide, that the POTW 

requires removal of residual chlorine, and that no other 

biocides or inhibitors unacceptable to the POTW are added to 

the, cooling water system. 

Opesrating Costs 

Operating costs for pretreatment of cooling system blowdown 

pretreatment consists of operating labor, maintenance, and 

chemicals for dechlorination. They are summarized in 

Table VIII-11. 

Area Runoff 

The area runoff subcategory includes runoff from material 

storage. 

Coal is stored in open piles and oil is stored in covered 

tanks. Materials storage therefore represents a significant 

source of waste only for coal-fired plants. And since 

the burning of oil produces only about two percent of the 

amount of ash produced by the burning of coal, ash ponds 

are a feature of coal burning plants primarily. Material 

storage wastes from coal piles and ash ponds are therefore 

appl icable to coal burning plants only. 

No plants discharging area runoff to POTWs were found in 

the industry survey. 
DRAFT 

TURBINE 

iL1 COOLING 

1 

TOWER 

- - 

MAKE-UP 

I 

BLOWDOWN (I000 

- gpd/MW L 

CONDENSER 

I 

IME 

t - - I MONITOR I I - 

RESIDUAL I . CHLiiINE - 

FIGURE VIII-3. Cooling Water System Blowdown Treatment 

For Level D Pretreatment 
DRAFT 

Tab1 e ,VIII-10 

ESTIMATED CAPITAL COST 

COOLING WATER SYSTEM BLOWDOWN TREATMENT 

Installed Generating Capacity 

nescription 25 MW 500 MW 

Contact Tank 

Chemical Feed System 

Piping 

Subtotal, major equipment 

Installation & foundations 

Instrumentation 

Subtotal, construction costs 

Engineering O contingencies 

Total Cost 

Cost per KW IGC 

Tab1 e VIII-11 

ESTIMATED OPERATIKG COSTS 

COOLING WATER SYSTEM BLOWDOWN TREATMENT 

Installed Generating Capacity 

Description - 25 MW 500 MW 

Operating Labor 

Maintenance 

Chemicals 

Total 

Unit costs, mils/KWH 

at .90 capacity factor 
DRAFT 

Level D treatment for coal pile runoff and ash pond 

overflows consists of neutralization and sedimentation. 

Its cost is a function of the size of the catchment area 

covered by the coal pile and the ash pond and the design 

meteorological conditions at the particular site. The 

regulation (40 CFR 423.40) require that treatment 

facilities be sized to treat the runoff from a 10-year, 

24-hour rainfall event to produce an effluent having 

suspended solids of less than 50 mg/l and a pH between 

6.0 and 9.0. The applicable technology consists of 

lined ponds capable of holding various volumes of runoff. 

Capital Costs 

For a 500 MW plant, a coal pile representing 90 days 

storage will occupy 10 - 40 acres. A tetention basin 

designed to provide one hour detention at the maximum 

10 minute rate associated with a 10-year, 24 hour storm 

will generally meet the effluent requirement. Depending 

on location, such a retention basin could cost $27,000, 

$96,000, exclusive of land, or $0.05-$0.19 per KW IGC. 

Operatig Costs 

Operating costs for pretreatment facilities for runoff 

from coal piles and ash ponds are limited to chemicals 

for neutralizing. It is estimated that chemicals for 

this purpose would cost $360 per year for a 25 MW plant 

and $7,200 per year for a 500 MW plant. This corresponds 

to a unit cost of .0018 mils per KWH generated for a 

90 percent capacity factor. 

The following table (VIII-12) presents estimates for capital 

costs of pretreatment plants for Level C treatment of low 

volume and metal cleaning wastes for a coal-fired plant 

where sufficient land is not available. 

ULTIMATE DISPOSAL 

Costs -- For Land Destined Solid Wastes 

Waste treatment processes discussed in this report are 

separation techniques which produce a liquid fraction 

suitable for discharge to the public sewer or reuse 

within the plant and a liquid or solid residue which 

requires ultimate disposal. Many of the processes 

produce sludges containing between 0.5 and 5.0 percent 

solids. These sludges are generally further dewatered 

at the site to 15 to 30 percent solids and then disposed 

off site. The following paragraphs discuss techniques 

and costs of dewatering and ultimate disposal applicable 

to steam electric power plants. 
DRAFT 

Table VIII-12. ESTIMATED CAPITAL COSTS CHEMICAL 

WASTES PRETREATMENT PLANT LEVEL C 

Installed Generating Capacity 

Description 25 MW 500 MW 

Equalization Tank 

Reactor 

Clarifier 

Pumps 

pi ping 2,000 

Subtotal. ma.ior eaui~ment $ 33.000 

Instal lation-& ~ohdations ' 17 ;OOO 

Instrumentation 4,000 

Subtotal, construction 

costs $ 54,000 

Enginnering & Contingenci es 16,000 

Total, land not limited $ 70,000 $ 270,000 

Premium for limited land 

construction 20,000 80,000 

Cost per KW IGC 

Limited Land Premium 

Estimated cost allottment, unlimited land 

Low volume wastes 2.40 

Metal cleaning wastes 1.20 
DRAFT 

User Charges For Sewer Service 

Of the twenty-two plants visited in this study only 

15 percent reported separate charges for sewer service, 

while 35 percent reported surcharges on their water bills 

for sewer service. Fifty percent did not report charge 

for sewer service as they were municipal utilities whose 

internal billing systems did not allow for tracking of 

such charges. 

The average charge for sewer service in this industry is 

$0.06/1000 L ($0.23/1000 gal ). 

Evaporation Ponds 

Evaporation ponds are used by the industry as a method of 

ultimate disposal, particularly in the arid areas of the 

southwestern United States. The extensive land requirements 

make it unsuited for use in urban areas where plants 

discharging to POTWs are generally located. 

Conveyance Off Site 

The cost of this method of disposal is entirely related to 

the distance between plant and disposal site. Alternate 

methods of conveyance are trucks, railroads and pipelines. 

Trucking is most economical for distances under 50 miles. 

Costs are of the order of ($.01-$0.13 per 1000 liter) 

($0.05-$0.50 per 1,000 gallon) miles exclusive of final 

disposal charges. 

Landfills 

Landfills are the most common method of disposal of 

solid wastes. Costs of disposal at landfills range from 

$1 to $9 per metric ton ($2-10 per ton). Recent federal 

regulations require landfills to provide leachate control, 

so that soluble components of the wastes cannot cause 

groundwater pollution. 
DRAFT 

ENERGY CONSIDERATIONS 

In contrast to the effluent guidelines for thermal 

discharges, the promulgation of standards for pretreatment 

is not expected to involve significant energy requirements 

or to have a measurable impact on the energy production 

of the power plant. None of the treatment technologies 

described herein affect the power generating cycle and 

therefore do not require "retrofitting" to the extent 

that the performance of the plant is impaired. None of 

the processes involve a change of state and the only 

requirements for energy are for possible pumping needs. 

Even these needs are site dependent and many power plants 

may find it feasible to install the equipment in such a 

manner that repumping is not required. 

For estimating purposes it has been assumed that a 

pretreatment plant handling low volume and metal cleaning 

wastes from a 25 MW generating plant would have a connected 

load of 5HP and that a similar plant for the 500 MW 

generating facility would have a connected load of 30 HP. 

Each plant would operate the equivalent of 800 hours per 

year, at full connected load. Under these conditions, the 

energy consumption by the waste treatment facilities would 

constitute about 0.02 percent of the generating capacity 

of the 25 MW generating plant and less than 0.01 percent 

of the generating capacity of the 500 MW plant. 
DRAFT 

SECTION IX 

PRETREAMENT STANDARDS 

"To be Propo,sed by the Environmental Protection Agency" 
DRAFT 

SECTION X 

ACKNOWLEDGMENTS 

The preparation of this report was accomplished through the 

efforts of the staff of the Environmental Engineering 

Department, Hittman Associates, Inc., Columbia, Maryland 

under the overall direction of Mr. Burton C. Becker, Vice 

President, Operations. Mr. Dwight B. Emerson and Mr. 

J. Carl Uhrmacher shared direction of the day-to-day work 

on the program. 

Mr. John Lum, Project Officer, Effluent Guidelines Division, 

through his assistance, leadership, and advice has made an 

invaluable contribution to the preparation of this report. 

Mr. Lum provided a careful review of the draft report and 

suggested organizational, technical and editorial changes. 

He also was most helpful in making arrangements for the 

drafting, presenting, and distribution of this report. 

Mr. Ernest P. Hall, Jr., Assistant Director, Effluent 

Guidelines Division and Mr. Harold B. Coughlin, Branch 

Chief, Effluent Guidelines Division, Mr. Devereaux Barnes, 

and Mr. Elwood Forsht, Project Officers, Effluent Guidelines 

Division offered many helpful suggestions during the 

program. 

Appreciation is extended to the Federal Power Commission, 

Washington D.C., and to Mr. Vacys Saulis, Region V 

Office of the Environmental Protection Agency, Chicago, 

Illinois, to acknowledgment James Ferry-EPAIOffice of 

Planning and Evaluation Garry F. Otakie-EPAIOffice of Water 

programs, Theordore Landry-EPA Region I, Fred Roberts 

EPA Corvallis, Oregon Environmental Research Laboratory, 

Harvey Lunenfeld-EPA Region 11, Gary Liberson-EPA Office 

of Analysis and Evaluation for assistance and cooperation 

rendered to us in this program. Additionally, we wish to 

thank Mr. John Rose of Daniel P. Frankfurt, PC, for his 

invaluable aid. 

Also our appreciation is extended to the staff of the 

Environmental Engineering Department of Hittman Associates, 

Inc. for their assistance during this program. Specifically, 

our thanks to: 

Dr. Leon C. Parker, Senior Chemical Engineer 

Dr. T. Goldshmid, Environmental Engineer 

Mr. J. Carl Uhrmacher, Senior Chemical Engineer 

Mr. Roger S. Wetzel, Environmental Engineer 
DRAFT 

Ms. 

Mr. 

Mr. 

Mr. 

Mr. 

Mr. 

Mr. 

Mr. 

Mr. 

Barbara A. White, Manuscript Coordinator 

Craig S. Koralek, Environmental Engineer 

Kenneth G. Budden, Environmental Engineer 

Robert G. Matysek, Junior Chemical Engineer 

Carroll E. Stewart, Chemical Engineer 

Robert T. Brennan, Environmental Engineer 

Efim M. Livshits, Environmental Engineer 

Anthony T. Shemonski, Environmental Engineer 

Werner H. Zieger, Environmental Engineer 
DRAFT 

SECTION XI 

REFERENCES 

Barker, P.A., "Water Treatment for Steam Generating 

Systems", Industrial Water Engineering, MarchIApril 

1975. 

City Council of Roswell, New Mexico, Ordinance No. 933, 

Industrial Waste Ordinance -- of The City - of Roswell, 

New Mexi co. 

Dean, John G., Bosqui, Frank L., and Lanouette, 

Kenneth H., "Removing Heavy Metals from Wastewater," 

Environmental Science and Technology, Volume 6, 

No. 6, June 1972. 

Duffey, J.G.,Gale, S.B., and Bruckenstein S., 

"Electrochemical Removal of Chromates and Other 

Metals," Cooling Towers, Volume 2, pp. 44-50, 1975. 

Goldstein, Paul, "Control of Chemical Discharges for 

the Steam Electric Power Industry1; NUS Corporation, 

Pitssburg, PA., Presented at Conference on Water 

Quality - Considerations for Steam Electric Power 

Plants, Atomic Industrial Forum, Inc., Phoenix, AZ, 

January 1975. 

Nall, Douglas E., "The Influence of EPA Guidelines 

on Treatment of Power Plant Wastes," Industrial 

Water Engineering. 

Office of Science and Technology, Electric Power 

-- and the Environment, August 1970. 

Patterson, J.W., et al, Wastewater Treatment Technology, 

Illinois Institute for Environmental Qua1 ity, Chicago, 

Illinois, August, 1971. 

Scott, David L., Pollution in the Power Industry, 

D.C. Heath and Co., Lexington,MA, 1973. 

Stratton, Charles L., and Lee, G. Fred, "Cooling 

Towers and Water Quality," Journal of the Water 

Pollution Control Federation, Volume 47, No. 7, 

July 1975. 

Teknekron, Inc., Water Pollution Control of the 

Steam Electric Power Industry - Assessment of the 

Costs and Capabilities of Water Pollution Control 

Technology -- for the SteamElectric Power Industry, 

Volume 1, Berkley, CAY December 1975. 
DRAFT 

Teknekron, Inc., Water Pollution Control -- of the 

Steam Electric Power Industry - Economic Impact 

Water Pollution Control -- in the Steam Electric 

Power Industry, Volume 2, Berkeley, CA, December, 

1975. 

Teknekron, Inc., Water Pollution Control -- for the 

Steam Electric Power Industry - Appendix, Volume 3, 

Berkeley, CA, December 1975. 

U.S. Environmental Protection Agency, Development 

Document for Proposed Effluent Limitations Guidelines 

-- and New Source Performance Standards -- for the Steam 

Electric Power Generating Industry, October, 1974. 

U.S. Environmental Protection Agency, Office of 

Water Program Operations, pretreatment of Pollution 

Introduced into Publically Owned ~reatrnent Works 

October 1973. 

U.S. Environmental Protection Agency, Office of 

Water Program Operations, State and Local Pretreatment 

Programs (Draft Federal Guidelines) Volume 1, August, 

1975. 

U.S. Federal Power Commission, Statistics of 

Publicly Owned Electric Utilities in the United 

States 1970, Washington, D.C., FebEaT1972. 

U.S. Environmental Protection Agency, Office of 

Planning and Evaluation, Environmental Assessment 

- of Alternative Thermal Control Strategies -- for the 

Electric Power Industry, December 1974. 

Fair, G.M., Geyer, C.G., and Okun, D.A., Water 

and Wastewater Engineering, New York, NY, 1968. 
DRAFT 

SECTION XI1 

GLOSSARY 

Absolute Pressure. The total force per unit area measured 

above absolute vacuum as a reference. Standard atmospheric 

pressure is 101,326 N/l12 (14.696 psi) above absolute vacuum 

(zero pressure absoluter. 

Absolute Temperature. The temperature measured from a 

zero at which all molecular activity ceases. The volume 

of an ideal gas is directly proportional to its absolute 

temperature. It is measured in OK (OR) corresponding to 

"C + 273 (OF + 459). 

Anion. The charged particle in a solution of an electrolyte 

which carries negative charge. 

Anthracite. A hard natural coal of high luster which 

contains little volatile matter. 

Approach Temperature. The difference between the exit 

temperature of water from a cooling tower, and the wet 

bulb temperature of the air. 

Ash. The solid residue following combustion of a fuel. 

Ash Sluice. The transport of solid residue ash by water 

flow in a conduit. 

Backwash. Operation of a granular fixed bed in reverse 

flow to wash out sediment and reclassify the granular 

rnedi a. 

Bag Filters. A fabric type filter in which dust laden 

gas is made to pass through woven fabric to remove the 

particulate matter. 

Base. A compund which dissolves in water to yield 

hydroxyl ions (OH-). 

--- Base-Load Unit. An electric generating facility operating 

continously at a constant output with little hourly or 

daily fluctuation. 
DRAFT 

Biocide. An agent used to control biological growth. 

Bituminous. A coal of intermediate hardness containing 

between 50 and 92 percent carbon. 

Blowdown. A portion of water in a closed system which 

is wasted in order to prevent a built-up of dissolved 

solids. 

Boiler. A device in which a liquid is converted into its 

vapor state by the action of heat. In the steam electric 

generating industry, the equipment which converts water 

into steam. 

Boiler Feedwater. The water supplied to a boiler to be 

converted into steam. 

Boiler Fireside. The surface of boiler heat exchange 

elements exposed to the hot combustion products. 

Boiler Scale. An incrustation of salts deposited on the 

waterside of a boiler as a result of the evaporation of 

water. 

Boiler Tubes. Tubes contained in a boiler through which 

water passes during its conversion into steam. 

Bottom Ash. The solid residue left from the combustion 

of a fuel, which falls to the bottom of the combustion 

chamber. 

Brackish Water. Water having a dissolved solids content 

between that of fresh water and that of sea water, 

generally from 1000 to 10,000 mg per liter. 

Brine. Water saturated with a salt. 

-- Bus Bar. A conductor forming a common junction between two 

or more electric circuits. A term commonly used in the 

electric uti 1 i ty industry refer to electric power leaving 

a station boundary. Bus bar costs would refer to the cost 

per unit of electrical energy leaving the station. 
DRAFT 

Capacity Factor. The ratio of energy actually produced 

to that which would have been produced in the same period 

had the unit been operated continously rated capacity. 

Cation. The charged particles in solution of an electrolyte 

which are positively charged. 

Carbonate Hardness. Hardness of water caused by the 

presence of carbonates and bicarbonates of calcium and 

magnesium. 

Circulating Water Pumps. Pumps which deliver cooling 

water to the condensers of a power plant. 

Circulating Water System. A system which conveys cooling 

water from its source to the main condensers and then to 

the point of discharge. SYnonymous with cooling water 

system. 

Clarification. A process for the removal of suspended 

matter from a water solution. 

Clarifier. A basin in which water flows at a low velocity 

to allow settling suspended matter. 

Closed Circulating Water System. A system which passes 

water through the condensers, then through an articial 

cooling device, and keeps recycling it. - 

-- Coal Pile Drainage. Runoff from the coal pile as a result 

of rainfall. 

Condensate Polisher. An ion exchanger used to adsorb 

minute quantities of cations and anions resent in 

condensate as a result of corrosion and erosion of metallic 

surfaces. 

Condenser. A device for converting a vapor into its liquid 

phase. 

Construction. Any placement, assembly, or installation of 

facilities or equipment (including contractural obligations 

to purchase such facilities or equipment) at the premises 

where the equipment will be used, including preparation 

work at the premises. 
DRAFT 

Convection. The heat transfer mechanism arising from the 

motion of a fluid. 

Cooling Canal. A canal in which warm water enters at one 

end, is cooled by contact with air, and is discharged at 

te other end. 

Cooling Lake. See Cooling Pond. 

Cooling Pond. A body of water in which warm water is cooled 

by contact with air, and is either discharged or returned 

for reuse. 

Cooling Tower. A configured heat exchange device which 

transfers reject heat from circulating water to the 

atmosphere. 

Cooling Tower Basin. A basin located at the bottom of a 

cooling tower for collecting the falling water. 

Cooling Water System. See Circulating Water System. 

Corrosion Ihibitor. A chemical agent which slows down 

or prohibits a corrosion reaction. 

Counterflow. A process in which two media flow through 

a system in opposite directions. 

Critical Point. The temperature and pressure conditions at 

which the saturated-liquid and saturated-vapor states of 

a fluid are identical. For water-steam these conditions 

are 3208.2 psia and 705.47"F. 

Cycling Plant. A generating facility which operates 

between peak load and base load conditions. In this 

report, a facility operating between 2000 and 6000 hours 

per year. 

Cyclone Furnace. A water-cooled horizontal cylinder in 

which fuel is fired, heat is released at extremely high 

rates, and combustion is completed. The hot gases are 

then ejected into the main furnace. The fuel and 

combustion air enter tangentially, imparting a whirling 

motion to the burning fuel, hence the name Cyclone Furnace. 

Molten slag forms on the cyclinder walls, and flows off 

for removal. 
DRAFT 

Deaeration. A process by which dissolved air and oxygen 

are stripped from water either by physical or chemical 

methods. 

Deaerator. A device for the removal of oxygen, carbon 

dioxide and other gases from water. 

Degasification. The removal of a gas from a liquid. 

Deionizer. A process for treating water by removal of 

cations and anions. 

Demineralizer. See Deionizer. 

Demister. A device for trapping liquid entrainment from 

gas or vapor streams. 

Dewater. To remove a portion of the water from a sludge 

or a slurry. 

Dew Point. The temperature of a gas-vapor mixture at 

which the vapor condenses when it is cooled at constant 

humidity. 

Diesel. An internal combustion engine in which the 

temperature at the end of the compression is such that 

combustion is initiated without external ignition. 

Discharge. To release or vent. 

Discharge Pipe or Conduit. A section of pipe or conduit 

from the condenser discharge to the point of discharge 

into receiving waters or cooling device. 

Drift. Entrained water carried from a cooling device by 

the exhaust air. 

Dry Bottom-Furnace. Refers to a furnace in which the ash 

is collected as a dry solid in hoppers at the bottom of 

the furnace, and removed from the furnace in this state. 

Dry Tower. A cooling tower in which the fluid to be 

cooled Tlows within a closed system. This type of tower 

usually uses finned or extended surfaces. 

Dry Well. A dry compartment of a pump structure at or 

be1 ow pumping level , where pumps are 1 ocated. 
DRAFT 

Economizer. A heat exchanger which uses the heat of 

combustion gases to raise the boiler feedwater 

temperature before the feedwater enters the boiler. 

Electrostatic Precipitator. A device for removing particles 

from a stream of qas based on the principle that these 

particles carry eiectrostatic charges and can therefore 

be attracted to an electrode by imposing a potential across 

the stream of gas. 

Evaporation. The process by which a liquid becomes a 

vapor. 

Evaporator. A device which converts a liquid into a vapor 

by the addition of heat. 

Feedwater Heater. Heat exchangers in which boiler 

feedwater is preheated by steam extracted from the 

turbine. 

Filter Bed. A device for removing suspened solids from 

water, consisting of granular material placed in 

horizontal layers and capable of being cleaned 

hydraulically by reversing the direction of the flow. 

Filtration. The process of passing a liquid through a 

filtering medium for the removal of suspned or colloidal 

matter. 

Fireside Cleaning. Cleaning of the outside surface of 

boiler tubes and combustion chamber refractories to 

remove deposits formed during the combustion. 

-- Flue Gas. The gaseous products resulting from the 

combustion process after passage through the boiler. 

Fly Ash. A portion of the non-combustible residue from 

a furwhich is carried out of the boiler by the flue gas. 

Fossil Fuel. A natural solid, liquid or gaseous fuel such 

as coal, petroleum or natural gas. 

Generation. The conversion of chemical or mechanical 

energy into electrical energy. 

-- Heat Rate. The fuel heat input (in Joules or BTU) 

required to generate a KWH. 
DRAFT 

Heating Value. The heat available from the combustion of 

a given quantity of fuel as determined by a standard 

calorimetric process. 

Humidity. Pounds of water vapor carried by 1 1b of dry air. 

Ion. A charged atom, molecule or radical, the migration 

of which affects the transport of electricity through an 

electrolyte. 

Ion Exchange. A chemical process invol vi ng reversible 

interchange of ions between a liquid and a solid but no 

radical change in the structure of the solid. 

Lignite. A carbonaceous fuel ranked between peat and coal. 

Makeup Water Pumps. Pumps which provide water to replace 

that lost by evaporation, seepage, and blowdown. 

Mechanical Draft Tower. A cooling tower in which the air 

flow throuqh the tower is maintained b.y fans. In forced 

draft towers the air is forced throughVthe tower by fans 

located at its base, whereas in induced draft towers the 

air is pulled through the tower by fans mounted on top of 

the tower. 

Mill. One thousandth of a dollar. 

Mine-mouth Plant. A steam electric powerplant located 

within a short distance of a coal mine and to which the 

coal is transported from the mine by a conveyor system, 

slorry pipe1 ine or truck. 

Mole. The molecular weight of substance expressed in grams 

(orpounds). 

Name Plate. See Nominal Capacity. 

Natural Draft Cooling Tower. A cooling tower through 

which air is circulated by natural or chimney effect. 

A hyperbolic tower is a natural draft tower that is 

hyperbol i c in shape. 

Neutralization. Reaction of acid or alkaline solutions with 

the opposite reagent until the concentrations of hydrogen 

and hydroxyl ions are about equal. 
DRAFT 

New Source. Any source, the construction of which is 

commenced after the publicated of proposed Section 306 

regulations. 

Nominal Capacity. Name plate - design rating of a plant, 

or specific piece of equipment. 

Nuclear Energy. The energy derived from the fission of 

nuclei of heavy elements such as uranium or thorium or 

from the fusion of the nuclei of light elements such as 

deuterium or tritium. 

Once-through Circulating Water System. A circulating 

water system which draws water from a natural source, 

passes it through the main condensers and returns it to 

a natural body of water. 

Overflow. (1) Excess water over the normal operating 

limits disposed of by letting it flow out through a device 

provided for that purpose; (2) The device itself that 

allows excess water to flow out. 

Osmosis. The process of diffusion of a solvent thru a 

semi-permeable membrane from a solution of lower to one 

of higher concentration. 

Osmotic Pressure. The equilibrium pressure differential 

across a semi-permeable membrane which separates a solution 

of lower from one or higher concentration. 

Oxidation. The addition of oxygen to a chemical compund, 

generally, any reaction which involves the loss of 

electrons from an atom. 

Packing (Cooling Towers). A media providing large surface 

area for the purpose of enhancing mass transfer, usually 

between a gas or vapor, and a liquid. 

Precipitation. A pheonomenon that occurs when a substance 

held in solution in a liquid phase passes out of solution 

into a solid phase. 

Preheater (Air). A unit used to heat the air needed for 

combustion by absorbing heat from the products of 

combustion. 
DRAFT 

-- Peak-load Plant. A generating facility operated only 

during periods of maximum demand, in this report is is a 

facility operating less than 2000 hours per year. 

Penalty. A sum to be forfeited, or a loss due to some 

action. 

Plant Code Number. A four-digit number assigned to all 

powerplants in the industry inventory for the purpose 

of this study. 

Plume (Gas). A conspicuous trail of gas or vapor emitted 

from a cooling tower or chimney. 

Powerplant. Equipment that produces electrical energy, 

generally by conversion from heat energy produced by 

chemical or nuclear reaction. 

Psychrometric. Refers to air-water vapor mixtures and their 

properties. A psychrometric charg graphically displays 

the relationship between these properties. 

Pulverized Coal. Coal that has been ground to a powder, 

usually of a size where 80 percent passes through a 

#ZOO U.S.S. sieve. 

Pump Runout. The tendency of a centrifugal pump to 

deliver more than its design flow when the system 

resistance falls below the design head. 

Pyrites. Combinations of iron and sulfur found in coal as 

FeS2. - 

Radwaste. Radioactive waste streams from nuclear powerplants. 

Range. Difference between entrance and exit temperature 

of water in a cooling tower. 

Rankine Cycle. THe thermodynamic cycle which is the basis 

of the steam-electric generating process. 

--- Rank of Coal. A classification of coal based upon the 

fixed carbon on a dry weight basis and the heat value. 

Recirculation System. Facilities which are specifically 

designed to divert the major portion of the cooling water 

discharge back to the cooling water intake. 
DRAFT 

Recirculation. Return of cooling water discharge back to 

the cooling water intake. 

Regeneration. Displacement from ion exchange resins of the 

ions removed from the process solution. 

Reheater. A heat exchange device for adding superheat to 

steam which has been partially expanded in the turbine. 

Relative Humidity. Ratio of the partial pressure of the 

water vapor to the vapor pressure of water at air 

temperature. 

Reinjection. To return a flow or portion of flow, into a 

process. 

Reverse Osmosis. The process of diffusion of a solvent 

thru a semi-perable membrane from a solution of higher to 

one or lower concentration, affected by raising the pressure 

of a more concentrated solution to above the osmotic 

pressure. 

Reduction. A chemical reaction which involes the addition 

of electrons to an ion to decrease its positive valence. 

Saline Water. Water containing salts. 

Sampling Stations. Locations where several flow samples 

are tapped for analysis. 

Sanitary Wastewater. Wastewater discharged from sanitary 

conveniences of dwellings and industrial facilities. 

Saturated - Air. Air in which the water vapor is in 

equilibrium with the liquid water at air temperature. 

Saturated Steam. Steam at the temperature and pressure at 

which the liquid and vapor phase can exist in equilibrium. 

Scale. Generally insoluble deposits on heat transfer 

surfaces which inhibit the passage of heat through these 

surfaces. 

Scrubber. A device for removing particles and/or objectionable gases from a stream of gas. 

Secondary Treatment. The treatment of sanitary wastes 

water by biological means after primary treatment by 

sedimentation. 
DRAFT 

Sedimentation. The process of subsidence and deposition 

of suspended matter carried by a liquid. 

Sequestering Agents. Chemical compunds which are added 

to water systems to prevent the formation of scale by 

holding the insoluble compunds in suspension. 

Service Water Pumps. Pumps providing water for auxiliary 

plant heat exchangers and other uses. 

Slag Tap Furnace. Furnace in which temperature is high 

enough to maintain ash (slag) in a molten state until it 

leaves the furnace through a-tap at the bottom. The 

slag falls into the sluicing water whwere it cools, 

disintegrates, and is carried away. 

Slimicide. An agent used to destroy or control slimes. 

Sludge. Accumulated solids separated from a liquid during 

processing. 

Softener. Any device used to remove hardness from water. 

Hardness in water is due mainly to calcium and magnesium 

salts. Natural zeolites, ion exchange resins, and 

precipitation processes are used to remove the calcium 

and magnesium. 

Spinning Reserve. The power generating reserve connected 

to the bus bar and ready to take load. Normally consists 

of units operating at less than full load. Gas turbines, 

even though not running, are considered spinning reserve 

due to their quick start up time. 

Spray Module (Powered Spray Module). A water cooling 

device consisting of a pump and spary nozzle or nozzles 

mounted on floats and moored in the body of water to be 

cooled. Heat is transfered principally by evaporation 

from the water drops as they fall through the air. 

Station. A plant comprising one or several units for the 

generation of power. 

Steam Drum. Vessel in which the saturated steam is 

separated from the steam-water mixture and into which the 

feedwater is introduced. 
DRAFT 

Supercritical. Refers to boilers designed to operate at 

or above the critical point of water 22,100 knIm2 - and 

374.0°C (3206.2 psia and 705.4"F). 

Superheated Steam. Steam which has been heated to a 

temperature above that corresponding to saturation at 

a specific pressure. 

Thermal Efficiency. The efficiency of the thermodynamic 

cycle producing work from heat. The ration of usable 

energy to heat input expressed as percent. 

Thickening. Process of increasing the solids content of 

sludge. 

Total Dynamic -- Heat (TDH). Total energy provided by a 

pump consisting of the difference in elevation between 

the suction and dischage levels, plus losses due to 

unrecovered velocity heads and friction. 

Turbidity. Presence of suspended matter such as organic 

or inorganic material plantkton or other microscopic 

organisms which reduce the c l a r i t y o f the water. 

Turbine. A device used to convert the energy of steam 

or gas into rotation mechanical energy and used as prime 

mover to drive electric generation. 

Unit. In steam electric generation, the basic system for 

power generation consiting of a boiler and its associated 

turbine and generator with the required auxiliary equipment. 

Utilitx. Public utility. A company, either investorowned or publicly owned which provides service to the 

public in general. The electric utilities generate and 

distribute electric power. 

Volatile Combustion Matter. The relatively light components 

in a fuel which readily vaporize at a relatively low 

temperature and which when combined or reacted with 

oxygen, give out light and heat. 

Wet Bottom Furnace. See slag-tap furnace. 

-- Wet Bulb Temperature. The steady-state, nonequilibrium 

temperature reached by a small mass of water immersed under 

adiabatic conditions in a continous stream of air. 
DRAFT 

Wet Scrubber. A device for the collection of particulate 

matter from a gas stream and/or absorption of noxious 

gases from the stream. 

Zeolite. Complex sodium aluminum silicate materials, 

which have ion exchange properties and were the 

original ion exchange materials before synthetic 

resins were processed. 
DRAFT 

APPENDIX A 

STATISTICAL ANALYSIS OF HISTORICAL DATA 

Effluent pretreatment standards achievable by steam electric 

power plants discharging their wastewater effluents into 

publicly-owned treatment facilities were determined from 

statistical analysis of historical data describing the 

pollutants concentration over extended periods of time. Of 

the three plants analyzed only one provides partial 

pretreatment which includes flow equal ization, oi 1 removal, 

and settling. The remaining two plants discharge untreated 

waste. This appendix describes the statistical approach 

used and presents results of that analysis. 

The statistical analysis was based on the assumption that 

the data are normally distributed, that is, their frequency 

of occurrence is fully defined by two statistical parameters: 

The mean X and the standard deviation s. Each set of data 

representing the variation of concentration of a particular 

pollutant in treated effluent-was statistically examined to 

determine the mode of normal distribution that best describes 

its frequency of occurrence. Both arithmetic and logarithmic 

modes of normal distribution were considered. The degree of 

fit of the data to any particular mode was determined by 

calculating the coefficients of skewness and of kurtosis. 

The former measures the symmetry of the distribution diagram 

and the latter measures the height of the peak of the 

diagram relative to that of a normal curve. A perfect fit 

to normal distribution is indicated by a zero coefficient 

of skewness and a coefficient of kurtosis of three. 

If neither the arithmetic nor the logarithmic modes of 

normal distribution describe the frequency of occurrence of 

a data set, a modified logarithmic mode was employed to 

"force" the data into normal distribution. This mode is 

referred to as the three-parameters logarithmic type of 

normal distribution. It is assumed that deviation from 

normal distribution occurs in the tails of the frequency 

curve where the probability of occurrence is very low. 

Thus, it is assumed that deviation of data from the perfect 

logarithmic mode of normal distribution is due to small 

sample size. The overall effect of this deviation is to 

increase the variance of the data set. The three-parameters 

approach is designed to remove this deviation in the tails 

by adding or subtracting a constant number, smaller than 

the first element of the data set, to each member of the 

sample. The exact value of the constant is determined by 
DRAFT 

iterating a series of mathematical expressions designed 

to generate a zero coefficient of skewness and a value 

of approximately three for the coefficient of kurtosis. 

The mathematical treatment of data was carried out by a 

computer program. Each set of data was initially read by 

the computer which sorted elements in ascending order. 

The computer then calculated the first four moments and 

the coefficients of skewness and kurtosis for each of the 

three modes of normal distribution. The statistical 

coefficients of the three-parameters logarithmic mode of 

normal distribution were determined by initially assigning 

an arbitrary constant to be added to each element of the 

data set. The computer calculated the coefficient of 

skewness and determined from its value whether the 

diviation from normal distribution occurred at the lower 

or upper tail of the diagram. A deviation in the lower 

tail was indicated by a negative value and the computer 

proceeded to correct it by adding to each of the elements 

half of the arbitary constant. A positive coefficient of 

skewness was corrected by subtracting half of the constant. 

This was repeated until a zero coefficient of skewness 

was obtained. The computer then calculated the percent 

cumulative of each element in the series and converted it 

to standard deviation expressed as probit (standard 

deviation plus five). 

Based on the values of the coefficients of skewness and 

kurtosis the mode of normal distribution that best described 

the distribution of the data set was selected and the data 

were subjected to a least squares analysis as a function 

of the corresponding probits to determine the coefficients 

of regression (slope, intercept, and coefficient of 

determination). The regression line was used to determine 

the 99 percent confidence upper limits. 

Table 1 lists the mathematical expressions used to calculate 

the various statistical parameters. These are shown in 

Tables 2 to 6 for various pollutants discharged from three 

pants. Each of these tables shows the calculated values of 

the first four moments, and the coefficients of skewness and 

kurtosis, for each of the modes of normal distribution. Also 

shown in these tables are the constants used to normalize 

the distribution of the data, the coefficients of regression 

(slope, intercept, and coefficient of determination), and 

the 99 percent confidence limits. Plots of the best fit 

data and their regression lines are shown in Figures 1 to 19. 

The statistical parameters of the best fit data are summarized 

in Table 7. The historical data analyzed are listed in 

Table 8. 
DRAFT 

Table A-1. MATHEMATICAL EXPRESSIONS FOR DETERMINATION 

OF STATISTICAL PARAMETERS 

n 

First moment rn =- I C xi (mean) 1 n 

i =l 

Second moment m=- X: - x2 (variance) 2 n 

i=l 

Third moment 

n n n 

Fourth moment m4= x x:? n " x;+"* n z - 3x4 

i =l i=1 i =l 

Coefficient of skewness Y = % m2 

Coefficient of kurtosis & = m4 

2 

m2 

Probi t 
DRAFT 

Slope 

Intercept 

Coefficient of determination 

Xi - the value of element i of a data set. Xi=X' for arithmetic mode, 

Xi=log Xi for logarithmic mode, and Xj=log !xi + a) for threeparameters mode of normal distribution, where a is the added or 

subtracted constant. 

n - number of elements in a data set 

Co - 2.515517 dl - 1.432788 

C1 - 0.802853 d2 - 0.189269 

C2 - 0.010328 dg - 0.001308 

E(Q)< 4.5 x 10+ 
Table A-2: STATISTICAL ANALYSIS OF HISTORICAL DATA (MG'/L) 

Plant No. 7308 Wastewater Source: Retention Pond 

Pollutant I Iron I Nickel I Si 1 ver 

Mode of Normal 

Distribution 

Statistical 

Parameter I I Arithmetic 

Third Moinent I 0.28 1 0.00 1 --- 1 0.035") 

Mean 

Variance 

Logarithmic Logarithmic 

Three 

Parameters 

Logarithmic 

4.75 

0.68 

Arfthnletic Arithmetic 

, I I I I I I 

Correction Constant 1 I I 1 I -0.92 I I 

Logarithmic 

4.86 

0.005 

Fourth Moment 

Coeff. of Skewness 

Coeff. of Kurtosis 

2.40 

51214.64' 

I I I I I I I 

1.73 

0.09 (1) 

I 

Slope I I I I I I 

(1) calculated with data x 100 

--- 

1.45 ' 

3.18 ( 

0.77 

0.49 

1.63 

Intercept 

Coeff. of Determination 

99% Confidence Limit 

0.00 

0.4 

1.51 

1.88 1.15(') 1 1.58(1) 1 

-4.67 1 1 

0.91 

6.67 

0.002(l) 

-1.15(') 

2.33(') 

I 1 

I 

0.97(') 

3.1 

6.64 (1) 

-1.15 ( 1 1 

(1) 2.33 

0.026 (1) 

1.21 (1 

2.87 (1 

-4.17(') 1 -3.52(1) I 

I 

0.33 (' ) 

0.07 

0.78(:) 

0.00~~) 

2.16(') 
Table A-3. STATISTlCAL ANALYSIS OF HISTORICAL DATA (MG/L) 

Plant No. 7308 Wastewater Source: Cooling Tower Basin 

1 I 

Pollutant Iron I Copper 1 Chromium 

Ari thmetic 

- - 

Logarl thmic 

Three 

Parameters 

Logarithmic 

Kode of Normal 

Parameter 

Three 

Parameters 

togarithmic 

Arl thmetic 

Logari thmic 

Ari thmetic 

Logarl thmic 

Mean 

Variance 

Third Moment 

Fourth Moment 

Coeff. of Skewness 

Coeff. of Kurtosis 

Correction Constant 

Slope 

Intercept 

Coeff. of Determi nation 

99% Confidence Limit 

(I) calculated with data x 100 
Table A-3. STATISTICAL ANALYSIS OF HISTORICAL DATA (MG/L) (CONTI..NUED) 

Lead 

Parameter 

Variance 543.1 

Fsurth Noment 1 712419.5 1 

I I 

Coeff. of Skewness 1 0.'87 1 

I 

Coeff. of Kurtosis 2.41 

'1 correction constant ( I 

Slope 

Intercept 1 I 

Corff. of Determination 

I 

99% Confidence Limit I 1 

LogaI thmic 

I Zinc 

Three 

Parameters 

Loga- Arith- Logari thmic 

Three 

Parameters 

Loga- Arithri thiilic metic 

Three 

Parameters 

Loga- Logari thrnic ri thmic 

(1) pH units 

(2) cat culated with data x 100 

(3) calculated with data x. 10 
Table A-4. STATISTICAL ANALYSIS OF HISTORICAL DATA (MG/L) 

Plant No. 8696 Wastewater Source: Demineral izer 

t Pollutant 

, 

Suspended Sol ids BOD COD 

I I 

Three 

Parameters 

Logari thmic 

Three 

Parameters 

Art thMode of Normal 

Ofstrlbutlon 

Statistica Ari thParameter metlc 

Three 

Parameters 

Loga- Arithrithmic 

Arl thmetic 

Logart thmlc 

Fourth Moment 319.44 

Coeff. of Skewness 0. 50 

Coeff. of Kurtosis 1.60 

Correction Constant 

Slooe 

Intercept L 

Coeff. of Determination 

99I Confidence Lfmtt 

(1) @i units 
Table A-5. STATISTICAL ANALYSIS OF HISTORICAL DATA (MGIL) 

t 

Plant No. 8696 Wastewater Source: Cooling tower blowdown 

Pollutant Suspended Sol Ids COD 

Three 

Parameters 

Statistical Arith- Loga- Ari th- Loga- Loga- Ari thParameter metic rithmic metic ri thmic rithmic metic 

Mean 7.46 0.87 14.25 13.48 13.59 2.54 

Variance 0.08 0.0003 18.35 0.01 7 0.013 0.84 

I Third Moment I 0.01 I 0.00 1 48.30 1 -0.00018 1 0.00 1 -0.04 

I Fourth Moment 1 0.007 1 0.00 1 926.85 1 0.00079 1 0.0005 1 1.2 

1 Coeff. of Skewness 1 0.6 1 0.47 1 0.61 1 -0.083 1 0.00 1 -0.05 -- -- 

Coeff. of Kurtosis 1.13 9.42 2.75 2.72 2.65 1.683 

Correction Constant I 1.54 

I slope 1 0.33 1 I I 1 0.13 1 -- 

Intercept 5.83 0.50 

Coeff. of Determination 0.92 0.96 

99% Confidence Limit 8.11 15.39 h 

ri thmic 

Three 

Parameters 

Logari thmi 

(1) pH units 
Table A-6. STATISTICAL ANALYSIS OF HISTORICAL DATA (MG/L) 

Plant No. 8392 Wastewater Source: Cooltng tower Bot ler 

Pollutant 

Distribution 

Statistical 

Parameter 

Mean 

Variance 

Third Moment 

Fourth Moment 

Coeff. of Skewness 

Coeff. of Kurtosis 

Correction Constant 

Slope 

Intercept 

Coeff. of Oetermi na tion 

99% Confidence Limlt 

m 

Chromate 

I Three 

Parameters 

Arithnetic Logarl thmtc Logarithnlc 

P 

Phosphate 

Three 

Parameters 

Artthmetfc Logarithmic Logarithmic 

17.1 16.59 16.51 

13.98 0.009 0.002 
Table A-7. STATISTICAL PARAMETERS SUMMARY FOR BEST FIT DATA (MG/L) 

I Coolfng Tower Blowdown I Demi neral i zer 

Source (Plant 8696) (Plant 8696) 1' 

I I 99% 

Statistical Concentration Confidence Statfstlcal Concentratlon 

Parameter Mode I Limit I Mode 1 Mean Limi t I 

PH 

Suspended Solids 

Source I 

Logarlthmfc 

3-Parameter 

Cooling Tower Blowdown 

(Plant 8392) 

b 

Ari thmetf c 

3-Parameter 

Boiler 

(Plant 8392) 

2.36 

26.40 

Cooling Tower Basin 

(Plant 7308) 

7.46 

13.59 

3.85 

27.55 

Parameter 

Chromate 

Phosphate 

I 

8.11 

15.39 

Source 

3-parameter 

3-parameter 

Arithmetic 

I 

Parameter 

Fe 

C u 

-- - 

Retention Pond 

4.26 9.26 

8.55 97.56 

2.53 

Statlstical 

Mode 

Arf thmetlc 

3-parameter 

6.89 

3-parameter 1 22.27 

16.51 

3-parameter 

Parameter 

F e 

N i 

28.20 

17.78 

14.53 16.24 

Concentration 

Mean 

5.27 

0.58 

I Ag Arithmetic 

3-parameter . 

99% 

Confidence 

Limit 

12.83 

0.80 

Ari thmetfc 

3-parameter -- -p 

.O. 04 0.03 I 

4.75 

1.3 

6.67 

3.1 
DRAFT 

Table A-8. HISTORICAL DATA LMG/L) --- 

Plant No. 8696 

Cooling Tower Blowdown 

COO 24.0, 29.0, 27.0, 12.0, 33.0, 30.0, 30.0, 31.0, 

2.2, 24.0, 23.0, 21.0, 20.0 

Dernineralizer Backwash 

COD 22.0, 19.0, 21,0, 7.0, 13.0, 22.0, 22.0, 24.0.. 

39.0, 39.0, 13.0, 71.0, 57.0, 18.0, 20.0, 83.0, 

Plant No. 8392 

Cooling TFwx 

chromate 16,0, 24.0, 18.0, 14.0, 16.0, 14.0, 14.0, '4.'- 14.0* 

12.0, 10.0, 14.0, 14.0. 16.0, 14.0, 14.0. 16.0, 16.0* 

14.0 

Boiler 

Phosphate 15.0, 18.0, 16.0, 26.0, 19.0, 15.0, 18.0, 13.0, 20.0, 

17.0, 14.0, 12.0, 10.0, 20.0, 13.0, 21.0, 19.0, 18.0 

Plant No. 7308 

Retention Pond 

Fe 4.0, 179.0, 4.0, 6.0, 5.0 

Cooling Tower Basin 

F e 11.4, 7.25, 5.75, 1.0, 7.5, 3.5, 4.5, 1.3 

C u 0.05, 1.35, 0.12, 0.1, 0.1 
DRAFT 

3.0 4.0 5.0 6.0 7.0 

PROBITS 

FIGURE .A-1. Normal Distribution Diagram for Supsended Sol ids 

Concentration in Wastewaters from Demineralizer 

(Plant 8696) 
5.0 6.0 

PROBITS 

F1GURE.A-2. Normal Distribution Diagram for Phosphates Concentration 

In Boiler Blowdown (Plant 8696) 
3.0 4.0 5.0 6.0 7.0 

PROBITS 

FIGURE A-3. Normal Distribution Diagram for pH Concentration 

In Wastewater from Deminealizer (Plant 8696) 
DRAFT 

3.0 4.0 5.0 6.0- 

PROBITS 

FIGURE A-4.Normal Distribution Diagram for COD Concentration 

In Wastewater From Dernineralizer(P1ant 8696) 
5.0 

PROBITS 

FIGURE A--5. Normal Distribution Diagram for Supsended Sol ids Concentration 

In Cooling Tower Blowdown (Plant 8696) 
5.0 6.0 

PROBITS 

FIGURE A-6. Normal Distribution Diagram for COD Concentration In 

Coolinq Tower Blowdown (Plant 86961 
PROBITS 

GURE A-7. Normal Distribution Diagram for Chrornates Concentration 

Cooiing Tower Blowdown (Plant 8395) - 
5.0 6.0 7.0 

PROBITS 

FIGURE A-8. Normal Distribution Diagram for BOD5 Concentration In Cooling 

Tower Blowdown (Plant 8696) 
PROBITS 

FIGURE A-9.. Norma? Distribution Diagram for pH Concentration In 

Cooling Tower Blowdown (Plant 8696) 
DRAFT 

3.0 4.0 ' 5.0 6.0 7.0 

PROBITS 

FIGURE A-1 il., Normal Distribution Diagram for BOD5 

Concentration in Demineralizer Backwash 

(Plant 8696) 
DRAFT 

4 .O 5.0 6.7 7.0 

PROBITS 

FIGURE A-11.. Normal Distribution Diagram for Normalized Nickel 

Concentration in Retention Pond (Plant No. 7308) 
DRAFT 

4.0 5.0 6.0 

PROBITS 

FIGURE .A-1 2. Normal Distribution Diagram for Normal ized 

,Chrom'ium Concentration in Cool ing Tower Basin 

(Plant No. 7308) 
DRAFT 

4.0 5.0 6.0 7.0 

PROBITS 

FIGURE- A-1 3. Normal Distribution Diagram for Normal ized 

Lead Concentration in Cooling Tower Basin (Plant No. 7308) 
DRAFT 

I I 

4 .O 5.0 6.Q 

PROBITS 

FIGURE A-14. Normal Distribution Diagram for Normalized 

Z1.n~ Concentration In Cooling Tower Basin (Plant No. 7308) 
DRAFT 

4 .O 5 .O 6 .O 

PROBITS 

FIGURE A-15. Normal Distribution Diagram for Iron 

Concentration in Retenti~n Pond (Plant No. 7308) 
PROBITS 

FIGURE A-16. N'ormal Distribution Diagram for Iron Concentration 

In Cooling Tower Basin (Plant No. 7308) 
5.0 6.0 

PROBITS 

FIGURE A-17. Normal Distribution Diagram for Normalized pH Concentration 

In Cooling Tower Basin (Plant No. 7308) 
DRAFT 

4.0 5.0 6.0 

PROBITS 

FIGURE A-18. Normal Distribution Diagram for Silver 

Concentration Retention Pond (Plant No. 7308) 
DRAFT 

PROBITS 

FIGURE A-19. Normal Distribution ~ia~ram for Normalized 

copper Concentration Cooling Tower Basin (Plant No.7308) 
DRAFT 

APPENDIX B 

WATER GLOSSARY 
DRAFT 

WATER GLOSSARY 

Acid-washed activated carbon - Carbon which has been contacted with an acid solution with the purpose of 

dissolving ash in the activated carbon. 

Acidity - The quantitative capacity of aqueous solutions 

to react with hydroxyl ions. It is measured by 

titration with a standard solution of a base to a 

specified end point. Usually expressed as miligrams 

per liter of calcium carbonate. 

Acre-foot - (1) A term used in measuring the volume of 

water that is equal to the quantity.of water required 

to cover 1 acre 1 ft deep, or 43,560 cu ft. (2) A 

term used in sewage treatment in measuring the volume 

of material in a trickling filter. One acre-foot 

contains 43,560 cu ft of water. 

Activated Carbon - Carbon which is treated by high-temperature heating with steam or carbon dioxide producing 

an internal porous particle structure. The internal surface area of granular activated carbon is 

estimated to be about 3,600 sq ft gr. 

Activiated Sludge Treatment Process - (See Sludge, Activated). 

Adsorption - The adhesion of an extremely thin layer of 

molecules (of gas, liquid) to the surfaces of solids 

(granular activiated carbons for instance) or liquids 

with which they are in contact. 

Adsorption isotherms (activated carbon) - A measurement of 

adsorption determined at a constant temperature by 

varying the amount of carbon used or the concentration 

impurity in contact with the carbon. 

Advanced Waste Treatment - Any treatment method or process 

employed fol lowing biological treatment (1 ) to increase 

the removal of pollution load. (2) to remove substances 

that may be deleterious to receiving waters or the 

environment. (3) to produce a high-quality effluent 

suitable for reuse in any specific manner or for discharge under critical conditions. The term tertiary 

treatment is commonly used to denote advanced waste 

treatment methods. 
DRAFT 

Aerated Pond - A natural or artificial wastewater treatment 

pond in which mechanical or diffused air aeration is 

used to supplement the oxygen supply. 

Aeration - The bringing about of intimate contact between 

air and liquid by one of the following methods spraying the liquid in the air, bubbling air through the liquid 

(diffused aeration) agitation of the liquid to promote 

surface absorption of air (mechanical aeration). 

Aerobic - Living or active only in the presence of oxygen. 

Aerobic Biological Oxidation - Any waste treatment or process utilizing aerobic organisms in the presence of 

air or oxygen, as the agent for reducing pollution load 

or oxygen demand or organic substances in waste. The 

term is used in reference to secondary treatment of 

wastes. 

A1 icide - Chemicals used in the control of phytoplankton + algae) in bodies of water. 

Alkalinity - The capacity of water to neutralize acids, a 

property imparted by the water's content of carbonates, 

bicarbonates, hydroxides, and occassional ly borates , silicates, and phosphates. It is expressed in miligrams per liter of equivalent calcium carbonate. 

Anaerobic - Living or active only in the absence of free 

oxygen. 

Anaerobic Biological Treatment - Any treatment method or 

process utilizing anaerobic or facultative organisms 

in the absence of air for the purpose of reducing 

the organic matter in wastes or organic solids settled 

out of wastes commonly referred to as anaerobic digestion or sludge digestion when applied to the treatment 

of sludge solids. 

Anaerobic Waste Treatment - Waste stabilization brought about through the action of microorganisms in the absence 

of air or elemental oxygen. Usually refers to waste 

treatment by methane fermentation. 
DRAFT 

Anion Exchange Process - The reversible exchange of negative ions between functional groups of the ion exchange 

medium and the solution in which the solid is immersed. 

Used as a wastewater treatment process for removal of 

anions, e.g., carbonate. 

Anionic Surfactant - An ionic type of surface-active substances that has been widely used in cleaning products. 

The hydrophilic group of these surfactants carries a 

negative charge in washing solution. 

Apparent Density (Activated Carbon) - The weight per unit 

volume of activated carbon. 

Appurtenances, Sewer - Structures, devices and appliances, 

other than pipe or conduit, which are integral parts 

of a sewerage'system: such as manholes flush tanks, 

surface inlets. 

Aquifer - A subsurface geological structure that contains 

water. 

Assimilative Capacity - The capacity of a natural body of 

water to receive: (a) wastewaters without deleterious 

effects: (b) toxic materials, without damage to 

aquatic life or humans who consume the water; (c) BOD 

within prescribed dissolved oxygen limits. 

Autooxidation - A chemical system which will oxidize automatically when some set of conditions are met such as 

temperature, oxygen supply, moisture content, etc. 

Backflow Prevention - A system designed to protect potable 

water from wastewater contamination which could occur 

if wastewater pressure exceeds potable water pressure 

over a cross-connection where one or more check valves 

fail. 

Backsiphonage - The flowing back of contaminated or polluted 

water from a plumbing fixture or cross connection into 

a water supply line,-due to a lowering of the pressure 

in such line. 

Backwashing - The process of cleaning a rapid sand or mechanical filter by reversing the flow of water. 
DRAFT 

Bacterial Examination - The examination of water and wastewater to determine the Dresence. number. and identification of bacteria. Also cal led-bacterial anaiysis. 

Baffles - Deflector vanes, guides, grids, gratings, or 

similar devices constructed or placed in flowing water 

or sewage to (1) check or effect a more uniform distribution of velocities; (2) absorb energy; (3) divert 

guide, or agitate the liquids; and (4) check eddy 

currents. 

Banks, Sludge - Accumulations on the bed of a waterway of 

deposits of solids of sewage or industrial waste 

origin. 

Bed Depth (Activated Carbon) - The amount of carbon expressed 

in length units which is parallel to the flow of the 

stream and through which the stream must pass. 

Bioassay - (1) An assay method using a change in biological 

activit.~ as a qualitative or quantitative means of 

analyzing a materials reponse'to industrial wastes and 

other wastewaters by using viable organisms or live 

fish as test organisms. 

Biochemical Oxygen Demand (BOD) - (1) The quantity of oxygen 

used in the biochemical oxidation of orqanic matter in 

a specified time, at a specified temperature, and under 

specified conditions (2) standard test used in assessing wastewater strength. 

Biocides - Chemical agents with the capacity to kill biological life forms. Bactericides, insecticides, pesticides, etc. are examples. 

Biodegradable - This part of organic matter which can be 

oxidized by bioprocesses, e.g., biodegradable detergents, food wastes, animal manure, etc. 

Biological Wastewater Treatment - Forms of wastewater treatment in which bacterial or biochemical action is intensified to stablize, oxidize, and nitrify the unstable 

organic matter present. Intermittent sand filters, contact beds, trick1 ing filters, and activated sludge 

process are exampl es. 
DRAFT 

Blowoff - A controlled outlet on a pipeline, tank, or 

conduit which is used to discharge water or accumulations of material carried by the water. 

Branch - (1) A special form of vitrified sewer tile and 

cast iron pipe used for making connections to a sewer 

or water main. They are called T, Y, T-Y, double Y, 

and V branches according to their respective shapes. 

(2) Any part of a piping system other than a main. 

Broad-Crested Weir - A weir having a substantial width of 

crest in the direction ~arallel to the direction of 

flow of water over it. This type of weir supports 

the nappe for an appreciable length and produces no 

bottom contraction of the nappe. Also called widecrested weir. 

Buffer - Any of certain combinations of chemicals used to 

stablize the pH values or alkalinities of solutions. 

Bulking Agent - A fine solid material which is sometimes 

added to a wastewater stream to promote clarification 

or coagulation by adding bulk to the solids. 

Bulking, Sludge - A phenomenon that occurs in activated 

sludge plants whereby the sludge occupies excessive 

volumes and will not concentrate readily. 

Cake, Sludge - The material resulting from air drying or 

dewatering sludge (usually forkable or spadable) . 

Calibration - The determination, checking, or rectifying 

of the graduation of any instrument giving quantitative 

measurements. 

Carbon Column A - A column filled with granular activated 

carbon whose primary function is the preferential adsorption of a. particular type or types of molecules. 

Carbon Tetrachloride Activity - The maximum percentage 

increase in weight of a bed of activated carbon after 

air saturated with carbon tetrachloride is passed 

through it at a given temperature. 

Catalyst - A substance which accelerates or retards a 

chemical reaction without undergoing any permanent 

changes. 
DRAFT 

Cation Exchange Process - The reversible exchange of positive 

ions between functional groups of the ion exchange medium 

and the solution in which the solid is immersed. Used 

as a wastewater treatment process for removal of cations, 

e.g. calcium. 

Cationic Surfactant - A surfactant in which the hydrophilic 

group is positively charged; usually a quaternary 

ammonium salt such as cetyl trimethyl ammonium bromide (CeTAB), C16H33N t (CH3)3 Br Cationic surfactant 

as a class are poor cleaners, but exhibit remarkable 

disinfectant properties. 

Cesspool - An underground pit into which raw household sewage 

or other untreated liquid waste is discharged and from 

which the liquid seeps into the surrounding soil or is 

otherwise removed. Sometimes called leaching cesspool. 

Chamber Detritus - A detention chamber larger than a grit 

chamber usually with provision for movinq sediment 

without interrupting the flow of liquid.- A settling 

tank of short detention period designed, primarily 

to remove heavy settleable solids. 

Chamber, Flowing-Through - The upper compartment of a twostory sedimentation tank. 

Chamber, Grit - A smal'l detention chamber or an enlargement 

of a sewer designed to reduce the velocity of flow of 

the liquid, to permit the separation of mineral from 

organic solids by differential sedimentation. 

Chelating Agents - A chelating agent can attach itself to 

central metallic atom so as to form a heterocyclic 

ring. Used to make ion-exchange more selective for 

specific metal ions such as nickel, copper, and cobalt. 

Chemical Analysis - The use of a standard chemical analytical procedures to determine the concentration of a 

specific pollutant in a wastewater sample. 

Chemical Coagulation - The destabilization and initial 

aggregation of colloidal and finely divided suspended 

matter by the addition of a floc-forming chemical. 
DRAFT 

Chemical Oxygen Demand (COD) - (1) A test based on the fact 

that all organic compounds, with few exceptions can be 

oxidized to carbon dioxide and water by the action of 

strong oxidizing agents under acid conditions. Organic 

matter is converted to carbon dioxide and water regardless of the biological assirnilabil ity of the substances. 

One of the chief limitations is its a b i l i t y t o d i f - 

ferentiate between biologically oxidizable and biologically inert organic matter. The major advantage of 

this test is the short time required for evaluation 

(2 hr). (2) The amount of oxygen required for the 

chemical oxidation of organics in a liquid. 

Chemical Precipitation - (1) Pre~ipita~tion iduced by addition of chemicals, (2) the process of softeninq water 

by the addition of lime and'soda ash as the precipitants. 

Chemisorption - Adsorption where the forces holding the 

adsorbate to the adsorbent are chemical (valance) 

instead of physical (van der Waals). 

Chlorination - The application of chlorine to water or wastewater, generally for the purpose of disinfection, but 

frequently for accompl ishingU other biological orchemical results. 

Chlorination break point - The application of chlorine to 

water, sewage, or industrial waste containing free 

ammonia to the point where free residual chlorine is 

available. 

Chlorination, Free Residual - The application of chlorine 

to water, sewage or industrial wastes to produce 

d i r e c t l y o r through the destruction of ammonia, or of 

certain organic nitrogenous compounds a free available 

chlorine residual. 

Chlorine, Available - A term used in rating chlorinated 

lime and hypochlorites as to their total oxidizing 

power. Also a term formerly applied to residual 

chlorine; now obsolete. 

Chlorine, Combined Available Residual - That portion of the 

total residual chlorine remaining in water, sewage or 

industrial wastes at the end of specified contact 

period, which will react chemically and biologically as 

chloramines or organic chloramines. 
DRAFT 

Chlorine Demand - The quantity of chlorine absorbed by 

wastewater (or water) in a given length of time. 

Chlorine, Total Residual - Free residual plus combined 

residual. 

Chlorite, High-test Hypo - A combination of lime and 

chlorine consisting largely of calcium hypochloride. 

Chlorite, Sodium Hypo - A water solution of sodium hydroxide 

and chlorine, in which sodium hypochlorite is the 

essential ingredient. 

Ci polletti Weir - A contract weir of trapezoidal shape, in 

which the sides of the notch are given a slope of one 

horizontal to four vertical to compensate as much as 

possible for the effect of end contractions. 

Clarifier - A sedimentation tank. 

Clear Well - A reservoir containing water which has been 

previously fi 1 tered or purified before goining into 

the standpipes or distribution system. 

Coils, digester - A system of pipes for hot water or steam 

installed in a sludge digestion tank for the purpose 

of heating the sludge being treated. 

Collection Systems - Piping and/or channel systems for 

gathering storm, domestic or industrial wastewaters. 

Can be combined or separate. 

Collector, Grit - A device placed in a grit chamber to 

convey deposited grit to one end of the chamber for 

removal . 

Collector, Sludge - A mechanical device for scraping the 

sludge on the bottom of a settling tank to a sump - pump, from which it can be drawn by hydrostat,ic or 

mechanical action. 

Colloids - A finely divided dispersion of one material 

called the "dispersed phase" (solid) in another 

material which is called the "dispersion medium" 

(liquid). Normally negatively charged. 
DRAFT 

Color - A measure of water quality, made by eye or with 

proper instrumentation. 

Color Bodies - Those complex molecules which impart color 

(usually undesirable) to a solution. 

Comminution - The process of cutting and screening solids 

contained in wastewater flow before it enters the flow 

pumps or other units in the treatment plant. 

Compatable Pollutant - A specific substance in a waste 

stream which alone can create a potential pollution 

problem, yet is used to the advantage of a'certain 

treatment process when combined with other waste 

streams. 

Complexing - The use of chelating or sequestering agents 

to form relatively loose chemical bonding as a means 

of treating certain pollutant such as nickel, copper, 

and cobalt. 

Composite Wastewater Sample - A combination of individual 

samples of water or wastewater taken at selected 

interval s, generally hourly for some specified period, 

to minimize the effect of the variability of the 

individual sample. Individual samples may have equal 

volume or may be roughly proportioned to the flow at 

time of sampling. 

Concentration, Hydrogen Ion - The weight of hydrogen ions 

in grams per liter of solution. Commonly expressed as 

the-p~ value that represents the logarithms of the 

receiprocal of the hydrogen ion concentration. 

Conductance - A measure of the conducting power of a solution 

equal to the reciprical of the resistance. The resistance is expressed in ohms. 

Contact Coagulation - A water clarification process which 

involves the addition of a coagulant with appropriate 

mixing for the purpose of floc formation within a 

filter media, which will be periodically back-flushed 

to permit the separation of the resulting solids from 

the main wastewater stream. 
DRAFT 

Contamination - A general term signifying the introduction 

into water of microorganisms, chemicals, wastes or 

sewage which renders the water unfit for its intended 

use. 

Contracted Weir - A V-notch or other shaped cross-section 

weir for the purpose of flow measurement, as opposed 

to a broad width weir for the purpose of level control. 

Contraction - (1) The extent to which the cross-sectional 

area of a jet, nappe, or stream is decreased after .. - 

passing an-orifice, weir, or notch. (2) The reduction 

in cross-sectional area of a conduit along its longitudinal axis. 

Control Section - The cross-section in a waterway which is 

the bottleneck for a siven flow and which determines 

the energy head required to produce the flow. 

Corporation Cock -A valve for joining a service pipe to a 

street water main; it is generally owned and operated 

by the water utility or department. It cannot be 

operated from the surface. 

Countercurrent Efficiency (Activated Carbon) - The unique 

advantage of a carbon column that permits spent antivated carbon to adsorb impurities before the semiprocessed stream comes in contact with fresh carbon. 

This allows the maximum capacity of the activated 

carbon to be utilized. 

Crest - The top of a dam, spillway, or weir, to which 

water must rise before passing over the structure. 

Critical Bed Depth (Activated Carbon) - In a carbon column 

the critical bed de~th is the de~th of aranular 

carbon which is partially spent.' It lies between the 

fresh carbon and the spent carbon and is the zone 

where adsorption takes place. In a single-column 

system this is the amount of carbon that is not completely utilized. 

Cross Connection - A water supply network and/or wastewater 

collection system which as been designed so as to prevent "cross-connections" which could result in functional damage to the system. The simpliest system is 

to have two separate systems, bu't this would not be 

justified if intersystems usage occurs only occasionally, 

hence back-flow preventers and other means are often 

used. 

B-ll 
DRAFT 

Cross-Sectional Bed Area (Activated Carbon) - The area of 

activated carbon throush which the stream flow is " 

perpendicular. 

Curb Cock - A shutoff valve attached to the water service 

pipe from the water basin to the building installed 

near the curb, which may be operated by means of a 

dye key to start or stop flow in the water supply 

lines of a building. 

Current Meter - A device for determining the velocity of 

moving water. 

Curve, Oxygen, Sag - A curve that represents the profile 

of dissolved oxygen connect along the course of a 

stream, resulting from deoxygenation associated with 

biochemical oxidation of organic matter and reoxygenation through the absorption of atmospheric 

oxygen and through biological photosynthesis. 

Data - Records of observations and measurements of physical 

facts, occurrences, and conditions, reduced to written, 

graphical, or tabular form. 

Data Correlation - The process of the conversion of reduced 

data into a functional relationship and the development of the significance of both the data and the 

relationships for the purpose of process evaluation. 

Data Reduction - The process for the conversion of raw 

field data into a systematic flow which assists in 

recognizing errors, omissions and the overall data 

qua1 i ty. 

Data Significance - The result of the statistical analysis 

of a data group or bank wherein the value or significance of the data receives a thorough appraisal. 

Dechlorination Process - A process by which excess chlorine 

is removed from water to a desired level, eq. 0.1 

mg/l maximum limit. Usually accomplished by chemical 

reduction, by passage through carbons beds or by 

aeration at a suitable pH. 

Degreasing - The process of removing greases and oils from 

sewage, waste, and sludge. 
DRAFT 

Demand, Biochemical Oxygen (BOD) - The quantity of oxygen 

utilized in the biochemical oxidation of organic 

matter in a specified time period and at a specified 

temperature. It is not related to the oxygen requirements in chemical combustion being determined entirely 

by the availability of the material as a biological 

food and the amount of oxygen by the microorganisms 

during the oxidation. 

Desorption - The opposite of adsorption. A phenomenon 

where an adsorbed molecule leaves the surface of the 

adsorbent. 

Detention Time - The time allowed for solids to collect in 

a settling tank. Theoretically detention time is equal 

to the volume of the tank divided by the flow rate. 

The actual detention time is determined by the purpose 

of the tank. Also, the design resident time in a 

tank or reaction vessel which allows a chemical reaction to go to completion, such as the reduction of 

chromium +6 or the destruction of cyanide. 

Dialysis - The separation of a colloid from a substance in 

true solution by allowing the solution to diffuse 

through a semi-permeable membrane. 

Diatomaceous Earth - A. filter medium used for filtration 

of effluents from secondary and tertiary treatments, 

particularly when a very high grade of water for 

reuse in certain industrial purposes is required 

also used as an adsorbent for oils and oily emulsions 

in some wastewater treatment designs. 

Differential Gauge - A pressure gauge used to measure the 

difference in pressure between two points in a pipe 

or receptacle containing a liquid. 

Diffuser - A porous plate or tube through which air is 

forced and divided into minute bubbles for diffusion 

in liquids. Commonly made of carborundum, alundurn 

and silica sand. 

Diffusion, Ridge and Furrow Air - A method of diffusing in 

an aeration tank of the activated sludge process, where 

porous tile diffusers are placed in depressions treated 

by the sawtooth construction of the tank bottom, in 

rows across the tank at right angles to the direction 

of flow. 
DRAFT 

Diffusion, Spiral Flow Air - A method of diffusing air in a 

aeration tank of the activated sludge process, where 

by means of properly designed baffles and the proper 

location of diffusers, a spiral helieal movement is 

given to both the air and the liquor in the tank. 

Digestion - The biochemical decomposition of organic matter 

which results in the formation of mineral and simpler 

organic compounds. 

Disinfection - (1) The k i l l i n g o f the larger portion (but 

not necessarily a1 1 ) of harmful and objectionable 

microorganisms in or on a medium by means of 

chemicals, heat, ultraviolet light, etc. (2) The use 

of a chemical additive or other treatment to reduce 

the number of bacteria particularly the pathogenic 

organisms. 

Dissolved Oxygen (DO) - The oxygen dissolved in sewage, 

water, or other 1 iquid, usually expressed in milisrams 

per liter or percent of saturation: It is the test 

used in BOD determination. 

Dissolved Solids - Theoretically the anhydrous residues of 

the dissolved constituents in water. Actually the 

term is defined by the method used in determination. 

In water and wastewater treatment the Standard Methods 

tests are used. 

Diurnal Flow Curve - A curve which depicts flow distribution 

over the 24 hour day. 

Drinking Water Standards - Standards defined by law and 

applied to the qua1 ity of drinking water. 

Educator (Activated Carbon) - A device with no moving parts 

used to force an activated carbon water slurry 

through pipes to the desired location. 

Effluent - (1) A liquid which flows out of a containing 

space (2) sewage, water or other liquid, partially 

or case may be, flowing out of a reservoir basin, or 

the use may be flowing out of a reservoir basin, or 

treatment plant or part thereof. 
DRAFT 

Electrical Conductivity - The reciprocal of the resistance 

in ohms measured between opposite faces of centimeter 

cube of an aqueous solution at a specified temperature. 

It is expressed as microohms per centimer at temperature degrees Celsius. 

Elutriation - A process of sludge conditioning in which 

certain constituents are moved by successive flushinq 

with fresh water or plant effluent thereby reducing - 

the need for using conditioning chemicals. 

Emergency Procedures - These various special procedures 

necessary to protect the environment from wastewater 

treatment plant failures due to power outages, chemical spills, equipment failures, major storms and floods, 

etc. 

Emulsion Breaking - The method of preventing the carryover 

of oils from one process to another by eliminating free 

oil by flotation,'and emulsions by the addition of 

aluminum or ferrous sulfate. 

End Contraction - (1) The extent of the reduction in the 

width of the nappe due to a constriction caused by 

the ends of the weir notch. (2) The walls of a weir 

notch which does not extend across the entire width 

of the channel of approach. 

Energy Head - The height of the hydraulic grade line above 

the center line of a conduit plus the velocity head of 

the mean velocity of the water in that section. 

Equalization Tank - A capacity used to equalize wastewater 

flows or pollutant concentrations in effluents thus 

distributing it more evenly by hours or days. 

Euetrophic'conditions - Lake water quality degradation by 

enrichment of nutrients resultinq in characteristics 

undersirable for means use of water. Plant growth 

in forms of microscopic algae and rooted aquatic 

weeds become prevelent in such situations. 

Fats (Wastes) - Triglyceride esters of fatty acids. 

Erroneously used as synonomous with grease. 
DRAFT 

Faculative - Having the power to live under different 

conditions either with or without oxygen. 

Feeder, Chemical, Dry- A mechanical device for applying 

dry chemicals to water sewage at a rate controlled 

manually or automatically by the rate of flow. 

Feeder Chemical Solution - A mechanical device for applying chemicals in liquid to water and sewage at a 

rate controlled manually or automatically by the 

rate of flow. 

Filter, High-Rate - A trickling filter operated at a high 

average daily dosing rate. All between 10 and 30 

mgd acre, sometimes including recirculation of 

effluent. 

Filter, Intermittent - A natural or artifical bed of sand 

or other fine-grained material to the surface of 

which sewage is intermittently added in flooding 

doses and through which it passes, opportunity being 

given for filtration and the maintenance of aerotic 

conditions. 

Filter, Low-Rate - A trickling filter designed to receive 

a small load of BOD Der unit volume of filterinci 

material and to have' a low dosage rate per unlt-of 

surface area (usually 1 to 4 mgdlacre). Also called 

standard rate filter. 

Filter, Rapid Sand - A filter for the purification of water 

where water which has been previously treated, usually 

by coagulation and sedimentation is passed downward 

through a filtering medium consisting of a layer of 

sand or prepared anthracite coal or other suitable 

material, usually from 24 to 30 in thick and resting 

on a supporting bed of gravel or a porous medium such 

as carborundum. The filrate is removed by an underdrain system. The filter is cleaned periodically by 

reversing the flow of the water upward through the 

filtering medium: sometimes supplemented by mechanical 

or air agitition during backwashing to remove mud and 

other impurities that are lodged in the sand. 
DRAFT 

Filter, Rouqhinq - A sewage filter of relatively coarse 

material operated at a high rate as a preliminary 

treatment. 

Filter, Trickling - A filter consisting of an artifical bed 

of coarse material, such as broken stone, clinkers, 

slats, or brush over which sewage is distributed and 

applied in drops, films, or spray, from troughs, 

drippers moving distributors or fixed nozzles and 

through which it trickles to the underdrain giving 

opportunity for the formation of zoogleal slimes 

which clarify and oxidize the sewage. 

Filter, Vacuum - A filter consisting of a cylindrical drum 

mounted on a horizontql axis, covered with a filter 

cloth revolving witha partial sumergence in liquid. 

A vacuum is maintained'under the cloth for the larger 

part of a revolution to extract moisture and the 

cake is scraped off continously. 

Filtration, Biological - The process of passing a liquid 

through a biological filter containing media on the 

surfaces of which zoogleal films develop which absorb 

and adsorb fine suspended colloridal and dissolved 

solids and which release various biochemical end 

products. 

float Gauge - A device for measuring the elevation of the 

surface of a liquid, the actuating element of which 

isWa buoyant float that rests on the surface of the 

liquid and rises or falls with it. The elevation of 

the surface is measured by a chain or tape attached 

to the float. 

- Floc - A very fine, fluffy mass formed by the aggre.gation 

of fine suspended particles. 

Flocculator - An apparatu.~ designed for the formation of 

f locTn water or sewage. 

Flocculation - In water and wastewater treatment, the 

agglomeration of colloidal and finely divided suspended matter after coagulation by gentle stirring 

by either mechanical or hydraulic means. In biological wastewater treatment where coagulation is not 

used, agglomeration may be accompl ished biologically. 
DRAFT 

Floatation - The rising of suspended matter to the surface 

of the liquid in a tank as scum by aeration, the 

evolution of gas, chemicals, electrolysis, heat, or 

bacterial decomposition and the subsequent removal 

of the scum by skimming. 

Flowrate - Usually expressed as liters/minute (gallons/ 

minute) or liters/day (million gallons/day). Design 

flowrate is that used to size the wastewater treatment 

process. Peak flowrate is 1.5 to 2.5 times design 

and relates to the hydraulic flow limit and is 

specified for each plant. Flowrates can be mixed 

as batch and continuous where these two treatment 

modes are used on the same plant. 

Flow-Nozzle Meter - A water meter of the differential 

medium type in which the flow through the primary 

el ement or nozzle produces a pressure difference- or 

differential head, which the secondary element, or 

float tube then uses as an indication of the rate of 

flow. 

Flow-Proportioned Sample - A sampled stream whose pollutants 

are attributed to contributing streams in proportion 

to the flow rates of the contributing streams. 

Frequency Distribution - An arrangement or distribution of 

quantities pertaining to a single element in order 

of their magnitude. 

Gauging Station - A location on a stream or conduit where 

measurements of discharse are customarily made. The 

location includes a stretch of channel through which 

the flow is uniform and a control downstream from 

this stretch. The station usually has a recording 

or other gauge for measuring the elevation of the 

water surface in the channel or conduit. 

Grab Sample - A single sample of wastewater taken at 

neither set time nor flow. 

Grease - In wastewater, a group of substances including fats, 

waxes, free fatty acids, calcium and magnesium soaps, 

mineral oils, and certain other nonfatty materials. 

The type of solvent and method used for extraction 

should be stated for quantification. 
DRAFT 

Grease Skimmer - A device for removing floating grease or 

scum from the surface of wastewater in a tank. 

- Grit - The heavy matter in water or sewage such as sand, 

gravel and cinders. 

Grit Chamber - A detention chamber or an enlargement of a 

sewer desiqned to reduce the velocity of flow of the 

liquid to permit the separation of m3neral from 

organic solids by differential sedimentation. 

Hardness - A characteristic of water, imparted by salts of 

calcium, maqnesium, and iron such as bicarbonates. 

carbonates ,-sulfates, chlorides, and nitrates that 

cause curdling of soap, deposition of scale in boilers, 

damage in some industrial process, and sometimes 

objectionable taste. It may be determined by a standard laboratory procedure or computed from the amounts 

of calcium and magnesium as well as iron, aluminum, 

manganese, barium, strontium, and zinc, and is 

expressed as equivalent calcium carbonate. 

Heat of Adsorption - The heat given off when molecules are 

adsorbed. 

Heavy Metals - A general name given to the ions of metallic 

elements such as copper, zinc, chromium, and aluminum. 

They are normally removed from a wastewater forming an 

insoluble precipitate (usually a metallic hydroxide). 

Hook Gauge - A pointed, U-shaped hook attached to a graduated staff or vernier scale, used in the accurate 

measurement of the elevation of a water surface. The 

hook is submerged, and then raised, usually by means 

of a screw, until the point just makes a pimple on 

the water surface. 

Hydraulic Surge - A pressure increase in a pipeline which 

accompanies a sudden decrease in the flow velocity. 

In some cases this increased pressure may cause 

rupture of the pipe. 

Industrial Wastes - The liquid wastes from industrial processes as distinct from domestic or sanitary wastes. 

Incineration - The combustion (by burning) of organic matter 

in wastewater sludge solids after water evaporation 

from the solids. 
DRAFT 

Index, Sludge - The volume ofmillillters occupied by aerate'd 

mixed liquor containing 1 gram of dry solids after 

settling 80 min. commonly referred to as the Mohlman 

index. The Donaldson index which is also commonly 

used is obtained by dividing 100 by the Mohlman index. 

Influent - Sewage, water or other liquid, either raw or 

partly treated, flowing into a reservoir basin, or 

treatment plant or any part thereof. 

Invert - The floor, bottom or lowest portion of the internal 

cross section of a closed conduit. 

Iodine Number (Activated Carbon) - The iodine number is the 

mi'lliliterof iodine adsorbed 1 gram of carbon at a 

filtrate concentration of 0.02~-iodine. 

Ionization - The process of the formation of ions by the 

splitting of molecules of electrolytes in solution. 

Irrigation Spray - Irrigation by means of nozzles along a 

pipe on the ground or from perforated overhead pipes. 

Lagoon - (1 ) A shallow body of water as a pond or lake', 

which usually has a shallow, restricted inlet from 

the sea. (2) A pond containing raw or partially treated 

wastewater in which aerobic or anaerobic stabilization 

occurs. 

Lime - Any of a family of chemicals consisting essentially 

of calcium hydroxide made from limestone (calcite) 

which is composed almost wholly of calcium carbonate 

or a mixture of calcium and,magnesium carbonates. 

Liquor, Mixed - A mixture of activated sludge and sewage in the aeration tank undergoing activated sludge 

treatment. 

Liquor, Supernatant - (1) The liquor overlying deposited 

solids. (2) the liquid in a sludge digestion tank 

which lies between the sludge at the bottom and the 

floating scum at the top. 

Loss of Head Gage - A gage on a rapid sand filter which 

indicates the loss of head involved in the filtering - 

operation whereby the operator is able to ascertain 

the need for filter backwashing. 
DRAFT 

Macropore - The pores in activated carbon which are larger 

(diameter) than 1.000A. 

Makeup Carbon - Fresh granular activated carbon which must 

be added to a column system after a regeneration cycle 

or when deemed necessary to bring the total amount of 

carbon to specification. 

Manometer - An instrument for measuring pressure. It 

usually consists of a U-shaped tube containing a 

liquid the surface of which is one end of the tube 

moves proportionally with changes in pressure on 

the liquid in the other end. Also, a tube type of 

differential pressure gauge. 

Mean Velocity - The average velocity of a stream flowing in 

a channel or conduit at a given cross section or in a 

given reach. It is equal to the discharge divided by 

the cross sectional area of the reach. Also called 

average velocity. 

Mesh Size (Activated Carbon).- The particle size of granular 

activated carbon as determined by the U.S. Sieve series. 

Particle size distribution within a mesh series is 

given in the specification of the particular carbon. 

Methylene Blue Number (Activated Carbon) - The methylene 

blue number is the milligrams of methylene blue 

adsorbed by 1 gram of carbon in equilibrium with a 

solution of methylene blue having a concentration 

of 1 .0 mg/l. 

Methylorange Alkalinity - A measure of the total alkalinity 

of an aqueous suspension or solution. It is measured 

by the quantity of sulfuric acid required to bring the 

water pH to a value of 4.3 as indicated by the change 

in color of methyl orange. It is expressed in miligrams CaC03' per 1 i ter. 

Micropore - The pores in activated carbon which range in 

size (diameter) from 10 to 1,000 A. 

Milligrams Per Liter (mg/l) - This is a weight per volume 

designation used in water and wastewater analysis. 

Mixed Media Filtration - A filter which uses 2 or more filter 

material s of differinq specific qravi ties selected so -. - 

as to produce a filter uniformly graded from coarse 

fine. 
DRAFT 

Monitoring - (1) The procedure or operation of locating 

and measuring radioactive contamination by means of 

survey instruments that can detect and measure, as 

dose rate, ionizing radiations. (2) The measurements 

sometimes continous, of water quality. 

Most Probable Number (MPN) - That number of organisms per 

unit volume that, in accordance with statistical 

theory, would be more likely than any other number 

t o y i e l d the obserbed test result with the greatest 

frequency. Expressed as the organisms per 

100 ml. Results are computed from the number of 

positive findings of coliform-group organisms resulring from mu1 tiple-portion decimal -dilution plantings. 

Nappe - The sheet or curtain of water overflowing a weir 

or dam. When freely overflowing any given structure, 

it has a well-defined upper and lower surface. 

Neutralization - Reaction of acid or alkali with the 

opposite reaqent until the concentrations of hydrosen 

and hydroxyl-ions in solution are approximately eqial. 

Nitrification - The conversion of nitrogenous matter into 

nitrates by bacteria. 

Nonionic Surfactant - A general family of surfactants so 

called because in solution the entire molecule 

remains associated. Nonionic molecules orient themselves at surfaces not by an electrical charge, but 

through separate grease-solubilizing and water-soluble 

groups within the molecule. 

Nonsettleable Matter - The suspended matter which does not 

sett1.e nor float to the surface of water in a period 

of one hour. 

Nonsettleable Solids - Wastewater matter that will stay in 

suspension for an extended period of time. Such 

period may be arbitrarily taken for testing purposes 

as one hour. 

Notch - An opening in a dam, spillway, or measuring weir 

for the passage of water. 
DRAFT 

Nozzle - (1) A short, cone-shaped tube used as an outlet 

for a hose or pipe. The velocity of the merging 

stream of water is increased by the reduction in 

cross sectional area of the nozzle (2) a short piece 

of pipe with a flange on one end and a saddle flange 

on the other end. 

Nutrients - Materials which are considered to be essential 

to support biological 1 ife. 

Odor Control - The elimination of odor-causing valatile 

substances associated with organic matter, living 

organisms, and cases. The most common, control 

measurement in use are the application of activated 

carbon residual chlorination, chlorine dioxide, ozone 

and aeration. 

Odor Threshold - The point at which after successive dilutions with odorless water, the odor of a water sample 

can just be detected. he threshold odor is expressed 

quantitatively by the number of times the sample is 

diluted with odorless water. 

Oil and Grease - Those materials which areextractable from 

wastewater with hexane, chloroform if other content of 

these specific solvents pollutants in water or wastewater (in mg/l or ppm) which can significantly influence 

the environment. 

Open-Channel Flow - Flow of a fluid with its surface exposed 

to - - the atmos~here. The conduit may be an open channel 

or a closed conduit flowing partly"full. 

Op_erators Qua1 ifications, Treatment Plant - Usually defined 

by a licence issued by local authorities. 

Organic Matter - Chemical substances of animal or vegetable 

origin, or more correctly of basically carbon structure, comprising compounds consisting of hydrocarbons 

and their deviations. 

Organic Nitrogen - Nitrogen combined in organic molecules 

such as protein, amines, and amino acids. 

Orifice - (1) An opening with closed perimeter, usually of 

regular form, in a plate, wall, or partition, through 

which water may flow generally used for the purpose 

of measurement orcontrol of such water. The edge 

may be sharp or of another configuration (2) the end 

of a small tube such as a Pitot tube. 
DRAFT 

Qrifice Plate - A plate containing an orifice. In pipes, 

the plate is usually inserted between a pair of 

flanges, and the orifice is smaller in area than the 

cross section of the pipe. 

Orthophosphate - An acid or salt containing phosphorus 

as PO4. 

Outfall - The point or location where sewage or drainage 

discharges from a sewer, drain, or conduit. 

Overflow Storm - A weir, orifice, or other device for 

permittinq the discharqe from ,a combined sewer of that 

part of the flow in excess of that which the sewer 

is designed to carry. 

Oxidation - The addition of oxygen to a compound. More 

generally, any reaction which involves the loss of 

electrons from an atom. 

Oxidation Pond - A basin used for retention of wastewater 

before final disposal, in which biological oxidation 

of organic material is effected by natural or 

artifically accelerated transfer of oxygen to the. 

water from air. 

Oxidation Reduction Potential (ORP) - The potential required 

to transfer electrons from the oxidant to the reductant 

and used as a qualitative measure of the state of 

oxidation in wastewater treatment systems. 

Oxygen Consumed - The quantity of oxygen taken up from 

potassium permananganate in.solution by a liquid 

containing organic matter. Commonly regarded as an 

index of the carbonaceous matter present. Time and 

temperature must be specified. 

Oxygen Dissolved - Usually designated as DO. The oxygon 

dissolved-in sewage wat'er, or other liquid usuqlly 

expressed in parts per million or percent of saturati on. 

Ozone - Oxygen in molecular form with three atoms of oxygen 

forming each molecule. Atmospheric oxygsn is in 

molecular form but each molecule contains two atoms 

of oxygen. Ozone is formed by passing high voltage 

electric charges through dry air. The third atom 

of oxygen in each molecule of ozone is loosely bound 

to it and is easily released. 
DRAFT 

Parshall Flume - A calibrated device developed by Parshall 

for measuring the flow of liquid in an open conduit. 

It consists essentially of a contracting length, a 

throat, and an expanding length. At the throat is 

a sill over which the flow passes as critical depth. 

The upper and lower heads are each measured at a 

definite distance from the sill. The lower head 

not be measured unless the sill is submerged more than 

about 67 percent. 

Pathogenic Bacteria - Bacteria which may cause disease in 

the organisms by their parasitic growth. 

pH - The reciprocal of the logarithm of the hydrogen ion 

concentration. The concentration is the weight of 

hydrogen ions, in grams per liter of solution. Neutral 

water, for example, has a pH value of 7 and hydrogen 

ion concentration of 10.7. 

pH Adjustment - A means of maintaining the optimum pH 

through the use of chemical additives. Can be manual 

or automatic, or automatic with flow corrections pH 

adjustment is not a linear function. 

Phenolein A1 kal inity - A measure of the hydroxides 

~lus one half of the normal carbonates in aqueous 

;uspension. Measured by the amount of sulfuric acid 

required to bring the water to a pH value of 8.3, 

as indicated by a change in color of phenolphthalein. 

It is expressed in parts per million of calcium 

carbonate. 

Pitot Tube - A device for measuring the velocity of flowing 

fluid bv usinq the ve1ocit.y head of the stream as an 

index velocity. It consists essentially of an orifice 

held to point upstream and connected with a tube in 

which the impact pressure due to velocity head may be 

observed and measured. It also may be constructed with 

an upstream and downstream orifice, or with an orifice 

pointing upstream to measure the velocity head or 

pressure and piezometer holes in a coaxial tube to 

measure the static head or pressure, in which case the 

difference in pressure is the index of velocity. 

Pollution Load - A measure of the strength of a wastewater 

in terms of its solids or oxygen-demanding characteristics, or in terms of harm ,to receiving waters. 
DRAFT 

Pollution Water - The introduction into a body of water 

of substances of such character and of such auantity 

that its natural quality is so altered as to 'impairw 

its usefulness or render it offensive to the senses 

of sight, taste, or smell. 

Polyelectrolytes - Used as a coagulant or a coagulant aid 

in water and wastewater treatment (activated carbon 

is another coagulant aid). They are synthetic polymers having a high molecular weight. Anionic negatively charged. Nonionic carry both negative and positive 

charges,(Cationic postively charged (most popular). 

Pond, Sewaqe Oxidation - A pond either natural or artifical 

into which partly treated sewage or discharged and in 

which natural purification processes take place under 

the influence of sunlight and air. 

Pooling, Filter - The formation of pools of sewage on the 

surface of filters, caused by surface cloggings. 

Pore Volume (activated carbon) - The pore volume is the 

difference in the volumetric displacement by granular 

activated carbon in mercury and in helium at standard 

conditions. 

Preaeration - A preparatory treatment of sewage consisting 

of aeration to remove gases, add oxygen, or promote 

flotation of grease and aid coagulation. 

Prechlorination - (1) Chlorination of water prior to filtration. (2) Chlorination of sewage prior to treatment. 

Precipitation, chemical - (1) Precipitation induced by 

addition of chemicals (2) The process of softening 

water by the addition of lime and soda ash as the 

precipitants. 

Pretreatment - Any wastewater treatment process used to 

reduce pollution load partially before the wastewater 

is introduced into a main sewer system or delivered 

to a treatment plantbfor substantial reduction of the 

pollution load. 

Primary Treatment - A process to remove substantlally all 

floating and settleablesolids in wastewater and 

partially to reduce the concentration of suspended 

solids. 
DRAFT 

Probability Curve - A curve that expresses the cumulative 

frequency of occurrence of a given event, based on an 

extended record of past occurrences. The curve is 

usually plotted on specially prepared coordinate paper, 

with ordinates representing magnitude equal to, or 

less than, the event, and abscissas representing the 

probability, time, or other units of incidence. 

Process Activated Sludge - A biological sewage treatment 

process in which a mixture of sewage and activated 

sludge is agitated and aerated. he activated sludge 

is subsequentlyseparated from the treated sewage (mixed liquor) by sedimentation, and wasted or returned 

to the process as needed. The treated sewage overflows 

the weir of the settling tank in which separation from 

the sludge takes place. 

Process, Biological - The process by which the life activities 

of bacteria, and other microorganisms in thesearch for 

food break down complex organic materials into simple, 

more stable substances. Self-purification of sewage polluted streams, sludge digestion, and all so-called 

secondary sewage treatments result from this process. Also called biochemical process. 

Process, Oxidation - Any method of sewage treatment for the 

oxidation of the putrescible organic matter the usual 

methods are biological filtration, and the activated 

sludge process. 

Purification Degree - (1 ) A measure of the comp'leteness of 

destruction or removal of objectionable impurities. such as bacteria and hardness from water by natural 

means (self urifications]or'by treatment (2) A 

measure of ! he removal, oxidation, or destruction of 

solids organic matter, bacteria, or other specified substance effected by sewage treatment processes. 

- Putrefaction - Biological decomposition of organic matter 

accompanied by the production of foul-smelling associated with anaerobic conditions. 

Rate Oxidation - The rate at which the organic matter in 

sewage is stablized. 

Ratio Dosinq - The maximum rate of application of sewage 

to a filter on any unit of area, divided by the average 

rate of application on, that area. 
DRAFT 

Reactivation (activated carbon) - The removal of adsorbates 

from spent granular activated carbon which will allow 

the carbon to be reused. This is also called regeneration and reviyification. 

Reaeration Sludqe - The continous aeration of sludge after 

its intial aeration in the activated sludge process. 

Recirculation - The refiltration of all or a portion of the 

effluent in a high rate trickling filter for the purpose of incoming flow to reduce its strength. 

Reduction Overall - The percentage reduction in the final 

effluent as compared with the raw sewage. 

enation - The replenishment of oxygen in a stream 

R* 1 dilution water entering the stream (2) biological oxygenation through the activities of certain 

oxygen producting plants and (3) atmospheric reaeration. 

Reservoir - A pond, lake, tank, basin, or other space 

either natural in origin or created in whole or in 

part by building of engineering structures. It is 

used for storage, regulation, and control of water. 

Recorder - A device that makes a graph or other automatic 

record of the stage, pressure, depth, velocity, or 

the movement or position of water controlling devices, 

usually as a function of time. 

Recovery Products - Substances regarded as wastewater 

pollutants which are recovered for their potential 

value through sale or reuse; recovery often is used 

-to lower or partially offset treatment (or recovery) 

costs. 

Rectangular Weir - A weir having a notch that is rectangular in shape. 

Reduction Practices - (7) Wastewater reduction practices 

can mean the reduction of water usage to lower the 

volume of wastewater requiring treatment and (2) the 

use of chemical reductant materials to lower the 

valance state of a specific wastewater pollutant. 

Reduction Treatment - The opposite of oxidation treatment 

where in a reductant (chemical is used to lower the 

valence state of a poilutant to a less toxic form 

e.g, the use of SO2 to "reduce" chromium +6 to 

chromium +3 in an acidic solution. 
DRAFT 

Refractory Organics - Organic pollutants which are chemically 

quite stable or resistant to treatment or biological 

oxidation, e.g. DDT pesticide. 

Residual Chlorine - Chlorine remaining in water or wastewater at the end of specified contact period as 

combined or free chlorine. 

Salinity - (1) The relative concentration of salts, usually 

sodium chloride, in a given water. It is usually 

expressed in terms of the number of parts per million 

of chloride (C1). (2) A measure of the concentration 

of dissolved mineral substances in water. 

Sampler - A device used with or without flow measurement 

to obtain an aliquot portion of water or waste for 

analytical purposes. May be designed for taking a 

sing1 e sample (grab), composite sample, continous 

sample, periodic sample. 

Sanitary Sewer - A sewer that carries liquid and watercarried wastes from residences, commercial buildinqs, - - 

industrial plants, and institutions together with 

minor quantities of ground-storm, and surface waters 

that are not admitted intentionally. 

Screen - (1) A device with openings, generally of uniform 

size, used to retain or remove suspended or floating 

solids in flowing water or wastewater and to prevent 

them from entering an intake or passing a given point 

in a conduit. The screening element may consist of 

para1 1 el bars, rods, wires , grating, wire mesh, or 

perforated plate, and the openings may be of any 

shape, although they are usually circular or rectangular. 

(2) A device used to segregate granular material such 

as sand, crushed rock, and soil into various sizes. 

Secondary Settling Tank - A tank through which effluent 

from some prior treatment process flows for the 

purpose of- removing settleable sol ids. 

Secondary Wastewater Treatment - The treatment of wastewater 

by biological methods after primary treatment by sedimentation. 

Second Stage Biological Oxygen Demand - That part of the 

oxygen demand associated with the biochemical oxidation of nitrogenous material. As the term implies, the 

oxidation of the nitrogenous materials usually does 

not start until a portion of the carbonaceous material 

has been oxidized during the first stage. 
DRAFT 

Sedimentation - The process of subsidence and deposition 

of suspended matter carried by water, wastewater, or 

other liquids, by gravity. It is usally accomplished 

by reducing the velocity of the liquid below the point 

at which it can transport the suspended material. 

Also called settling. 

Seeding Sludge - The inoculation of undigested sewage solids 

with sludqe that has underqone decomposition for the 

purpose of introducing favorable organisms, thereby 

accelerating the intial stages of digestion. 

Sewage Combined - A sewage containing both sanitary sewage 

and surface or storm water with or without industrial 

wastes. 

Sewage Dilute - Sewage containing less than 150 ppm of 

suspended solids and BOD (weak sewage). 

Sewage Industrial - Sewage in which industrial wastes predominate. 

Sewage Raw - Sewage prior to receiving any treatment. 

Sewage Settled - Sewage from which most of the settleable 

solids have been removed by sedimentation. 

Sewage Storm - Liquid flowing in sewers during or following 

a period of heavy rainfall and resulting therefrom. 

Sewer - A pipe or conduit, generally closed, but normally 

not flowing full for carrying sewage and other waste 

1 iquids. 

Sewer Intercepting - A sewer which receives dry-weather 

flow from a number of transverse sewers or outlets, 

and fequently additional, predetermined quantities of 

storm water (if from a combined system) and which 

conducts such waters to a point for treatment or disposal. 

Semipermeable Membrane - A barrier, usually thin, that permits passaqe of particles up to a certain size or of 

special nature. ' Often used' to separate colloids from 

their suspending liquid, as in dialysis. 
DRAFT 

Settleable Solids - (1) That matter in wastewater which will 

not stay in suspension during a preselected settling 

period, such as one hour, but either settles to the 

bottom or floats to the top. (2) In the Imhoff cone 

test, the volume of matter that settles to the bottom 

of the cone in one hour. 

Skimming Tank - A tank so designed that floating matter will 

rise and remain on the surface of the wastewater until 

removed, while the liquid discharges continously under 

certain walls or scum boards. 

Sludge - The solids (and accompanying water and organic 

matter) which are separated from sewage or industrial 

wastewater in treatment plant facilities. Sludge 

separation and disposal is one of the major expenses 

in wastewater treatment. 

Sludge Conditioning - A process employed to prepare sludge 

for final disposal can be thickening, digesting, heat 

treatment etc. 

Sludge Digestion - The process by which orqanic or volatile 

matter in sludge is gasified, liquified, mineraliz'ed, 

or converted into more stable organic matter through 

the activities of either anaerobic or aerobic organisms 

Sludge Disposal - The final disposal of solid wastes including the use of sewage sludges as fertilizers and soil 

builders; dumping sludge at sea; and filling lowlying lands. 

Sludge thickening - The increase,in solids concentration 

of sludge in a sedimentationor digestion tank. 

Spills - A chemical or material spill is an unintentional 

discharge of more than 10 percent of the sewage daily 

usage of a regularly used substance. In the case 

of a rarely used (one per year or less) chemical or 

substance, a spill is that amount that would result 

in 10% added loading to the normal air, water or solid 

waste loadings measured as the closest equivalent 

pollutant. 

Stabilization Laqoon - A shallow pond for storage of wastewater before discharge. Such lagoons may serve only 

to detain and equalize wastewater composition before 

regulated discharge to a stream, but often they are 

used for biological oxidation. 
DRAFT 

Stabilization Pond - A type of oxidation pond in which 

biological oxidation of organic matter is effected 

by natural or artifically accelerated transfer of 

oxygen to the water from air. 

Staff Gauge - A graduated scale, vertical unless otherwise 

specified, on a plank, metal plate, pier, wall etc., 

used to indicate the height of a fluid surface above 

a specified point or datum plane. 

,Stage Discharge Relation - The relation between gauge height 

and discharge of a stream or conduit at a gauging 

station. This relation is shown by the rating curve 

or rating table for such stations. 

Static Head - (1) The total head without reduction for 

velocity head or losses; for example, the difference 

in the elevation of headwater and tail water of a 

power plant. (2) The vertical distance between the 

free level of the source of supply and the point of 

free discharge or the level of the free surface. 

Steady Flow - (1) A flow in which the rate or quantity of 

water passing a given point per unit of time remains 

constrant. (2) Flow in which the velocity vector doer 

not change in either magnitude or direction with 

respect to time at any point or section. 

Steady Uniform Flow - A flow in which the velocity and the 

quantity of water flowing per unit remains constant. 

Stilling Well - A pipe, chamber, or compartment with compartively small inlet or inlets communicating with a 

main body of water. Its purpose is to dampen waves 

or surges, while permitting the water level within 

the well to rise and fall with the major fluctations 

of the main body of water. It is used with watermeasuring devices to improve accuracy of measurement. 

Submerqed Weir - A weir that when in use, has the water 

level on the downstream side at an elevation equal 

to or higher than, the weir crest. The rate of discharge is affected by the tail water. Also called 

drowned weir. 

Suppressed Weir - A weir with one or both sides flush with 

the channel of approach. This prevents contraction 

of the nappe adjacent to the flush side, The suppression may occur on one end or both ends. 
DRAFT 

Surveys - The gathering of numerical and other forms of 

data from the field, or plant site for the subsequent 

purpose of data reduction, correlation and analysis 

leading to improve water supply, treatment, use and 

wastewater treatment, described in total as a Water 

Management Program. 

Suspended Matter - (1) Solids in suspension in water, 

wastewater or effluent. (2) Solids in suspension that can be removed readily by standard filtering 

procedures in a laboratory. 

- Suspended Sol ids - (1) Solids that either float on the 

surface of, or are in suspension in water, wastewater, 

or other liquids, and which are largely removable by - 

laboratory filtering. (2) The quantity of material 

removed from wastewater in a laboratory test, as 

prescribed in "Standard Methods for the Examination 

of Water and Wastewater" and referred to as nonfilterable residue. 

Tertiary Treatment - A process to remove practically all 

solids and orsanic matter from wastewater. Granular 

activated carbon filtration is a tertiary treatment 

process. Phosphate removal by chemical coagulation 

is also regarded as a step in tertiary treatment. 

Threshold Odor - The minimum odor of the water sample that 

can just be detected after successive dilutions with 

odoriess water. Also called odor threshold. 

Titra.tion - The determination of a constituent in a known 

volume of solution by the measured addition of a solution of known strength to completion of the reaction 

as signaled by observation of an end point. 

Total Organic Carbon (TOC) - TOC is a measure of the amount 

of carbon in a sample orisinatins from orsanic matter 

only. The test is run by burningVthe sampie and 

measuring the CO produced. 

Total Solids - The total amount of solids in a waste water 

in both solution and suspension. 

Tracer - (1) A foreign substance mixed with or attached to 

a given substance for the determination of the location or distribution of the substance. (2) An element 

or compound that has been made radioactive so that it 

can be easily followed (traced) in biological and 

industrial processes. Radiation emitted by the 

radioisotope pinpoints its location. 
DRAFT 

Treatment Efficiency - Usually refers to the percentage 

reduction of a specific or group of pollutants by a 

specific wastewater treatment step or treatment plant. 

Turbidmeter - An instrument for measurement of turbidity, in 

which a standard suspension usually is used for 

reference. 

Turbidity - (1) A condition in water or wastewater caused 

by the presence .of suspended matter, resulting in the 

scattering and absorption of light rays. (2) A measure 

of fine suspended matter in liquids. (3) An analytical 

quantity usually reported in arbitrary turbidity units 

determined by measurements of light diffraction. 

Turbulent Flow - (1) The flow of a liquid past an object 

such that the velocity at anv fixed point in the fluid 

varies irregularly. (2) A type of liquid flow in which 

there is an unsteady motion of the particles and the 

motion at a fixed point varies in no definite manner. 

Sometimes called eddy flow, sinuous flow. 

Ultimate Biochemical Oxygen Demand - (1) Commonly, the total 

quantity of oxygen required to satisfy completely the 

first-stage biochemical oxygen demand. (2) More strickly, 

the quantity of oxygen required to statisfy completly 

both the first-stage and the second-stage biochemical 

oxygen demands. 

Velocity Area Method - A method used to determine the discharge of a stream or any open channel by measuring 

the velocity of the flowing water at several points 

within the cross section of the stream and summing up 

the products of these velocities and their respective 

fraction of the total area. 

Velocity Meter - A water meter that operates on the principle that the vanes of the wheel move at approximately 

the same velocity as the flowing water. 

Velocity of Approach - The mean velocity in a conduit immediately upstream from a weir, dam, venturi tube, 

or other structure. 

Vena Contracta - The most contacted sectional area of a 

stream jet, or nappe issuing through or over an orifice 

or weir notch. It occurs downstream from the plane 

of such notch or orifice. 
DRAFT 

Venturi Flume - A open flume with a contracted throat that 

causes a drop in the hydraulic grade line. It is used 

for measuring flow. 

Venturi Meter - A differential meter for measuring flow of 

water or other fluid through closed conduits of pipes, 

consisting of a venturi tube and one of several proprietary forms of flow-registering devices. The difference in velocity heads between the entrance and the 

contracted throat is an indication of the rate of 

flow. 

Venturi Tube - A closed conduit or pipe, used to measure 

the rate of fluids, containing a gradual contraction 

to a throat, which causes a pressure-head reduction 

by which the velocity may be determined. The contraction is usually, but not necessarily, followed by 

an enlargement to the original size. 

Volatile Solids - The quantity of solids in water, wastewater or other liquids, lost on ignition of the 

dry solids at 600°C. 

Wastewater Survey - An investigation of the quality and 

characteristics of each waste stream, as in an industrial 

plant or municipality. 

Water Level Recorder - A device for producing, graphically 

or otherwise, a record of the rise and fall of a water 

surface with respect to time. 

Water Meter - A device installed in a pipe under pressure 

for measuring and registering the quantity of water 

passing through it. 

Water Renovation - Wastewater treatment of sufficient degree 

to allow the reuse of water for one or more purposes 

in a given water supply/treatment system. 

Weir - (1) A diversion dam. (2) A device that has a crest 

and some side containment of known geometric shape, 

such as a V, trapezoid, or rectangle and is used to 

measure flow of liquid. The liquid surface is exposed 

to the atmosphere. Flow is related to upstream height 

of water above the crest, to position of crest with 

respect to downstream water surface, and to geometry 

of the weir opening. 
DRAFT 

APPENDIX C 

EFFECT OF POLLUTANT PARAMETERS ON 

TREATMENT WORKS 

pH, ACIDITY AND ALKALINITY 

Most bacteria (and other protists) that are essential to the 

operation of a biological treatment system cannot bear pH 

levels above 9.5 or below 5.0. The pH range for optimum 

growth generally lies between 6.5 and 7.5. Depending on the 

volume of a particular waste and the acidity or alkalinity 

of the waste in the treatment unit, an incoming waste of 

extreme pH could have a substantial adverse effect on a 

treatment unit. 

Acidity 

Highly acid wastes can exhibit the same detrimental effects 

on microorganisms as wastes of low pH. The acidity of an 

incoming waste is particularly important in operation of 

anaerobic digesters, where the pH for optimum operation is 

6.6 to 7.6. An incoming waste of high acidity that causes 

the pH of an anaerobic system to drop below 6.2 will severely 

upset operation of the unit. Wastes of high acidity are 

also corrosive to the metals and concrete that make up the 

structure of any treatment unit. 

Alkalinity 

A waste of high alkalinity can have a severe effect on the 

operation of a treatment unit, not only causing the death of 

microorganisms, but also causing the corrosion of structural 

materials. 

-- OIL AND GREASE 

Oils and grease can cause problems with scum formation in 

wet wells and clarifiers. Mineral oils in particular can 

coat solid particles that are present in wastes. The 

particles hinder biological activity and increase maintenance 

problems. Free oil (as measured by CC74 extraction) has 

reportedly interfered with aerobic biological treatment 

at concentrations of 50-100 mg/l (1). 
DRAFT 

CHEMICAL OXYGEN DEMAND (COD) 

Since the COD analysis is sensitive to compounds that are 

toxic to biological life as well as those that are not, a 

waste of high COD can be potentially harmful to treatment 

systems if toxins are present. The potential for harm of a 

high COD waste would remain unknown without either detailed 

chemical analysis of the waste or experimentation with the 

waste on a laboratory-scale biological treatment system. 

CHROMIUM (Cr) 

Moore, et a (2), have studied the effects of hexavalent 

chromium (in the form of potassium chromate) on 

laboratory-scale activated sludge systems and laboratory 

scale anaerobic digesters. Their results for activated 

sludge systems showed that continuous Cr+6 concentrations 

at and below 15 mg/l in the sewage feed had no significant 

effect on overall BOD and COD removal. A continuous dose 

of 50 mg/l of Cr+6 reduced BOD removal efficiency by 

three percent over that of a control unit and COD removal 

efficiency by four percent, but the authors attach limited 

significance to this result. Continuous doses of chromium 

containing primary and secondary sludge from the activated 

sludge system to the anaerobic digesters had no effect on 

anaerobic gas production at concentrations of Cr+6 in the 

sludge of 3.0 mg/l, 5.8 mg/l, and 30 mg/l. 

The authors also studied the effects of slug doses of Cr+6 

on the aforementioned .systems. The sludge doses were fed 

to the activated sludge systems over a four hour period of 

time in the amounts of 10 mg/l, 100 mg/l and 500 mg/l. No 

effect on performance was noted with the 10 mg/l dose. The 

I00 mg/l dose caused a drop of three percent in the BOD removal 

efficiency and a greater drop in the COD removal efficiency, 

with a rapid recovery. The 500 mg/l dose caused a drop in 

BOD removal efficiency of 11 percent and a drop in the 

COD removal efficiency of 13 percent. The decreased 

efficiency lasted for 32 hours, and was followed by a gradual 

recovery. Slug doses were also added to digesters that had 

previously received chromium containing sludge. A slug dose 

of 300 mg/l caused gas production to cease for seven days, 

followed by gradual recovery. A slug dose of 500 mg/l 

ceased gas production permanently. The authors point out 

that the likelihood of digesters receiving slug doses of 

these magnitudes is extremely remote. 
DRAFT 

The authors' results also show that the removal efficiency 

of chromium by the activated sludge process can vary greatly, 

depending on the chromium concentration in the influent. 

Reported Cr+6 removals varied from approximately 78 percent 

to 17 percent when the Cr+6 influent concentration was 

50.0 mg/l to 0.5 mg/l respectively. 

Other researchers have performed studies on nitrification. 

Whiteland, et (I), in a study of the effects of 

hexavalent chromium on the nitrification process, have 

reported that the process was severely affected at Cr+6 

concentrations in raw sewage on the order of 2 mg/l to 

5 mg/l. 

COPPER (Cu) 

McDermott, -- et a1 (2), have investigated the effects 

of copper in the form of copper sulfate and in the form of 

a copper cyanide complex (Nan Cu(CN)n) on bench scale 

activated sludge systems and-bench scale anaerobic digesters. 

Studies were conducted on the effects of both continuous 

and slug doses of these two forms of copper on BOD and COD 

removal efficiency of the activated sludge systems, and on 

the effects of continuous doses of copper sulfate, continuous 

doses of copper cyanide complex, and slug doses of copper 

sulfate on gas production from the anaerobic digesters. 

The results for continuous doses to activated sludge systems 

showed that 10-25 mg/1 of copper sulfate in the influent 

reduced BOD and COD removal efficiency by an average of 

four percent, and that 5-10 mg/l of the copper cyanide 

complex reduced BOD and COD removal efficiency by as much as 

six percent. Differences in effects of the two forms of 

copper disappeared after the system acclimated to the copper 

and cyanide. Slug doses of copper sulfate to the activated 

sludge system of 66 mg/l over a four-hour period had only 

a small effect on BOD and COD removal efficiency, but doses 

of 100 mg/l caused a 50 percent reduction in BOD removal 

efficiency and larger doses up to 410 mg/l had somewhat 

greater effects. All of the systems recovered after a 

maximum of 120 hours. Smaller slug doses of the copper 

cyanide complex had a much more severe initial effect than 

the copper sulfate, but the systems recovered in only 24 hours 

with doses up to 25 mg/l. Anaerobic digesters that were fed 

combined primary and secondary sludge from activated sludge 

units that were receiving 10-25 mg/l of copper sulfate and 

10 mg/l of the copper cyanide complex experienced subnormal 

gas production. Slug doses of copper sulfate of as much as 

410 mg/l had no effect on digester performance. The authors 

also report that the activated sludge process is 79 to 50 

percent efficient in the removal of both forms of copper when 
DRAFT 

the copper concentration in the influent is 0.4 to 25 mg/l. 

Studies on the effect of copper on the nitrification process 

have been conducted by Kalabina, -- et a1 (1). The authors 

report that copper at concentrations of 0.5 mg/l inhibited 

nitrification when the copper was fed in the form of copper 

sulfate. 

CYANIDE (CN) 

It has been reported that 1.0-2.0 mg/l of cyanide (as HCN) 

in influent sewage had an effect on the performance of 

activated sludge units, trickling filters, and anaerobic 

digesters, and that 2.0 mg/l of cyanide inhibited the 

nitrification process. Higher levels of tolerance of 

activated sludge units and trickling filters have been 

reported by other authors. Interference with the activated 

sludge process has been reported at cyanide concentrations 

in raw sewage of 5 mg/l. Studies on trickling filter 

performance have reported that 30 mg/l of cyanide in the 

influent to trickling filters produced an effluent of poor 

quality, but that cyanide concentrations of 10 mg/l can be 

destroyed almost completely. Other studies have reported 

that secondary biological treatment processes, if acclimatized 

to cyanide, can effectively oxidize it (1). 

-- IRON (Fe) 

Iron is a necessary nutrient for microbial growth, and has no 

effect on the activated sludge process except at very high 

concentrations (on the order of 1000 mg/l). The effect of 

iron on the sludge digestion process has been reported (to be 

much greater. Iron levels above 5 mg/l in digesters have 

caused interference with the process, due to the release of 

acidity when the iron is hydrolyzed (3). 

NICKEL (Ni) 

McDermott, et a1 (2) have conducted studies on the 

effect of nickel sulfate additions to bench scale activated 

sludge units and anaerobic digesters. Continuous doses of 

nickel to activated sludge units ranging from 2.5-10 

mg/l reduced BOD removal efficiency by a maximum of five 

percent and increased the turbidity of the effluent. A 

200 mg/l slug dose of nickel seriously reduced treatment 

efficiency for a few hours, but the activated sludge process 

recovered completely within 40 hours. Combined primary and 

secondary sludge from an activated sludge process receiving 
DRAFT 

10 mg/l of nickel digested satisfactorily in anaerobic 

digesters, and primary sludge from a unit receiving 

40 mg/l continously digested satisfactorily. It was 

reported that the activated sludge process is approximately 

30 percent efficient in the removal of nickel. 

With respect to nitrification, it has been reported that 

severe inhibition of the process is experienced at a 

nickel concentration of 0.5 mg/l (1). 

PHOSPHORUS 

Phosphorus is not harmful to treatment works, and is 

actually a necessary nutrient for adequate bacterial 

growth. If phosphorus is not completely removed during 

wastewater treatment, however, it can have harmful effects 

upon the receiving water (as discussed under Section VI). 

ZINC (Zn) 

McDermott, et a1 (Z), have reported the effects of 

zinc on activated sludge treatment and anaerobic digestion. 

Zinc sulfate and zinc complexed with cyanide had similar 

effects when fed continously to a laboratory-scale 

activated sludge process. At concentrations ranging from 

2.5 to 20 mg/l both substances reduced BOD removal 

efficiency by a maximum of two percent after the activated 

sludge became acclimated. The maximum zinc concentration 

that will produce no significant effect on treatment 

efficiency was reported as greater than 2.5 mg/l and less 

than 10 mg/l. A 160 mg/l slug dose of zinc fed to the 

activated sludge unit over a period of four hours caused 

a drastic reduction in treatment efficiency for about one 

day, but the unit recovered completely after 40 hours. 

Combined primary and secondary sludge from activated 

sludge units receiving 10 mg/l of zinc continuously (as 

ZnS04) digested suitably in anaerobic digesters. Sludge 

from-activated sludge units that were fed 20 mg/l caused 

rapid failure of the digestion units. The activated 

sludge process is reported as being from 95 to 74 percent 

efficient in removing zinc when fed sewage with zinc concentrations from 2.5 mg/l to 20 mg/l respectively. 

Other authors have reported that the concentration of zinc 

in influent sewage should be less than 5 mg/l to prevent 

decreases in gas production in anaerobic digestion, 

and that zinc concentrations of 0.5 mg/l will inhibit the 

nitrification process (1 ). 
DRAFT 

SYNERGISM AND ANTAGONISM 

Synergism 

The increase in the toxic effect of one substance caused by 

the presence of another substance is called synergism. 

Synergistic effects are particularly important when considering metals, since most metals are soluble at low pH 

values and insoluble at high pH values. Thus acidity can 

exert a synergistic effect by contributing to the release 

of metals into solution, where they can be ingested by 

microorganisms. 

Reference 3 contains a discussion of the synergistic 

effects of cadmium, chromium, copper, iron, and zinc, 

which is summarized below: 

Cadmium - Zinc and manganese have been reported to have 

synergistic effects with cadmium. It is certain that acidity 

would also have a synergistic effect. 

Chromium - Iron, copper, and acidity have been reported to 

have synergistic effects with chromium. 

Copper - Synergism with cyanide, acidity, and other heavy 

metals has been reported. 

Iron - Synergism of iron with chromium has been reported 

and synergistic effects with other metals may also occur. 

Zinc - Synergistic effects have been reported with the 

following: 10 mg/l of cadmium with 1 mg/l of zinc, 10 mg/l 

of cadmium with 10 mg/l of zinc, and 100 mg/l of manganese 

with 10 mg/l of zinc. 

Antagonism 

Antagonism is the opposite of synergism, and is thus the 

decrease in the toxic effect of one substance caused by 

the presence of another. Dramatic antagonistic effects 

on metals are caused by chelating agents, of which EDTA 

(disodium salt of ethylene diamine tetracetic acid) and 

HEDTA (disodium salt of hydroxyethylenediamine triacetic 

acid) are examples. 

Sulfide can exhibit antagonistic effects with metals in 

sludge digesters. This effect is probably responsible for 

much of the ambiguity in the literature of the effects of 

metals on sludge digestion. The, antagonistic effect 

is due to the fact that sulfide precipitates metals, thus 

taking them out of solution, and preventing their assimilation 

by microorganisms. Other ions have similar effects on 
DRAFT 

metals; examples are: hydroxide (high pH), chromate, 

ferrocyanide, phosphate, carbonate, and arsenate (17). 

A summary of the antagonistic effects of cadmium, copper, 

and iron follows: (3). 

Cadmium - Sulfide and high pH (8 and higher) are antagonistic 

wth cadmium. 

Copper - Sulfide, high pH and certain chelating agents (such 

as EDTA) are antagonistic with copper. 

Iron - Sulfide and high pH are antagonistic with iron. 

Additionally, an antagonistic effect would be expected with 

cyanide, since the ferrocyanide complex is very stable. 
DRAFT 

REFERENCES 

1. U.S. Environmental Protection Agency, "Pretreatment 

- of pollutants introduced into publicly-owned 

treatment works, Office of Water Program Operations, 

Washington, D.C., (October, 1973). 

2. U.S. Department of Health, Education and Welfare, 

Interaction of Heavy Metals and Biological Sewage 

Treatment Processes, Pub1 ic Health Service, Division 

of Water Supply and Pol 1 ution Control, Cincinnati, 

Ohio (May, 1975). 

3. U.S. Environmental Protection Agency, State and Local 

Pretreatment Programs, (Draft Federal Guidelines), 

Office of Water Program Operations, Washington, D.C., 

(August, 1975). 
METRIC UNITS 

CONVERSION TABLE 

MULTIPLY (ENGLISli UNITS) by 

ENGLISH UNIT 

acre 

acre - feet 

British Thermal 

Unit 

British Thermal 

Unic/pound 

cubic feet/minute 

cubic feet /second 

cubic feet 

cubic feet 

cubic inches 

degree Fahrenheit 

feet 

gallon 

gallon/minute 

horsepower 

inches 

inches of mercury 

pounds 

million gallons/day 

mile 

poundlaquare 

inch (gauge) 

square feet 

square inches 

tons (ehort) 

yard 

ABBREVlATXON CONVERSION 

ac 

ac ft 

BTU 

BTU/~ 

cfm 

cfs 

cu ft 

cu ft 

cu in 

Fa 

f t 

gal 

gpm 

hp 

in 

in Hg 

lb 

mgd 

mi 

psi8 

sq ft 

sq in 

t 

Y 

TO OBTAIN (METRIC UNITS) 

ABBREVIATION 

kg cal 

(0.06805 psig -1-1)" 

0.0929 

6.452 

0.907 

0.9144 

* Actual conversion, not a multiplfet 

"C 

m 

1 

l/sec 

kw 

cm 

atrn 

kg 

cu m/day 

km 

atm 

sq m 

sq cm 

kkg 

m 

METRIC UNIT 

hectares 

cubic meters 

kilogram - calories 

kilogram calories/l:ilogxa~n 

cubic tneters/minute 

cubic meters/minute 

cubic meters 

liters 

cabic centimeters 

degree Centigrade 

meters 

liters 

lfters/second 

killowatts 

centimeters 

atmospheres 

kilograms 

cubic meterslday 

kilometer 

atmospheres (absolute) 

square meters 

square centimeters 

metric tons (1000 kilograms) 

meters 

4U.S. GOVERNMENT PRINTING OFFICE:1974 582-414/82 1.)