.Office Of Water
Environmental _Protection _(EN-336) •
21W-4004
July 1991
Matjona^l Pretreatment Program
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UNITED STATES ENVIRONMENTAL-PROTECTION AGENCY
WASHINGTON, O.C. 20460
, :,•
JUL 10 1991 '
THE ADMINISTRATOR •
Honorable J. Danforth Quayle
President of the Senate
United States Senate
Washington, D.C. 20510 ;
Dear Mr. President:
I am pleased to present the Environmental Protection
Agency's Report to Congress on the National Pretreatment Program.
This Report responds to Section 519 of the Water Quality Act of
1987, which required EPA to study certain elements of the
National Pretreatment Program. The National Pretreatment Program
is a joint regulatory effort by EPA, States, and municipalities
to ensure that nondomestic discharges of pollutants to municipal
wastewater treatment plants ("publicly owned treatment works," or
POTWs) do not interfere with POTW operations, pass through to
receiving Waters, or contaminate sewage sludge.
Section 519 required EPA to study the following:
(a) STUDY. The Administrator shall study—
(1) the adequacy of data on environmental impacts
of toxic industrial pollutants from publicly
owned treatment works;
(2) the extent to which secondary treatment at
publicly owned treatment works removes toxic
pollutants;
(3) the capability of publicly owned treatment
works to revise pretreatment requirements
under section 307(b)(l) of the Federal Water
Pollution Control Act;
(4) possible alternative regulatory strategies
for protecting the operations of publicly
owned treatment works from industrial
discharges, and shall evaluate the extent to
which each such strategy identified may be
expected to achieve the goals of this Act;
(5) for each such alternative regulatory
strategy, the extent to which removal of
toxic pollutants by publicly owned treatment
works results in contamination of sewage
sludge and the extent to which pretreatment
i
' • . ' Printed on Recycled Paper
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•requirements may prevent such contamination or
improve the ability of publicly owned treatment
works to comply with sewage sludge criteria
developed under section 405 of the Federal Water-
Pollution Control Act; and
(6) the adequacy of Federal, State, and local
resources to establish, implement, and
enforce multiple pretreatment limits for
toxic pollutants for each such alternative
strategy.
(b) REPORT. Not later than 4 years after the date of
the enactment of this Act, the Administrator shall
submit a report on the results of such study along with
recommendations for improving the effectiveness of
pretreatment requirements to the Committee on Public
Works and Transportation of the House of
Representatives and the Committee on Environment and
Public Works of the Senate.
This Report to Congress accomplishes that mandate. It
examines what is known about discharges of toxic pollutants to
publicly owned treatment works (POTWs),, the extent to which POTWs
remove toxic pollutants from wastewaters, and the environmental
effects of toxic pollutants released from POTWs to receiving
waters, sewage sludge, and air. It also evaluates how well the
National Pretreatment Program is being carried out, and examines
alternative regulatory strategies for improving the Program.
Finally, the Report recommends improvements to the Program that
will allow POTWs to better control toxic pollutant discharges and
meet the goals of the Clean Water Act (CWA).
The Report reaffirms the Federal, State, and local
government partnership that is unique to the National
Pretreatment Program. It finds that publicly owned treatment
works (POTWs) have made tremendous progress carrying out and
enforcing national and local pretreatment standards and
requirements. Many POTWs have achieved significant reductions in
toxic pollutant loadings to their treatment plants and subsequent
reductions of toxic pollutants in their effluents and sewage
sludges. . ,
The Report finds that additional work is necessary. States
and POTWs have been limited to some extent by the lack of
environmental standards and criteria that provide an important
basis for the Pretreatment Program and which allow us to
thoroughly demonstrate the environmental effectiveness of this
truly multi-media program. EPA is making good progress in
ensuring that States adopt water quality criteria for toxic
pollutants, is considering expansion of its criteria development
activities, and, along with States, is issuing water quality-
based NPDES permits. The Report also demonstrates that POTWs and,
industries are using pollution prevention as an important means
of reducing toxic pollutants to .and from POTWs.
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: . ' . .'.',•'''•' 3 '•"._, •'-.,.'
•-••._, .' r • - - •.
Lastly, the Report affirms the existing regulatory structure
of the National Pretreatment Program. It recommends improvements
to the Program within that structure that fall within three broad ,
categories:
i ' '-
« Continued development of national technology-based
discharge standards for industries and pollutants of
concern; . .
e strengthening of controls by individual POTWs over toxic
discharges; and '
e Continued development of criteria and standards, for
receiving environments, and limits in POTWs1 NPDES
permits to reflect such development, in order to help
POTWs assess their effects on receiving .environments and
provide appropriate site-specific controls on their
industrial dischargers.
I believe that this Report to Congress responds fully to the
mandate of Section 519 of the 1987 WQA, that it constitutes an
insightful and comprehensive examination of the National
Pretreatment Program, and that its findings and recommendations
are sound.
Sincerely yours,
William K. Reilly
Enclosure
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..
UNITED STATES INVIHONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
1 0 1991
„ ' , ,_ THE ADMINISTRATOR .
Honorable Thomas Foley '
Speaker of the House .
House of Representatives
Washington, D.C. 20515
Dear Mr. Speaker:
I am pleased to present the Environmental Protection
Agency's Report to Congress on the National Pretreatment Program.
This Report responds to Section 519 of the Water Quality Act of
1987, which required EPA to study certain elements of the
National Pretreatment Program. The National Pretreatment Program
is a joint regulatory effort by EPA, States, and municipalities
to ensure that nondomestic discharges of pollutants to municipal
wastewater treatment plants ("publicly owned treatment works;" or
POTWs) do not interfere with POTW operations, pass through to
receiving waters, or contaminate sewage sludge.
Section 519 required.EPA to study the following:
(a) STUDY. The Administrator shall study--
(1) the adequacy of data on environmental impacts
of toxic industrial pollutants from publicly
owned treatment works;
(2) the extent to which secondary treatment at
publicly owned treatment works removes toxic
pollutants;
(3) the capability of publicly owned treatment
works to revise pretreatment requirements
und«r section 307(b)(1) of the Federal Water
Pollution Control Act; .
(4) possible alternative regulatory strategies ,
for protecting the operations of publicly
owned treatment works from industrial
discharges, and shall evaluate the extent to
which each such strategy identified may be
expected to achieve the goals of this Act;
(5) for each such alternative regulatory
strategy, the extent to which removal of
toxic pollutants by publicly owned treatment
works results in contamination of sewage
sludge and the extent to which pretreatment
Printed on Recyaez
-------
requirements may prevent such contamination or
improve the ability of publicly owned treatment
works to comply with sewage sludge criteria
developed under.section 405 of the Federal Water
Pollution Control Act; and
(6) the adequacy of Federal, State, and local
resources to establish, implement, and
enforce multiple pretreatment limits for
toxic pollutants for each such alternative
strategy.
(b) REPORT. Not later than 4 years after the date of
the enactment of this Act, the Administrator shall
submit a report on the results of such study along with
recommendations for improving the effectiveness of
p"retreatment requirements to the Committee on Public
Works and Transportation of the House of
Representatives and the Committee on Environment and
Public Works of the Senate.
This Report to Congress accomplishes that mandate. It
examines what is known about discharges of toxic pollutants to
publicly owned treatment works (POTWs), the extent to which POTWs
remove toxic pollutants from wastewaters, and the environmental
effects of toxic pollutants released -from POTWs to receiving
waters, sewage sludge, and air. It also evaluates how well the
National Pretreatment Program is being carried out, and examines
alternative regulatory strategies for improving the Program.
Finally, the Report recommends improvements to the Program that
will allow POTWs to better control toxic pollutant discharges and
meet the goals of the Clean Water Act (CWA).
• . • . j ' i1 ' • ' • • '
The Report reaffirms the Federal, State, and local
government partnership that is unique to the National
Pretreatment Program. It finds that publicly owned treatment
works (POTWs) have made tremendous progress carrying out and
enforcing national and local pretreatment standards and
requirements. Many POTWs have achieved significant reductions in
toxic pollutant loadings to their treatment plants and subsequent
reductions of toxic pollutants in their effluents and sewage
sludges. .
The Report finds that additional work is necessary. States
and POTWs have been limited to some extent by the lack of
environmental standards and criteria that provide an important
basis for the Pretreatment Program and which allow us to
thoroughly demonstrate the environmental effectiveness of this
truly multi-media program. EPA is making good progress in
ensuring that States adopt water quality criteria for toxic
pollutants, is considering expansion of its criteria development
activities, and, along with States, is issuing water quality-
based NPDES permits. The Report also demonstrates that POTWs and
industries are using pollution prevention as an important means
of reducing toxic pollutants to and from POTWs,
t • ,
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Lastly, the Report affirms the existing regulatory structure
of the National Pretreatment Program. It recommends improvements
to the Program within that structure that fall within three broad
categories: - .
• Continued development of national technology-based
discharge standards for industries and pollutants of
, concern;
• Strengthening of controls by individual POTWs over toxic
discharges; and
• Continued development of criteria and standards for
receiving environments,, and limits in POTWs1 NPDES
permits to reflect such development, in order to help
POTW? assess their effects on receiving environments and
- provide appropriate site-specific controls on their
industrial dischargers.
I believe that this Report to Congress responds fully to the
mandate of Section 519 of the 1987 WQA, that it constitutes an
insightful and comprehensive examination of the National
Pretreatment Program, and that its findings and recommendations
are sound. '•'...;
Sincerely yours,
' William K. Reilly
Enclosure
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ACKNOWLEDGMENTS
This Report to Congress is the product of intensive effort, dedication, and team spirit.
Many individuals and organizations, beyond those mentioned here, contributed to this
product. Their contributions are greatly appreciated.
Two individuals, in particular, are responsible for managing and facilitating the
completion of this Report to Congress: Ross Brennan and Debora Clovis, of the Permits
Division. Ross and Debora provided the unending energy and enthusiasm that was the
trademark of this report. Section Chief Jeffrey Lape arid Branch Chiefs Ephraim King and Jim
Taft provided guidance, as did other EPA senior managers:, Cynthia Dougherty, Director,
Permits Division and James Elder, Director, Office of Water Enforcement and Permits.
Valuable support also was provided by numerous OWEP staff, including Pat Bradley, Jim
Collins, Louis Eby, Cristina Gaines, Marilyn Goode, John Hopkins, Andy Hudock, Lee
Okster, Linda Suttora, and George Utting. -
Extensive input and advice was provided by the EPA Work Group and the individual
representatives:
Roland Dubois, Office of General Counsel
David Hindin, Office of Enforcement %
Mahesh Podar, Office of Policy, Planning, and Evaluation
Woody Forsht, Office of Water Regulations and Standards
Eric Strassler, Office of Water Regulations and Standards
Henry Kahn, Office of Water Regulations and Standards
Rob Esworthy, Office of Water Regulations and Standards ~
Al Rubin, Office of Water Regulations and Standards
Bob Bastian, Office of Municipal Pollution Control
AtalEralp, Office of Municipal Pollution Control
» ' - •-•-.' .
Judy Hecht, Office of Water
Chuck Job, Office of Ground-Water Protection
Tim Kasten, Office of Marine and Estuarine Protection
Catherine Cekolin, Office of Marine and Estuarine Protection
Ken Dostal, Office of Research and Development
Jim Kreissel, Office of Research and Development
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Dan Murray, Office of Research and Development
Chieh Wu, Office of Research and Development
Don Tang, Office of Research and Development
Marc Turgeon, Office of Solid Waste
Pat Fox, Office of Solid Waste
Penny Lassiter, Office of Air Quality Planning and Standards
Special thanks are also extended to the EPA Regional Pretreatment Coordinators, State
Pretreatment Coordinators, and numerous POTWs for providing information for the Report.
Particular thanks go to the Hampton Roads Sanitation District, Virginia, City of Pocatello,
Idaho, and City of Thomasville, North Carolina, for serving as case studies.
Finally, Science Applications International Corporation (SAIC) of McLean, Virginia,
provided assistance to EPA during the preparation of this report under EPA Contract No.
68-C8-0066. Peter Trick and Jack Mozingo were the SAIC Work Assignment Managers.
Principal technical contributors were David Hair, Kathleen Hafrigan, Robert Kelly, Larry Lai,
Robert Linett, Karen McDonald, Maurice Owens, James Parker, Peter Trick, and Mary
Waldron. Data management support was provided by Lewis Pfister, Dung Phan, and George
Wilkie. Report production was managed by Margaret Siriano with assistance from Abby
Johnson, Cindy Marut, and Elisabeth Smeda.
Cover photo: S.C. Delaney/EPA
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TABLE OF CONTENTS
Section Page
EXECUTIVE SUMMARY ................... ........ E§- 1
l. BACKGROUND AND INTRODUCTION......... ,...„ ;.. i-i
l.l THE NATIONAL PEETREATMENT PROGRAM.., ........... l-i
1.1.1 Controls on POTWs Under the Clean Water Act 1-2
1.1.2 The Role of the National Pretreatment Program. ....,-, 1-4
1.1.3 Responsibilities for Implementing the National Pretreatment
Program................... 1-6
1.1.4 POTWs Required to Have Pretreatment Programs 1-8
1.1.5 Pretreatment Standards. ......... 1-11 v
1.1.6 Significant Industrial Users....... .....;...... 1-18
1.2 PREVIOUS ASSESSMENTS OF THE NATIONALPRETREATMENT
PROGRAM „.. i-is
1.2.1 Pretreatment Regulatory Impact Analysis.. 1-18
1.2.2 Assessment of Industrial Waste Control Programs in Three
Municipalities .............;. ..;. .-. 1-19
1.2.3 Pretreatment Implementation Review Task Force.... 1-20
1.2.4 Domestic Sewage Study.... ...; 1-20
1.2.5 General Accounting Office Report 1-22
1.2.6 Report to Congress on Hydrogen Sulfide Corrosion... 1-23
1.3 SUMMARY....... ; .'.....;. 1-24
1.4 • ORGANIZATION OF THIS REPORT TO CONGRESS.... 1-25
2. STUDY APPROACH AND DATA SOURCES .. 2-1
,2.1 APPROACH . „ 2-1
2.1.1 Multimedia Perspective ;. 2-2
2,1.2 Reliance on Existing Data........... ', 2-3
2.2 OVERVIEW OF DATA NEEDS...., ;.....„., 2-4, •
2.3 EXISTING DATA SOURCES. 2-4
2.4 USE OF MAJOR DATA SOURCES.. ;. ....;., „ 2-15
2.5 CASE STUDIES 2^18
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TABLE OF CONTENTS (continued)
i , ' i , •
Section Eag£
3. DISCHARGE OF TOXIC POLLUTANTS TOPOTWS 3-1
3.1 METHODOLOGY 3-1
3.1.1 Previous EPA Studies .. 3-1
3.1.2 Approach to Identifying Sources and Types of Toxic
Pollutants '. ....A- 3-2
3.1.3 Data Sources . , 3-3
3.2 INDUSTRIAL AND COMMERCIAL SOURCES OF TOXIC POLLUTANTS 3-6
3.2.1 Estimates of the Number of and Flow From Industrial and
Commercial Dischargers • 3-6
3.2.2 Industrial and Commercial Sources 3-16
3.3 DOMESTIC SOURCES OF TOXIC POLLUTANTS 3-50
3.3.1 Characterization of Domestic Wastewater 3-51
3.3.2 Potential Sources of Toxic Pollutants in Domestic
Wastewater ~ . 3-53
3.3.3 Evaluation of Domestic Loadings of Toxic Pollutants 3-60
3.4 OTHER SOURCES OF TOXIC POLLUTANTS 3-65
3.4.1 Storm-Water Sources... . 3-65
3.4.2 Infiltration/Inflow Sources 3-73
3.4.3 Waste Haulers :.' 3-74
3.4.4 RCRA and CERCLA Activities.......... 3-76
3.5 CASE STUDIES ,....:... 3-83
3.6 POLLUTION PREVENTION INITIATIVES ,. 3-85
3.7 FINDINGS «....' 3-93
3.7.1 Industrial and Commercial Sources 3-93
3.7.2 Domestic Sources , 3-95
3.7.3 Other Sources 3-96
3.7.4 Pollution Prevention - 3-96
4. REMOVAL OF TOXIC POLLUTANTS BY SECONDARY TREATMENT 4-1
4.1 SECONDARY WASTEWATER TREATMENT PLANTS.... i '..-....., 4-3
4.2 DSS POLLUTANT REMOVALS DATA 4-7
4.3 EVALUATION OF POLLUTANT REMOVAL EFFICIENCY DATA 4-8
VI
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TABLE OF CONTENTS (continued) .
Section Pa ye
4.3.1 Derivation of a Project Definition for Secondary Treatment... 4-14
4.3.2 Pollutant Removals Efficiency Data Bases.............. 4-15
4.3.3 Analysis of Secondary Treatment Plant Pollutant Removals
Data.. ; I; ....™...... 4-18
4.4 FINDINGS:.,...... ',. 4-35
5. CAPABILITY OF POTWs To REVISE PRETREATMENT STANDARDS 5-1
5.1 OVERVIEW OF PRETREATMENT STANDARDS .. 5-2
5.1.1 Prohibited Discharge Standards;......;............... ... 5-3
5.1.2 Local Limits..... —,. 5-3
5.1.3 Categorical Standards 5-4
5.2 POTW REVISIONS TO PRETREATMENT STANDARDS....... ......... 5-11
5.2.1 Removal Credits Development and Implementation. .5-11
5.2.2 Local Limits Development and Implementation 5-16
5.3 ENVIRONMENTAL AND TECHNICAL CRITERIA...... 5-23
5.3.1 Water Quality:. ;.....:.....'.-. 5-23
5.3.2 Standards for the Use and Disposal of Sewage Sludge.... 5-29
;5.3.3 Air Quality,.. ...:....... 5-33
5.3.4 POTW Protection and Worker Health and Safety.... , 5-34
5.4 DATA SOURCES AND METHODS 5-35
5.4.1 Memodology Utilized to Assess POTW Capability 5-35
.5.4.2 Data to Assess Capability to Meet Technical Objectives .....5-36
'- 5.4.3 Data to Assess Capability to Perform Required Tasks 5-42
5.5 EVALUATION OF POTW CAPABILITY TO DEVELOP REMOVAL ,
CREDITS .'.. .......: .;....... _..,....,.............,......... 5-44
5.5.1 History of the RemovalCredit Program , 5-44
5.5.2 Capability to Develop Removal Credits.... 5-49
Vll
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TABLE OF CONTENTS (continued)
Section Page
5.6 EVALUATION OF POTW CAPABILITY TO DEVELOP AND
IMPLEMENT LOCAL LIMITS ...:.... 5-57
5.6.1 History of the Development and Implementation of
Local Limits . 5-57
5.6.2 Capability to Develop Local Limits . 5-60
5.7 STATUS OF POTW EFFORTS TO DEVELOP REMOVAL CREDITS
AND LOCAL LIMITS . , '. 5-71
5.7.1 " Removal Credit Status.... •. , 5-71
5.7.2 Status of Local Limits . 5-71
5.7.3' Case Studies 5-74
5.8 FINDINGS . .. '... 5-78
5.8.1 Local Limit Findings ...., , 5-78
5.8.2 Removal Credit Findings....... .......... 5-79
6. ADEQUACY OF DATA ON TEE ENVIRONMENTAL EFFECTS OF TOXIC
DISCHARGES FROM POtws.. '. 6-1
6.1 GENERAL FATE AND EFFECTS OF TOXIC POLLUTANTS
DISCHARGED TO POTWS 6-2
6.1.1 Fate of Toxic Pollutants Discharged to POTWs 6-2
6.1.2 Toxic Effects of Commonly Released Toxic Pollutants 6-10
6.2 SURFACE-WATER EFFECTS.. 6-16
6.2.1 Sources and Adequacy of Data 6-16
6.2.2 Methodologies for Determining Impacts.....; 6-20
6.2.3 Results ..."......,.- • —• • 6-24
6.3 GROUND-WATER EFFECTS 6-35
6.3.1 Sources and Adequacy of Data 6-35
6.3.2 Methodologies for Determining Impacts 6-36
6.3.3 Results.......: ; 6-37
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TABLE OF CONTENTS (continued)
Section Page
6.4 AIR EFFECTS ... :. ......... 6-38
6.4.1 Sources and Adequacy of Data........ .„ 6-38
6.4.2 Methodologies for Determining Impacts 6-41
6.4.3 Results ............ , ; 6-41
6.5 FINDINGS............ !...... 6-44
7. EFFECTIVENESS OF THE NATIONAL PRETREATMENT PROGRAM ...™.. 7-1
7.1 ASSESSMENT OF THE SCOPE OF THE NATIONAL PRETREATMENT
PROGRAM..... ...:....,.......,..'...,..:..• .................... "7-1
7.1.1 POTWs Covered by Pretreatment Programs.. '.. 7-1
7.1.2 Industries and Pollutants Regulated by the National
Pretreatment Program......... , 7-7
7.2 PROGRAM IMPLEMENTATION.. .: 7-16
7.2.1 POTW Pretireatment Programs .........-,...'...... 7-16
7.2.2 States as Control Authorities. .:....., 7-23
7.2.3 EPA as the Control Authority... . 7-24
7.2.4 EPA and State Oversight Activities '. ....;..... 7-26
7.3 PROGRAM PERFORMANCE 7-28
7.3.1 Water Quality .;. 7-29
7.3.2 . Sewage Sludge... ;......-. 7-46
7.3.3 Worker Health and Safety............ 7-54
7.3.4 Air .7-54
7.4 FINDINGS.. ". .,....„....„ 7-55
8. EVALUATION OF ALTERNATIVE REGULATORY STRATEGIES 8-1
. 8.1 ALTERNATIVE DEVELOPMENT AND SELECTION 8-3
•' • • t !
8.1.1 Identification of Potential Alternatives : 8-3
8.1.2 Screening and Selection of Alternatives in Light of Report
Findings ', 8-4
8.1.3 Methods and Data Sources for Alternatives Evaluation..... 8-11
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TABLE OF CONTENTS (continued) ,
Section Page
8.2 DETAILED CHARACTERIZATIONS OF REGULATORY ALTERNATIVES .... 8-11
8.2.1 Alternative 1: Enhance National Pretreatment Standards 8-11
8.2.2 Alternative 2: Improve/Restrict Site-Specific Toxic
Discharge Standards 8-13
8.2.3 Alternatives: Enhance Environmental Controls on POTWs 8-15
8.2.4 Alternative 4: Expand Pretreatment Monitoring
Requirements ; 8-17
8.2.5 Alternative 5: Shift Administrative Responsibilities in the
National Pretreatment Program......... 8-19
8.3 EVALUATION OF STATUTORY/REGULATORY ALTERNATIVES
FOR THE PRETREATMENT PROGRAM 8-19
8.3.1 Evaluation of Alternative 1: Enhance National Pretreatment
Standards 8-32
8.3.2 Evaluation of Alternative 2: Improve/Restrict Site-Specific
Standards '. 8-37
8.3.3 Evaluation of Alternative 3: Enhance Environmental
Controls at POTWs....... ..: 8-39
8.3.4 Evaluation of Alternative 4: Expand Pretreatment Monitoring
Requirements . 8-41
8.3.5 Evaluation of Alternative 5: Shift Administrative Burdens/
Responsibilities in the National Pretreatment Program.. 8-43
9. FINDINGS AND RECOMMENDATIONS 9-1
9.1 FINDINGS ..„ 9-1
9.1.1 Sources and Amounts of Pollutants Discharged to POTWs 9-1
9.1.2 Extent of Removal of Toxic Pollutants at Secondary
Treatment Plants 9-3
9.1.3 POTW Capability to Revise Pretreatment Standards 9-4
9.1.4 Adequacy of Data on the Environmental Effects of Toxic
Discharges From POTWs........... 9-6
9.1.5 Effectiveness of the National Pretreatment Program 9-7
9.1.6 Alternative Regulatory Strategies for Pretreatment 9-9
9.2 RECOMMENDATIONS 9-9
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LIST OF FIGURES
Figure . Page
1-1 Status of State NPDES and Pretreatment Program Approvals,
November 1990 . . 1-7
1-2 Approved Local Pretreatment Programs, April 1990 1-9
1-3 Numbers of POTW Pretreatmerit Programs Approved by Selected Dates,
1982-1990........,.:.. „.. ......... ;.... 1-10
2-1 Example of Linkage of Data Sources for Chapter 6 Water Quality
Exceedance Analysis 2-19
3-1 Priority Pollutants ..... . 3-4
4-1 Simplified Flow Diagram of a Secondary Wastewater Treatment Plant 4-4
4-2 .Minimum, Average, and Maximum Daily Percent Removal Efficiencies from
,47-POTW Data Base (across all POTWs) .........;.;.„ 4-29
4-3 In-Plant Removal Efficiency Distribution for Copper from One POTW in the
47-POTW Data Base .. .. 4-30
4-4 In-Plant Removal Efficiency Distribution for Zinc from One POTW in the
47-POTW Data Base.......... . ....,.„..,...., 4-30
4-5 In-Plant Removal Efficiency Distribution for Chromium from One POTW in the
47-POTW Data Base ........... , . .„„.. 4-31
4-6 In-Plant Removal Efficiency Distribution for Nickel from One POTW in the
47-POTW Data Base.. ....; :...„ 4-31
4-7 In-Plant Removal Efficiency Distribution for Lead from One POTW in the
47-POTW Data Base ..„...„ ...... 4-32
5-1 Equations for Deriving Allowable POTW Influent Loadings „
From In-Plant Criteria ....„.-.:...;.., 5-20
5-2 Evaluation Approach to Determining POTW Capability to Revise/Develop
Pretreatment Standards „ ....;...„ 5-37
5-3 Outline of the Removal Credits Development Process 5-40
5-4 Outiine of the Local Limits Development Process , 5-41
5-5 Data Sources Used to Determine POTW Capability to Revise
Pretreatment Requirements 5-43,
5-6 Time Line of Removal Credits Milestones ,......„. ,.... 5-48
«
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LIST OF FIGURES (CONTINUED)
Pa ye
5-7 Time Line of Local Limits Milestones..... . 5-61
5-8 Numbers of Pollutants Monitored, Detected,-and Regulated at
Case Study POTWs, 1989 5-77
6-1 Points of Release of Toxic Pollutants From POTWs for Major
Receiving Environments i 6-3
6-2 Percent of Environmental Releases From POTWs Entering
Air, Water, or Sludge.; 6-7
7-1 Total Annual Metals Loading (in influent) to the Field's Point Wastewater
Treatment Facility, Narragansett Bay Commission, RI (total pounds per
year) ; 7-31
7-2 Metals Reductions by an Industry in Erie, PA 7-34
7-3 Historical Changes in Municipal Metal Loadings in the San Francisco'
Bay System 1975-1985 7-39
7-4 Reductions in Cumulative Influent and Effluent Loadings of Six Metals in
Hampton Roads Sanitation District's Wastewater Treatment Plants 7-40
7-5 Influent and Effluent Reductions in Lead and Cadmium at Hampton Roads
Sanitation District's Wastewater Treatment Plants 7-41
7-6 Influent and Effluent Reductions in Copper and Zinc at Hampton Roads
Sanitary District's Wastewater Treatment Plants 7-42
7-7 Metals Loadings in Sludge at Pocatello POTW..... 7-52
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LIST OF TABLES
Table
1-1 Distribution of POTWs by Design Flow Rates : . ... 1-12
1-2 Types of Treatment Provided by Pretreatment and Other POTWs 1-13
1 -3 Types of Receiving Waters to Which POTWs Discharge 1-14
1-4 Status of Categorical Standards .. 1-16
2-1 Data Framework for Section 519 Study.. -. 2-5
. '
2-2 National Data Sources—Ongoing Collection , 2-6
2-3 National Data Sources—One-Time Collection........ 2-9
2-4 -Major Data Sources Compiled Specifically for This Study.... 2-16
2-5 Other Data Sources ....;... 2-17
2-6 Uses of Data Sources...... 2-20
2-7 General Characteristics of Case Study Cities 2-22
3-1 Numbers of Categorical and Significant Industrial Users... 3-8
3-2 Percent Industrial Flow by POTW Average Daily Flow Rate...... 3-14
3-3 Distribution of POTW Control Authorities, POTWs, and Industrial Users by
Average Daily Flow » * 3-17
3-4 Industrial Categories as Profiled in the EPA Domestic Sewage Study 3-18
3-5 Summary of Total Metals/Cyanide and Organics Discharged to POTWs
From Consent Decree Industrial Categories 3-22
* -. . , -
3-6 Top 20 Toxic Priority Pollutants With the Highest Loadings for the
Consent Decree Industrial Categories Within the Scope of the NRDC
Consent Decree ...„ 3-25
3-7 Summary of the Number of Toxic Pollutants Associated With Direct
and Indirect Discharges From Non-Consent Decree Industrial Categories 3-28
3-8 Summary of Data Reported in TRIS by Industrial Category for 1988 3-30
3-9 Summary of Toxic Pollutants Reported as Being Released by 10 or More
Facilities to POTWs in TRIS for 1988... '. 3-33
3-10 Summary of Toxic Pound Equivalents for the Priority Pollutants Reported
As Being Released to POTWs in TRIS for 1988 3-37
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LIST OF TABLES (CONTINUED)
Table
3-11 Relative Ranking of Pollutants Reported as Directed to POTWs in TRIS 3-38
3-12 Comparison of Quantities of DSS Toxic Pollutants Released to POTWs as
Reported in TRIS and DSS • 3-40
3-13 Summary of the Number of Pollutants Found Above Detection Limits by
EPA for Industrial Categories Studied Under Section 304(m) of the Clean
Water Act. : .... 1................... 3-44
3-14 Summary of North Carolina Industrial Dischargers That Report Effluent
Monitoring Results to the State, . ... »• 3-48
3-15 Overall Average Inorganic Domestic Pollutant Levels...... , 3-52
3-16 Overall Average Organic Domestic Pollutant Levels ; ......... 3-52
3-17 Hazardous Constituents of Common Household Commodities 3-54
3-18 Number of Household Hazardous Waste Collection Programs in 1989 3-59
3-19 Contaminants Required to be Regulated Under the 1986 SDWA
Amendments and Existing MCLs . 3-61
3-20 Estimates of POTW Removal Efficiencies Needed to Remove Toxic
Pollutants Discharged at Typical Domestic Concentrations 3-64
3-21 Summary of Local Limit Submissions for 25 POTWs in Region VI 3-66
3-22 Pretreatment Programs with Combined Sewer Overflows (CSOs)..... 3-68
3-23 Frequency of Detection of Priority Pollutants In Urban Runoff During
the Nationwide Urban Runoff Program ...» • 3-71
„ % • " ''' ,, , ' - - . , , '•
3-24 Summary of Pollutants Detected in Septage Hauler Wastes ._. 3-75
3-25 Overview of Industries Discharging to Case Study POTWs.... 3-84
3-26 Sources of Toxic Pollutants Discharged to Case Study POTWs... 3-86
. . " \
3-27 Summary of Case Study Information in the EPA Pollution Prevention
Information Clearinghouse.. '..., • 3-89
•t ,
4-1 Comparison of Estimated DSS Percent Removals With Those Obtained
Using 40-POTW Study Data , ...., - ••• 4-9
4-2 Summary Table of Estimated Fraction Removed: Stripped, Partitioned, and
Biodegraded for Pollutants With Partitioning Rates Available 4-12
4-3 Pollutants Considered in DSS, the MIS A Study, and the 47-POTW Data Base 4-19
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LIST OF TABLES (CONTINUED)
Table Page
4-4 Pollutant Removal Efficiencies Reported in the 47-POTW Data Base..... 4-22
4-5 Descriptive Statistics for Average POTW Removal Efficiencies
in the 47-POTW Data Base..: ; „.... . ...;..„ 4-28
5-1 Industrial Categories with Pretreatment Standards for Existing Sources
' (PSES) and Pretreatment Standards for New Sources (PSNS)......... .. 5-5
5-2 Consent Decree Industrial Categories With Categorical Pretreatment
Standards............ ,.. ,.......„. 5-6
.5-3 Nonconsent Decree Industrial Categories With Categorical Pretreatment
Standards ...... 5-9
5-4 Number of States and Territories With Water Quality Standards for
Priority Pollutants , ...,. 5-26
5-5 Number of Limits for Toxic Pollutants in NPDES Permits Issued to
Pretreatment POTWs........... ..„ „ 5.30
5-6 Technical Objectives and Technical Tasks Involved in the Development
of Removal Credits and Local Limits..... . ...... 5-38
5-7 Removal Credits Applications.... 5-50
5-8 Pollutants for Which POTWs Requested Removal Credits.....: 5-5;l
5-9 Pollutants for Which Selected POTWs Have Established Local Limits. 5-63
5-10 Types of Local Limits Being Implemented by POTWs ....: 5-72
5-11 Number of Toxic Pollutants Detected and Regulated by Local Limits and
Environmental Criteria....;. 5.75
i
5-12 Sampling Frequency by Case Study POTWs, 1989 5-76
5-13 Number of Samples Used by Case Study POTWs to Develop Local Limit....... 5-76
6-1 Percentages of Selected Pollutants in POTW Influents Released to the
Environment in Surface Waters, Air, and Sludge 6-8
6^2 Toxic Effects of Common Pollutants in Aquatic and Terrestrial Environments. 6-12
6-3 . Water Quality Criteria for Compounds With Acute or Chronic Freshwater
Criteria 1 ; ..-.,...;.-.-. ;....... 6-17
. 6-4 Amount of Assessed Surface Waters Not Fully Meeting Use Designations
in 1988 Because of the Cause Listed (from all sources)........! 6-25
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LIST OF TABLES (CONTINUED)
Table Page
6-5 Amount of Assessed Surface Waters Not Fully Meeting Use Designations
in 1988 Because of the Source Listed 6-27
6-6' Number of POTWs on the 304(1) Short-List of Facilities Contributing to
Water Quality Standards Exceedances for Toxic Pollutants 6-28
6-7 Number of POTWs Included in the Water Quality Criterion Exceedance
Analysis . r..... 6 29
6-8 Number of Water-Quality Criterion Exceedances Expected to Be Caused
by Pretreatment POTW Discharges at Low Flow (7Q10) 6-30
6-9 Criterion Exceedances Indicated by Toxicity Test Results on POTW
Effluents 6-34,
6-10 Numbers of POTWs Using Specific Sludge Disposal Practice as Primary
Sludge Disposal Practice and Amounts of Sludge Disposed of Using
Each Practice 6-36
.6-11 Mean Concentration of Selected Toxic Pollutants in Sewage Sludge from
the National Sewage Sludge Survey (1988 data) ... 6-39
6-12 Relative Emissions of Pollutants Per Unit of Incinerated Sludge and
Relative Cancer Risks Posed by Emission 6-42
6-13 Health Incidents Attributed to POTW Air Emissions.. ...........; 6-45
7-1 Industrial Discharges to Pretreatment and Other POTWs, ; 7-4
7-2 Pretreatment Status of POTWs Receiving the Largest Amounts of Toxic
Chemicals, 1988 , .. 7-5
7-3 Priority Pollutants Discharged and Regulated at POTWs Covered by the
National Pretreatment Program 7-9
7-4 Status of POTW Program Implementation 7-18
7-5 Specific Program Deficiencies Identified in Audits 7-20
7-6 Guidance Materials Applicable to the Pretreatment Program 7-22
7-7 State and EPA Activities as Control Authorities for Nonpretreatment
POTWS 7-25
7-8 Reported Reductions in Concentrations or Loadings of Metals and
Cyanide in Influent and Effluent '. 7-35
7-9 N.umber and Percent of Reporting POTWs. with Instream Concentrations
Exceeding National Water Quality Criteria 7-44
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LIST OF TABLES (CONTINUED)
Table Page
7-10 Summary of Ambient Monitoring Data Analysis: Pollutant Trends... 7-45
7-11 Changes in Mean Pollutant Concentrations Before and After
Pretreatment in the Sludge of 24 Wisconsin Treatment Plants (since 1977).... 7-48
7-12 Examples of POTWs Demonstrating Reductions in Loadings of Metals
in Sludge... ..„ 7-49
8-1 Goals of the Clean Water Act.... 4 .,....„ 8-2
8-2 Initial Suggestions for Improving Pretreatment Program—Regulatory/
Statutory and Nonregulatory Alternatives..!..... .. 8-5
8-3 Report to Congress Findings and Alternatives.. 8-6
8-4 Overview of Regulatory Alternatives and Options 8-9
8-5 Qualitative Assessment of Pretreatment Alternatives...... 8-20
8-6 Quantitative Assessment of Pretreatment Alternatives..... „., 8-26
XVll
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EXECUTIVE SUMMARY
This report presents the results of a study on the discharge of toxic pollutants to and
from publicly owned treatment works (POTWs) performed by the U.S. Environmental
Protection Agency (EPA) in response to Section 519 of the Water Quality Act (WQA) of
1987. -
Specifically, Section 519 of the WQA directed EPA to study the following:
• The adequacy of data on environmental impacts of toxic industrial pollutants
discharged from POTWs
• The extent to which secondary treatment at POTWs removes toxic pollutants
• The capability of POTWs to revise pretreatment requirements under Section
307(b)(l) of the Federal Water Pollution Control Act (FWPCA)
• Possible alternative regulatory strategies for protecting the operations of POTWs
from industrial discharges and the extent to which each strategy is expected to
achieve the goals of this Act - '
• For each alternative regulatory strategy, the extent to which removal of toxic
pollutants by .POTWs results in contamination of sewage sludge and the extent to
which pretreatment requirements may prevent sludge contamination or improve the
ability of POTWs to comply with sewage sludge criteria developed under Section 405
of the FWPCA
• For each alternative strategy, the adequacy of Federal, State, and local resources to
establish, implement, and enforce multiple pretreatment limits for toxic pollutants.
Section 519 further directed EPA to submit a report on the results of the study along
with recommendations for improving the effectiveness of pretreatment requirements. The
Office of Wastewatef Enforcement and Compliance, developed this report, and advice and
comments were provided by a work group consisting of EPA Regions and States and
representatives of EPA program offices.
, PURPOSE OF REPORT TO CONGRESS
This report constitutes a comprehensive evaluation of the National Pretreatment
Program, with particular emphasis on the study topics listed in Section 519. The National
Pretreatment Program was established by Section 307 of the Clean Water Act (CWA) and is
implemented through the General Pretreatment Regulations (40 CFR Part 403) and
categorical pretreatment standards (40 CFR Parts 405-471). It involves municipalities,
States, and the Federal Government in efforts to control pollutants from nondomestic (i.e.,
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industrial and commercial) sources and prevent pass through, interference, and sludge
contamination at POTWs.
Industrial dischargers are required to pretreat their wastewaters prior to discharge to
POTWs in accord with national pretreatment standards (consisting of national prohibited
discharge standards, technology-based categorical standards, and locally established
discharge limitations). In addition, industrial users must meet other obligations, such as
monitoring, reporting, and spill prevention, under the General Pretreatment Regulations. In
most cases, the principal developers and enforcers of pretreatment requirements at the local
level are POTWs, with assistance and oversight provided by States, EPA Regions, and EPA
Headquarters. The National Pretreatment Program extends to more than 200,000
nondomestic sources, of which 30,000 are considered significant industrial users (SIUs), and
to nearly 1,500 approved local pretreatment programs. Approved programs cover over 2,000
wastewater treatment plants, which in turn treat nearly 80 percent of the municipal
wastewater flow nationally.
The purpose of this evaluation is to determine, after the pretreatment program has been
underway for over a decade, how the program can more effectively achieve the goals of the
CWA and minimize the adverse environmental impacts of toxics that may be discharged from
POTWs.
STUDY APPROACH AND ORGANIZATION
The congressional mandate and characteristics of the National Pretreatment Program
influenced the Agency's approach to this study. First, Congress requested a national
assessment of the program. Furthermore, Congress requested information on environmental
impacts from a program that historically has been largely technology-based. Finally, the
National Pretreatment Program has undergone intensive examination several times in its
relatively brief history, enabling the Agency to use the results of previous studies.
EPA has, therefore, designed this Report to Congress to:
• Provide as complete an assessment of the pretreatment program as possible
• Present actual rather than projected results of the program (e.g., through the use of
actual monitoring and compliance data rather than modeling results)
• Use and combine data from various EPA program offices (e.g;, the Toxics Release
Inventory System, NEEDS 1988 Survey File, and the Permit Compliance System)
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• Build upon existing national studies (e.g., the Domestic Sewage Study and the
40-POTW Study)
• Combine performance of the study with ongoing program implementation activities
(e.g., State and local pretreatment program audits)
• Supplement national data with State and local data;
This evaluation of the National Pretreatment Program is organized into nine chapters.
Chapter 1 provides background information on the National Pretreatment Program and its
relationship to other water pollution control programs under the CWA.
Chapter 2 characterizes the data sources and the methodology used by EPA to
complete the report.
Chapter 3 characterizes the sources and discharges of toxic pollutants to POTWs. The
chapter also provides information on pollution prevention activities undertaken within various
types of industries.
Chapter 4 explores the extent to which secondary wastewater treatment plants remove
toxic pollutants. It describes the fate of toxic pollutants within treatment plants,
differentiating bona fide removal (biodegradation) from partitioning to air and sludge, and
characterizes actual secondary treatment plant performance in removing toxic pollutants from
wastewater.
Chapter 5 evaluates the capability of POTWs to revise pretreatment standards through
two mechanisms: removal credits and local limits. The chapter describes the statutory and
regulatory history of the removal credits and local limits programs and discusses the
processes by which POTWs develop, submit, and implement these mechanisms. It also
describes existing Federal, State, and local environmental and technical criteria that influence
the establishment of removal credits and local limits, in addition to summarizing the current
status of POTW development and implementation of removal credits and local limits. Finally,
the chapter addresses the capability of POTWs to obtain removal credits and to develop,
implement, and enforce local limits.
* ' '•'•'•,"•
Chapter 6 examines the adequacy of data on environmental impacts of toxic pollutants
discharged from POTWs and the extent of those impacts, where known. It provides
information on the nature of POTWs' receiving waters and sludge disposal methods. Chapter
i , • ' . ' / -
: . •."'.•-- , ES-3 • ' ' . -•. •
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6 also describes potential environmental effects of POTW discharges and analyzes the extent
to which POTWs comply with various environmental standards and criteria, and it
characterizes the adequacy and limitations of the data with which impacts are assessed.
Chapter 7 evaluates the effectiveness of the existing National Pretreatment Program by
examining the following: whether the program covers the appropriate POTWs, pollutants,
and industries; whether POTWs are effectively implementing the requirements of the
program; and whether the program is effective in preventing or reducing the environmental
impacts of toxic pollutants discharged by POTWs. The chapter examines program
implementation requirements and identifies areas where POTWs have and have not met
specific program requirements. ,
Chapter 8 explores alternative regulatory strategies for enhancing the National
Pretreatment Program. It describes how alternatives were selected and then characterizes
17 supporting regulatory options in terms of their purpose, scope, affected parties,
applicability to' CWA objectives, and impact on sewage sludge quality. Study findings in
support of each alternative are considered. These alternatives are also assessed for their
implementation and compliance costs.
Chapter 9 summarizes report findings and recommends ways to enhance attainment of
the environmental objectives underlying the pretreatment program.
MAJOR FINDINGS AND RECOMMENDATIONS
Sources and Amounts of Pollutants Discharged to POTWs .
• Sources
- Nationwide, more than 15,000 POTWs receive and treat a total of approximately
34 billion gallons per day of domestic, commercial, and industrial wastewater.
— A total of 1,542 POTWs (encompassing 2,128 individual municipal wastewater
treatment plants) are required to have approved local pretreatment programs. As
of March 1990, 1,442 of the 1,542 (94 percent) have approved local programs.
Toxic discharges to another 314 POTWs are regulated by State-run pretreatment
programs, pursuant to 40 CFR 403.10(e), in lieu of local programs. Those POTWs
with approved pretreatment programs and those covered by State-run programs
receive more than 80 percent of the national wastewater flow discharged to
POTWs.
— EPA estimates that 30,000 significant industrial users (SIUs) discharge to
POTWs. This number comprises approximately 11,600 categorical industrial users
(CIUs) and 18,400 noncategorical SIUs.
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- Several hundred thousand other nondomestic users discharge to wastewater
treatment plants across the United States. These facilities include retail and
commercial establishments, as well as industries that do not meet EPA's
definition of significant industrial user.
Sources and Types of Industrial Discharges
- The Domestic Sewage Study, assuming imposition of arid compliance with
categorical Pretreatment Standards for Existing Sources (PSES), identified the
following industrial categories responsible for the highest loadings of 165 metals
and toxic organics to POTWs:
- - Metals: Electroplating and metal finishing; industrial and commercial
laundries; organic chemicals manufacturing; coal, oil, petroleum products and
refining; and pulp and paper mills.
- - Organics: Equipment manufacture and assembly; pharmaceutical manufacture;
organic chemicals manufacturing; coal, oil, petroleum products and refining; and
industrial and commercial laundries.
- Data from the Toxics Release Inventory System regarding releases of more than
300 listed toxic chemicals showed that more than 5,700 industrial facilities
estimated discharges of more than 680 million pounds of toxic pollutants to more
than 1,700 POTWs in 1988. The industrial categories reporting the largest volume
released to POTWs were fertilizer manufacturing; organic chemicals
manufacturing; dye manufacturing and formulating; pulp and paper mills; food and
food by-products processing; and pharmaceutical manufacturing.
- For the 165 pollutants analyzed in the DSS (plus copper and zinc), annual POTW
loadings of toxic pollutants reported in TRIS (159 million pounds) exceed loadings
estimated in the DSS (60 million pounds), although the DSS represented more
facilities discharging to POTWs.
Other Potentially Significant Sources
- Findings for the DSS, TRIS, and EPA's 304(m) plan suggest that commercial and
industrial facilities not yet subject to categorical pretreatment standards may
discharge considerable quantities of toxic pollutants to POTWs. Such facilities
include machinery manufacturing and rebuilding, industrial and commercial
laundries, hazardous; waste treatment facilities, and waste reclaimers.
— Domestic wastewaters may contain considerable amounts of toxic pollutants as a
result of the disposal of household hazardous wastes. In some cases, pollutants
contributed by drinking water supplies and drinking water conveyance systems
may also be significant. Inorganic pollutants .present in domestic wastewater
include metals such as copper, iron, lead, and zinc. Organic compounds may
include pesticides, plasticizers, coal tar compounds, and chlorinated solvents.
- POTWs may also receive significant loadings of toxic pollutants from hauled
wastes, landfill leachate, storm water, or cleanup activities associated with RCRA
corrective actions, Superfund cleanups, and underground storage tanks.
Types of Controls .
- Categorical standards and local limits have brought about significant reductions in
metals loadings and moderate reductions in toxic organics loadings from regulated
industries.
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- - Metals: Toxic metal pollutant loadings from regulated industries are
estimated to be reduced by 95 percent after implementation of PSES. This
reduction results in estimated annual loadings of about 14 million pounds
(6,500 metric tons).
- - Organlcs: Depending on the data source, toxic organic loadings from
regulated industries are estimated to be reduced by approximately 40 to 75
percent after PSES, resulting in annual loadings of .approximately 65
million pounds (30,000 metric tons).
- Planned development of additional categorical standards for such industries as
machinery manufacturing and rebuilding, pharmaceutical manufacturing, industrial
laundries, paint formulating, and hazardous waste treatment is expected to further
reduce loadings of toxic pollutants to POTWs.
- POTWs and industrial users have demonstrated that they understand pollution
prevention and the opportunities it affords to reduce loadings of toxic pollutants.
EPA has found that pollution prevention techniques have been used at 36 of the 47
industrial categories evaluated in this report.
- In 1989, over 600 household hazardous waste collection programs were in place,
many of which were coordinated by POTWs. Further reductions in toxic
pollutants, including commercial and domestic sources, may be necessary to obtain
the reductions needed to achieve desired environmental standards.
>
<
Extent of Removal of Toxic Pollutants at Secondary Treatment Plants
• Fate of Toxic Pollutants
- Toxic pollutants present in the raw sewage entering secondary treatment plants
have several fates. Toxic organic pollutants can biodegrade, partition to sewage
sludge, volatilize, or remain in the discharge to receiving waters. Metals generally
partition to the sewage sludge or remain in the discharge from the POTW.
- The removal of most toxic pollutants from wastewaters is largely incidental to the
treatment of conventional pollutants and should be considered in terms of
partitioning among alternative pathways; toxic pollutants may be shifted from one
medium to another (to the air through volatilization or sludge through adsorption),
as well as destroyed through biodegradation.
• Nature of Pollutant Removals
- Pollutant removal is calculated from the results of sampling the influent and
effluent of a POTW treatment plant.
- EPA's analyses of priority pollutant removals indicate that removal efficiencies for
toxic pollutants vary widely from POTW to POTW.
- Calculation of removals of toxic pollutants at a POTW must consider that removal
involves several pathways and is variable because of changing conditions and
situations at the POTW (e.g., concentration of the pollutant, POTW operational
characteristics, aeration/turbulence, temperature).
- Removal efficiencies do not appropriately represent POTW variability when
expressed as single median values, because of the variability of observed
removals.
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- The broad range of removal efficiencies observed underscores the need for using
POTW-specific data hi making decisions that involve toxic pollutant removals
applicable to individual POTWs.
POTW Capability to Revise Pretreatment Standards
• Status of Removal Credits
- Removal credits are adjustments to categorical pretreatment standards that reflect
the removal of a pollutant by a POTW. A POTW may elect to lessen the
stringency of a categorical standard where it demonstrates it consistently removes
a given pollutant and maintains compliance with its NPDES permit and sludge
requirements. The removal credits program has been suspended since 1986.
Removal credits will remain unavailable until EPA promulgates sludge
requirements pursuant to Section 405 of the CWA.
- When the removal credits program was suspended in 1986, 12 POTWs nationwide
had removal credits approved by EPA, and another 15 had removal credit
applications pending. The approved removal credits covered 16 pollutants and
affected approximately 150 industrial dischargers.
- Future POTW interest in removal credits, once they are available again, is
expected to be low; however, increased regulation of organic pollutants in recently
promulgated and forthcoming guidelines may renew interest in removal credits for
some organic compounds.
• Assessment of POTW Capability: Removal Credits
- POTWs possess adequate resources and technical expertise to perform the tasks
inherent in revising pretreatment standards through removal credits (e.g.,
monitoring and calculation of revised standards).
- Most pollutants for which removal credits were granted (or for which applications
were filed) are metals that do not biodegrade in municipal treatment systems and
that are partitioned instead to sludge.
• Status of Local Limits .
- Analysis of local limits at 200 POTWs found that 90 percent of POTWs have
adopted local limits for one or more toxic pollutants and that more than 70 percent
have adopted local limits for the 10 pollutants listed in EPA guidance as being of
highest concern. A much smaller percentage, however, has adopted local limits
using a headworks loading or other technical basis. POTWs surveyed by the
General Accounting Office were found to impose local limits for an average of 14
toxic pollutants.
- POTWs regulate many more pollutants in their local limits than they are limited for
in their National Pollutant Discharge Elimination System (NPDES) permits.
According to EPA's Permit Compliance System, 32 percent of the NPDES permits
for pretreatment POTWs issued in 1989 contained limits for one or more toxic
pollutants.
• Assessment of POTW Capability: Local Limits
- POTWS are generally capable of developing and implementing local limits.
Weaknesses observed include the following:
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- - In developing local limits, POTWs generally lack site-specific data necessary
to calculate treatment plant removals. The current practice of using literature
POTW removal data to develop local limits may not accurately reflect
treatment plant performance and may result in exceedances of environmental or
technical criteria.
- - POTWs often rely on literature data to predict pollutant concentrations that
may result in unit process inhibition. These literature inhibition data are based
on a limited sample size and may not accurately characterize site-specific
conditions. Additionally, these data are available for only a few pollutants and
treatment processes.
- - The application of local limits to categorical industries often involves
comparisons with the categorical standards to determine which of the limits
(local or categorical) are more stringent. Although EPA has provided guidance
to address this issue, POTWs continue to have difficulty applying the most
stringent standard.
- POTWs often lack sufficient environmental standards, criteria, or permit conditions
to develop technically based limits or judge the appropriateness of existing local
limits. The NPDES permits for two-thirds of the pretreatment POTWs nationwide
do not contain limits for any toxic pollutants. Of those that do, only a few
pollutants are generally limited. In addition, national sludge disposal standards
are not yet in place, and most States do not have comprehensive sludge standards.
POTWs, therefore, are often without specific environmental criteria and standards
upon which local limits are to be based.
Adequacy of Data on the Environmental Effects of Toxic Discharges From POTWs
• Types of Effects and Pathways
- Discharges of toxic pollutants from POTWs can impair the quality of receiving
environments, including surface water, ground water, and air. In addition, the
health and safety of workers at POTWs may be adversely affected.
- Toxic effects vary by pollutant, as well as by receiving medium. Principal effects of
concern are lethality, carcinogenicity (causing cancer), teratogenicity (causing
developmental abnormalities), or mutagenicity (causing genetic abnormalities).
Some compounds discharged from POTWs (PCBs and arsenic) exhibit all of these
deleterious effects. Several metals are lethal, teratogenic, and mutagenic but do
not cause cancer. . .
• Extent of Environmental Criteria
- The lack of comprehensive criteria for all pollutants discharged to and from POTWs
inhibits estimation of the environmental effects of POTW discharges.
- In addition, the POTWs, States, and EPA do not collect or maintain data that are
comprehensive enough to characterize municipal wastestreams or their impacts in
receiving environments adequately. Data on POTWs' effluents and their impacts
are most comprehensive for discharges to surface water.
• Surface-Water Impacts
- Eighty percent of POTWs covered by pretreatment programs discharge treated
effluent to rivers and streams, 4 percent to lakes, 7 percent to oceans, and 9
percent to other environments, including land, estuaries, and reservoirs.
i . . . .
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- Under the 304(1) program, 254 POTWs (171 pretreatment POTWs) are among the
888 facilities contributing toxic pollutants to stream segments not attaining water
quality standards.
• Ground-Water Impacts
— The most significant potential cause of ground-water contamination by POTWs is
disposal of sewage sludge, although empirically this has rarely been a problem.
Forty-two percent of all municipal sewage sludge is beneficially used in land
application, 22 percent disposed of in landfills, 14 percent by incineration, 6 percent
through distribution and marketing, 5 percent by ocean disposal, and 2 percent by
other practices. Roughly three-quarters of sludge is used or disposed of in land-
based practices.
— Pollutants under consideration for regulation in EPA's proposed Part 503
regulations for sludge use and disposal were detected at high frequency in the
National Sewage Sludge Survey (NSSS).. Mean concentrations of certain toxic
metals (arsenic, cadmium, copper, lead, molybdenum, nickel, and zinc) found in
sludge in the NSSS suggest that some POTWs may be precluded from certain
beneficial use or disposal practices unless they can reduce loadings through
additional pretreatment.
• Air/Worker Health and Safety Impacts
— Little is known about the extent and effects of air emissions from POTWs. The
DSS estimated that 0.1 percent of the mass of national emissions of volatile
organic compounds may come from POTWs. Twenty-seven POTWs nationally
are each reported to emit over 100 tons per year of Clean Air Act criteria
pollutants.
Effectiveness of the National Pretreatment Program
• Program Scope
- EPA Regions and States have successfully identified those POTWs whose receipt
of industrial discharges makes pretreatment a necessity. The POTWs with
approved programs, or covered by State-run pretreatment programSj receive more
than 80 percent of the national wastewater flow discharged to POTWs.
- Virtually all the POTWs reported in TRIS to be receiving more than 1 million
pounds of toxic chemicals are covered by programs. Evaluation of various data
sources (e.g., TRIS, NEEDS, 304[1]) may enable EPA to target additional
POTWs for development of local programs. '
« Implementation Status
- Measurements of the level of implementation of local programs indicate that local
implementation is well underway. Ninety-four percent (totaling 1,442) of required
local pretreatment programs have been approved. Twenty-seven States have
approved State pretreatment programs. Specific programmatic implementation
issues will require more attention, such as the need for POTWs to develop
technically based, local limits and to adequately enforce all pretreatment standards
and requirements.
- PCS indicates that 84 percent of SIUs have been issued control mechanisms, and
90 percent of SIUs have been inspected under local programs.
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— EPA Regions and States have performed extensive oversight of local pretreatment
programs, having performed more than 3,600 audits and inspections at 1,328
POTWs in the last 5 years.
— One of the pretreatment program's key strengths is implementation at the local
level, which provides the flexibility necessary to respond to site-specific
conditions. In general, locally implemented programs have been found to regulate
more noncategorical industries than State-run programs. In contrast to State-run
programs, local programs have developed and implemented site-specific local
limits to prevent pass through and interference and have conducted more frequent
monitoring of industries to assess compliance.
- The decentralized, local approach has, however, resulted in instances of
incomplete or inconsistent implementation of local pretreatment programs. As
many as 40 percent of the approved local pretreatment programs need to improve
at least one key area of implementation (e.g., issuance of industrial user control
mechanisms, local limits development, enforcement).
• Environmental Results
— The lack of comprehensive environmental data makes it difficult to evaluate the
program's effectiveness in achieving the goals of the Act. However, evidence from
various data sources suggests that the pretreatment program has resulted in
significant reductions in the discharge of toxic pollutants to POTWs and from
POTWs to the environment. ,
— Many POTWs report significant declines in concentrations and loadings of toxic
pollutants in influent, effluent, and sludge associated with implementation of
pretreatment programs. These decreases have reduced operational problems and
improved the quality of receiving waters and sludges.
Alternative Regulatory Strategies for Pretreatment
• The overall regulatory framework for control of toxic discharges to POTWs appears to
provide suitable mechanisms to address environmental concerns and achieve the
goals of the Act.
1 .' -
RECOMMENDATIONS
From the major findings in this Report to Congress, EPA recommends the following
approaches, none of which require statutory change, to further reduce the environmental
impacts associated with toxic discharges to and from POTWs:
• Continue to promulgate national categorical pretreatment standards and stress the
adoption of cost-effective pollution prevention and domestic wastewater controls
wherever feasible.
• Improve local pretreatment standards to further reduce toxic loadings and to ensure
the integrity of POTW collection systems.
• Improve the scientific basis of pretreatment controls, and provide better benchmarks
for pretreatment program performance, by establishing comprehensive standards and
criteria for all media affected by POTW discharges.
i ' : ,
ES-10
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.Aspects of these broad recommendations are explained more fully below. It should be
noted that EPA is currently undertaking many regulatory development arid program
implementation activities envisioned by these recommendations. These recommendations do
not comprise entirely new initiatives, but are intended to complement ongoing water pollution
control efforts by municipalities, States, and EPA. ~
. • . ' • /
Recommendation One: Enhance National Categorical Pretreatment Standards
• Continue to develop new and revised categorical standards in accordance with EPA's
plan developed under 304(m), and continue to review new pollutants, particularly
those nonpriority pollutants now known to pose significant environmental risks, for
inclusion in categorical standards. Where final standards are not necessary on a
national basis, issue guidance to POTWs on problem pollutants and control options.
• Continue to consider cost-effective pollution prevention techniques as the basis for
categorical standards where such techniques offer the best available technology
economically achievable (BAT). \
• Reexamine the removal credit requirements of the General Pretreatment Regulations
(Section '403.7) in light of the findings of this report. Further topics for examination
might include the definition of consistent removal, monitoring requirements, types of
compounds for which removal credits are and are not available, the use of data from
similar POTWs, and specific conditions for inclusion in the NPDES permit once
removal credits are approved.
Recommendation Two: Improve Local fretreatment Standards
• Promote opportunities for use of cost-effective pollution prevention tools in industrial
user permitting, local limits development, spill control, and inspections to reduce
nondomestic loadings of toxic pollutants. Encourage market forces and industrial
user input into the process of developing arid allocating POTW local limits.
• Promote domestic hazardous waste programs and other opportunities to reduce
discharges of pollutants from domestic sources.
• Consider revising the local limits requirements in the General Pretreatment
Regulations (Section 403.5) to address methods for determining pollutants of
concern, use of actual monitoring data instead of default or literature values, the basis
of limits, and other issues.
• Consider developing additional local limits guidance for high-risk rionconservative
organic pollutants (e.g., volatile organic compounds).
• Assess the degree to which corrosion control programs and pipe replacement
• programs completed in response to Safe Drinking Water Act requirements may
reduce concentrations of pollutants in municipal wastewaters.
ES-11
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Recommendation Three: Improve Scientific Basis of Pretreatment Controls
• Continue to emphasize with EPA Regions and States the need for water quality-
based NPDES permits for pretreatment POTWs.
• Continue to train permit writers in methods for incorporating water quality-based
limits and sludge requirements in NPDES permits.
• Target pretreatment POTWs for additional monitoring and reporting, in order to
ascertain the need for additional toxics control, based on data showing actual or
reasonable potential for problems. Target additional POTWs for development of local
pretreatment programs based on these same data sources.
• Establish measures for assessing the environmental effectiveness (e.g., improved
water quality and sludge quality) of local pretreatment programs. Incorporate these
measures into ongoing implementation activities (such as audits, PCIs, or POTW
annual reports).
• Continue to develop water quality and sludge quality standards.
' • Issue guidance to States emphasizing the need to develop water quality standards
and wasteload allocations for toxics of concern. Provide technical assistance as
necessary.
• Continue aggressive enforcement of pretreatment standards and requirements at the
local, State, and Federal levels.
ES-12
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1. BACKGROUND AND INTRODUCTION
This Report to Congress responds to Section 519 of the Water Quality Act (WQA) of
1987. The WQA/which amended the Clean Water Act (CWA) of 1977, required the U.S.
Environmental Protection Agency (EPA) to evaluate several issues related to the National
Pretreatment Program. Specifically, Section 519 directed EPA to study:
• The adequacy of data on environmental impacts of t toxic industrial pollutants
discharged from publicly owned treatment works (POTWs)
• The extent to which secondary treatment at POTWs removes toxic pollutants
• The capability of POTWs to revise pretreatment requirements under Section
307(b)(l) of the Federal Water Pollution Control Act
• Alternative regulatory strategies for protecting the operations of POTWs from
industrial discharges, and the extent to which each strategy is expected to achieve
the goals of the WQA
• For each alternative strategy, the extent to which removal of toxic pollutants by
POTWs results in contamination of sewage sludge, and the extent to which
pretreatment requirements may prevent sludge contamination or improve the ability
of POTWs to comply with sewage sludge criteria
• For each "alternative strategy, the adequacy of Federal, State, and local resources to
establish, implement, and enforce multiple pretreatment limits for toxic pollutants.
Section 519 also directed EPA to submit a Report to Congress on the results of the
study and to recommend ways to improve the effectiveness of .pretreatment requirements.
This report addresses this mandate. The Office of Water Enforcement and Permits (OWEP)
prepared the report with the help of EPA Regions, selected States, and other EPA program
offices.
1.1 THE NATIONAL PRETREATMENT PROGRAM
This Report to Congress constitutes an assessment of the National Pretreatment
.Program. The pretreatment program, which is part of EPA's water pollution control program
under the CWA, is a joint regulatory effort by Federal, State, and local authorities that
requires the control of nondomestic (i.e., industrial and commercial) sources of toxic
• S .!
pollutants discharged to POTWs. .Pretreatment minimizes the likelihood of treatment plant
upsets and reduces,the level of toxic pollutants in wastewater discharges from the POTW
and in the sludge resulting from municipal wastewater treatment.
1-1
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1.1.1 Controls on POTWs Under the Clean Water Act
The National Pollutant Discharge Elimination System (NPDES) permit program under
' Section 402 of the CWA protects surface waters of the United States from pollution by
wastewater discharges, including discharges from POTWs. NPDES permits control more
than 64,000 discharges to surface waters. Of these, 49,000 are industrial sources (3,000
major industrial sources and 46,000 minor industrial sources, mainly manufacturing and
commercial facilities). The remaining 15,000 sources are POTWs.
Wastewater from POTWs consists of domestic sewage and industrial and commercial
wastes that are discharged indirectly to surface waters via sewers by industrial users of the
POTWs. There are hundreds of thousands of industrial users in the United States,
Approximately 30,000 industrial users meet EPA's definition of "significant industrial user"
(defined in Subsection 1.1.6). "Pretreatment" is the removal by industrial users of pollutants
from their wastestreams before they discharge the wastestreams to POTWs. Pretreatment
ensures the protection of surface waters from the effluent discharged from POTWs and also
protects POTWs from interference with plant operations that may be caused by certain
discharges from industrial users.
Each POTW that discharges directly to surface waters must apply for and obtain an
NPDES permit. These permits are issued either by EPA or a State (where the State is
authorized to administer its own NPDES program). EPA or State permit writers examine the
volume and quality of municipal effluent and then develop pollutant-specific numeric limits and
other requirements for the POTWs permit. The NPDES permit also requires other actions,
such as submitting discharge monitoring reports, operating a pretreatment program, or
• meeting schedules for complying with permit conditions. NPDES permits have a maximum
duration of 5 years under current law.
The CWA originally emphasized the control of conventional pollutants discharged by
POTWs. Conventional pollutants are biochemical oxygen demand (BOD), total suspended
• solids, fecal coliform, pH, and oil and grease. Section'301 of the CWA required POTWs to
meet numeric limits for such pollutants by 1977. The limits were based on the use of
"secondary treatment"—the breakdown of organic matter by microorganisms. Although
secondary treatment may remove some toxic pollutants (such as heavy metals or manmade
organic compounds) on an incidental basis, the CWA instead provides for control of toxics
through POTW pretreatment programs and industrial compliance with numeric pretf eatment
standards.
i ' . ' • •
1-2
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In addition to meeting secondary treatment requirements, POTWs may also be required
to meet permit limits based on water quality standards: that States develop under Section 303
of the CWA. These standards protect the quality of individual water bodies. To establish
water quality standards, States designate desired uses for stream segments, such as fishing,
swimming, water supply, or industrial use. Ambient Federal or local water quality criteria are
applied to the most sensitive use for each stream and become the operative water quality
standards. These, in turn, may be translated into effluent limits in NPDES permits to protect
water quality and designated uses.
POTWs are also subject to restrictions on how they may dispose of the sewage sludge
generated by their treatment operations. POTWs impose pretreatment controls on their
industrial .users not only to protect receiving waters but also to ensure that sewage sludge is
of sufficient quality for the disposal or beneficial use intended. Sewage sludge may be
landfilled or incinerated, or, if it contains low enough quantities of toxic pollutants, it may be
used as a fertilizer or soil conditioner.
Until recently, control of the disposal of municipal sewage sludge was regulated on a
State-by-State basis, and POTW operators rarely had access to comprehensive criteria that
would enable them to place appropriate pretreatment controls on their industrial users.
Regulations defining acceptable land disposal practices and beneficial use for sludge (40 CFR
Part 257) have been promulgated under the joint authority of the CWA and Subtitle D of the
Resource Conservation and Recovery Act (RCRA). Other laws governing municipal sludge
use or disposal depend on the use or disposal method employed or the pollutants present in
the sludge. These laws include the Clean Air Act; the Marine Protection, Research, and
Sanctuaries Act; RCRA Subtitle C; and the Toxic Substances Control Act.
EPA is now preparing regulations mat will control the management of municipal sewage
sludge in a much more comprehensive manner. These regulations are under the authority of
Section 405 of the CWA, as amended by Section 406 of the WQA of 1987. This provision
requires EPA to regulate sludge use and disposal to protect public health and the
environment from any reasonably anticipated adverse effects of these practices.
One of the most prevalent sludge disposal methods nationwide is disposal at a
municipal landfill. This practice will be covered by regulations that have been proposed at 40
CFR Part 258 for operation and maintenance of municipal landfills.,
1-3
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EPA is also developing technical standards for other sludge use and disposal options,
including land application, that .will be incorporated into NPDES permits or other permits
issued to POTWs. These standards will make it easier for POTWs to control the quality of
their sludge by setting effluent limits for their industrial users that will allow POTWs to meet
whichever standards apply to their own sludge disposal practices.
EPA has proposed an initial round of sludge standards that are expected to be published
in early 1992 at 40 CFR Part 503. Until the Part 503 standards are promulgated, EPA is
regulating sewage sludge use and disposal practices through a congressionally mandated
interim permitting program that places case-by-case sludge conditions in NPDES permits.
1.1.2 The Role of the National Presentment Program
NPDES permits issued to POTWs protect two media: receiving waters and sewage
sludges. To comply with its NPDES permit and meet other environmental criteria, a POTW
must limit the pollutants it receives that are not amenable to treatment at its own plant.
Typically, POTWs receive a mixture of two types of waste: domestic sewage from
residential and commercial sources, and industrial wastewaters discharged into the sewer.
Industrial wastes frequently contain toxic pollutants, such as heavy metals or manmade
organic chemicals, that may not be compatible with the physical and biological processes that
POTWs typically use to treat wastes. Such toxic pollutants may pass through wastewater
treatment plants untreated or interfere with treatment plant operations. Therefore, POTWs
may require industrial users to "pretreat" wastewaters discharged to municipal sewers.
Local industrial waste controls have existed in some cities for many years. Milwaukee,
Wisconsin, for example, has regulated discharges of industrial wastewaters to sewers since
the 1920s. (The success of this program is shown most clearly in the widespread marketing
of the fertilizer Milorganite, which is a sewage sludge product.)
' , . ' ' i ' "•' , ' ,
The Federal Government's role in pretreatment was first established with the Federal
Water Pollution Control Act Amendments of 1972. Section 307(b) of the 1972 Amendments
required EPA to promulgate technology-based pretreatment standards for industrial users of
POTWs that would prevent pollutant discharges that interfere with POTW operations, pass
through treatment works to receiving waters without adequate treatment, hinder proper use
or disposal of sewage sludge, or are otherwise incompatible with the POTW.
1-4
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The Clean Water Act Amendments of 1977 contained a more comprehensive approach
to pretreatment that gave greater attention to toxic pollutants. As a result, EPA promulgated
the General Pretreatment Regulations in 1978 (40 CFR Part 403). The Agency adopted
these regulations after considering many alternative strategies concerning the number of
industrial users to be regulated, the amount of local flexibility allowed, and the relative roles
of Federal, State, and local governments.
The pretreatment program has three objectives:
1. Prevent interference with treatment plant operations. Some nondomestic pollutants
are incompatible with POTW treatment systems and can disrupt plant operations
and reduce treatment efficiency. Interference is defined in the General Pretreatment
Regulations (40 CFR 403.3[i]) as:
A discharge which, alone or in conjunction with a discharge or
discharges from other sources, both: (1) inhibits or disrupts the
POTW, its treatment processes or operations, or its sludge
processes, use or disposal; and (2) therefore is a cause of a
violation of any requirement of the POTWs NPDES permit
(including an increase in the magnitude or duration of a violation)
or of the prevention of sewage sludge use or disposal in
compliance with ;. „ [applicable] statutory provisions and
regulations or permits issued thereunder (or more stringent
State or local regulations)...
2._ Prevent pass through of pollutants to receiving waters. Even if nondomestic
pollutants do not interfere with treatment systems, they may pass through POTWs
without being treated adequately. The General Pretreatment Regulations (40 CFR
403.3[n]) define pass through as:
A discharge which exits the POTW into waters of the United
States in quantities or concentrations which, alone or in
conjunction with a discharge or discharges from other sources, is
a cause of a violation of any requirement of the POTWs NPDES
permit (including an increase in the magnitude or duration of a
violation).
3. Improve opportunities to recycle and reclaim municipal and industrial wastewaters
and sludges. Certain pollutants are "partitioned" from wastewater to sewage
sludge by the POTW's treatment system. Contamination of sludge by toxic
pollutants can increase disposal costs or limit disposal options. Pollutants
remaining in the municipal wastewater can limit opportunities for water reuse.
Additionally, many pretreatment technologies provide for reclamation of lost raw
materials by industrial users, or are substituted by pollution prevention practices
that eliminate the need for end-of-pipe treatment.
1-5
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1.1.3 Responsibilities for Implementing the National Pretreatment Program
EPA's General Pretreatment Regulations establish the framework, responsibilities, and
requirements for implementing and enforcing pretreatment standards. EPA established the
National Pretreatment Program on the premise that the program's goals would best be met
through the interaction of Federal, State, and local governments. Local governments bear the
primary responsibility for developing, carrying out, and enforcing local pretreatment programs.
This is because POTWs:
• Know their own nondomestic users and are best placed to develop effective controls
on those users
• Are in the best position to diagnose and correct problems unique to their systems
• Can respond to emergencies and can take quick, effective action to address
environmental hazards. •
The Federal Government and the States also share responsibility for carrying out the
National Pretreatment Program. State and Federal approval authorities review, approve, and
oversee local pretreatment programs and regulate discharges to any POTWs that do not have
V • :
such local programs.
States that are authorized to run the NPDES Program at the State level must apply for
authority to administer pretreatment requirements as well. States are designated as
"approval authorities" after EPA reviews and approves their State pretreatment programs.
Currently, as illustrated in Figure 1-1, 39 States have federally approved NPDES permit
programs, and 27 States have approved State pretreatment programs. EPA is the approval
authority in States without approved pretreatment programs.
Under 40 CFR 403.10(e), approved States may choose to regulate industrial users
directly instead of requiring POTWs to do so through local programs. Alabama, Connecticut,
Mississippi, Nebraska, and Vermont currently are "403.10(e) States" that run the National
Pretreatment Program at the State level in lieu of local programs.
EPA develops industry-specific national categorical pretreatment standards, oversees
approved State programs, makes necessary changes to the General Pretreatment
Regulations, and exercises its enforcement authority to ensure that industrial users and
i
1-6
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.s
.. I
Q
2
S,
1-7
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POTWs comply with pretreatment standards and requirements. The Agency also provides
extensive training and technical assistance to States and POTWs.
1.1.4 POTWs Required to Have Pretreatment Programs
Unless they are located in States that have chosen to assume responsibility for local
program functions under 40 CFR 403.10(e), the following POTWs must have pretreatment
programs pursuant to 40 CFR 403.8(a):
• POTWs with design flows exceeding 5 million gallons per day (mgd) are required to
have pretreatment programs if the discharges from their industrial users are subject
to pretreatment standards (described below) or cause pass through or interference.
• POTWs with 5 mgd design flow or less may also be required to have pretreatment
programs depending on the nature or volume of their industrial influent, particularly if
a potential exists for upsets of treatment processes, violations of NPDES permit
requirements, or contamination of sewage.sludge.
POTWs meeting these criteria were required to develop pretreatment programs by
July 1, 1983. POTWs identified since that time as requiring programs are required to submit
programs for approval within 1 year of identification.
EPA's 1988 NEEDS Survey (described in Chapter 2 and hereafter referred to as
NEEDS '88) identified 15,591 wastewater treatment plants nationwide. Among these
plants, 1,542 POTWs are required to develop and implement local pretreatment programs. Of
these, 1,442 programs have been approved and are being implemented. These approved local
pretreatment programs cover 2,015 individual wastewater treatment plants, or 13.6 percent of
the total number of plants in the country (note that a pretreatment program may cover more
than one plant). One hundred pretreatment programs, covering 113 plants, remain to be
approved. ,
Figure 1-2 illustrates the number of approved local programs in each State. EPA
Regions IV and V have the most approved pretreatment programs, representing roughly half
of the national total. North Carolina, Michigan, and California are the States with the highest
numbers of approved POTW programs. As Figure 1-3 reveals, most local programs were
approved before 1986. In addition, the so-called "403.10(e)" States (where States rather
than local POTWs implement pretreatment requirements) regulate discharges to about 314
POTWs.
1-8
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1-9 '
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To analyze the characteristics of POTWs with and without approved pretreatment
programs, EPA merged two of its national data bases: NEEDS '88 and Permit Compliance
System (PCS). Chapters 2 and 6 describe these data bases in more detail. This data merge
yielded statistics on approximately 12,000 POTWs, or roughly 80 percent of the 15,591
POTWs in the country. (It should be noted that all data were hot available for all POTWs.
The number of POTWs for which specific data were available varied depending on the specific
data need and the data source. Numbers of POTWs may therefore be inconsistent from one
table or analysis to another in this'report)
- - •.-•'' ' ,.-'».
As Table 1-1 indicates, large POTWs are represented heavily in the pretreatment
program and contribute a high percentage of the total national wastewater flow, although they
represent only a small number of all POTWs in the country.
Table 1-2 shows the levels of treatment provided at POTWs, indicating that the
majority of both pretreatment and nonpretreatment POTWs provide secondary treatment.
Many provide greater than secondary treatment, while a considerably smaller percentage
provides less than secondary treatment. (As discussed in Chapter 4, secondary treatment
involves bacterial stabilization of organics.v Less than secondary treatment involves only the
settling of sewage solids.)
Finally, Table 1-3, which characterizes the receiving waters to which POTWs
discharge, shows that at least 80 percent of all POTWs discharge to streams or rivers.
1.1.5 Pretreatment Standards
POTWs required to have local pretreatment programs must develop and implement
pretreatment requirements as needed to prevent pass through and interference, identify users
subject to pretreatment requirements, issue control mechanisms to those users, monitor
compliance, and take timely and appropriate enforcement actions against users who violate
pretreatment requirements. One of the most important elements of local programs is the
requirement that POTWs impose numerical limitations (local limits) to prevent pass through
or interference from the industrial pollutants discharged into their sewer systems.
Pretreatment standards consist of national prohibited discharge standards, national
categorical standards, and local limits. ~
l-ll
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Table 1-1. Distribution of POTWs by Design Flow Rates
Design Flow
(mgd)
£1.0
L0< - £5.0
5.0< - £10.0
10.0< - £25.0
25.0< - £50.0
50.0< - £100.0
>100.0
TOTAL
Pretreatment POTWs*
Number of
Plants
421
793
366
303
128
52
44
2,107
Total Flow
(mgd)
213
2,258
2,782
4,915
4,606
3,928
9,762
28,464
Nonpretreatment POTWs**
Number of
Plants
8,644
1,361
83
19
3
0
0
10,110
Total Flow
(mgd)
2,175
3,002
584
246
109
' —
1 —
6,116
* POTWs covered by approved local pretreatment programs, POTWs covered by programs
currently under development, and POTWs in Alabama, Connecticut, Mississippi,
Nebraska, and Vermont with industrial users regulated by States.
** All other POTWs.
Source: POTWs represented in both PCS and NEEDS '88.
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Table 1-2. Types of Treatment Provided by Pretreatment
and Other POTWs
Level of
Treatment1
Less Than
Secondary
Secondary
Greater
Than
Secondary
Total
Pretreatment POTWs2
POTWs
Number
179
1,081
, 827
2,087
Percentage
8.5
51.8
39.6
100
Percentage
of Total
Flow
15.6
40.9
43.5 .
100
Nonpretreatment POTWs3
POTWs
Number
1,354
6,217
2,169
9,740
Percentage
13.9
63.8
22.3
100
Percentage
of Total
Flow
N/A
N/A
N/A
100
1. Categories defined by NEEDS'88:
• Less than secondary: Primary (BOD>45 mg/1) and Advanced Primary (BOD>31 and
<45 mg/1)
• Secondary (BOD>24 and <30 mg/1 or 85% removal)
• Greater than secondary: Advanced Treatment I (BOD^IO and <23 and/or nutrient
removal); Advanced Treatment n (BOD<10 and/or nutrient removal).
2. Includes POTWs,covered by approved local pretreatment programs, POTWs with local
programs under development, and POTWs in Alabama, Connecticut, Mississippi,
. Nebraska, and Vermont with industrial users regulated by the States.
3. Includes all other POTWs.
, -•-•',' . ' . • f
Source: NEEDS'88 for POTWs with appropriate datai
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Table 1-3. Types of Receiving Waters to Which POTWs Discharge
Receiving
Water
Type
Rivers and
Streams
Great
Lakes
Other
Lakes
Ocean
Other3
TOTAL
Pretreatment POTWs1
POTWs
Number
1,634
33
53
132
174
2,026
Percentage
80.1
1.6
2.6
6.5
8.6
100
Average
Daily Flow
Per POTW
(mgd)
7.8
25.8
4.1
32.16
18.07
Nonpretreatment POTWs2
POTWs
Number
8,641
63
307
243
442
9,696
Percentage
89.1
0.6
3.2
2.5
4.6
100
Average
Daily Flow
Per POTW
(mgd)
0.4
0.5
0.3
1.3
0.9
1. Includes POTWs covered by approved local pretreatment programs, POTWs with local
programs under development, and POTWs in Alabama, Connecticut, Mississippi,
Nebraska, and Vermont with industrial users regulated by the States.
2. Includes all other POTWs.
3. Includes discharges to waters not classifiable as to type (discharge to island shorelines,
some estuaries, and ocean shorelines, and stream discharge to ocean/lake/ground).
Source: NEEDS '88 for POTWs with appropriate data.
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1.1.5.1 Prohibited Discharge Standards
Prohibited discharge standards (40 CFR 403.5) forbid certain types of discharges by any
nondomestic user to the wastewater collection system of any POTW, including POTWs
without local pretreatment programs. The prohibited discharge standards consist of general
and specific prohibitions.
General prohibitions are national prohibitions against pollutant discharges to a POTW
that cause pass through or interference. As defined in 40 CFR. 403.3(n), pass through occurs
when a pollutant remains in the treatment plant's wastestream without undergoing sufficient
treatment or removal, causing a violation of the POTW's NPDES permit. Interference (40
CF/J 403.3[i]> occurs when a discharge inhibits or disrupts the POTW's treatment processes
or operation, thereby either causing a permit violation or precluding permitted sludge
beneficial use or disposal practices.
Specific prohibitions are national prohibitions against pollutant discharges that cause
problems at the POTW, such as fire or explosion, harm to worker health and safety,
corrosion, obstruction of flow, or inhibition of treatment processes due to heat or oil and
grease. "
1.1.5.2 National Categorical Pretreatment Standards
Whereas the general and specific prohibited discharge standards apply to all
nondomestic users, national categorical pretreatment standards (categorical standards) apply
to industrial users with specified industrial processes. Each categorical standard covers a
different industrial category. Under the CWA, categorical standards are technology-based;
they require dischargers to meet end-of-process limits developed according to the Best
Available Technology Economically Achievable (BAT) for each category.
Categorical standards are expressed as Pretreatment Standards for Existing Sources
(PSES) and Pretreatment Standards for New Sources (PSNS). EPA has promulgated PSES
and PSNS for the industrial categories shown in Table 1-4. Industrial dischargers subject to
categorical standards are known as categorical industrial users (CIUs).
Categorical standards may limit any pollutant (most include at least some criteria for
conventional and nonconventional pollutants), but they emphasize the control of 126 toxic
pollutants that have been designated "priority pollutants." These priority pollutants are the
result of a 1976 consent decree between EPA and the Natural Resources Defense Council;
under which EPA agreed to promulgate technology-based standards for 65 classes of toxic
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Table 1-4. Status of Categorical Standards
Industrial Categories With Categorical Standards
in Effect
E N Aluminum Forming
E N Asbestos Manufacturing
E N Battery Manufacturing
E N Builder's Paper and Board Mills
N Carbon Black Manufacturing
E N Cement Manufacturing
E N Coil Coating
E N Copper Forming
E N Dairy Products Processing
E Electroplating
E N Electrical and Electronic Components
E N Feedlots
N Ferroalloy Manufacturing
N Fertilizer Manufacturing
E N Fruits and Vegetables Processing
N Glass Manufacturing
E N Grain Mills Manufacturing
N Ink Formulating
E N Inorganic Chemicals
E N Iron and Steel Manufacturing
E N Leather Tanning and Finishing
E N Meat Products . .
E N Metal Finishing
E N Metal Molding and Casting
E N Nonferrous Metals Forming and Metal
Powders
E N Nonferrous Metals Manufacturing
E N Organic Chemicals, Plastics, and Synthetic
Fibers
N Petroleum Refining
N Pharmaceutical Manufacturing
N Plastics Molding and Forming
N Porcelain Enameling
N Pulp, Paper, and Paperboard
N Rubber Manufacturing
N Seafood Processing
N Soap and Detergent Manufacturing
N Steam Electric Power Generating
N Sugar Processing
N Textile Mills
N Timber Products Processing
i Standards in effect for existing sources.
= Standards in effect for new sources.
Categories for Which New Categorical Standards
Being Developed
Hazardous Waste Treatment, Phase I (facilities
treating aqueous wastewaters)
Machinery Manufacturing and Rebuilding
Pesticide Chemicals
Categories for Which Guidelines Are Being
Revised
Organic Chemicals, Plastics, and Synthetic Fibers
Pharmaceutical Manufacturing
Pulp, Paper, and Paperboard
Categories for Which Categorical Standards
Being Reviewed For Possible Revision
Petroleum Refining
Textile Mills
Timber Products Processing
Categories Being Studied for Possible
Development of Categorical Standards
Drum Reconditioning
Hospitals
Industrial Laundries
Oil and Gas Extraction—Stripper Subcategory
Paint Formulating
Solvent Recycling
Transportation Equipment Cleaning
Used Oil Reclamation and Re-Refining
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compounds for 34 industrial categories. The 129 priority pollutants were derived from the
original 65 classes of compounds, later removing 3 from consideration. Standards for each
category are established for the pollutants of concern for that category, so the number of toxic
pollutants regulated varies from category to category. For example, the pulp, paper, and
paperboard category regulates 3 priority pollutants, while the organic chemicals, plastics, and
synthetic fibers category regulates more than 40.
EPA is continuing to evaluate industrial categories to determine whether additional
standards are needed. Section 304(m) of the WQA requires EPA to publish a plan every 2
years that schedules annual review and revision of effluent guidelines, including categorical
standards. Studies being conducted as part of this mandate' are discussed in more detail in
Chapter 3. Chapter 5 addresses the pollutants and industries currently covered by
categorical standards.
1.1.5.3 Local Limits.
National prohibited discharge standards and categorical standards are not always
sufficient to protect POTWs from pass through and interference. For this reason, the
National Pretreatment Program also provides for local limits, which are discharge standards
developed and enforced at the local level. Local limits are also federally enforced pursuant to
40 CFR 403.5(d).
Local limits take local circumstances into account; they also translate prohibited
discharge standards and other State and local requirements into numeric effluent limits. Local
limits are considered "technically based" if they are developed to ensure plant compliance
with discharge standards in NPDES permits, sludge disposal requirements, and applicable
Federal, State, and local environmental criteria. In certain cases, they should also be
developed to protect worker health and safety. When a local limit and a categorical standard
both exist for the same discharge, the more stringent of the two limits must be enforced.
All POTWs with approved pretreatment programs are required to develop and enforce
local limits and to evaluate, every 5 years, whether their limits need to be revised.
Nonpretreatment POTWs must also develop local limits if they have experienced pass
through or interference problems that are likely to recur. Local limits developed to prevent
pass through or interference are enforceable at the Federal and State level as well as by
POTWs. Chapter 5 describes in more detail how POTWs develop local limits.
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1.1.6 Significant Industrial Users
Although hundreds of thousands of industrial and commercial sources nationwide
discharge wastes to sanitary sewers, not all require the same degree of control and
oversight. For this reason, EPA in 1986 recommended through national guidance that
POTWs use EPA's definition of significant industrial user (SIU). On July 24, 1990
(55 FR 30082), EPA promulgated revisions to the General Pretreatment Regulations that
provided a standard definition of SIU. Generally, an SIU is defined at 40 CFR 403.3(t) as:
• Any user subject to a categorical pretreatment standard, also known as a CIU
• Any other industrial user that discharges an average of 25,000 gallons per day or
more of process wastewater, or that contributes a process wastestream making up 5
percent or more of the average dry weather hydraulic or organic capacity of the POTW
treatment plant
• Any other user designated as an SIU by the control authority (generally because of
potential for adverse impact).
EPA estimates that POTWs with approved pretreatment programs regulate about
11,600 CIUs and about 18,400 other SIUs—an average of over 10 users per program.
Approximately 800 CIUs and SIUs discharge to nonpretreatment POTWs and, thus, are
subject to regulation by EPA Regions and States rather than by POTWs.
1.2 PREVIOUS ASSESSMENTS OF THE NATIONAL PRETREATMENT PROGRAM
Several studies have been conducted of various elements of the National Pretreatment
Program since its inception. The evaluations performed for this Report to Congress have
taken into account these previous studies, the more important of which are discussed in this
section.
1.2.1 Pretreatment Regulatory Impact Analysis
EPA promulgated its General Pretreatment Regulations on June 26, 1978, and amended
them on January 28, 1981. Pursuant to Executive Order 12291, which requires that
Regulatory Impact Analyses (RIAs) be conducted to analyze the costs and benefits of major
pending regulations, EPA completed an RIA of the General Pretreatment Regulations on
November 20, 1981 (EPA, 1981).
The Pretreatment RIA compared the design of the existing program to several other
less stringent options, such as covering fewer industries, employing water quality concerns
as "triggers" for program development, and making the pretreatment program a voluntary
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program with guidance from the Federal Government. It concluded that the benefits of the
existing program (such as reduced toxic pollutant loadings to effluent and sludge, reduction in
exceedances of water quality criteria, prevention of worker health and safety problems, and
improvement in plant operations and integrity) outweighed program costs.
The Pretreatment RIA also demonstrated the importance of effective control of
industries by POTWs and the need for pretreatment to reduce loadings of toxic pollutants.
EPA, therefore, recommended to Congress that local program implementation remain a
cornerstone of the National Pretreatment Program and endorsed national categorical
pretreatment standards as a principal way to reduce toxic pollutant loadings to POTWs.
1.2.2 Assessment of Industrial Waste Control Programs in Three Municipalities
The next important study of the National Pretreatment Program was the Assessment of
Industrial Waste Control Programs in Three Municipalities (EPA, 1983; also known as the
Three-City Study), prepared by EPA and submitted to Congress on September 13, 1983.
Although the Pretreatment RIA had demonstrated the potential effectiveness of the
General Pretreatment Regulations and categorical standards, a debate arose about the need
for federally mandated pretreatment programs in large cities that had independently
undertaken their own industrial waste programs. A bill was introduced in Congress to
exempt large municipalities with well-operated programs from Federal pretreatment
requirements, and Congress directed EPA to study the issue.
The Three-City Study examined whether the independently developed programs of
three municipalities (Los Angeles, Chicago, and Passaic Valley) could be shown to
accomplish goals substantially equivalent to the National Pretreatmen,t Program, although
their programs differed procedurally from the requirements set forth in 40 CFR Part 403. The
study found that although the three cities had achieved significant industrial waste control,
their programs were deficient in legal authorities (especially in the multijurisdictional area),
identification of industries, monitoring, permitting, and enforcement; this resulted in NPDES
permit violations and documented environmental problems.
The study projected that complete implementation of categorical pretreatment standards
at the three cities would reduce toxic organic and metal pollutant loadings in effluent and
sludge, eliminate noncompliance problems, and ameliorate environmental problems. EPA,
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therefore, recommended that Congress not enact a waiver from pretreatment requirements for
large cities.
1.2.3 Pretreatment Implementation Review Task Force
In 1984, EPA convened the Pretreatment Implementation Review Task Force (PIRT)
consisting of EPA Headquarters and regional personnel, State officials, POTW officials,
environmental groups, and industry representatives. The purpose of PIRT was to identify
problems in implementing the existing pretreatment program and to recommend measures
that would rectify those problems. PIRT relied primarily on the experience of task force
members in program implementation and did not collect or evaluate new data as part of the
report.
In response to the 1985 PIRT report, Pretreatment implementation Review Task Force:
Final Report to the Administrator (EPA, 1985), EPA developed additional guidance and
policy documents and promulgated amendments to the General Pretreatment Regulations hi
1987 and 1988 that responded to many of PIRTs recommendations.
1.2.4 Domestic Sewage Study
On February 7, 1986, EPA submitted the Report to Congress on the Discharge of
Hazardous Wastes to Publicly Owned Treatment Works (EPA, 1986), also known as the
Domestic Sewage Study (DSS). The DSS was required by Section 3018(a) of the 1984
Hazardous and Solid Waste Amendments to RCRA, in which Congress directed EPA to
evaluate the impacts of wastes discharged to POTWs as a result of the Domestic Sewage
Exclusion (DSE).
The DSE (RCRA Section 1004[27], codified in 40 CFR 261.4[a][l]), provides that solid
or dissolved material in domestic sewage is not a solid or a hazardous waste under RCRA.
The exclusion allows industries to discharge hazardous wastes to POTW sewers containing
domestic sewage without having to comply with many RCRA requirements, such as
manifesting and reporting, that otherwise apply to facilities that generate, hazardous waste.
Moreover, POTWs receiving DSE wastes are not deemed to receive hazardous wastes and,
therefore, are not subject to RCRA requirements for hazardous waste treatment, storage, and
disposal facilities.
The rationale for the DSE is that exempted wastes are regulated adequately under the
National Pretreatment Program and that management of such wastes under RCRA would be
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redundant. To determine whether DSE wastes were indeed being controlled adequately
under the exemption, or whether regulation under RCRA would also be necessary, Congress
directed EPA to study:
• The types* sizes, and number of facilities discharging wastes under the DSE
. \ ..- • " .
• The types and quantities of wastes disposed of under the DSE
• Significant generators, wastes, and constituents not sufficiently regulated to protect
human health and the environment.
The DSS concluded that the DSE should be retained and that the National Pretreatment
Program, with changes to strengthen control of hazardous wastes, could control hazardous;
waste discharges to sewer systems sufficiently to protect public health and the environment.
The DSS recommended that EPA consider the following measures to improve controls on
hazardous waste discharges to sewers:
• Additional research on the sources, quantities, fates, and effects of hazardous waste
discharges to sewers and on additional regulatory controls that might be necessary
* Improvements to categorical standards and local limits to control such discharges
• Strengthened implementation and enforcement of CWA requirements
• Identification and application of pertinent environmental controls under other
environmental statutes as necessary.
Section 3018(b) of the 1984 Amendments to RCRA also directed EPA to revise existing
regulations and to promulgate additional regulations as necessary to ensure that hazardous
wastes discharged to POTWs would be controlled adequately to protect human health and
the environment. Pursuant to that mandate, EPA promulgated amendments to the General
Pretreatment Regulations on July 24, 1990 (55.'PR 30082). The regulations, effective August
23,1990:
• Prohibit the introduction to POTWs of wastestreams with a closed-cup flashpoint of
less than 140T (to prevent fires and explosions at POTWs)
• Prohibit the introduction to POTWs of pollutants that result in gases, vapors, and
fumes in quantities that may cause acute worker health and safety problems
• Prohibit discharges of petroleum oil, nonbiodegradable cutting oil, or mineral oil
products in amounts that would cause interference or pass through
• Prohibit the discharge of trucked or hauled wastes except at discharge points
designated by the POTW
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• Provide definitions of significant industrial user and significant noncompliance
• Require each POTW with an approved pretreatment program to determine, at least
once every 2 years, which of its SIUs need a plan to control spills and batch
discharges
• Require one-time notification by each industrial user of each hazardous waste being
discharged to the sewer system and certification that it has a waste minimization
program in place
• Require each POTW with an approved pretreatment program to issue permits or
equivalent individual control mechanisms to its SIUs
• Require certain POTWs (including all POTWS with local pretreatment programs) to
submit the results of whole-effluent toxicity testing with their NPDES permit
applications (i.e., at least every 5 years)
• Require all pretreatment POTWs to evaluate the need to revise local limits as part of
their NPDES permit applications (i.e., at least every 5 years)
• Require stricter monitoring and. reporting requirements for SIUs
• Require POTWs with approved pretreatment programs to develop enforcement
response plans detailing how they will respond to industrial user violations.*
' \ ! ', " - ' -
' •" • • ' • ;
1.2.5 General Accounting Office Report
In April 1989, the U.S. General Accounting Office (GAO) released a report entitled,
Improved Monitoring and Enforcement Needed for Toxic Pollutants Entering Sewers (GAO,
1989). The GAO undertook the report to assess enforcement of the National Pretreatment
Program, including the extent to which industrial users were in noncompliance with discharge
limitations, enforcement by POTWs against noncompliant industrial users, and EPA and
State oversight of the efforts by POTWs to implement and enforce the program.
i, '
The GAO report recommended the following measures to improve enforcement of the
pretreatment program:
• POTWs lacking appropriate enforcement standards should be required to apply EPA
standards against noncompliant industrial users.
• EPA standards should be applied against POTWs failing to implement pretreatment
programs. • -..'..
« EPA should direct Federal and State approval authorities to review the adequacy of
sampling frequencies, sampling locations, and local limits employed by POTWs and
require correction of any deficiences found.
In October 1989, EPA announced a major enforcement initiative against POTWs that
had failed to carry out their responsibilities under the National Pretreatment Program. The
.*
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enforcement initiative involved 413 enforcement actions taken against POTWs; 61 of these
POTWs were targeted for administrative penalty orders or judicial enforcement. The DSS
regulations promulgated on July 24, 1990, also addressed concerns raised in the GAO report,
including the need for increased monitoring and for POTWs to develop enforcement response
plans. Chapter 7 discusses current enforcement-related activities.
1.2.6 Report to Congress on Hydrogen Sulfide Corrosion .
EPA is finalizing the Report to Congress on Hydrogen Sulfide Corrosion in Wastewater
Collection and Treatment Systems (Sulfide Corrosion Study). The Sulfide Corrosion Study
was required by Section 522 of the Water Quality Act of 1987. EPA was required to study
the corrosive effects of hydrogen sulfide in wastewater collection and treatment systems, the
extent to which uniform imposition of categorical pretreatment standards exacerbates this
corrosion problem, and the range of available options to deal with such effects.
With respect to the second requirement of Section 522—that EPA investigate the role
of pretreatment in hydrogen sulfide corrosion^-EPA conducted a case study at the County
Sanitation Districts of Los Angeles County (CSDLAC). The executive summary of the
Hydrogen Sulfide Study discusses the findings of this case study as follows:
2.2 Effects of Industrial Pretreatment
The national effects of industrial pretreatment on hydrogen sulfide
corrosion are very difficult to ascertain since no sanitation districts other than
CSDLAC were found to have sufficient data to establish a correlation. Based
on theoretical analysis, review of full scale and pilot scale research data from
CSDLAC, and a series of site investigations, the following conclusions are
presented.
• The reduction in metals and other industrial constituents in CSDLAC
wastewater may have caused an acceleration in corrosion rate,
possibly due to decreased biological inhibition and/or chemical
precipitation.
• Two pilot studies conducted by CSDLAC demonstrated that sulfide
generation was reduced when metals were added to the wastewater
at levels approximating those in the early 1970s. (This is consistent ,
with the known toxic effects of metals on other microorganisms.)
• When compared with data from 50 other wastewater treatment
plants in the 1970s, total metals and cyanide levels in the CSDLAC
wastewater were higher than levels in wastewater entering 47 of the
50 facilities. While 32 percent of the cities had total metals and
cyanide levels higher than CSDLAC levels after pretreatment, it is
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difficult to project how many cities could potentially have a corrosion
problem affected by industrial pretreatment since it is not known at
what levels industrial constituents begin to suppress sulfide
generation. - ,
• Data comparing corrosion in residential versus industrial sewers
were inconclusive, as to whether metals suppressed hydrogen sulfide
corrosion.
• Local regulation of certain nontoxic constituents in industrial waste
discharges (BOD, sulfide, temperature, pH) has had a beneficial
impact hi reducing the potential for hydrogen sulfide corrosion. .
• Additional research is necessary to establish the constituents and
their associated levels at which sulfide generation is suppressed or
accelerated.
The complete draft text of Chapter 3 of the Sulfide Corrosion Study is provided as
Appendix E of this Report to Congress.
1.3 SUMMARY
The National Pretreatment Program has been the object of intense scrutiny. Several
studies have been, submitted to Congress and reviewed in committee hearings. Each major
study has concluded that the National Pretreatment Program is essentially sound; all have
found that controls beyond categorical standards, as well as improved enforcement, may be
necessary to meet environmental objectives.
Despite these similarities, the conclusions of each study reflected different concerns
about the program. For example, the Pretreatment RIA showed that the benefits of the 1981
program outweighed its costs, the Three-City Study resulted in an EPA recommendation that
Congress drop consideration of municipal pretreatment waivers, and the DSS led to modifica-
tions to the pretreatment program that strengthened control over hazardous wastes dis-
charged to sewers.
Little beyond the express language of Section 519 indicates congressional intent for this
Report to Congress. The only reference to this report in the legislative history is contained in
the report from the House Committee that initially developed Section 519 (then referred to as
Section 47):
, , . i • '• ' i
Section 47 requires the Administrator to study the effectiveness of
the National Pretreatment Program. This study is not intended to
determine the need for pretreatment or in any way to delay ongoing
program implementation. Rather, the study should be used to
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update and expand information available to the Agency on such
matters as the impact on publicly owned treatment works of
industrial discharges and the pollution removal effectiveness of
publicly owned treaitment works technology. In addition, the study
should be used to evaluate the effectiveness—both in terms of
pollutant removal and cost—of industrial pretreatment controls.
Section 47(a)(3) requires the Administrator to study the capability • • ,
of publicly owned treatment works to revise pretreatment
requirements under section 307(b)(l) of the Federal Water
Pollution Control Act. The Committee intends that EPA focus
particular attention on the extent to which EPA's pretreatment
removal credits program is presently effectuating the Congressional
intent behind section 307(b)(l). Congress added the credits
system to the Act in 1977 because of its concern that EPA's
categorical pretreatment standards could result in costiy redundant
treatment by industry and publicly owned treatment works. The
Committee also intends that, in implementing section 47(a)(3), the
Administrator shall examine the capability of publicly owned
treatment works to establish and enforce requirements more
stringent than or different from national categorical standards.
The Committee's reference in section 43(a)(4) to possible alter-
native regulatory strategies is meant to include, among other things,
consideration of sludge quality in evaluating strategy effectiveness.
Section 43(a)(5)'s reference to adequacy of ... resources is meant ,
to include evaluation of technical expertise and availability of
analytical methods as well as financial and staffing level
evaluations.
The legislative history makes it clear that Congress did not intend for EPA to justify the
existence of the pretreatment program or to conduct a regulatory impact analysis. Therefore,
for example, EPA is not estimating the costs of the existing program but rather the costs
associated with potential alternative regulatory strategies (Chapter 8). Initial costs of the
pretreatment program were estimated in the 1981 RIA, and, per Executive Order 12291,
subsequent costs to industrial users continue to be evaluated during development of national
categorical standards and amendments to 40 CFR Part 403. Rather, Congress intended this
report to examine alternative means of improving the program, considering the effectiveness
of each option in attaining the objectives of the Clean Water Act.
1.4 ORGANIZATION OF Tms REPORT TO CONGRESS
This Report to Congress provides a comprehensive evaluation of the National
Pretreatment Program, with particular emphasis on those areas specified in Section 519. The
objective of this evaluation is to determine, now that implementation of the National
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Pretreatment Program is well underway, whether and how the program can achieve the goals
of the CWA more effectively and minimize the adverse environmental impacts of toxic
pollutants discharged to and from POTWs.
This report builds on, and broadens the scope of, the studies and evaluations discussed
in Section 1.2. As a thorough study of the National Pretreatment Program, it examines every
facet of the relationship between POTWs and toxic pollutants: the discharge to POTWs of
toxic pollutants by industrial and domestic sources, the fates of those pollutants in POTWs,
and the ultimate impacts of those pollutants in the environment to the extent currently known.
It also examines the environmental and programmatic effectiveness of the National
Pretreatment Program, explores a number of alternatives to me existing program, and
recommends several regulatory changes that would enhance program effectiveness.
Chapter 2 describes the data used for the report, describing EPA's use of national data
bases and supplemental State and local data sources. The chapter also identifies a number of
the major methodological decisions that affected the scope and findings of the report.
Chapter 3 characterizes the discharges of toxic pollutants to POTWs. It identifies the
sources of these pollutants and explores whether additional reductions in such discharges arc
possible and (implicitly) whether controls are needed for sources—such as domestic
sources—not currently regulated under the National Pretreatment Program. In addition to
evaluating industrial and domestic sources of toxic discharges, Chapter 3 identifies existing
and planned controls affecting such discharges, including the prohibited discharge standards,
national categorical pretreatment standards, local limits, spill prevention plans, and future
initiatives within the water, hazardous and solid waste, Superfund, and air programs. The
chapter also provides information on pollution prevention activities undertaken by various
industries.
Chapter 4 explores the extent to which secondary treatment removes toxic pollutants
from the wastestreams of POTWs. It describes the fate of toxic pollutants within POTWs,
differentiating bona fide removal (biodegradation) from volatilization to air and partitioning to
sludge, and it characterizes actual secondary treatment plant performance in removing toxic
pollutants from wastewater.
Chapter 5 evaluates the capability of POTWs to revise pretreatment standards through
two mechanisms: removal credits and local limits. The chapter describes the statutory and
» • . ' .
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regulatory history of the removal credits and local limits programs and discusses the
processes by which POTWs develop, submit, and implement these mechanisms. It also
describes existing Federal, State, and local environmental and technical criteria that influence
the protectiveness of removal credits and local limits, and provides an overview of the current
status of POTW development and implementation of removal credits and local limits. Finally,
the chapter details the evaluation of the technical capability of POTWs to grant removal
credits and to implement and enforce local limits.
Chapter 6 examines the environmental impacts of toxic pollutants discharged from
POTWs and assesses the extent to which data limitations affect the assessment of
environmental impacts. To characterize the receiving environments of POTWs, this chapter
provides information on the geographic location of POTWs, the nature of their receiving
waters and sludge disposal methods, and other demographic descriptors. Chapter 6 also
analyzes the extent to which POTWs comply with various environmental standards and
criteria, and it characterizes the adequacy and limitations of the data with which impacts are
assessed.
Chapter 7 evaluates the effectiveness of the existing National Pretreatment Program by
examining the following: whether POTWs are implementing the requirements of the program
effectively; whether the program covers the appropriate POTWs, pollutants, arid industries;
and whether the program has been effective in preventing or reducing the environmental
impacts of toxic pollutants discharged by POTWs. In addition, the discussion addresses
program implementation and identifies areas where POTWs have and have not met specific
program requirements. The chapter also analyzes the extent to which environmental
improvements can be attributed to implementation of the pretreatment program.
Chapter 8 explores alternative regulatory strategies for .enhancing the National
Pretreatment Program. It describes how the alternatives were selected and then
characterizes the purpose, scope, and affected parties for 17 supporting regulatory options.
Each alternative is evaluated for its applicability to CWA objectives and the findings of this
study. Finally, each alternative is assessed for its quantitative impacts (e.g., compliance
costs, number of regulatory actions) and attendant resource requirements.
•" ' , ' • v ' ' "
Chapter 9 summarizes the findings of each chapter and, based on those findings,
presents the report's final recommendations.
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REFERENCES
U.S. Environmental Protection Agency. 1986. Report to Congress on the Discharge of
Hazardous Wastes to Publicly Owned Treatment Works. 530-SW-86-004. Washington,
DC: Office of Water Regulations and Standards.
U.S. EPA. 1985. Pretreatment Implementation Review Task Force: Final Report to the
Administrator. Washington, DC: Office of Water Enforcement and Permits.
U.S. EPA. 1983. Assessment of Industrial Waste Control Programs in Three Municipalities.
Washington, DC: Office of Water Enforcement and Permits.
U.S. EPA. 1981. Assessment of the Impacts of Industrial Discharges on Publicly Owned
Treatment Works. Washington, DC: Office of Water Regulations and Standards.
U.S. General Accounting Office. 1989. Improved Monitoring and Enforcement Needed for
Toxic Pollutants Entering Sewers. GAO-RCED-89-101.
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3. STUDY APPROACH AND DATA SOURCES
This chapter describes the approach taken by the U.S. Environmental Protection Agency
(EPA) to evaluate the National Pretreatment Program as required by Sectipn 519 of the
Water Quality Act of 1987, and it provides an overview of the major data sources used in the
study. Section 2.1 summarizes a number of critical decisions made by EPA in designing the
study. This is followed by an overview, Section 2.2, of the data necessary to evaluate the
program fully. Section 2.3 identifies the principal data sources used in the study, with specific
information on origins and coverage. Lastly, Section 2.4 describes how a number of major
data sources were linked to expand the coverage .and-utility of the data that were used to
answer major study questions.
2.1 APPROACH
This Report to Congress provides information on all topics of inquiry set forth in Section
519, specifically (1) the adequacy of data on environmental impacts from the discharge of
toxic pollutants to publicly owned treatment works (POTWs), (2) the performance of
secondary treatment plants in removing toxic pollutants, (3) POTW capability to revise
pretreatment standards, and (4) alternative regulatory strategies for the pretreatment
program. This section presents an overview of the key aspects of EPA's approach; other
sections discuss the major data sources used in this report. Each subsequent chapter
provides greater detail on specific data sources and uses, as well as the adequacy of the
information upon which EPA relied. '
Several aspects of the congressional mandate, along with fundamental characteristics of
the National Pretreatment Program, influenced the Agency's approach. First, Congress
clearly intended a national assessment of a program that is inherently decentralized.
Furthermore, Congress required information on environmental impacts from a program that
relies on environmental standards not yet fully in place and on technology-based standards;
this made data acquisition problematic. Finally, as discussed in Chapter 1, the National
Pretreatment Program has undergone intensive examination several times in its relatively
brief history and EPA was determined to build upon and not simply duplicate previous efforts,
even though several topics of concern were similar in scope.
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All of these factors led EPA to define the study approach so that it would:
• Provide as comprehensive an assessment of the National Pretreatment Program as
possible
• Present actual results of the program rather than projected results (e.g., through the
use of actual monitoring and compliance data rather than modeling results)
• Draw upon and integrate data from across EPA program offices (e.g., Office of Water,
Office of Solid Waste and Emergency Response, Office of Air and Radiation)
• Make use of previous national studies relevant to this study's topics (e.g., the
Domestic Sewage Study [DSS], the 40-POTW Study)
• Integrate performance of the study with ongoing program implementation activities to
consolidate resources and make immediate use of findings (e.g., State and local
pretreatment program audit results)
• Supplement these data with State and local data to characterize the real world
accurately. .
Apparent in this approach are two overriding themes: a commitment to a multimedia
perspective and reliance on existing and readily available data. The following subsections
address these themes and their methodological implications.
2.1.1 Multimedia Perspective
Pollution control programs have focused traditionally on control of discharges from a
particular wastestream or to a single component of the environment. For example, EPA's
water pollution control activities under the National Pollutant Discharge Elimination System
(NPDES) focus on controlling point source discharges to a single medium: the Nation's
surface waters. Similarly, Agency programs under the Clean Air Act address emissions that
i , • , ..
cause or contribute to air pollution. •
j, , ' „ ' , ' • *
In recent years, it has become apparent that pollution control activities, including those
associated with POTWs, must be viewed from a multimedia perspective, where components
are interrelated and program activities directed at one medium are likely to affect others.
Discharges of toxic pollutants to and from POTWs affect virtually all environmental media-
surface water (and thus fisheries and drinking water), ground water, soils, air—and the
health and safety of treatment plant employees. Reduction of a pollutant in a POTWs
effluent, for example, might mean a transfer of that pollutant to sewage sludge or to the air.
i
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Therefore, to ensure a comprehensive evaluation of the National Pretreatment Program,
EPA adopted a multimedia appirbach to the study. Chapter 6, for example, discusses the
tradeoffs of various sewage sludge beneficial use and disposal practices regarding the.
ultimate fate of metals in sewage sludge. For instance, land-applied sewage sludge
decomposes slowly and may release toxic pollutants to soils, where they may leach to ground
water. Sludge incineration, on the other hand, may release toxic pollutants to the
atmosphere. These interrelationships made a multimedia approach necessary.
2.7.2 Reliance on Existing Data
A comprehensive evaluation of the National Pretreatment Program must cover the toxic
pollutants being discharged to POTWs by nondomestic dischargers, the performance of the
treatment plants that receive these discharges, and the environments that receive POTW
discharges. Given the breadth of the program, the resources and time necessary to collect
new data to perform this study would have been tremendous. Fortunately, considerable data
have already been collected on many components of the pretreatment program, and ongoing
data collection programs currently track such items as compliance with discharge limits and
pretreatment program implementation.
EPA decided, therefore, to rely on existing sources of data and information, and to
supplement them as appropriate with a limited number of case studies. The Agency decided
not to develop a statistical model of the program, engage in monitoring, or perform risk
assessments. Modeling was rejected as too theoretical and inappropriate for an unbiased
assessment of data adequacy. Monitoring was eliminated because of its expense and the
amount of time required. Risk assessment was not directly explored because of limitations in
the data necessary to perform such an analysis and preference for actual measures of program
effectiveness or environmental impacts. Instead, EPA decided to present as much actual
information on as many POTWs as possible.
The decision to rely on existing data provided the opportunity to respond to the
statutory mandate to assess "the adequacy of data on environmental impacts of toxic
industrial pollutants discharged from publicly owned treatment works." Chapter 6 provides
this assessment. Chapters 3, 4, 5, and 7 also address the adequacy of data for their
respective topics.
The choice of which pollutants to evaluate in this report reflects EPA's decision to use
existing data. EPA decided that each analysis undertaken for the report would address all
* '
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pollutants for which data were available for that analysis. EPA did not eliminate pollutants
from consideration simply because they are not among the 126 Clean Water Act priority
pollutants; nor did the Agency select a list of pollutants of concern and cany them through the
entire study, as was done for hazardous constituents in the DSS (see Chapter 1).
2.2 OVERVIEW OF DATA NEEDS
Having made these fundamental decisions concerning the overall approach to the study,
EPA established a conceptual framework to identify those data elements necessary to
complete the study and guide specific analyses. This framework, presented in Table 2-1,
includes the major components of the pretreatment program: industrial, commercial, and
domestic users discharging toxic pollutants; POTWs that receive these pollutants; and the
environments and humans affected by the discharges.
Within each component, EPA's framework identifies data needs for the technical
aspects of the study, such as' the amounts of pollutants discharged, removal efficiencies of
various treatment processes, and effects on the environment. It also identifies data needs for
the programmatic aspects of each component of the pretreatment program, such as the
regulatory status of industries, pretreatment program resources, and ambient water quality
standards.
The framework was used to identify and organize data sources and analyses for the
study. With its broad, multimedia approach, the framework highlighted possible relationships
among components and ensured that data were compiled and considered in context with other
data. The framework also provided the basis for evaluating data availability and adequacy, as
called for by Congress in Section 519.
2.3 EXISTING DATA SOURCES
In compiling existing data sources in accordance with the framework, EPA focused on
national data sources that provided the greatest coverage of study components and POTWs
and, thus, ensured the broadest assessment of the pretreatment program. Data from
significant studies, such as those described in Chapter 1, also were used in the present
study.
. ' ' • .- • '• " .1 ' • ' "•' '. ' • . • . ."' '
Tables 2-2 and 2-3 identify these national data sources and organize them according to
continuity atad longevity. Table 2-2 focuses on sources with continuous, ongoing data
collection, and Table 2-3 addresses sources based on one-time studies and surveys. The
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Table 2-1. Data Framework for Section 519 Study
Technical
Data
Objectives
Industrial and Other
Sources of Toxic
Pollutants1"
For each usen
Pollutants discharged
' f •
Amounts
(mass/concentration)
discharged at various stages
(raw, current, pretreatment
standards for existing sources
PSES])
Prevention tools, treatment
processes, and removal
efficiencies
Number of users of each type
(categorical, significant,
other) and each category
POTWs
>2,000 Pretreatment;
>13,000 Others
For each POTW:
Influents
• Pollutants
• Amount (mass/concentration)
Pollutant releases (wastestreams),
fates, and impacts throughout the
plant:
• Collection system
• Headworks.
• Unit processes '
Treatment processes and removal
efficiencies .
Effluents
• Pollutants
• Amounts (mass/concentration)
Sewage sludge
•• Pollutants
• Amounts (mass/concentration)
Receiving Environments
For each POTW:
Surface water ,
• Flow rate and pollutant
concentration
• Effects of POTW discharges
Ground water
• Pollutant concentration
recharge/discharge rates ,
- Effects of POTW
Terrestrial
• Pollutant and descriptive
data on soils and biota
• Effects of POTW
Air
• Ambient air quality
• Effects of POTW emissions
Workers
• Pollutant exposure
• Effects of POTW on
exposure '
Programmatic
Data
Objectives
Regulatory controls
• Categorical standards
• Local limits
• Monitoring requirements
Regulatory status
Program status
pretreatment program elements
• User control mechanisms
» Local limits
* Inspection of industrial users (lUs)
• Monitoring of lUs
« Enforcement
Program resources
• Information and management
• Technical skills
• Legal authority/political
environment
Environmental permit elements
(discharge limits, reporting,
monitoring, pretreatment, operational
and programmatic requirements)
• Effluent
• Air
• Sewage sludge
Compliance with permits and
standards
• Effluent - '
• Air
• Sewage sludge
Surface water
• Designated use
• Standards
• Compliance status
Ground water
• Designated use
• Standards
• Compliance status
Terrestrial
• Designated use
• Standards
• Compliance status
Air
• Standards
• Compliance status
Workers
• Standards
• Compliance status
"•Includes industrial, commercial, domestic, and other sources of toxic inputs, including at least 30,000 significant
industrial users (SIUs). ,
" -.' ''.'•' . ... 2-5 '
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tables describe in some detail those characteristics essential for appropriate use and
evaluation of data, including how and why data were compiled, the sources of data, and the
media and pollutants covered. The paragraphs below briefly describe several of the major
data sources listed in the tables and provide examples of how data from these sources were
used in this report.
-' • ' .. •<*-.''• • '
Table 2-2 begins with the Toxics Release Inventory System (TRIS), which is a
relatively new source that includes data on chemicals discharged and treatment and
minimization practices for manufacturing facilities that handle significant quantities of specific
toxic chemicals. It is limited to facilities that have 10 or more full-time employees and that
have manufactured, processed, or otherwise used any of more than 300 chemicals in
quantities greater than specific threshold levels. Section 313 of the 1986 Emergency Planning
and Community Right-to-Know Act describes these chemicals and the threshold levels.
As discussed in Chapter 3, TRIS data supplemented the findings of the DSS in
characterizing toxic pollutant discharges from industries to POTWs. TRIS data also were
used in Chapter 7 to determine whether POTWs reported as receiving the largest amounts of
toxic pollutants were covered by the pretreatment program.
The Permit Compliance System (PCS), including the Pretreatment Permits and
Enforcement Tracking System (PPETS), is another data base used extensively in this study.
As noted in Table 2-2, PCS is the automated tracking system for the National Pollutant
Discharge Elimination System (NPDES) program that provides various data for dischargers
with NPDES permits, currently including about 15,747 POTWs. Data elements cover permit
requirements, effluent monitoring data, and compliance and enforcement status arid history.
The PPETS component of PCS contains pretreatment-related data for most local
pretreatment programs, based on annual inspections and periodic audits of programs by EPA
Regions and States. In some cases, entry of specific data elements into PCS is optional,
particularly for pretreatment-related data elements.
PCS and PPETS were used for various analyses in every chapter of this report. In
Chapter 3, for example, data on the numbers and types of industries that discharge to
POTWs (industrial users) were taken from PCS. Chapter 4 used PCS compliance data to
identify well-operated secondary treatment plants. Chapter 5 used a number of PPETS data
elements that describe pretreatment program implementation activities. Chapter 6 used
POTW effluent monitoring data from PCS to calculate instream pollutant concentrations, and
i ' '. ' . '
2-13
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Chapter 7 used both pretreatment and effluent monitoring data. Finally, Chapter 8 used PCS
data to evaluate changes that might occur as the result of adopting alternatives to current
strategies.
The NEEDS 1988 Survey File represents the most recent results of a biannual survey
of the Nation's municipal wastewater treatment plants. NEEDS '88 includes a variety of
data, analytical tools, and reporting utilities for the estimation of funds needed for the
construction of these POTWs. For the present study, it was used to characterize industrial
flow contributions to POTWs in Chapters 3 and 7, to identify treatment processes in Chapter
4, and to support the environmental impact analysis in Chapter 6.
The Domestic Sewage Study (DSS), as described in Chapter 1 and Table 2-3, was
conducted in 1985 to evaluate the impacts of wastes discharged to POTWs as a result of the
Domestic Sewage Exclusion (DSE). Similar to the present study's approach, information
was compiled from existing sources and supplemented with EPA Region, State, local, and
industrial facility data. In contrast to TRIS, described previously, the DSS focused on 165
pollutants, the vast majority of which were RCRA hazardous constituents and 67 of which
were Clean Water Act priority pollutants.
DSS data were used in most chapters of this report. In Chapter 3, for example, DSS
' '' • i1. • •' ' , ',',.,''
data on toxic pollutant discharges by specific types of industries are compared to TRIS and
other data to characterize industrial discharges to POTWs. Chapter 4 presents the
estimates of pollutant removal efficiencies provided in DSS, and Chapter 6 also uses DSS
estimates of POTW discharges to various environmental media.
In accordance with the study approach described previously, most of the data sources
described in Tables 2-2 and 2-3 provide actual rather than projected data for as many of the
study topics as possible. They also include data from EPA program offices and include the
results of significant national and regional studies.
Another aspect of EPA's study approach, integrating performance of the study with
ongoing program implementation activities, enabled EPA to make immediate use of recent
program findings and activities in various analyses. For example, EPA created new data
bases by compiling and reorganizing information previously submitted by POTWs that
describes the development of local discharge, limitations. This information was used in
Chapter 4 to characterize pollutant removal efficiencies and in Chapter 5 to evaluate POTW
i
2-14
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capability to revise pretreatment standards. The 47-POTW data base included extensive
influent and effluent monitoring data compiled from POTWs' local limits development
documents. This data base was used to characterize secondary treatment removal efficiency
in Chapter 4. Table 2-4 further describes these and other data sources that were not national
in scope but that supported various analyses in the study.
Table 2-5 describes a number of regional and other data sources that also were used
extensively. For example, the North Carolina Department of Natural Resources and
Community Development maintains a computerized data base of information for all
pretreatment programs. This data base currently includes 121 control authorities and
contains compliance monitoring data on nearly 1,000 industrial users.
2.4 USE OF MAJOR DATA SOURCES
As noted previously, most of the major data sources were designed for a specific
purpose and cover specific data elements and wastestreams, types of facilities, and other
issues. For example, the Pretreatment Audit Summary System (see Table 2-2) stores and
summarizes the results of selected program audits of local pretreatment control authorities
conducted by EPA Regions and States in their oversight capacity. It reports on a wide range
of programmatic issues, such as the quality of permits, the types of local limits, adequacy of
resources, and data management capabilities.
For some analyses, using data from a single source proved adequate. Chapter 3, for
example, focused on the National Urban Runoff Program Study to characterize the pollutant
loadings in storm water and, thus, the potential inputs to combined sewer flows and POTWs.
In most cases, however, one data source did not provide all of the data elements necessary
for an analysis. For example, the analysis in Chapter 6 that determines how often POTWs
could cause exceedances of water quality criteria required data on POTW flow rates,
pollutant concentrations, and the flow of the receiving waters. The NEEDS '88 Survey
includes plant flow data and a receiving stream identifier, but does not track discharge
pollutant concentrations or receiving waters flow. PCS, on the other hand, includes pollutant
concentrations, but as with NEEDS, does not include receiving stream flow. The Stream
Gage/Flow system, in contrast, stores receiving stream flow but none of the other variables.
To take advantage of all available data, EPA established linkages among several of the
data sources. The linkages allowed data on specific POTWs in each linked data source to be
used in conjunction with data from any or all of the other linked sources. Successful linkages
• < . * "
. . '" ' 2-15 . • '
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Table 2-4. Major Data Sources Compiled Specifically for This Study
47-POTW Removal Efficiency Data Base
• Compiled from local limits development documents submitted by POTWs to EPA
Regions.
• 47 POTWs located in EPA Regions H, ffl, V, VI, VH, VET, IX, all with secondary
treatment and implementing approved local pretreatment programs.
• Includes influent and effluent data on 92 pollutants: 67 brganics, 23 inorganics, as well
as BOD and TSS.
Removal Credits Applications Data Base
• Compiled from removal credits applications submitted by POTWs to approval
authorities (States or EPA as appropriate).
• Detailed submissions from 17 POTWs and summary information from 6 other POTWs.
• Data include a discussion of the basic development procedures used, industries and
pollutants affected, summaries of the data used in development, and the resultant
removals claimed/credited.
Local Limits Data Base
• Compiled from local limits development documents submitted by POTWs to EPA
Regions.
• 57 local limits submissions, principally from EPA Regions VI and DC
• Data include procedures used hi the development of the limits, the data and
environmental criteria used to calculate the limits, and the resultant limits that were
determined from the evaluation.
200 POTW Local Limits Data
i '
• Compiled from reports prepared to document EPA Region and State oversight audits
of approved local pretreatment programs.
• Data include pollutant limits applied to industrial users by POTWs.
2-16
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Table 2-5. Other Data Sources
North Carolina Industrial Users Data Base
• Maintained by North Carolina Department of Natural Resources and Community
Development to monitor industrial discharges to POTWs.
• Industrial user monitoring data from 121 local pretreatment programs and nearly 1,000
industrial users. .
• . Data include industry permit limits, industrial effluent monitoring data, and compliance
information.
Ontario Ministry of the Environment's Municipal Industrial Strategy for Abatement
Study
• Study performed to provide POTW influent and effluent monitoring data to develop
monitoring regulations.
• Study conducted on 37 Canadian POTWs in 1987.
• Data include pollutant concentrations for influent and effluent streams at representative
locations in POTWs, including raw and treated sludge.
• Covers 144 organic pollutants, 13 metals, selenium, cyanide, and conventional
pollutants. '
National Water Quality Inventory—1988 Report to Congress
• Compiled by EPA from State reports on the extent to which their surface waters are
meeting the goals of the CWA and to recommend how the goals can be achieved.
• State reports submitted biennially since 1975.
• Report to Congress covers the following issues: total sizes of assessed water bodies
that are fully, partially, or not supporting designated beneficial uses, and those that are
threatened; major causes of use impairment; sources of pollution in those waters not
fully supporting their uses; and number of waiters adversely affected by toxic pollutants.
2-17
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were established between PCS/PPETS, the NEEDS Survey File, Pretreatment Audit
Summary System, General Accounting Office data (see Table 2-3), National Sewage Sludge
Survey data (see Table 2-3), and the local limits data base (see Table 2-4). For the water
quality exceedance analysis in Chapter 6, NEEDS Survey data (flow and reach number), PCS
data (pollutant concentration), and the Stream Flow/Gage file (receiving waters flow) were
linked. Figure 2-1 illustrates this linkage.
The same approach was used in Chapter 4 to identify well-operated secondary
treatment plants. NEEDS data for a particular POTW identified the type of treatment
processes (i.e., primary, secondary, and tertiary) used, and PCS data indicated whether the
POTW had ever been in significant noncompliance with its NPDES permit limits for
conventional pollutants.
Because the linkages among sources were imperfect (i.e., not all POTWs were
represented in any one source, and data were sometimes inadequate to allow complete
cross-matches) and because of the decision to use as much data as possible for each
analysis, the numbers of POTWs represented in any given analysis varied somewhat from
analysis to analysis. This accounts, for example, for the slightly different totals of
pretreatment (and nonpretreatment) POTWs presented in Figure 1-2 and Tables 1-1 and 1-
2; in each case, all data available in the sources cited were used.
Table 2-6 provides an overview of the use of a number of major data sources in this
study. It is organized according to data source and chapter and indicates where linked data
sources contributed to various analyses.
2.5 CASE STUDIES
EPA's final source of data for this Report to Congress was a set of case studies
conducted at three POTWs. By examining three local pretreatment programs in detail, EPA
obtained analytical data and descriptive information to complement the national data bases,
program studies, and State and local material described previously. The case studies
illustrate particular issues raised in each chapter, as well as portray in more general terms
the many facets of the National Pretreatment Program; in short, the case studies were
intended to impart a "real-world" perspective to the report.
2-18
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2-19
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Table 2-6. Uses of Data Sources
Data Source or Study
TRIS
PCS/PPETS
PASS
NEEDS '88
Stream Gage/Flow File
Reach File
OWAS1
WPCF Survey
DSS
304(m)/Studies
NURP
NSSS
40POTW
GAO Survey
LL Guidance
47POTW
RC Data Base 2
LL 200 POTW Data Base
NC Industries 3
MISA4
NWQ Inventory 5
Chapter and Form of Use (S = Singular; L = Linked)
3
S
•
•
•
•
•
•
•
L
, 4
S
•
•
•
•
L
f
T
1
5
S
•
'•
•
•
•
L
6
S
•
•
•
•
•
L
•
•
•
•
7
S
•
•
•
•
•
•
•
•
L
ff
FT
ii
•
•
1. OWAS - Office of Water Accountability System
2. RC - Removal Credits
3. NC - North Carolina
4. MISA - Municipal Industrial Strategy for Abatement
' 5. NWQ - National Water Quality
Note: Pretreatment Facility File, as referenced in Table 2-2, was used primarily
to identify pretreatment facilities for the above sources.
* 2-20
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In selecting POTWs for case studies, EPA did not seek out and analyze "perfect"
programs. Because of the small number of case studies to be performed, EPA selected a
group of POTWs that would:
• Exhibit as much diversity as possible in geographical location, size, industrial
makeup, and basis of pretreatment standards
,• Yield data on industrial users, wastestreams, and receiving media with sufficient
quality, breadth, and depth to provide illustrations of the topics of concern in the
report
• Meet with the approval of EPA Headquarters, EPA Region and State pretreatment
coordinators, and POTW personnel and not compromise any current or planned
enforcement initiatives. -
EPA selected the following three POTWs as case studies:
• Thomasville, North Carolina—A small (3 million gallons per day [mgd]) POTW
serving a population of 16,000. Thomasville's four categorical industrial users (CIUs)
and nine other significant industrial users (SIUs [primarily furniture manufacturers
and textile mills]) contribute 25 percent of the POTW's average flow.
• Hampton Roads Sanitation District (HRSD), Virginia—A large metropolitan POTW
(total 203 mgd) with 10 treatment plants serving the Tidewater area of southeastern
Virginia. HRSD accepts wastewaters from about 260 SIUs, 35 of which are CIUs.
Industrial wastewaters—mostly from electroplaters, organic chemical manufacturers,
and 10 major military installations—constitute 10 percent of the flow to HRSD's
treatment plants.
• Pocatello, Idaho—A medium-sized (12 mgd design flow rate, 7 mgd average) POTW
that serves a population of 50,000 in the cities of Pocatello and Chubbuck. Two
industries subject to categorical standards discharge to the POTW, as do seven other
significant industries and 75 additional nonsignificant users (including commercial
use, hospitals, and a university). Approximately 20 percent of the POTWs average
daily flow is contributed by nondomestic users. ,
Table 2-7 lists general characteristics of the three case study POTWs.
2-21
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Table 2-7. General Characteristics of Case Study Cities
City/POTW
Design Total
Flow Population
(mgd) Served
Jurisdictions
Economic Base
Thomasville, NC,
Hamby Creek
Hampton Roads
Sanitation District,
VA (10 plants)
4.0
16,000 City of Thomasville Manufacturing Service
203 1,255,370
(all (1988 est.)
plants
total)
Pocatello, ID
12.0
50,000
Chesapeake
Hampton
Newport News
Norfolk
Poquoson
Portsmouth
Suffolk
Virginia Beach
Williamsburg
Gloucester County
Isle of Wight County
James City County
York County
City of Pocatello
CityofChubbuck
Military Installations
and Related Indus-
tries; Service and
Resort Sectors
Transportation
Chemical
Manufacturing and
Food Processing
2-22
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REFERENCES
U.S. Environmental Protection Agency. 1991. Supplemental Manual on the Development and
Implementation of Local Discharge Limitations Under the Pretreatment Program.
Washington, DG: Office of Water Enforcement and Permits.
U.S. EPA. 1987. .Guidance Manual on the Development and Implementation of Local
Discharge Limitations. Washington, DC: Office of Water Enforcement and Permits.
U.S. EPA. 1986a. Pretreatment Compliance Inspection and Audit Manual for Approval
Authorities. Washington, DC: Office of Water Enforcement and Permits.
"••.'" • • •' t, ' • , '
U.S. EPA. 1986b. Report to Congress on the Discharge of Hazardous Wastes to Publicly
Owned Treatment Works. Washington, DC: Office of Water Regulations and
Standards. EPA 530-SW-86-004.
U:S.EPA. 1983. Results of the Nationwide Urban Runoff Program. Volume 1-Final Report,
Washington, DC: Water Planning Division. NTIS: PB84-185552.
U.S. EPA. 1982. Fate of Priority Pollutants in Publicly Owned Treatment Works—Final
Report. Washington, DC: Office of Water Regulations and Standards, Effluent
Guidelines Division. EPA 440/1-82/303.
U.S. General Accounting Office. 1989. Improved Monitoring and Enforcement Needed for
Toxic Pollutants Entering Sewers. GAO/RCED-89-101.
2-23
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3. DISCHARGE OF TOXIC POLLUTANTS TO POTWs .
This chapter identifies the toxic pollutants1 discharged to publicly owned treatment
works (POTWs) and the sources responsible for these discharges. Although not specifically
requested by Congress under Section 519 of the 1987 Water Quality Act, the identification of
the types and sources of toxic pollutants discharged to POTWs is a necessary step toward
evaluating the adequacy of controls on toxic pollutant discharges, their treatability and fate
•' ' . ' . . - ' '
within POTWs, and their environmental impacts.
Virtually all chemicals used by industrial, commercial, and domestic customers may be
discharged to POTWs and are subject to varying degrees of regulatory control. This chapter
characterizes the sources and types of toxic pollutants discharged to POTWs from.industrial/
commercial, domestic, and other sources (Sections 3.2 through 3.4, respectively) and the
regulatory controls that may affect these discharges. It concludes with an overview of how
pollution prevention initiatives may lower the discharge of toxic pollutants to POTWs;
3.1 METHODOLOGY
Over the past several years, the U.S. Environmental Protection Agency (EPA) has
conducted several major studies to estimate the types and quantities of toxic pollutants
discharged to POTWs, as well as to evaluate the effectiveness of regulatory controls on the
discharge of these pollutants. In this Report to Congress, EPA used these previous studies,
expanding the Coverage of toxic pollutants and the examination of the sources of these
pollutants. •
3.1.1 Previous EPA Studies
In 1981, the Regulatory Impact Analysis (RIA) for the General Pretreatment
Regulations (40 CFR Part 403) estimated the quantities of priority pollutants discharged to
POTWs from 22 industrial categories subject to national categorical standards. The RIA
estimated that categorical industrial dischargers to POTWs are responsible for the
generation of about 460 million pounds (approximately 208,000 metric tons) per year of
metals and organics in raw (i.e., untreated) wastewater (EPA, 1981). Assuming full
compliance with applicable categorical standards, EPA estimated that industrial contributions
1. "Toxic pollutant" is defined to include the CWA "priority" pollutants (Appendix A of
40 CFR Part 423 and listed in Figure 3-1 of this report) and other "nonpriority" pollutants
as reported by the various data sources used in this chapter. .
*
3-1
-------
to POTWs would be reduced by approximately 85 percent to about 70 million pounds
(approximately 31,750 metric tons) per year of metal and organic wastes.
In 1985, the EPA Report to Congress on the Discharge of Hazardous Wastes to Publicly
Owned Treatment Works (EPA, 1986b, referred to as the Domestic Sewage Study and
hereafter as the DSS) estimated that approximately 160,000 industrial and commercial
facilities discharge 3,200 million gallons per day (mgd) of process wastewater to POTWs (or
approximately 12 percent of total POTW flow). This estimate represents actual flows as
opposed to NEEDS .estimates of POTW design flows discussed in Subsection 1.1.4.
Estimates for those industrial categories subject to national categorical standards were 136
million pounds (62,000 metric tons) per year of hazardous metal pollutants and approximately
99 million pounds (45,000 metric tons) per year of hazardous organic pollutants at raw
(untreated) discharge levels. Assuming full compliance with categorical standards, EPA
estimated that hazardous metal pollutants discharged to POTWs from categorical industries
would be reduced by approximately 95 percent to about 7 million pounds (3,300 metric tons)
per year, and hazardous organic pollutants discharged to POTWs would be reduced by
approximately 55 percent to about 44 million pounds (20,000 metric tons) per year.
3.1.2 Approach to Identifying Sources and Types ofTojdc Pollutants
This chapter examines more sources of discharges and pollutants than did the
Pretreatment RIA or the DSS. The RIA primarily evaluated discharges of the 126 Clean
Water Act (CWA) priority pollutants from 22 categorical industries. The DSS went beyond
this to evaluate 165 hazardous constituents (including 67 priority pollutants) from categorical
and noncategorical industries (including commercial facilities).
Sources of Discharges; Whereas the emphasis of previous studies was on industries
subject to national categorical pretreatment standards, due partly to the availability of data
for such industries, data collection and analysis activities for this Report to Congress have
also focused on toxic pollutants from noncategorical industrial facilities (including commercial
facilities) and from domestic and other sources.
i ' ' l; - ' i . . '
Pollutants. The Pretreatment RIA. focused primarily on the priority pollutants, largely
because those pollutants were specifically regulated under the CWA. Because the intent of
the DSS was to investigate discharges of hazardous wastes to sewers, the DSS
concentrated on 165 hazardous pollutants that are indicators of Resource Conservation and
Recovery Act (RCRA) hazardous waste; it too, however, stressed the priority pollutants—
•w ,' , „ - • '!' , , " ' ' .,''''.'•'
' * ' '• '
. 3-2 ' ; ' " ' :' ' ;
-------
again for reasons of data availability. This Report to Congress is not limited to a particular
subset of "pollutants. Instead, the approach was to identify the broadest possible universe of
toxic pollutants, including priority pollutants and the RCRA hazardous constituents, from
various sources. ,
*.
3.1.3 Data Sources •',.'•'
EPA collected and analyzed information from a variety of sources to identify all possible
toxic pollutants discharged to POTWs. Figure 3-1 provides a listing of the 126 priority
pollutants. The primary information sources were national data bases and studies generated
and maintained by EPA. Other sources, such as State data bases, were used to supplement
national data as necessary. No sampling or analysis of possible sources of toxic .pollutants
was performed specifically for mis report.
At the national level, the Industrial Technology Division (TTD) of EPA's Office of Water
Regulations.and Standards recently completed several studies in which data were collected
regarding discharges from a variety of industrial categories for which EPA is considering
.revising or promulgating national categorical pretreatment standards. The EPA Office of
Water Enforcement and Permits (OWEP) has also collected State and local data to assist
control authorities in regulating commercial sources of toxic pollutants through the
development and refinement of local limits.
In addition to the above data collection activities conducted within the Office of Water,
EPA's Toxics Release Inventory System (TRIS) was ,used as a source of information
regarding toxic pollutant discharges to POTWs. As discussed in Chapter 2, TRIS contains
information collected pursuant to Section 313 of the Emergency Planning and Community
Right-to-Know Act of 1986, which requires certain industrial and commercial facilities to
submit annual reports regarding releases of particular toxic chemicals to the environment,
including POTWs. Although limited in its coverage of facilities, TRIS contains information
regarding the quantities of more than 300 toxic chemicals released to POTWs.
Most, State agencies responsible for pretreatment program oversight and
implementation maintain information regarding the numbers and types of industrial and
commercial facilities that discharge to POTWs. Several State agencies maintain data bases
that contain readily available information regarding the types of toxic pollutants being
discharged to POTWs. One such data base, maintained by the State of North Carolina,
contains monitoring data for all indirect discharges regulated by control authorities in the
State. This data base, which is useful as a benchmark for data adequacy because it provides
'• • 3-3 . ' •"'":'''• •'.
-------
Figure 3-1. Priority Pollutants
Acrolein
Benzene
Carbon Tetrachloride
Chlorodibromomethane
2-Chloroethylvinyl Ether
Dichlorobromomethane
1,2-Dichloroethane
1,2-DicMoropropane
Ethylbenzene
Methyl Chloride
1,1,2;2-Tetrachloroethane
Toluene
1,1,1-Trichloroethane
Trichloroethylene
Chlorophenol
2,4-Dimethylphenol
2,4-Dinitrophenol
4-Nitrophenol
Pentachlorophenol
2,4,6-Trichlorophenol
Volatile Compounds
Vinyl Chloride
Acrylonitrile
Bromoform
Chlorobenzene
Chloroethane
Chloroform
1,1-Dichloroethane
1,1-Dichloroethylene
1,3-Dichloroprbpylene
Methyl Bromide
Methylene Chloride
Tetrachloroethylene
1,2-Trans-Dichloroethy lene
1,1,2-Trichloroethane
Acid Compounds '.
2,4-Dichlorophenol
4,6-Dinitro-O-Cresol
2-Nitrophenol
P-Chloto-M-Cresol
Phenol
Base/Neutral Compounds
Acenaphthene
Anthracene
Benzo(a)Anthracene
Benzo(b)Fluoranthene
Benzo(k)Fluoranthene
Bis(2-Chloroethyl)Ether
Bis(2-Ethylhexyl)Phthalate
Butyl Benzyl Phthalate
4-Chlorophenyl Phenyl Ether
Dibenzo(a,h)Anthracene
1,3-Dichlorobenzene
3,3-Dichlorobenzidine
Dimethyl Phthalate
2,4-Dinithrotoluene
Di-N-Octyl Phthalate
Fluoranthene
Fluorene
Hexachlorobutadiene
Hexachloroethane
Isophorone
Nitrobenzene
N-Nitrosodi-N-Propylamine
Phenanthrene
Acenaphthylene
Benzidine
Benzo(a)Pyrene
Benzo(ghi)Perylene
Bis(2-Chloroethoxy)Methane
Bis(2-Chlorpisopropyl)Ether
4-Bromophenyl Phenyl Ether
2-Chloronaphthalene
Chrysene
1,2-Dichlorobenzene
1,4-Dichlorobenzene
Diethyl Phthalate
Di-N-Butyl Phthalate
2,6-Dinitrotoluene
1,2-Diphenylhydrazine (as Azobenzene)
Hexachlorobenzene
Hexachlorocyclbpentadien
Indeno( 1,2,3-cd)Pyrene
Naphthalene
N-Nitrosodimethylamine
N-Nitrosodiphenylamine
Pyrene
1,2,4-Trichlorobenzene
3-4
-------
Figure 3-1. Priority Pollutants (continued)
Pesticides and PCBs
Aldrin Gamma-BHC
Alpha-BHC Delta-BHC
Beta-BHC Chlordane
4,4'DDT 4,4'-DDE
4,4'-ODD Dieldrin
Alpha-endosulfan Beta-Endosulfan
Endosulfan Sulfate Endrin
Endrin Aldehyde Heptachlor
Heptachlor Epoxide PCB-1242
PCB-1254 PCB-1221
PCB-1232 PCB-1248
PGB-1260 PCB-1016
Toxaphene
Metals and Cyanide
Antimony Arsenic
Beryllium Cadmium
Chromium Copper
Lead Mercury
Nickel Selenium
Silver Thallium
Zinc Cyanide
Miscellaneous
2,3,7,8-Tetrachlorodibenzo-P-Dioxin (TCDD)
Asbestos
Source: 40 CFR Part 423 Appendix A.
3-5
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some of the best State data, was used to provide additional data for this report regarding the
types and levels of toxic pollutants being discharged to POTWs.
3.2 INDUSTRIAL AND COMMERCIAL SOURCES OF toxic POLLUTANTS
This section describes toxic pollutants discharged to POTWs from industrial and
commercial sources. Subsection 3.2.1 describes the relative extent of industrial/commercial
discharges to POTWs in two ways: the number of industrial/commercial users discharging to
POTWs and the relative volume .of wastewater discharged by industrial/commercial users as
compared to total POTW wastewater flow. Subsection 3.2.2 then identifies the toxic
pollutants discharged to POTWs from industrial and commercial sources.
3.2.1 Estimates of the Number of and Flow From Industrial and Commercial
Dischargers
The types and quantities of toxic pollutants discharged to POTWs depend in part on the
number of industrial and commercial users arid the total flow from these .users relative to the
total POTW flow. This subsection estimates the number of industrial and commercial
dischargers to POTWs (Subsection 3.2.2.1) and describes what portion of total POTW flow
consists of industrial and commercial flow (Subsection 3.2.2.2).
3.2.1.1 Estimates of Industrial and Commercial Users
Under the National Pretreatment Program, industrial and commercial facilities that
discharge to POTWs typically are classified in three ways:
• Categorical Industrial User (CIUV—An industrial facility subject to regulation by
technology-based categorical pretreatment standards established by EPA.
• Significant Industrial User (SIUI—Defined by EPA as all categorical industrial users,
noncategorical industrial users with an average process flow of 25,000 gallons per
day or more, noncategorical industrial users contributing 5 percent or more of the
POTWs dry weather hydraulic or organic capacity, or any industrial user designated
by the control authority to have a reasonable potential to affect POTW operations
adversely.
% Other Nonsignificant User—Defined as any other nondomestic source that is not an
SIU but may still be regulated by a local pretreatment program. These users are
typically surcharged for sewer use, inspected, and/or controlled through a sewer use
permit (Lie., regulated by a POTW).
Data Sources
Several data sources estimate the total number of CIUs and SIUs that discharge to
; f "', 1 , , , , ,•'••', " ,'.,'"' • "|l"
POTWs. These data sources, described in Chapter 2, include the EPA Permit Compliance
i ' ' • : • . ' . .. " '
3-6 ' ' ' ' ' .'• ' :
-------
System (PCS), which includes the Pretreatment Permits and Enforcement Tracking System
(PPETS); the EPA Pretreatment Audit Summary System (PASS); the EPA National Sewage
Sludge Survey (NSSS); and the Office of Water Accountability System (OWAS). '
Analysis of these data sources revealed that PCS/PPETS was the most comprehensive
source for estimates of the number of CIUs and SIUs discharging to POTWs.2 PCS/PPETS
contained SIU data for 9Q percent of approved local pretreatment programs, many State-
operated pretreatment programs, and a number of POTWs regulated outside of State and
local pretreatment programs.
• ( i • '•-'., r '
To establish comprehensive national estimates of the numbers of CIUs and SIUs, EPA
first extracted available information from the PCS/PPETS system. The Agency used PASS
and NSSS in the absence of PCS/PPETS data for locally run programs3 and OWAS in the
absence of PCS/PPETS data for industrial users regulated by approval authorities.4
As for other nonsignificant regulated users (i.e., non-CIU and non-SIU), no national
estimates exist. The only EPA data source containing information regarding other regulated
users is PASS. PASS has estimates for other regulated users for just over 400 POTWs with
approved pretreatment programs.
Estimates of CIUs and SIUs
Table 3-1 summarizes CIUs and SIUs by State. Appendix A-1 lists by State the
number of CIUs and SIUs for each POTW with an approved pretreatment program. Each
2. Most data were provided by PCS (1,356 POTW control authorities) and supplemented by
PASS for 31 control authorities and by NSSS for 9 additional control authorities.
3. No CIU and SIU data were available in any of the data bases for 102 control authorities
with approved local programs. It should also be noted that for one of the nine control
authorities for which NSSS data were used, the number of CIUs was not available.
4. OWAS was used in the absence of PCS data for industrial users regulated by approval
authorities. It should be noted that data regarding numbers of CIUs and SIUs regulated
by approval authorities (i.e., in the absence of a local POTW or State-approved program)
were not available for 19 of the 50 States or for the District of Columbia and Puerto Rico.
3-7
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approved pretreatment program is reflected in the "status" column in Appendix A-l by "@".
As shown, over 30,000 SIUs are either regulated by approved local pretreatment programs or
regulated directly by approval authorities (EPA or an approved State). Because over 60
percent of these industrial users are noncategorical SIUs, control authorities are regulating a
greater percentage of industrial users not subject to national effluent regulations (i.e.,
categorical pretreatment standards).
As indicated in Table 3-1, most CIUs and SIUs (over 90 percent) are regulated under
approved local pretreatment programs. Table 3-1 indicates that more than #00 CIUs and over
200 SIUs are regulated by approval authorities (approved State or EPA) in the absence of
approved POTW pretreatment programs. However, the estimates in Table 3-1 for
discharges to nonpretreatment POTWs are probably low because estimates of the number of
i • / ..... . •• . „ ••.,.,',,
CIUs and SIUs discharging to nonpretreatment POTWs were not available for several States.
Estimates of Nonsignificant Industrial/Commercial Users
Comprehensive national estimates are not available for nonsignificant industrial users
regulated by local pretreatment programs. However, estimates of the number of
nonsignificant industrial users were available for 437 out of me 530 POTWs contained in
PASS. EPA estimates that more than 35,000. other industrial users are regulated by those
437 approved POTW pretreatment programs alone. This indicates that the total number of
nonsignificant industrial users for this subset of POTW pretreatment programs is greater
than the estimated total number of SIUs estimated for the universe of State and POTW
pretreatment programs. However, characterization data regarding these nonsignificant
industrial users are limited. Therefore, it is unclear whether these other industrial users
classified as nonsignificant could be sources of toxic pollutants.
-.._.,. ; . i ,• .; . , '• • . ...••',
The Association of Metropolitan Sewerage Agencies (AMSA) recently provided
estimates of the number of nonsignificant industrial users regulated by its members (AMSA,
1990). Based on its survey, 82 POTW control authorities regulated almost 45,000
nonsignificant industrial users. This total represented more than 80 percent of all regulated
industrial users estimated by the survey. These two data sources suggest that there may be
several hundred thousand nonsignificant industrial users nationally.
' • • j , '• '; • ' ' ' ' '' , ' . .' !',
• ••'••' j '•,'," .; ':,; ;•;;: ••' '..•' .•••,• ". , ;'•'-.
3.2.1.2 Estimates of Industrial and Commercial Flow Contributions
Analysis of the total contribution of flow from industrial and commercial users can
indicate, in part, the potential quantities of toxic pollutants that could be discharged to
3-12
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POTWs. If, for example, a large percentage of a POTW's total flow is from industrial and
commercial sources, or if a POTW has a large number of industrial and commercial users, it is
more likely that significant amounts of toxic pollutants are being received by the POTW. This
section describes the contribution of flows to POTWs from industrial and commercial sources.
Data Sources
The primary source used to gather POTW and industrial flow data is the NEEDS '88
data base, which has flow data for over 90 percent of the POTWs. As discussed in Chapter
2, the NEEDS data base contains a variety of information regarding POTW operations.
These data are used by EPA to determine construction costs for POTWs and to estimate
costs for future municipal wastewater treatment needs. In the absence of flow data for a
POTW in NEEDS, EPA used several data sources to estimate POTW flow data, including
PASS (for 63 POTWs), PCS (1 POTW), and the NSSS (1 POTW). Flow data for POTWs
that are not control authorities (i.e., POTWs whose industrial users are regulated by State
control authorities or approval authorities) were derived from the NEEDS data base
exclusively.
.POTW Flow Estimates
Appendix A-2 presents the total design, total actual, and total industrial flow rates for
each of the 1,994 POTWs that are part of local pretreatment programs and for which data
were available. Each POTW with an approved pretreatment program is reflected in the
"status" column of Appendix-A-2 by "@". POTWs with a "c" in the "status" column are
covered under the POTW's approved program with the same CANPDES number. Table 3-2
summarizes the distribution of industrial flows over the distribution of flow rates at POTWs
with pretreatment programs (i.e., POTWs that are control authorities). Using the data given,
it is estimated that over 3.6 billion gallons of industrial wastewater are discharged to these
POTWs each day. Overall, this accounts for just over 15 percent of the total actual flow to
POTWs; total actual POTW flow is estimated to be approximately 21 billion gallons per day.
Industrial flows constitute less than 25 percent of the total flow for almost 70 percent of the
POTW control authorities. However, for 108 POTW control authorities, all with total actual
POTW flows of less than 50 mgd, industrial flows account for more than 50 percent of the.
total POTW flow.
Drawing upon information given in the NEEDS data base, EPA estimated that the
discharge from POTWs that are not required to have local pretreatment programs (excluding
3-13
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Table 3-2. Percent Industrial Flow by POTW Average Daily Flow Rate
POTW
Average
Daily Flow
Rate (mgd)*
0< - £0.5
Total How (mgd)
Industrial How
(mgd)
Percent Industrial How •
0£ - £25
26.62
1.13
25< - £50
8.04
2.98
50< -*£75
2.54
1.66
75< - <100
,1.23
1.08
Number of Control
•
0.5< - £1.0
Authorities
Total How (mgd)
Industrial How
(mgd)
,100
65.55
4.17
. 27
21.97
7.88
7
4.29
2.73
4
6.17
5.47
Number of Control
1.0< - £5.0
Authorities
Total How (mgd)
Industrial How
(mgd)
84
1,073.40
90.11
28
261.65
93.17
6
113.22
69.18
7
20.15
17.20
Number of Control .
5.0<- £10.0
Authorities
Total How (mgd)
Industrial How
(mgd)
397
1,333.19
111.34
108
279.23
103.77
40
86.84
51.75
10 J
26.50 m
23.84 T
Number of Control
10.0< - £25.0
Authorities
Total How (mgd)
Industrial How
(mgd)
187
1,865.81
166.00
40
749i42
268.48
12
163.29
105.35
4
0.00
0.00
Number of Control
25.0< - £50.0
Authorities
Total How (mgd)
Industrial How
(mgd)
123
1,894.43
175/71
46
407.50
142.69
10
203.05
117.05
0
65.94
57.95
Number of Control
50< - £100.0
Authorities
Total How (mgd)
Industrial How
(mgd)
55
1,381.09
173.63
12
720.92
270.56
6
0.00
0.00
2
0.00
0.00
Number of Control
•
Authorities
19
10
0
0
I
3-14
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Table 3-2. Percent Industrial Flow by POTW Average Daily Flow Rate
(continued)
POTW
Average , .
Daily Flow
Rate (mgd)*
>100
No Data
Percent Industrial Flow
0<-<25
Total Flow (mgd) 9,209.57
Industrial Flow (mgd) 1,160.46
Number of Control
Authorities 31
Total Flow (mgd) 0.00
Industrial Flow (mgd) 0.00
Number of Control
Authorities 53
25<-<50 50<-<75 75< - <100
1,374.03 0.00 0.00
434.06 0.00 0.00
6 0 0
- ' . '
Total How = 21,365.64 mgd
Total Industrial Flow = 3,659.40 mgd
Total Number of Control Authorities = 1*434
Source: NEEDS '88, PCS, PASS, NSSS.
*A control authority may comprise more than one wastewater treatment plant or POTW. This table
covers POTW control authorities and not POTWs where EPA or the State is the control authority.
3-15
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POTWs in 403.10 [e] States), and for which data exist, is approximately 6 billion gallons per
day.5 The industrial/commercial contributions make up less than 10 percent of the total flow
of POTWs that are not control authorities.
Table 3-3 summarizes the number of SIUs according to ranges of total average daily
flow rates for POTW control authorities. As indicated, the average number of SIUs per
control authority increases with increasing control authority flow rate. Seventy-four percent
of all control authorities have total actual flow rates of 10 mgd or less and regulate an average
of approximately 10 SIUs, including an average of 3 CIUs, or less.
3.2.2 Industrial and Commercial Sources
This subsection describes the toxic pollutants discharged to POTWs by industrial and
commercial sources. The three primary data sources evaluated in this section are the DSS,
TRIS, and ITD's 304(m) studies.
3.2.2.1 Industrial Categorization Scheme
The initial step in describing the toxic pollutants discharged by industrial and
commercial sources was to organize these sources into specific categories to facilitate
comparison among the various data sources. This subsection adopted the industrial
categorization scheme used in the DSS (see Table 3-4). The DSS profiled discharge
practices and presented data for 47 different industrial categories. The DSS categorization
scheme was based on the grouping of industrial/commercial facilities with comparable
wastewater characteristics. The benefit of using the DSS categorization scheme is that it
allows direct comparison between new data collected for this report and the data given in the
DSS.
Consent Decree Industrial Categories „
The 47 industrial categories shown in Table 3-4 include the traditional Natural
Resources Defense Council (NRDC) Consent Decree (or categorical) industries. Many of
these categories correspond well with the industrial categories for which effluent limitations
guidelines and standards have been developed or proposed. In some cases, Consent Decree
5. It should be noted that this number represents data for only a portion of the universe of
POTWs that are not required to have local pretreatment programs. The actual total flow
from all such POTWs is larger.
3-16
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3-17
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Table 3-4. Industrial Categories as Profiled in the EPA Domestic Sewage Study
Adhesives and Sealants*
Battery Manufacturing*
Coal, OH, Petroleum Products, and Refining*
Construction Industry (contract and special trade)
Cosmetics, Fragrances, Flavors, and Food Additives
Dye Manufacture and Formulation*
Electric Generating Power Plants and Electric Distribution Services
Electrical and Electronic Components*
Electroplating/Metal Finishing*
Equipment Manufacture and Assembly*
Explosives Manufacture*
Fertilizer Manufacture
Food and Food By-Products Processing
Gum and Wood Chemicals, Varnishes, Lacquers, and Related Oils*
Hazardous Waste Site Cleanup
Industrial and Commercial Laundries*
Ink Manufacture and Formulation*
Inorganic Chemicals Manufacturing*
Iron and Steel Manufacturing and Forming* 4
Laboratories and Hospitals
Leather Tanning and Finishing*.
Miscellaneous Chemical Formulation
Motor Vehicle Services
Nonferrous Metals Forming*
Nonferrous Metals Manufacturing*
Organic Chemicals Manufacturing*
Paint Manufacture and Formulation*
Pesticides Formulation*
Pesticides Manufacturing*
Pharmaceutical Manufacturing*
Photographic Chemicals and Film Manufacturing*
Plastics Molding and Forming* .
Plastics, Resins, and Synthetic Fibers Manufacturing*
Porcelain Enameling*
Printing and Publishing*
Pulp and Paper Mills*
Rubber Manufacture and Processing*
Service Related Industries (other than motor vehicle services)
Soap and Detergents, Cleaning Preparations, and Waxes Manufacture and Formulation
Stone, Clay, Glass, Concrete, and Other Mineral Products
Textile Mills*
Timber Products Processing*
Transportation Services
Waste Reclamation Services
Waste Treatment and Disposal Services
Wholesale and Retail Trade
Wood Furniture Manufacture and Refinishing
*Industrial category that falls within the scope of the NRDC Consent Decree.
Source: EPA (1986).
3-18
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industrial categories were subdivided or combined for purposes of the DSS. Specifically, the
modifications to the consent decree industrial categories include:
• Expanding the petroleum refining category to include production of coal and oil
products and renaming the category coal, oil, petroleum-products, and refining.
• Combining the coil coating category with the electroplating/metal finishing category
because of the similarity of their processes.
• Combining the aluminum, copper, and nonferrous metals forming categories into one
category entitled nonferrous metals forming.
• Dividing the metals molding and casting category into its ferrous and nonferrous
subcategories. The nonferrous metals subcategories were included in the nonferrous
metals forming category and the ferrous metals subcategories were included in the
iron and steel manufacturing and forming category.
• Dividing the organic chemicals, plastics, and synthetic fibers category into three
categories: dye manufacture and formulation; organic chemicals manufacturing; and
plastics, resins, and synthetic fibers manufacturing categories.
• Including the photographic processing category in the service-related industries
category. : :
• Moving the car wash subeategory from the auto and other laundries category to the
motor vehicle services category and addressing laundries as a separate Category
entitled industrial and commercial laundries. ;
• Expanding the electroplating/metal finishing category to include other metal'
fabrication and metal products manufacturing processes.
i Expanding the leather tanning and finishing and pulp and paper categories to include
. processing of the finished product .
Other Industrial Categories
Table 3-4 includes 17 categories of smaller service-oriented industries that do not fall
within the scope of the NRDC Consent Decree, either because they have emerged in
importance since negotiation of the Consent Decree (e.g., waste reclamation services, waste
treatment and disposal .services) or because of their smaller size and service-related
orientation (e.g., motor vehicle services, service-related industries, and laboratories and
hospitals). As a result, most of these industrial categories have never been reviewed
extensively for regulatory purposes until recently.
3.2.2.2 Domestic Sewage Study • /
This subsection summarizes the findings of the DSS as they relate to the types and
sources of toxic pollutants discharged to POTWs. Loadings presented in the DSS were
derived primarily from .data collected by the EPA Office of Water Regulations and Standards,
3-19
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ITD, in support of the development of effluent limitations guidelines and standards. In
addition, the EPA Office of Solid Waste Industry Studies Data Base (ISDB) provided
.discharge estimates for many nonpriority toxic pollutants discharged by the organic chemicals
industry (i.e., dye manufacture and formulation, organic chemicals manufacturing, pesticides
manufacturing, and plastics, resins, and synthetic fibers manufacturing).
Pollutant loadings were estimated in the DSS under three discharge scenarios:
• . • •. •' ' ' • ,. ^ ' '• ' ',-' '. V". '•••'.. '•'. ' ''it '••''•' , '•• , ! ;:f:' • '.'••'•:" "';,:': .:
• Raw Discharge—Represents loadings of pollutants in wastewater assuming no
pretreatment is provided.
• Current Discharge—Represents loadings of pollutants in wastewater at "current"
treatment levels. For most industrial categories, "current" levels of treatment
represent levels present before promulgation of the categorical Pretreatment
Standards for Existing Sources (PSES).
• After-PSES—Represents loadings of pollutants in wastewater at treatment levels
required to meet, proposed and promulgated categorical PSES limitations. This
scenario assumed full compliance with'categorical pretreatment standards by all
industrial facilities. After-PSES loadings for those industrial categories for which
PSES limitations have not been promulgated reflect current loadings for those
industrial categories (i.e., some degree of treatment of raw loadings is provided).
limitations of the Domestic Sewage Study
Although the DSS involved the most comprehensive evaluation of industrial and
commercial discharges of toxic pollutants to POTWs to date, several limitations were
associated with the study:
* The DSS examined 165 hazardous pollutants, of which only 67 were CWA priority
pollutants. In part, these 165 hazardous pollutants were selected to represent those
hazardous wastes most likely to be discharged to POTWs and those for which
discharge data were most likely available. 'Therefore, not all toxic pollutants
• discharged to POTWs may have been identified or examined.
• Estimates of national loadings of toxic pollutants to POTWs were available only for
Consent Decree industrial categories. This is primarily because most loadings were
based on data collected by ITD in support of categorical standards development.
• Except for the organic chemicals industrial categories, discharge data needed to
calculate loadings consisted primarily of priority pollutant data. Estimates of
industrial loadings for several industrial categories were also based on older (i.e.,
pre-1980) data. The characteristic operations for industrial categories may have
since changed.
3-20
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Toxic Metal Pollutant Loadings From Consent Decree Industrial Categories
Of the 165 hazardous pollutants used to represent hazardous wastes discharged to
POTWs, 13 toxic metal pollutants were identified as being discharged to POTWs by at least
one of the DSS industrial categories shown in Table 3-4. Appendix A-3 lists the quantity of
each toxic pollutant discharged under the raw loadings, current, and after-PSES scenarios for
each DSS industrial category. Table 3-5 summarizes the total loadings of toxic metals and
cyanide under the raw and after-PSES scenarios described previously for each Consent
Decree industrial category. .
Table 3-5 indicates that approximately 204 to 218 million pounds per year of toxic metal
pollutants are discharged to POTVVs under the raw discharge scenario. Raw loadings of toxic
metal pollutants for the Consent Decree industries are estimated to be reduced by
approximately 94 percent after implementation of PSES for the applicable industrial
categories, assuming full compliance by all industries. This reduction results in annual PSES
loadings for toxic metal pollutants of about 13 to 14 million pounds.
The electroplating/metal finishing industrial category is the major source of priority toxic
metals under the after-PSES scenario. Other major sources under the after-PSES scenario
include the industrial .and commercial laundries;6 coal, oil, and petroleum products and
refining; organic chemicals manufacturing; and pulp and paper industrial categories.
Toxic Organic Pollutant Loadings From Consent Decree Industrial Categories .
Of the 165 hazardous pollutants representing the hazardous wastes being discharged to
POTWs, over 100 toxic organic pollutants were identified as being discharged to POTWs by
at least one of the Consent; Decree industrial categories. Table 3-5 identifies the total
loadings of toxic organics under the raw and after-PSES discharge scenarios described above
for each of the Consent Decree industrial categories. Between 82 and 254 million pounds per
year are estimated to be discharged to POTWs under the raw discharge scenario from all the
Consent Decree industrial categories.7 It was estimated that these toxic organic pollutant
raw loadings are reduced overall by approximately 47 to 80 percent after the implementation
6. Note that PSES has not yet been promulgated for this category.
7. . The range in estimates is attributable to differences in estimates between the Office of
Water ITD and the Office of Solid Waste ISDB data bases, which are due to the
difference in methodologies used to derive national estimates in each data base.
3-21
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of categorical pretreatment standards by applicable industrial categories. The total toxic
organic pollutant loadings after PSES were estimated between 43 and 51 million pounds per
• year (19,000-23,000 metric tons per year). .
' , ' .• - .' 'f ' • •• • •, Hi,,
As shown in Table 3-5, several industrial categories contribute significant quantities of
toxic organics to POTWs under the raw discharge scenario. Data from ITD indicate that
these categories include _ equipment manufacture and assembly; organic chemicals
manufacture; pharmaceutical manufacture; electroplating/metal finishing; pesticides; and
plastics, resins, and synthetic fibers manufacturing. The source profile for loadings of toxic
organic pollutants changes significantly after PSES implementation to exclude those
•industrial categories regulated under categorical'standards for priority organics. After PSES
implementation, major sources of toxic organic pollutants include equipment manufacture;
pharmaceutical manufacture; coal, oil, petroleum products and refining; and industrial and
commercial laundries. .
Types of Toxic Pollutants Discharged From Consent Decree Industrial Categories
Of the 67 CWA priority pollutants for which data were available in the DSS (as well as
copper and zinc, which were not included among the 165 DSS hazardous pollutants),8 Table
3-6 presents loadings under the raw loading, current, and after-PSES scenarios for the most
prevalent pollutants discharged to POTWs by Consent Decree industries. As shown, toxic
metals and volatile, organics tend to dominate total loadings under the raw discharge
scenario. However, the loadings of metals under the current and after-PSES scenarios drop
in ranking, probably because .most metals are regulated by categorical standards. On the
other hand, the loadings for most of the volatile organics remain high because categorical
standards for organics are not yet fully in place.
«* . . . ... -
As for the nonpriority toxic pollutants, the DSS estimated loadings for only the four
organic chemicals-related industries. The major nonpriority toxic pollutants identified include
methanol, xylene, formaldehyde, acetone, furfural, aniline, tetrahydrofuran, methyl isobutyl
ketone, formic acid, and cyclohexanone.
8. ' Although copper and zinc were not defined as hazardous pollutants .in the DSS, and
therefore not evaluated as part of the DSS, loading estimates were, provided in the DSS
report appendices. '
3-24
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Table 3-6. Top 20 Toxic Priority Pollutants With the Highest
Loadings for the Consent Decree Industrial Categories Within the Scope
.of the NRDC Consent Decree
Pollutant
Chromium & Compounds
Zinc .& Compounds
Nickel & Compounds
Cyanide
Phenol
Copper & Compounds
Methylene Chloride ' '
1,1.1 - Trichloroethane
Lead & Compounds
Toluene
Benzene
Ethyl Benzene
Trichloroethylene
Tetrachloroethylene .
Chloroform
Bis(2-ethylhexyl) Phthalate
2,4-Dimethyl Phenol
Naphthalene
Silver & Compounds
Arsenic & Compounds
Total
Raw Loading
(Ibs/yr)
66,426,800
40,669,200
31,946,200
31,732,800
28,604,400
27,392,200
12,498,200
11,162,800
11,004,400
9,035,400
5,104,000
4,925,800
4,864,200
4,393,400
4,283,400
. 2,888,600
2,547,600
2,523,400
1,982,200
1,766,600
305,751,600
Percent of
Total
22
13
10
10
9
9
4
4
4
3
2
2
2
1
1
1
1
1
1
,1
100
Pollutant
Phenol
Methylene Chloride
1,1,1-Trichloroethane
Toluene
Zinc & Compounds
Ethyl Benzene
Chromium & Compounds
Copper & Compounds
Chloroform
Benzene
Trichloroethylene
Lead & Compounds
Tetrachloroethylene
Nickel & Compounds
Cyanide
Bis (2-ethyhexyl) Phthalate .
Naphthalene
2,4-Dimethyl Phenol
Silver & Compounds
Acrolein
Total
Current (prior to PSES). Loading
(Ibs/yr)
23,625,800
12,056,000
8,635,000
7,959,600
5,570,400
4,793,800
4,527,600
4,149,200
4,180,000
4,089,800
3,795,000
3,438,600
3,313,200
3,194,400
3,159,200
2,655,400
2,017>400
1,735,800
1,647,800
1,645,600
106,189,600
Percent of
Total
22
11
8
7- -
5
5
4
• 4
4
4
4
3
3
3
3
3
2
2
2
2
100
3-25
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Table 3-6. Top 20 Toxic Priority Pollutants With the Highest
Loadings for the Consent Decree Industrial Categories Within the Scope
of the NRDC Consent Decree (continued)
Pollutant
Methylene Chloride
1,1,1-Trichloroethane
Toluene
Copper & Compounds
Trichloroethylene
Tetrachloroethylene
Ethyl Benzene
Chromium & Compounds
Chloroform
Antimony & Compounds
Phenol
Zinc & Compounds
Nickel & Compounds
Butyl Benzene Phthalate .
Cyanide
Benzene
Bis (2-ethyhexyl) Phthalate
Lead & Compounds
Silver & Compounds
2,4-Dimethyl Phenol
Total
After PSES Loading
(Ibs/yr)
11,877,800
8,632,800
4,426,400
4,015,000
3,784,000
3,102,000
2,615,800
2,512,400
2,512,400
2,169,200
2,043,800
1,900,800
1,738,000
1,474,000
1,388,200
1,240,800
1,170,400
1,141,800
792,000
514,800 .
59,052,400
Percent of
Total
20
15
7
.7
6-
•
5'
,
4
4
3
3
,
2
2
2
1.
.
100
Source: EPA (1986b).
3-26
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Other Industrial Categories •
The DSS relied on a variety of data sources to estimate the potential for discharge of
toxic pollutants by 17 non-Consent Decree industries. Appendix A-4 lists the toxic
pollutants identified in the DSS as being discharged to POTWs by these other industrial
categories. Table 3-7 estimates the number of facilities in each category and a summary of
the types of toxic pollutants identified for each category. Unfortunately, the data do not
differentiate facilities that discharge to POTWs (indirect dischargers) from those that
discharge to surface waters (direct discharges), and the table therefore includes both direct
and indirect dischargers.
At least 50 toxic pollutants were identified in the DSS as being discharged from the
following industrial categories: cosmetics, fragrances, flavors, and food additives (57 toxic
pollutants); food and food by-products (53 toxic pollutants); transportation services (56 toxic
pollutants); and waste treatment and disposal (50 toxic pollutants). The priority pollutant
toluene was identified in discharges from each of the 17 industrial categories. Other toxic
pollutants identified in at least 10 of the 17 industrial categories include:
1,1,1-^Trichloroethane*
1,2-Dichloroethane*
Acetone
Arsenic*
Benzene*
Carbon Tetrachloride*
* CWA Priority Pollutant
Chloroform* • Methanol
Chromium* • Methyl Ethyl Ketone
Cyanide* • Methylene Chloride*
Formaldehyde • Phenol*
Lead* . • Xylene.
Mercury*
3.2.2.3 Toxic Release Inventory System
As mentioned previously, TRIS was established under Section 313 of the 1986
Emergency Planning and Community Right-to-Know Act. Starting in 1987, the Act has
required certain industrial facilities to submit annually to the State and EPA a report
regarding releases to the environment of more than 300 listed toxic chemicals and chemical
categories. The specific information that pertains to this Report to Congress includes the
amounts and types of toxic pollutants discharged from industries to POTWs. There are
3-27
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3-28
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several limitations to using the THIS data base to describe toxic pollutant discharges to
POTWs:
• .The data set is limited to manufacturing facilities only. Therefore, many nonr
manufacturing industries (e.g., industrial laundries) tha.t may also release significant
quantities of pollutants to POTWs are not addressed.
• Only manufacturing facilities that handle large quantities of chemicals (i.e.,
.manufactured more than 50,000 pounds in 1988 or 25,000 pounds in 1989 and
subsequent years or use more than 10,000 pounds) are required to report. Therefore,
facilities handling small quantities of toxic pollutants, such as many electroplaters
and metal finishers, are not addressed.
• Facilities are only required to report estimates .of the quantities of toxic pollutants
released, and.for small releases need only report in ranges. Therefore, the actual
quantities discharged to POTWs may differ from the quantities reported.
• Only facilities with 10 or more full-tune employees are required to report. Again, this
may not include many small, industrial/commercial establishments (e.g., printing and
publishing, industrial.laundries, and electroplaters/metal finishers).
TRIS data reported for 1988 were extracted for use in this report. Release data were
organized by facility into the 47 industrial categories discussed in Subsection 3.2.2.1. The
basis for placing a facility into 1 of the 47 categories was the facility's primary Standard
Industrial Classification (SIC) code. Of the 5,748 facilities that reported releases to POTWs
in TRIS, 473 could not be categorized because of the absence of any SIC code for the facility.
According to the 1988 TRIS data, 5,748 facilities discharged over 680 million pounds of toxic
pollutants to over 1,700 POTWs in 1988 (see Table 3-8). Table 3-8 provides a summary of
data reported in TRIS for 38 industrial categories. TRIS did not contain data for all 47 of the
industrial categories that were discussed in Subsection 3.2.2.1. Appendix A-3 presents the
quantities of each toxic pollutant identified for each industrial category.
According to Table 3-8, TRIS reported the largest volumes of wastes being released to
POTWs from fertilizer manufacturers (143 million pounds), organic chemicals manufacturers
(92 million pounds), dye manufacture and formulation (68 million pounds), pulp and paper
mills (46 million pounds), food and food by-product processing (38 million pounds), and
pharmaceutical manufacturing (28 million pounds). Generally, the Consent Decree industrial
3-29
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Table 3-8. Summary of Data Reported in TRIS by Industrial Category
for 1988
Industrial Category
Adhcsives and Sealants
Battery Manufacturing
Coal, Oil, Petroleum Products and Refining
Cosmetics, Flavors, and Food Additives
Dye Manufacturing and Formulation
Electrical and Electronic Components
Electroplating/Metal Finishing
Equipment Manufacturing and Assembly
Explosives Manufacturing
Fertilizer Manufacturing .
Food and Food By-Product Processing
Gum, Wood Chemicals, Varnishes and Lacquer
Ink Manufacturing and Formulation
Inorganic Chemicals Manufacturing
Iron and Steel Manufacturing and Forming
Laboratories and Hospitals
Leather Tanning and Finishing.
Miscellaneous Chemical Formulation
Motor Vehicle Services
Nonferrous Metals Forming
Nonferrous Metals. Manufacturing
Organic Chemicals Manufacturing
Paint Manufacturing
Pesticide Manufacturing and Formulation***
Pharmaceutical Manufacturing
Plastics, Resins, and Synthetic Fibers
Plastics Molding and Forming
Printing and Publishing
Pulp and Paper
Rubber Manufacturing
Service Related Industry (Non-Motor Vehicle)
Soap and Detergents Manufacturing
Number of
Facilities
Reporting
73
83
69
34
72
339
859
1,145
. 4
101
506
3
15
21
146
2
40
132
1
127
86
173
118
21
108
165
64
62
52
92
2
. 226
Number of
POTWs
Receiving*
74
76
60 .'.
30
51
296
684
969
4
98
473
3
15
20
151
2
37
122
1
125
83
149
114
22
95
153
62
57
52
88
2
210
Number of
Pounds
Discharged
to POTWs**
196,138
884,195
11,097,249
1,184,756
68,278,270
14,294,031
20,133,640
27,063,119
75,654
143,490,850
38,254,618
333,351
353,961
4,791,581
17,455,097
114,532
12,505,998
10,172,642
21,000
3,212,220
1,587,918
92,815,513
4,221,248
663,684
28,419,701
9,132,905
971,842
508,144
46,675,179
630,015
7,968
4,231,307
3-30
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Table 3-8. Summary of Data Reported in TRIS by Industrial Category
for 1988 (continued)
Industrial Category
Stone, Clay, Glass, and Concrete
Textile Mills
Timber Products Processing
Transportation Services ,
Wholesale and Retail Trade
Wood Furniture Manufacturing and Refinishing
Miscellaneous****
Totals
Number of
Facilities
Reporting
118
125
51
1
6
33 '
473
5,748
Number of
POTWs
Receiving*
120
107
49
1
7
31
444
NA
Number of
Pounds
Discharged
to POTWs**
2,754,495
10,783,040
72,748
410
27,220
227,473
103,143,000
680,786,712
NA'- Not applicable.
* Due to the fact that a POTW may receive wastes from facilities in more than one industrial category, a
total number for this column would result in double counting. The actual number of POTWs identified
in TRIS'is 1,717. Also note that for certain industrial categories (e.g., adhesives and sealants), the
number of POTWs receiving wastes is greater than the number of facilities reporting. This occurs
because several facilities reported discharges to more than one POTW.
** AH discharges are reported in pounds per year.
*** This includes both Pesticides Manufacturing and Pesticide Formulating Categories.
**** This category includes all facilities reported hi TRIS that could not be categorized because of the absence
of an SIC code. ....
Source: TRIS (1988).
3-31'
-------
categories report greater quantities of pollutants being released to POTWs than do the non-
Consent Decree industries.9
More than 200 toxic pollutants were reported to be discharged to POTWs in quantities
ranging from 187 billion pounds per year (ammonium -sulfate) to 2 pounds per year
(tetrachlorvinphos). In an effort to determine which of the toxic pollutants being reported in
TRIS could be considered, significant from a national perspective, the toxic pollutants released
by 10 or more facilities were ranked according to the total amount discharged (see Table
3-9).10 • ; .
Because pollutants differ in the potential severity of their effects (for example, a pound
of zinc discharged to a POTW will have a lesser effect than a pound of benzene), EPA took a
further step to assess the relative importance of the loadings or each pollutant listed in Table
3-9. EPA normalized or standardized the total numbers of pounds of each priority pollutant
reported in TRIS in terms of its toxicity to aquatic life and human Health. To do this, EPA
computed toxic weighting factors by multiplying the inverse of applicable EPA water quality
criteria (i.e., chronic freshwater aquatic and human health criteria) for each pollutant by a
" , '. " •;,,,",.; . "l!'i ;«,,;:• ; J.i!"!M!.,i.'V •', •) . , .VI .J '«, , L ri •' , . • • i..1.. '
standard.11 Copper was selected as the standard pollutant for developing weighting factors
since it is a toxic metal pollutant and is commonly detected and removed from industrial
effluents.12 The resultant toxic weights were then multiplied by the number of pounds
reported in TRIS, resulting in the number of toxic pound equivalents for the pollutant
9., The larger quantities being reported by Consent Decree industrial categories are
expected because the Consent Decree industrial categories cover most of the
manufacturing facilities required to report. /
10. It should be noted that even a small quantity of a toxic pollutant may be significant for the
particular POTW that receives the pollutant. However, for purposes of this report,
nationally significant toxic pollutants include those pollutants discharged in large
quantities and by many facilities. Toxic pollutants were not considered nationally
significant if they were discharged by fewer than 10 facilities. There were 113 toxic
pollutants for which fewer than 10 facilities reported discharges to POTWs.
11. Since the development of toxic weights is dependent on the use of EPA water quality
criteria, this analysis is limited to only those priority pollutants reported in TRIS for
which chemical-specific water quality criteria are available.
12. This same procedure is used by the EPA Office of Water Regulations and Standards as
part of its cost-effectiveness analyses of proposed regulatory options for effluent
guidelines and categorical pretreatment standards.
3-32
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Table 3-9. Summary of Toxic Pollutants Reported as Being Released by
10 or More Facilities to POTWs in TRIS for 1988
Pollutant
Ammonium Sulfate (solution)
Methanol .
Barium and Compounds
Sulfuric Acid
Hydrochloric Acid
Nitric Acid ; ' . .
Ammonia
Ethylene Glycol
Acetone
Phosphoric Acid
Glycol Ethers
Ammonium Nitrate (solution)
Phenol*
Aluminum Oxide
Formaldehyde
N-Butyl Alcohol
Xylene (mixed isomers)
Toluene*
Chlorine
Dichloromethane
Zinc (fume or dust)*
Vinyl Acetate,
Chromium and Compounds
Aniline
Manganese and Compounds
Diethanolamine
Methyl Isobutyl Ketone
1 ,2rDichloroethane*
Biphenyl
Chloroform*
.Cyanide Compounds*
Benzene*
Pounds to
POTWs
187,006,695
111,590,690
100,943,818
61,481,639
36413,709
23,552,392
22,319,809
16,322,723
14,170,522
13,875,279
8,532,603
7^595,942
5,723,727
5,601,977,
4,632,348
4,511,588
4,158,305
3,545,408
3,125,880
2,585,199
2,426,892
2,319,733
2,102,584
2,098,710
2,010,573
1,899,977
1,508,780
1,477,242
1,428,510
1,226,573
. , 1,148,625
1,103,01-5
Total
Facilities
Reporting
Release
155
490
183
951
561
415
.518
472
330
649
518
23
167
224
239
133
370
464
216
257
419
45
658
24
.278
116
95
21
57
36
216
80
Minimum
Discharge
(Ibs/yr)
11
1
1
1
1
1
2
1
1
1
1
250
1
1
1.
. ' 5.
1
1
1
1
1
1
; 1
3_
1.
2
1
1
2
''.'.' 1
1
'l
Maximum
Discharge
(Ibs/yr)
52,345,936
7,922,060
100;000,000
9,440,000
14,000,000
15,000,000
1,411,600
2,828,400
2,400,000
455,130
1,410,000
1,713,000
1,412,000
2,500,000
1,291,582
1,300,000
720,000
560,931.
332,000
1,100,000 :
685,000
2,146,712
520,000
563,292
1,646,000
630,000
400,000
1,300,000
165,971
358,530
845,000
440,000
3-33'
-------
Table 3-9. Summary of Toxic Pollutants Reported as Being Released by
10 or More Facilities to POTWs in TRIS for 1988 (continued)
Pollutant
Acrylonitrile*
Methyl Ethyl Ketone
Nickel and Compounds
Naphthalene*
Hydrogen Fluoride
2-Methoxyethanol
Acetonitrile
Tetrachloroethylene*
Chlorobehzene*
Maleic Anhydride
Hydroquinone
Dimethyl Phthalate
Ethylbenzene*
1 ,2,4-Trimethylbenzene
Styrene
Copper Compounds*
Propylene Oxide
Cresoi (mixed isomers)*
Ethylene Oxide
1,1,1-Trichlorbethane*
Pyriduie
1,2,4-Trichlorobenzene*
Catechol
Lead and Compounds*
Acetaldehyde
Cumene
2-Ethoxyethanol
Methyl Methacrylate
Di(2-Ethylhexyl) Phthalate
Carbon Disulfide
Cyclohexane
Antimony and Compounds*
Pounds to
POTWs
955,741
932,817
885,281
772,468
711,889
662,102
594,769
586,638
578,774
556,373
510,560
508,571
507,325
496,817
'471,291
707,495
407,276
357,992
343,298
295,719
275,083
261,676
245,399
209,468
206,050
203,279
196,286
191,578
168,491
159,369
140,917
107,567
Total
Facilities
Reporting
Release
29
172
587
81
75
17
21
87
!5
18
24
10
115
27
85
330
26
21
44
408
11
28
10
454
12
16
25
53
31
15
30
91
Minimum
Discharge
(Ibs/yr)
2
1
1
1
1
1
3
1
1
2
3
250
1
2
1
1
18
1
2
1
44
4
1,000
1
71
1
1
7
1
57
1
'1
Maximum
Discharge
(Ibs/yr)
488,139
296,000
417,000
610,000
187,200
483,000
180,000
103,574
200,000
550,000
366,000
490,000
150,000
390,000
- 180,204
96,243
197,138
250,000
78,204
27,170
129,648
59,922
71,000
58,178
82,830
150,000
72,100
35,000
140,000
70,000
12,000
15,701
3-34"
-------
Table 3-9. Summary of Toxic Pollutants Reported as Being Released by
10 or More Facilities to POTWs in TRIS for 1988 (continued)
Pollutant
Freon 113
Trichloroethylene*
Epichlorohydrin
1 ,2-Dichlorobenzene*
Chloromethane*
Phthalic Anhydride
Dibenzofuran
Butyl Benzyl Phthalate*
O-Xylene
Bis(2-Ethylhexyl) Adipate
Benzyl Chloride
Sec-Butyl Alcohol
Diethyl Phthalate*
Cobalt and Compounds .
Dibutyl Phthalate*
Butyl Acrylate
4,4'-Isopropylidenediphenol
Ethyl Acrylate
Acrylic Acid
Aluminum (Fume or Dust)
Anthracene*
Cadmium and Compounds*
Decabromodiphenyl Oxide
Methyl Acrylate
Acrylamide
Methyl Tert Butyl Ether
Silver and Compounds*
Pentachlorophenol*
Arsenic Compounds*
Pounds to
POTWs
104,913
79,258
73,385
64,118
53,973
53,441
47,726
44,235
44,023
42,569
41,553
41,108
37,350
36,784
36,770
34,615
31,135
27,657
.23,187
18,324
20,432
. 20,635
19,090
14,886
13,493
7,713
8,906
4,728
3,126
Total
Facilities
Reporting
Release
76
114
20
14
18
23
26
29
11
11
17
12
12
74
36
52
11
33
34
45
34
82
10
16
23
10
44
17
16
Minimum
Discharge
(Ibs/yr)
1
1
4
13
1
4
..-. 1 '
'2
1
2
19
250
1
8
1
.1
35
1
1
3
1
1
5
1
4
38
.1
2
1
Maximum
Discharge
(Ibs/yr)
35,061
39,797
65,000
28,404
37,975
19,000
44,273
13,000
33,689
17,000
28,700
13,300
16,812
7,573
6,886
10,000
18,000
6,500
5,800
3,900'
14,736
1,800
8,590
11,000
6,300
4,035
770
2,100
750
*Clean Water Act Priority Pollutant
Source: TRIS (1988)
3-35
-------
The results of the toxic weighting analysis for the priority pollutants reported in TRIS
are shown in Table 3-10. As shown in Table 3-10, acrylonitrile has the highest toxic pound
equivalents of all the priority pollutants reported in TRIS. Other priority pollutants with high
toxic pound equivalents are chloroform, benzene, 1, 2-dichloroethane, and arsenic.
Although a pollutant may be discharged in large quantities, it may not be significant
nationally if only several facilities discharge the pollutant Further analysis of the TRIS data
reveals that the total amounts of several pollutants discharged to POTWs were skewed by
the discharge from a single facility. Specifically, there are 79 toxic pollutants for which 75
percent or more of the total amount reported as discharged is due to the discharge from one
facility.13 In an attempt to account for skewed data, the amount attributed to facilities that
discharged 75 percent or more of the total for a pollutant was subtracted from the total. The
associated total number of facilities discharging each pollutant was also adjusted to account
for the loss of one facility. The resulting adjusted total pounds discharged and number of
facilities discharging were then used to rank the toxic pollutants to account for both the
amount of pollutant discharged and the number of facilities reporting its discharge to POTWs.
Specifically, each pollutant was ranked based on its relative proportion to the maximum
adjusted total pounds discharged for a pollutant and its relative proportion to the maximum
adjusted tQtal number of facilities for a pollutant. These relative proportions were then added
together to arrive at an overall ranking for each pollutant in TRIS. Appendix A-5 displays the
results of these rankings.
.-. ••;' - ' . , i • ' • f • ;,:• , " ,•!':,.••.'•'•.. ••,;. •;
'' : ,' . . ' ' I! I': " ;'>,: ': M1 ' •• ' '..': -1'' ' "''" •''' " "'•" ."' ': :
"•Using the ranking and adjustment discussed above, Table 3-11 presents the top 40
pollutants'being discharged to POTWs as reported in TRIS. As noted, sulfuric acid was
reported to be the pollutant discharged in the highest amount and.by the most, facilities.
The most significant nonpriority toxic organic pollutants.reported in Table 3-11 include
methanol, ethylene glycol, acetone, formaldehyde, methyl ethyl ketone, butanol,
diethanolamine, methyl isobutyl ketone, and styrene. .Two nonpriority metals, manganese
and barium, were also ranked in the top 40 pollutants reported, the remainder of the top 40
toxic pollutants reported in TRIS consisted primarily of nonconventional pollutants (e.g.,
13. For purposes of this analysis, if a single facility reported 75 percent or more of the total
amount for a given pollutant, that pollutant loading was not considered nationally
significant. •.
3-36
-------
Table 3-10. Summary of Toxic Pound Equivalents for the Priority
Pollutants Reported As Being Released to POTWs in TRIS for 1988*
CWA Priority Pollutant
1,1,1-Trichloroethane
1,2,4-Trichlorobenzene
1,2-Dichlorobenzene
1 ,2-Dichloroethane
Acrylonitrile
Antimony and Compounds
Arsenic and Compounds
Benzene
Cadmium and Compounds
Chlorobenzene
Chloroform
Chromium and Compounds •
Copper and Compounds
Cyanide Compounds
Dibutyl Phthalate
Diethyl Phthalate
Ethylbenzene
Lead and Compounds
Naphthalene
Nickel and Compounds
Pentachlorophenol
Phenol
Silver and Compounds
Tetrachloroethylene
Toluene
Trichloroethylene
Zinc (Fume or Dust)
Pounds
Released to
POTWs as
Reported in
TRIS**
295,719
261,676
64,118
1,477,242
955,741
107,567
5,051
1,103,015
20,365
578,774
1,226,573
2,102,584
707,495
1,148,625
36,770
37,350
507,325
209,468
772,468
885,281
4,728
5,723,727
8,906
.586,638
3,545,408
79,258
2,426,902
Aquatic
Chronic
Water
Quality
Criteria***
(Hg/»
--
50
763
20,000
2,600
1,600
—
1.1
. 50
1,240
11
12
5.2
-
.'•--•
--
3.2
620
160
13
2,560
0.12
840
. • --
21,900
110
Human Health
Water Quality
Criteria***
(Hg/0
18,400
488
400
0.94
0.058
146
0.0022
0.66
. 10
488
0.19
50
-- .
200
3,500
350,000
1,400
50
.. .-
13.4
1,010
3,500
50
0.8
14,300
2.7
-- '
Toxic
Weighing
Factor
0.00065
0.26459
0.04573
12.76656
206.90117
0.08969 .
5,454.54545
18.18182
12.10909
0.26459
63.16757
1.33091
1.00000
2.36769
0.00343 .
0.00003
0.00857
3.99000
0.01935
0.97052
0.93496
0.00812
100.24000
15.01429
. 0.00084
4.44499
0.10909
Toxic Pound
Equivalent
192
69,237
2,932
18,859,299
197,743,931
9,648
27,550,909
20,054,820
246,602
153,138
77,479,636
2,798,350
707,495
2,719,588
126
1
4,348
835,777
14,947
859,183
4,420
46,477
892,737
8,807,953
2,978
352,301
264/751
N/A - Not Applicable; water quality criteria not available for this specific pollutant.
* This analysis is limited to priority pollutants reported in TRIS for which chemical-specific water quality
criteria are available. .
** Source: EPA Toxics Release Inventory System (1988)
*** Source: EPA Water Quality Critria (EPA 1986)
3-37 -
-------
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sulfuric acid, hydrochloric acid, nitric acid) that were reported to be released to POTWs in
significant quantities and that could pose more of a collection system problem .(e.g.,
corrosion) than, a toxic effect in a POTW treatment.plant. Still others (e.g., ammonium
sulfate, ammonium nitrate) are commonly used as water treatment chemicals.
Generally, loadings for many toxic pollutants reported in TRIS as being discharged to
POTWs were higher than the loadings estimated in the DSS. Table 3-12 compares, by
industrial category, TRIS data to DSS data for the Consent Decree industrial categories14
and only for the 165 pollutants examined by the DSS (as well as copper and zinc). Appendix
A-3 presents a detailed comparison by pollutant and industrial category. As shown in the
table, reported TRIS estimates for eight of the industrial categories under the raw loadings
scenarios are higher than those provided in the DSS. However, for almost all industrial
categories, the TRIS estimates exceed .the after-PSES DSS estimates. Although this would
be expected since most of the DSS estimates were based primarily on priority pollutants,
TRIS estimates also exceed those DSS estimates for the organic chemicals manufacturing
industrial categories, where estimates of nonpriority pollutants were available.
* j '
The discrepancy between the TRIS and DSS loadings is most likely due to the
differences in the methods used to .derive the loadings. The TRIS loadings represent the
number of pounds of pollutants discharged to POTWs as reported to EPA for releases to
POTWs in 1988. The DSS loadings represent the number of pounds of pollutants discharged
to POTWs as estimated by EPA based on representative industrial category pre-1986 data
scaled up to derive national estimates. It should also be noted that most of the TRIS
estimates were based on a smaller number of facilities than the number of facilities used to
estimate the pollutant loadings in DSS. This is partially because only the larger
manufacturing facilities were required to report under TRIS. Therefore, precise comparison of
TRIS and DSS is impossible. Examination of the average total pounds per year discharged to
POTWs by a facility also shows that TRIS estimates almost always exceed the after-PSES
estimates given by DSS; TRIS average per facility estimates exceed DSS raw loadings for
almost 50 percent of the industrial categories.
14. DSS did not provide quantitative estimates for non-Consent Decree industrial
categories. . '
3-39
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3-41
-------
Comparison across the Consent Decree industrial categories shows that according to
TRIS, the larger loadings of toxic pollutants are discharged from the organic chemicals (i.e.,
organic chemicals manufacturing; dye manufacture and formulation; and plastics, resins, and
synthetic fibers), pharmaceutical manufacturing, and pulp and paper industrial categories.
This contrasts slightly with the DSS estimates, which identified several metals-related
industrial categories as significant contributors of toxic pollutants (e.g., electroplating/metal
finishing, equipment manufacture). This difference appeared/particularly with the
electroplating/metal finishing and equipment manufacture industrial categories, where a
significant portion of the total number of facilities is expected to be relatively small in size
and, therefore, exempt from TRIS reporting requirements.
' Many of the same toxic pollutants identified in the DSS were also reported in the TRIS
data base as being discharged to POTWs by industries. However! several other pollutants
were also identified by TRIS for many of the industrial categories. For example, the organic
chemicals manufacturing industry had 96 toxic pollutants identified by TRIS that were not
identified in the DSS., The most common pollutants in TRIS for which estimates were not
provided in the DSS were nonpriority toxic pollutants, including acetone, methyl ethyl ketone,
and methanol.
3.2.2.4 304(m) Studies
Section 304(m) of the CWA directs EPA to publish a plan every 2 years for the review
and revision of effluent limitations guidelines (including categorical standards) and the
promulgation of new guidelines covering industrial categories that discharge toxic and
nonconventional pollutants. Specifically, the biennial plans must establish a schedule for
annual review and revision of previously promulgated effluent guidelines, identify categories
for which guidelines have not been published previously, and establish a schedule for
promulgation of guidelines for the new categories. EPA's Office of Water Regulations and
Standards ITD prepared-a. series of preliminary data summaries in its first biennial 304(m)
plan. The summaries contain engineering, economic, and environmental data used in
determining the categories that merited priority in the preparation of new and revised
regulations. Of the industrial categories for which preliminary data summaries were
prepared, 10 included indirect dischargers to POTWs.
This subsection summarizes the findings of the 10 preliminary data summaries that
addressed indirect dischargers. The findings are of particular interest, because they highlight
the types and quantities of toxic pollutants that are potentially discharged by facilities that
,",! ' n .. ^. . " '' « , *" "
3-42 ' '" " • ""
-------
have not generally been subject to regulation at the national level. In the absence of local
control, particularly for those pollutants not typically monitored (e.g., toxic organics), these
industries can contribute large quantities of toxic pollutants to POTWs.
The following summaries, extracted from EPA's studies, generally characterize the
wastewaters generated by each 304(m) category. This review focuses on all pollutants,
except conventional pollutants, Identified by EPA during the studies. Appendix A-6
summarizes the analytical results for each of the industrial categories. Table 3-13
summarizes the numbers and.types of pollutants detected during analyses of wastewaters
from these industrial categories.
• Machinery Manufacturing and Rebuilding (MM&RY—One hundred and thirty-five
toxic pollutants (73 of which were priority pollutants) were found above detection
levels in MM&R wastewaters (EPA, 1989f). Based on these data, EPA estimates
that the MM&R industry generates raw (i.e., untreated) wastewater containing 150
million pounds of toxic metals per year and 36 million pounds of toxic organics per
year. The presence of toxic metals would be expected because most machinery parts
are constructed of metals aind the processing of these metals results in their presence
in wastewaters. The toxic organics found in MM&R wastewaters can be associated
with their use as solvents, cleaners, processing aids, and strippers in machinery
manufacturing processes.
• Drum Reconditioning—Drums are used to hold a vast array of substances, including
oil and petroleum, industrial chemicals, paints and inks, solvents, resins, adhesives,
pesticides, and food products. As a result, the composition of drum reconditioning
wastewaters varies (EPA, 1989b). The toxic organics detected in raw wastewaters
at certain plants are 1,1,1-trichloroethane, 2-butanone, 2-chloronapthalene, benzoic
acid, benzyl alcohol, biphenyl, ethylbenzene, hexanoic acid, methylene chloride,
naphthalene, n-hexadecane, nitrobenzene, p-cymene, styrene, toluene, and
trichloroethylene. Acetone had the highest average concentration (858 mg/1) of those
toxic organic pollutants detected at greater than 10 mg/1. The predominant
metals/inorganics detected in the raw wastewaters were aluminum, iron, lead,
magnesium, sodium, calcium, and zinc.
• Industrial Laundries—Thirty-nine toxic pollutants (38 of which were priority
pollutants) were identified in raw wastewater from industrial laundries (EPA,
1989e). Although many volatile organic compounds were detected in at least one of
the nine samples analyzed, most of the toxic metals (i.e., antimony, cadmium,
chromium, copper, lead, nickel, and zinc) were detected in all raw wastewater
3-43
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samples analyzed. Using these sampling results and assuming a population of 1,000
industrial laundries, EPA projected the following estimates of the annual raw waste
loadings of toxic pollutants from the industrial laundry industry:
— Nonpriority Pollutants (Ibs/year)
Volatile Organics 24,000,000
Semivolatile Organics 3,000,000
Pesticides and Herbicides 200,000
Metals/Inorganics 1,500,000
— Priority Pollutants (Ibs/year)
Volatile Organics 1,500,000
Semivolatile Organics 2,000,000
Pesticides and Herbicides 30,000 .
Metals/Inorganics 1,600,000 ,
Cyanide 300,000.
Paint Formulating—Twenty organic compounds were detected in the raw wastewater
samples, with acetone found at the highest concentration (greater than 1,000 mg/1)
(EPA, 1989g). Twenty-two metals were also detected in the raw wastewater
samples, with aluminum, calcium, iron, magnesium, sodium, and zinc found at the
highest concentrations, .
Pharmaceutical Manufacturing—Sixty-nine toxic pollutants were detected in
pharmaceutical manufacturing wastewaters (EPA, 1989h). The most prevalent toxic
pollutants found by EPA in these wastewaters included volatile organics and metals.
Using the data collected for the study, EPA estimated the following quantities of toxic
pollutants in raw wastewaters from indirect discharging, pharmaceutical
manufacturing facilities:
- Nonpriority Pollutants (Ibs/year)
Volatile Organics 9,900,000
Semivolatile Organics 112,000
Pesticides and Herbicides 118,000
- Priority Pollutants (Ibs/year)
Volatile Organics 2,418,000
Semivolatile Organics 406,000
Pesticides and Herbicides 20
Metal 53,000 .
Cyanide 4,600.
3-45
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Hazardous Waste Treatment—Eighty-two toxic pollutants were detected in raw
wastewaters generated by hazardous waste treaters (EPA, 1989c). The most
prevalent types of toxic pollutants found in raw wastewater from hazardous waste
treaters included volatile organics (e.g., acetone, benzene, toluene, methylene
chloride, and methyl ethyl ketone) and metals. Using the data collected, EPA
estimated that 36 million pounds of toxic organics and 305 million pounds of metals
are present each year in the raw wastewater of hazardous waste treaters.
Transportation Equipment Cleaning—Eighty-eight toxic pollutants were detected in
raw wastewfters generated by facilities in this industrial category (EPA, 1989J).
The predominant toxic pollutants detected included acrylonitrile, acrolein, benzene,
arsenic, and cyanide. The total discharge of priority pollutants from this industry is
estimated at approximately 22 million pounds per year.
Used Oil Reclamation and Re-Refining—Fifty-seven toxic pollutants were detected
in wastewaters from used oil facilities (EPA, 1989k). The most prevalent pollutants
found in the raw wastewaters from these facilities included lead, tetrachloroethylene,
toluene, 1,1,1-trichloroethane, trichloroethylene, and napthalene.
' ... . • , • ' •••,., ; !' ., . ''-',;.'/ii.'i !• >:•'., "'sitSa'S'liV',.1'",'-,;!''-! .'•. •• v;,-il'."!:v! '":•':; i.r, ', •' •• ,'i*.J "•»'", v v:
Hospitals—A total of 27 toxic pollutants were detected in raw wastewaters from
hospitals (EPA, 1989d).- EPA projected the following annual loadings of toxic
pollutants in raw wastewaters:
: '. Y • ' '.,' • ' ,•••. ./]'•;•; Y h; ':,,'•.. :. :Y:V'ir"'i ; •(,'•":',•'''^'^^t'^,
- Nonpriority Pollutants (Ibs/year)
Volatile Organics 545,675
• ' Metals • _ ..'.314,995 ' ' :": X"
- Priority Pollutants (Ibs/year)
Volatile .Organics . 37,960
Semivolatile Organics 56,210
Metals " 255,135.
The primary sources of wastewater in hospitals are sanitary .wastewater and
discharges from surgical rooms, laboratories, laundries, x-ray departments,
cafeterias, and glassware washing. The types of waste generated by hospitals
generally include (1) chemical waste, such as spent solvents, acids, caustics, and
metals, (2) radioactive waste, including radioisotopes with low radioactive levels and
generally short half-lives, and (3) infectious waste, consisting primarily of
contaminated synthetic materials, such as plastic tubing and paper products.
Solvent Recycling—Sixty-six toxic pollutants were detected in the raw wastewaters
from solvent recyclers (EPA, 1989i). The predominant toxics found in these raw
wastewaters were extractable/volatile organics (e.g., acetone, methylene chloride,
1,1,1-trichloroethane); some of these organics were detected at concentrations
exceeding 100 mg/1.
3-46-
-------
As shown above, a variety of toxic pollutants have been found in the raw wastewaters
generated by facilities in a number of industrial categories. Initial estimates by EPA show
that significant quantities of toxic pollutants could be discharged to POTWs if the waste is
untreated or improperly treated. The most significant type of toxic pollutant generated by the
10 industrial, categories studied by EPA are the nonpriority volatile organic pollutants. For
those industries where estimates were provided, the loadings of nonpriority toxic organics
ranged from 545,000 pounds per year for hospitals, to 24 million pounds per year for industrial
laundries. .
3.2.2.5 State Monitoring Data
Examination of-actual POTW and industrial user monitoring data can provide additional
insights into the types and quantities of toxic pollutants discharged to POTWs that may not
be gained using national studies and data bases. Most POTW and IU monitoring data are
maintained at the POTW level; collection, organization, and summary of all industrial user
monitoring data collected at the POTW level were not possible for this report The State of
North Carolina maintains perhaps the most comprehensive data base of industrial user
monitoring data at the approval authority (State) level. This subsection presents industrial
user monitoring data collected and compiled by the North Carolina Department of Natural
Resources and Community Development. .
Summary of Industrial Types -
Monitoring data exist for one or more pollutant parameters for 929 industrial users in
the North Carolina Industrial Users Data Base (described in Chapter 2). These industrial
users were placed into the 46 industrial categories.described in Subsection 3.2.2.1 in
accordance with the primary SIC code(s) assigned to each industrial category.15 Table 3-14
lists the number of North Carolina industrial users in each of the 46 industrial categories. It
should be noted that 213 industrial users covered in the North Carolina data base could not
be placed into the 46 industrial categories, because SIC codes were not reported for these
facilities. Table 3-14 categorizes these 213 users as "Miscellaneous."
In North Carolina, industrial users represent at least 36 of the 46 industrial categories
examined in this study. The four industrial categories having the most industrial users are
15. The North Carolina Industrial Users Data Base contained two categories—pesticide
manufacturing and pesticide formulating—which were combined in this analysis, lowering
the number of categories from 47 to 46.
3-47
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Table 3-14. Summary of North Carolina Industrial Dischargers That
Report Effluent Monitoring Results to the State
Industrial Category
Total Number of
Facilities Reporting
Adhesives and Sealants
iattery Manufacturing
Coal, Oil, and Petroleum Products and Refining
Construction Industry (contract and special trade)
Cosmetics, Fragrances, Flavors, and Food Additives ,
Dye Manufacture and Formulation
Electric Generating Power Plants and Electric Distribution Services
Electrical and Electronic Components
Electroplating/Metal Finishing
Equipment Manufacture and Assembly
Explosives Manufacture
Fertilizer Manufacture
F.ood and Food By-Products Processing •
Gum and Wood Chemicals, Varnishes, Lacquers, and Related Oils
Hazardous Waste Site Cleanup
Industrial and Commercial Laundries
fnk Manufacture and Formulation
Enorganic Chemicals Manufacturing
Iron arid Steel Manufacturing and Forming
Laboratories and Hospitals
Leather Tanning and Finishing
Miscellaneous Chemical Formulation
Motor Vehicle Services , .
Nonferrous Metals Forming
Nonferrous Metals Manufacturing
Organic Chemicals Manufacturing
Paint Manufacture and Formulation
Pesticide Manufacturing and Formulating*
Pharmaceutical Manufacturing
Photographic Chemicals and Film Manufacturing
Plastics Molding and Forming
Plastics, Resins, and Synthetic Fibers Manufacturing
Porcelain Enameling
Printing and Publishing
Pulp and Paper Mills
Rubber Manufacture and Processing
Service Related Industries (other than vehicle services)
Soap and Detergents, Cleaning Preparations, and Waxes
Manufacture and Formulation
Stone, Clay, Glass, Concrete, and Other Mineral Products
Textile Mills
Timber Products Processing •
1
5
4
1
4
2
ND
12
86
117
ND
. 1
89
ND
ND
22
1
ND
4
27
ND
1
6
8
1
5
.5
I
8
ND
6
5
ND
7
1
10
6
9
15
206
4
3-48
-------
Table 3-14. Summary of North Carolina Industrial Dischargers That
Report Effluent Monitoring Results to the State (continued)
Industrial Category Total Number of
Facilities Reporting
Transportation Services 14
Waste Reclamation Services ND
Waste Treatment and Disposal Services ND
Wholesale and Retail Trade -2
Wood Furniture Manufacture and Refinishing 20
Miscellaneous** 213
Total 929
* This includes two industrial categories: Pesticides Manufacturing and Pesticides Formulating.
** This category includes facilities that could not be categorized because of the absence of SIC codes for
these facilities in the data base. . .
ND = No data. .
Source: North Carolina Department of Natural Resources and Community Development (1990).
3-49
-------
textile mills (206 industrial users), equipment manufacture and assembly (117), food and food
by-products processing (89), and electroplating/metal finishing (86).
' ' ' ' ,' I-1,, ' ' ';',' ".,,.: ' , " l!1' 'I " ! •', •
Summary of Monitoring Data . •
For this study, all monitoring data associated with the 929 North Carolina industrial
users were extracted and summarized by industrial category. Presented in Appendix A-7,
this summary identifies several industries mat are not regulated at the national level through
categorical standards and that discharge a number of toxic pollutants. For example:
• Total metals concentrations averaged 15 mg/1 for discharges from a fertilizer .
manufacturer; total copper levels for this discharge averaged 3.49 mg/1.
• Significant concentrations of total chromium (4.4 mg/l), copper (17.0 mg/1), lead (17.7
mg/1), and zinc (2.3 mg/1) were reported for an ink manufacturer.
• An average of 33.71 mg/1 of .phenol was reported for the 27 facilities in the
laboratories and hospitals category.
• Mercury concentrations ranging from 0.0007 mg/1 to 18.0 mg/1 were reported for wood
furniture manufacturing and refinishing category. Copper concentrations for this
category ranged from 0.01 mg/1 to 72.64 mg/1.
" • Industrial users in the transportation services category were reported to discharge
significant concentrations (6.42 mg/1) of total metals.
: '•' • • ' ' "' '.,"'• •',. Y :••}. Y •'^fbY ;; Y,; :•.••,•.'.;.•.. - ..•.'. ;^:
The toxic pollutants for which monitoring is required of industrial users in North Carolina •.
are primarily metals/inorganics (e.g., silver, aluminum,,arsenic, cadmium, cyanide (total),
cyanide (amenable), copper, chromium, iron, fluoride). Few facilities are required to monitor •.
for toxic organic pollutants. Specifically, but of the 716 facilities for which an industrial
category could be identified, only 95 are required to monitor for phenols; 28 are required to
monitor for the aggregate parameter total toxic organics (TTO). Further, all of the TTO
monitoring is associated with those metals industries subject to TTO limitations contained in
categorical standards (e.g., electroplating). Therefore, many of the industries where toxic
organics would be expected to be present (e.g., industrial laundries, pharmaceutical
manufacturers, and organic chemical manufacturers) are not required to monitor for these
pollutants.
3.3 DOMESTIC SOURCES OF TOXIC POLLUTANTS
Traditionally, domestic discharges to POTWs have been considered simply a source of
suspended solids and degradable organic materials, as compared to industrial arid commercial
sources, which are often associated with toxic pollutants. For many POTWs, however,
3-50
-------
domestic flows make up a large part of the total flow received (see Table 3-2). This, coupled
with the fact that toxic pollutants have been found in domestic wastewater, indicates that
discharges of domestic wastewater can be a significant source of toxic pollutant loadings to
POTWs. This section examines the types and extent of toxic pollutant discharges associated
with domestic sources.
3.3.1 Characterization of Domestic Wastewater
To characterize wastewater from domestic sources, EPA used monitoring data
presented in the Supplemental Manual (EPA, 1991). The manual presents data reported by
15 municipalities located in seven EPA regions, all of which monitored sewer trunk lines
receiving wastewaters exclusively from residences and small commercial sources.
Table 3-15 identifies overall average inorganic pollutant levels for domestic
f i' • ' • •
contributions, while Table 3-16 stiows overall average organic pollutant levels. Single point
values for the maximum and minimum for each pollutant were provided to define the range of
values considered. Note that these tables reflect only pollutants monitored and reported by
the 15 municipalities; the fact that other pollutants (such as chlorine) are not reported does
not mean they are not present in domestic wastewaters.
Table 3-15 indicates the high levels of ammonia and phosphate normally associated,
-with sanitary wastewater, as well as an elevated level of fluoride, which is commonly
associated with the fluoridation of drinking water. A variety of metals occur, with relatively
high levels of copper, iron, lead, and zinc, which are probably associated with corrosion of the.
water and wastewater conveyance system. Furthermore, zinc may also be introduced into
the system by the addition.of zinc orthophosphate, which is often added at the treatment
plant to control corrosion in the distribution system. It is not possible to determine whether
the other pollutants originate in source water or the extent to which they reflect domestic
sources.
Table 3-16 shows measurable levels of three pesticides (BHC, 4,4-DDD, and
endosulfan); a plasticizer (bis[2-ethylhexyl]phthalate) commonly associated with plastic
packaging and films; three coal tar components (fluoranthene, pyrene, and phenol) commonly
associated with asphalt, tar, and other high molecular weight petroleum derivatives; and five
chlorinated solvents (1,1-dichloroethane, 1,1-dichloroethylene, tetrachloroethylene, trans-
1,2-dichloroethylene, and 1,2,4-trichlorobenzene), commonly used for cleaning fabrics and
metal surfaces. Another chlorinated solvent detected is methylene chloride. Chloroform is
* , 3-51 •
-------
Table 3-15. Overall Average Inorganic Domestic Pollutant Levels
Pollutant
Ammonia
Arsenic
Barium
Boron
Cadmium
Chromium(T)
Chromium(III)
Copper
Cyanide
Fluoride
Iron
Lead
Lithium
Manganese
Mercury
Nickel
Phosphate
Phosphorus
Selenium
Silver
Zinc .
Source: EPA (1991).
Table 3-16.
*
Pollutant
BHC
Bis(2-ethylhexyl) Phthalate
Chloroform
4,4-DDD
1,1-Dichloroethane
1,1-Dichloroethene
Endosulfan
Fluoranthene
Methylene Chloride
Phenols
Pyrene
Tetrachloroethylene
Trans-1 ,2-Dichloroethylene
1,2,4-Trichlorobenzene
Domestic Weighted
Average (mg/1)1
43.111
0.007
0.115
0.300
0.008
0.034
0.006
0.109
0.082
. 0.255
0.989
0.116
0.031
0.087
0.002
0.047
28.8
0.7
0.004
0.019
0.212
"
Overall Average Organic
•, *
Domestic Weighted
Average (mg/1)1
0.001
0.006
0.009
0.0003
0.026
0.007
0.002
0.001
0.027
0.010
0.0002
0.014
0.013
0.013
.
Minimum
7
.0004
.04
.1
.0006
.001
<0.005
<0.005
.01
.24
.0002
<.001
.03
.04
.0001
<.001
27.4
.7
.002
.0002
<.01
Domestic Pollutant
Minimum
.001
.00002
.00001 .
.00026
.026
.005 .
.002
.00001
.000008
.00002
.00001
.00001
.013
<.002
. '-
Maximum2
114
.088
.216
.42
.11
1.2
.007
.61
.37
.27
3.4
2.04
.031
.16
.054
1.6
30.2
.7
.005
1.052
1.28
Levels
Maximum2
.001
..022
.069
.0004
.026
.008
.002
0.001
.055
.029
<0005
.037
.013
.035
- A
' ' •;• "
1 Averages were weighted based upon the number of observations identified in each municipality.
2Mihimum and maximum values are single point values that define the range of data used. •
Source: EPA (1991). .
3-52-
-------
another chlorinated solvent present; however, it is a common by-product of drinking water
disinfection (see Subsection 3.3.3).
, . . • • \ • •
3.3.2 Potential Sources of Toxic Pollutants in Domestic Wastewater .
.-. "....-, • i
This subsection examines the potential sources of toxic pollutants present in domestic
wastewater. The discussion focuses on the disposal of household hazardous wastes and on
drinking water, which, although not regulated under the pretreatment program, may constitute
significant sources of toxic loadings to PQTWs! .
3.3.2.1 ' Household Hazardous Waste
Hazardous wastes are defined and regulated by EPA under the Resource Conservation
and Recovery Act (RCRA). However, RCRA's implementing regulations for the
management of hazardous wastes do not apply to hazardous wastes derived from
households. It has been shown, nevertheless, that even the small quantities of hazardous
waste discarded or discharged from households can collectively be of sufficient toxicity and
volume in municipal landfills and sewers to pose serious hazards to human health and the
environment (EPA, 1987b). Further, since household hazardous wastes may exhibit the
properties of regulated hazardous wastes, including toxicity, corrosivity, reactivity, or
ignitability, their discharge to POTWs can be a source of toxic pollutants.
The total quantity of household hazardous wastes discharged to POTWs is not known.
However, the specific types of toxic pollutants that are present in household hazardous
wastes and discharged to POTWs can be estimated based on an evaluation of the general
types of household products that may be disposed of via toilets and household drains. Table
3-17 lists products normally considered household wastes when discarded and the toxic
pollutants associated with these products. As indicated, a variety of common household
commodities contain toxic pollutants, including acids, bases, metals, and complex organic
compounds, including aliphatic and aromatic hydrocarbons, and chlorinated organic solvents.
The actual impacts on POTWs of the toxic pollutants associated with household
hazardous wastes is expected to be highly variable and dependent on a number of factors,
including proximity of households to the POTW treatment plant, type of treatment technology
in use, and the extent of local regulation and oversight of domestic discharges of hazardous
3-53
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Table 3-17. Hazardous Constituents of Common Household Commodities
Item
Examples of Potentially
Hazardous Ingredients
HOUSEHOLD CLEANERS
Toilet bowl cleaner
Trichloro-s-trianzinetrione
Sodium acid sulfate or oxalate or hydrochloric acid
Chlorinated phenols
Drain opener
Sodium hypochlorite
Sodium hydroxide
Trichlorobenzene
Potassium hydroxide
Hydrochloric acid
Trichloroethane
Laundry soap, bleach, dish-washing detergent,
bathroom cleaners, upholstery cleaners, floor
cleaners, other general purpose cleaners
Surfactants (LAS and other)
Ethoxylated alcohol
Methylene • chloride
Tetrachloroethylene
Sodium hypochlorite
Tetrachloroethane
Xylenols
Sodium hypochlorite
Phenols
Ammonia
Diethylene glycol
Polish (e.g., furniture, wood, metal, vinyl)
1,1,1-Trichloroethane
Petroleum distillates
Mineral spirits
Petroleum distillates
Oxalic acid
Denatured ethanol or isopropanol
Phosphoric acid
Floor finish
Diethylene glycol
Petroleum solvents
Ammonia
Air freshener
Alkyl phenoxy polyethoxy ethanol
Isobutane
Propane
3-54
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Table 3-17. Hazardous Constituents of Common Household Commodities
(continued) ,
Item
Examples of Potentially
Hazardous Ingredients
HOUSEHOLD CLEANERS (continued)
Other household (e.g., oven cleaner)
Sodium or potassium hydroxide
AUTOMOTIVE MAINTENANCE
Oil and transmission fluid (e.g., grease, hydraulic
fluid, motor oil, all purpose oil)
Petroleum distillates (petroleum hydrocarbons)
Lead
Engine treatment (e.g., transmission and motor oil
additives, fuel additives, carburetor cleaner)
Petroleum distillates
Mineral spirits
1,1,2-Trichloroethylene
Methylene chloride
Xylenes
Toluene
Antifreeze/coolant
Ethylene glycol
Methanol
Auto wax
Other auto (e.g., grease, solvents, rust solvents,
refrigerants)
Petroleum distillates
Toluene
Chlorinated aliphatic hydrocarbons
Potassium dichromate
HOUSEHOLD MAINTENANCE
Paint (e.g., latex, oil base, art and model paints)
Paint thinner and stripper (remover)
Toluene
Xylene
Methylene chloride
Halogenated aromatic hydrocarbons
Mineral spirits '
Toluene
Chlorinated aliphatic hydrocarbons
Esters
Alcohols
Chlorinated aromatic hydrocarbons
Ketones • ,
3-55
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Table 3-17. Hazardous Constituents of Common Household Commodities
(continued)
Item
Examples of Potentially
Hazardous Ingredients
HOUSEHOLD MAINTENANCE (continued)
Stain/varnish/sealant
Pentachlorophenols .
Methylene chloride
Mineral spirits
Petroleum
Methyl, and ethyl alcohol
Benzene
Lead
Glue (e.g., model, epoxy, general purpose)
Toluene
Methyl ethyl ketone
Acetone
Hexane
Methylene chloride
Asbestos fiber (asbestos cement)
Other maintenance (e.g., asphalt caulking, tar
paper)
Methylene chloride
Toluene
Trichloroethylene-
Benzene
Asbestos
Ketones
PESTICIDE AND YARD MAINTENANCE
Fertilizers
Concentrated potassium, ammonia,
nitrogen, phosphorus
Pesticides
Aromatic petroleum hydrocarbons
Petroleum distillates
Naphthalene
Xylene
Carbamates
Chlorinated hydrocarbons
Organophosphorus .
Urea
Uracil
Triazine base
Coumarin
Herbicides
Chlorinated phenoxys
Dipyridyl
Nitrophenols
3-56
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Table 3-17. Hazardous Constituents of Common Household Commodities
(continued)
Item
Examples of Potentially
Hazardous Ingredients
PESTICIDE AND YARD MAINTENANCE (continued)
Pet maintenance (e.g., flea and tick treatment
powders and liquids, flea and tick collars)
Carbaryl
Dichlorophene
Chlordane
Other chlorinated hydrocarbons
BATTERIES AND ELECTRICAL
Auto and flashlight batteries, solder, etc.
Mercuric oxide
Sulfuric acid
PRESCRIPTION DRUGS.
Diverse ingredients
SELECTED COSMETICS
Nail polish remover, hair spray, makeup remover,
dyes, etc. .
Aromatic hydrocarbon solvents
Acetone
Ethyl and butyl acetate
Toluene
Alcohols
Dibutyl phthalate .
OTHER
Pool chemicals, (acid, chlorine) hobby-related
•. activities, etc.
Sodium • dichloro-s-trianzinetrione
Source: EPA (1987b).
3-57
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wastes.16 Several local authorities have instituted programs to discourage the improper
disposal of household hazardous wastes, including disposal to POTWs. Many communities
• nave instituted separate collection programs for household hazardous waste. These
programs, coupled with public education awareness programs, have the potential to reduce
significantly the quantity of household hazardous waste disposed to POTWs and to municipal
landfills. Under these programs, a central collection point may be established for used oil,
automobile batteries, and other wastes.
. ', . '"" ,'••'' !V '•• ' • '
Table 3-18 shows the total number of household hazardous waste collection programs
by State in 1989. As indicated, 35 States have instituted over 600 household hazardous
waste programs. The- following examples are from several local programs:
' ' • "" ';•' '•''•"'." I. , • ' ' '
• The Massachusetts Water Resources Authority has initiated a public education
program to reduce the disposal of household hazardous wastes into sewer systems
(Spencer, 1990). • .. . .
• The town of Lexington, Massachusetts, has been holding 1-day collection programs
since 1981. Participation has increased every year since 1986. In 1989, a record 35
55-gallon drums of waste were collected.
• The State of Minnesota holds annual 1-day collections and maintains five permanent
collection facilities. Minnesota also operates a household hazardous waste hotline.
• The Seattle-King County area recently established an innovative mobile collection
unit, which travels to a different neighborhood in the metropolitan area every 2
weeks. . ' _ • ' ' ' •
3.3.2.2 Drinking Water
Another potential source of toxic pollutants in domestic wastewater is the community
drinking-water supply. It is estimated that domestic and public water use across the country
ranges from 100 to 150 gallons per capita per day, with a national average of 120 gallons per
capita-per day (Maddaus, 1987). Frequently, all of this water is discharged as wastewater,
less what is used for such purposes as lawn sprinkling and car washing. It is estimated that
the volume of wastewater from domestic and public sources ranges from 50 to 100 gallons per
capita per day (Hammer, .1975). Therefore, although drinking water might contain toxic
pollutants at levels below human health criteria, it still may represent' a significant source of
toxic pollutant loadings to POTWs. This is a particular concern where the effluent limits in a
16. It should be noted that the regulation of the disposal of hazardous household wastes is
outside the scope of the National Pretreatment Program.
3-58
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Table 3-18. Number of Household Hazardous Waste Collection
Programs in 1989
State
Alabama
Alaska
Arizona
California
Colorado
Connecticut
Florida
Hawaii
Idaho
Illinois
Indiana
Iowa •
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Missouri
Nebraska
New Hampshire
New Jersey
New Mexico
New York
North Carolina
Ohio
Oregon
Pennsylvania
Rhode Island
Texas
Vermont
Virginia
Washington
Wisconsin
Wyoming
Total
Number of Household Hazardous
Waste Collection Programs
1
10
' 2
107
3 • "•
34
61
9
2 •-•'
' . 1 ' '. •
4
*
11
•"'-..- 2 '•
2 .-._.-
'5
91
25
. . . ' 55
1
3
. 19
.31
3
56
4 • ,
1 .
3 ' ':'
5
5
2
5 • - .
9
41
14
. _i
628
Source: EPA (1990b).
3-59.
-------
POTW's NPDES pennit are based on water quality criteria or sludge criteria that may well be
more restrictive than the human health criteria on which me driffing water standards are
based. Such would be the case when water quality or sludge criteria are based on protection
of other species (e.g., irigestion by fish of pollutants that bioaccumulate).
The Safe Drinking Water Act (SDWA) Amendments of 1986 require EPA to establish
regulations to protect human health from contaminants in drinking water. Under the SDWA,
EPA must establish maximum contaminant levels (MCLs) and maximum contaminant level
goals (MCLGs) for 83 specified contaminants considered to be of significant risk to human
health. MCLs are established as close as possible to MCLGs after consideration of
available water treatment technologies and cost.
. ,, , ' •'< . 'i ','/,;•-, ' ',',",, ,'" •'
In addition, the SDWA mandates that MCLs and MCLGs be established for 25
additional contaminants every 3 years, to date, 32 contaminants have been regulated (see
Table 3-19). MCLs'or appropriate treatment technologies for the other contaminants are
being developed.
Although toxic pollutants found in source waters will be treated as mandated by the
SDWA Amendments, the collective loadings of these pollutants in drinking water may be
significant for the POTWs that ultimately receive this water. Furthermore, under certain
circumstances, treated drinking water may contain pollutants mat are not regulated .under the
SWDA and thus not removed. When discharged, these pollutants may result in increased
loadings of toxics to POTWs.
' For example, treated waters that meet existing standards at the point of entry into the
distribution system may be corrosive and cause leaching of toxic pollutants, such as lead,
copper, and zinc, into the water, during transmission'and distribution. (Ironically, zinc
orthophosphate, a popular lead corrosion inhibitor that is added to drinking water systems,
has the potential to raise zinc levels in POTW influents.) If the drinking water purveyor
reduces the corrosivity of the water supply, the improvement in effluent and sludge quality
may be dramatic. In New Jersey, for example, the Cumberland County Utilities Authority
achieved a copper reduction in sludge from 7,000 mg/kg to i,200 mg/kg as a result of
corrosivity reduction in the water supply (New Jersey DEP, 1990).
5.3.3 Evaluation of Domestic Loadings of Toxic Pollutants
This subsection demonstrates the potential significance of toxic pollutant loadings to
POTWs that are due to domestic discharges. To estimate the potential impact' of domestic
3-60
-------
Table 3-19.. Contaminants Required to be Regulated Under the
1986 SDWA Amendments and Existing MCLs*
Contaminant
Volatile Organic Chemicals
Benzene
Carbon Tetrachloride
Chlorobenzene
Dichlorobenzene
Ethylbenzene
1,2-Dichlorethane
1,1-Dichloroethylene
• Cis-l,2-Dichloroethylene
Trans-l^-Dichloroethylene
Methylene Chloride
Tetrachloroethylene
Trichlorobenzene
1,1, 1-Trichloroethane
Trichloroethylene
Vinyl chloride
Microbiology and Turbidity
Giardia lamblia .
Legionella
Total Coliforms
Turbidity
Viruses
MCL
O.OOS mg/1
0.005 mg/1
**
**
**
0.005 mg/1
0.007 mg/1
**
**
**
• **
**
0.20 mg/l
0.005 mg/l
0.002 mg/1
Treatment to
<99.9% removal
Treatment to
<99.9% removal
<1/100 ml
1 ntu*** (up
to 5. ntu)
Treatment to
<99.9% removal
Contaminant
Inorganics
Aluminum
Antimony
Arsenic
Asbestos
Barium
Beryllium •
Cadmium
Chromium
Copper .
Cyanide
Fluoride
Lead ;
Mercuiy
Molybdenum
Nickel
Nitrate (as N)
Selenium
Silver
Sodium (no MLC monitoring,
reporting only)
Sulfate
Thallium
Vanadium
Zinc
MCL
** .
**
.05 mg/1
**
1.0 mg/1
** ' ' -
0.010 mg/l
0.05
**
**
1.4-2.4 mg/l + .
(ambient temp.)
.05 mg/l
0.002 mg/l
**
**
10 mg/l
0.01 mg/l
0.05 mg/l
** • .
**
**
**
**
**
Some MCLs were in the process of being revised as the analysis was being performed.
Not yet promulgated
*** ntu = nephelometric turbidity unit
Source: Pontius (1990) , - '
3-61
-------
Table 3-19. Contaminants Required to be Regulated Under the
1986 SDWA Amendments and Existing MCLs* (continued)
Contaminant
MCL
Contaminant
MCL
Organics
2,4-D
Adipates
Alachlor
Aldicarb
Aldicarb Sulfone
Aldicarb Sulfoxide
• Atrazinc
Carbofuran
Chlordane
Dalapon
Dibromochloropropane (DBCP)
DIbromomethane
1,2-Dichloropropane
Dinoseb
Diquat
Endothall
Endrin
Epichlorohydrin
Ethylene Dibromide (EDB)
Glyphosate
Hcptachlor •
Heptachlor epoxide
HexacbJorocyclopentadiene
Lindane
Methoxychlor
Pentachlorophenol
Phthalates
Pichloram
Polychlorinated
Biphcnyls CPCBs)
0.1 mg/1
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
0.0002 mg/1
**
**
**
**
**
**
0.0004 mg/1
0.1 mg/1
**
**
**
**
Organics, continued
Polynuclear Aromatic
Hydrocarbons (PAHs)
Simazine
Styrene
2,3,7,8-Tetrachlorodi-
benzodioxin (dioxin)
Trihalomethanes
Toxaphene
2<4,5-TP (Silvex)
1,1,2-Trichloroethane
Vydate .
Xylene
Radionuclides
Beta Particle and Photo
Radioactivity
Gross Alpha Particle
activity •
Radium-226 and -228
Radon
Uranium
*l|c
**
**
0.10 mg/1
0.005 mg/1
0.01 mg/1
.**
**
**
4 mrem-(annual dose
equivalent)
15pCi/l
5pCi/l
**
* Some MCLs were in the process of being revised as the analysis was being performed.
** Not yet promulgated .
*** ntu = nephelometric turbidity unit
3-62
-------
loadings of toxic pollutants, EPA postulated the existence of a POTW receiving .only
domestic wastewater. This situation is based on a conservative assumption, since in most
cases .even those industrial discharges treated to remove toxics will have higher toxic
pollutant concentrations than domestic sewage. Thus, if a POTW receiving only domestic
wastewater is affected by the concentration of toxics in domestic sewage, a POTW receiving
mixed industrial and domestic waste would be affected at least as much.
The hypothetical POTW is assumed to receive domestic sewage with the toxic pollutant
concentrations listed in Tables 3-15 and 3-16 (i.e., trunk line monitoring data from 15
municipalities). The assumed effluent limits in hypothetical POTWs National Pollutant
Discharge Elimination System (NPDES) permit were based on compliance with EPA water
quality criteria. The standards applied were chronic criteria for the protection of aquatic life,.
with the exception of arsenic, for which human health protection criteria (assuming water and
fish consumption) were used. Two sets of NPDES effluent limits were used: one that
assumes no dilution of the POTW effluent is allowed in the receiving water, and another that
assumes that up to 50-percent dilution of the effluent is allowed. . ,
Given the influent concentrations in Tables 3-15 and 3-16 and the two. sets of NPDES
effluent limits, EPA calculated the necessary POTW removal efficiencies for each pollutant
(see Table 3-20). In those cases where effluent limits were greater than domestic (or
assumed influent) concentrations, POTW removal efficiencies are immaterial, and the
necessary removal efficiency is listed as N/A.
As Table 3-20 indicates, water quality criteria can be met for the five organic
compounds, nickel, chromium, and selenium under both effluent limit scenarios. For zinc, 48-
percent removal would be necessary for a POTW to comply with water quality criteria;
domestic concentrations are less than tiie effluent limits for zinc, assuming 5p-percent
dilution was available. For the rest of the metals except zinc, significant and likely
unachievable removal efficiencies would be required for. the hypothetical POTW to meet water
quality criteria, even with 50-percent dilution of the effluent. Because POTW removal
3-63
-------
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efficiencies are highly variable (see Chapter 4), the presence of toxics, particularly metals, in
domestic wastewaters could be significant17
• _•-..«,' '> ,.•''. '• _• •
In order to evaluate the proportion of total allowable toxic pollutant loadings to POTWs
that could be attributed to domestic sources, EPA evaluated local limits submissions for 25
POTWs in EPA Region VL As shown in Table 3-21, domestic loadings of several pollutants
accounted for more than 50 percent of allowable loadings at certain POTWs. Some of these
POTWs experienced loadings of certain pollutants (copper, silver, cyanide, phenols, and zinc)
at more than 75 percent of total allowable loadings. .
3.4 OTHER SOURCES OF Toxic POLLUTANTS
Toxic pollutants may also be discharged to POTWs from sources other than industrial,
commercial, or domestic discharges. This section discusses the potential types and
quantities of toxic pollutants associated with these sources, including storm water, collection
system infiltration/inflow, and RCRA and Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) sources. .
3.4.1 Storm-Water Sources
. POTW collection systems are classified either as combined or separate, based on
whether they receive storm water. In separate systems, two distinct collection systems are
provided, one for waste water (both industrial/commercial and domestic), which discharges to
the POTW, and the other exclusively for storm water, which is discharged directly to
receiving waters. Although more costly to construct, separate POTW collection systems
minimize hydraulic loads to treatment facilities and avoid mixing storm water with domestic
and industrial wastewater. Control authorities in areas with separate systems usually have
ordinance requirements that prohibit the discharge of storm water to the sanitary system.
Some storm water will, however, find its way to the sanitary system through illegal
discharges (such as downspout connections and sump pump .discharges). The extent of
17. It should be noted that the necessary removal efficiencies for the toxic metals may be
understated because the domestic sewage average concentrations most likely represent
total metals concentrations, and the EPA water quality criteria represent only the acid-
soluble portion of the metal.
3-65 .
-------
Table 3-21. Summary of Local Limit Submissions
for 25 POTWs in Region VI
Pollutant
Arsenic
Ofltfminm
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Zinc
Cyanide
Chromium (hex)
Chromium (tri)
Phenols
1 ,4-Dichlorobenzene
Trichloroethylene
Bis(2-ethylhexyl)
phthalate
Tetrachloroethylene
Thallium
Beryllium
NH3
Tin
Number of POTWs
Developing Local
Limits
25
25
25
25
• 25
25 .
25
.15
25
25
23
2
1
20
2
2
2
1
1 .
4
. 5
1
Number of POTWs
Where Domestic
Load Accounted for
>50%ofthe
Allowable Load
0
1
2
2
2
1
3
0
4
14
1
0
0
.1
0
0
0
0
0
0
0
0
Number of POTWs
Where Domestic
Load Accounted for
>75%ofthe
Allowable Load
0
0
0
1
0
0
0
0
2
6
1
0
0
1
o
0
0
0
0
0
0
0
Source: EPA (1990a)
.3-66 ,
-------
these contributions will depend on the surveillance, monitoring, and enforcement actions of
the control authority.18 >
Combined collection systems use a single conveyance system to transport wastewater
and storm water. To avoid hydraulic overloading of the treatment facility, or the collection
system itself, combined systems are usually equipped with regulators. These regulators,
dispersed throughout the collection system, release water from the collection system when a
predetermined flow rate in that part of the system is exceeded. Discharges from regulators,
commonly referred to as combined sewer overflows (CSOs), are usually directed to a
receiving stream. • ,
'""**' • - • '
The loadings of toxic pollutants from storm-water runoff to a combined collection system
and its receiving POTW may be significant. This would be particularly true if storm-water
runoff representing the "first flush" is not discharged through a combined sewer overflow but
instead is received at the. POTW treatment plant19
3.4.1.1 Combined Sewer System Estimate .
EPA OWEP estimates that there are about 1,200 combined sewer systems in the
United States.20 It is estimated that at least 240 control authorities implementing approved
pretreatment programs maintain combined sewer collection systems that collect storm-water
runoff from areas within their service areas (EPA, 1990c; NEWPCA, 1989). As shown in
Table 3-22, the total number of control authorities with CSOs is relatively small compared to
the total number of control authorities nationwide.
18. In November 1990, EPA promulgated regulations to control storm-water discharges from
industrial activities and separate storm sewer systems serving municipalities with
populations of 100,000 or more (55 FR 47989; Nov. 16, 1990). These regulations
establish NPDES permit application requirements that require in part a description of a
proposed management program to reduce, to the maximum extent practicable, pollutants
from storm-water discharges to municipal systems.
19. In September 1989, EPA issued a CSO Control Strategy (54 FR 37370; September 8,
1989). The objective of the CSO Strategy is to ensure regulation of CSO discharges to
receiving waters. Part of this strategy encourages the use of the POTW pretreatment
program as an additional control measure to reduce the amounts of pollutants present in
combined sewers during storm events.
20. National CSO Control Strategy memorandum, August 10, 1989.
3-67
-------
Table 3-22. Pretreatment Programs With Combined Sewer Overflows (CSOs)*
EPA Number of Control
Region State Authorities
I MA
NH
ME
RI
CT
VT
K • NJ
NY
PR
m DE
DC
MD
PA
VA
wv ' •
IV FL
. GA
KY .
. TN
• NO'
sc
AL
MS
V IL
IN
; MI
MN
OH
WI
VI AR
LA
NM
OK
IX
vn IA
KS
MO .
NE
38
12
15
13
NA .
, NA
22
56
1
5
1
15
82
23
7
39
39
64 '
77
121
58
•NA
NA
45
45
110
6
97
23
28
12
4
19
61
20
15
43
NA
Number of Control
Authorities
With CSOs
15
5
9
3
NA
NA
9
28
0
" 1
1
2
16
3
7
0
5
8
5
0
0
NA
NA
16
39
29
1
34
1
1
0
ND
0
0
ND
ND
ND
NA
3-68-
-------
Table 3-22. Pretreatment Programs With Combined Sewer Overflows (CSOs)*
(continued) .
EPA
Region
vm
rx
X
Number of Control
State Authorities
CO
MT
ND
SD
m
WY
AZ
CA
ffl -. '
NV
AK
ID
OR
. . WA
Total .
27
6
3 .
2
13
3
15
100
1
5
2
13
20
S
1,434
Number of Control
Authorities
With CSOs
1
ND
0
ND
0
0
0
1
0
0
0
ND
ND
ND
240
NA = Not applicable; State-implemented pretreatment program.
ND = No data available.
*Limited data are available; estimates based on information submitted to EPA in response to
the National CSO Control Strategy. . ,
Source: EPA (199Qc) and NEWPCA (1989).
3-69
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3.4.1.2 Characterization of Storm Water
Storm-water runoff collected by combined sewer systems may contain toxic pollutants
that may ultimately be discharged into POTWs. Toxic pollutants in storm-water runoff come
primarily from urban roadways and parking lots, runoff from industrial facilities, agricultural
runoff of pesticides, and ah- pollutants washed to the ground by precipitation.
The most complete study to determine types of pollutants found in storm-water runoff
was conducted by EPA during the Nationwide Urban Runoff Program (NURP). In 1978, EPA
initiated NURP to determine the nature, cause, and severity of urban runoff problems and to
identify opportunities for controlling these problems. The program, conducted by Woodward
and Clyde, provided information and methodologies for water quality planning efforts. It
consisted of 28 separate .projects sampling and analyzing storm water runoff in specific types
of watersheds. Data from the NURP study provide insight on what can be considered
background levels of pollutants in storm-water runoff from residential, commercial, and light
industrial land use areas. . NURP data were used ras the basis of proposed storm-water
regulations published by EPA on November 16, 1990 (55 FJ?" 47990)'.
To assess the pollutant loadings of storm-water discharges exclusively, NfjRp avoided
any sites where combined sewers existed. No national .studies have been conducted to
measure how much storm water is actually discharged into combined sewers, so pollutant
, • " . , '•,,'" ; „ ','•',' '"":! ''' :!:•!"'" • !i'!!!lih' ''i!!i '''"'I"'1"',';' '"" •'••' '" •»', " •, '! 1 "i i1!'",! '"„„"','i,' 'i.,'1'1', ',,' ' ,' " '''i1 •'':,'
loadings from storm water mat reach POTWs cannot be estimated on a national level. It can
be assumed, however, that the types of toxic pollutants identified in storm-water runoff in the
NURP study would be present in combined sewer flows and, thus, discharged to POTWs.
Table 3-23 summarizes.the results of the NURP priority pollutant sampling program.
Seventy-six priority pollutants; comprising 15 inorganic and 61 organic compounds, were
detected in the runoff samples. Toxic metals were, by far, the most prevalent priority
pollutants found in urban runoff. All 15 priority pollutant inorganics (12 metals plus cyanide,
fluorine, and selenium) were detected. All but mercury, silver, thallium, and fluorine were
detected in at least 10 percent of the samples. Copper, lead, and zinc were the most
prevalent, being detected in over 90 percent of the samples. Other inorganics frequently
detected included arsenic, chromium, cadmium, nickel, and cyanide.
Organic pollutants were generally detected less often in urban runoff samples and were
generally found at lower concentrations than inorganic pollutants. Sixty-one (of 106 organic
priority pollutants) were detected in at least one urban runoff sample.The plasticizer bis(2-
-: i! , . '", " ,. •!' '•''' " , •» .• '!"•''! '• "
3-70
-------
Table 3-23. Frequency of Detection of Priority Pollutants in Urban Runoff
During the Nationwide Urban Runoff Program
Constituent Frequency of Detection
'• • (percentage of samples)
Lead 94
Zinc 94
Copper 91
Chromium ' 58
Arsenic . 52
Cadmium 48
Nickel 43
Cyanide 23
Phthalate, Bis (2-ethylhexyl) 22
Alpha-Hexachlorocyclohexane 20
Alpha-Endosulfan . , ' ' 19
Phenol, Pentachloro 19
Chlordane . . .17
Fluoranthene 16
Gamma-Hexachlorocyclohexane 15
Pyrene 15
Phenol 14
Antimony . .13
Phenanthrene . 12
Beryllium 12
Methane, Dichloro 11
Selenium . 11
Phenol, 4-Nitro 10
Chrysene . ' 10
Mercury 9
Methane, Trichlord . 9
Naphthalene . . 9 .
p-Chloro-m-Cresol 8
Silver .7
Anthracene . 7
Aldrin 6
bieldrin 6
Heptachlor 6
Thallium .. 6
1,1,1-Trichloroethane . 6
Trichloroemylene 6
Ethyl Benzene 6
Phthalate, Diethyl 6
Phthlate, Di-N-Butyl 6
Ph'thlate, Di-N-Octyl 6
Phthlate. Butyl Benzyl 6
3-71
-------
Table 3-23. Frequency of Detection of Priority Pollutants in Urban Runoff
During the Nationwide Urban Runoff Program (continued)
Constituent
Frequency of Detection
(percentage of samples)
Benzo (a) Pyrene
Beta-Hexachlorocyclohexane
Methane, Trichlorofluoro
Ethylene, Tetrachloro
Benzene
Benzene, Chloro
Benzo (b) Fluoranthene
Ethene, 1,2-Trans-Dichloro
Benzo(a)anthracene
Isophorone
Methane, Tetrachloro
Ethane, 1,1-Dichloro
Toluene
Benzo(k)fluoranthene
Heptachlor Epoxide
Ethane, 1,1,2-Trichloro
Ethane, 1,1 ^^-Tetrachloro
Ethene, 1,1-Dichloro
Propene, 1,3-Dichloro
DDT
PCB-1260
Methane, Chlorodibromo
Methane, Dichlorobromo
Methane, Tribromo
Ethane, 1,2-Dichloro
Propane, 1,2-Dichloro
Phenol, 2-Chloro
Phenol, 2-Nitro
m-Cresol, p-Chloro
Phthalate, Dimethyl
Benzo (g,h,i) Perylene
Dibenzo (a,h) Anthracene
Fluorcne
Ideno(l,2,3-c,d)Pyrene
6
5
5
5
5
5
5
4
4
3
3
3
3
3
2
2
2
2
2
1
1
1
1
1
1
1
1
1-
1
1
1
1
1
1
Source: EPA (1983).
3-72
-------
ethylhexyl) phthalate, found in 22 percent of the urban runoff samples, was detected most
frequently, followed by the pesticide alpha-hexachlorocyclohexane (alpha-BHC), detected in
20 percent of the samples.
. In summary, toxic pollutants reach POTWs via storm-water runoff collected by
combined sewers, although the quantities of toxic pollutants cannot be estimated with
currently available data. The most common storm-water runoff pollutants found in, the NURP
study were toxic metals, such as lead, zinc, copper, chromium, arsenic, cadmium, nickel, and
cyanide.
3.42 Infiltration/Inflow Sources
Infiltration and inflow may also contribute a diverse load of toxics to POTWs..
Infiltration is the passage of ground water into a collection system through breaks and leaks
in the system. Inflow, the uncontrolled entrance of water into the system from surface
sources, typically occurs when surface water passes over unsealed manhole access points.
Pollutant loadings resulting from inflow reflect the characteristics of the storm water
entering the system (see Subsection 3.4.1). Pollutant loadings resulting from infiltration
reflect any contamination of the ground water in the area where the infiltration is occurring. Li
areas where the ground water is uncontaminated, the problem will simply be one of additional
hydraulic load. In the vicinity of hazardous waste sites or other ground-water contamination,
infiltration may also constitute a source of toxic pollutants. Because infiltration is difficult to
detect and is rarely analyzed for the presence of pollutants, the extent of infiltration as a
source of toxics is generally unknown. However, there have been some instances in which
the infiltration of toxics has been found to be a significant source of toxic pollutants. These
instances are discussed below.
The Niagara Falls, New York, area provides an example of how ground water
contaminated by hazardous waste can affect the sanitary sewer system through inflow and
infiltration. Disposal of hazardous wastes in the Love Canal area has caused extensive
contamination of ground water in the area, which is served by a separate sanitary and storm-
water collection system. As a result, there is continuous infiltration of pollutants into the
sanitary sewer system. In addition, sufficient contamination occurs in the storm water so
that a portion of the dry weather flow in the storm-water sewer system is required to be sent
to the POTW for treatment.
3-73
-------
Another'example of toxics entering a collection system through infiltration can be found
in Largo and Hollywood, Florida (Hazen and Sawyer, 1990): Diazmon, apparently from
agricultural use, has been detected consistently throughout the collection systems. There are
no known point source discharges, but it is possible for inflow to occur through unsealed
manholes or other such methods. Although the measured concentrations are low (~1 part per
billion [ppb]), the LDso for Cerodaphnia duba is 0.35 ppb. As a result, both cities are
currently unable to comply with their effluent bioassay limitations. Both cities are conducting
tests to verify that contaminated ground water is the. cause of the contamination, as well as
exploring several treatment options.
*,',,' ,'.„'' ' ;li i ... • I" I ; ,.:•,' ',!, •'!',. , '...'., • i ,l
The City of BlackweU, Oklahoma, also has found that infiltration of ground water into the
sewer system causes POTW effluent toxicity (City of BlackweU, 1990). Specifically,
monitoring by the City of BlackweU showed that cadmium and zinc were entering a specific
section of the sewer collection system, .via ground water. Remediation of the sewer collection
system to stop infiltration has reduced toxicity of the POTW effluent.
3.4.3 Waste Haulers
A common method for the disposal of liquid wastes from domestic, commercial, or
industrial sources not connected to a POTW collection system is to have them hauled to a
POTW. The types of wastes that can be hauled to POTWs range .from septic tank pumpings
to industrial process wastewater. The control over the discharge of hauled'wastes varies
among POTWs.21 :
,: S1!.
The only data available that estimate the prevalence of the discharge of hauled wastes
are contained in PASS. According to PASS, 47 percent of the POfWs accept hauled septage
(material removed from residential septic tanks during periodic maintenance), 3.4 percent
accept hauled landfill leachate, less than ! percent accept hauled RCRA/CERCLA site
wastes/leachate, and 1.5 percent accept hauled hazardous waste.22
21 Recent revisions to the General Pretreatment Regulations (55 FR 30082; July 24, 1990)
require increased control over waste haulers. Specifically, the regulations forbid the
discharge of trucked or hauled wastes to sanitary sewers except at points designated by
the Control Authority (40 CFR 403.5[b][8]).
22. The percentages from PASS are based on the results of audits of 530 POTW
pretreatment programs. . . •
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Limited data are available at the national level that characterize the types and
quantities of toxic pollutants contained in hauled wastes. However, EPA recently collected
data from several POTWs and provided the results in the report entitled, Supplemental
Manual on the Development and Implementation of Local Discharge Limitations Under the
Pretreatment Program: Domestic/Commercial Loadings Removal Efficiency Estimation
(EPA, 1991). Overall average pollutant levels in septage hauler loads, obtained from nine
municipalities in seven Regions, are presented in Table 3-24. ;
Table 3-24. Summary of Pollutants Detected in Septage Hauler Wastes
' ' . Septage
Pollutant Average (mg/l)
Acetone
Benzene
Ethyl Benzene '
Isopropyl Alcohol
Methyl Alcohol
Arsenic
Barium
Cadmium
Chromium (T) ;
Cobalt
Copper
Cyanide
Iron
10.588
0.062
0.067
14.055
15.84
0.141
5.758
0.097
0.490
0.406
4.835
0.469
39.287
Septage
Pollutant Average (mg/1)
Methyl Ethyl Ketone
Methylene Chloride
Toluene -.
Xylene
Lead
Manganese
Mercury .
Nickel.
Silver
Tin
, . Zinc
3.650
0.101
0.170
0.051
•,
1.210
6.088
0.005
0.526
t).099
0.076
9.971
Source: EPA (1991). .
Metals identified at the highest average levels were iron (39.287 mg/l), zinc
(9.97 X mg/1), manganese (6.088 mg/l), barium (5.758 mg/1), and copper (4.835 mg/l). As
indicated, organics identified at the highest average levels are methyl alcohol (15.84 mg/l),
isopropyl alcohol (14.055 mg/l)., and acetone (10.588 mg/l). Pollutant concentrations in
septage (Table 3-24) are higher than their corresponding concentrations in
residential/commercial wastewater (Tables 3-15 and 3-16) because septic systems
accumulate, and therefore concentrate, wastes before the wastes are hauled to a POTW.
POTWs whose influents comprise a relatively large proportion of hauled septage may find
that these wastes contribute significant loadings of certain pollutants.
3-75
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It should be noted that POTWs that accept hazardous wastes by truck, rail, or
dedicated pipe are considered to be hazardous waste treatment, storage, and disposal
facilities (TSDFs) and are subject to regulation under RCRA. Under RCRA, mixtures of
domestic sewage and other wastes, including those considered hazardous, that commingle in
the POTW's collection system prior to reaching the property boundary of the POTW are
excluded from RCRA regulation. Hazardous wastes delivered directly to the POTW by trucks
rail, or dedicated pipeline do not fall within the exclusion and may only be accepted by
POTWs that comply with the applicable RCRA requirements for TSDFs.
Hazardous wastes delivered to POTWs by truck, rail, or dedicated pipe may vary in
quantity and characteristics from load to load. EPA did not analyze me constituents of hauled
hazardous wastes or the extent to which they contribute to toxic pollutant loadings at
POTWs for purposes of this report. The Rock Creek Waste Treatment Facility in
Independence, Missouri, is an example of a facility that accepts hauled hazardous waste. In
1989, the facility received wastes totaling more than 81 million gallons from nine firms. An
example of the leachate from a secure hazardous waste landfill received by the Rock Creek
WTF from the Peoria Disposal Company is shown below.
Parameter
Concentration (mg/1)
Total Phenols
Benzene
1,1-Dichloroethane
1,2-Dichloropropane
Ethylbenzene
Toluene
Trans-1,2-Dichloroethylene
1,1,2-Trichloroethane
2,4-Dimethylphenol
Manganese
Nickel
Trichloroethylene
2-Methylphenol
2.5
.0.065
0.098
0.17
3:5
21.0
0.18
0.024
0.59
2.7
2.3
0.52
4.4
3.4.4 RCRA and CERCLA Activities
This section addresses the potential impacts that wastewaters from RCRA corrective
actions, CERCLA remediations, underground storage tank (UST) cleanups, and municipal
landfills may have on discharges of toxic pollutants to POTWs.
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3.4.4.1 Background
Congress and EPA have attempted to minimize the potential degree of overlap between
RCRA and CWA statutes and in subsequent rulemakings—hence, the domestic sewage
exclusion.and the wastewater treatment tank exemption. The exclusion and exemption were
designed to limit overlap while providing that wastewaters would be treated sufficiently to
protect our Nation's waters. The practical impact of the exclusion and exemption was to
place the responsibility for wastewater effluent quality on EPA, State, and local water quality
managers. Thus, for example, of the 8.9 million tons of hazardous waste managed in the
State of New Jersey, approximately 7 million tons (or 78.7 percent) are wastewaters
managed through RCRA-exempt processes (EPA, 1985).
«• ( :
Over the last 6 years, since the passage of the Hazardous and Solid Waste
Amendments (HSWA) of 1984, increasingly more attention has been placed on the perceived
increases in intermedia transfer of wastes from the land to the water media. Prior to HSWA,
concerns centered on intermedia transfers from water to land, most significantly the growing
quantities of hazardous sludges generated as a result of CWA wastewater treatment
requirements. HSWA included several provisions that, taken together, were designed to
limit the Nation's reliance on land disposal. These provisions included:
• The Loss of Interim Status Provision—Required compliance with ground-water
monitoring, closure, post-closure, and financial responsibility guidelines by a certain-
date, thereby resulting in me closure of many interim status land disposal facilities.
• The Land Disposal Restrictions Program—Prohibited land disposal of hazardous •
wastes unless certain treatment levels were achieved.
• Enhanced Treatment Design Requirements for Surface Impoundments and Landfills—
Required new and old landfills and surface impoundments to meet certain liner and
leachate collection requirements.
• The Corrective Action Program—Enhanced the coverage of corrective action
requirements for ground-water, soil, surface water, and air release remediation at
interim status and permitted facilities for all solid waste management units. Subtitle
I of the HSWA authorized an UST program, including corrective action requirements
for UST releases. -
These provisions were designed to decrease industry's reliance on surface impoundments,
landfills, and other land-based units for hazardous waste treatment, storage, and disposal,
thereby decreasing the likelihood of future ground-water contamination. Then- effect could be
the possible diversion of greater amounts of waste to POTWs, which would create a greater
regulatory burden for the local pretreatment programs.
3-77
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Another source of discharges to POTWs comes from cleanup sites regulated under
CERCLA, also known as Superfund. The Superfund remedial action program, like the RCRA
corrective action program, could potentially result in increased discharges to POTWs. •.
" » „ i'1' , . ' ",,„,.;.
, ;j|ii ' • : .,•';' '; '; • ' .,![, . . i ....
As noted previously, many activities conducted as a result of RCRA and CERCLA
initiatives can affect the methods by which wastewaters are managed. These actions may
have an impact on the volumes or quality of wastewaters discharged to POTWs. Those
RCRA and CERCLA programs that may result in appreciable increases in the quantity or
quality of wastewaters are summarized below.
3.4.4.2 RCRA Corrective Actions and CERCLA Remedial Actions
Both the RCRA Subtitle C corrective action program and CERCLA remedial action
program could result in increased discharges to POTWs as a result of cleanup activities.
While no firm estimates are available of the quantity of4 wastewaters that is or may be
discharged as a result of these programs, the use of a POTW is a potential treatment
alternative for such wastewaters. EPA's Pretreatment Audit Summary System, for example,
lists five pretreatment authorities that acknowledged the receipt of RCRA/CERCLA
corrective/remedial action wastes by truck, rail, or dedicated pipeline. In all likelihood, a still
larger number of POTWs received wastewatersfrom RCR^/CERCLX cleanup actions
discharged directly to then* collection systems.
EPA estimates that 5,700 hazardous waste treatment, storage, or disposal facilities are
currently subject to RCRA Subtitle C and are potentially subject to the corrective action
requirements. Together, these facilities are likely to have as many as 80,000 solid waste
management units. EPA also estimates that up to 1,700 facilities will require ground-water
remediation (55 FR 30862).
Currently, 1,189 facilities are on the Superfund National Priorities List (NPL). EPA
estimates that 37 percent of Fund-lead sites will involve either ground-water or surface-
water restoration (EPA, 1988b). Restoration activities include pumping and treating ground
waters from contaminated aquifers. The Seymour Recycling Corporation (SRC) site, to cite
one example, is a 14-acre area 2 miles southwest of Seymour, Indiana. From about 1970
through 1980, SRC operated a processing center for waste chemicals in a predominantly
agricultural area. Ground water in the vicinity of the site is contaminated. The primary
contaminants of concern in the ground water include volatile organic chemicals (i.e.,
trichloroethylene, benzene, and toluene), other organics, and heavy metals. The selected
' ' • 3-78
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remedial alternative for the site is the implementation of a plume stabilization system that
will extract and treat a total of approximately 102 million gallons of contaminated ground
water. The treated ground water is sent to the Seymour Wastewater Treatment Plant, a
POTW with an actual flow of 3.4 mgd (EPA, 1987a). It is estimated that 0.4 mgd of treated
ground water will be discharged to the POTW over a 12-year period.
3.4.4.3 UST Cleanups
EPA estimates that nearly 850,000 facilities and approximately 1.7 million tanks are
subject to the Agency's .UST program (EPA, 1988c). Of these, the Agency estimates that
about 21 percent are leaking from either the tank, the fill system, or the discharge system.
Leaking USTs can have a direct and indirect impact on POTWs. As discussed in Subsection
3.4.2, sanitary and storm sewer collection systems can become contaminated through
infiltration of contaminated ground water (EPA, .1987c). Perhaps of greater significance,
however, is the impact of the volumes of waters that may be discharged to POTWs as a
result of UST cleanup actions. These contaminated waters can come from the following
sources: contaminated ground water, contaminated storm water, wastewaters generated
from tank-cleaning operations, and contaminated water resulting from product recovery
operations.
While the total median release volume from USTs reaching ground water is 4,500
gallons per incident, the volume of ground water eventually contaminated, and needing
remediation, is far greater (EPA, 1988c). The Volume of discharges generated from cleanups
-, .•.'•••
varies as a result of site-specific factors, such as the size of the release and the depth to
ground water. However, EPA estimates that the typical flow of wastewater discharge as a
result of UST cleanups is in the range of 3 to 20 gallons per minute, or about 4,000 to 30,000
gallons per day (EPA, 1989a).
The major constituents present in discharges from UST cleanups depend upon the
materials stored in the tanks. The primary pollutants found in cleanups of gasoline USTs, for
example, include benzene, toluene, xylene, and ethylbenzene.
The U.S. Coast Guard Air Station in Traverse City, Michigan, was in the process of
installing a new fuel farm system in 1979 when soil contamination was discovered in a jet fuel
storage area. Subsequent investigations found that the ground water was contaminated. The
Coast Guard found that the apparent source of the contamination was a high-octane aviation
fueling station failure 11 years earlier, which resulted in a 2,000 gallon release of product over
3-79
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a' 12-hour period (EPA, 1987c). Contaminated soil was removed and a containment system
consisting of seven extraction wells was constructed to block further plume migration. Water
•pumped from the extraction well system was piped to a carbon treatment system, where
carbon reactors were specified to reduce the levels of benzene and toluene in the water to .
less than 1 microgram per liter. The treated UST wastewater is then discharged at a rate of
200 gpm to the Traverse City POTW, a pretreatment POTW with an actual flow of 3.27 mgd
(and a design flow of 8.5 mgd).
3.4.4.4 Municipal Solid Waste Landfills
This subsection analyzes the potential effects of discharges from municipal solid waste
.landfills (MSWLFs) to POTWs. Two. concerns are addressed: (1) treatment of generated
leachates, and (2) contaminated ground waters discharged upon treatment.
EPA's proposed criteria for MSWLFs, which should be finalized in 1991, would require
new and existing MSWLFs to institute practices to control leachate collection and surface
water runoff. Most new landfills and lateral expansions of existing landfills would be required
to install liners and leachate collection systems. (Existing units would not be required to
retrofit with liners and leachate collection systems, however). All landfills would be required
to construct run-on/runoff controls for surface water. EPA expects that with the imposition of
these controls, more leachate will be collected and need to be treated. EPA's Report to
.. V ' •' ;. '" ''.' • ' i'. •' V "•••'•'.'" Mi .;B JvWairt U ••/• '>! i'H,7 :f,•'•!•*.:.:>?''; •:' V. VtiJi,:'
Congress on solid waste disposal noted that trucking leachate to POTWs was the most
common leachate management method (EPA, 1988d).
Historically, many MSWLFs have not had leachate collection and run-on/runoff
controls. A survey conducted by E?A in 1986 and 1987 identified approximately.6,000
MSWLFs nationwide (EPA, 1988d). Sixty-one percent of these landfills, or 4,016 facilities,
had-run-on/runoff controls. Approximately 11 percent (746 landfills) had leachate collection
systems, and roughly 3.5 percent (228 landfills) recirculated leachate. Since only 746 existing
landfills out of 6,000 currently have leachate collection systems, it is possible that more than
5,200 will be required to install such systems, assuming the proposed rule is finalized without
changes. (It is more likely, however, that only 3,000 to 4,000 will continue to operate and.
expand and, thus, be required to install leachate collection). Roughly 2,000 will be required to
install run-on/runoff controls.
"',,'' ., , • • ' " ,!iiy).,::, .,„'.• '.,',. , ' ',!,; , , "•!" i, i. i
It is difficult to estimate the volume of leachate that will be generated by 'these landfills.
1 ' „ "' " ," | ' ' ' ,' " ;", ' '''"' ' ,1'1'. ' ''""""''''"', •' ' ' • ' • '
Leachate generation depends on many site-specific variables, including the amount of annual
3-80-
-------
precipitation, surface water conditions, underlying soil conditions, waste characteristics, and
the landfill design specifications. It is reasonable to assume, however, that generated
leachate will be considered for disposal at POTWs, particularity since 86 percent of MSWLFs
are owned by government entities, often the same public entity that operates the POTW
(EPA, 1988d).
Leachate composition also varies among landfills because of such variables as waste
characteristics and landfill age. EPA has compiled a data base of leachate data from 70
MSWLFs (EPA, 1988d). Leachate from 53 of the landfills was analyzed for organic
pollutants, and leachate from 62 landfills was analyzed for inorganic pollutants. The following
table identifies the most commonly detected organic pollutants. .
Organic Constituent
1,1-Dichloroethane .
Trans-1,2-Dichloroethylene
Ethylbenzene
Methylene Chloride
Phenol
Toluene
Concentration Range
(parts per million)
0.004 - 44
0.002 - 4.8
0.006-4.9
0.002 - 220
0.007 - 28.8
0.006 - 18
The next table lists the most commonly detected inorganic pollutants.
Pollutants
Arsenic
Barium
Cadmium
Chloride
Chromium (total)
Copper
Iron
Lead
Manganese
Nickel
Nitrate
Sodium
Sulfate
Concentration Range
(parts per million)
0.0002 - 0.982
0.11-5
0.007 - 0.15
31-5,475
0.0005-1.9
0.003-2.8
0.22-2,280
0.005 - 1.6
0.03-79
0.02-2.2
0.01 - 51
12-2,574
8-1,400
Source: EPA (1988d).
3-81
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Data on MSWLF leachate were not compiled forlsuch factors as sampling and handling
procedures, analytical methods, pollutants for which samples were analyzed, and landfill
conditions. The data do, however, highlight the wide variability in both the pollutants
identified and their concentrations. It should be kept in mind that MSWLFs may accept
hazardous waste from household or small quantity generators, nonhazardous industrial
process waste, demolition waste, and municipal incinerator ash. In the past, MSWLFs also
accepted pre-RCRA regulated hazardous waste. These wastestreams indicate the potential
for leachate to contain a wide variety of organic and inorganic toxic pollutants.
In addition to the requirements for leachate collection and run-on/runoff controls, the
revised criteria (if finalized as proposed) will require MSWLFs to miex^^aniecffin action
for releases to ground water. The most common form of treatment for contaminated ground
water is removal and treatment (EPA, 1988d). As with estimating the volume of leachate
generated, it is difficult to estimate the volume of contaminated ground water potentially
requiring treatment. The volume of contaminated ground wafer depends upon the age of the
landfill, the flow rate of ground water in the vicinity of the landfill, and the dispersion
characteristics of the contaminants.
The number of MSWLFs requiring corrective action could be significant. For example,
of the 1,189 sites on EPA's February 1991 revision of the NPL, approximately 20 percent
were municipal landfills. An additional 116 landfills not on Se NPL have been identified as
requiring cleanup under State hazardous waste programs in eight States (GAO, 1989). The
Regulatory Impact Analysis for the proposed municipal solid waste landfill rule estimated
that the percentage of landfills requiring corrective action could range from 5 to 40 percent
(300-2,400 landfills), depending on the location of the point of compliance (EPA, l988d).23
\ - h _ | • •
3.4.4.5 Used Oil Recycling
An estimated 1,350 million gallons of used oil are generated each year from utilities,
metal working plants, railroad yards, service stations, and other transportation-related
facilities. Of this volume, EPA estimates that over 193 million gallons of used oil are
II I HI II J
23. The point of compliance can be considered a boundary; ground water beyond this point
must meet cleanup standards.
3-82
generated annually by people in .the United Spates who change their oil in their automobiles
and that an estimated 2 percent of do-it-yourselfers empty 4 million gallons of oil into
.sanitary sewers. Another 132 million gallons are dumped by "other automotive generators,"
but the proportion of that discharged to sewers is unknown (Voorhees, 1989).
EPA and various States are now undertaking serious efforts to recycle used oil. A
reduction in improperly disposed oil (i.e., dumped to sanitary sewers) would be expected.
However, discharges to sanitary sewers from centralized used oil recyclers will still need to
be controlled by POTWs.24
The recycling of waste oils normally requires pretreatment (through heating, screening,
gravity separation, filtering, chemical flocculation, and dehydration) to remove bottoms,
sediments, and water prior to re-refining. The resulting wastewaters contain organics and
toxic metals (e.g., lead, chromium, arsenic). The discharge of such wastewaters to POTWs
can cause problems at the wastewater treatment plant.
For example, the city of St. Petersburg, Florida, experienced over 30 major interferences
in a 6-month period in 1988 from an "unknown substance." After an investigation was
' , r . -. . i • ... •
initiated, involving extensive sewer line testing, the source was identified as a used oil
recycler. Samples taken from the sewer line in the vicinity of the oil recycler were described
as containing a "complex hydrocarbon mixture" with hydrocarbons n-rionane through n-
dodecane, toluene, and other benzene compounds. POTW personnel identified that, in
addition to the effect of the discharge on the plant's dissolved oxygen levels in the aerators
arid the deleterious impact on the biological treatment process, the discharge also affected the
health of, plant employees and resulted in NPDES permit violations. An administrative order.
was issued, and the used oil recycler installed an air stripper to remove volatile pollutants
from recycling wastewaters prior to discharge (telephone conversation between R. Linett and
J.Parnell, 1990). -
3.5 CASE STUDIES
The three case studies for this report examined the number and types of industries
regulated by three local pretreatment programs. Table 3-25 summarizes the industrial
24. As discussed in Subsection 3.2.2.4, EPA is currently examining'the used oil reclamation
and re-refining industry for possible regulation under national categorical standards.
Management standards for recycled used oil under RCRA are also being examined, as is
the listing of used oil as a hazardous waste.
3-83
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3-84
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contributors to each of the programs. The.case studies also investigated the relative
contributions of flow from domestic and industrial sources. As can be seen in Table 3-26, all
three programs received between 18 and 25 percent of the total flow from significant industrial
users.
All three POTWs have noted reductions in loadings of pollutants from industrial users.
However, pollutants discharged from domestic and commercial sources have stayed constant
and in some cases have increased. Figure 3-2 summarizes the sources of several pollutants
discharged to the Thomasville POTW. As shown, domestic and commercial loadings
constitute less than 50 percent of the total POTW loading for all pollutants except silver, for
which domestic and commercial loadings account for more than 90 percent of the total POTW.
loading. Hampton Roads Sanitation District (HRSD) has experienced substantial decreases
in metals loading since it began implementing its pretreatment program; however, loadings of
copper and zinc have remained constant, a result the POTW attributes to domestic sources.
Pocatello, like HRSD; routinely detects only copper and zinc in its effluent. Pocatello sampled
its industrial sources and domestic areas and determined that domestic sources are the
primary contributors of copper and zinc. Pocatello also has sampled raw water sources and
has further identified the source of copper and zinc to probably be corrosion of piping and
related appurtenances. .
3.6 POLLUTION PREVENTION INITIATIVES
In October 1988, Congress passed the Pollution Prevention Act of 1990, which states as
national policy that pollution should be prevented or reduced at its source wherever possible.
The Act requires direct EPA involvement in the advocacy, measurement;.and regulation of
source reduction techniques, and it provides a State grant program to encourage, source
reduction by businesses. To date, EPA has published pollution prevention guidance manuals
for seven industrial categories; manuals for another 11 categories are scheduled for
publication in 1991.
Some industrial facilities haive implemented pollution prevention technologies as a cost-
efficient means of managing their wastestreams. For example, it may be more
environmentally productive and less costly to reformulate products, modify processes,
redesign equipment, or reuse waste materials than to implement traditional end-of-pipe
controls. The implementation of pollution prevention measures at industrial facilities has
been shown to reduce the amounts of pollutants in air, water, sludge, solid waste, and
wastewater. As more .industries recognize the environmental and economic benefits of
3-85
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Figure 3-2. Sources of Toxic Pollutants Discharged
to the Thomasville, North Carolina, POTW
3-87 .
-------
pollution prevention technologies over pollution control technologies, it is likely that more
industries will be discharging fewer toxic pollutants into POTWs. the pretreatment program
is well suited to the use of pollution prevention as a means of protecting POTWs and their
sludge.
Through the EPA Pollution Prevention Information Clearinghouse (PPIC), EPA collects,
studies, develops, arid distributes information concerning pollution prevention. Table 3-27
summarizes the types of pollution prevention techniques for various industrial categories
presented in the PPIG. The general techniques include:
• Source Reduction—Reduces the volume (and toxicity) of waste generated or
transferred to the environment. Reduction, techniques include waste segregation,
materials handling and housekeeping, process modifications, equipment replacement,
employee training, and development of corporate strategies.
• Waste Recycle/Recovery—Reduces the amount of waste that must ultimately be
disposed of, such as:
- Closed-Loop Recycling: Alteration of production line to include reuse of materials
as part of the manufacturing process. •
- Reuse of Original Product: Reuse of waste materials in their original form. For
example, bottles that are sterilized and reused require less energy and virgin
material. . ; •
- Primary Recycling: Where material reuse is not possible, the materials in the
waste are reclaimed for future use in a similar product. For example, waste
bottles are converted to glass.
• - Secondary Recycling: When reuse and primary recycling are hot possible, waste
materials are converted directly into a new product. For example, paper is made
into compost.
<• Energy Recovery—Recovers energy or heat from wastes through combustion,
incineration, or thermal transfer.
Table 3-27 shows that pollution prevention case studies exist for 36 of the 47 industrial
categories examined for this report. Therefore, it has been shown that reductions in toxic
pollutants can be achieved through pollution prevention techniques! Many of these pollutants
have been identified as being discharged to POTWs in large quantities. One of the more
prevalent pollution prevention techniques used is the recycling of solvents, many of which
were identified in Section 3.2 of this report as being discharged by most industries.
. '" , • ';' • '„, i • I h ,.',,'.,
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Several POTWs have begun to integrate the concept of pollution prevention into their
local pretreatment programs as a means of controlling toxic discharges. For example, the
Massachusetts Water Resources Authority (MWRA) Sewerage Division (Boston) has
.. • "••• - 3-88- ." '. ' ' ' :
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initiated an industrial source reduction demonstration/pilot project to examine pollution
prevention as a means of controlling toxic pollutants. In December 1990, the MWRA
\i " .
announced a new permit fee system intended to create economic incentives for reducing
industry's use of toxics, under which industrial dischargers of toxics would be assessed.
higher annual fees than industrial dischargers of nontoxic wastewaters.
In another example, the Milwaukee Metropolitan Sewerage District (MMSD), in
response to new NPDES limits for toxics and the upcoming sewage sludge regulations, has
initiated an area-wide toxic waste minimization initiative. The initiative includes a task force
made up of local interests working with MMSD to develop a comprehensive pollution
prevention program.
As shown in Table 3-18, over 600 household hazardous waste programs were in place
in 1989. Many of these are operated in conjunction with POTW pretreatment programs.
POTWs discharging into marine waters may be required to implement pollution
prevention initiatives under Section 403(c) of the Clean Water Act. Ocean Discharge Criteria
regulations (45 FR 65457) contain provisions for determining "No Irreparable Harm" that
require that reasonable alternatives to disposal (including process modifications) be
explored. Section 403(c) may provide a valuable tool in furthering pollution prevention
practices at POTWs discharging to marine waters.
3.7 FINDINGS
As described throughout this chapter, a variety of toxic pollutants are discharged or
have .the potential to be discharged to POTWs from a variety of sources. .Although no one
data base contains data describing all of these sources, several data bases at least indicate
the numbers and types of toxic pollutants being discharged to POTWs,
3.7.1 Industrial and Commercial Sources
This subsection presents the findings regarding industrial and commercial sources of
toxic pollutants being discharged to POTWs:
• Local POTW and State pretreatment programs currently regulate an estimated
30,000 SIUs, 40 percent of which are subject to national categorical standards. Local
pretreatment programs regulate an average of about 10 SIUs each. In addition,
.approximately 800 SIUs are regulated by approval authorities (approved States or
3-93-
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EPA Regions), although current estimates are considered low because data for many
States were not available at the national level.
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• Nationally, the estimated flow from industrial sources accounts for just over 15
percent of total POTW flow (approximately 2'l billion gallons per day) for POTWs
with local pretreatment programs. .
• Assuming that no pretreatment standards were in place, the DSS reported that
between 204 million and 218 million pounds per year of hazardous metal pollutants
and between 82 million and 254 million pounds per year of hazardous organic
pollutants would be discharged to POTWs at raw (untreated) discharge levels.
' Assuming full compliance with categorical Pretreatment Standards for Existing
Sources (PSES), EPA estimated that hazardous metal pollutants discharged to
POTWs from categorical industries would be reduced to less than 14 million pounds
per year, and hazardous organic pollutants discharged to POTWs would be reduced
to less than 51 million pounds per year. After implementation of PSES and assuming
full compliance, loadings of toxic metals to POTWs are highest for the following five
DSS industrial categories: electroplating and metal finishing; industrial, and
commercial laundries; organic chemicals manufacturing; coal, oil, petroleum products
and refining; and pulp and paper. Likewise, after-PSES loadings of toxic organics are
highest for the following five DSS 'industrial categories: equipment manufacture and
assembly; pharmaceutical manufacture; organic .chemicals manufacturing; coal, oil,
petroleum products and refining; and industrial and commercial laundries.
• TRIS reported that more than 680 million pounds of toxic pollutants were discharged
by over 5,700 facilities to more than 1,700 POTWs in 1988. The industrial categories
reporting the largest discharges to POTWs were fertilizer manufacturing (143 million
pounds), organic chemicals manufacturing (93 million pounds), dye manufacturing and
formulation (68 million pounds), pulp and paper mills (47 million pounds), and food.
and food byproducts processing (38 million pounds).
• TRIS reported discharges of more than 200 toxic pollutants to POTWs: ammonium
sulfate discharged in the highest amount and sulfuric acid by the most facilities.
Seventeen of the top 40 toxic pollutants being released to POTWs (with respect to
quantity and number of facilities releasing) were priority pollutants, the most common
of which were copper, zinc, chromium, nickel, toluene, lead, 1,1,1-trichloroethane, and
dichloromethane. The most common nonpriority toxic pollutants reported, were
sulfuric acid, ammonium sulfate, methanol, hydrochloric acid, and phsophoric acid.
• For the 167 pollutants analyzed in the DSS (including copper and zinc, which were
'not part of the original DSS estimates), the loadings of toxic pollutants to POTWs
reported in TRIS (159 million pounds) exceed those ih the DSS (60 million pounds),
even though the DSS captured more facilities discharging to POTWs. This is likely
due to differences in the methods used to calculate and report loadings — TRIS is
based on releases reported by individual facilities for 1988; DSS loadings represent
EPA estimates based on representative pre-1986 industrial category data.
• Generally, TRIS supported many findings of the DSS, the most significant of which is
that higher quantities of nonpriority pollutants than priority pollutants are being
discharged to POTWs.
• EPA's 304(m) studies of 10 industrial categories show that several commercial and
industrial categories discharge significant quantities of toxic pollutants to POTWs.
3-94
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The machinery manufacturing and rebuilding category was estimated to generate the
largest number of toxic pollutants (134, including 73 priority pollutants). For those
industries where estimates were provided, loadings of priority volatile organics
ranged from 37,960 pounds per year for hospitals to just over 2 million pounds per
year for pharmaceutical manufacturing. Loadings of nonpriority volatile organics
ranged from 545,000 pounds per year (hospitals) to 24 million pounds per year
(industrial laundries). These findings support those of the DSS, which also
estimated that significant quantities of nonpriority pollutants are being discharged to
POTWs.
? Local POTW data collected by the State of North Carolina indicate that several
industries not regulated by national categorical standards, such as fertilizer
manufacturing, ink manufacturing, wood furniture manufacturing, and transportation
services, may discharge significant numbers and quantities of toxic pollutants.
*•."',' ' '
3.7.2 Domestic Sources ...,--
Although toxic pollutants discharged to POTWs are most commonly associated with
industrial and commercial discharges, domestic wastewaters can contain toxic pollutants at
concentrations that pose a threat to the environment. The findings regarding domestic
sources of toxic pollutants can be summarized as follows:
• Thirty-five toxic pollutants were identified by 15 municipalities in domestic
wastewater. A variety of metals were present, with relatively high concentrations of
copper, iron, lead, and zinc.' The toxic organic pollutants detected include pesticides,
polynuclear aromatic hydrocarbons, and chlorinated solvents.
• Many household hazardous wastes, which can contain a variety of toxic pollutants,
can be discharged by homeowners to POTWs. Many States and POTWs have begun
to control the disposal of household hazardous wastes by implementing voluntary-
hazardous waste collection programs. In 1989, over 600 collection programs in 35
States were underway.
• Although toxic pollutants found in source waters will be treated as mandated by the
Safe Drinking Water Act to levels that will protect human health, the collective
loadings of these pollutants in drinking water may be significant for the POTWs that
ultimately receive this water. .
• Evaluation of 25 local limits submissions in EPA Region VI indicated that domestic,
contributions for several toxic pollutants account for a significant portion of the
allowable headworks loadings calculated for these pollutants. This was particularly
true for zinc, which accounted for more than 50 percent of the allowable headworks
loadings for 14 of the 25 local limits submissions reviewed.
3-95
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3.7.3 Other Sources
Other sources of wastewater to POTWs can also be significant contributors of toxic
pollutants: . . • "
• The EPA Nationwide Urban Runoff Program found 76prioritypollutants detected in
storm water discharges. Preliminary estimates show that fewer than 20 percent of
prctreatment POTWs have combined sewer overflows.
• Inflow/infiltration of contaminated ground water has been shown in isolated instances
to be the source of toxic pollutant discharges to POTWs. National estimates of the
types and quantities of toxic pollutants entering POTWs through inflow/infiltration
are not available.
• Although limited data exist, discharges from waste haulers have been found to be a •
source of toxic pollutants to POTWs. The types and quantities of toxic pollutants are
highly variable, as the toxics present generally depend upon the origin of the wastes
hauled. Data collected by EPA concerning septage hauler discharges show that
significant concentrations of both priority and nonpriority pollutants are present,
including iron, zinc, manganese,' barium, copper, methyl alcohol, isopropyl alcohol, and
acetone. '
. • The implementation of the RCRA and CERCLA programs may result in appreciable
increases in the types and quantities of toxic pollutants discharged to POTWs. There
are several cases in which RCRA corrective actions and CERCLA remedial actions
have involved POTWs for the ultimate disposal of treated liquid wastes. EPA
estimates that 1,700 RCRA facilities and 440 Superfund sites will require remediation
of ground water that can contain a. variety of toxic pollutants.
• POTWs are also an option for wastewaters resulting from cleanups of ground water
and soil as required under the UST program. EPA estimates that almost 340,000'
USTs are leaking and will require remediation.
• Soon to be promulgated requirements for municipal solid waste landfills will probably •
result in increased volumes of wastewaters as a result of run-on/runoff controls,,
leachate collection, and ground-water remediation. One alternative method for
leachate management is hauling to POTWs; the types of toxic pollutants present in
leachates vary according to the wastes accepted by the landfill. More than 5,000
MSWLFs will be installing leachate collection systems that may be discharging to
, POTWS. ' ,. ' ''' ,, ' ;•''';'',';;'; i j™ ''_' y..'; 7 ".','•.', ,"• '•'.,
3.7.4 Pollution Prevention
POTWs and their industrial users have demonstrated an understanding of pollution
prevention and the opportunities it affords to reduce loadings of toxic pollutants. Reductions
in toxic pollutant discharges to POTWs can be achieved through the pollution prevention
techniques involving source reduction, waste recycle/recovery, and energy recovery. EPA
has found that pollution prevention techniques have been used at 36 of the 47 industrial
categories evaluated in this report. . •
3-96
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REFERENCES
Association of Metropolitan Sewerage Agencies. 1990. 1988-89 AMSA Pretreatment
Survey, Final Report. .
City of Blackwell, Oklahoma. 1990. Final Toxicity Reduction Evaluation Progress for July
1989 through March 1990. .
City of Largo, Florida. 1989. Toxicity Control Plan, Report of Toxicity Source Evaluation.
Hammer, MJ. 1975. Water and Wastewater Technology. New York: John Wiley and Sons,
Inc.
'f' • •' • . -
Hazen and Sawyer. 1990. Feasibility of Diazinon Treatment for the City of Hollywood
Southern Regional Wastewater Treatment Plant Effluent.
Maddaus, William O. 1987. Water Conservation. Washington, DC: American Water Works
Association. . - . . - .
New England Water Pollution Control Association. 1989. Position Paper on U.S. EPA Final
National CSO Control Strategy. CSO Technical Committee. ' ^
New Jersey Department of Environmental Protection. 1990. White Paper on Beneficial Use
of Sewage Sludge.
Pontius, Frederick W. 1990. Complying With the~New Drinking Water Quality Regulations.
JournalAWWA. ..
Spencer, R. 1990. "Boston Moves to End Harbor Dumping." Biocycle.
Telephone conversation between R. Linett (SAIC) and Dr. John Parnell (Industrial
Pretreatment Coordinator for the -City of St. Petersburg). July 17, 1990.
U.S. Environmental Protection Agency. 1991. Supplemental Manual on the Development and
Implementation of Local Discharge Limitations Under the Pretreatment Program:
Domestic/Commercial Loadings Removal Efficiency Estimation. Washington, DC:
Office of Water Enforcement and Permits. .
U.S. EPA. 1990a. Local Limits Submissions for Local Pretreatment Programs. Region VI.
U.S. EPA. 1990b. Proceedings of the 4th National Conference on Household Hazardous
Waste Management, 6-8 November, 1989, at Orlando, Florida.
U.S. EPA. 1990c. Results from State CSO Strategies submitted to EPA. Washington, DC:
Office of Water Enforcement and Permits.. .
U.S. EPA. 1989a. Model NPDES Permit for Discharges Resulting from the Cleanup of
Gasoline Released from Underground Storage Tanks. Washington, DC: Office of Water
Enforcement and Permits and Office of Underground Storage Tanks.
U.S. EPA. 1989b. Preliminary Data Summary for the Drum Reconditioning Industry.
Washington, DC: Office of Water Regulations and Standards. EPA/440/1-89/101.
U.S. EPA. 1989c. Preliminary Data Summary for the Hazardous Waste Treatment Industry.
Washington, DC: Office of Water Regulations and Standards. EPA/440/1-89/100.
U.S. EPA. 1989d. Preliminary Data Summary for the Hospitals Point Source Category.
Washington, DC: Office of Water, Regulations and Standards. Government Printing
Office: EPA/440/l-89/060-n.
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U.S. EPA. 1989e Preliminary Data Summary for Industrial Laundries. Washington, DC:
* Office of Water Regulations and Standards. EPA/440/1-89.
U S EPA 1989f Preliminary Data Summary for the Machinery Manufacturing and
•'"' Rebuilding Industry. Washington, DC: Office of Water Regulations and Standards.
EPA/440/1-89/106.
U.S. EPA. 1989g. Preliminary Data Summary for the Paint Formulating Point Source
Category. Washington, DC: Office of Water Regulations and Standards. EPA/440/1-
89/050.
US EPA 1989h. Preliminary Data Summary for the Pharmaceutical Manufacturing Point
Source Category. Washington, DC: Office of Water Regulations and Standards.
EPA/440/1-89/084. i . ^ • ^;. ; i ' ' \ ^^ t ^^ ^( ; rni a['\ '; ^
US EPA 1989i 'Preliminary Data Summary for the Solvent Recycling Industry.
" "Washington, DC: Office of Water Regulations and Standards. EPA/440/1-89/102.
U.S. EPA. '1989J. Preliminary Data Summary for the Transportation ^uVment Cleaning
Industry. Washington, DC: Office of Water Regulations and Standards. EPA/440/1-
89/104.
U S EPA 1989k. Preliminary Data Summary for the Used Oil Reclamation and Re-Refining
Industry. Washington, DC: Office of Water Regulations and Standards. EPA/1-
' 89/oi4. ; . • _._• _ ; ,. ; ' ; _ j. '
US EPA 1988a Ground-Water Monitoring andCorrective ActionI (Subpart E)-Criteria for
' ' Municipal Solid Waste Landfalls (40CFR Part 258)-Subtitle D of RCRA (Background
Document). Washington, DC: Office of Solid Waste.
U S EPA 1988b. Regulatory Impact Analysis in Support of the Proposed Revisions to the
National Oil and Hazardous Substances Poll. Contingency Plan. Washington, DC:
Office of Solid Waste " """
U S EPA. 1988c; Regulatory Impact Analysis of Technical Standards for Underground
'Storage Tanks. Washington, DC: Office of Underground Storage Tanks.
US EPA 1988d Summary of Data on Municipal Solid Waste Lanfill Leachate
' ' Characteristics-Criteria for Municipal Solid Waste Landfills (40 CFR Part 258)-Subtitle
D of Resource Conservation and Recover Act (Background Document). Washington,
DC: Office of Solid Waste
U.S. EPA. 1987a. Records of Decision Annual Report^Y 1986^^
Solid Waste.
U.S. EPA. 1987b. Resource Conservation and Recovery Act Subtitle D, Report to Congress,
*' Final Draft. Washington, DC: Office of Solid Waste.
U.S. EPA. 1987c. Underground Storage Tank Corrective Action Technologies. Washington,
DC: Office of Research and Development.
U.S. EPA. 1986a. Quality Criteria for Water 1986. Washington, DC: Office of Water
Regulations and Standards.
US EPA 1986b Report to Congress on the Discharge of Hazardous Wastes to Publicly
' ' Owned Treatment Works. Washington, DC: Office of Water Regulations and
Standards. 530-SW-86-004. .
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U.S. EPA. 1985. National Biennial Report of, Hazardous Waste Generation, and Treatment,
Storage, and Disposal Facilities Regulated Under RCRA, Vol. 2, Meth. and Data.
U.S. EPA. 1983. Results of the Nationwide Urban Runoff Program. Washington, DC: U.S.
General Accounting Office. PB84-1.85552.
U.S. EPA. 1981. Assessment of the Impacts of Industrial Discharges on Publicly Owned
Treatment Works. Prepared by JRB Associates for EPA. Washington, DC: Office of
Water Regulations and Standards.
U.S. General Accounting Office. 1989. State Management of Municipal Landfills and Landfill
Expansions. Washington, DC.
Voorhees, Phillip H., November 1989. "Generation and Flow of Used Oil in the United
States in 1988." Mimeographed. Washington, DC: Temple, Barker & Sloane, Inc.
EPA Contract No. 68-01-7290.
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4. REMOVAL OF Toxic POLLUTANTS BY SECONDARY TREATMENT
Section 519(a)(2) of the Water Quality Act of 1987 required the U.S. Environmental
Protection Agency (EPA) to study "the extent to which secondary treatment at .publicly
owned treatment works (POTWs) removes toxic pollutants." The purpose of wastewater
treatment is to remove pollutants that may have a deleterious effect on human health or
aquatic organisms. Municipal wastewater treatment plants are principally designed to
remove conventional pollutants: biochemical oxygen demand, (BOD), total suspended solids
(TSS), oil and grease, pH, and fecal coliform. The design of wastewater treatment plants is
based on plant flow, raw wastewater loadings of BOD and TSS, and the target efficiencies
with which these pollutants are to be removed by physical treatment units and biological
processes. Removal of metals and toxic organic pollutants generally is not considered in the
design of municipal wastewater treatment plants.
The removal of most toxic pollutants'from wastewaters by municipal treatment plants
(i.e., POTWs) is incidental to the treatment of conventional pollutants and should be
considered in terms of partitioning among alternative pathways. Some toxic organic
pollutants biodegrade to varying extents. Those that are not^biodegraded either sorb to
particulates and are removed with sewage sludges, volatilize at, various stages in treatment
trains, or pass through the POTWs and are discharged to the receiving waters. Metals and
some organic pollutants are conservative pollutants; they are not biodegraded in POTWs.
Metals and other conservative pollutants either enter wastewater sludges by settling or
sorption to solids, or they pass through POTWs and are discharged in effluent of POTWs.
An understanding of the ability .of municipal treatment plants to remove toxic pollutants
from wastewaters is central to the administration of pretreatment controls at the Federal,
State, and local levels, particularly with respect to the development of categorical standards,
the administration of removal credits, and the calculation of local discharge limitations (local
limits).
, Categorical Standards — Before promulgating a categorical standard for a pollutant, EPA
must make a threshold determination that the pollutant may pass through POTWs or
interfere with their treatment processes. EPA addresses the potential for pass through by
comparing the average removal capability of-POTWs with the average removal rate achieved
.by industries that use the best available technology economically achievable (BAT) for their
designated industrial categories and that discharge wastes directly to receiving waters rather
4-1
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than to POTWs. If the average POTW removal rate for a particular pollutant is equal to or
better than the average'BAT removal rate, a judgment is made that treatment at the POTW
is sufficient to address pass through, and no categorical standard is promulgated for that
pollutant. If the average POTW removal rate is lower than the average BAT rate, however, a
standard is promulgated at a level that reflects use of BAT.
; , • • „' • ": ,'•'.,•.•..,'•- i i i I i i
It is clear that EPA's ability to set categorical standards is predicated on a sound
understanding of the ability of POTWs to remove pollutants.
Removal Credits - Congress recognized that treatment of wastewater by an indirect
discharger (i.e., by an industry that discharges its wastewater to a POTW rather than
directly to receiving waters) to meet categorical discharge standards and the subsequent
treatment by the receiving POTW creates the potential for dupiicative treatment (i.e., the
industry may install processes to remove pollutants that would otherwise be removed by the
municipal wastewater treatment plant). Section 307(b) of the Clean Water Act (CWA)
reflects this concern and provides for adjustment of categorical standards through removal
credits. EPA's removal credit regulations are at 40 CFR 403.7. Effective implementation of
removal credits requires both a clear definition of what constitutes removal and a means for
demonstrating consistency of POTW performance in achieving such removals. (See Chapter
5 for a detailed description Of the removal credits program.)
Local Limits - In accordance with 40 CFR 403.5, POTWs required to develop local
pretreatment programs must periodically evaluate the need for local discharge limitations.,
(POTWs without pretreatment programs must also develop local limits in certain cases.)
EPA's Guidance Manual on the Development and Implementation of Local Discharge
Limitations Under the Pretreatment Program (EPA, 1987) provides step-by-step instruction
on the local limits development process: Chapter 5 describes tfie local limits development
process in detail.
An understanding of removals is critical to developing effective local limits. If POTWs
overestimate treatment plant removal efficiencies, the potential exists for the plant to
experience inhibition or upset of its biological processes and/or to violate the conditions of its
National Pollutant Discharge Elimination System (NPDES) permit. Where removal
efficiencies are underestimated, the POTW may establish overly stringent standards.
4-2 -
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Finally, an understanding of the pollutant removals achieved at POTWs is important in
the evaluation of alternative remediation technologies for use at Superfund sites. In many
cases, the discharge of ground water to POTWs has been selected based on an assumption
that the POTW would be capable of providing a consistent level of treatment and protection of
receiving waters. Should this assumption be invalid, the Agency may wish to reconsider
current policy that views the discharge of wastewater to POTWs as an acceptable option.
Section 4.1 briefly discusses the types of treatment units and process operations that
make up a wastewater treatment plant Sections 4.2 and 4.3 present and analyze data from
the DSS and other data bases relating to pollutant removals at secondary wastewater
treatment plants. •
4.1 SECONDARY WASTEWATER TREATMENT PLANTS
The purpose of wastewater treatment is to remove pollutants that may have a
deleterious effect on'human health or aquatic organisms. Traditionally, municipal wastewater
treatment plants have been designed for the treatment of conventional pollutants: BOD, TSS,
oil and grease, pH, and fecal coliform. ,
The methods used to treat municipal wastewaters usually combine physical treatment
units (e.g., screening,.degritting, comminution, and sedimentation) and biological treatment
processes (e.g., activated sludge). Figure 4-1 provides a simplified flow diagram of a
secondary treatment plant. The treatment process, comprising five stages (preliminary
treatment, primary treatment, secondary treatment, disinfection, sludge conditioning), is
described in the following paragraphs. . . .
Preliminary treatment may include a variety of treatment units, such as screening, grit
removal, and comminution. The main purpose of these units, identified below, is to remove
large debris, sand, gravel,, and nonputrescible organic matter, thereby protecting downstream
pumps, valves, and piping from wear, abrasion, and clogging.
• Screening generally involves the use of parallel bars or gratings with uniform spacing,
designed to remove larger debris and solids from the wastewater. Some treatment
plants use mechanical cleaning racks for this function.
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• Grit chambers are designed to remove inert solids from the wastewater, based on
differential settling rates of the wastewater solids and the flow and velocity of the
wastewater. Some grit chambers are aerated, which provides better control of the
size of particles to be removed. ' ,
• Gomminutors cut large wastewater solids into a uniform size of less than one-quarter
inch. .
The residuals generated from preliminary treatment are largely inert and are generally
disposed of in landfills. .
Primary treatment is the removal of settlable solids from the wastewater through
sedimentation in clarifiers (settling tanks). In addition, floatable materials (e.g., oil and
grease) are removed by skimming the surface of the clarifier. At some wastewater. treatment
plants, wastewater from sludge digesters (described below) is returned to the primary
clarifiers.
Residuals generated from primary treatment consist of the sludges that settle out and
the skimmings from the surface of the clarifier. Primary solids may be mixed with secondary
sludges (wasted from the secondary clarifiers) prior to subsequent conditioning and disposal.
Sludge conditioning and disposal are detailed below.
Secondary treatment processes are designed to break down pollutants from wastewater
through biological processes. These processes include a wide array of technologies but most
involve variations of activated sludge processes, attached growth, systems (e.g., trickling
filters and rotating biological contactors), and ponds and other natural systems (e.g.,
stabilization ponds, land treatment). Examples of the more common processes are discussed
below. .
• Activated sludge processes consist of aeration tanks followed by secondary clarifiers.
The aeration tanks contain a microbial population that degrades organic pollutants
through catabolic processes. The tanks are aerated to ensure proper mixing and to
maintain dissolved oxygen levels necessary to support microbial activity. Secondary
clarifiers settle out the biomass and allow for either recycling,of solids to the aeration
tank or conditioning and 'disposal as sludge.
• The recycling of solids to the aeration tanks may allow organics that have sorbed to
the sludge to be retained within the treatment system for periods in excess of the
hydraulic detention time. Thus, volatilization may occur long after the contaminant is
reduced in the treated effluent. •
4-5
-------
•• .','.•'•, " ;• •. " i .'.:;ii. I'lt.'iiK.i1 .: i»(rtf»i.1i.'«j.'lii .- v ''" "'" '"V. £•'" «_ '"
Trickling filters are beds of coarse materials (natural or synthetic) over which the
effluent from primary processes is distributed uniformly. Microorganisms that
biodegrade organics in the wastewater form a slimy covering on the filter media.
Wastewater may be recycled through the filter to allow for a consistent flow across
the filter media. Air forced upward through the filter media enhances oxygen transfer.
Lagoons or stabilization ponds generally are simple basins surrounded by earthen
dikes that provide for the biological stabilization of organic pollutants. Depending on
their depth and specific design, lagoons may be aerobic, anaerobic, facultative, or
aerated systems.
pisinfecrion. most commonly through chlorination, destroys bacteria, pathogens, and
viruses in the wastewater. Excessive free chlorine in the wastewater discharge can,
however, cause aquatic 'toxicity in the receiving stream.
conditioning may include thickening, aerobic or anaerobic digestion, and
dewatering. Sludge digestion processes reduce sludge volume and stabilize solids through
biodegradation of organic matter. Dewatering and drying operations further reduce sludge
volume. Sidestreams generated from sludge conditioning operations are generally returned to
the treatment plant, upstream of secondary treatment units.
Congress directed EPA to evaluate pollutant removals achieved by secondary treatment
plants. This involves assessment of the quantities of pollutants that are removed from the.
wastewater, as well as the fates of those pollutants.
The percent removal of a pollutant in a POTW is the percent reduction of the POTW
influent concentration achieved by POTW treatment processes. The percent removal of a
pollutant in a POTW is defined as:
R = [(Qn - CoutVCinl X 100%
where: R = Removal efficiency (presented as a percent)
Cout = Effluent concentration
= Influent concentration.
Thus, if POTW influent concentration is 50 micrograms per liter (^ig/1) and effluent
concentration is 20 ng/1, the percent removal is [(50-20)/50] X 100 or 60 percent.
4-6
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4,2 DSS POLLUTANT REMOVALS DATA
To estimate the removability and fate of pollutants, the DSS used the results of
research conducted by EPA's Wastewater Environmental Research Laboratory (WERL) in
Cincinnati, Ohio.
Members of the EPA-WERL group based their estimates of probable fate on then- best
professional judgments (BPJs), summarized literature data, their collective knowledge of
biodegradation literature, their "hands-on" pilot-plant experience with pertinent pollutant
removability, and their experience with ongoing treatability studies. They used Henry's Law
Constants, octanol/water partition coefficients, and qualitative biodegradation data in making
.the estimates.
EPA-WERL generated removal efficiency estimates based on data obtained from three
EPA-WERL research projects and their BPJ. Estimated pollutant removals were projected
for both acclimated and unacclimated treatment plants. The estimates provided for acclimated
treatment plants were based on a conventional activated sludge wastewater treatment
system meeting secondary treatment requirements and having pollutants influent to the
treatment plant at 500 parts per billion. It was also assumed that the pollutant being
evaluated was discharged to the POTW-with a group of typical toxic pollutants at low
background concentrations. Unacclimated removals data were projected using experimental
data from WERL research studies and knowledge of the available literature.
A limited amount of removal data on unacclimated treatment plant operations supported
the development of the estimates both on overall removal and on volatilization fractions. It is
important to note that because EPA-WERL calculated removal based on the difference
between influent and effluent pollutant concentrations, "removal" for purposes of the DSS
included volatilization.
To determine which EPA-WERL estimates approximate actual, full-scale POTW
removal efficiencies, EPA compared the EPA-WERL estimates in the DSS to removals .
obtained from data on 40 POTWs in Fate of Priority Pollutants in Publicly Owned Treatment
Works (EPA, 1982b) (the "40-PQTW Study"). For selected DSS pollutants, Table 4-1
compares the acclimated and unacclimated percent removal estimates made by EPA-WERL
in the DSS with the percent removals derived from the 40-POTW Study data. No clear
correspondence is seen between the EPA-WERL and the 40-POTW removal estimates.
4-7
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(Table 4-1 provides acclimated and unacclimated removals estimates for organic
compounds but only a single set of estimates for metals. This is because removal of metals
•in biological systems does not depend on biological activity (although metals may sorb to the
biomass and be removed with sludge) and is not influenced by the extent to which the
. , ' , ', ' • • '„ ™i ','.:' I. ', ml,!'!' ' ll;lf ' , ":» ,; " , |,| '!n ,/', r,;' ' . ' „ -, |> I!;1,!,!!,
treatment system is acclimated.)
Table 4-2 presents pollutant fates for those DSS pollutants for which individual sludge
partition rates could be calculated. This table provides a rough mass balance; it employs data
from two different sources—EPA-WERL (September 26,1988, memo from D. F. Bishop to T,
P. OTarrell,. "Estimation of Removability and Impact on RCRA Toxics") estimates for
.fractions removed and stripped (volatilized) and EPA's 40-POTW Study for partitioning to
sludge—estimating the fraction biodegraded by difference. Of tie"80 to 90 percent total
removal estimated for chloroform, for example, Table 4-2 indicates that 70 to 90 percent is
volatilized, 2 percent partitions-to sludge, and 8 to 28 percent is believed to be actually
biodegraded. .
4.3 EVALUATION OF POLLUTANT REMOVAL EFFICIENCY DATA
The pollutant removals and loadings estimates in the DSS provided an important
benchmark for evaluating the impacts of pollutants discharged to wastewater treatment
plants. Since completion of the DSS in 1986, new data bases have been created, providing
additional information on pollutant removal efficiencies at wastewater treatment plants.
These data provide an opportunity to revisit the DSS removal estimates and evaluate the
appropriateness of their use in estimating pollutant removals on a national .and a plant:
specific basis.
To be consistent with the congressional mandate to examine removals at secondary
wastewater treatment plants (and since the DSS estimates assumed an activated sludge
plant meeting secondary discharge standards), the data bases were screened carefully to
ensure that they only contained data consistent with a project definition of secondary
treatment (presented in Subsection 4.3.1).
Subsection 4.3.2 discusses the two major data bases evaluated: a 47-POTW data base
created for this study and a data base that resulted from a study by the Ontario Ministry of
the Environment in support of its Municipal Industrial Strategy for Abatement (MISA)
4-8-
-------
Table 4-1. Comparison of Estimated DSS Percent Removals With Those
Obtained Using 40-POTW Study Data
Pollutant
Arsenic
Cadmium •
Chlorobenzene
Chromium
1,2-Dichlorobenzene
Dichlorodifluoromethane
Ethylbenzene
Lead •'.-•••
Mercury
Methylene Chloride
Nitrobenzene
Selenium
Silver
Tetrachloroethylene
Toluene
1 , 1 , 1 -Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Acrolein
Antimony
Benzene
Bis(2-Chloroethyl) Ether
Bis(2-Chloroethoxy) Methane
Bis(2-Ethylhexyl) Phthalate
Bromomethane
Butyl Benzyl Phthalate
Para-Chloro-Meta-Cresol
Percent Removals
DSS
Acclimated
50
27
90
70
90
95
95
. 90
50
95
90
50
90
90
95
95
95
95
95
— •
95
90
10
90
95
95
95
DSS Unacclimated
Median
90
- — ;
87
95
90
—
—
87
25
— - .
' —
85
90
90
87
90
95
—
90
50
10
90
'95
90
50
Low
90
— .
85
95
90
— ' '
• —
85
20
• —
—
80
90
85
85
85
95
—
90
30
10
90
95
90
40
40-POTW
* (93.9)
86.6
* (99.5)
78.9
91.6 . ,
* (80.3)
96.0
88.5
82.0
**
—
• — • .
91.3
80.1
97.6
87.6
92.0
* (97.9)
—
* (71.5)
94.1
- — • •
—
73.5
* (100)
98.7
* (96.7)
4-9
-------
Table 4-1. Comparison of Estimated DSS Percent Removals With Those
Obtained Using 40-POTW Study Data (continued)
Pollutant
Chloroethane
Chloroform
Chloromethane
2-Chloronaphthalene
Cyanide
Di-n-butyl Phthalate
1,3-Dichlorobenzene .
1,4-Dichlorobenzene
1 ,1-Dichloroethane
1,2-Dichloroethane
l,i-Dichloroethylene
1,2-Trans-Dichloroethylene
2,4-Dichlorophenol
1 ,2-Dichloropropane
Diethyl Phthalate
2,4-Dimethylphenol
Dimethyl Phthalate
Di-N-Octyl Phthalate
Hexachloro-l,3-Butadiene
Hexachloroethane
Naphthalene
Nickel
N-Nitrosodimethyl Amine
Pentachlorophenol
Phenol
1,1,2,2-Tetrachloroethane
Tribromomethane
Percent Removals
DSS
Acclimated
95
90
95
95
90
90
90
' 90
90
90
95
90
95
90
90
95
95
90
95
95
95
35
90
95
95
90
65
DSS Unacclimated
Median
90
80
90
80
— .
90
87
87
80
50
90
80
55 .
70
75
85
65
90
90
90
75 '
—
75
25
85
25
35
Low
90
80
90
80
—
90
85
85
80
30
90
80
50
70
70
80
60
90
90
90
70
—
70
20
80
20
30
40-POTW
—
67.6
97.4
, —
**
88.2
* (100)
* (94.9)
* (100)
* (55.4)
* (81.1)
92.8
— -
* (100)
* (99.2)
'- —
* (100).
* (100)
—
—
98.1
47.5
—
60.6
96.7
* (93.8)
* (90.5)
4-10
-------
Table. 4-1. Comparison of Estimated DSS Percent Removals With Those
Obtained Using 40-POTW Study Data (continued)
Pollutant
1 ,2,4-Trichlorobenzene
1 , 1 ,2-Trichloroethane
2,4,6-Trichlorophenol
Vinyl Chloride
Acenaphthylene
Acrylonitrile
Anthracene
2-Chlorophenol
2,4-Dinitrophenol
Aldrin
Chlordane
Endrin .
Toxaphene
Percent Removals
DSS
Acclimated
85
80
95
95
95
— '
95
95
90
90.
90
95
95
DSS Unacclimated
Median
85
25
55
95
90
75
90
65
75
90 .
90
90
90
Low
85
20
50
95
90
70
90
60
70
90
90
90
90
40-POTW
* (96.6)
* (98.6)
—
99.8
—
—
* (83.1)
: —
— •
* (9112)
. .-r—
.
' . .
* Fewer than five of the POTWs had a percent removal for this pollutant. Percent removal
based on fewer than five POTWs is indicated in parentheses..
** Percent removals were deleted, because of analytical difficulties.
Source: Adapted from the Domestic Sewage Study (EPA, 1986).,
4-11
-------
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(Environment Ontario, 1988). Finally, Subsection 4.3.3 presents an analysis of the data
bases, initially examining trends in pollutant removal efficiencies across wastewater
•treatment plants and then briefly discussing the variability of removals within wastewater
treatment plants.
4.31 Derivation of a Project Definition for Secondary Treatment
As mentioned previously, Congress directed EPA to study "the extent to which
secondary treatment at publicly owned treatment works removes toxic pollutants." However,
the term "secondary treatment" is subject to numerous interpretations. Engineering
definitions of secondary treatment have traditionally been based solely on the type of
treatment technology employed. Such definitions generally encompass the settling of solids
and the biological treatment processes that biodegrade organic pollutants in wastewater.
This type of definition has proven adequate for purposes of treatment plant design and
construction. However,, even well-designed plants may vary in performance, depending on
the proficiency of'plant operators, the adequacy of operation arid maintenance, and the
continued validity of the design considerations. EPA thus determined that a strict
engineering definition of secondary treatment would not be adequate for the purposes of this
study, since such a definition would not screen out poorly designed, operated, or maintained
plants. Only pollutant removals data from properly operated POTWs can provide a
consistent baseline for comparison of pollutant removals; otherwise, removals data could be
an artifact of poor design and/or operation.
EPA regulations also provide a definition of secondary treatment, based in part on the
performance capabilities of the treatment processes employed. Part133 of 40 CFR mandates
' 'the minimum level of effluent quality that secondary treatment facilities must, achieve. The
regulations (40 CFR 133.102) state that forBOD 'ai^'TSC^S^yaverage shall not
exceed 30 milligrams/liter (mg/1), the 7-day average shall not exceed 45 mg/1, and the 30-day
average percent removal shall not be less than 85 percent." In addition, the pH must be
between 6 and 9 standard units.
\ t • .• - ,, ,
Concerned that such a regulatory definition might omit the use of existing treatment
plants that are not as effective in reducing BOD and TSS, EPA defined facilities eligible for
consideration as "equivalent to secondary treatment" (49 FR 37006). Equivalent secondary
treatment facilities provide significant biological treatment but are not designed to
consistently meet the numerical standards noted above. According to current regulations
4-14
-------
(40 CFR 133.105), a facility is eligible for equivalent-to-secondary treatment status if it
meets the following conditions:
• The BOD and. TSS effluent concentrations consistently achievable through proper
operation and maintenance of the treatment works exceed the minimum levels for,
v secondary treatment as specified in 40 CFR 133.102(a) and (c).
• A trickling filter or waste stabilization pond is used as the principal process.
r
• The treatment works provide significant biological treatment of municipal
wastewater.
BOD and TSS limits for such POTWs are a 30-day average of 45 mg/1 and a 7-day
average of 65 mg/1; the 30-day average percent removal must not be less than 65 percent.
EPA used a project definition of secondary treatment that draws from both the
technology- and regulatory-based definitions. This definition includes all wastewater
treatment plants that employ one or more biological treatment processes (i.e., activated
sludge, oxidation ditches, trickling filters, rotating biological contactors, or stabilization
ponds/lagoons) that do not provide tertiary treatment and that are in compliance with
secondary discharge standards for BOD and TSS. Rather than using a strict definition of
compliance as the standard for screening plant performance, EPA used significant non-
compliance (SNC). The definition of SNC recognizes that even well-operated plants may on
occasion experience minor exceedances of their permit limits, which may not reflect overall
operational performance. Moreover, the long-standing administrative use of SNC within
EPA provided for an easily understood benchmark. (The definition of SNC for violations of •
effluent limitations for conventional pollutants is any exceedance that is 1.4 times greater
than the permit discharge limit—the multiplier is 1.2 for toxic pollutants—and that occurs for
2 or more months during a 2-qiiaiter review period; or an exceedance of any parameter limit
by any amount that occurs for any 4 or more months during a 2-quatter period). Canadian
plants included in this study had to meet the same biological treatment technology screen and
achieve 85-percent removal of BOD and TSS.
4.3.2 Pollutant Removals Efficiency Data Bases
EPA based its analysis on full-scale POTW data and did not consider data from pilot-
plant or bench-scale research projects. Pilot-plant and bench-scale biological treatment
/ ' - • '
systems are, by definition, maintained under carefully controlled conditions for such factors as
temperature, flow rates, influent loadings of BOD and possibly toxic pollutants, sludge
4-15.
-------
wasting rates, and aeration rates. Consistency of conditions is necessary for process
optimization, whether for design or modeling purposes. In contrast, full-scale POTWs are
subject to many uncontrollable conditions, including daily and seasonal variations in flows,
temperature, and pollutant loadings. There are significant (differences in treatment train
configurations and operational characteristics among POTWs. All these variables influence
the rates of physical and chemical changes (adsorption, volatilization, biodegradation) that
affect pollutant removals across biological treatment systems and determine pollutant fates
within individual POTWs.
This study examines full-scale treatment plant pollutant removals data from a 47-
POTW data base created by EPA, a study prepared for the Ontario Ministry of the
Environment, and EPA's. 40-POTW Study. Each of these data bases contains data collected
during a specific period and analyzed using different editing rules; they differ in design and
methodology. Each data base was analyzed separately as part of this study of treatment
plant pollutant removals, the differences described above precluding compilation into a single
data set.
r ,,,'••'!'' I . I , ' I
The pollutant removals data presented in the three data bases are largely limited to
priority pollutants. EPA is aware that research has been undertaken on pollutant removals
for pollutants beyond .those evaluated here. However, these are generally bench-scale
research projects, often addressing site-specific concerns; for the reasons discussed
previously, EPA chose to include only full-scale treatment plant data in this evaluation.
The 47-POTW Data Base - As part of the present study, EPA compiled a data base
from readily available information on pollutant removals at 47 POTWs located in EPA
Regions H, ffl, V, VI, VH, VIE, and IX, with the greatest number of plants in Region VI. All
47 POTWs met the definition of secondary treatment described in Subsection 4.3.1 and all are
implementing approved pretreatment programs. Of the 47 POTWs, 39 had flows of less than
15 ingd, 5 had flows of between 15 and 45 mgd, arid 3 had flows of greater than 45 mgd. The
data represented in this data base were collected by POTWs as part of their National
Pollutant Discharge Elimination System (NPDES) permit requirements. These requirements
included the use of sample collection and analytical methodologies conforming to 40 CFR Part
136. " ' . " "'^ ' '"'"' ;= ""..T. ' : '"i,, ',' •.".. • '
To facilitate comparison of the 47-POTW data with other data collected for this study,
average removal efficiencies were calculated for each pollutant for each facility. .(Sampling
4-16
-------
regimes generally involved composite sampling of treatment plant influent and effluent for
between 2 and 5 days.) Average removal efficiencies were calculated based on analysis of
average influent and effluent data. Subsection 4.3.3 of this report summarizes POTW
removal efficiency data from the 47-POTW data base and compares them with removal
efficiency data from DSS and the MISA study. Appendix B-l provides the complete data
sets.
The Ontario Ministry of the Environment's Municipal Industrial Strategy for
(MISA1 Data Base - The purpose of the MISA study was to provide POTW influent and
effluent monitoring data to support the development of monitoring regulations. The study
examined monitoring data for 37 Canadian POTWs. (Sampling involved the collection of
composite samples at locations in the plants representative of the plant influent and effluent
streams, including raw and treated sludges. Composite samples were taken Over periods of 2
to 5 consecutive days.) Of the 37 POTWs in the MISA study, 30 met the project definition of
secondary treatment (i.e., they employed biological wastewater treatment processes and
achieved at least 85-percent removals of influent BOD and TSS). The present study used
data from only these 30 POTWs.
Monitoring conducted in the MISA study covered 144 organic contaminants, 13 metals,
selenium, cyanide, and conventional pollutants. The influent and effluent concentrations were
measured for each contaminant detected during the sampling period. This project made use of
all analytical data sets collected during the study in calculating removal efficiencies. In the
MISA study, pollutant concentrations were reported as geometric means over the sampling
period. For purposes of this report, EPA calculated pollutant removals from the geometric
mean influent and effluent data, provided in the MISA report.
Of the 159 toxic pollutants addressed in the MISA study, 95 were detected in either the
influent or effluent wastestreams of the 30 POTWs that met the project definition of
secondary treatment. Of these 95 pollutants, 43 are common to the DSS list of 165
pollutants. Subsection 4.3.3 discusses these data and compares them with DSS and the 47-
POTW data base. Appendix B-2 provides the complete MISA data sets for the 30 POTWs
included in this analysis.
The actual list of pollutants included in the performance comparisons was selected for
each data base based on commonality with the DSS pollutant list and on the number of
treatment plants reporting pollutant removals data. The comparison included only those
' 4-17"
-------
parameters for which at least five data sets (representing five POTWs) were obtained.
Table 4-3 lists the DSS pollutants common to either the 47-POTW data base, the MISA
study, or both used in the comparisons. Copper was added to the analysis even though it is
not a DSS pollutant because of its occurrence in all sewage.
The pollutant removals data available for analysis and discussion in this chapter reflect
only a limited number of pollutants. Historically, there has beenlittle incentive for POTWs to
conduct treatment plant monitoring for pollutants other than ''metals'. This is because cost for
conducting analysis for organic contaminants is far greater ffian-that for metals (it is not
uncommon for POTWs to perform metals analysis inhouse). In addition, for many POTWs,
regulatory requirements (NPDES permits, sludge management requirements) do not
currently include limitations or monitoring requirements for organics.
4.3.3 Analysis of Secondary Treatment Plant Pollutant Removals Data
This subsection summarizes the removal efficiency data from the 47-POTW data base and
the MISA study and compares the Jesuits to DSS removal efficiency estimates. After
obtaining pollutant removals data and creating a list of pollutants for which removals could be
evaluated, EPA conducted a trend analysis to characterize pollutant removals. Pollutant
removal efficiency distributions were examined to determine whether any trends exist in the
frequency of occurrence.
Subsection 4.3.3.1 analyzes pollutant removal efficiencies achieved across a large
number of secondary treatment plants. The analysis includes an evaluation of frequency
distributions of removals obtained from the 47-POTW and MISA data bases. The variability
in pollutant removals among treatment plants is also characterized in terms of the median and
inter-quartile ranges obtained from removal frequency distributions by pollutant. These
ranges are then compared to estimated unacclimated removals in DSS. Subsection 4.3.3.2
delineates an approach for characterizing pollutant removals that could be used where wide
fluctuations in pollutant removals are observed. . ,
In establishing arid interpreting POTW-specific removal efficiencies, it was necessary
to adopt a number of data interpretation conventions. These conventions are described briefly
in the following discussion.
Comparisons of removal efficiencies with DSS estimates were made against
unacclimated. rather than acclimated, DSS values. In establishing acclimated removal
4-18'
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Table 4-3. Pollutants Considered in DSS, the MISA Study, and the
47-POTW Data Base
Pollutants
Antimony
Barium
Cadmium
Chromium
Nickel
Silver
Zinc
Copper
Lead
Cyanide
Mercury
Arsenic
Selenium
Butylbenzyl Phthalate
M-Cresol .
Phenol .
Naphthalene
Chloroform • .
Ethyl Benzene
M & P Xylenes
O Xylenes
1 , 1 , 1 -Trichloroethane
Trichloroethylene
Tetrachloroethylene
Methoxychlor
PCB— Total
1 ,2,4-Trichlorobenzene
2,4-D
2,4,5-T
1,2-Trans Dichloroethylene
Diethyl Phthalate
DI-N-Octyl Phthalate
Bis-2(Ethyl Hexyl) Phthalate
Di-N-Butyl-Phthalate
Toluene
1 ,4-Dichlorobenzene
DSS
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
MISA 47-POTW
X
X
X
X
X
X
X
X
x
X
X
X
X
X
X
X
X
X
X
X
X
X
X
x
X
X
X
X
X
X
X
X
X
X
X
X
X
x
X
X
X
X
X
X
X
x
4-19
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estimates in'DSS, EPA assumed an activated sludge treatment plant meeting secondary
discharge standards, receiving a steady feed of each pollutant at 500 ppb. Pollutant loadings
reported in both the 47-POTW and MIS A data bases, however; vary across a range of
concentrations that does not approximate the conditions DSS assumed for acclimation.. The
fact that the 47-POTW and MISA data did not approximate the, 500 ppb influent wastewater
concentration used by EPA-WERL should not be surprising^ EPl performed statistical
analysis of influent concentrations of seven metals in Determining National Removal Credits
for Selected Pollutants for Publicly Owned Treatment Works (EPA, 1982a), based on data
from the 40-POTW Study. That document presents average influent concentrations for seven
metals at 39 POTWs. Of the 273 averages^-one for each of the 7 metals at 39 plants—only
• 15 metal concentrations were at least as large as 500 ppb, with 9 of these being for zinc,
Furthermore, the majority of the 273 concentrations are less than 100 ppb, as shown below:
Metal
Cadmium
Chromium
Copper
Lead
Nickel
Silver
Zinc
Number With
Avg. Infl. <100 ppb
37
16
.13
29
. 30
39
1
Number With
Avg. Infl. >500 ppb
1
1
1
1
2
o
' . ' . 9 .. ,'.
Comparisons were made to the estimated median removal values in DSS, which provide
a central representation of pollutant removals. Where analytical data in the 47-POTW or
MISA data bases indicated influent or effluent pollutant concentrations to be below detection
limits, removals were calculated using one-half the analytical detection limit as the surrogate
pollutant concentration in order to prevent surrogate values of zero for pollutant levels cited
as below detection.
All calculated negative removals (i.e., pollutant concentrations that were higher in
effluent than influent) were included in all data sets and analyses. (In general, negative
removal occurs when effluent concentrations indicate that more of a given pollutant is present
4-20
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in effluent than is present in influent.) Although some pollutants may be formed through
catabolic processes during secondary treatment, this.could not account for negative removals
for metals, and it is unlikely that this phenomenon alotie is sufficient to explain the observed
negative removals for the wide range of organics being evaluated.
Two hypotheses could explain negative removals: (1) sampling procedures may not
account for the hydraulic detention time of the POTW and, hence, may not be representative,
and (2) nonsteady state conditions may prevail at the POTW. The following paragraphs
provide more detail on each of these hypotheses. .
. Hydraulic Detention Times - In most cases, POTWs conduct simultaneous composite
sampling of plant influent and effluent and grab sampling of sludge. Even when samples are
composited over a period of 1 or more days, the sampling may fail to account for hydraulic
detention times and the impact of any internal recycle streams within the treatment plant.
The extent to which monitoring data included in the 47-POTW data base and the MIS A study
address hydraulic detention times and recycle streams and the extent to which these factors
may account for the calculated negative removals, could not be determined.
. Nonsteady State Conditions - Nonsteady state conditions usually prevail at
wastewater treatment plants. Steady state is a condition in which the input loading of a
particular pollutant (the influent loading) equals the combined output loading of that pollutant
(equal to the sum of the effluent loading, the sludge loading, and biodegradation and
volatilization losses). Nonsteady state conditions, the inevitable result of variable influent
loadings, are induced by (1) changing flows to the treatment plant, (2) perturbation of
physical process equilibria, such as sludge sorption/desorption, and (3) alteration of
biodegradation kinetics. Nonsteady state conditions may also be brought about by variations
in such plant operating characteristics as aeration rates, sludge recirculation, and wasting
rates. As with hydraulic detention time, the extent to which nonsteady state conditions
existed at the POTWs being examined could not be evaluated based on available data.
4.3.3.1 Analysis of Secondary Wastewater Treatment Plant Pollutant Data
The removal efficiencies calculated from the 47-POTW data base are given in Table 4-4
(calculations were performed only for pollutants for which there were at least five
observations). This table presents the number of observations (influent and effluent data
sets), the calculated average influent and effluent pollutant concentration, and the calculated
4-21.
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average removal efficiency for eaich plant. Table 4-5 allows for more ready comparison of
calculated removal efficiencies across plants for each pollutant.
Table 4-5 shows that where data were provided for more than one treatment plant, the
range of average removals was quite large. For example, average mercury removals ranged
from -85.6 percent to 77.3 percent, and average cadmium removal efficiencies ranged from
-1,362.5 percent to 73.9 percent. These data clearly suggest that pollutant removal at
secondary wastewater treatment plants is highly plant specific. Figure'4-2 represents these
data graphically. .
While Tables 4-4 and 4-5. provide interesting information into the .variability of removals
from POTW to POTW, they provide little insight regarding removals within individual plants.
Figures 4-3 through 4-7 present the distribution of removal efficiencies at the individual
POTW within the 47-POTW data base that was represented by the greatest amount of
.sampling data: .These figures illustrate the frequency with which removal efficiencies were
achieved across all reported sampling events (for copper, zinc, chromium, nickel, and lead).
While data for copper and zinc suggest mat some centralized tendencies might exist among
the reported removal efficiencies, this is not the case for chromium, lead, or nickel. These
data suggest that any calculations or decisions made regarding specific POTW removal
efficiencies should be conservative in nature and based on a comprehensive data set of
POTW-specific data.
To provide a broad measure of the comparability of removals data from the 47-POTW,
MISA, and DSS data bases, the median unacclimated removal estimates from the DSS were
plotted against the first and third quartiles of POTW average removal efficiencies calculated
from the 47-POTW data base and the MISA study. (Quartiles divide a data set into four
equal parts. Data points lying between the first and fourth quartiles represent the middle 50
percent of the data set, with the second quartile representing the median.) Appendices B-3
and B-4 present the complete set of pollutant removal frequency distribution and cumulative
frequency plots for the 47-POTW data base and the MISA study, respectively. Examination
of these distributions yields.the following observations: ,
• Frequency distribution plots of organics and metals data from the 47-POTW Study
revealed a wide dispersion of the data, with no trends being readily discernable.
.' • These wide dispersions suggest that single removal values, such as the median or
mean, would not appropriately reflect actual pollutant removals.
4-27
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1 Percent Removal Efficiency
Figure 4-3. In-plant Removal Efficiency Distribution for Copper from
One POTW in the 47-POTW Data Base
30
in
O
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20
10
_L
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Figure 4-4. In-plant Removal Efficiency Distribution for Zinc from
' One POTW in the 47-POTW Data Base
4-30
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09
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Figure 4-5. In-plant Removal Efficiency Distribution for Chromium from
One POTW in the 47-POTW Data Base
O
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Figure 4-6. In-plant Removal Efficiency Distribution for Nickel from
One POTW in the 47-POTW Data Base
4-31
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15
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Figure 4-7. In-plant Removal Efficiency Distribution for Lead from
One POTW in the 47-POTW Data Base
4-32
-------
• Frequency distribution plots for inorganics and metals data from the MISA data! base
also show wide dispersions. As was the case with the 47-POTW data, .these MISA
data suggest that such removals should not be represented by single values.
However, for 11 of the 16 organic pollutants plotted, over 75 percent removals were
, indicated. These organics represented both volatile and semi-volatile compounds.
• The 47-POTW and MISA data bases have 11 pollutants in common. Examination of
the frequency distribution plots showed that 8 of the 11 plots have overlapping
interquartile ranges. Of these eight, only three pollutants have median values that
fall reciprocally into the corresponding interquartile ranges. These observations do
not indicate clear similarities between the two data bases.
• The DSS estimates of median unacclimated pollutant removals cannot be considered
representative of the removals observed in either the 47-POTW or the MISA data
bases. In comparing DSS pollutant removals with the cummulative plots of the 47-
POTW and MISA data bases, only 7 of 18 pollutant parameters in the 47-POTW
data base and only 12 of 23 pollutant parameters in the MISA study fall within the
interquartile ranges. Only three DSS estimates fall within the interquartile ranges of
both data bases, •
' V-1
I
A previous study conducted by EPA, Determining National Removal Credits for
Selected Pollutants for Publicly Owned Treatment Works (EPA, 1982a), includes statistical
analyses of pollutant removals data and provides an appropriate point of comparison for these
observations. This study analyzed treatment plant removals data for cadmium, chromium,
copper, lead, nickel, silver, zinc, and cyanide, as reported in the 40-POTW Study (EPA,
1982b).
The purpose of the 40-POTW Study was to determine the fate and occurrence of priority •
pollutants at POTWs. The study, conducted in 1978, included extensive sampling at 40
geographically distributed treatment plants representing a variety of technologies, size
ranges, and industrial flow contributions.
The 40-POTW Study plants were selected if they operated at or near the efficiency
required to meet secondary treatment regulations, although not all of the plants always met
30/30 BOD/TSS discharge limitations. The study population included both secondary and
some advanced wastewater treatment facilities.
Since the 40-POTW Study population was different from that evaluated in this chapter
and different data editing rules were employed (e.g., in the way that concentrations below
detection limits were treated), difect comparison of the removal efficiency distribution
histograms is not appropriate. However, the results.of the analyses can be compared. The
4-33
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results of the statistical analysis in the removal credits study indicated wide dispersions in
observed removal efficiencies, with no readily observabletrends, these observations are
consistent with the examination of metals removals for the 47-POtW and MIS A data bases.
4.3.3.2 Approach for Characterizing Dispersed Pollutant Removals Data
The analyses provided in Subsection 4.3.3.1 suggest that removals can be quite variable
from POTW to POTW and from sampling event to sampling event at individual POTWs.
POTWs frequently take 8- or 24-hour composite samples of POTW influent and effluent
streams and grab samples of sludge to characterize pollutant content This method of
sampling may not account for POTW hydraulic detention times and recycle streams within the
treatment plant. In addition, POTWs are likely to be nonsteady state systems. As a result
of these complicating factors, the use of a single central value, such as the median, may not
characterize the observed dispersed removals adequately.
* ' *
Rather than relying .on the median or other measure of central tendency, it may be more
appropriate to characterize dispersions of removal efficiencies at POfWsby deciles. (A
decile is similar in concept to a median. Whereas a median divides an ordered data set into 2
equal parts, with half of the values less than the median and half greater, deciles divide an
ordered data set into 10 equal parts.. Ten percent of the data set values are less than the first
decile, 20 percent of the data set values are less than the second decile, and so on. The fifth
decile is equivalent to the median.) Although using deciles to estimate removal efficiencies
at a POTW would be no more likely to represent actual removal efficiencies than using
medians, selecting appropriate deciles would increase the probability that actual removals
were at least as efficient as the decile value used. This conservative approach would
increase confidence that actual efficiencies were not being overestimated (and, thus, that
greater pollutant loadings were passing through the plant) or in the case of sludge,
underestimated (in which case greater loadings than predicted would enter.the sludge). As
described in Chapter 5, the use of deciles to characterize removals has previously been
recommended in developing local limits (see, for example, EPA's Guidance Manual on the
Development and Implementation of Local Discharge Limitations Under the Pretreatment
Program [EPA, 1987]).
An approach using deciles rather than measures of central tendency could be equally
appropriate in national decisionmaking related to removal efficiency. Once deciles are
calculated for individual treatment plant data, estimates for use in national policymaking
4-34
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purposes might be derived from median values of selected decile removals from the subject
universe of treatment plants.;
A decile approach is generally more data-intensive than approaches that use measures
of central tendency. To calculate deciles, the number of'data points (i.e., the number of
sampling events at an individual POTW) must be sufficient to allow the division of individual
data sets into 10 equal parts; measures of central tendency, such as the mean or median,
require as few as one or two data points. This approach would greatly enhance the
confidence with which programmatic and policy decisions related to treatment plant
performance can be made at both the local and national levels.
4.4 FINDINGS ' • ' .
Toxic pollutants present in the raw sewage entering secondary treatment plants may
have several fates! Some toxic organic pollutants may biodegrade to varying extents. Those
that are not biodegraded are eilther partitioned to sewage sludge, volatilized at various
stages in the treatment train, or discharged to receiving waters. Metals are not biodegraded;
they either enter sewage sludges or remain in the POTWs wastestream and are discharged
in the effluent.
The removal of most toxic pollutants from wastewaters by POTWs is largely incidental
to the treatment of conventional pollutants and should be considered in terms of partitioning
among alternative pathways; pollutants may be shifted from one medium to another (to the
air through volatilization or adsorbed to sludge), as well as removed through biodegradation..
The DSS estimated percent removals of selected priority pollutants by municipal
wastewater treatment plants. These estimates, based on the research and BPJ of experts,
served in part as the starting point for additional calculations estimating national pollutant
loadings to air, sludge, and receiving waters. Values were presented for both "acclimated"
and "unacclimated" treatment systems.
The examination of removal efficiencies is important for two reasons: because the
loadings calculated in the DSS are based in part on estimated treatment plant removal
efficiencies (and subsequent loadings estimates) and because of the significance of treatment
plant removal efficiencies in various programmatic aspects of the pretreatment program.
4-35'
-------
Removal efficiencies may vary widely among and within POTWs.
r • , ' ''
• Examination of the individual data sets representing POTW removal efficiencies in
the 47-POTW data base indicated that very wide ranges of removals occurred for the
pollutants examined,
• Examination of POTW average pollutant removal efficiencies in both the 47-POTW
data base and the MISA data base indicated that POTW average removal efficiencies
are dispersed widely from POTW to POTW. For these two data sets, the average
POTW pollutant removal efficiencies could not be appropriately represented by any
single value. '
• MISA study data suggest that removals for a subset of organic pollutants (both
volatile and semi-volatile) occur within a narrow range in excess of 75-percent
removal. These pollutants were not representative of any single group of compounds
(volatile or otherwise) in the data base that might otherwise have explained the
trend. In contrast to ,the MISA results, analysis of the 47-POTW data suggests that
organics removals occur over a wide range, with no discernable trends.
i , "' „ ' • ' i >, „;.! , .'i „• • ; . •". |,M • 'I*!., mi .|, ',!' Wi*'. „,''• .iiifjlill,1*,,'1!!11,!1!'!!*1", .'i!1/'1" I*'"'! ' i':'l :",'1..' '"'!:"'!'!•,'- "iln, ".i,'.f i'lV.". , '^ - ' •. ii..I1!1,11" s1,,.!1*!,;:: 11:,;, i",.:, i ' ,,1,,:
• Analysis of data from one POTW within the 47-POTW data base (the plant having
the'most extensive data) suggested that removals of copper and zinc might be fairly
• ' consistent for that plant. However, no such consistency was observed for chromium,
lead, and nickel.
While the data contained in the data bases evaluated in this study sometimes extended Mfc
'beyond the list of priority, pollutants, the study methodology focused on pollutants having the
most extensive (and presumably more reliable) data sets; these pollutants were priority
pollutants, ,
The analysis of the MISA and 47-POTW data bases suggests that single-value,
national estimates of pollutant removal efficiencies provided in the DSS cannot be
appropriately applied to specific POTWs for either priority or non-priority pollutantsl This
finding is underscored by the variability in the sampling results within individual POTWs from
one event to the next. When these results are viewed in conjunction with the wide
dispersion of removals among different POTWs, the need for using POTW-specific data in
making decisions applicable to individual POTWs is emphasized.
Given the dispersed distributions of pollutant removals observed at secondary
treatment plants, EPA recognizes the need for more sampling data to be used in calculating
removal efficiencies. In addition, selection of representative pollutant removal levels based
on'a statistical confidence level would be more appropriate than the use of averages, this
4-36
-------
approach is consistent with current removal credits regulations which specify the use of a 75
percent confidence level, and EPA guidance on local limits.
Current EPA guidance allows POTWs to use literature values or other default values to
represent POTW conditions, including pollutant removals, for which POTW-specific data are
not available. The variability in observed pollutant removals, both across plants and from one
sampling event to the next at individual plants, suggests that the use Of literature values or
other default values in the calculation of local limits should be reevaluated. The observed
variability in pollutant removals suggests the need for more extensive POTW-specific
monitoring data as the basis for local limits calculations.
Finally, thfe finding that pollutant removals are widely variant among treatment plants
suggests that no single reference level for removals should be accepted at face value and that
the acceptability of Superfund remediation wastes discharged to POTWs must be evaluated
on a case-by-case basis. Such an evaluation would examine the overall acceptability of
using a given POTW as part of remediation activities and the level of protection afforded the
POTW and receiving environments with the appropriate environmental standards.
4-37
-------
" REFERENCES
1 . • , - • V. •: • ' < ' • , • ;, III ll i l
" • •' ' ', ''.':"'•>.' < i
'/',>,, T
. Bishop, D.F. Memo to T.P. O'Farrell, Estimation of Removability and Impact of RCRA
, Toxics, September 26,1985. '; ' [ - - :; ' '
Ontario Ministry of the Government 1988. Municipal/Industrial Strategy for Abatement.
Thirty Seven Municipal Water Pollution Control Plants. Pilot Monitoring Study. Vol. 1,
Interim Report.
U.S. Environmental Protection Agency. 1987. Guidance Manual on the Development and
Implementation of Local Discharge Limitations Under the Pretreatment Program.
Washington, DC: Office of Water Enforcement and Permits.
U.S. EPA. 1986. Report to Congress on the Discharge of Hazardous Wastes to Publicly
Owned Treatment Works. Washington, DC: Office of Water Regulations and
Standards. 530-SW-86-004.
U.S. EPA. 1982a. Determining National Removal Credits for Selected Pollutants for
Publicly Owned Treatment Works. Washington, DC: Office of Water Regulations and
Standards. EPA/440/2-82-008.
U.S. EPA.. 1982b. Fate of Priority Pollutants in Publicly Owned Treatment Works. Vol. 1.
• Washington, .DC: Office of Water Regulations and Standards, Effluent Guidelines
Division. EPA 440/1-82/303.
4-38
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5. CAPABILITY OF POTWs To REVISE PRETREATMENT STANDARDS
Section 519(a)(3) of the Water Quality Act of 1987 directed the U.S. Environmental
Protection Agency (EPA) to study "the capability of publicly owned treatment works
[POTWS] to revise pretreatment requirements under Section 307 (b)(l) of the Federal Water
Pollution Control Act" (FWPCA). Section 307(b)(l) required EPA to establish national
pretreatment standards to control the discharge to POTWs of pollutants not susceptible to
treatment by such works. This section also states that if the owner or operator of a POTW
can demonstrate that toxic pollutants are removed by the POTW and that such removal will
not prevent proper sludge management, then allowances reflecting these pollutant removals
can be applied to the industry-specific categorical standards established by EPA (i.e., the
POTW can grant removal credits).
The House of Representatives Committee on Public Works and Transportation, which
initially developed Section 519 of the Water Quality Act of 1987 (then referred to as Section
47 of HR 8), stated in the report transmitting this section that:
The Committee intends that EPA focus particular attention on the extent to
which EPA's pretreatment Removal Credits program is presently effectuating
the Congressional intent behind Section 307(b)(l). Congress added the credits
system to the Act in 1977 because of its concern that EPA's categorical
pretreatment standards could result in costly redundant treatment by industry
and publicly owned treatment works. The Committee also intends that, in
implementing Section (519[a][3]>, the Administrator shall examine the
capability of publicly owned treatment works to establish and enforce
requirements more stringent than or different from national categorical
standards (House Report No. 189, 99th Congress, 51 [1985]).
Allowing an industrial facility to discharge more of a pollutant than is permissible under
a national categorical pretreatment standard based on the percentage removal of that
pollutant by the POTW is referred to as granting the facility a removal credit. Limits
developed by a POTW based on a consideration of local environmental factors and
characteristics of the treatment plant are called "local limits."
EPA established a two-tiered study definition for the term "capability." In assessing
POTW capability to revise pretreatment requirements through the removal credits and local
limits processes, EPA is providing Congress with information on the availability of technical
objectives inherent to removal credits and local limits. EPA also has evaluated POTW
5-1
-------
capability to perform technical tasks critical to establishing and enforcing local limits and
removal credits. The first component of "capability" ensures consideration of POTW
capability to achieve the statutory and regulatory objectives intended for removal credits and
local limits, namely, eliminating treatment redundancy in an environmentally protective
manner and imposing more stringent local controls to meet site-specific plant and
environmental objectives, respectively. Thus, in evaluating capability to achieve technical
objectives, EPA is measuring how well these program components are fulfilling their original
objectives and is considering the availability of environmental criteria that are prerequisites.
I , • • ' : < , in iiiii i i i n
By contrast, the second "capability" component, capability to perform required tasks,
focuses on the abilities of POTWs to complete significant steps in developing and
implementing local limits and removal credits. Evaluation of this aspect of POTW capability
involves assessment of POTW aptitude and technical ability to perform more mechanical
functions, such as monitoring and limits calculations.
This two-tiered definition ensures consideration of POTW capability to achieve both the
ends and the means associated with local limits and removal credits. Section 5.4 fully
! ' ' ' ' . . ,, , ' ,„,!!'''''' , i' J, ''!,'" '!J,1i,' ' ,:!,!:"!!:' !'!!,',,'!!'",, " ' ,!"' ... „•'I1'1' ','' ,',"'' ,'"".. ' " , "'',!'!'!" '' !,',' !.!.' ''"
develops the methodology for this two-tiered approach. .
•: , '•' :• .'. v;. '" ,;.; ,;..:.,:: •..::•: •. •;'..;.:;::;." 'v.': :,;:;:
Section 5.1 provides an overview of pretreatment standards (national, State, and local),
how each type of standard works, and what industries and pollutants are covered by each
type of standard. Section 5.2 describes how removal credits and local limits are developed.
Section 5.3 summarizes and evaluates the extent of technical and environmental criteria and
standards, including water quality criteria, toxic effluent limits, sludge quality criteria, sludge
permit limits, and air quality criteria and emissions limits applicable to POTW wastestreams.
, li , « •. : • • ' ''„,"' '"''„', '• ' •,' ./"I,,, i''1 ''I ', •"!!•,, I,'".",!'1!',1!:!'' •, i'i Bni'.illili1 W,, ii 'i"'*,,.,, \i\ia v1 \r n ,f> ~«M, s*,' '\\:,:\ i; /i , ^ , T ,.,•.•,;• ,r:,|, i.j, •. ,,
Characterization of these criteria and limits is necessary because their adequacy and
existence influences the effectiveness and extent of the enyir^nr^^ guide
POTW development or revision of pretreatment standards. Section 5.4 describes the data
sources and methods used to evaluate POTW capability to revise pretreatment standards.
5" . ; : •• •. • • '_•__ " "• " ' • /'"SHi'MW; ;, wif li Kit "••» :Ki;r";:<'«:;'!••!"(•. ^.'i1 •• .•..11 ".' 'f ,'.,•(, U'O
Section 5.5 presents the assessment of POTW capability to revise pretreatment standards
through the granting of removal credits. Section 5.6 evaluates POTW capability to develop
and implement local limits. Section 5.7 summarizes overall findings.
5.1 OVERVIEW OF PRETREATMENT STANDARDS
The General Pretreatment Regulations establish three types of pretreatment standards:
prohibited discharge standards (40 CFR 403.5[a] and [b]), local limits (40 CFR 403.5[c]),
" ' • ' - ,i, , , • • ' i '• : ": ' .'nl
f f i *
, 5-2
-------
and categorical standards (40 CFR Parts 405-471). The following subsections describe
these standards briefly, .
5.1.1 Prohibited Discharge Standards
Sections 403.5(a) and (b) of the General Pretreatment Regulations establish the
general and specific prohibitions, respectively, that apply to all nondomesric users of POTWs.
The general prohibitions state that a "user may not introduce into a POTW any pollutant(s)
which cause Pass Through or Interference" (see Chapter 1). The specific prohibitions forbid
pollutant discharges that meet specific conditions, including the following:
(1) Pollutants that create a fire or explosion hazard in the POTW, including, but not
limited to, wastestreams with a closed cup flashpoint of less than 60°C (140eF)
. using the test methods specified in 40 CFR 261.21
(2) Pollutants that will cause corrosive structural damage to the POTW, but in no case
discharges with pH lower than 5.0, unless the works is designed specifically to
accommodate such discharges
. (3) Solid or viscous pollutants in amounts that will cause obstruction to the flow in the
POTW resulting in interference
(4) Any pollutant, including oxygen demanding pollutants (i.e., biochemical oxygen
demand [BOD]) released in a discharge at a flow rate and/or pollutant
concentration that will cause interference with the POTW
(5) Heat in amounts that will inhibit biological activity in the POTW resulting in
interference, but in no case heat in such quantities that the temperature at the
POTW treatment plant exceeds 40eC (104'F) unless the approval authority, upon
request of the POTW, approves alternate temperature limits'
(6) Petroleum oil, nonbiodegradable cutting oil, or products of mineral oil origin in
amounts that will cause interference of pass through
(7) Pollutants that result in the presence of toxic gases, vapors, or fumes within the
POTW in a quantity that may cause acute worker health and safety problems
(8) Any trucked or hauled pollutants, except at discharge points designated by the
5.1.2 Local Limits
Local limits are developed to implement the prohibited discharge standards at a
particular POTW. They are developed by the POTW based on site-specific data and may
apply to both the categorical and noncategprical industrial users of the POTW.
5-3
-------
5.1.3 Categorical Standards
Effluent limitations guidelines are national, uniform, technology-based effluent
standards promulgated by EPA that apply to all industrial facilities in selected industrial
categories. Effluent guidelines that restrict pollutants mat pass through or interfere with
POTWs are referred to as categorical pretreatment standards. Effluent guidelines, including
categorical standards, are developed by EPA's Industrial Technology Division (ITD) and are
based on the capability of available treatment technology. Categorical standards are
''' ' . . , , i ', , • ! , il> ii :in<<< .1'iii.i"!! '. V'Riil i'" ,i, »i I','1,, ' "' •' ., ! "II ',i l,,l 1" i ,' "'i'1 . " i, u'1'.i'i ." i1 . .:,' , ' ;!', i,r'i , \ ']" H ,:||n'
expressed as Pretreatment Standards for Existing Sources (PSES) or Pretreatment
Standards for New Sources (PSNS); they are published, along with effluent guidelines for
direct dischargers, in 40 CFR Parts 405 through 471.
? Categorical standards may not be sufficient in themselves to protect a specific POTW
from pass through and interference; therefore, they are supplemented by prohibited discharge
standards and local limits. The following subsections report on the status of categorical
standards, summarizing some of the information introduced in Chapters 1 and 3.
5.1.3.1 Current Standards
The list of industries subject to categorical standards has changed as a result of court
decrees, settlement agreements resulting from litigation, and EPA* s development activities.
Table 5-1 lists all industrial categories currently subject to categorical standards, either
for new or existing sources or both. Tables 5-2 and 5-3 identify the pollutants regulated by
each category. The number of toxic pollutants regulated for any industry category is variable,
as the tables show. For example, the Builders' Paper and Board Mills category regulates
only two of the 126 priority pollutants, while the Organic Chemicals, Plastics, and Synthetic
Fibers category regulates more than 40. It should be noted, however, that not all industrial
categories discharge all toxic pollutants; standards are established only for those identified
as pollutants of concern. In addition, the treatment technology upon which the standards are
based often achieve treatment of other pollutants in the wastewater. Rather than
establishing standards and requiring monitoring for all pollutants potentially present, EPA
often has established standards only for indicator pollutants.
Chromium and zinc are the most frequently regulated toxic pollutants; they are regulated
for 16 of the 34 categories with toxic standards. .Phenol, tetrachloroethylene, toluene, and '
naphthalene are the four most frequently regulated toxic organic pollutants; phenol is
5-4
-------
Table 5-1. Industrial Categories with Pretreatment Standards for
Existing Sources (PSES) and Pretreatment Standards
for New Sources (PSNS)
40 CFR Part
467
AS\^t
427
A ^-i
461
A i -i
431
458
A ^e
465
468
469
A + S\ ' '
413
412
424
A "1 O
418
A*\f
426
Af\£
406 .
.| A^f
447
415
420
A*\e
425
AS*S\
433
* ' A f A
464
j4^f •!
471
y« A -f
421
,J -f A
414
A A S*
446
j< >l 1
443
>• i /\
419
439
A £f
466
,« f*g\ .
430
428
j *
417
yf^O
423
A/\f\
409
429
PSES
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-,
X
X
X
X
X
X
PSNS
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Industrial Category
Aluminum forming
Asbestos manufacturing
Battery manufacturing
Builders' paper and board mills
Carbon black manufacturing
Coil coating
Copper forming
Electrical and electronic components
Electroplating
Feedlots
Ferroalloy manufacturing
Fertilizer manufacturing
Glass manufacturing
Grain mills manufacturing
Ink formulating
Inorganic chemicals
Iron and steel manufacturing
Leather tanning and finishing
Metal finishing
Metal molding and casting
Nonferrous metals forming and metal powders
Nonferrous metals manufacturing
Organic chemicals, plastics, synthetic fibers
Paint formulating
Paving and roofing materials
Petroleum refining
Pharmaceutical manufacturing
Porcelain enameling
Pulp, paper, and paperpoard
Rubber manufacturing
Soap and detergent manufacturing
Steam electric power generating
Sugar processing
Timber products processing
5-5
-------
Table 5-2. Consent Decree Industrial Categories With Categorical Pretreatment Standards
.' '! i ' i •' ,' ' i ' I' i . i , i'1 . ' I' ' ' • ' III I II I I I
Priority Pollutants
AcenophtTKine
Acrolain
AcrylonitrilB
Benzene
BenzWlne
Carbon Tetrachloride (Tetrachloromethane)
Chtorobenzene
1 ,2,4-Trichiorobenzene
HexKhtorobenzene
1 ,2-Dlchloroe thane
1,1.1-Trlchloroethane
Haxachloroa thane
1,1-Dlchloroe thane
1 ,1 ,2-Trichforoethane
1,1,2,2-Talrachloroolhane
Chforoethana "
Bi«(2-ch!orofllhyl) Ether
2-CMoroethyI Vinyl Ether (mixed)
2-ChtoronaphthaIene
2,4.6-TrIchlorophenol
Parachtorometa Cresol
Chtorolorm (Trichloromethane)
2-Chtorophenol
1 ,2-Dichloro benzene
1 ,3-Dichloro benzene
1 ,4-Dichlorobtnzeno
3,3-DichtorobenzIdine
1 ,1 -Dichtoroethylene
1 ,2-Trans-dich!oro«thyltne
2,4-DJchtorophenol
1 ,2-Dichloropropans
1 ,3-Dichkjropropylane (1 ,3-Dichloropropene)
2,4-Dimethylphenol
2,4-Dinitrotoluont
2,6-Dinltrotoluene
1 ,2-Diphenylhydrazlne
Ethylbenzene
Fluoranthene
4-CWofophenyl Phenyl Ether
4-Bramophenyt Phenyl Ether
Bit (2-Chtofoljoprapyl) Ether
Bii (2-Chloroathoxy) Methane
Methytene Chloride (Dichloromethane)
Methyl Chloride (Chloromethane)
Methyl Bromide (Bromomethane)
Bromoform (Tribromomethane)
Dichlorobromomolhane
Chlof o
-------
Table 5-2. Consent Decree Industrial Categories With Categorical Pretreatment Standards
Industrial Category (40 CFR Part)
2,4-Dinitrophenol
N-Nitrosodimethvlamine
N-Nitrosodiphenvlamine
N-nitrosodi-n-propvlamine
Pentachlorophenol
Bis (2-Ethylhexyl) Phthalate
Butyl Benzyl Phthalate
Dimethyl Phthalate
3enzo(a)anlhracene (1,2-Benzanthracenel
3enzo(a)pyrene (3.4-Benzopyrene)
3enzo(b)fluoranthene 3.4-Benzofluoranthene
3enzo(k)fluoranthane (11,12-Benzofluoranthenei
Benzo(ghi)perylene (1.12-Benzoperylenel
Fluorene
Dibenzo(a.rOanthracene (1.2.5,6-Dibenzanlhracene)
Indeno (1.2.3-cd) Pyreno (2.3-o-Phenvlenepyrene)
Tetrachloroethvlene
Trichloroethvlene
Vinyl Chloride (chloroethvlenel
Chlordane (technical mixture & metabolites)
4,4-DDD (P.P-TDE1
Alpha Endosulfan
Heptachlor Epoxide
Alpha-BHC (Hexachlorocydohexane)
Gamma-BHC (Lindanel
PCB-1242 (Arochlor 1242)
PCB-1254 (Arochlor 1254)
PCB-1232 {Arochlor 12321
PCB-1260 (Arochlor 12601
PCB-1016 (Arochlor 1016)
Toxaphene
(TTO), "P--NO discharge in detectab.e amounts,
-------
Table 5-2. Consent Decree Industrial Categories With Categorical Pretreatment Standards
,i "Hll ,1". ,» "I,!,'
„ . , ' ' • • ' '''„., ''*!'"' r J' ' '',;''" ''i "'i^i1"' i1'" Hi "3' 'f iiii1!. • ', ' r'lfj. '!'' 5".''i''. i' • •'! i' 'l! !',i"1'."1!" r iii'i i "!,!„ i|' "i ! Vi,..r "•,[ ill':'1' !•.' ;i! ,",' ,.'"!'' '•'" ', ^Kjl'^i-l'il^Bviijii'V
Priority Pollutants
Ltad (Total)
Nick*) (Total)
2,3,7,8-Tetraehlorodlbanzo-p-dloxln (TCDO)
OTHER REGULATED POLLUTANTS
Ammonia, (ai N)
Chromium. Haxavatent
Cobaft
Cyanld*, Amenable
Fluorid*
Gold
Iron
Mifioan***
Molybdtnum
Oiaod Gr*u«
Othtr pMtiddas
Palladium
Photphorous
Phlhalat*
Platinum
Sulfkl*
Tantalum
Tin
Titanium
Total Matali
Tunoslen
Industrial Category (40 CFR
467
X
X
X
X
461
X
X
X
X
X
X
X
X
X
X
X
4«S
X
X
X
X
X
X
X
X
X
46S
X
X
X
X
X
X
46«
X
X
X
X
X
X
X
413
X
X
X
X
X
X
X
X
T
X
X
41S
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
420
X
X
X
X
X
X
X
425
X
X
433
X
X
X
X
X
X
X
'
X
T
X
464
X
X
X
X
471
X
X
X
X
X
X
X
X
X
X
X
X
421
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
414
X
X
X
Part)
418
X
X
X
439
X
466
X
X
X
X
430
X
431
423
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
428
X
X
X
X
"X"-Numerical standard, ""P-Regulated as part of total toxic organics (TTO), "P"-No discharge in detectable amounts,
"R"-Standard has been remanded. 5.3
-------
Table 5-3. Noniconsent Decree Industrial Categories With
Categorical Pretreatment Standards
Priority
Pollutants
Chromium (total)
Cyanide
Lead
Phenols
Zinc
Other Regulated
Pollutants
Ammonia (as N)
Chromium (hexavalent)
COD
COD/BOD 7
Fluoride
Manganese
, Nitrate (as N)
Oil & Grease
Oil (mineral)
Organic Nitrogen
Phosphorus
No Discharge
of Process
Wastewater
Pollutants
406
X
Category
409
X
412
X
417
X
X
418
X
X
X
X
X
424
X
X
X
X
426
X
X
X
X
427
X
428
X
X
X
X
447
X
458
X
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regulated for nine categories while the other three are regulated for eight categories. Six of
the 14 categories withi standards for organic pollutants address total toxic orgariics.1
In addition, 12 categories have a "no discharge" standard (effectively, a standard of
zero for all pollutants) for specific manufacturing processes. Another 12 categories have
standards for toxic pollutants only for new facilities.
5.1.3.2 Categorical Standards Under the 304(m) Process
On January 2, 1990, EPA responded to Section 304(m) of the Clean Water Act (CWA)
by publishing its agenda for revision and review of existing effluent guidelines for direct
dischargers and promulgation of new effluent guidelines (55 FR 80). At the same time, EPA
described its plans for reviewing, revising, and promulgating categorical pretreatment
standards. EPA has decided to revise categorical pretreatment standards for existing and
new sources in the Organic Chemicals, Plastics, and Synthetic Fibers category (1993), the
Pharmaceutical Manufacturing category (1994), and the Pulp, Paper, and Paperboard category
(1995) because some toxic pollutants discharged from these industries are not regulated by
current pretreatment standards. In addition, EPA is assessing the need to revise categorical
pretreatment standards for the Petroleum Refining category, the ximlber products Processing
category, and the Textile Mills category.
Furthermore, EPA intends to promulgate pretreatment standards for existing sources
(PSES) and pretreatment standards for new sources (PSNS) for the Pesticide Chemicals
category (1992), the Hazardous Waste Treatment—Phase 1 category (1995), and the
Machinery Manufacturing and Rebuilding category (1995). Processes in these categories
generate large quantities of toxic pollutant loadings to POTWs that often exceed loadings
from industrial categories already subject to pretreatment standards and effluent limitations.
Finally, EPA plans to study the following industrial categories to determine the merit of
1. Total toxic organics is defined as the sum of the masses or concentrations of specific toxic
organic compounds in the industrial user's process wastewater at a concentration greater
than 0.01 milligram per liter (mg/1).
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developing effluent guidelines (including categorical standards), which could affect thousands
of facilities that discharge toxic pollutants to POTWs:
* Drum Reconditioning
• Hospitals
• Industrial Laundries
• Paint Formulating •
• Solvent Recycling
• Stripper Oil and Gas Extraction
• Transportation Equipment Cleaning
• Used Oil Reclamation and Refining.
5.2 POTW REVISIONS TO PRETREATMENT STANDARDS
Congress has requested an evaluation of POTWs' capability to revise or establish
pretreatment standards. This chapter reviews the. steps involved in developing and
implementing removal credits and local limits.
5.2.1 Removal Credits Development and Implementation
Removal credits are mechanisms by which POTWs may adjust federally established
categorical .pretreatment standards to reflect pollutant removals demonstrated at a POTW,
\ " ' • , • • '
assuming the POTW meets other environmental criteria, such as the POTW's National
Pollutant Discharge Elimination System (NPDES) permit limits, sewage sludge use/disposal
criteria, and local limits. The purpose of removal credits is to eliminate the need for ,
costly, redundant industrial pretreatment in cases where the local POTW provides some
measure of treatment for the regulated pollutants.
Currently, the removal credits provisions of the General Pretreatment Regulations (at
40 CFR 403.7) are suspended until the comprehensive sludge disposal regulations of 40 CFR
Part 503 are promulgated. For the purposes of describing the removal credits development
process in this subsection, the approach defined in the regulations at 40 CFR 403.7 (although
currently suspended) will be used.
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The current removal credit provisions of 40 CFR 403.7 specify that a POTW must do the
following before it can be authorized to grant removal credits to categorical industrial users:
, •• , ,',,"„,., „, «'
• Apply for authorization to grant removal credits from the approval authority
• Demonstrate consistent removal of the pollutant for which a removal credit is being
sought
• Have an approved pretreatment program or qualify for the exception to this
requirement
• Maintain compliance with applicable Federal, State, and local sludge disposal
requirements "
• Maintain compliance with its NPDES permit limits and conditions.
An eligible POTW may apply to the approval authority at any time for authorization to
give or modify such credits. The approval authority must review the application in accordance
with the procedures listed in 40 CFR 403.11, which are the same procedures used to review
pretreatment program submissions. The approval authority must complete the review and
respond to the POTW within 90 days from the date of public notice of the submission of a
request for removal credit authorization or 180 days if the public comment period is extended
or if a public hearing is held. After the approval authority has reviewed the application, it can
approve or deny the application, or it can authorize a lower removal credit than the POTW
sought.
Once the approval authority has approved a POTW's removal credit application, the
consistent removal rate documented in the application will be included in the POTW?s
NPDES permit upon the earliest reissuance or modification (at or following pretreatment
program approval) and become an enforceable requirement of the POTW's permit. The
approved removal rate will remain in effect for the term of the POTW's NPDES permit,
provided the POTW continues to meet the conditions for removal credit approval, including
maintaining consistent removal.
After removal credit authority has been granted for a particular pollutant regulated in a
categorical pretreatment standard, the POTW may automatically extend that removal credit
to other categorical standards where the same pollutant is regulated. Application of the
removal credit to other categories is conditioned upon continued compliance with both sludge
requirements and NPDES permit limits and conditions.
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Once the POTW has been granted authorization to give removal credits, it must
continue to monitor and report on its removal capabilities at least once per year. The
approval authority may require more frequent reporting. The report must include analytical
results for those pollutants for which removal credits were granted. A minimum of one
representative sample per month for the period covered is required for the report. Sampling
and analytical methods must conform to the requirements specified in the final removal credit
rule.
The following subsections discuss the application requirements in the order specified in
the removal credit provision. Appendix G-l provides an example removal credit calculation.
5.2.1.1 List of Pollutants
The application must list the pollutant(s) for which removal credits are proposed. These
pollutants may include any toxic or other regulated pollutant for which discharge limits are
specified in a categorical pretreatment standard. Some categorical pretreatment standards
use conventional or nonconventional pollutants as indicators or surrogates for-toxic
pollutants. Removal credits may only be given for indicator or surrogate pollutants regulated
in a categorical standard if me standard specifically allows removal credits.
5.2.1.2 Consistent Removal Data
The POTW's application must demonstrate consistent removal for each pollutant for
which a removal credit is being sought. With certain exceptions, discussed in the following
paragraphs, this demonstration must include analytical data from influent and effluent
samples and a calculation of consistent removal. Analytical data are required from at least 12
representative samples of influent and effluent taken at approximately equal intervals
throughout 1 full year.
"Consistent removal" is currently defined as the arithmetic mean of the lowest 50
percent of the removals calculated by the POTW. In other words, if 12 samples of influent
and effluent are collected, the removals for each of the 12 are calculated, and the average of
the lowest 6 is deemed "consistent removal." This means that removal at approximately a
75 percent confidence level is required.
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< Illlll
When pollutants are not measurable in some influent and effluent samples, the provision
* in . h i , . ,» ' , | i i, .' ,
-------
Many POTWs have more than one treatment plant receiving wastewater from industrial
users (lUs) regulated by categorical pretreatment standards. Removal rates must be
determined separately for each treatment plant. The POTW may then revise and regulate
separate limits for categorical lUs discharging to different treatment plants, or it may take the
most stringent limit (i.e., the limit that has been revised using the lowest removal rate of all
the plants) and use that as the limit for all Ills discharging to all plants. It is important to
note that the POTW must demonstrate a consistent removal rate for each pollutant at each
treatment plant that receives wastewater from Ills for which removal credits will apply.
5.2.1.4 Local Pretreatment Program Certification
The removal credit application must include a certification from the POTW stating that it
has an approved pretreatment program or qualifies for exemption from this requirement as
discussed below. The certification must be signed by an authorized POTW representative.
5.2.1.5 Sewage Sludge Management Certification
The POTW's application must specifically describe its current method to use or dispose
of its sludge and certify that granting removal credits will not cause the POTW to violate any
of the following Federal statutory provisions and regulations or permits issued to implement
them (or more stringent State or local regulations):
• Section 405 of the Clean Water Act -...'.'
• Solid Waste Disposal Act (SWDA), including Title H, more commonly referred to as
the Resource Conservation and Recovery Act (RCRA), and State regulations
contained in any State sludge management plan prepared pursuant to Subtitle D of
RCRA
• Clean Air Act
• Toxic Substances Control Act .
• Marine Protection, Research, and Sanctuaries Act.
To meet the requirements of this section, the POTW should demonstrate that it will
continue to comply with applicable sludge disposal regulations after the categorical standards
are revised. This demonstration involves determining the increase of the pollutant in the
sludge that will result from the standard's revision.
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5.2.1.6 NPDES Permit Limit Certification
The final application requirement is a certification that granting removal credits will not
cause a violation of the POTW's NPDES permit limits and conditions. Alternatively, the
POTW can demonstrate that even though it is not currently in compliance with its NPDES
permit, it will be in compliance when its industrial user(s) are required to meet the categorical
pretreatment standards (as modified by the removal credit provision). Either demonstration
involves calculation of the anticipated increase of the pollutant concentrations in the influent
to the treatment plant and the resulting effect on treatment processes and effluent.
Where the POTW's NPDES permit does not have toxic pollutant limits, the POTW
should check that water quality criteria or standards (if applicable) will continue to be met
after the categorical standards are revised.
5.2.1.7 Removal Credits Implementation
Once consistent removal is established, and the industrial users' revised standards
have been calculated, the POTW must implement the revised standards through its system of"
individual control mechanisms. This is usually done by revising existing industrial user
( . • , , • -. •• • , , '':• ,i . > K/V'jfi;i<; :• -.' ,,,' . ',.•
-------
modified drinking water standards; it may adopt categorical standards, such as metal finishing
limits; or it may adopt limits based on literature findings. None of these methods, however,
specifically addresses the fundamental purposes of local limits defined previously, which are
to prevent adverse effects to the POTW, to the environment, and to public health. To address
these concerns, which are highly site-specific, the POTW must conduct a comprehensive
evaluation of its operational and environmental characteristics and develop protective local
limits based on this evaluation.
The predominant approach used by POTWs and advocated in EPA's Guidance Manual
on the Development and Implementation of Local Discharge Limitations Under the
Pretreatment Program (EPA, 1987a) (hereafter called "EPA's Local Limits Guidance") is a
pollutant-specific approach known as the maximum allowable headworks loading (MAHL)
method. This method involves back-calculating from environmental and plant protection
criteria to develop MAHLs. This is accomplished, pollutant by pollutant, for each
environmental criterion or POTW requirement The lowest or most limiting value for each
pollutant serves as the basis for allocation to industry and ultimately setting local limits. The
following subsection describes the use of MAHLs in developing local limits.
5.2.2.1 Maximum Allowable Headworks Loading Method
Determinin Pollutants of
EPA's August 1985 policy memorandum identified six pollutants of potential concern to
all POTWs— cadmium, chromium, copper, lead, nickel, and zinc— because of their occurrence
in POTW influents and effluents in concentrations that warrant concern. EPA's Local Limits
Guidance identifies four additional pollutants — arsenic, cyanide, silver, and mercury — that all
POTWs should consider, unless an analysis of their wastewater and sludge shows that they
are not present in significant amounts. The policy memorandum also states that POTWs
should collect data on priority, conventional, and nonconventional pollutants reasonably
expected to be discharged to the POTW in quantities that could pass through or interfere with
the POTW treatment process, contaminate the sludge, or jeopardize worker health and safety
or the collection system.
Generally, the POTW should perform at least one priority pollutant scan and possibly a
scan for RCRA ground- water monitoring parameters (in Appendix DC of 40 CFR Part 264) to
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• . • , ,• ii " ,
identify potential pollutants of concern in the influent, effluent, and sludge. Once the POTW
has identified such pollutants, it should evaluate the need for a local limit for each.
Characterizing Existing Loadings
During the local limits development process, the POTW must characterize existing
loadings to the treatment plant. Local limits should be based on site-specific monitoring data
wherever possible. This can be accomplished by monitoring all industrial users. POTW
monitoring or industrial user self-monitoring data are both acceptable. The POTW may also
use information •from its industrial waste survey, a prerequisite to local program approval, in
which the POTW identifies all industrial users that might be subject to its pretreatment
program.
If hauled wastes are accepted at the POTW, they may be a significant source of
pollutant loadings or flows. In such a case, the POTW should consider the wastes in the
determination of local limits.
The POTW also should characterize domestic and other background loadings by
monitoring a representative portion of its collection system. Use of literature values is
generally discouraged. If used, these values should be justified in the POTW's submission.
The POTW must conduct sufficient monitoring at the treatment plant to characterize
influent, effluent, and sludge loadings for its pollutants of concern. Initial monitoring of the
treatment plant influent, effluent, and sludge should, at a minimum, represent 5 consecutive
days. Ongoing monitoring should include data for at least 1 day a month over at least a year
for metals and other inorganic pollutants, and 1 day of sampling a year for toxic organic
pollutants.
^Determining Applicable Environmental Criteria
Environmental criteria generally include NPDES permit limits, water quality standards
or criteria, sludge disposal requirements, and unit process inhibition values. The POTW
should use all applicable environmental criteria when developing local limits. Section 5.3
summarizes applicable environmental and technical standards and criteria. Additional
appropriate requirements may include worker health and safety criteria, collection system
effects, incineration emissions requirements, or other applicable Federal, State, or local
environmental protection requirements.
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Another less frequently used environmental criterion is biological toxicity. the July
1990 Amendment to the NPDES permitting regulations requires POTWs to submit the
results of biological toxicity testing with their permit renewal applications' (40 CFR
122.21 0]). POTWs that identify a problem through biological toxicity testing should develop
local limits to correct the toxicity. Although EPA's Local Limits Guidance does not specify a
method to calculate MAHLs based on the results of toxicity testing, additional guidance and
references on the Toxicity Reduction Evaluation process are available to PQTWs.
Calculating Maximum Allowable Headwbrks
The POTW must calculate the maximum amount (pounds/day) of each toxic pollutant
that may be contributed by an industrial user or received at the headworks of the treatment
plant that enables the POTW to meet all of the applicable environmental criteria. Figure 5-1
presents the formulae and data elements necessary to perform these calculations. In
addition, Appendix C-l presents a sample local limits headworks loading calculation.
Nonconservative pollutants , such as volatile organics require special consideration when
conducting headworks analysis (e.g., alternative formulas and allocation methods).
During this step of the local, limits development process, the POTW should demonstrate
that an acceptable mass balance exists between the actual loadings of pollutants at the
headworks and the estimated loadings of pollutants from specific discharge sources. This can
be accomplished by calculating the actual loading of each pollutant from influent monitoring
data and comparing this value with the sum of the estimated loadings from all individual
sources (e.g., domestic, industrial, hauled waste)
Calculating Allowable Tndnsfrfol Loadings
Once the POTW has calculated the MAHL, a safety factor should be applied and the
value discounted for domestic/background loadings to determine the maximum allowable
allocation available for industrial users. A safety factor is incorporated into the calculations
to allow for future industrial and residential growth and discrepancies that may enter into the
calculations because of the use of default data or variations in analytical procedures.
Generally, this safety factor ranges from 10 to 30 percent.
After the allowable industrial loading has been calculated, the POTW allocates this
loading according to the number and type of industrial users and the method of application
(sewer use ordinance and permits). Where the current loading of a pollutant exceeds, or is
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Figure 5-1. Equations for Deriving Allowable POTW Influent Loadings
From In-PIant Criteria
Tn-Plant Criterion
NPDES permit limit
Water quality standard
Secondary treatment (e.g., activated
sludge) threshold inhibition level
Tertiary treatment (e.g., nitrification)
threshold inhibition level
iii|in • '
Sludge digester
threshold inhibition level
Sludge disposal criterion/standard
where:
Mass Balance Equation
(8J4)(CCRIT)(QPOTW)
(8.34)[Cwo(CsTR
- (CSTR)(QSTR)]
•,.•••,? (1-RPOTW) ....-
IK " •, »,'jfrU'V •, 'ijI'BHil'NIli!" 'fri'lii'"! , i". ' i. i ',•!'i'l'i1'' «i 'i .«" -
(8.34)(CCRIT)(QPOTW)
(I-RPRIM)
(8.34)(CCRIT)(QPOTW)
:.,,.,,. Jl-RsBf?}.
^''(^^xgcRITXQDIGT1''' ""
(RPOTW)
(8.34)(CsLCRIT)(PS/100)(QDISP)
(RpOTW)
LIN = Allowable influent loading, Ibs/day
CCRIT = In-plant criterion, mg/l
CSLCRTT = Sludge disposal criterion/standard, mg/kg dry sludge
• "'ill ! j' !l !• ' ' iii i I/!' '!„, i ,„ 1 !':,': •,.',,.i'": ijp,' i;;1!"!!'1 J{,|iii!'lh|i|'!il!!l^:!l;;ii;,''li'ii,."'1..1:'i1 •:•',, .[ ',' ',,!,111|':1ST; ''HL «•' '• t :,•'.'': i • -" ,1°
QPOTW = POTW flow (million gallons per day)
RpOTW = Removal efficiency across POTW, as a decimal
QSTR = Receiving stream (upstream) flow, mgd
QSTR = Receives stream background level, mg/l
CWQ = Receiving stream water quality standard, mg/l
RpRIM = Removal efficiency across primary treatment, as a decimal
RSEC = Removal efficiency across secondary treatment, as a decimal
QDIG = Sewage sludge flow rate to digester, mgd
QDISP = Sewage sludge flow rate to disposal, mgd
PS = Percent of sludge to disposal.
Uniform concentration local limits can be derived through the use of the following equation:
CLIM =
(l-SF)(LiN)-LDOM
(8.34)(QiND)
where:
CLIM
LIN
SF
LDOM
QIND
Uniform concentration local limit, mg/l
Maximum allowable influent loading, Ibs/day
Safety factor, as a decimal
Loading for domestic/uncontrollable sources, Ibs/day
Total industrial flow, mgd.
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expected to exceed, the MAHL, the POTW must establish a local limit to reduce loadings to
within the range of the MAHL and protect against interference, pass through, and sludge
contamination.
A variety of procedures exist for the allocation of the allowable industrial loading. The
four allocation methods most frequently used by POTWs are:
• Uniform concentration - The MAHL for each pollutant is divided by the total flow for
all industrial users (even those that do not discharge the pollutant). The resultant
discharge concentration for each pollutant is applied to all industrial user discharges.
• Concentration based on industrial contributory flow - The MAHL for each pollutant is
divided by the flow from only those industrial users that actually have the pollutant in
their untreated wastewaters (in concentration greater than the background
concentration level). The discharge limit derived is applied only to those industrial
users that contribute the pollutant
• Mass proportion - The ratio of the MAHL to the current loading for each industrial
user contributing a particular pollutant is calculated, and the mass loading limit is
derived by multiplying this ratio by the industry's current pollutant loading. The limit
derived is unique for each industry, and limits are developed and applied only to
industries that contribute the pollutant.
• Selected industrial reduction - Individual pollutant loading reductions for each
industry are determined; typically the loading reductions are based upon the
treatabUity of the industrial wastewater for each pollutant.
The uniform concentration method is the industrial loading allocation method most
frequently used by POTWs. It Is the only method identified above that results in local limits
that .are the same for all industrial users. The other three methods can be termed industry-
specific. The POTW must employ best professional judgment to evaluate the relative
advantages and disadvantages of each method and to select the most appropriate method to
allocate the allowable loading to account for differences, such as the treatability of industrial
wastewater or the current loading from different industrial facilities. A few POTWs have
been known to use a "market forces" approach to allocate the MAHL, in which all industrial
users have been gathered together to allow them to negotiate allocations. Regardless of the
allocation approach used, the POTW must ensure that the resulting local limits will be
enforceable and ensure protection of the treatment plant from interference and pass through.
Revising Local Limits
Many factors on which these local limits calculations are based may vary with time, and
local limits must be revised periodically to reflect changes in conditions or assumptions (such
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as changes in environmental criteria, availability of additional monitoring data, new sources of
pollutants, and changes in POTW processes, capacity, or configuration). 40 CFR 122.21
(j)(4) requires all pretreatment POTWs to submit a written evaluation of the need to revise
local limits as an application requirement for NPDES permits.
Implementing Local Limits
Once local limits have been developed, they must be incorporated into the sewer use
ordinance and/or some form of individual control mechanism, such as permits. Local limits
may be more stringent than categorical standards for a particular user. The POTW must
compare all applicable standards and apply the most stringent to each user. The POTW also
may elect to apply both local limits and categorical standards at separate sampling locations.
1 i >, '• • . • •: '. ;',"''.• i," .'",!';,/{! ',".<• i II!VMJT:W, :/ *,•,.-. ir „:»•:,(;; \ :a-.\' '•• • i . i''.M in>
This comparison of local limits and categorical standards often involves complicated
mathematical adjustments to account for dilute and unregulated flows; thus, POTWs may
have difficulty in applying the correct standard
5.2.2.2 Other Local Limits Approaches
POTWs have used other methods of local limits development, including the collection
system approach, industrial user management practice plans, and case-by-case discharge
limits. These approaches are described below briefly. EPA has published extensive
guidance on the development and implementation of the local limits. Further information on
each of these methods and the MAHL method can be found in EPA's Local Limits Guidance.
Collection System Approach
To apply this method, the POTW identifies pollutants that may cause fire and explosion
hazards or other worker health and safety concerns. Pollutants found to be present are
evaluated for propensity to volatilize and are modeled to evaluate their expected
concentration in air. Comparisons are made with worker health exposure criteria and lower
explosive limits. Where values are of concern, the POTW may set limits or require
development of management practices to control the pollutants. The collection system
approach may also consider the prohibition of pollutants with specific flashpoints to prevent
discharge of ignitable wastes.
Industrial User Management Practice Plans
Under this approach, POTWs require industrial users to develop management practices
as enforceable pretreatment requirements for the handling of chemicals and wastes. Such
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plans include chemical management practices and spill prevention plans. Management
practice plans are usually narrative local limits.
Case-hv-Case Discharge Limits ,
In this approach, a POTW may set numeric local limits based on best professional
judgment and on the performance of available technologies known to be economically feasible.
This approach is most often used when insufficient data are available to employ the other
methods above.
5.3 ENVIRONMENTAL AND TECHNICAL CRITERIA
Environmental and technical standards and criteria developed by approval authorities
are necessary prerequisites to setting local limits and revising categorical standards through
removal credits. As noted in Chapter 1, the Agency has developed a number of regulatory
programs, including the NPDES permitting program and the sludge management program, to
control point source discharges and the deleterious impacts associated with sewage sludge
disposal. These programs seek to limit in municipal permits the mass or concentration of
pollutants that can enter the environment from POTW wastestreams. Regulators rely on
numerous environmental standards, criteria, and regulations to set municipal environmental
objectives. These tools are used, in turn, by municipalities charged with developing or
revising local limits. Appendix C-2 contains some of these references, including:
• EPA's water quality criteria
• EPA's proposed pollutant limits for sewage sludge use and disposal. «
The appendix lists the number of States that have EPA-approved water quality standards
and air emission regulations. With respect to the pretreatment program^ criteria are also
necessary to ensure that the POTW treatment facility, its collection system, and those
individuals who work in close proximity to these facilities are protected from adverse impacts
of exposure to toxic pollutants.. This section provides a brief overview of these environmental
criteria arid standards, along with observations about their adequacy.
5.3.1 Water Quality
In order to protect the integrity of our Nation's waters, Congress has established
specific attainment goals that State and Federal regulations are directed to accomplish. To
meet these goals, EPA publishes water quality criteria for use by States in establishing
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water quality standards that protect the intended uses of receiving water. The NPDES
permitting program was established in part to implement these criteria and standards.
•',: ', - , ' • • ,";" :!.'•'• ,,:; '''••' -' '" i '' i'|i
5.3.1.1 Criteria and Standards
Under Section 304(a) of the Clean Water Act, EPA must develop water quality criteria
based on the most recent scientific knowledge:
• • f ','•"'•':' i • i i i ii 11
(A) of the kind and extent of all identifiable effects on health and
welfare, including ...plankton, fish, shellfish, wildlife, plant life,
shorelines, beaches/esthetics, and recreation which may be
expected from the presence of pollutants hi any body of water,
including groundwater; (B) on the concentration and dispersal of
pollutants, or their byproducts, through biological, physical, and
chemical processes; and (C) on the effects of pollutants on
, biological community diversity, productivity, and stability,
including information on the factors affecting rates of
eutrbphication and rates of organic and inorganic sedimentation
for varying types of receiving waters. .
In addition to establishing these criteria, EPA must develop information on protecting
the integrity of water, fish, and wildlife and the use of water for recreational activities.
Criteria and information developed must be made available to States and the public.
EPA requires States to develop water quality standards under 40 CFR Part 131. A
water quality standard defines the water quality goals for that water body by designating how
the water may be used and by setting numeric levels necessary to protect the uses. State
water quality standards submissions must describe the following:
« Water use designations
• Methods used and analyses conducted to support water quality standards revisions
• Water quality criteria sufficient to protect the designated uses
• An antidegradation policy.
Separate criteria are derived for the protection of aquatic organisms and human health.
Estimation of health risk requires predicting the effect of low doses for up to a lifetime. Two
methods are used to formulate human health criteria, according to whether the most
prominent effect for a pollutant is cancer or a noncancer effect. The first method involves
extrapolation of cancer responses from high doses over short periods to low doses over
longer periods. The second method (for noncarcinogenic adverse effects) estimates
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concentrations not expected to produce adverse health effects, based on acceptable daily
intake and derived using no-observed-adverse-effect-level data from animal and human
health studies.
EPA's water quality criteria are compared to concentrations of pollutants in receiving
waters. If aquatic concentrations exceed these criteria, there is a reasonable chance that
adverse effects could occur or are occurring in the water body. Thus, water quality criteria
serve as a general guide for "acceptable" environmental quality.
,," ' , --. • i _
The Water Quality Act of 1987 specifically required States to develop numeric
standards for toxic pollutants that could be expected to interfere with the designated uses of
the waters of the State and for which Federal water quality criteria had been developed. The
average number of priority pollutants with standards adopted for aquatic life uses has risen
from 10 (April 1986) to 30 (February 1990) per State; between 1986 and 1990, the number of
States with at least some aquatic life standards adopted increased from 33 to 45 (55 FR
14350). However, overall progress has been slow. As of the February 4, 1990 statutory
deadline, only 6 of 57 States and Territories (Montana, Oklahoma, Oregon, Wisconsin, Guam
and Virgin Islands) had complied fully with requirements for adoption of approved water
quality standards.
Since many States failed to adopt water quality standards by the February 4, 1990,
statutory deadline, EPA is developing applicable standards for noncomplying States. Table
5-4 lists the number of States with water quality standards for priority pollutants.
5.3.1.2 implementation (NPDES Permitting Program)
To implement the CWA's water quality goals, the NPDES permitting program
establishes requirements for all point source discharges, including POTWs. The permit
establishes the allowable volume and quality of the discharge into surface waters. Typically,
NPDES permits to POTWs contain specific limits for conventional pollutants (e.g.,
biochemical oxygen demand [BOD], total suspended solids, fecal coliform) and some
nonconventional pollutants (e.g., ammonia). In the past, however, regulation of toxic
pollutants occurred through a narrative toxicity prohibition (e.g., no toxics in toxic amounts).
Recent information obtained from the Permit Compliance System (PCS) data base has
5-25
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Table 5-4. Number of States and Territories With Water Quality
Standards for Priority Pollutants
Priority Pollutant
Acenapthene
Acrolein
Acrylonitrile
Benzene
Benzidine
Carbon Tetrachloride
Cholorbenzene
1 ,2,4-trichlorobenzene
HexacWorobenzene
1,2-dichloroethane
1 ,1 , 1 -trichloroethane
Hexachlorethane
1,1-dichlorethane
1,1,2-trichlorethane
1 , 1 ,2,2- tetrachlorethane
Chloroe thane
Bis (2-chloroethyl) ether
2-chloroethyl vinyl ether
2-chloronapthalene
2,4,6-trichlorophenol
Parachloromcta cresol
Chloroform
2-chlorophenol
1,2-dichlorobenzene
1,3-dichIorobenzene
1,4-dichIorobenzene
3,3-dichlorobenzidine
1,1-dichloroethylene
1 ,2-trans-dichloroethylene
2,4-dichlorophenol
1,2-dichloropropane
1 ,2-dichloropropylene
2,4-dimethylphenol
2,4-dinitrotoIuene
2,6-dinitrotoluene
1 ,2-diphenylhydrazine
Ethylbenzene
Fluoranthene
4-cUorophenyl phenyl ether*
4-bromophenyl phenyl ether
Bis (2-chloroisopropyl) ether
Bis (2-chloroethoxy) methane
Methylene chloride
Methyl chloride
Methyl bromide
Bromoform
Dichlorobromomethane
Chlorodibromomethane
Hexachlorobutadiene
Hexachlorocyclopentadiene
Isophorone
No. States
w/Standards1
Adopted
16
17
17
21
23
20
18
8
19
20
19
17
1
18
19
1
17
5
4
19
16
22
20
18
18
19
15
19
9
20
6
17
14
16
7
16
18
17
3
4
15
3
17
16
15
19
19
17
20
18
17
No. States
w/Standards1
Adopted/Expected
. i .
31
34
33
44
38
41
36
11
35
40
41
33
2
35
36
1
33
8
5
35
30
39
34
35
35
38
31
41
14
36
8
32
28
33
8
32
35
34:
5
6
31
9
36
33
32
37
37
35
•37
34
33
5-26
-------
Table 5-4. Number of States and Territories With Water Quality
Standards for Priority Pollutants (continued)
Priority Pollutant
Naphthalene
Nitrobenzene
2-nitrophenol
4-nitrophenol
2,4-dinitrophenol
4,6-dinitro-o-cresol
N-nitrosodimethylamine
N-nitrosodiphenylamine
N-nitrosodi-n-propylamine
Pentachlorophenol
Phenol
Bis (2-ethylhexyl) phthalate
Butyl benzyl phthalate
Di-n-butyl phthalate
Di-n-octyl phthalate
Diethyl phthalate
Dimethyl phthalate
1,2-benzanthracene
Benzo (a) pyrene
3,4-benzofluoranthene
1 1 , 12-benzofluoranthene
Chrysene
Acenaphthylene
Anthracene
1,12 benzopyrylene
•luorene
'henanthrene
1,2,5,6-dibenzanthracene
ndeno (1,2,3-cd) pyrene
*yrene
retrachloroethylene
Toluene
frichloroethylene
Vinyl chloride
Aldrin
)ieldrin
Chlordane
4,4-DDT .
4,4-DDE
4,4-DDD
Alpha-endosulfan
leta-endosulfan
indosulfan sulfate
indrin
indrin aldehyde
[eptachlor
[eptachlor epoxide
Alpha-BHC .
Jeta-BHC
Gamma-BHC (lindane)
Delta-BHC
No. States
w/Standards1
Adopted
8
18
6
7
17
14
16
15
8
27
33
23
12
22
10
.21
22
15
16
15
15
15
14
15
15
14
15
16
15
15
20
20
20
19
40
39
38
37
17
18
36
36
23
- 41
13
37
16
19
19
38
7
No. States
w/Standards1
Adopted/Expected
10
34
8
9
33
37
•J+4
32
31
11
46
43
~+J
38
13
*-iJ
37 '
+J f
12
34
«^T
36
Jvl
34
" «^T
36
*J\J
34
mf^
34
•^T
•34
«J*T
33
34
•J^
34
J~
33
•JfJ
34
J"
35
+J*J
34
*^T .
34
J~
40
"TV
38
• fJ\j •
42
39.
51
51
«/ ±-
50
bl\7
51
33
*s*J
*A
-'"
48
49 '
33
52
25
49
30
35
•36 '
51
10
5-27
-------
Table 5-4. Number of States and Territories With Water Quality
Standards for Priority Pollutants (continued)
Priority Pollutant
PCB-1242
PCB-1254
PCB-I221
PCB-1232
PCB-1248
PCB-1260
PCB-1016
Toxaphene
Antimony.
Arsenic
Asbestos
Beryllium
Cadmium
Chromium
Copper
Cyanide
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Dioxin (2,3,7,8-TCDD)
No. States
w/Standards1
Adopted
40 •
40
40
40
40
40
40
41
19
42
9
24
43
45
39
42
43
43
34
45
44
19
40
19
No. States
w/Standards1
Adopted/Expected
51
51
51
51
51
51
51
52
35
53
24
39
53
54
50
52
53
53
50
54
53
37
51
42
(1) State has numeric standards for one or more uses.
5-28
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revealed that of 1,865 treatment plants covered by an approved local pretreatment program,
only 400 (about 21.5 percent) had one or more chemical-specific limits for toxic pollutants in
thek NPDES permits.
EPA's emphasis on water quality-based (including toxicity-based) permits has
increased the number of NPDES permits containing specific water quality-based limits for
toxic pollutants (including whole effluent toxicity limits) (see Table 5-5). However, fewer
than one-third of all permits issued to POTWs contain any limits for toxic pollutants. For
example, ~of the NPDES permits issued to pretreatment POTWs that will expire in FY 1990
(generally issued in 1985), 21 percent had limits for toxic metals and 11 percent had limits for
toxic organic pollutants. Of the permits issued to pretreatment POTWs in FY 1989, 32
percent had limits for one or more toxic metals, and 11 percent had limits for toxic organics.
5.3.2 Standards for the Use and Disposal of Sewage Sludge
Section 405 of the Clean Water Act directs EPA to promulgate regulations and issue
permits for the use and disposal of sewage sludge in order to protect public health and the
environment from any reasonably anticipated adverse effects of these practices. These
regulations must identify sludge uses and disposal practices, specify factors that will be used
in developing standards and management practices for each specified use or disposal practice,
and identify concentrations of pollutants that interfere with each use and disposal practice.
EPA must establish numeric limitations for each toxic pollutant that may be present in sludge
at concentrations that may adversely affect human health and the environment. For each use
or disposal practi.ee, EPA may also specify the acceptable management practices for sewage
sludge containing pollutants of concern. To regulate these practices adequately and to protect
public health and the environment from reasonably anticipated adverse effects, EPA is
establishing numeric limits for a number of pollutants. Where such numerical limitations are
not feasible, EPA may specify design, equipment, management practices, or operational
standards.
5.3.2.1 Criteria and Standards
EPA proposed standards for the use and disposal of sewage sludge on February 6, 1989
(55 FR 5746). Standards are expected to be finalized as 40 CFR Part 503 in October 1991.
These proposed standards contain numerical pollutant limits or formulas for calculating such
limits for sludges that will be land applied, distributed and marketed, disposed of in amonofill,
5-29
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II SUI
"iflli'i
Table 5-5. Number of Limits for Toxic Pollutants in NPDES Permits Issued to
Pretreatment POTWs
Permits Expiring
in 1990*
Permits Reissued
in 1989
Total Number
of Permits
524
264
Number of Permits
With Metal Limits
0
412
(79%)
179
(68%)
1-3
36 (7%)
25 (9%)
Over3
76 (14%)
60 (23%)
Number of Permits
With Organic Limits
0
467 (89%)
236 (90%)
1-3
43 (8%)
19 (7%)
Over 3
14 (3%)
9 (3%)
These permits were generally issued in 1985.
Source: PCS (1990).
5-30
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disposed of in a surface disposal site, or incinerated. The proposed pollutant limits are listed
in Appendix C-2. The regulations also propose operation and management requirements for
each practice.
EPA proposed regulations under both the CWA and RCRA on August 30, 1988 (53 FR
33314), establishing siting, design, construction, and operation requirements for municipal
solid waste landfills. Under these proposed regulations (to be codified 40 CFR Part 258),
PQTWs would be able to dispose of sludge at landfills if, among other requirements, the
sludge is not a RCRA hazardous waste (e.g., it passes the toxicity characteristic leaching
procedure). ,
The proposed sludge standards do not cover ocean disposal. The Ocean Dumping Ban
Act of 1988 prphibits the dumping of sewage sludge into ocean waters after December 31,
1991. Until the few existing municipalities that dispose of sludge in die ocean have instituted
alternate disposal practices, this activity will be regulated by permits issued under the
Marine Protection, Research, and Sanctuaries Act
Until the proposed regulations are finalized, EPA will continue to regulate some aspects
of sludge use and disposal through existing regulations. For example, Part 257 addresses
land application of sludge, including co-disposal landfills and monofills, and 40 CFR Parts 60
and 61 govern air emissions from sludge incinerators. Part 257 limits the amount of cadmium
that may be land applied. It also establishes limits for the concentrations of eight toxic
metals, six organic compounds, nitrate, radium, arid microbes in ground water beyond the
boundary of the sludge disposal facility. Sludges that are hazardous wastes are regulated
under 40 CFR Parts 261 through 268. Sludges with a PCB concentration greater than 50
mg/kg dry weight must be disposed of under 40 CFR Part 761. Subsection 5.3.3 presents the
ak regulations relevant to sludge and POTWs.
States wishing to implement and enforce their own sludge program may seek program
approval from EPA similar to the way that States are authorized to administer other
environmental programs. Pursuant to Section 405, EPA promulgated the State sludge
management program regulations, which contain the programmatic elements that must be
fulfilled prior to EPA approval of a State program (40 CFR Part 501). The State sludge
management program must have the legal authority to require compliance with the standards
for sewage sludge use and disposal promulgated by EPA pursuant to Section 405 (see 40
5-31
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CFR 123.25[a][37] and 501.1[c][l]) unless the State enacts more stringent requirements
(see 40 CFR 123.25 and 501.1 [i] and &]).
5.3.2.2 Implementation (Sewage Sludge Program)
As described previously, the Agency is developing standards for the use and disposal of
-1-,' , • • i. „. .' ,' v.i,,! , .i, ,;..".-, "i " '" ••: ,i',,.»J'i;lfl!>i SMWKtd'**1'". i/tVlrltil-t-Jif1 •,!•*'it W U'l.r •!!!.(• I'v*,1 ,'*»'«* !.•«/':!" I1" IS
sewage sludge. To facilitate implementation of these regulations once they are final, the
Office of Water Enforcement and Permits has established regulations designed to incorporate
sewage sludge use and disposal requirements into permits, as required under Section 405(d)
of the Clean Water Act. On May 2, 1989, revisions to the NPDES permit regulations (40
CFR Parts 122, 124) and a new regulation (40 CFR Part 501) were promulgated. Revisions
to 40 CFR Part 122 address the inclusion of sludge conditionsunderthe; NPDES permit
program. The 40 CFR Part 501 regulations address sewage sludge conditions required for
inclusion in future State sludge management program permits. Both regulations require the
same minimum conditions, identified below, to be incorporated into NPDES permits or sludge
permits issued under the State sludge management programs:
• Duty to comply with Section 405 of the Clean Water Act
, • Statement specifying that Section 405 permit conditions are federally enforceable
under Section 309 of the Clean Water Act
• Reopener clause
• Duty to mitigate
• Permit actions—modification, revocation, and termination
• Notification requirements
• Statement specifying proper operation and maintenance of sludge use and disposal
facilities
• Inspection and entry
• Monitoring and report requirements
• Recordkeeping requirement.
EPA also developed a "Sewage Sludge Interim Permitting Strategy'' (EPA, 1989) to
ensure regulation of sewage sludge use and disposal practices by POTWs prior to the
promulgation of final technical standards. The interim strategy requires that all POTW
NPDES permits due for reissuance after February i987 be reissued with me standard sludge
conditions listed previously. In addition, recommended minimum monitoring requirements for
all POTWs are included in the Interim Strategy.
5-32
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The Interim Strategy also establishes a class of facilities requiring indepth analysis of
sludge use and disposal practices to determine if additional sludge conditions are required to
protect human health and the environment. It defines these Class I sludge management
facilities as POTWs that (1) are required to have pretreatment programs or (2) have any
other known or suspected problems with their sludge (e.g., POTWs using incinerators,
starting new .sludge operations, or having problems with sludge use or disposal). The Interim
Strategy advocates that the permit writer evaluate the Glass I facility and, if appropriate,
include additional permit requirements developed on a case-by-case basis to protect public
health and the environment.
A March 1990 report issued by the General Accounting Office (GAO) determined that
the implementation of the sludge management program was inadequate. GAO found that
State participation in the interim program is low and that EPA has not consistently issued
permits or permit riders that address sludge when States have failed to do so. The report
pointed out that EPA does not know how many permits being issued or renewed should or do
contain sludge conditions (GAO, 1990). EPA has taken steps to gather information on the
implementation status of the sludge management program.
5.3.3 Air Quality
Under Section 108 of the Clean Air Act, EPA must develop and publish a list of all
pollutants whose emissions cause or contribute to air pollution. For the pollutants listed,
EPA must develop air quality criteria that accurately reflect the latest scientific knowledge
about the identifiable effects of various amounts of these pollutants on human health. In
addition, EPA must issue information on air pollution control techniques to States and other
air pollution control agencies. These criteria are expected to be used by the States in setting
numeric specific air emission standards necessary to meet national primary and secondary
ambient air quality standards. Primary and secondary air quality standards are developed by
EPA and must be reviewed every 5 years. EPA also establishes new source performance
standards under Section 111 of the Clean Air Act and emission standards for hazardous
pollutants under Section 112.
Each State must adopt regulations addressing air emissions from sources located in the
State. State regulations, as well as all of the procedures necessary to ensure the proper
implementation and enforcement of the State-set standards, are contained in a State
Implementation Plan (SIP). States then adopt source-specific or area-wide numeric
limitations to ensure that the Federal (or more stringent State) ambient air quality standards
• •• •• , '•••'. 5-33 '-••'. •
-------
are achieved. EPA approves the SIP if the plan provides for attainment of primary ambient air
standards as soon as practicable and if it provides for attainment of secondary ambient air
quality standards within a reasonable time. In cases where the State does not submit a SIP,
or the SIP is inadequate, EPA is directed to develop an implementation plan on behalf of the
1 . : • " • •, / ' • i i ' - H
State.
The number of air pollutant emissions regulated at the State level is limited, consisting
primarily of paniculate emissions. Forty-one States regulate paniculate emissions from
sewage sludge incinerators. Of the eight States that 'do^0^'regulate ''^n^ va^xailaaioai&,
some may not have any incinerators. (One hundred sixty-seven municipalities incinerate
sludge at an average of about 3 per State.) Only seven States have emissions standards for
toxic pollutants, and they pertain only to mercury and beryllium. Hawaii is the single State
identified as having standards for volatile organic compound (VOC) emissions.
• ' •' '... ' .• . „ • .•: !.•;• >'„", • MI!'I'-i ..!•:.','. ••.'MIi.n' i' 'f ''.'(.i •• , :•.. ••; •»'.;, i:
. In general, POTWs are not regulated under existing air quality programs unless they
operate sludge incinerators. The Clean Air Act Amendments of 1990 require EPA to
promulgate emission standards for hazardous air pollutants from POTWs by October 1995.
11 "• 'i , • • „» . • "• ' ,; " 'i'i'ir1,! ,' 'iiii!'.,'!/, „!'•' ;' ! '"i".1' "i'V" ' • " li'ivi '" "!'i'' • ' •!,! : ,i,'• '•'<• •" J, • li'iviK/Mip'l
5.3.4 POTW Protection and Worker Health and Safety
When developing local limits, POTWs also must consider site-specific criteria designed
to protect the treatment works, the collection system, and workers from exposure to
pollutants. In general, these criteria consist of unit process inhibition criteria, technical
criteria regarding pollutant effects on various construction materials, and threshold exposure
criteria developed to protect human health.
Unit process inhibition criteria are pollutant concentrations that have been shown to
adversely affect the performance of the biological treatment processes used by POTWs.
These concentrations are determined by field observations of pollutant effects on actual
treatment systems and from laboratory and bench-scale testing of pollutant effects on
simulated treatment systems. The results of these studies (when they have been published)
have been summarized in EPA's Local Limits Guidance (EPA, l987a) as ranges of specific
pollutant concentrations that have demonstrated observable effects. POTWs may then use
these values to predict effects at their plants for similar processes. Currently, however,
these literature values are based on few data points and are available for only a few
treatment processes. If POTWs have experienced plant upsets and have quantified the
pollutant levels responsible for these effects, these site-specific values should be used.
'5-34
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With respect to collection system.'effects, POTWs generally rely on information1
provided by collection system manufacturers' to predict the pollutant concentrations that may
cause damage. In addition, some larger POTWs have performed in situ and bench-scale
testing of various construction materials to determine observable effects. The results of
these testing efforts are published in trade journals and manufacturers' literature but are not
provided in summary form.
Currently, the Occupational Safety and Health Administration (OSHA) does not cover
POTW workers. However, EPA has addressed POTW worker health and safety through
regulations and guidance. On July 24, 1990 (55 PR 30082), EPA expanded the specific
prohibitions to include additional prohibitions for explosivity and fume toxicity. While the
revised explosivity provision established a specific numerical standard (closed-cup flashpoint
less than 140°C), the fume toxicity provision.is a narrative prohibition. The principal reason
behind the narrative provision, as opposed to a numerical standard, is that fume toxicity is
difficult to quantify and often results from reactions occurring within the collection system or
collection system design. In addition, POTWs are advised in the Local Limits Guidance to
consider worker health and safety during the development of local limits.
5.4 DATA SOURCES AND METHODS
This section further delineates the two-tiered assessment, presented in the introduction
to this chapter, that evaluates the availability to the POTW of environmental and technical
criteria and the capability of the POTW to perform required technical tasks. By taking this
approach, the Agency could separate those elements of standards development or revision
beyond the control of POTWs (e.g., establishment of criteria and standards, and the technical
framework for standards revision) from those dependent on the POTW (e.g, ability to collect
data and perform calculations). In addition, this section provides an overview of the data that
were available and used to evaluate these capabilities.
5.4.1 Methodology Utilized to Assess POTW Capability
In establishing a methodology to evaluate POTW capability to develop or revise
pretreatment standards, the Agency first had to define "capability" in terms that would foster
analysis. It was clear from the outset of this investigation that "capability" could not be
defined simply in terms of how many POTWs had established a removal credits program or
had adopted local limits, because it was known that many of these POTW-revised standards
were not consistent with current regulation or guidance. In addition, "capability"
5-35
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" , •..-.' , I I , ll I I I lit,
encompasses not only those POTWs that have accomplished the defined tasks successfully
it , " i •"" ,;; i,i1 ;,'' : ,' i i" nil:.1.1:!.,;1';:':!1;,!!"'!,., i1 Jin1'!,,1 .in;'1"1!1!!' nl,," •' n" < M: ! "J1 ' i:"i, "i,!1""1!!!!1 v-i'!! ' • '"rf«" .,,'""I'1!1!1!:1:!1
but also those who could complete the tasks but have not yet done so.
. ••: • ' • ' '•-, •'• •• " i
The evaluation was structured to address each of these concerns. "Capability" was
divided into two components:, availability of technical objectives and capability to perform
required technical tasks. The first component evaluates the criteria and standards that drive
the revision process and determines whether they were sufficient to effectuate the intent of
the regulations. The second component evaluates whether or not POTWs were capable of
performing the individual tasks defined by these required processes. Figure 5-2 presents a
schematic of this two-tiered approach and indicates that if both components of the evaluation
were satisfied, then POTWs would be capable of developing or revising pretreatment
standards. The next step in developing the methodology was to determine the specific
technical objectives and technical tasks involved in the development of removal credits and
local limits.
Table 5-6 presents the technical objectives and the technical tasks that were identified
for developing removal credits and local limits. The individual technical tasks, listed below,
were grouped by general subheadings that were then used to organize the remainder of this
chapter:
• Collect requisite data
• Determine pollutants of concern
• Calculate pretreatment standards
• Apply pretreatment standards.
For consistency, these general groupings are used for the evaluation of both removal credits
and local limits. Figures 5-3 and 5-4 provide a diagram of the removal credits and local limits
development processes, with respect to these groupings.
5.43. Data to Assess Capability to Meet Technical Objectives
To assess the capability to achieve technical objectives, it is first necessary to establish
what these technical objectives are. To this end, EPA reviewed the regulatory history of the
National Pretreatment Program, the NPlSliS permitting strategy, and the environmental
criteria and standards for water, sewage sludge, and air. Additionally, EPA reviewed the
judicial challenges to the General Pretreatment Regulations, the court decisions in these
suits, and the statutory and regulatory response to the court decisions. Subsections 5.5.1
) ii*1: • /it in.: "i1.:/.'ft,!.''''j
5-36
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Are POTWs Capable of
Revising/Developing Environmentally
Protective Pretreatment Standards?
Technical Objectives
Are the principles and technical
considerations, including all applicable
environmental and technical criteria,
adequate to allow POTWs to
revise/develop environmentally
protective pretreatment standards?
Technical Tasks
Can the POTWs perform the
tasks required by regulations
and guidance in the development
or revision of pretreatment standards?
IF BOTH ARE SATISFIED
THEN POTWs ARE
CAPABLE
Figure 5-2. Evaluation Approach to Determining POTW Capability
to Revise/Develop Pretreatment Standards
'. 5-37
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Table 5-6. Technical Objectives and Technical Tasks Involved in the
Development of Removal Credits and Local Limits
Technical Objectives
*,
Technical Tasks
"
Removal Credits
• Does the removal credits
development process
ensure that indirect
discharges are treated to
the extent that would
otherwise be provided if the
discharge were direct?
• Does the removal credits
development process take
into account the ultimate
fate of the removed
pollutant?
Collect Requisite Data
• Characterize POTW
influent, effluent, and
sludge
• Obtain industrial waste
survey data
.'
Determine Pollutants of
Concern
• Identify applicable
standards and criteria
• Certify compliance with
. NPDES and sludge
disposal requirements
Local Limits
• Does the local limits
development process
ensure that POTWs
identify and regulate all
pollutants of concern?
• Are the environmental and
technical criteria, upon
which local limits are
based, in place for each
pollutant of concern?
Collect Reauisite Data
• Characterize POTW
influent, effluent, sludge,
and collection system
• Obtain industrial waste
survey data
• Characterize
industrial/commercial
sources
• Characterize contributions
from domestic sources
Determine Pollutants of
Concern
• Identify applicable
standards and criteria
• Identify POTW protection
criteria
• Analyze characterization
data in light of applicable
standards and criteria
5-38
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Table 5-6. Technical Objectives and Technical Tasks Involved in the
Development of Removal Credits and Local Limits (continued)
Removal Credits
Local Limits
Technical Tasks (continued)
Calculate Pretreatment
Standards
» Calculate pollutant
removals across the POTW
» Establish industry
discharge standards
» Prepare and submit
application to approval
authority
Calculate Pretreatment
Standards •.-•'.
• Calculate pollutant
removals across the POTW
• Calculate maximum
allowable headworks
loadings
• Establish industry
discharge standards
Apply Pretreatment
Standards
» Incorporate standard in
control mechanism
° Continue monitoring of
POTW pollutant removal
rates
« Implement compliance
monitoring and enforcement
activities
Apply Pretreatment
Standards
Incorporate standard in
control mechanism
Continue monitoring of
POTW pollutant removal
rates
Implement compliance
monitoring and enforcement
activities
5-39
-------
Collect Requisite
Data
Calculate Pretreatment
Standards
Apply
Pretreatment Standards
Quantify pollutant loadings in
POTW influent, effluent, and sludge
Determine applicable environmental
and technical criteria
Determine treatment plant "consistent removal" rates
Calculate revised pretreatment standards
Prepare submission and obtain approval
authority approval
Incorporate revised standards in
control mechanism
Implement compliance monitoring
and enforcement
Figure 5-3. Outline of the Removal Credits Development Process
5-40
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Collect Requisite
Data
Determine Pollutants
of Concern
Calculate Pretreatment
Standards
Apply
Pretreatment Standards
Identify and characterize sources of pollutants
Quantify pollutant concentrations and
loadings in POTW influent, effluent, and sludge
Determine applicable environmental and
technical criteria
Determine POTW pollutant removal rates
Determine POTW pollutant headworks
loading for each pollutant of concern
Select allowable loading allocation scheme and
establish local limits
Enter and review development process
by public and other interested parties
I
Incorporate pretreatment standards in control
mechanisms where applicable
Implement compliance
monitoring/enforcement program
Figure 5-4. Outline of the Local Limits Development Process
'5-41
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and 5.6.1 summarize this historical background for removal credits and local limits,
respectively. The history reveals the baseline technical objectives and the programmatic
responsibilities of POTWs.
5.4.3 Data to Assess Capability to Perform Required Tasks
EPA extracted and analyzed data from several sources to measure the capabilities of
POTWs to revise pretreatment standards. The data sources consisted of three national data
bases:
• GAO Pretreatment Survey
• Permit Compliance System (PCS)
• Pretreatment Audit Summary System (PASS).
\
Chapter 2 describes these data sources in more detail.
\ • .
EPA supplemented the information from the national data bases with information
obtained during routine oversight activities conducted by EPA Regions and States, including
available POTW local limits development documents and removal credit requests. EPA
analyzed local limits development documents that were prepared by 57 POTWs in EPA
Regions VI and IX as part of their local limits submittals to EPA for approval. They
contained information on the procedures used in the development of the limits, the data and
environmental criteria used to calculate the limits, and the resultant limits that were
determined from the evaluation. EPA reviewed 18 removal credit requests and summary
information on 6 others (i.e., 24 of the 28 submitted for approval). While these submissions
varied significantly in level of detail, they generally included a discussion of the basic
development procedures used, a summary of the data used in calculation of removal
efficiencies, and the resultant percent removal claimed.
EPA then extracted information from these data sources to measure POTW
performance of the technical tasks required for revision of pretreatment standards. Figure
5-5 lists the data sources consulted for evaluation of POTW capabilities and summarizes the
information obtained from them.
In general, it was assumed that if any significant percentage (e.g., greater than 20 to 25
percent) of the POTWs for which data were available were performing a specific technical
task successfully, that the "capability" to perform it was demonstrated for all POTWs. This
5-42
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is not to say, however, that the task will in all cases (or even in most cases) be successfully
accomplished by POTWs. Many factors, such as lack of resources, lack of political will, or
lack of general interest in performing the task, might result in its nonperformance. In other
words, the failure of a significant portion of POTWs to perform a task does not necessarily
demonstrate a lack of capability.
5.5 EVALUATION OF POTW CAPABILITY TO DEVELOP REMOVAL CREDITS
i, , iii a
The availability of technical objectives and the capability to perform technical tasks
required to develop and implement removal credits will be considered separately in
Subsection 5.5.2. To understand why these objectives and tasks are important, it is first
1 ',''!" , i ' "ii ' , • . ,'' " 'i!" •• I'1:: '''• ,'',•'":'•, ', ,' " ' I "" I" f' l' l ll l l l * l l l
necessary to consider the statutory and regulatory history of the removal credits process.
This history is provided in Subsection 5.5.1 preceding the capability evaluation.
5.5.1 History of the Removal Credit Program
5.5.1.1 Statutory History
Since 1972, the legislative amendments to the Clean Water Act and accompanying
historical records indicate that Congress expected EPA would not' requke (1) pretreatment of
n. ' '!" i ' ' i. 'iii. ' » ' " ' i' • ',',!'', .,., ,'' .'I" .j,1"' i iif if i1 ill i,' . nil II,I'Hi'1,, \i,l!',MIII||i'l|f!l|l^^ I 'hi. "' ,,1'j I'll .'III*"! I'.ii!,, n', IIU ., I ,,,|il Ifi"' ,i,ll'i,,,|li: ' liJi'i'i ',|ll ill,'
wastes that are compatible with the POTW treatment processes, and (2) pretreatment of
wastes by industrial dischargers for compatible wastes in lieu of adequate treatment on the
part of the POTW. This has been reaffirmed by each of the following statutory amendments:
• Federal Water Pollution Control Act Amendments of 1972 (33 U.S.C. 1251 et seq.)
• Clean Water Act Amendments of 1977 (P.L. 950217, 91Stat. 1566)
• Water Quality Act Amendments of 1987 (P.L. 100-4, 101 Stat. 60).
Section 307(b)(l) of the Clean Water Act Amendments of 1977 provides that a POTW
could be authorized to revise categorical standards for industrial sources contributing certain
toxic pollutants to reflect the municipal treatment work's removal of those toxic pollutants
under two conditions: (1) the combined removal of the pollutant by the POTW and the
industrial user equals or exceeds the removal .achieved by direct discharges, and (2) revision
of the standard does not prevent the POTW from using or disposing of its sludge in
accordance with Section 405 of the Clean Water Act,
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5.5.1.2 Regulatory History
EPA has conducted five rulemakings and issued one notice that have resulted in the
current removal credit provisions of the General Pretreatment Regulations:
• Pretreatment Standards, November 8, 1973 (38 FR 30983) (EPA promulgated as 40
CFR Part 128)
• General Pretreatment Regulations, June 26, 1978 (43 FR 27736) (promulgated as 40
CF# Part 403, replacing Part 128)
• General Pretreatment Regulations, January 28, 1981 (46 FR 9404) (revisions to Part
403)
• General Pretreatment Regulations, August 3, 1984 (49 FR 31212) (revisions to Part
403)
1 ' '••-',
• General Pretreatment Regulations, November 5, 1987 (52 FR 42435) (notice
regarding effect of partial judicial remand of August 3,1984, regulation).
The common elements of the removal credit rulemaking efforts include the following: (1)
authority wffl be granted only to POTWs that have applied for authority (industries cannot
apply for removal credits), (2) removal credits can only be granted for the percentage for
which the POTW can demonstrate "consistent removal" for each pollutant, and (3) to be
eligible for removal credits, the POTW must be in compliance with all applicable sludge use or
disposal practices. Rulemakings have included procedural requirements for contents of the
application, monitoring requirements and submittal of the application, public notice and
comment, followup reporting, application of the removal credit, and NPDES permit conditions
to incorporate the percent removal for each pollutant.
One portion of the regulation that has been revised frequently is the definition of
consistent removal. The successive regulations redefined consistent removal from- that
achieved 95 percent of the time (the lowest removal rate in any monthly sample [1978]), to
that achieved 75 percent of the time (the average of the six samples showing the least
removal [1981]), to that achieved 50 percent of the time (the average of all 12 monthly
samples [1984]). Pursuant to the decision by the U.S. Court of Appeals for the Third Circuit
in Natural Resources Defense f'nunril (NRDO v. U.S. EPA 790 F.2d 289 (3rd Cir. 1986)
invalidating this aspect of EPA's 1984 rules, the 1981 definition of "consistent removal" (75
percent) has been reinstated. (See 52 FR 42435.)
A second area frequently addressed in rule revisions is the relevance of POTW
combined sewer overflows (CSOs) to removal credits. The regulations have changed from
5-45
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requiring corrective action and minimization of bypasses (1978), to reduction of the removal
credit calculated based on the frequency of the overflow discharge, additional industrial
treatment, or suspension of discharge (1981), to deeming CSOs too insignificant to be
relevant to the availability of removal credits (1984). The Third Circuit's invalidation of this
portion of the 1984 Amendment reinstated the corresponding portion of the 1981 rule.
Court Challenges
Each rulemaking since 1978 has been challenged by industrial or environmental
organizations. Decisions from the United States Courts of Appeals for the Third, Fifth, and
Sixth Circuits have shaped the removal credit program. In its decision on NRDC v. U.S. EPA
790 F. 2d 289 (3rd Cir. 1986) cert, den.. 479 U.S. 1084 (1987), the Third Circuit invalidated
the 1984 regulations on four grounds:
• Defining "consistent removal" as "average removal" violated the statutory
requirement that credit be granted only if total removal equaled that required of direct
dischargers.
j " ' ' > "' , '" , !. " '•
• Ignoring the effect of CSOs violated the requirement of equivalent treatment of direct
and indirect dischargers.
. • The standards for modification and withdrawal of credits violated the Clean Water
Act. ' ' •...-•
• The Clean Water Act prohibits granting removal credits until POTW sludge disposal
regulations are developed under Clean Water Act Section 405.
Statutory and Regulatory Response to the Court Decision
On February 4, 1987, Congress enacted Section 406(e) of the Water Quality Act
Amendments of 1987, staying the Third Circuit's decision with respect to availability of
removal credits before sludge disposal regulations were prohibited. With respect to
availability of removal credits prior to EPA promulgation of technical sludge criteria, Section
406(e) stayed the Third Circuit Court decision until after August 31, 1987. On November 5,
1987, the Agency provided notice in the Federal Register clarifying that the 1984 rules
remained in effect except for the specific provisions invalidated by the Third Circuit Court of
Appeals. The notice stated that the 1981 regulations for these provisions were reinstated
and that the Agency would grant removal credits according to the regulations once sludge '
regulations were promulgated.
No POTW can be authorized to grant removal credits until sludge use or disposal
regulations applicable to its sludge practices are promulgated. Since the 1987 notice, the
5-46
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Agency has proposed two sets of sludge regulations, listed below, and has taken the position
that removal credits will be available for qualifying POTWs upon promulgation of either
regulation: '
• 40 CFR Part 258—Municipal Solid Waste Landfills (MSWLF) (53 FR 33314), to
establish siting, financial responsibility, and other management practices for non-
hazardous waste landfills
• 40 CFR Part 503—Standards for the Use and Disposal of Sewage Sludge (54 FR
5746), to establish numeric limits and management practices for pollutants disposed
of using specific practices, such as land application, distribution and marketing,
surface disposal, and incineration.
Under the Part 258 regulations as proposed, POTWs would be able to dispose of their
sludge in landfills that meet the requirements of Part 258 if, among other requirements, the
sludge was not a RCRA hazardous waste. If the Part 503 regulations are finalized as
proposed, removal credits will be available for the 70 pollutants with numeric criteria
identified in the proposed rule. An individual POTW will be eligible to apply for. a credit only
when a standard has been developed for the disposal option used by the POTW and the
POTW is in compliance with that standard. The proposed rule does not cover every pollutant
limited by a categorical standard. EPA expects to finalize the Part 503 proposal in October
1991.
Figure 5-6 illustrates significant developments in the history of removal credits.
Program Implementation
Rockfordj Illinois was the first POTW to receive authority to grant removal credits. The
May 30, 1984, approval (based on the 1981 regulations) gave Rockford the authority to grant
removal credits for six parameters regulated by categorical standards (chromium, copper,
lead, nickel, zinc, and total metals) for 38 categorical industries. Six additional applications
had been approved by July 1985 when the Agency published the Guidance Manual for the
Preparation and Review of Removal Credit Applications (EPA, 1985a). This guidance was
available to POTWs, EPA, and State personnel to assist in the development and review of
applications in accordance with the requirements of the 1984 removal credit regulations.
Thirteen applications were approved (Memphis, Tennessee, submitted a separate application
for each of its two POTWs) and 15 additional applications were pending when the Third
Circuit Court decision in 1986 invalidated portions of the 1984 regulations.
5-47
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In light of the Third Circuit's decision and Section 406(e) of the 1987 Water Quality Act,
all categorical industries contributing to POTWs that had received approval for removal credit
programs must be in compliance with categorical pretreatment standards, without
adjustment, at least until EPA promulgates sludge standards under CWA Section 405 and
the POTWs are approved to grant removal credits. This position has been upheld in court in
Armco. Inc. v. U.S. EPA (6th Cir. 1988) and CMA v; U.S.EPA /5th Cir. 1989). Table 5-7
identifies the applicant citie's and corresponding approval dates, and Table 5-8 lists the
pollutants for which removals were requested.
, • .• i • . •
5.5.2 Capability to Develop Removal Credits
As indicated in Subsection 5.4.1, the assessment of POTW capability is based on two
elements: availability of technical objectives and capability to perform required tasks. With
regard to the first element, the objective of Section 307(b)(l) and the removal credit
requirements at 40 CFR 403.7 is that the combined removal by an indirect discharger and a
POTW be consistent with the removal occurring under an effluent limitation or standard for a
source discharging directly to surface waters rather than through a POTW. With regard to
the second, the principal POTW tasks are here considered to be collecting data, identifying
pollutants of concern (and their sources), calculating revised standards, and applying the
revised standards as delineated in Table 5-6 in Section 5.4.
5.5.2.1 Availability of Technical Objectives
.The first element of EPA's assessment of capability focused on the following two
issues:
• Are indirect dischargers treated to the extent that is required of direct dischargers?
• Is the ultimate fate of the removed pollutant taken into account so that pollutants are
not merely transferred to another medium?
If these elements are sufficiently covered by the development process mandated by
regulation, then POTWs need only meet the regulatory minimums to ensure that the technical
objectives are achieved. . «•
Treatment Consistent With
The .principle underlying the granting of removal credits is that the combination of
industry and POTW wastewater treatment must be equivalent to that required of direct
dischargers in the same industrial category under the Clean Water Act. The direct discharge
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Table 5-7. Removal Credits Applications
!, . " . ', " ! ..I ,':,",".' '.MI''. I1'.1'. ',H,; " " '
••,i! .nQnjinnJiV''hi;;1,!!!,. ,•; ,.
POTW
Rockford, EL
Memphis, TN*
Sheboygan, WI
Speedway, IN
Gulf Coast Waste
Disposal Authority,
TX
Buffalo, NY
Milwaukee, WI
Kenosha, WI
Monroe Co., NY
Albuquerque, NM
Racine, WI
Galesburg, IL
Middletown, OH**
Sauget, IL**
Fond Du Lac, WI**
So. Milwaukee, WI**
Watertown, WI**
Grand Haven, MI**
Freeport, IL**
Chicago, 'IL**
Indianapolis, IN**
Tonawanda, NY**
Orange Co., CA**
Stockton, CA**
Berwick, ME**
Hartland, ME**
Manatowac, WI**
Approval Date
May 30, 1984
November 26, 1984
June 6, 1985
June 20, 1985
July 12, 1985
July 19, 1985
August .27, 1985
September 6, 1985
September 16, 1985
September 21, 1985
September 26, 1985
April 9, 1986
—
—
—
: —
—
—
' —
—
—
• —
• >
• —
• —
—
—
No. of Pollutants
Requested
6
10
1
2 .
2
7
1
4
7
8
5
1
2
6
1
1
5
1
5
10
11
1
—
—
1
1
5
No. of Industries
Affected
38
15
21
1
2
— •
15
9
38
unknown
2
1
1
3
10
unknown
4
1
unknown
321
51
1
—
—
1
1
16
*Memphis prepared two separate submissions for its two treatment plants. Numbers given represent sum of
both plants.
**Not approved at time of Third Circuit Court invalidation of removal credit program.
"—" Indicates submission was not available for review.
5-50
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Table 5-3. Pollutants for Which POTWs Requested Removal Credits
Pollutant
Arsenic
Cadmium
Chromium
Copper
Cyanide (T)
Cyanide (A)
Iron
Lead
Mercury
Nickel
Silver
Zinc
Total Metals
Ammonia
Oil and Grease
Phenols
Number of POTWs Applying
for Removal Credit Authority
2
• ,7
21
11
6
1
.1
10
• • 4
10
3
12
4
3
2
3
Percentage of Total
POTWs Applying*
8.3
29.2
87.5
45.8
25.0
4.2
4.2
41.7
16.7
41.7
12.5
50.0
16.7
12.5
. 8.3
23.1
*Based on data from 24 of the total of 28 removal credit submissions of which EPA is aware.
The remaining four submissions were not available for review.
5-51
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standards are based on best available technology economically achievable (BAT), best
conventional pollutant control technology (BCT), best professional judgment, and new source
performance standards (NSPS). Because they are technology-based, these numeric
limitations are established according to the level of wastewater treatment that can be
achieved. An assumption in determining the limitations is that the daily pollutant
measurements are lognormally distributed. Monthly limitations are based on the distribution
of averages of daily measurements. Li most cases, the daily maximum and monthly average
1 [' • ' , ''[ • ;''","" ! ''. ' i :' ! . IM
limitations are based on the 99th percentile of the distribution of daily measurements.
. I' • ' : ' ' ' ' I ' I . I
To achieve the technical objectives of Section 307(b)(l),,the combination of industry and
POTW treatment performance should provide treatment with the same level of consistency
as direct discharge standards. To ensure that this consistency is achieved, the Agency has
structured its removal credit regulations to require POTWs to demonstrate consistent
removal of pollutants for which credits are requested. As discussed in Subsection 5.5.1, EPA
initially (in 1978) required POTWs to collect 12 influent and effluent samples and to use the
most restrictive of the 12 removal efficiencies calculated to determine allowable removal
credits. This effort resulted in a credit being granted for removal achieved 95 percent of the
time, slightly less than that required by other technology-based standards. EPA
subsequently decided that this standard was unreasonably strict and likely to result in
redundant treatment. Therefore, the General Pretreatment Regulations were revised in 1981
to provide that consistent removal could be demonstrated by the average of the lowest 6 of
the 12 removal efficiencies calculated by the POTW (roughly equivalent to removal achieved
75 percent of the time). Because the regulation continued to be criticized as unworkable,
EPA modified the General Pretreatment Regulations in 1984 to define consistent removal as
that demonstrated by the average of all samples, which would allow credit based on removal
50 percent of the time. As discussed in Subsection 5.5.1.2, the Third Circuit Court of Appeals
determined that the new definition was mconsistent with congressional intent; thus, the
75-percent definition from the 1981 regulation was reinstated.
In addition to invalidating the definition of consistent removal, the Third Circuit Court
determined that the 1984 regulations did not adequately consider the impact of CSOs, which
undermined the intent of Section 307(b)(l) regarding treatment consistent with direct
dischargers.
Currently, while both BAT (direct discharge) and PSES (indirect discharge) standards
are set such that the applicable technology can meet the limit 99 percent of the time, a
• • • '5-52-.' ' ',"'''''":'" " ' """
-------
PQTW's demonstration of "consistent" removal for purposes of removal credits does not
require the same degree of confidence. Since a POTW pursuing removal credits for its
industrial users need only show removal that it can achieve 75 percent of the time, its
treatment combined with its industrial users' treatment may be less than that provided by
direct dischargers. Additionally, the regulations do not provide that POTWs with combined
sewers provide treatment consistent with that of direct dischargers. The demonstration of a
POTW.'s consistent removal must also be seen in light of the extreme variability associated
with POTW removals demonstrated in Chapter 4 of this report.
Environmental Protection
Pollutants reaching POTWs have four possible fates:
• Degradation (physical, chemical, or biological)
• Volatilization to air
• Discharge to receiving stream
• Partition to sewage sludge.
To protect environmental quality, standards or criteria governing each of these potential
pathways should be considered with respect to the pollutants for which removal credits are
sought.
Generally, pollutants that are degraded by biological treatment processes and are not
toxic to die microorganisms that provide treatment to conventional wastes are suitable for
removal credits. In addition, those pollutants that are reactive (physically or chemically) and
are incidentally removed through conventional treatment are also suitable for credits. To be
fully protective, however, it must be clear that these pollutants are not discharged to the
receiving stream, sludge, or atmosphere in quantities that could degrade the environment.
Therefore, standards for these media should be in place to ensure compliance.
For volatile pollutants, conventional biological treatment processes can transfer these
pollutants from wastewater to the atmosphere. The current General Pretreatment
Regulations do not specifically address the removal of pollutants by the POTW through
volatilization; thus, credits could be granted under these regulations without consideration of
5-53
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volatilization. This is contrary to the position in the Conference Committee Report on the
1987 Water Quality Act, which stated:
The purpose of removal credits under section 307(b)(l) is to
allow reduced pretreatment requirements on the basis of
treatment consistently achieved by the publicly owned treatment
works. Evaporation into the air of toxic organic compounds does
not constitute treatment of these pollutants. Consequently,
removal credits cannot be issued for such pollutants on the basis
of their evaporation from treatment works (132 Congressional
Record H 10577 [daily ed. Oct. 15, 19861).
In the preamble to the final Organic Chemicals, Plastics, and Synthetic Fibers
regulation, the Agency cited this reference in its decision not to consider volatilization as
removal for the purpose of determining whether BAT removals exceeded POTW removals
(52 FR 42547). The removal credit regulation, however, was based on the language of
Section 307(b)(l) itself, which requires consideration of the effects of removal credits on
sludge quality but not on the ah* medium. In contrast, however, one rationale for allowing
11 '. , '
removal credits for volatile pollutants is that denying removal credits would not in itself
prevent the industrial facility from meeting its pretreatment standard by using technologies
that transfer the pollutants to the atmosphere.
The remaining pathways for the release of pollutants from POTWs (discharge through
POTW effluent and sludge) are regulated under State and Federal discharge permitting
programs, in particular, the NPDES permitting program. As discussed in Section 5.2, these
programs have, in fact, primarily regulated the discharge of conventional pollutants, and only
about 21 percent of these permits contain ,one or more toxic limits. Permits are also required
to contain limitations on the disposal of sludge. However, the Agency's comprehensive
sludge regulations (40 CFR Part 503) are currently being developed; until these regulations
are final, there are few regulatory controls for sludge disposal.
Based on the above considerations, the existing removal credits framework is
appropriate with respect to pollutants degraded during conventional biological treatment.
Current regulations are silent as to whether removal credits may be authorized for volatile or
semivolatile pollutants, and additional regulations would be required if removals due to
volatilization are to be excluded from consideration. As to sludge and water, it is imperative
that comprehensive environmental criteria or standards be in place to ensure that removals
will not result in environmental degradation. According to the review of existing standards
5-54
Ji,1!' llllllCIVUKll'jll
'''i.',:1',!,!,'!,!!*11!,,
-------
and criteria in Section 5.3, it is evident that environmental controls for most toxic pollutants
are generally not comprehensive (i.e., they do not exist for all pathways), nor do they in each
case regulate all pollutants for which removal credits have been sought.
5.5.2.2 Capability to Perform Required Tasks
The evaluation of POTW capability to perform required tasks is keyed to the four
development and implementation phases discussed in Subsection 5.4.1:
• Collection of requisite data
• Determination of pollutants of concern
• Calculation of revised standards '
• Application of revised standards.
The following sections review POTW success in performing these tasks.
Collection of Requisite Data
Identifying Categorical Industries .
To apply for the authority to grant removal credits, a POTW must identify all categorical
industries that may benefit from an adjustment to categorical standards based on
demonstrated treatment plant removals for a particular pollutant. PASS indicated that 71
percent of POTWs identified their categorical industries correctly. Because removal credits
would relax standards for affected industries, and industries have incentive to cooperate in
the process, the success rate in identifying affected categorical industries for purposes of
removal credits is likely to be higher than 71 percent.
Demonstrating Consistent Removal
Removal credit regulations require demonstration of consistent removal to be based on
12 monthly sampling events. Of the 12 removal credit applications EPA analyzed that
contained detailed sampling information, 8 based their calculations on at least 12 sampling
events of treatment plant influent and effluent. The remaining four POTWs calculated
removals based on from one to six sampling events.
When considering POTW capability to collect at least the 12 samples required by the
regulations, EPA also regarded the statistics assembled on local limits submittals, in which
POTWs used an average of 13 influent, 11 effluent, and 7 sludge samples to support removals
5-55
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calculations. These data indicate that, in general, POTWs have the capability to collect the
required 12 data sets for removal credits purposes.
Determination of Pollutants of Concern
The pollutants of concern in the removal credit process are those for which a POTW
intends to pursue an adjustment of categorical standards. With respect to removal credits, no
,, a 'I. ! ,,, '., , . • • . ";, I ' ^hi '!' ',; „ n , ; ,,, , ! | ;,,,'.'i,;:,,»ii|
meaningful POTW capabilities are assessed in this step because the pollutants are limited to
those regulated in the categorical standard intended for adjustment
Calculation of Revised Standards
As shown in Subsection 5.2.1 and Appendix C-l, calculating removal credits to reflect
demonstrated pollutant removals requires POTWs to apply a simple formula to arrive at a
revised categorical standard. Following this revision, the POTW must prepare an application
for approval authority review containing the revised standards and certification statements
regarding continued compliance with applicable criteria and standards for approval authority
review. The revised categorical standard is then placed in the industrial user control
mechanism. Review of the 24 removal credit submittals did not reveal any significant POTW
deficiencies in the calculation of removal efficiencies or 'removal'credits, or in the preparation
of the applications. EPA is confident that POTWs have received adequate support and have
the capability to perform the calculations necessary to develop removal credits and to prepare
submissions in accordance with applicable regulations.
'WKSi-'irtft'l1 ,'t
J'li1""!, ii
Application of Revised Standards
According to PASS, 61 percent of POTWs have incorporated applicable pretreatment
standards into control mechanisms. While this indicates> that most PpTWs are capable of
this function, it is clear that many POTWs have had difficulty with this application. This may
,, i : °iV " ' T " „ „ ' , I1 i, II1 " " ' r • '';• „ 'I!'1' . , • „ • "i!i jhiMii'/iii'ilU'l1'!, .-':.-" , ':, •",:";•".•
the Domestic Sewage Study (DSS) regulations. The recent DSS revisions to the General
Pretreatment Regulations included provisions requiring POTWs to issue individual control
mechanisms containing all applicable pretreatment standards to each of their significant
industrial users; thus, this task should be more fully implemented in the future.
All of the activities performed in the development of removal credits preceding this step
. . •:,':• >> ' ' ,'; ' , : '-I-' , [P. I',1,: V ' •.'.'„: .!:'.,>;',''i-Ii':«V, ' >' .11! lISIll!!* ''',(!',''.'.it! W1'! ,'J i >i CM''. i,1/ t : i,J' ; .'*
are of limited use if the POTW fails to implement a compliance monitoring and enforcement
' ' ,i]j; f .' ' •„ , '„!:,".', i.V.'.;il ,"'.,: V-'.'i .:?•' 'Hiftf'WW'ifjiilpftlUKaVji ••! I.^Wft. ' '•.:(,• •'.;:„ ••,!
program. Annual POTW sampling and inspections of significant industrial user discharges
•• ,i .. ' ,• i i ,.•'•' r;.,..!'i .•""i,.!:,t"j>f3ftfi'• ,;> 'i;'1 •;!«•.*iwr *t. ,>• ,:;••'•• i^
are required of POTWs with approved pretreatment programs by the July 1990 Amendments
5-56
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to the General Pretreatment Regulations. PASS indicates that, from 1986 to 1989, only
50 percent of POTWs had both sampled and inspected their users at this minimum frequency.
While it is clear that the majority of POTWs have the capability to collect and analyze
samples and to perform facility inspections, the successful completion of these tasks has
been limited by the availability of resources. Chapter 7 of this report more completely
evaluates the overall effectiveness of POTW compliance monitoring and enforcement
activities.
5.6 EVALUATION OF POTW CAPABILITY TO DEVELOP AND IMPLEMENT LOCAL
LIMITS . ' .. •
The capability to achieve technical objectives and the POTW's capability to perform the
technical tasks required to develop and implement local limits will be considered separately in
Subsection 5.6.2. This evaluation will address each of the objectives and tasks identified in
Figure 5-2 and Table 5-6 (Section 5.4). To identify appropriate objectives, Subsection 5.6.1
considers the local limits process with respect to its statutory, regulatory, and programmatic
history.
5.6.1 History of the Development and Implementation of Local Limits
5.6.1.1 Statutory History
The statutory basis for the National Pretreatment Program-is the Federal Water
Pollution Control Act of 1972. Section 307(b) requires EPA to develop pretreatment
standards designed to prevent the discharge to POTWs of pollutants "which interfere with,
pass through, or are otherwise incompatible with such works." Section 402 of the Clean
Water Act Amendments of 1977 included additional pretreatment requirements. Specifically,
POTWs became responsible for development and implementation of local pretreatment
programs and for ensuring compliance with pretreatment standards. Such standards consist
of categorical standards, prohibited discharge standards, and local limits (see Section 5.1).
"* ' ' • , • • .- i . --•."-'. ' - . . -
5.6.1.2 Regulatory and Programmatic History
EPA first promulgated regulations that addressed industrial discharges to POTWs on
November 8, 1973 (38 FR 30983, 40 CFR Part 128), including provisions that prohibited
certain discharges of wastewater by nondomestic users of POTWs. No specific
requirements, however, were included that addressed development of local discharge
standards.
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Following the passage of the Clean Water Act Amendments in 1977, on June 26, 1978
(43 FR 27736), EPA promulgated the General PretreatmentRegulations to implement the
new pretreatment-related requirements of Section 402 of the Clean Water Act. These
regulations, codified as 40 CFR Part 403, incorporated the prohibitions of 45 CM Part 128,
defined the term interference, and established a requirement for POTWs to develop and
implement local pretreatment programs to enforce these prohibitions. Subsection 5.1.1
presents in greater detail the general and specific prohibitions of the General Pretreatment
Regulations.
Section 403.5(c) of the General Pretreatment Regulations of 1978 required POTWs that
were establishing pretreatment programs to "develop and enforce specific limits for
discharges of pollutants" identified in the general and specific prohibitions. Section 403.5(c)
of the regulations also required POTWs that were experiencing NPDES permit violations to
develop limits to prevent recurrence of the violations, whether or not the POTW was required
to have a pretreatment program. These specific limits are more commonly referred to as local
limits.
On January 28, 1981, EPA promulgated revisions to the General Pretreatment
Regulations that added the definition of pass through and required POTWs to provide public
notice of the development of local limits.
In October 1983, EPA issued the Guidance Manual for POTW Pretreatment Program
Development (EPA, 1983). Chapter 4 and Appendix L of this guidance manual included a
methodology for determining local discharge limitations to be followed as part of the POTW
program development process. The local limit evaluation was intended to be part of the
pretreatment program submission for review by the approval authority. In 1984, the Agency
issued the first of a series of computer programs/moclelscalled PRELIM (PREtreatment
LIMits) to assist POTWs in the calculation of the local discharge limits. PRELIM was
intended to facilitate the development of POTW pretreatment programs and numeric effluent
limitations consistent with the 1983 guidance manual. The July 1990 amendments to the
NPDES permitting regulations require POTWs to submit with their NPDES permit renewal
applications a written technical evaluation of the need for local limits (40 CFR 122.21[j][4]).
The National Association of Metal Finishers (NAMF) brought suit against EPA for the
1981 revisions to the General Pretreatment Regulations. In NAMF v. EPA. 719 F. 2d 624
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(3rd Cir. 1983), the definitions of "interference" and "pass through" were successfully
challenged, along with other provisions of the regulations.
To address concerns by approval authorities and to evaluate the National Pretreatment
Program during this period of regulatory maturation, EPA established the Pretreatment
Implementation Review Task Force (PIRT). Chapter 1 provides an overview of the focus of
the task force and the major findings included in the January 1985 Pretreatment
Implementation Review Task Force: Final Report to the Administrator (EPA, 1985b). The
task force determined that POTWs "do not understand the relationship between categorical
standards and local limits or even how to develop local limits." The report recommended that
EPA define clearly the specific requirements for local limits development and provide
guidance that would enable POTWs to understand and develop these limits.
EPA built upon the existing guidance for development of local limits to implement the
PIRT findings. On August 5, 1985, the Office of Water Enforcement and Permits issued a
memorandum clarifying the expectations for POTW local limit development and identifying the
minimum number of pollutants for which the local limits evaluation must be conducted. In
addition, PRELIM was upgraded and released as Version 3.0 in January 1987, accompanied
by the PRELIM USERS GUIDE: Documentation for the EPA Computer Program/Model for
Developing Local Limits for Industrial Pretreatment Programs at Publicly Owned Treatment
Works (EPA, 1987b). At the same time, the Agency began developing more extensive
guidance on the development of local limits. EPA subsequently issued the Guidance Manual
oh the Development and Implementation of Local Discharge Limitations Under the
Pretreatment Program (EPA, 1987a). This manual contained the second local limits policy
memorandum. A March 22, 1988, memorandum from the Office of Water Enforcement and
Permits to users of the guidance manual states that "each POTW must assess all of its
industrial discharges and employ sound technical procedures to develop defensible local limits
which will assure that the POTW, its personnel, and the environment are adequately
protected." The memorandum also expanded the list of pollutants for which the POTW
should conduct the analysis. ,
On January 14, 1987, the Agency promulgated revised definitions for interference and
pass through (52 PR 1600). The new definitions provide a regulatory basis for determining
the interference and pass through of pollutants. Additional regulatory revisions that affected
local limits development were promulgated on October 17, 1988 (53 FR 40610). These
revisions resulted from the PIRT report and required POTWs seeking approval of their
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pretreatment programs to develop technically based local limits, or to demonstrate that these
limits are not necessary, prior to program approval. In addition, the preamble of the revisions
explains that POTWs with approved programs that have not performed a technical evaluation
of the need for local limits will have their NPDES permits modified "as soon as feasible" to
include a requirement to do so.
In accordance with the DSS, EPA proposed regulatory revisions that would further
strengthen the regulatory requirements for POTW pretreatment programs and development of
.;J jf' , • ' - ,, „ • i • "• • ' ! <, i •; i!. • ' ; 'i „ i • • '"••: ]-M! ,ij" !i; fflVP !» ;•': ' 'i • Mff» of,. .i?; - \i .w."' • L •"" 111!" i; i» ;o ^ «' •,: i v ^ h >"•• ^t •• • * •» •, • .un * i,n,;, > i w '•.»wr
local limits. These revisions to 40 CFR Parts 403 and 122 (the General Pretreatment and
• ,;in . • " • ,',»', , • ,' ' i' , i ni, ,i ,I:IIIIIII!,,M • |,!i'''iiiiiiiiiij|iii!i'. ii" ii,i1 i >,', '• • ', "i1,N ' : h i "" iii',','' M ,'i 'i ' ,,,•',imiii i ,i,',i",,
NPDES Regulations) (55 FR 30082) were promulgated on July 24, 1990. The rule requires
all POTWs with approved pretreatment programs to evaluate in writing the need to update
their local limits as part of their NPDES permit application (i.e., every 5 years) unless the
permit issuing authority requires more frequent evaluation in the permit. By adding specific
prohibitions to the General Pretreatment Regulations, the rule also requires that local limits
be established to ensure that nondomestic users meet the new specific prohibitions.
Figure 5-7 summarizes the major statutory, regulatory, programmatic, and court
developments relating to local limits.
v . • , - •• • • . i, ,. : .:.'•.- ;.:••'.• "i! ; vti :„,', it i"'.'.""'-,:,i-".';;'si, :,'.:*",:; is; \ .'•••! ".'.•,« vr-\'t;:
5.6.2 Capability to Develop Local Limits
As explained in Section 5.4, the assessment of POTW capability is based on two
elements: availability of technical objectives and capability to perform required technical
tasks. With respect to local limits, the principal technical objectives are to develop standards
for all pollutants of concern necessary to meet the POTW's NPDES permit limits, water
quality standards, sludge use, and disposal requirements; protect the treatment plant and its
collection system; and ensure that the health of POTW workers and the public is not
jeopardized by exposure to these pollutants. EPA has identified the principal POTW tasks
as collecting data, identifying pollutants of concern, calculating revised standards, and
applying these standards.
. • ' ,•;»;• '" -',; ;,'•. ''•'.,•'.•. « i
5.6.2.1 Capability to Achieve Technical Objectives
The capability to achieve the technical objectives identified previously depends on two
key elements:
i1!!1!1!,:!'1;1!,!'1*! «'!!l,!"i
Does the local limits development process ensure that POTWs identify and regulate
all pollutants of concern?
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__ (A
$
I
3
2
o
Wl
-------
I ' I
• Are the environmental and technical criteria upon which local limits are based in place
for each pollutant of concern and are they sufficiently protective of the environment
and public health?
If these elements are covered sufficiently by the development process mandated by
regulation, POTWs will need only meet the regulatory minimums to ensure that the technical -
objectives are achieved.
Identification and Regulation of Pollutants
To evaluate fully potential pollutants of concern, POTWs must review industrial,
domestic, and POTW sampling data and evaluate the results with respect to meeting the
second technical objective, listed above. Because POTWs have historically been concerned
with conventional pollutant control, few toxic pollutant data are often available for their use.
Even with the absence of these data, POTWs have made substantial progress with regard to
adopting limits. Table 5-9 identifies the types of pollutants currently regulated by 200
POTWs for which EPA analyzed audit results from between 1985 and 1990. While it only
represents those POTWs with limits, it clearly indicates that the overall scope and coverage
of toxic pollutant control through local limits is quite extensive, particularly for metals. As
discussed in Subsection 5.3.1.2, POTWs' NPDES permits generally limit few toxics; thus,
this relatively high number of toxics controlled by local limits indicated in Table 5-9
demonstrates the understanding of POTWs concerning the need for toxics controls at the
local level.
A number of factors affect the capability of POTWs to identify and regulate pollutants of
concern. As discussed in Subsection 5.2.2, there are no regulatory minimums regarding
POTW data collection for this purpose. Agency guidance recommends at least 6 months of
monthly POTW influent and effluent data, or 5 consecutive days of monitoring designed
specifically for local limits development. While some States, EPA Regions, and POTWs
:,;"' ' ' .'' • ' ': > , . :' :..'• I ' I i1 I'M i I n IN i i in 11
have interpreted this to mean priority pollutant scans, many POTWs have collected data only
for the pollutants recommended by EPA guidance (i.e., arsenic, cadmium, chromium, copper,
cyanide, lead, mercury, nickel, silver, and zinc). While Agency review of POTW pollutant
":, •• . • • •:, i;,,,-i; |r. •. •;•:'. •',',>;: ,--,-n . i; r./M '•„ .•.«" 'A,, n, ..,•••'<"" y
loadings has revealed significant concentrations of pollutants beyond these 10 (see Chapter
3), there are no regulatory requirements that specify which pollutants must be monitored.
Additionally, those POTWs performing pollutant scans rarely increase the scope of these
scans beyond the 126 priority pollutants.
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Table 5-9. Pollutants for Which Selected PQTWs Have Established Local Limits*
Pollutant
Copper
Cadmium
Lead
Nickel
Zinc
Chromium (total)
Cyanide
Mercury
Arsenic
Silver
Phenols
Oil and Grease
Selenium
Iron
PH
Barium
Chromium (hexavalent)
Boron
Manganese
Temp
Chlorinated Hydrocarbons
Fluoride
Sulfide
Chlorides
Sulphates (SC«4)
Beryllium
TTO
Ammonia
COD
Total Metals
Tin
Cobalt
Antimony
Sodium
Phosphorous
Chromium (trivalent)
Range of Concentration
Min (mg/1)
0.03
0.0019
0.02
0.05
0.05
0.05
0
0
0
0.03
0
2
0.01
0.3
5
1
0
0.1
0.05
47
0
1
0.1
200
20
0.022
. 0.01
, 25
400
5
0
0.15
0.02
90
2
0.5
Max (mg/1)
15
15
•' 5
18.1
30
73
10
3.17
6
30
100
350
11.1
100
12
183
3.5
2.5
10
150
3.5
224
100
3000
1000
0.8
5
1215
1000
10.5
4
9.3
260
4000
15
3.5
Number of
POTWs with
Limit
195
186
186
184
184
169
162
151
145
145
99
74
69
68
59
53
50
50
48
44
38
34
32
30
27
21
18
17
17
16
14
13
13
12
11
11
Percentage of 200
POTWs with
Local Limits
97.5
93
93
92
92
84.5
81
75.5
72.5
72.5
49.5
37
34.5
34
29.5
26.5
25
25
24
,22
19:
171
16
15
13.5
10.5 i
9
8.5
' 8.5
8
, 7
6.5
6.5
6
5.5
5.5
*Local limits were examined for 200 pretreatment control authorities known to have local
limits for one or more pollutants.
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Table 5-9. Pollutants for Which Selected POTWs Have Established Local Limits*
(continued)
Pollutant
Oil & Grease (petroleum)
Aluminum
TDS
PCB
Methylene Chloride
Thallium
Phosphates
Calcium
Vinyl Chloride
MBAS
TOG
Tetrachloroethylene
Nitrogen
Toluene
Hardness (total)
Endrin
Sulfite
Trichloroethylene
Formaldehydes
Chloroform
Bromine; Chlorine, Iodine
Pentachlorophenol
Bis(2-ethylhexyl) Phthalate
Benzene
Toxaphene
Molybdenum
Magnesium
Cresols
Methoxychlor
Ethyl Benzene
Benzidine
Vanadium
Lindane
Heptachlor
Carbon Tetrachloride
Range of Concentration
Min (mg/1)
•
100
2
515
0.000000012
0.1
0.2
1
50
0.01
10
10
0
22
0.025
35
0.001
2
0
5
5.81
1
0.01
0.1
25
0.03
0.1
10
1
0.04
0.025
0.001
0.1
0.01
0.001
8.5
Max (mg/1)
100
500
1000
0.18
30
30
45
8000
0.5
150
200
28.54
60
500
320
0.1
2
. 0.5
5
45
10
0.1
1.03
30
0.35
50.3
50
1
0.3
26.25
0.001
12.4
0.02
0.002
50
Number of
POTWs with
Limit
10
10
9
9
9
7
7
6
6
5
5
5
5
5
5
4
* 4
4
4
4
4
4
3
3
3
3
3
2
2
2
2
2
2
2
2
Percentage of 200
POTWs with
Local Limits
5
5
4.5
4.5
4.5
3.5
3.5
3
3
2.5
2.5
2.5
' 2.5
2.5
2.5
2
2
2
2
2
2
2
1.5
1.5
1.5
1.5
1.5
1
1
1
1
1
1
1
1
*Local limits were examined for 200 pretreatment control authorities known to have local
limits for one or more pollutants.
Note: Local limits for 72 additional toxic pollutants have been established by no more than
onePOTW.
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Generally, the sampling performed by POTWs for local limits development conforms to
Agency guidance or other approval authority requirements. These minimum frequencies are
less rigorous than is required for a POTW application for authority to grant removal credits
(i.e., 5 or 6 samples versus 12). In addition, as mentioned above* the limited scope of
pollutants for which sampling is routinely performed reduces the POTWs' ability to identify
all pollutants of concern.
Adequacy of Environmental amd Technical Criteria
Environmental and technical criteria are the bases for the establishment of local limits;
they establish the total amounts of pollutants that the POTW can accept without inhibiting its
treatment processes or discharge without adversely affecting the environment or public
health. To establish local limits, POTWs generally rely on NPDES permit limits, applicable
water quality and sludge disposal standards, and unit process inhibition criteria. In addition,
a few POTWs have considered collection system criteria and worker health and safety while
developing limits. ,
The discharge of pollutants from POTWs to the environment through effluent and sludge
is regulated under State and Federal discharge permitting program, particularly, the NPDES
permitting program. As discussed in Section 5.3, the NPDES program principally regulates
the discharge of conventional pollutants, with only about 21 percent of those permits issued
to pretreatment POTWs containing one or more toxic limits. In addition, NPDES permits are
required to contain limitations on the disposal of sludge. The Agency's comprehensive sludge
regulations (40 CFR Part 503) are currently being developed. Until these regulations are
final, few regulatory controls concern sludge disposal (see Section 5.3). The number of
pollutants regulated by local limits should increase with the presence of more extensive limits
in POTW permits.
. As explained in Subsection 5.3.4, to protect unit treatment processes from inhibition or
upset due to toxic pollutants, POTWs can establish limits based on known pollutant
concentrations that cause these adverse effects. In general, inhibition levels are only
available in literature for activated sludge processes and anaerobic digestion, and only for the
more common toxic pollutants. The appropriateness of literature values has been contested
by POTWs that receive pollutant loadings that are significantly above the supposed inhibition
thresholds;—and to no ill effect. Where treatment plant performance is not indicative of
process inhibition at the pollutant concentrations indicated by existing inhibition criteria, this
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may be explained by the limited coverage of current literature data and site-specific factors,
such as process acclimation or pollutant interactions that reduce the toxicity of the pollutant.
To ensure that POTW workers are adequately protected from exposure to toxic
pollutants, POTWs should also use worker health and safety criteria for establishing local
limits. Currently, few POTWs have developed numeric worker health and safety criteria,
primarily because the methodology for establishing these limits for volatile organic
compounds has not been developed fully. As described in Subsection 5.2.2, many POTWs
require industrial users to adhere to wastewater management practices that protect POTW
workers. Such controls, however, are generally not reflected in local limits submittals or the
200-POTW local limits data base analyzed in Table 5-9. "They 'are not reflected in the Local
Limits Data Base either, which contains detailed information on local limits development of
57 POTWs. ' ' _ ' , " •' ' , '"'- ' '" "'" ' ' '"" '"'" ' ""'
5.6.2.2 Capability to Perform Required technical Tasks
The evaluation of POTW capability to perform required tasks is keyed to four
development and implementation technical tasks, as discussed in Subsection 5.4.1:
"....„.'...'., t ,',.••,
• Collection of requisite data
• Determination of pollutants of concern
• Calculation of revised standards
• Application of revised standards.
To assist POTWs in performing these tasks, EPA developed the Local Limits Guidance, as
well as the PRELIM computer program and Users' Guide, and provided local limits training
throughout the United States. Each of the specific technical tasks identified in this section is
covered by these guidance materials and training.
EPA notes that a POTW's performance on these tasks may be less closely linked to its
capability than to its relative willingness or interest, which will affect how it allocates its
limited resources. Although willingness to achieve an intended goal relates to whether a
task will be completed successfully, it is not measurable and EPA did not address it in this
evaluation.
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Collection of Requisite Data
Characterize Discharges to the Collection System
To characterize discharges to the collection system, POTWs must identify all sources of
pollutants and characterize the nature of the discharges. According to PASS, 79 percent of
POTWs have successfully identified all industries that discharge to the sewer system and 71
percent have identified their categorical industries correctly. In addition, 65 percent of
POTWs were found to have sampled their significant industrial users at least annually.
Observations from the Local Limits Data Base provide insights into POTW efforts to
characterize contributions from nonindustrial sources. Twenty-seven of the 57 POTWs used
actual sampling data to characterize the pollutant contribution from nonindustrial (i.e.,
domestic and commercial) sources. Additionally, 6 of the 57 POTWs used default literature
values for pollutant loadings from domestic sewage. Data were not available to determine
the sources of domestic contribution information from the other POTWs in the data base.
The data presented above indicate that a majority of POTWs are capable of identifying
pollutant sources and characterizing the nature of the discharges. This, however, must be
viewed in conjunction with the findings in Chapter 3 of this report, which indicate that
significant pollutant loadings may occur from sources other than industrial users, and that the
number of pollutants being discharged to sewers significantly exceeds the 126 priority
pollutants.
Characterize Pollutant Removals Achieved by the PQTW
To identify pollutant removals achieved at their wastewater treatment plants, POTWs
must design and carry out sampling programs to characterize their plants' influent (raw
sewage), effluent (treated wastewater discharge), and sewage sludge. Indicators of this
capability in the Local Limits Data Base show that POTWs used data from an average of 13
influent, 11 effluent, and 7 sludge samples to support removals calculations. Forty-five of the
57 POTWs in the data base analyzed samples for at least 10 pollutants, while only 2 of 57
conducted complete priority pollutant scans.
j
These data indicate that the vast majority of POTWs are generally capable of sampling
and analyzing treatment plant wastestreams in order to calculate pollutant removals. Current
Agency guidance (local limits guidance manual) suggests that POTWs undertake at least 5
consecutive days of sampling of treatment plant wastestreams for both metals and organics.
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" ;'.;
-------
Data from the GAO (1989) report indicate that of a total of 393 POTWs, 354 evaluated
an average of 15.5 pollutants and adopted local limits for 14, and 15 POTWs evaluated the
need for control on an average of 14 pollutants and adopted no local limits (the remaining 24
POTWs were not included in the evaluation). Of the 354 POTWs with limits, only 109 had
limits for toxic pollutants in their NPDES permits, suggesting that local limits were derived
from other criteria related to plant protection or sludge disposal or were developed using an
approach other than EPA's MAHL technique.
Identification of Applicable Plant and Worker Protection Criteria
Plant protection. EPA's Local Limits Data Base indicates that 43 of the 57 POTWs
used literature values for process inhibition. This suggests that POTWs are capable of
identifying and using available literature values (as opposed to site-specific concentrations)
for threshold process inhibition pollutant levels. However, EPA notes that in many cases,
the actual pollutant concentration entering the various POTW treatment processes exceeds
the literature inhibition concentrations with no apparent negative effect. This may be due to
system acclimation to higher pollutant levels or to other POTW-specific conditions not
represented in the development of the literature values. In these instances, it is appropriate
for POTWs to substitute the actual measured loadings in lieu of the literature values if there
is clear evidence that no negative process effects will occur.
Worker health and safety. Only 3 of the 57 POTWs in the Local Limits Data Base
considered worker health and safety issues when developing the list of potential pollutants of
concern. While this appears quite low, EPA is aware that many POTWs require contributing
industries to adhere to wastewater management practices that protect POTW workers. Such
controls are not reflected in local limits submittals and therefore would not be included in the
Local Limits Data Base. This is likely to change given EPA's commitment to increasing
POTW awareness of worker health and safety issues as part of its implementation of the
recent amendments to the General Pretreatment Regulations (particularly the specific
prohibitions addressing toxic gases).
Calculation of Discharge Standards ,
The calculation of local limits generally requires two steps:
• Calculation of allowable pollutant headworks loadings that ensure that the POTW
will meet the identified NPDES limits, sludge use and disposal standards, and
POTW protection criteria
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Calculation of discharge standards that allocate the allowable pollutant loadings to
industrial users.
As shown in Figure 5-1 (Subsection 5.2.2) and Appendix C-l, the mathematics
involved in calculating local limits is straightforward, involving only addition, subtraction,
multiplication, and division. The only complications in this effort arise from the relatively
large amount of required data.
To assist POTWs in performing the calculations necessary to develop local limits, EPA
has developed the PRELIM computer program. To date, EPA has provided POTWs with
1,266 copies of the PRELIM software and users' manual. In "'aiddition^ 31 of me 57 POTWs in
the Local Limits Data Base are known to have used PR^GiMJn,.their calculations. PASS
indicates that 34 percent of POTWs have calculated technically based local limits. Of those
POTWs that have not calculated technically based limits, the reasons generally relate to
issues other than capability (see discussion in Section 5.7). EPA is confident that POTWs
are receiving the necessary, support and have the capability to perform the calculations
necessary to develop local limits.
Incorporation of Discharge Standards in Control Mechanisms
The POTW must incorporate local limits into its legal ordinance or control mechanism,
so that they are enforceable at the local level, and develop a program of compliance
monitoring and enforcement to ensure that the standards are being implemented. In
particular, the POTW should apply these standards through its inSustnal user permit system
or other approved control mechanism. Both local limits and categorical discharge standards
should be reflected in the industrial user's control mechanism and should subject the user to
the POTWs compliance/enforcement program.
Subsection 5.2.2.1 notes the difficulties encountered by many POTWs with respect to
the point of application of local limits versus categorical standards (i.e., end-of-pipe versus
end-of-process) and the difficulty in comparing these standards directly. Because it is
difficult to compare these limits directly, including the most stringent limit in the discharge
permit is often difficult. PASS revealed that 27 percent of POTWs have not performed this
comparison successfully. Chapter 7, Effectiveness of the National Pretreatment Program,
discusses this issue in greater detail.
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According to PASS, 61 percent of POTWs have incorporated applicable discharge
standards (local limits and/or categorical standards) into control mechanisms. Several
factors may .explain why this number is not higher. Many POTWs are still in the process of
developing local limits. Other POTWs are reluctant to revise their ordinance-based systems
or address individual discharges through permit systems because of the resource demands vof
a permit system arid sometimes because of a perceived lack of the need for local limits.
POTWs may go through the exercise of developing discharge standards but regard
implementation of local limits as superfluous as long as NPDES limits and sludge standards
are being met Except for the lack of resources, these reasons do not indicate that POTWs
are not capable of incorporating the limits into control mechanisms, however.
5.7 STATUS OF PQTW EFFORTS TO DEVELOP REMOVAL CREDITS AND LOCAL
LIMITS
This-section evaluates the current status of POTW efforts to develop removal credits
and local limits. Information on the efforts of three case study POTWs follows this
evaluation.
5.7.1 Removal Credit Status
The current status of removal credits is clear (as described previously): the program
has been suspended pending promulgation of national sludge standards. Once national
sludge standards are promulgated (promulgation of the initial set of standards is expected
during the latter part of 1991), the principal obstacle blocking removal credits will be removed,
and the Agency will reevaluate the adequacy of the regulations.
The Agency has continued to improve its knowledge concerning the fate of pollutants
introduced to POTWs. As standards to protect all environmental media to which pollutants
may partition are promulgated and updated, EPA may reassess the appropriateness of the
existing removal credit regulation.
5.7.2 Status of Local Limits
POTWs are currently implementing local limits derived in a number of ways. Table 5-10
illustrates the general types of local limits that have been adopted and implemented by
POTWs. POTWs have allocated the allowable industrial loadings to industrial users using
methods such as those identified in Section 5.2.2.1. The most frequently employed method is
allocation of a uniform concentration limit (e.g., allocating 2 mg/1 of copper for all industrial
users). POTWs surveyed by GAO were implementing local limits for an average of 14 toxic
pollutants (they had evaluated the need for limits for even more pollutants, an average of
5-71
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Table 5-10. Types of Local Limits Being Implemented by POTWs
i ill
Type of Local Limit
Number of POTWs1
Percent of POTWs1
Limits in Place
No Numeric Limits
459
54
89.5
10.5
Limits That Are Technically
Based2
Technical Evaluation
Performed, but Preexisting
Limits Retained
Limits Based on Categorical
Standards
Limits With No Known
Technical Basis
173
26
35
225
33.7
5.1
6.8
43.9
1. Based on atotalof 513 pretreatment programs audited from 1985 to 1990.
2. Technically based means having conducted a headworks loading analysis, as suggested in
EPA's Local Limits Guidance (1987a).
Source: PASS (1990).
5-72
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15.5). Of 513 pretreatment programs for which detailed information on local limits was
available from pretreatment program audits, 459 (nearly 90 percent) had adopted numeric
local limits for one or more toxic pollutants. One hundred and seventy-three POTWs
(approximately one-third) had adopted technically based local limits. Twenty-six POTWs
(5.1 percent) had performed a technical evaluation but retained their existing limits.
Generally, POTWs retained their existing limits when the evaluation showed that technically
based limits would be less stringent. Another 35 POTWs (6.8 percent) had adopted national
categorical standards (usually electroplating or metal finishing standards) as loc.al limits
applicable to all industries. Finally, 225 POTWs (43.9 percent) had local limits with no
known technical basis; in many of these cases, POTWs simply adopted a neighboring city's
limits or limits described in the literature. As shown in Table 5-9 (Section 5.6), POTWs
regulate a wide range of pollutants with local limits. While no projections to the universe of
pretreatment POTWs can be drawn from this table, these data show that, in general, POTWs
have been responsive to EPA guidance. Over 70 percent of the 200 POTWs had adopted
local limits for the 10 pollutants EPA's 1987 guidance recommended for consideration.
Significantly fewer POTWs regulate other pollutants, although many POTWs do regulate one
or more pollutants not included in EPA's guidance. Overall, nearly all priority pollutants, as
well as a number of nonconventional pollutants, are regulated by one or more POTWs. It
should be noted that not all of the local limits for these 200 POTWs were technically based
(i.e., based on EPA's 1987 Local Limits Guidance). The types of limits developed include all
of those described in Table 5-10. Thus, even though the range of pollutants regulated by
POTWs is impressive, many of these POTWs (and their respective approval authorities)
may not have a clear idea of whether they are regulating the appropriate pollutants or
whether their limits are set at an appropriate level.
Of particular note is that POTWs regulate many more pollutants than are regulated in
the POTWs' NPDES permits. According to EPA's permit compliance system (PCS), 32
percent of NPDES permits for pretreatment POTWs issued in 1989 contained limits for one or
more toxic pollutants. •-.'..
As noted, some POTWs have determined that local limits based on applicable
environmental criteria and on protection of the treatment plant would be less stringent than
their current limits, which may have been taken from the literature or from other sources. In
some cases, for example, local limits based on NPDES permit limits and environmental
standards and criteria might allow significant increases in pollutant discharges from indirect
dischargers without affecting designated uses or violating these applicable limits and
5-73
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standards. Some POTWs—those with industries meeting the more stringent local limits--
will prefer to continue implementing preexisting limits. However, Federal and many State
regulations require only that local limits ensure compliance with the General and Specific
r i ' • , • m. , i •,,"'. »i • • ,i in", ' ,11 • "• i f . f inn, ,,iiii.'.i nl ,:,"!",„' : . .IF ,1,1,ii,n, if, u i,,!', in ,„ i,,i"• „', n ,,i,,ii „„ ,K,'| i „„,'", • , mi
Discharge Prohibitions (which, in turn, are based on compliance with NPDES and sludge
'.' ':, •. I ' ' ' ' , : i' '. , '" ' " ii i i
requirements).
P 'A
5.7.3 . Case Studies
: 'V ', • • '" . ' • • ,'' ..• " . • .Si ; . til i| "i i|
To provide illustrative information with respect to POTW revision of pretreatment
standards, case studies were developed for three pretreatment POTWs: Thomasville, North
Carolina; Hampton Roads Sanitation District (HRSD), Virginia; and Pocatello, Idaho. For
each of these POTWs, data regarding the types of pollutants monitored and regulated were
collected and are presented in Tables 5-11, 5-12, and 5-13 and in Figure 5-8. None of the
case study POTWs had applied for or had been granted removal credits approval; thus, the
findings presented here concern only local limits.
Table 5-11 presents the case study findings regarding the numbers of toxic pollutants
regulated by these POTWs' local limits in relation to the numbers of toxic pollutants detected
at the POTWs and regulated by applicable standards and criteria. Figure 5-8 charts the
results. The data indicate that for these POTWs the number of pollutants regulated by local
limits is similar to the number of pollutants detected in the POTWs' influent, effluent, and
sludge. However, in each case, the number of toxic pollutants regulated by the POTWs'
NPDES permits and sludge disposal requirements is significantly lower, generally at zero.
While this pattern cannot be used to predict the situation at other POTWs, it does agree with
the evaluation of Section 5.6: namely, that the standards and criteria necessary to drive the
',:! •• , .' . <• . ., /.'•• ;,T:; :; ;" ':•-;: -'"^W- 'JK ""Ka'S,:,"- ^"r.'fi, ,^?r, ..\*:. '„;;.-; : ',•:,:•'.
local limits development process are not generally in place.
Table 5-12 presents case study data with respect to the frequency of sampling and
types of toxic pollutants for which sampling was performed at these POTWs. In general, the
sampling frequencies reported did not follow any patterns across these POTWs; however, the
types of pollutants for which sampling was performed were more consistent. At each of the
POTWs, metal parameters and cyanide were of primary concern. This is also in agreement
with other chapter findings.
Table 5-13 presents the results of the case studies with respect to the number of
samples utilized in the development of local limits at each PbTW. Again, there was no clear
5-74
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5-75
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Table 5-12. Sampling Frequency by Case Study POTWs, 1989
City/POTW
Thomasvme, NC
HRSD, VA
Pocatello, ID
Number of Samples
Influent
80
12
1
6
Effluent
85
.12
1
6
Sludge
4
12
1
2
Pollutants
Analyzed For
Six to seven
metals and
cyanide (CN)
Six metals
Priority pollutant
scan
i
Nine metals,
CN, and fluoride
Table 5-13. Number of Samples Used by Case Study POTWs
to Develop Local Limit
aty/POTW
Thomasville, NC
HRSD, VA
Pocatello, ID
Number of Samples Used
Influent
17*
Not
Applicable**
6
Effluent
17*
6
Sludge
2*
-
2
In-Plant
0
0
Other
0
0
*For metals only.
**HRSD did hot develop technically based local limits as defined in the current EPA.
Guidance. -
5-76
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140
Thomasviile, NC HRSD, VA Pocatello, ID
Monitored for (influent, effluent, and/or sludge)
Detected (influent, effluent, and/or sludge)
Regulated by local limit
Regulated by NPDES permit
Regulated by sludge permit
Figure 5-8. Numbers of Pollutants Monitored, Detected, and
Regulated at Case'Study POTWs, 1989
5-77
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pattern across these POTWs; however, at two of the three POTWs the minimum sampling
recommended by EPA was performed.
5.8 FINDINGS
This section summarizes the findings of the evaluation of POTW capability to revise
pretreatment standards. The findings are divided into two sections, local limits and removal
credits. As an introduction, each of these sections briefly discusses issues affecting these
program elements. .
5.8.1 Local Limit Findings
The development of technically based local limits to control the discharge of toxic
pollutants from POTWs has been constrained because technical objectives cannot currently
be achieved by most POTWs.
i ' ' ' ,„„,,,,, , ^i, ,n, , ',,',,,„''
• Few POTW NPDES permits contain limits for toxic pollutants. According to PCS,
only 32 percent of the NPDES permits for pretreatment POTWs issued in 1989
contained limits for one or more toxic pollutants. This is, in part, due to the fact that
many States have not yet developed water quality standards for all their receiving
waters.
• Numeric criteria for sludge use and disposal practices have not been promulgated by
EPA. Most States do not have comprehensive sludge standards.
• The Clean Air Act Amendments of 1990 do not require that emission standards for
toxic pollutants applicable to POTWs be promulgated until 1995.
• Literature data to predict pollutant concentrations that may result in unit process
inhibition are available for only a few pollutants, are based on a limited sample size,
and may not characterize site-specific conditions accurately.
POTWs appear to be capable of performing the technical tasks to develop numeric local
limits. The number of pollutants limited by POTWs often exceeds the number limited by the
, 'i i, ,;, ' i ' , • ,i „ " , , i |. ,r: i ' . ,i,r i'i"i'
POTW's applicable environmental criteria, including NPDES permit limits and sludge
requirements. POTWs surveyed by the General Accounting Office were found to impose
local limits for an average of 14 toxic pollutants.
"• *
• POTWs have failed to collect the necessary influent, effluent, and sludge monitoring
data to calculate site-specific treatment plant removals and to establish allowable
headworks loadings based upon these removals.
• The sampling and analysis involves a commitment of resources that many POTWs
are unwilling to devote to developing local limits, particularly when they are not
5-78
1111 | ",'> i.VIT! '• IM!"' '.. 'I'/hli W!
-------
required to do so because of the absence of limits for toxic pollutants in their NPDES
permits. '•.'..'
• Additional factors can affect the development arid implementation of local limits.
• While the methodology exists for developing local limits for conservative pollutants
(e.g., metals), there are no similar methods for.establishing limits for organic and
reactive pollutants. POTWs that have adopted numerical limits for these types of
pollutants have generally used a best professional judgment approach.
r The point for determining compliance for local limits can be different from that for
determining compliance with categorical standards. .This has created difficulty for
some POTWs.
• The uniform concentration method of allocating the POTW treatment plant allowable
industrial loading is the most frequently used because it results in the same limit for
all industrial users. Some POTWs have alternatively used a market-based approach
that allows industrial users to negotiate allocations among themselves.
POTWs that have not developed or adopted local limits tend to believe that local limits
are not necessary because:
• They may have no evidence that pass through or interference is occurring, partly
because of the lack of toxic controls in the NPDES permit or toxic controls applicable
to sludge.
• They may believe that categorical standards are adequate to protect their treatment
system and the environment. '
5.5.2 Removal Credit Findings
Section 307(b)(l) establishes the technical objectives of the removal credits program.
Removal credits cannot be made available under the current regulations until those objectives
are met.
• Because most POTW NPBES permits do not contain numeric limitations based on
water quality standards, in the past removal credits were generally granted without
consideration of their water quality impact.
• In any future revision .of the removal credits regulation, the definition of "consistent
\removal" will remain an, issue. While both BAT (direct discharge) and PSES
(indirect discharge) standards are set such that the applicable technology can meet
the limit 99 percent of the time for daily maximum and monthly average limitations, a
POTW's demonstration of "consistent" removal for purposes of removal credits does
not require the same degree of confidence. Since a POTW pursuing removal credits
for its industrial users need only show removal that it can achieve 75 percent of the
time, its treatment combined with its industrial users treatment may be less than that
provided by direct dischargers.
5-79
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Removal credits cannot be made available until EPA develops standards for the
sludge use and disposal options employed by the POTW applying for removal credit
authority.
'!', "' :" ' '•,••' •','*• ',- •••»'. ,i1. .•:,'•• "; J P11,': A,'''•,•;; "B? !••!'•'SK'i W J,.• f'«•'i;'*,•:'• M*'^i(i-i MS >,\Xt'---yt:.:VNW!ViaHt,iir*
Current regulations do not specifically address the removal of pollutants during
treatment through volatilization to the atmosphere. If this type of removal is to be
prohibited, regulations will need to be revised. •
V ' • ,i : •. , ' ', . "i: s: -, i," •. j ;' i1::'1.',." v,;, "'•:: .ii'*M4^/t,WI3liiPW.>..W1'W!L'1:iOTJ biiifei" ''i!,* 111"'l;i n,;1!!-;, if'-f'Ji'M'Hi'iiil1"1,1!
The current regulation decreases the removal credit that can be made available by
POTWs whose influent bypasses treatment because of combined sewer overflows.
However, CSOs may result in the effluent from an indirect discharger being treated
less consistently than a direct discharger's effluent if the indirect discharger is relying
on a removal credit to comply with categorical standards.
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REFERENCES
U.S. Environmental Protection Agency. 1990. Status Report: State of Compliance With
, CWA, Section 303(c)(2)(B) as of February 4, 1990. Washington, DC: Office of Water
Regulations and Standards.
U.S. EPA. 1989. Sewage Sludge Interim Permitting Strategy. Washington, DC: Office of
Water and Office of Water Enforcement and Permits.
U.S. EPA. 1987a. Guidance Manual on the Development and Implementation of Local
Discharge Limitations Under the Pretreatment Program. Washington, DC: Office of
Water Enforcement and Permits. 530-SW-86-004.
U.S. EPA. 1987b. PRELIM USERS GUIDE: Documentation for the EPA Computer
Program/Model for Developing Local Limits for Industrial Pretreatment Program at
Publicly Owned Treatment Works. Version 3. Washington, DC: Office of Water
Enforcement and Permits.
U.S. EPA. 1985a. Guidance Manual for Preparation and Review of Removal Credit
Applications. Washington, DC: Office of Water Enforcement and Permits.
U.S. EPA. 1985b. Pretreatment. Implementation Review Task Force: Final Report to the
Administrator. Washington, DC: Office of Water Enforcement and Permits.
U.S. EPA. 1983. Guidance Manual for POTW Pretreatment Program Development.
Washington, DC: Office of Water Enforcement and Permits.
U.S. EPA. 1982. Fate of Priority Pollutants in Publicly Owned Treatment Works. Final
Report and Vol. 1. Washington, DC: Office of Water Regulations and Standards,
Effluent Guidelines Division. EPA 440/1-82/303.
U.S. GAO. 1990. Water Pollution: Serious Problems Confront Emerging Municipal Sludge
Management Program. Washington, DC.
U.S. GAO. 1989. Water Pollution: Improved Monitoring and Enforcement Needed for Toxic
Pollutants Entering Sewers. Washington, DC.
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Hi*: H-K •'.•'• i-'i'l
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6. ADEQUACY OF DATA ON THE ENVIRONMENTAL EFFECTS OF Toxic
DISCHARGES FROM POTWs
Section 519(a)(l) of the Water Quality Act (WQA) of 1987 requires the U.S.
Environmental,-Protection Agency (EPA) to study "the adequacy of data on environmental
impacts of toxic industrial pollutants discharged from publicly owned treatment works
[POTWs]," This chapter addresses that requirement. It also uses available data to indicate
which environmental impacts are caused by the discharge of toxic pollutants by POTWs.
Section 6.1 provides a general overview of the fate and effects of toxic pollutants discharged
to POTWs. This section sets the basis for the evaluation of the adequacy of available data
on discharges and environmental effects.
Sections 6.2 through 6.4 address discharges to surface water, sludge, and air,
respectively. These sections are organized similarly, providing information on the adequacy
of existing data, an analytical framework, and the results of the analysis.
Section 6.2, Surface-Water Effects, is the most detailed of these sections, reflecting the
historical emphasis of EPA's Clean Water Act (CWA) programs. As witnessed by recent
and planned initiatives, the National Pretreatment Program is increasingly emphasizing
sludge quality and worker health and safety issues, and more data are likely to be generated
on these issues as a result. Currently, as shown in Sections 6.3 and 6.4, data on sludge
quality and worker health and safety issues are limited.
Sections 6.2 through 6.4 rely upon quantitative evaluations of national data wherever
possible. However, as noted throughout this chapter and elsewhere in this report, the
absence of comprehensive criteria and standards for surface water, sludge, and air has limited
EPA's ability to gather data that tangibly demonstrate the environmental effects of toxic
discharges from POTWs.
Since more environmental effects data exist at the local than at the national level, EPA
used surrogate and case-study measures of environmental effects in cases where
comprehensive national data were not available. Local program managers must collect such
data to revise pretreatment standards and comply with their permit limits; yet because the
primary audience for such information is not at the national level, it is not reported to national
program managers in a form that is consistent or amenable to quantitative analysis.
6-1
-------
,iii Ii1" 1:11 F,|i: |i ".MI; , Jin i , I ',"• II" J'nkN •'!:»„ 'I'h'.m" 'li,,!,'"!",, '".'.' kill '.,!!, ^TJiVi'iiiiJilli /JlihiliiilliHU1 ! "i:"iiil,,,'i.,ii 'ii1., iihirMiill
Section 6.5 concludes the chapter with a summary list of findings related to data
adequacy of the environmental effects of toxic discharges from POTWs.
6.1 GENERAL FATE AND EFFECTS OF Toxic POLLUTANTS BISCHARGED to POTWS
Chapter 3 of mis report documented the sources anc! kinHs of toxic pollutants that are
discharged to POTWs, indicating the wide range of sources arid large number of pollutants for
which data exist. Chapter 4 determined that removal of toxic pollutants from the
wastestream at treatment plants is highly variable and- discussed the fact that at least some
pollutants do not biodegrade easily or consistently during treatment, but instead partition to
sludge, volatilize to air, or discharge to receiving waters.
Pollutants received by a POTW can be released to the environment at many locations.
Figure 6-1 shows the general locations at a POTW from which pollutants may be released to
air, surface waters, and ground waters. (Other receiving environments may also be affected,
but to a lesser extent Soils, for example, are also considered a receiving environment, but
concerns with soil contamination primarily relate to subsequent ground-water contamination
>,i • • i • i. * "• •,, i1 : .• j , ' • • i " , •",, ,':,•,'" ,, i • ':.,,','• :• ,r"'' 'ni'i' T ir i11 "• i nisi.!' i' i „. ..'! 1. idJ i1:,»', »i ,in'" Lull f,i i: , f' • • „ MI; ,il» , i •,". »•' m, K "\ •, »„ ' :, Hi" ' ii,,!,1" i »„ ' ».•.• j.,,,11. vi, >,, »i •>,' i,1 iiiUiiii
or incorporation into the food chain following sewage sludge disposal—both of which are
discussed under ground-water releases.)
6.1.1 Fate of Toxic Pollutants Discharged to POTWs
The primary purpose of wastewater treatment at a POTW is to reduce the concentration
of conventional pollutants (e.g., biochemical oxygen demand, suspended solids) in
wastewaters so that the environmental impacts of discharges are acceptably small. As noted
in Chapter 4, reductions in concentrations of toxic pollutants typically are incidental to
reductions in conventional pollutants. Conventional, nonconventional, and toxic pollutants
either are destroyed by biological or chemical conversion to less objectionable chemicals, or
they are physically removed from the wastestream.
Pollutant destruction occurs primarily through biological activity; microorganisms
metabolize organic chemicals in wastewater, ultimately converting them to carbon dioxide
and water (in aerobic systems) or to methane (in anaerobic systems). Other elements
attached to organic compounds (such as nitrogen, sulfur, chlorine and other halogens, and
metals) can interfere with such metabolism and make the destruction of organics in treatment
systems less efficient.
6-2
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I
I
i
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-2
I
-------
Pollutants that are not destroyed by biological activity are either physically removed
from wastewaters through volatilization (loss to air) and partitioning to sludge, or else they
remain in the wastestream and are discharged to receiving waters. Any pollutant that is not
destroyed in a POTW has the potential to harm receiving water, air, and ground water. The
next two subsections provide some background on releases from POTWs to air and ground
water.
6.1.1.1 Releases to Air
As Figure 6-i shows, pollutants may volatilize at many locations in a wastewater
treatment plant. Chemicals begin to volatilize in the collection system and are released to
the atmosphere at manholes, pump stations, and the headworks of the treatment system.
Pollutants also volatilize in the treatment system, particularly where there is strong aeration
or turbulence (such as an activated sludge process).
The gases released from POTWs include volatile organic compounds (VOCs), carbon
dioxide, hydrogen suifide, ammonia, and nitrogen. VOCs may be released in the collection
i. ,.',,: . ' « , , ' ;f , .» ";' , i, I i ii; "I,, i ,i u ' ' ,, i , , ;,, ,•„',„,„ II.,.« ' I'hf'J iL Mini 115,1' ,.!,.'" ' .1 I "II1 .. 111 "'I 'i i.i'!,:,'"!l,,,'il!i' .,'•: .' !,', ', I ' "k • („ I"1! il "In 'I
system, at the plant headworks, in aeration tanks, and in the activated sludge process.
These VOCs are typically organic solvents, such as hexane and benzene, and other
compounds used primarily in industrial processes. Other gases are typically created by
microbial activity in sewers or during treatment at the plant. Carbon dioxide is generated by
the aerobic decomposition of organics in the wastestream, hydrogen suifide by the reduction
of organic sulfur compounds, methane by the anaerobic decomposition of organic compounds,
and nitrogen gas by denitrification of inorganic nitrogen compounds. Ammonia may be
1 ' " ' '• ' 'll . „ ' ' '" ',,. '., ' ,,,. i '' , V !.,,„" . ,'„ ,,- J,, ,,i;'» ; !'„• 'Ml, ..:i.|".,, • ' tf! ' .V1 IIP "IHIinliii1 hill',!11'.: i,!lr f1 •' ,"!'nij ,| ''I" j'l *l!:'! ''Ii '• :,'!,:: "i!1, I1 '",',!!': '.'ii'!'1!!',' '.'ill;, :l '
present in large concentrations in the influent or may be generated by biological activity
during treatment. .
Most gaseous releases consist of carbon dioxide or methane, the two major end
products of biological decomposition of organic compounds. The relative volumes of releases
of other chemicals depend on their concentrations (or the concentrations of their precursors)
in the sewage and the extent to which they are decomposed biologically before they have a
chance to volatilize.
In addition to the compounds volatilized during treatment, a small fraction of organic
compounds volatilize from sludge during conditioning or disposal By volume, the amount of"
volatilization from sludge is very small compared to that occurring during treatment. The
gases released consist of carbon dioxide (from aerobic digestion and from chemical oxidation
6-4
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of the organic matter in sludge), methane (from anaerobic digestion), or both (from
composting).
Gaseous emissions also occur during sludge incineration, which is one of the common
disposal methods for sludge for larger POTWs. Typically, the greatest focus has been on
paniculate emissions from sludge incinerators because toxic metals tend to sorb to, and be
\ • ' •
released with, particulates. Mercury and beryllium, however, volatilize at low temperatures
(well below incineration temperatures) and may be emitted even if paniculate emissions are
low. Similarly, small amounts of organic constituents may be formed and released from
incinerator stacks as products of incomplete combustion. The relative importance of metal
and organic emissions depends on the chemical composition and dryness of the sludge,
incinerator design, and operating conditions.
6.1.1.2 Releases to Ground Water
Releases to ground water may occur from a variety of processes at all stages of
municipal wastewater treatment. Under limited circumstances, such as when a sewer is
above the water table, wastewater can exfiltrate from the collection system to ground water.
This mechanism appears to be of only local importance (EPA, 1989); furthermore, it is not
well understood and needs further investigation on a national basis before conclusions can be
drawn about its impact on ground water.
Losses to ground water may also occur when municipal wastewaters are stored or
treated in lagoons. The potential for ground-water contamination from such storage or
treatment practices is low; however, some lagoons with industrial discharges may be
potential sources of ground-water contamination (EPA, 1987).
Finally, and perhaps most importantly, ground-water contamination may occur during or
after disposal of sewage sludge. Sludge is generated during primary and secondary (and
sometimes tertiary) treatment of wastewater. It consists of both inert and organic solids—
some from the influent, some from microbial biomass grown during treatment—in an aqueous
suspension. Many chemicals that have low solubility in water sorb to sludge particles,
particularly metals (such as mercury, cadmium, lead, copper, and zinc) and organic
compounds (such as organochlorine pesticides and PCBs). Since sludges are removed from
the wastestream during clarification, pollutants that partition to sludge are not discharged
directly to receiving waters.
6-5
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The three sludge disposal options with the highest potential for ground-water
contamination are land application, landfilling, and distribution and marketing. Land
application involves the mixing of sludge with, or addition of sludge to, the surface layers of
** ^ n , | , | „ ,,,:.,.: '••,', ™; ,,i: '"1| •!':•,,« ' '! i •;, "liii'vj't! ME'.!!. • ' ;'- '"• v '• \\ " ''': ...'','"I!1 .'' • .,'"•''"' : ., ..s'1 •'
soil for its nutrient and stabilizing properties. Landfilling generally involves placing dried
sludge into a confined area in the ground. Distribution anii marketing involves selling or
giving away sludge, usually in dry form, as a fertilizer or soil conditioner. Regardless of the
disposal method, once sludge is in soil it slowly decomposes, gradually releasing any
contaminants present. Rain water percolating through the soil may leach pollutants to ground
water. , i . \' /'/ ' '.' "wi r_' n •' /' ' i i , ] "'
6.1.1.3 Relative Magnitudes of Releases to Different Environments
When pollutants are not biodegraded, they are released to one or more receiving media.
Most organic compounds, for example, are discharged to surface waters, volatilize to air, and
partition to sludge. The relative amounts released to each medium determine the general
environmental impacts of industrial pollutants discharged to sewers. Overall, about half of
the mass of the most common toxic pollutants that, are released to the environment from
POTWs is released to surface waters (see Figure 6-2; DC, 1989). The remainder of the toxic
metals tends to partition to sludge, and the remainder of the toxic organics tends to volatilize.
Small amounts (up to 3 percent) of the organics partition to sludge (IJC, 1989).
'•',- ' - '', '' . i • ; .-.:.'.:' i
Chapter 4 presents estimates made in the Domestic Sewage Study (DSS) on the
proportions of many toxic pollutants in POTW influent that are discharged to surface waters,
volatilized to air, or partitioned to sludge. Table 6-1 summarizes DSS data for a number of
the more common pollutants. The entries in the table are sorted so that the pollutants
estimated to have the highest potential for discharge to surface waters appear first.
The table shows both single percentages and ranges of percentages for releases of each
chemical to the different environments. As described in Chapter 4, however, actual treatment
system performance in removing toxic pollutants from wastewater may be much more
variable than DSS, estimates indicate. The ranges reflect the differences between acclimated
and unacclimated treatment systems, as estimated during the original study.
6-6
-------
Releases to Air:
Metals: 0%
Organics: 42 %
POTWTreatment
Processes
Releases to Surface Water:
Metals: 53%
Organics: 55 %
Releases to Sludge:
Metals: 47%
Organics: 3%
Sludge Conditioning
and Disposal
Processes
Source: Adapted from IntemationalJoint Commission, 1989
Figure 6-2. Percent of Environmental Releases from POTWs Entering
Air, Water, or Sludge
6-7
-------
Table 6-1. Percentages of Selected Pollutants in POTW Influents
Released to the Environment in Surface Waters, Air, and Sludge1
Pollutant
1,1,2-Trichloroethane*
Nitrobenzene*
1,1,2,2-Tetrachloroethane*
Pentachlorophenol*
Cadmium*
1,2-Dichloroethane*
Bis-2 Chloroethyl Ether*
Methyl Isobutyl Ketone
Methyl Ethyl Ketone
Nickel*
Parathion
Methyl Parathion
Mercury*
Arsenic*
Selenium*
2,4-D
2,4-Dichlorophenol*
2,4,6-Trichlorophenol*
Cyanide*
Antimony*
Dimethyl Phthalate*
2-Chlorophenol*
Lead*
Chromium*
1 ,2-Dichloropropane*
Acrylonitrile*
N-Nitrosodimethyl Amine*
2,4-Dinitrophenol*
Diethyl Phthalate*
Pentachloroethane
Naphthalene*
Formaldehyde
Carbon Tetrachloride*
Chloroform*
Trans- 1 ,2-Dichloroethy lene*
To
Surface Water
20-802
10-80
10 - 80
5-80
73
10-70
10-70
10-70
5-70
65
10-60
10-60
50
50
50
10-50
5-50
5-50
40
40
5-40
5 - 40
30
30
10-30
10-30
10-30
10-30
10-30
5-30
5-30
15 - 20
10-20
10-20
10-20
To
Air
16-40
12.- 36
27 - 45
0-2
0-2
0-3
0-3
45-63
Ot
- 4
• •
42-57
0-4
0 - 4
72
63^72
63-72
To
Sludge
l
2f\
- 9
1 - 4
A "1 ^1
4-17
^T
27
2- 5
3f\
- 9
3g\
- 9
3-10
oc
35
3
3-7
A O
48
Cf\
50
50
4-7
4rt
- 8
40
- 8
fY
57
^A
OU
0.
5O
- 8
*TA
70
70
0
7f\
- 9
7/\
- 9
7f\
- 9
1 i
1
11-14
20 - 27
8-92
91 ^
- 12
2
8-27
*Priority pollutant.
1. Pollutants not released to surface water, air, or sludge are biologically degraded during treatment.
2. Ranges reflect differences between acclimated and nonacclimated treatment systems and natural variability
of treatment efficiency.
Source: Tables 4-7,4-8, and 4-9 in EPA, 1986b.
6-8
-------
Table 6-1. Percentages of Selected Pollutants in POTW Influents
Released to the Environment in. Surface Waters, Air, and Sludge1
, (continued)
Pollutant
Tetrachloroethylene*
2,4-Dimethyl Phenol*
Phenol*
1 ,3-Dichlorobenzene*
1 ,4-Dichlorobenzene*
1,2-Dichlorobenzene*
1,1,1-Tnchloroethane*
Trichloroethylene*
Xylenes
Methoxychlor
Chlorobenzene*
Tetrachlorobenzene
Chlordane*
Barium
Silver*
Bis-2-Ethylhexyl Phthalate*
Aldrin*
1 , 1 -Dichloroethylene*
Toxaphene*
Benzene*
Ethyl Benzene* .
Toluene*
1,1,2,2-Tetrachloroethane*
Hexachloro- 1 ,3-Butadiene*
Hexachloroethane*
Butyl Benzyl Phthalate*
Endrin*
PCS*
Acrolein*
To
Surface Water
10-20
5-20
5-20
10 - 15
10-15
10-15
5-15
5-15
5-15
10
10
10
10
10
10
10
10
5-10
5 - 10
5-10
5-10
5- 10
5 - 10
5-10
5-10
5-10
5-10
8
5
To
Air
45-64
45-77
45-77
45 - 77 '
76 - 77
,67 - 68
24-68
54
27-45
27
9
,
76-81
57 - 72
24-72
24-72
22-72
48-63
0-5
0-5
9
0-5
To
Sludge
2 - 3
6-8
12-14
3
9 - 23
9-32
1
5-6
13-14
8
14
33
33
90
90
66
33
0
4
.' • 2 ':
5-6
18-27
4
8-9
8-9
41 - 43
33 - 35
22:
•10
*Priority pollutant.
1. Pollutants not released to surface water, air, or sludge are biologically degraded during treatment.
2. Ranges reflect differences between acclimated and nonacclimated treatment systems and natural variability
. of treatment efficiency.
Source: Tables 4-7,4-8, and 4-9 in EPA, 1986b.
6-9
-------
EPA estimates that about half the compounds in Table 6-1 may have less than 20
percent of their influent mass discharged to surface waters under unacclimated conditions.1
'hi. i ' . .' f i , • •
The table also indicates that a number of organic pollutants, but few of the metals, may
be removed from the aquatic wastestream through volatilization^—particularly the chlorinated
benzenes and the low carbon chlorinated alkanes (e.g., the tetrachlbroethanes).
Based on this table, it is apparent that the destruction of toxic organic compounds is
limited and that metals are not destroyed at all. Overall, the DSS (EPA, 1986b) concluded
that 14 to 25 percent of the mass of all toxic pollutants volatilizes to air, 43 to 62 percent
biodegrades, 14 to 16 percent partitions to sludge, and 8 to 18 percent is discharged to
surface waters. Specific pollutants, however, particularly metals, are much more likely to be
discharged to surface waters and partition to sludge than the most common toxic organic
compounds.
6.1 Jt Toxic Effects of Commonly Released Toxic Pollutants
Toxic effects can be seen at all levels of the organization hi the biological system: at the
ecosystem level, through changes in system biomass, productivity, or nutrient cycling; at the
community level, through changes in community structure, species diversity, or species
1 i"?! „ , ; , •,,;-' '!' " : ", -' ,. Vi, i;-1 isn;;.,..;;.i ,; il',;!«.;,"(S'r !f: HUff •pMK.aiHIiMtff,i,'f!. Kill'iiTi'""<>IVTiSW-'SIf'ii •<;! BHMittflr <'« ,:"#• i i '
'. i , " i:,1 . " " III Till
Several tests are available that measure the toxicity of chemicals. Some measure the
i,;,1! , .'. ' ." iii in i iir ii i i i i n i
toxicity of a substance by injecting it into the body, some by exposure as gases, some in food
or water, and some by inhalation. Each species reacts in a slightly different way to
exposures by different routes, but in general, more-toxic chemicals exert effects at lower
concentrations than less-toxic chemicals. Therefore, the concentration at which a chemical
exerts a toxic effect indicates how serious an effect it may have in the environment.
1. As discussed in Chapter 4, unacclimated conditions are likely to provide a. better
approximation of full-scale POTW performance.
'•:,' .',••:.:••,•! • ' I ' i I ii1 1
• .' •'• -i :• ,•• • ill
6-10
-------
Toxicological studies generally focus on four major categories of effects: lethal,
carcinogenic, teratogenic, and mutagenic. Lethal effects are those that cause death, usually
after exposure to chemicals for short durations. For this reason, tests that measure lethality
are often called acute tests. Tests that measure carcinogenic (cancer producing), teratogenic
(producing developmental abnormalities), or mutagenic (producing genetic abnormalities)
effects are often considered chronic tests, because the effects being measured are normally
observed only over longer exposures.
Over the last several years, considerable research has been conducted on the toxic
effects of a large number of pollutants. The Agency has compiled lists of hundreds of
compounds that have significant effects on biota, including humans. Table 6-2 lists the toxic
characteristics of a small subset of these compounds (primarily, CWA priority pollutants)
according to their lethal, carcinogenic, teratogenic, mutagenic, and bioaccumulative potential.
Table 6-2 also indicates persistence to incorporate some measure of the length of time that
the pollutant may exert an effect after release into the environment.
The criterion for listing a compound in a particular category of effect was whether it was
known to cause the effect at a concentration less than a predetermined value. A compound is
considered lethal if it kills 50 percent of the organisms in a toxicity test (the LCso) at less
than (i.e., its LCso is less than) 10 milligrams per liter in an aquatic environment or 100
milligrams per cubic meter in air. To ascertain whether a compound had these effects, EPA
used data from the National Institute of Occupational Safety and Health's Registry of Toxic
Effects of Chemical Substances (RTECS), which contains evaluations of the literature on
many toxicity test results, including an assessment as to whether the data on each compound
indicate that it is a known or suspected carcinogen, teratogen, or mutagen.
Finally, chemicals that have foioconcentration factors greater than 1,000 were listed as
bioaceumulative. A bioconcentration factor (BCF) is a measure of a chemical's tendency to
concentrate in tissues of aquatic organisms. There are two primary means of deriving BCFs:
from experimental measures or prediction using structure-activity relationships. The most
common method used to calculate a BCF is to divide the measured concentration of the
chemical of concern in the exposed tissue by the measured concentration of the chemical in
the exposure water, after a steady-state condition is reached, i.e.,
_ _ Concentration in tissue
~ Concentration in water
6-11
-------
Table 6-2. Toxic Effects of Common Pollutants in Aquatic and Terrestrial
Environments
ijiii'"iii'ii'iiii'liSiiii,!1'1;. sir1 v I'ls
Pollutant
Lethal1 Carcinogenic^ Teratogenic^ Mutagenic^ Bioaccumulative-* Persistent^
DDT*
Dioxin (2,3,7,8-TCDD)*
PCBs*
Arsenic (trivalent)*
Aldrin*
Toxaphene*
Dieldrin*
Carbon Tetrachloride*
Hexachlorobutadiene*
Benzene*
Formaldehyde
Hexachlorocyclohexane - gamma*
Methylene Chloride*
Ethylhexyl Phthalate, bis 2*
Chlordane*
DDT Metabolite, DDE*
Heptachlor*
DDT Metabolite, TDE*
Beryllium*
Dichlorobenzidine*
Hexachlorocyclohexane - Alpha*
Hexachloroethane*
Hexachlorocyclohexane - Technical
Cadmium*
Endrin*
Hexachlorobenzene*
Nickel*
Methoxychlor
Mirex
Lead*
Chlorpyrifos
Ethylbenzene*
Pcntachlorophenol*
Toluene*
Malathion
Demeton
HI-'
*Priority pollutant. .
1. Has water quality criterion <10 mg/1 or acute or air quality criterion <100 mg/m3.
2. Listed in RTECS as a carcinogen or suspected carcinogen. -
•,:» .'. ,,. .. • , ., ',"• ;,:,,- ,'. f, mil !!• • • j -i -..,..' '-,• f'l'.ft •,'. i.' ••. '.;,. "•','" •'.;•,•• '•'•,', i ,' >' i; "•:>", i 1
3. Listed in RTECS as a teratogen or suspected teratogen.
4. Listed in RTECS as a mutagen or suspected mutagen.
5. Has bioconcentration factor Sl.OOO as documented in PHRED (Public Health Risk Evaluation Database 1987) or
in Water-Related Environmental Fate of 129 Priority Pollutants (EPA, 1979).
6. Has environmental half-life 2:365 days as documented in PHRED.
Key: ' V = has characteristic; "-" = does not have characteristic; blank = no data.
6-12
-------
Table 6-2. Toxic Effects of Common Pollutants in Aquatic and Terrestrial
Environments (continued)
Pollutant
Lethal1 Carcinogenic2 Teratogenic3 Mutagenic4 Bioaccumulative5 Persistent6
Endosulfan* . +
Guthion +
Copper* +
Selenium* +
Hexachlorocyclopentadiene* +
BHC* +
Mercury* +
Chlorine +
Ammonia +
Chloroisopropyl Ether (bis-2)* +
Diriitro-O-Cresol 2,4 +
Isophorone* +
Chlorophenol 4 +
Hexane (n-hexane) +
Parathion +
Cyanide* +
Silver* +
Zinc* , . +
Thallium* +
Chromium (hexavalent)* +
Barium +
Chlorophenol 2* +
Dimethyl Phenol 2,4* +
Chromium (Trivalent)* +
Pentachlorinated Ethanes .+
Manganese +
Aluminum +
Chlorinated Naphthylenes +
Chlorotoluene O . • , +
Methyl Isobutyl Ketone +
Sulfide-Hydrogen Sulfide +
Polynuclear Aromatic Hydrocarbons -
Chloroform*
Vinyl Chloride*
Tetrachloroethylenes* -
Trichloroethylene* -
Dinitrotoluene** -
*Priority pollutant.
1. Has water quality criterion <10 mg/l or acute or air quality criterion <100 mg/m3.
2. Listed in RTECS as a carcinogen or suspected carcinogen.
3. Listed in RTECS as a teratogen or suspected teratogen. -
4. Listed in RTECS as a mutagen or suspected mutagen.
5. Has bioconcentration factor £1,000 as documented in PHRED (Public Health Risk Evaluation Database 1987) or
in Water-Related Environmental Fate of 129 Priority Pollutants (EPA, 1979).
6. Has environmental half-life >365 days as documented in PHRED. .
Key: "+" = has characteristic; "-" = does not have characteristic; blank = no data.
6-13
-------
Table 6-2. Toxic Effects of Common Pollutants in Aquatic and Terrestrial
Environments (continued)
Pollutant
Lethal1 Carcinogenic2 Teratogenic3 Mutagenic4Bioaccumulative5 Persistent6
Dinitrotoluene 2,4* -
Acrylonitrile* -
Nitrosodimethylamine N* -
Xylene -
Nitrosodibutylamine N -
Nitrosodiethylamine N
Arsenic* - -
Arsenic (penjavalent) -
Trichlorophenol 2,4,6*
Asbestos* -
Tetrachl&roethane 1,1,2,2*
Benzidene* -
Chlorinated Benzenes -
Dichloroethane 1,2*
Trichloroethane 1,1,2* -
Nitrosodiphenylamine N* -
Nitrosopyrolidine N* -
Dichloroethylenes -
Hexachlorocyclohexane - Beta*
Trichlorinated Ethanes
Halomethanes . -
Nitrosamines -
Tctrachlorophenol 2,3,4,6
Trichloroethane 1,1,1*
Dichlorobenzenes -
Dimethyl Phthalate*
Methyl Ethyl Ketone
Monochlorobenzene -
Naphthalene* -
Phenol*
Diethyl Phthalate*
Chlorophenoxy Herbicides (2,4-D) -
Dibutyl Phthalate
Pentachlorobenzene -
Dichlorophenol 2,4* -
*Priority pollutant.
1. Has water quality criterion <10 mg/l or acute or air quality criterion <100 mg/m3.
2. Listed in RTECS as a carcinogen or suspected carcinogen.
3. Listed in RTECS as a teratogeri or suspected teratogen.
4. Listed in RTECS as a mutagen or suspected mutagen.
5. Has bioconcentratibn factor £1,000 as documented in PHRED (Public Health Risk Evaluation Database 1987)
in Water-Related Environmental Fate of 129 Priority Pollutants (pPA., 19J9).
6. Has environmental naif-life >365 days as documented in PHRED.
Key: "+" = has characteristic; "-" = does not have characteristic; blank = no data.
or
6-14
-------
Table 6-2. Toxic Effects of Common Pollutants in Aquatic and Terrestrial
Environments (continued)
Pollutant Lethal1 Carcinogenic2 Teratogenic3 Mutagenic4 Bioaccumulative5 Persistent6
Chlorophenoxy Herbicides (2,4,5,-TP)
Carbon Dioxide -
Fluoranthene* -
Acrolein? -,
Tetrachloroethanes* -
Nitrobenzene* -
Acenaphthene* -
Dichloropropane* —
Dichloropropene
Diphenylhydrazine 1,2*
Nitrophenols -
Chloride
Diphenylhydrazine1"
Antimony*
Tetrachlorobenzene 1,2,4,5
Dinitriphenols
Trichlorophenol 2,4,5 -
Chloro-4 Methyl-3 Phenol -
Iron -
Pthalate Esters -
Haloethers
Chloroalkyl Ethers
Chloroethyl Ether (bis-2)*
*Priority pollutant.
1. Has water quality criterion <10 mg/l or acute or air quality criterion <100 mg/m3.
2. Listed in RTECS as a carcinogen or suspected carcinogen.
3. Listed in RTECS as a teratogen or suspected teratogen.
4. Listed in RTECS as a mutagen or suspected mutagen.
5. Has bioconcentration factor >1,OOQ as documented in PHRED (Public Health Risk Evaluation Database 1987) or
in Water-Related Environmental Fate of 129 Priority Pollutants (EPA, 1979).
6. Has environmental half-life >365 days as documented in PHRED.
Key: 'V = has characteristic; "-" = does not have characteristic; blank = no data.
6-15
-------
Bioconcentration factors can also be calculated experimentally by dividing a chemical's
kinetic uptake rate (ki) by its elimination rate (k2), i.e.,
Alternatively, a BCF can be estimated using structure-activity relationships based on a
well-documented relationship between the BCF and the n-octanol/water partition coefficient
for organic chemicals.
i , , '' . • • •'•,',",, »i'i|i , -I in-'1,' ii;> i ',•,„",, •!,., "V ...... i ,,n ,"!PIL,,J/ '", i1 1,1 , ' . , • ' i n ' h .• ., H ',,'"! «' i
The chemicals in Table 6-2 are listed in descending order of an estimated magnitude of
environmental harm. This order was determined by assuming that a substance with a lethal
effect is more damaging than one that is carcinogenic. Similarly, a compound that is lethal,
carcinogenic, and teratogenic was assumed to be more harmful than one that is only lethal
and carcinogenic. Most heavy metals and pesticides appear near the top of this list; those
compounds that exert few effects (or for which there are inadequate data) appear near the
end. i ..... h , '',..-.,;,.,,
In Table 6-3, EPA sorted the most current values of water quality criteria, developed by
EPA's Criteria an.". I "'A;; ill!'! .'•,'. Ill I III II I I " II I III I II
and the criterion to protect human health (for consumption of fish and water). The primary
sort was on the acute values and the secondary sort on chronic values. As was the case in
Table 6-2, pesticides and heavy metals appear near the top of the list. It is also significant
that the chemicals deemed the most toxic (i.e., are toxic at lower concentrations), as
indicated by the water quality criteria, are also listed as persistent in Table 6-2; these
compounds are not easily degraded and exert their toxic effects for years or decades if
present in sufficiently high concentrations.
6.2 SURFACE-WATER EFFECTS
This section discusses the sources and adequacy of data concerning the effects on
surface water of toxic pollutant discharges from POTWs, a methodology for determining tnose
effects, and the results of employing the methodology.
6.2.1 Sources and Adequacy of Data
A variety of information sources can be used to assess the impacts of toxic pollutant
discharges by POTWs. As the previous section indicated, substantial information exists on
6-16
-------
Table 6-3. Water Quality Criteria for Compounds With Acute or Chronic
Freshwater Criteria*
Freshwater
Dioxin (2,3,7,8 - TCDD)
Parathion ,
Toxaphene
Chlorpyrifos ':
Endrin
Endosulfan
Heptachlor .
DDT Metabolite, TDE
DDT
Acute
<0.01
0.065
0.073
0.083
0.18
0.22
0.52
0.60
1.1 ng
Hexachlorocyclohexane (Lindane) 2.0
PCBs
Chlordane
Mercury
Dieldrin
Aldrin
Cadmium
Silver
Hexachlorocyclopentadiene
Chromium (hexavalent)
Copper
Chlorine
Pentachlorophenol
Selenium
Cyanide
Phenol, 4-Chloro 3-Methyl
Acrolein
Lead
Hexachlorobutadiene
BHC
Zinc
Beryllium
Nitrophenols
Chlorinated Benzenes
Diphenylhydrazine, 1,2-
Dinitrotoluene
Arsenic (trivalent)
Haloethers
Arsenic (pentavalent)
Phthalate Esters
Hexachloroethane
DDT Metabolite, DDE
Dichlorobenzenes
Nickel
2.0 ng
2.4
2.4
2,5 ng
3.0 ng
3.9
4.1
7.0
16
18
19
20
20
22
30
68
82
90
100
120
130
230
250
270
330
360
360
850
940
980
1,050
1,120
1,400
Chronic
Marine
Acute
Chronic
<0.00001
0.013
0.0002
0.041
0.0023
0.056
0.0038
0.001
0.08
0.014
0.0043
, 0.012
0.0019
1.1
0.12
5.2
11
12
11
13
5
5.2
21
3.2
9.3
110
5.3
150
50
230
190
122
48
3
540
763
160
0.021
0.011
0.037
0.034
0.053
3.6
0.13
0.16
10
0.09
2.1
0.71
1.3
43
2.3
7
1,100
2.9
13
13
300 .
1
55
140
32
0.34
95
4,850
160
590
69
• (
2,319
2,944
940
14
1,970
75
0.0002
0.0056
0.0023 -
0.0087
0.0036
0.001
0.03
0.004
0.025
0:0019
9.3
50
2.9
7.5
7.9
71
1
5.6
86
129
370
36
13
3.4
8.3
Fish and
Water
IxlO-5 ng/1
0.71 ng/1
1
74
0.28 ng/1
,
0.024 ng/1
0:079 ng/1
0.46 ng/1
144 ng/1
0.071 ng/1
0.074 ng/1
10
50
206
50
1.01 mg/1
10
200
320 -
50
0.45
6.8 ng/1
488
1.9
400
13.4
Fish
1 x lO'5 ng/1
0.73 ng/1
159
0.29 ng/1
0.024
0.079
0.48 ng/1
146 ng/1
0.076
0.079
'
780
50 :
117 ng/1
'
8.74
2.6 mg/1
100
* All values in (ig/1 unless otherwise marked.
6-17
-------
Table 6-3. Water Quality Criteria for Compounds With Acute or Chronic
Freshwater Criteria* (continued)
*
Thallium
Chlorinated Naphthalenes
Acenaphthene
Chromium (divalent)
Dichlorophenol, 2,4-
Dimethyl Phenol, 2,4-
Naphthalene
Benzidine
Fluoranthene
Chlorophenol, 2-
Tetrachloroethylenes
Benzene
Nitrosamines
Dichloropropene
Pcntachlorinated Ethanes
Acrylonitrile
Antimony
Tetrachloroethanes
Phenol
Halomethanes
Dichloroethylenes
Toluene
Trichlorinated Ethanes
Dichloropropane
Nitrobenzene
Chloroform
Ethylbenzene
Carbon Tetrachloride
Trichloroethylene
Isophorone
Dichloroethane, 1,2-
Chloroalkyl Ethers
Chloride
Mirex
Guthion
Methoxychlor
Malathion
Demcton
Sulfide-Hydrogen Sulfide
Trichlorophenol, 2,4,6-
Iron
Tetrachloroethane, 1,1,2,2-
Trichloroethane 1,1,2
Freshwater
Acute
1,400
1,600
1,700
1,700
2,020
2,120
2,300
2,500
3,980
4,380
5,280
5,300
5,850
6,060
7,240
7,550
9,000
9,320
10,200
11,000
11,600
17,500
18,000
23,000
27,000
28,900
32,000
35,200
45,000
117,000
118,000
238,000
860,000
Marine
Chronic Acute
40
520
.210
365
620
2,000
840
244
1,100
2,600
1,600
2,560
5,700
1,240
21,900
20,000
230,000
2,130
7.5
970
10,300
2,350
40
10,200
5,100
3,300,000
790
390
5,800
12,000
224,000
6,300
10300
6,680
430
50,000
2,000
12,900
113,000
0.001
0.01
0.03
0.1
0.1
2
970
' 1,000
2,400
9,400
9,020
Chronic
710
>
16
450
700
281
6,400
5,000 .
3,040
0.001
0.01
0.03
0.01
0.1
2
Fish and
Water
13.0
170
3.09
0.12
42
0.8
0.66
0.8
87
0.058
146
3.5
0.19
0.033
14.3
19.8
0.19
1.4
. 0.4
2.7
5.2
0.94
100
1.2
0.3
0.17
0.60
mg/1
mg/1
ng/1
ng/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
Fish
48
**
0.53
54.
8.85
40
1.24
• 14.1
0.65
45.0
15.7
1.85
424
15.7
3.28
6.94
80.7
520
243
3.6
10.7
41.8
g
ng/1
mg/1
mg/1
J
mg/1 |
^
mg/1
mg/1
I
*A11 values in jig/1 unless otherwise marked. .
**Level of chromium (trivalent) likely to adversely affect freshwater organisms and must be estimated based upon
water hardness.
Source: EPA (1986a).
6-18
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the toxic effects of individual pollutants in both aquatic and terrestrial systems. These data
are useful in identifying pollutants that pose risks to the environment and the relative
concentrations at which adverse effects might be expected. However, they are limited in their
ability to predict actual effects of POTW discharges on specific individuals or populations due
to the complexity of chemical, physical, and biological components of the discharge and the
receiving environment.
National data bases, developed and maintained by the Agency for storing and retrieving
data on the aquatic environment and for monitoring compliance with National Pollutant
Discharge Elimination System (NPDES) and pretreatmerit regulations, provide only some of
the data necessary to fully address environmental impacts. For example, STORET, a large
data base containing monitoring data on the vast majority of the Nation's waterways, cannot
be used to determine the environmental effects of POTW discharges nationwide because the
concentrations of chemicals and the biotic characteristics stored in STORET reflect a wide
variety of factors that would have to be controlled to separate out the effects of POTW
discharges. These factors include other point and nonpoint source discharges, stream flow,
and other water body characteristics. Assessing the relative importance of these or other
factors for thousands of POTWs was beyond the resources available for this study.
The Agency does have access to information that provides insight into the magnitude of
surface-water effects of toxic pollutant discharges. The first is information contained in
reports prepared by States on the overall quality of their waters and the reasons for their
failure to attain "fishable, swimmable" standards. This nationwide assessment, completed
every 2 years under Section 305(b) of the CWA, provides a general understanding of the
relative magnitude of problems caused by discharges of toxic pollutants (versus other types
of pollutants) and by POTWs (versus other sources).
In a similar way, the Permit Compliance System (PCS), a national data base containing
information on the compliance, of POTWs (and other dischargers) with their NPDES permits,
allows a partial assessment of surface-water effects. PCS allows, but does not require,
users to input pollutant and flow data for then: discharges. Where this facility has been used*
the data can be accessed on a nationwide basis. As explained in Chapter 2, however, PCS
does not contain sufficient data in many fields to perform a defensible assessment (largely
because it was designed and is used for purposes described in Chapter 2, and not for the uses
required for this report). Thus, PCS data must be matched and supplemented with data from
6-19
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other sources before meaningful results can be obtained. Such an approach was taken in this
analysis, as described in the following subsection.
Methodologies for Determining Impacts
EPA conducted three separate analyses to assess the aquatic impacts of discharges of
toxic chemicals from POTWs. The first, based on data provided by States in their 305(b)
reports, indicates the overall importance of toxic discharges in preventing the attainment of
designated uses in water bodies and independently indicates the importance of POTW
contributions in failures to attain designated uses. The second uses data from a variety of
sources to calculate the number of exceedances of Federal water quality criteria potentially
caused by discharges of toxic chemicals from POTWs. The third uses data from PCS to
indicate the number of exceedances of the Federal toxicity criteria by POTW discharges. The
following subsections summarize how these analyses were conducted.
6.2.2.1 305(b) Summary Data
During 1988, EPA requested States to prepare reports on water quality for the Report
to Congress required by Section 305(b) of the CWA In guidance provided to the States,
EPA sought specific information on a number of topics, including the pollutants responsible for
nonattainment of use designations for receiving waters and the sources of those pollutants
(e.g., nonpoint sources, municipal or industrial point sources). EPA prepared tables
summarizing these data on a nationwide basis. Detailed information was presented in EPA's
National Water Quality Inventory 1988 Report to Congress (EPA, 1990a) and is summarized
in Subsection 6.2.3. -
6.2.2.2 Water Quality Criterion Exceedances
In its second analysis, EPA combined data from three naSonaY data bases to calculate
the likely prevalence with which water quality .criteria are being exceeded nationwide.
Described in more detail in .Chapter 2, these data bases were as follows:
:"f ;1:;"*' ' . '.'I','"': i ' I'll i1 I! i 'ii
• PCS, which contains data on 15,747 POTWs. Of "major interest from PCS was
monitoring data on the concentrations of pollutants in discharges.
• NEEDS '88, which contains data on 15,591 poTWs. Data obtainedi from NEEDS
included individual POTW flows and the discharge reach (i.e., receiving water body)
for each POTW. ' '' ,' \ .,. ' _, \' .' '", [''"',,'" [' " 1 \ '.'J '",1171111.",'','.."1 1 '.., .1.1 '11 . 11
- - ."'i-i1 •!'/ .• - :, !' •' •'• ;"", 'ii1 "i'S '<''V jijii'.,!'',::''^L- iitik!' I'.wieiiuii'Vi i"!*i,':i"i:i:iiJt iif-y. 'iwiV'',Kir-••'!'•. si.i'fytflJii
* GAGE File, a national data base containing receiving water flow information for most
reaches within the United States. Of particular interest was the 7-day low flow that
recurs in 10 years (the 7Q10), an important design flow for developing water quality-
6-20
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based effluent limitations for discharges to surface waters, and the flow used for
predicting water quality criterion exceedances in this analysis.
"v ' . , '
PCS and NEEDS had several common elements, including names of POTWs, operating
authority, locations, discharge volumes, and NPDES permit number. Of these items, the
NPDES permit number was the shared element that allowed the simplest matching between
the two data sets. For those numbers that did not match, EPA compared location, authority,
design flow, and other types of information. If the NEEDS POTW matched the PCS POTW in
two or three ways (e.g., matched three of the following: same city, same authority, same
name, same location, approximately the same flow), they were assumed to be the same
POTW. If, however, any of the nonmatching fields indicated that the plants were different,
both were dropped from the analysis (an order-of-magnitude difference in design flows was
often a reason for eliminating plants from the merge). Of the more than 15,000 plants in each
data base, 12,249 plants (more than 80 percent) matched.
After eliminating all unmatched records, the remainder of PCS was then searched for
data on concentrations of pollutants for which EPA has developed water quality criteria (see
Table 6-3). Of the 12,249 POTWs in the PCS/NEEDS match, 7,778 had no data in PCS on
effluent concentrations, leaving 4,471 plants (37 percent of the matched POTWs) with at
least some data on both pollutant concentrations and plant flow.
-i ' ' i- • . • . •*'••"'
The 4,471 plants were then matched with the GAGE data for receiving water flow
information. Of these plants, 731 (16 percent of the matched plants with data) could not be
matched to receiving waters for which there were flow data. Therefore, the data available for
analysis concerned 3,740 POTWs, about 25 percent of the original data set of more than
15,000 POTWs.
Data on these 3,740 POTWs were available regarding toxic pollutant concentrations in
their effluents (from PCS), average discharge flow (from NEEDS), and receiving water flow
(from GAGE). Data on these plants could, therefore, be used to calculate the receiving water
concentration of each pollutant that would have resulted, under low flow conditions, from the
POTW's average discharge assuming no pollutants in the receiving water. This calculation
used the following equation:
6-21
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Cr = (Ce*Qe)/(Qe
where:
Cr = Concentration of the pollutant in the receiving water
Q = Concentration of the pollutant in the effluent
Qe = Flow volume of the effluent
Qr = Flow volume of the receiving water (based on 7Q10).
1 ' ^ ,','/"'"''',"
The values for Ce for each plant were calculated as the arithmetic mean of all data for a
parameter for a plant. Concentration values marked as "less than" or "nondetected" values
were entered as one-half of the detection limit value. Concentration values marked as
"greater than" values were eliminated from the analysis. If all values for a POTW were
listed as not detected, the plant was counted as having data, but no receiving water
concentration was calculated, and the plant was deemed to have a receiving water
concentration that was less than EPA's water quality criterion for that pollutant.
To identify the potential environmental impacts of the concentrations derived for
pollutants in'receiving water, EPA compared the derived receiving-water concentrations to
Federal ambient water quality criteria. As discussed in Subsection 5.3.1.1, Federal water
quality criteria are intended to protect the highest uses of surface waters and are the basis of
State-developed water quality standards, which are intended to protect various levels of
designated uses.
In this analysis, EPA used Federal water quality criteria rather than State standards as
its benchmark for water quality exceedances, even though POTWs are subject to State
standards and although (as Chapter 5 noted) local limits and NPDES permit limits are
designed to protect State-designated uses. EPA used pederal criteria because they are
developed with consistent methods and purpose, cover a wide range of pollutants, and are
intended to protect the highest uses of surface waters. Conversely, State standards vary in
value, encompass fewer pollutants, and do not exit for some pollutants in some States.
Finally, for each plant for which effluent concentrations were derived, a tally was kept of
the number that did not meet the water quality criterion for a particular pollutant out of the
total number of plants that measured for that pollutant. This number was reported as a
percentage of the plants monitoring for the pollutant and is presented and discussed in
Subsection 6.2.3.
6-22
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6.2.2.3 Toxicity
A toxicity test is a laboratory procedure that uses test organisms to indicate the toxicity
of a gas or a solution. Results are normally expressed in terms of the LCso (the
concentration at which 50 percent of organisms are killed over a given exposure period), the
ECso (the concentration at which 50 percent show some predetermined effect), and the
NOEC (the concentration at which no observed effect will occur at continuous exposure to
test organisms).
Toxicity tests are used on POTW effluents to determine whether a chemical or a group
of chemicals are causing the effluent to be toxic, regardless of whether their identities are
known. Whole-effluent toxicity testing enables POTWs to characterize toxicity in their
effluents and to limit it if necessary. Such toxicity may be attributable to non-priority
pollutants, complex pollutant mixtures, or chemicals added or created during the treatment
process at POTWs. EPA's July 24, 1990, revisions to the General Pretreatment Regulations
require pretreatment POTWs and POTWs with greater-than-1-mgd flows to provide whole-
effluent toxicity testing results to their approval authorities as part of their NPDES permit
applications: Implementation of this requirement ultimately will improve awareness of
POTWs' impacts on receiving waters at both the local and the approval authority levels.
PCS maintains separate data fields for effluent test results of different lengths of time,
different species, and different exposure mechanisms (static, static renewal, and flow
through). For this analysis, test results from one of four data fields were converted to toxic
units, according to procedures explained in the Technical Support Document for Water
Quality-Based Toxics Control (EPA, 1985). Toxic discharges then were diluted in receiving
waters as if they were concentrations, as explained previously. The resulting receiving water
concentrations were compared with EPA's Criterion Maximum Concentration (CMC) for
toxicity (i.e., 0.3 acute toxic units, TUa) or the Criterion Continuous Concentration (CCC)
(Le., 1 chronic toxic unit, TUC)(EPA, 1985). Tallies were kept of the numbers of POTWs that
exceeded either criterion and the total number of plants that conducted toxic tests on the
effluent. . . •
In addition, some toxicity tests in PCS are reported with pass/fail results. Pass/fail
tests are typically specified as measurements at the end of a discharge pipe (i.e., they do not
allow for dilution). Pass/fail tests are summarized by counting the number of passes and fails
for each test across all plants and calculating the overall percentage of tests that passed.
The results of these analyses are reported in the next subsection.
6-23
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6.2.3 Results ^
This subsection presents the results of the three analyses described in Subsection
6.2.2.
,! •• " .' ..;,.•..:.•,'' ili ii I ,
6.2.3*1 305(b) Summary Data
;',•'. • • "', , • ',"" '; I , . '...'<; .1. i ill ill I,
For EPA's 1988 biennial 305(b) Report to Congress, States assessed and reported on
29 percent of river and stream miles, 41 percent of lake acres, and 76 percent of estuarine
square miles nationwide. Of the water bodies assessed, 30 percent" of river waters, 27
percent of lake waters, and 29 percent of estuarine waters were reported as either not
attaining or partially attaining designated uses.
States were asked to identify the causes of failure of these waters to fully support
designated uses. Table 6-4 summarizes the State-reported data for 1988 on the extent to
which rivers, lakes, and estuaries failed to meet use designations for the reasons indicated.
The table indicates that of the three categories of toxic pollutants for which data were
available (and for those waters for which States reported partial or nonattainrnent), toxic
metals were responsible for 11 percent of the river miles, 7 percent of5 the lake acres, and 9
percent of the area of estuaries and coastal areas that failed to> meet use designations.
Pesticides were responsible for 10 percent of the river mile failures, 5 percent of the lake acre
failures, and 1 percent of the estuarine and coastal area failures. Finally, priority organic
pollutants were responsible for failure of about 8 percent of the lakes and 4 percent of the
coastal areas to attain applicable use designations.
According to Table 6-4, nearly 50 percent of the failures in use attainability are
attributable to causes other than toxic pollutants. Nutrients, pathogens, siltation, and organic
enrichment are all given higher overall rankings than known toxic chemicals in causing
failures to meet use designations. Few independent data can be used to verify the accuracy
of this estimate. There are at least two reasons why other causes are indicated more
frequently than toxics.
First, the determination of use attainability depends on the existence of State water
quality standards for the pollutants of interest and a monitoring program for concentrations of
those pollutants in receiving waters. If States in general did not have water quality
standards for toxic pollutants when reporting under 305(b), the relative importance of toxic
pollutants in causing use nonattainrnent would be underestimated. States have more
-------
Table 6-4. Amount of Assessed Surface Waters Not Fully Meeting Use
Designations in 1988 Because of the Cause Listed (from all sources)
Rivers
(thousands of miles [%])*
Nutrients
Pathogens
Siltation
Organic Enrichment
Metals
Oil and Grease
Salinity
Habitat Modification
Pesticides .
Suspended Solids
Priority Organics
pH
Flow Alteration
Unknown Toxics
Thermal Modification
Other Inorganics
38.0
26.6
60.6
20.9
15.5,
ND3
8.7
8.2
14.7
8.9
ND
7.3
8.3
ND
3.5
' ND
(26.6)2
(18.6)
(42.4)
(14.6)
(10.8)
ND
(6.1)
(5.7)
(10.3)
(6.2)
ND
,- (5.1)
(5.8)
ND
(2.4)
ND
Lakes Estuaries
(millions of acres [%]) (thousands of sq. miles [%])
1.297
0.228
0.677
0.672
0.198
ND
0.380
0.301
0.141
0.200
, 0.217
0.137
0.087
ND
ND
ND'
(48.8)
(8.6)
.(25.4)
(25.3)
(7.4)
ND
(14.3)
(11.3)
(5.3)
(7.5)
(8.2)
(5.1)
(3.3)
ND
ND
ND
3.424
3.320
0.463
2.001
0.655
1.617
ND
ND
0.072
ND
0.283
0.028
ND
0.353
ND
0.036
(49.6)
(48.1)
(6.7)
(29.0)
(9.0)
(23.4)
ND
ND
(1-0)
ND
(4.1)
(0.4)
ND
(5.1)
ND
(0.5)
1. Percentages are of miles (rivers), acres (lakes), and square miles (estuaries) reported by States as not fully
meeting designated uses, not of total miles, acres, or square miles.
2. Percentages sum to greater than 100% because some uses may not be met for more than one reason.
3. ND = Nodata.
Source: EPA (1990a).
6-25
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standards for toxic pollutants now than in 1986 and 1987, when the data for the most recent
305(b) Report to Congress were being generated. Forty or more States (see Table 5-4 and
Appendix C-2) currently have standards for all metals except beryllium (24 States have
standards), nickel (34 States), thallium (19 States), and copper (39 States). Fewer than 24
States have standards for organic priority pollutants except for pCBs (40 States), pesticides
(7 to 41 States, depending on the pesticide), phenol (33 States), arid pentachlorophenol (27
States).
* , ' ' „,,"•"
Second, problems attributable to toxic pollutants may be masked by problems from other
pollutants, such as nutrients, particularly in States where there are few water quality
standards for toxic pollutants or little data on the incidence of toxics.
"Municipal" sources of pollutants (POTWs and CSOs [combined sewer overflows])
are seen by the States to be significant contributors to use attainability problems. In Table
6-5, for example, municipal sources are listed as second in importance only to agriculture in
causing use nonattainability. However, the effects attributed to municipal sources under
305(b) by States do not represent only those effects caused by toxic pollutants; conventional
pollutants are also included in States' allocations of responsibility.
Pursuant to Section 304(1) of the WQA of 1987, EPA and States develop lists of
facilities that contribute to water quality criterion exceedances for toxic pollutants in receiving
waters, where criterion exceedances are expected to be due entirely or substantially to
discharge from point sources. Of the 888 facilities on the list, 254 are POTWs, 171 of which
have approved pretreatment programs. POTWs were put on the list primarily because of
their metal discharges (see Table 6-6), with 97 POTWs selected because of copper
discharges, 73 for lead discharges, and more than 50 for-mercury, zinc, or cadmium
discharges. Only 10 POTWs were placed on the list for phenols, and six of"fewer facilities
were listed for other toxic organic compounds. .
6.2.3.2 Water Quality Criterion Exceedances
The set of pretreatment POTWs that was used to calculate water quality criterion
exceedances was limited by the availability of data. Table 6-7 presents information on the
numbers of pretreatment POTWs that could be used for the analysis at each step of the
procedure. Of the 2,015 POTWs covered by local pretreatment programs, 995 (less than 50
percent) had the requisite data from PCS, NEEDS, and GAGE to foster this analysis. For
individual pollutants, there were even fewer plants for which adequate data were available.
... ' '' ' "„ ' "' '', , ''!* " ' l
6-26
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Table 6-5. Amount of Assessed Surface Waters Not Fully Meeting Use
Designations in 1988 Because of the Source Listed
Rivers
(thousands of miles [%])!
Agriculture
Municipal (POTWs and CSOs)
Storm Sewers '
Land Disposal
Resource Extraction
Habitat Modification . .
Industrial
Construction
Combined Sewers
Silviculture
79.4
23.4
12.7
6.4
18.8
18.6
12.3
9
5.3
12.4
(55.2)2
(16.3)
(8.8)
(4.4)
(13.0)
(12.9)
(8.5)
(6.3)
(3.7)
(8.6)
Lakes
(millions of acres [%])
1.564
0.405
0.744
0.711
0.113
0.89
0.208
0.088
0.008
0.025
(58.2)
(15.1)
(27.7)
,(26.5)
(4.2)
(33.1)
(7.7)
(3.3)
(0.3)
(0.9)
Estuaries
(thousands of sq miles [%])
0.899
2.571
1.38
. 1328
1.657
0.234
0.588
0.608
0.499
0.077
•(18.6)
(53.1)
(28.5)
(27.4)
(34.2)
(4.8)
(12.1)
(12.5)
(10.3)
(1.6)
1. Percentages are of miles (rivers), acres (lakes), and square miles (estuaries) reported by States as not fully
meeting designated uses, not of total miles, acres, or square miles. '
2. Percentages sum to greater than 100% because some uses may not be met for more than one reason.
Source: EPA (1990a).
6-27
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Table 6-6. Number of POTWs on the 304(1) Short-List of Facilities
Contributing to Water Quality Standards Exceedances
for Toxic Pollutants
Pollutant
Copper
Lead
Mercury
Zinc
Cadmium
Silver
Nickel
Chromium
Phenols*
Chlorofonn
PCBs
Thallium
Dioxin
Beryllium
Selenium
Arsenic
Phenol*
Aldrin
Endosulfan
Heptachlor
Dieldrin
Benzidine
Chlordane
Whole Effluent Toxicity
Number
of POTWs
97
73.
59
57
56
41
23
20
10
6
6
5
5
4
4
.4
3
2
2
2
1
1
1
1
'
•'
"Phenol" is a single chemical compound. "Phenols" include a
variety of chemical compunds closely related to phenol in
terms of chemical structure.
6-28
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Table 6-7. Number of POTWs Included in the Water Quality Criterion
Exceedance Analysis
Category
Pretreatment plants
in PCS
matched with NEEDS
with 7Q10 > 0 in GAGE file
with concentration data in PCS
with units data in PCS
Number of
POTWs
2,015
1,952
1,764
1,404
1,032
995
Percent of
POTWs
100
97
88
70
51
49
It was not possible for EPA to ascertain how representative this analysis is of the ,2,015
'' " ' ' ' ' •
pretreatment POTWs. North Carolina, for example, has an extensive monitoring program for
POTWs (particularly for heavy metals), but no North Carolina POTWs listed data for toxic
pollutants in PCS. Similarly, Ohio requires an annual priority pollutant scan for all of its
POTWs, yet most of these data are not entered into PCS. EPA expects that these and other
omissions may have biased the results of the analysis.
On the other hand, the criterion exceedance analysis is particularly rigorous. It,uses
data from about half of the pretreatment POTWs in the United States and determines
whether each may cause receiving water impacts irrespective of other discharges and
ambient concentrations in receiving waters.
Table 6-8 presents the results of the analysis of water quality criterion exceedances.
Note that of the 995 pretreatment POTWs that reported concentrations for at least one
pollutant, roughly one-third report average or maximum concentrations of eight metals
(copper, cadmium, zinc, chromium, silver, mercury, nickel, and lead), and less than 2 percent
report data on any of the organic priority pollutants or pesticides.
The exceedance data indicate that there is a high probability that pretreatment POTW
discharges of toxic pollutants are causing receiving water impacts. For example, nearly 53
percent of the dischargers that report the concentrations of mercury are calculated to exceed
chronic water quality criteria in the receiving waters. More than 20 percent of,the POTWs
discharging copper, cyanide, cadmium, mercury, PCBs, silver, and lead are calculated to
6-29
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Table 6-8. Number of Water-Quality Criterion Exceedances Expected to
Be Caused by Pretreatment POTW Discharges at Low Flow (7Q10)
Average Concentrations
Pollutant1
Copper5
Cyanide
Cadmium5
Zinc5
PCBs
Chromium (hexavalent)5
Silver5
Mercury5
Arsenic5
Chromium (trivalent)5
Nickel5
Lead5
Iron5
Selenium5
Chloroform
Tetrachloroethylene
Beryllium
DDT
Endrin
Hexachlorocyclohexane
Toluene
Trichloroethylene
Toxaphene
Percent Greater Percent Greater
N2«* Than Acute3 Than Chronic3
273
178
265
277
28
133
113
205
59
71
236
246
29
19
8
5
11
11
11
11
2
4
. 11
23.1
11.8
10.6
8.3
7.1
4.5
3.5
3.4
1.7
1.4
1.3
0.8
28.2
29.8
23.4 -
8.7
25.0
6.8
32.7
52.7
1.7
1.4
1.7
32.9
3.5
Maximum
Concentrations
Percent Greater
N2»4 Than Acute3
343
245
332
346
39
139
141
263
89
79
288
324
44
54
22
21
10
11
11
13
12
12
11
27.4
15.5
15.4
10.1
10.3
4.3
11.4
3.4
3.4
1.3
2.1
1.9
1.9
0.0
0.0
1. Pollutants are all priority pollutants for which more than 10 POTWsreported data in the MCAV or
MCMX field of PCS.
2. N refers to all pretreatment plants in PCS that have effluent data for average concentrations (left columns)
or maximum concentrations (right columns)
3. Percent exceedances are calculated on the observed number of pretreatment POTWs reporting data for a
particular pollutant, not the total number of pretreatment POTWs. . •
4. Exceedances are not calculated when data were available for fewer than 20 POTWs.
5. Metals represent total recoverable metals, not readily bioavailable metals, and thus the percentages of
exceedances may be overestimated.
Source: PCS for POTWs meeting data requirements.in Table 6-7.
6-30
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exceed chronic criteria. Acute criteria for copper, cyanide, and cadmium are exceeded by the
discharges of more than 10 percent of POTWs.
Copper was the pollutant for which EPA calculated exceedances for the highest
percentage of POTWs. The average concentrations and the maximum, concentrations were
estimated to exceed water quality criteria, after dilution by receiving waters, for about 30
percent of the measured discharges. Copper is ubiquitous, often entering POTWs from
drinking-water distribution systems, and is moderately toxic to receiving water biota. (The
acute water quality criterion is 18 micrograms per liter [p.g/1] at 100 mg/l hardness.) Like
most metals, it tends to attach to particles and, thus, partitions to sludge or settles and
remains in sediments if discharged.
Cyanide is a soluble toxic pollutant that typically has a greater effect on vertebrates
(fish) than invertebrates (insects, Crustacea, molluscs). It ranked second in the percentages
of exceedances of water quality criteria. Cyanide is less acutely and chronically toxic than
most of the heavy metals and exerts its toxic effect by attaching to the respiratory pigment
hemoglobin, preventing oxygen transfer and exchange. It is primarily an industrial chemical
used by electroplaters, organic chemicals, and pharmaceutical manufacturers. Cyanide
generally is removed from wastewaters by partitioning to sludge.
Cadmium was-the third-ranked pollutant predicted to exceed water quality criteria.
Average receiving water values of cadmium were estimated to exceed the acute water quality
criterion in more than. 10 percent of the cases. It is a mobile and toxic metal, similar in
toxicity to the pesticides aldrin and dieldrin. Cadmium was responsible for Itai-Itai in Japan,
a malady causing severe rheumatic and myalgic pain. Although cadmium readily sorbs to
sediments and other particles in the water column, it also can become part of soluble organic
compounds and is easily complexed. It is typically used in electroplating and paint
manufacture.
Zinc is a common metal pollutant that generally is discharged from industries, but a
portion also arises from water distribution systems (in some POTWs, this fraction may be
significant). It is commonly incorporated into cosmetic and medicinal preparations because of
its therapeutic value with topical application. With ingestion, it is an emetic (i.e., causes
vomiting). Average receiving water values exceeded acute and chronic water quality criteria
for about 8 percent of the discharges.
6-31
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PCBs are a group of related organic compounds that are toxic, carcinogenic, and very
persistent. Seven percent of POTWs' discharges of PCBs were calculated to cause acute
criterion exceedances and 25 percent to cause chronic criterion exceedances. However, only
28 and 39 POTWs reported average concentrations and maximum concentrations,
respectively. Use of PCBs in transformers as dielectric fluids has caused their widespread
distribution, even though the production of PCBs for domestic use has been banned for more
than 10 years. Current sources of PCBs to POTWs are thought to be ranoff irom land that.-
has been contaminated with PCBs by atmospheric deposition or accident (which may enter
POTWs through combined sewers) or from recyclers involved in transformer recovery. PCBs
,, f ,,!| ' •,''' ' „,!, •. ' ;• ', • , M,,,,;, 'i. „'•.,, r i;, ,!..,•«,' I"1! '., • r iH'i ,"»!|l1Jij'i""l|i"i' '"i,.!,"••"' • '^'^y ,.',i,'.,,'.'-» .,• ''"'JJ ' '•' -"' '"'
are resistant to biological degradation, attach readily and strongly to sediments, and axe
relatively volatile. They are as acutely toxic to aquatic life as the most toxic metals and
cause chloracne in humans at high concentrations.
Chromium is a moderately toxic metal that is commonly used in chrome plating, pigment
manufacturing, and leather tanning. It caused criterion exceedances less than 7 percent of the
time in its hexavalent (more toxic) form.
Silver ranked seventh in the exceedance percentages, exceeding chronic criteria for more
than 30 percent of the reported discharges. Silver is similar in toxicity to mercury and
cadmium and may be removed from POTW wastewaters by partitioning to sludge. Its source
is primarily commercial and industrial, but its economic value means that pollutant recovery is
often practiced at industrial sites prior to discharge to sewers. The high number of
exceedances is due primarily to the low chronic criterion value (6.12 ng/1).
i t • , •",.•''.• • " ' ':••''.''. .'•" '•" '•' ."!''• • :.'':•'> WSOL^ ,•'• '•, i
Mercury, a toxic and mobile metal, had the eighth highest percentage of exceedances,
primarily due to the number of discharges exceeding the chronic water quality criterion, the
chronic criterion is set by the Agency at 0.012 \ig/l to prevent the accumulation of mercury in
edible fish above the Food and Drug Administration Action Level of 1.0 milligrams per
kilogram. The very high bioaccumulation of organic mercury compounds requires this low
criterion. The most common form of organic mercury, methylmercury, is created readily from
inorganic mercury by biological activity in sediments and in biota. It was this form of mercury
that was responsible for Minimata disease, mercury poisoning arising from eating
contaminated fish and shellfish. Mercury is typically discharged from POTWs in its inorganic,
less soluble form.
6-32
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Lead is the only other pollutant to exceed both acute and chronic criteria. In the aquatic
environment, it is one of the least toxic metals (82 ng/1 acute criterion). It enters POTWs
primarily from industrial sources, but may also come from water distribution systems (lead
pipes) in older communities. Previously an additive to gasoline, lead has had widespread
distribution in aquatic environments due to atmospheric deposition and runoff from roads and
highways. In this analysis, average concentrations of lead in receiving waters exceeded
chronic criteria more than 30 percent of the time.
The exceedance data generally appear to be consistent with the data reported by the
States in their 305(b) reports." The high likelihood of a criterion exceedance caused by a
POTW discharge, as calculated from discharge data, indicates that water quality below
POTW outfalls may often be impaired. The 305(b) data indicate that over 23,000 miles of
rivers are reported to be affected adversely by POTW discharges—about 1.5 river miles for
each POTW listed in either PCS or NEEDS. Both of these essentially independent findings
indicate significant POTW impacts, although the 305(b) data do not indicate specific toxic
effects! Although neither data source establishes a link between POTW impacts and me
presence of a pretreatment program, both indicate that additional controls over toxic
discharges from POTWs are warranted.
6.2.3.3 Toxicity
Although PCS has over 50 codes for incorporating whole effluent toxicity test data into
the data base, only i 1 codes have more than four observations on which to base an analysis.
These codes were for the two most common test organisms used in.the NPDES program
(Ceriodaphnia sp and Pimephales promelas) for static and static renewal toxicity tests.
POTWs' data presented in Table 6-9 (representing 1987, 1988, and 1989) indicate, as
did the individual toxic pollutant data (fable 6-8), that POTW discharges have a strong
likelihood of causing criterion exceedances in receiving waters. In acute tests, about 17
percent of the static tests for Ceriodaphnia and 17 percent of the static renewal tests for
Pimephales would result in receiving water concentrations that exceeded EPA's CMC.
Chronic tests indicated an even higher percentage of exceedances, with 30.4 percent of
Ceriodaphnia and 14.3 percent of Pimephales tests resulting in receiving water
concentrations that would exceed the CCC. Finally, the pass/fail results (results that
incorporate receiving water standards implicitly) indicated that 70 percent or more of all tests
failed. (The pass/fail criteria are not known for these tests. It is assumed that no observed
effect [or only a small percentage effect] was required to pass.)
. ' 6-33 ' _'".'•
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Table 6-9. Criterion Exceedances Indicated by Toxicity Test Results on
POTW Effluents
Species
Acute
Ceriodaphnia
Pimephales
Ceriodaphnia
Pimephales
Chronic
Ceriodaphnia
Pimephales
Pass/Fail
Ceriodaphnia
Pimephales
Endpoint
LC5o .
LCso
LC5o
LC5o
NOEL
NOEL
P/F
P/F
Test
;.
STAT48hr
STAT48hr
STATRE 96 hr
STATRE 96 hr
"
STATRE 7 day
STATRE 7 day
STATRE 7 day
STATRE 7 day
Number
of Plants
23
18
7
18
23
21
37
37
Percent of
Test Failures1
'. ..-••• •
17.4
5.6
0.0
16.7
30.4
14.3
73.3
91.3
1. Total number of test results, divided by the number of tests that failed, multiplied by 100.
Key:
STAT = Static test
STATRE = Static renewal test
LCso = Lethal concentration for 50 percent of organisms tested
NOEL = No observable effect level for organisms tested
P/F = Pass/fail
Source: PCS.
6-34
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It is difficult to interpret the significance of these data, or how well they represent
pretreatment POTWs or the entire POTW population. These results all come from POTWs
in a single EPA Region. The tests may have been conducted as part of Toxicity Identification
Evaluations, in which case they would have been performed only at POTWs known to have
toxic discharges. EPA did not determine whether a link exists between an exceedance of a
toxicity criterion and the presence or absence of a pretreatment program.
6.3 GROUND-WATER EFFECTS
This section discusses the sources and adequacy of data concerning the effects on
ground water of toxic releases from POTWs, a methodology for determining effects, and the
results of employing the methodology.
6.3.1 Sources and Adequacy of Data
POTWs1 primary impacts on ground water come from the treatment of sewage in
lagoons and from disposal of sewage sludge. There are 5,476 municipal lagoons in the United
States (from NEEDS, as quoted in EPA Lagoon Study). The Agency does not currently
require the monitoring of impacts from these two activities on ground water, so there are only
limited data on the environmental impacts of POTW operations on ground water. A study of
the impacts of lagoons and the ultimate risk to human health was reported to Congress in
1987 (EPA, 1987). The data that are contained in this study are limited to relatively few
lagoons, but the distribution of the lagoons analyzed was selected to be representative of
lagoons nationwide. Although the data do not represent a large portion of the lagoons that
may have impacts, they are suggestive of the kinds of impacts that might be expected.
Subsection 6.3.3 discusses the results.
The major releases to ground water from sludge occur during or after disposal. But once
pollutants get to sludge, there is no large-scale model available to determine their ultimate
fate. On the national scale, the greatest amount of sewage sludge is disposed of by land
application (2.3 million dry metric tons per year), followed by co-disposal landfills (1.1 million
dry metric tons), and incineration (760,000 dry metric tons, see Table 6-10). The remaining
disposal practices, including ocean disposal, surface disposal, and monofills, account for an
additional 1.7 million dry tons per year. Thus, the great majority of sludge disposal practices
have at least the potential to contaminate ground water, but few data indicate the size of that
potential.
6-35
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Table 6-10. Numbers of POTWs Using Specific Sludge Disposal Practice
as Primary Sludge Disposal Practice and Amounts of Sludge Disposed of
Using Each Practice
Disoosal Method
Co-Disposal Landfills
Incineration
Land Application
Distribution and Marketing
Ocean Disposal2
Other
Surface Disposal
Monofills
Total
Numbers
of POTWs
1,851
294
3,542
308
25
1,526
3,147
203
10,896
Percent
of POTWs
17
2.7
32.5
2.8
0.2
14
28.9
1.9
100.0
Total Percent of
Amount Total Amount
of Sludge1 of Sludge
1,124.3
759.8
2,336.7
321.3
265.2
107.9
512.3
108.8
5,536.3.
20
14
42
6
5
2
9
2
100.0
1. Total amount of sludge is in thousand dry metric tons, total is extrapolated to all POTWs with secondary
treatment or better. , , , ' : ..". ... ' ""'„'„ "/',"'!"! "'„ .'.".".".".'.I." I'..'".
2. Based upon number of existing permits.
ii, „'", ' , ; " , .",• • * , •, ' ,' " ' i i ,; ,; ' Hi, •, "'•,, 'I; Bi'i'l ii. v'l • , !•' ' •,' "I "'. "r: I1''*,!,':'/', • ','"! I i1',!',' ''! i
Source: EPA (1990b).
In support of the proposed sewage sludge regulations (40 CFR Part 503), the Agency
gathered and analyzed a large amount of existing information on the .environmental effects of
sewage sludge and disposal. EPA used two main sources of information on sludge quality
and management: the 40-POTW Study and the Association of Municipal Sewerage Agencies
sludge study. These studies, however, are now somewhat outdated and apply to a limited
number of POTWs. The Agency, therefore, conducted the National Sewage Sludge Survey,
beginning in August ,1988, in which questionnaires were" sent""to 479f pofWs seeking
information about sludge quality and disposal practices; sludge samples at 208 POTWs were
analyzed for a wide range of toxic pollutants. The results of this survey were used for this
analysis.
6.33 Methodologies for Determining Impacts
The Lagoon Study (EPA, 1987) determined the number ana"size of municipal lagoons,
the types and quantities of waste contained in those lagoons, and the extent to which the
waste has been or may be released from lagoons and has contaminated or may contaminate
6-36
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ground water. EPA initiated a limited sampling program and used the results in EPACMS, a
model that evaluates the migration of. pollutants to selected points in underlying aquifers.
The model was used to determine whether acceptable ground-water concentrations would be
exceeded for lagoons with typical concentrations for different representative geologic
conditions. The results of this study are summarized in the following subsection.
Because the Part 503 technical standards for sludge use and disposal have not yet been
finalized, EPA could not compare the NSSS data with the Fart 503 Standards to determine
potential impacts of sludge on ground water.
. . " i ' • * •".'.. •••-''•,.-•
6.3.3 Results /
6.3.3.1 Lagoon Study
The Lagoon Study (EPA, 1987) sampled 14 wastewater treatment lagoons and
determined which would exceed either Safe Drinking Water Act Maximum Contaminant
Levels (MCLs) for drinking water or Risk Specific Doses (RSDs) for either a 10'5 or 10'6
incremental cancer risk for the compound selected. Based on a sampling for the 126 priority
pollutants, four compounds were found to exceed levels necessary to maintain compliance
with MCL levels in aquifers: benzene, 1,2-dichloroethylene, arsenic, and selenium. Of these
compounds, selenium was found to exceed the MCL most frequently (for 43 percent of the
samples). A significantly greater number of compounds were found to exceed RSJDs'i The
following compounds were found to exceed RSDs for more than 20 percent (3) of the samples:
2,4,6-trichiorophenol, benzidine, bis(2-ethylhexyl) phthalate, 2,4-dinitrotoluene, and
hexachlorobenzene. Other compounds that exceeded RSDs at least twice included
hexachloroethane, n-nitrosodiphenylamine, and methylene chloride.
These results, however, are not necessarily representative of the full effects of the
lagoon treatment process. In the conclusions of the study, the Agency indicated that there
was a low potential for ground-water contamination from municipal wastewater lagoons, but
that lagoons with industrial discharges may be potential sources of ground-water
contamination. Similarly, the Agency concluded that the human health risks associated with
ground-water contamination from wastewater treatment lagoons receiving only domestic
wastes are generally low, but that lagoons with significant industrial discharges pose a
potential risk to human health.
6-37
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6.3.3.2 Sludge Disposal
The national pollutant concentration estimates in Table 6-11 were taken from the Notice
of Availability of information and data from the National Sewage Sludge Survey (NSSS).
.This survey was conducted to support the development vof the Part 503 regulations. The
pollutant concentrations in Table 6-11 are estimates for the distribution among POTWs of
pollutant concentrations in dry weight sewage sludge that is ready for disposal and that is
generated by secondary or better treatment of wastewater.
The Part 503 standards proposed in 54 PR 5746 (see Appendix C) are currently being
reviewed, and the final standards may be higher or lower than those proposed. As a result of
information and comments provided by scientific peer review panels' and other interested
parties, as well as the findings of the NSSS, EPA is considering revising the elements of the
proposed Part 503 standards pertaining to domestic septage, emissions of organic pollutants
,j ' ' ' ,' •' . i, •;„' „!', i ",i f , ••' ,,, , i,,i| ] ?• , jii;'1,,!"',,',',i, 'i,iiii;i,.i'i:,,i!!!,K:,i,, 1.1,1" jy;,, h i.v'j i, ;., ,\iHI ' ii,1
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The National Emissions Data System (NEDS) is an EPA data base containing data
entered by States on facilities that emit more than 100 tons per year of any Clean Air Act
criteria pollutant, which include particuiates, sulfur dioxide^ carbon monoxide, nitrogen oxides,
ozone/VOCs, and lead. Only 27 POTWs/including only l2 with sludgeIncinerators, are
represented (by Standard Industrial classification^in NEDS: Of ^se^'werePofWsthat
could be located in either PCS or NEEDS.
The best information on air emissions from sludge incinerators available to the Agency
was developed in support of the proposed sludge technical standards (40 CFR Part 503).
These data were published in the Incineration of Sewage Sludge Technical Support Document
(EPA, 1988) and represents measurement of emissions from sludge incinerators under
controlled conditions. These data were used in the analysis described below.
Emissions of toxic VOCs from POTWs are even more poorly studied than incinerator
emissions. Most studies and regulation of VQC emissions are based on modeling, not
monitoring, and it is difficult to obtain and interpret data on the actual emissions of volatile
materials from POTWs.
In 1990, EPA cosponsored a workshop with the Water Pollution Control Federation on
emissions of air toxics from POTWs. The draft proceedings of the workshop (WPCF/EPA,
1990) indicated that the compounds of greatest concern are the potentially hazardous air
pollutants (PHAPs): trichloroethylene, tetrachloroethylene, methylene chloride, acrylonitrile,
and carbon tetrachloride, all of which are VOCs. They also> "indicate that the Increase iri
cancer deaths per year caused by emission from POTWs of these chemicals is less than lJ:
This implies that the effects on the general public of VOC emissions are essentially
negligible.
This does not imply that the actual quantities of VOds emitted from POTWs are
negligible, however. The DSS indicated that 0.1 percent of the mass of national emissions of
VOCs may come from POTWs, primarily from the industrial contnbutibns to POTWs. Noll
and DePaul (1987) estimated that POTWs operated by me Metropolitan Sanitary District of
Greater Chicago contributed about 0.1 percent of the VOC emissions in Cook County, Illinois,
amounting to annual contributions of tens of thousands of metric tons of VOCs nationwide.
The low risk from volatile air emissions appears to be borne out by available information
on POTW worker health and safety. Most studies of POTW worker health focus on the
6-40
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effects of infectious agents or toxins generated by microorganisms found in wastewater or
sludge. A body of literature addresses confined-space accidents, which involve employee
exposure to gases, such as carbon dioxide, methane, or hydrogen sulfide, while working in
collection systems or treatment: plants.
A relatively small portion of the above literature directly addresses POTW worker
exposure to hazardous materials. Most of this literature involves studies conducted at single
plants (Elia et al., 1983) or small groups of plants (Scarlett-Kranz et al., 1986; Pellizari and
Little, 1980). Occupational Safety and Health Administration records documenting
inspections and testing at work sites usually do not address POTW employees because me
Agency's jurisdiction does not extend to municipal workers.
6.4.2 Methodologies for Determining Impacts
Because so few data exist on the environmental impacts of gaseous emissions from
POTWs; EPA did not conduct any specific analyses to determine impacts. Instead, the
following sections summarize available studies on the nature of incinerator emissions and the
effects of VOC emissions on POTW workers.
6.4.3 Results
This subsection summarizes information used for the development of the Part 50.3
sewage sludge technical standards. It also describes the results of a literature search on
worker health and safety at POTWs.
6.4.3.1 Sludge Incinerator Emissions
While developing the proposed sludge technical standards (40 CFR Part 503), the
Agency collected extensive information on the emission characteristics of sewage sludge
incinerators and sewage sludges. Table 6-12 presents information on the average
concentrations of metals in sewage sludge, the 10th percentile removal efficiencies as
calculated from emission and sludge feed data, the relative potency of the pollutant for
causing cancer in exposed individuals (a higher number indicates a higher incidence of cancer
per unit of dose or concentration), and the relative risk posed by emission of the pollutant
(calculated by dividing the emission by the potency). In this analysis, the higher the relative
risk number, the more cancers are likely to be caused by the pollutant. ;
Although Table 6-12 indicates a removal efficiency for metals in sewage sludges, it is
important to recognize that when the metals are removed, they become part of some other
6-41
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Table 6-12. Relative Emissions of Pollutants Per Unit of Incinerated
Sludge and Relative Cancer Risks Posed by Emission
Pollutant
Zinc
Lead
Chromium
Cadmium
Nickel
Mercury
Arsenic
Selenium
Beryllium
Percent
Detected
100
80
91
69
66
63
80
65
10th Percentile Emission Per
Mean Removal Metric Ton Relative
Concentration Efficiency of Sludge qi*l Risk
1,202
134.4
119
6.94
42.7
5.2
9.9
5.2
94.17
66.73
96.12
65.15
95.00
79.842
95.52
99.44
99.98
70.1
44.7
/
.'
4.62 41 1 0.11 3
2.42 6.1 0.40
2.14 1.05 2.03
1.05
0.444 15 0.03
0.0291
8.4
1. Relative potency for causing cancer in exposed individuals (higher numbers indicate higher cancer incidence
per unit dose/concentration).
2. The maximum value for percentage mercury removal.
3. Emissions per metric ton of sludge divided by ql*.
Sources: EPA (1990b).
EPA (1988).
6-42
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wastestream (scrubber water or ash). They are not destroyed during incineration and
continue to have the potential to cause environmental effects.
The data in Table 6-12 are incomplete for several metals. Mercury and beryllium are
subject to national air quality standards for toxic pollutants, and emissions of these pollutants
are regulated under State laws (see Appendix C-3). Emission limits are not set on beryllium
and mercury based on their cancerrinducing potency. Therefore, data on these chemicals are
not comparable to other data presented. Similarly, sludge standards for lead are based on
toxicological effects other than cancer that may be caused by lead in blood. Lead is, therefore,
not comparable strictly to the other pollutants in this table. The most commonly emitted
metal—zinc—is not considered carcinogenic by EPA's Carcinogen Assessment Group and
does not have other significant toxicological effects. Therefore, no risks are calculated for
zinc.
The relative risks posed by nickel emissions are five times those of cadmium. However,
this assessment, according to EPA's Incineration of Sewage Sludge Technical Support
Document (1988), is based on a particularly carcinogenic nickel compound that may not be
representative of the compounds expected from the incineration of sewage sludge, EPA is
reviewing these data to determine if alternative values might be more appropriate.
6.4.3.2 Worker Health and Safety
The Water Pollution Control Federation (WPCF) has conducted a safety survey of
employees at POTWs annually since 1967. However, the data collected in the survey do not
address directly the issue of injuries due to industrial .discharges of toxic pollutants, partially
because the data are limited to "disabling injuries" resulting in 1 or more los't days from
work. Another limitation in using these data to identify injuries related to industrial effluents
is the absence of the most common symptoms of toxic inhalation (nausea, headache,
dizziness) from the list of potential responses. The types of injuries reported to WPCF are
only a subset of the injuries that are potentially traceable to .industrial effluents. Of the 2,414
disabling injuries reported, 2.4 percent (58) involved respiratory injuries, 5.1 percent (123)
involved irritation (from exposure to chemicals), and 1.6 percent (39) involved chemical
burns. ' ;
Respiratory injuries in the WPCF survey data include incidents involving asphyxiants
commonly encountered in wastewater treatment. Many of the injuries reported are unlikely
to be attributable directly to toxic pollutants. The types of asphyxiants typically involved
1 . - • '
6-43
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(carbon dioxide or hydrogen sulfide) rarely are caused directly by industrial effluents.
However, several examples point out that this may not always be the case. One example
(Pederson and Simonsen, 1982, cited in Clark et al., 1984) involves the 1982 death of two
workers who were overcome by dissolved carbon dioxide released from influent wastewater.
This release was later traced to an industrial discharge.
.' , ''.''.I ',' ' ' ' , ' '• I |l
A literature review identified incidents of POTWworker injuries due to materials
originating in industrial discharges. Table 6-13 summarizes examples of incidents that have
occurred since 1977. Incidents of fatalities from asphyxiants commonly occurring in
wastewater collection and treatment systems (hydrogen sulfide or carbon dioxide) have been
excluded from this table; as noted, injuries from these causes are poorly correlated with
industrial discharges.
The most common incidents involve VOCs. Workers are more often injured than killed
by exposure to contaminants. Injuries most often reported were nausea, headache,
dizziness, and respiratory distress.
Exposure to contaminants usually occurs in the collection system, in confined spaces at
POTWs, or near the headworks of the plant (influent weir, bar screens, grit chamber). It may
be relevant to note that all but 1 of the nearly 30 incidents involved two or more workers. In
"."'!. ' , ' " '"' ', /" ' • ' „" "'I '„'"*• i III I
only one incident was a single worker injured (a case involving a rash caused by direct
contact with wastewater).
Three other studies provide additional evidence of POTW worker injuries due to
industrial discharges. A 1984 study of 14 POTWs in New York State found workers to be
12.9 times more likely to test positive for urinary mutagens than similar workers at drinking
water plants. The same workers also reported diarrhea, blurred vision, and headaches more
often than their counterparts. Research analyzing death certificates from former POTW
workers in the Chicago, Illinois, area (Clark et al., 1984) revealed that the proportion of
workers with leukemia was almost twice the expected rates. For another relatively rare
cause of death, esophageal cancer, the rate among these workers was also nearly twice the
national rate.
6.5 FINDINGS ' ^ " " .' "''.!','".".!.' '.*lr!..",.',' ' '!! V.'!v '..'., ;„,,'
This chapter addresses the issue of the adequacy of data available to determine the
environmental impact of toxic pollutant discharges from POTWs.
6-44
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The first major finding is that few data currently exist on which to base a true evaluation
of environmental impacts due to discharges of toxic pollutants by POTWs. Existing national
data bases are limited in scope and completeness, and often are not quality controlled
sufficiently for rigorous analysis. Other studies and data collection efforts are too fragmented
to contribute to a consistent and reasoned view of impacts caused by toxic discharges from
POTWs.
About half of all pretreatment POTWs had data in national data bases that could be
used to determine the environmental effects of their discharges to receiving waters. The
great majority of plants with data had information in national data bases for only one or two
toxic pollutants. However, POTWs may retain environmental effects data that are not
reported to approval authorities or incorporated into national data bases. Recent revisions to
the General Pretreatment Regulations, which require pretreatment and greater-than-1-mgd
POTWs to report whole-effluent toxicity testing results to approval authorities with thek
permit applications, will improve POTW and approval authority knowledge of POTWs' toxic
effects on receiving waters.
Of equal if not greater importance, drinking water, surface water, and sludge standards
for assessing impacts are in existence for comparatively few pollutants. This makes
assessment of POTW impacts even more difficult.
Second, EPA finds that despite the lack of consistent monitoring data, receiving water
impacts are likely due to the discharge of toxic pollutants from POTWs (although the relative
role of pretreatment POTWs in causing such impacts could not be ascertained). Water
, quality criterion exceedances were predicted for large percentages of reporting POTWs. The
fact that PCS reports a much lower percentage of POTWs as not in compliance because of
toxic discharges points out-the need for States to continue developing water quality
standards and the need for coordination at both the State and Federal level regarding the
reporting and management of exceedances data. '
This leads to the third major finding—available standards against which POTW
discharges are judged (and limited) are developed inconsistently across States for each of the
media affected by POTW operation (air, water, and sludge). Significant nationwide
reductions in toxic discharges can be expected once appropriate standards for receiving media
are developed and implemented consistently among States. Water quality standards for toxic
pollutants currently are being developed by EPA fdr those States that do not have
'' ' * . 6-47 .
-------
appropriate standards and are not developing them. Air standards are limited to mercury and
beryllium; no effective standards exist for VOCs, and none are being developed. Sludge
standards are in the process of being developed.
There are more State standards and more data for toxic metals than for toxic organic
compounds. States are likely to have targeted metals for their standards development efforts
because they found metals more pervasive as well as easier and cheaper to analyze.
•: !,r ,,.. ,' 1|l:ll"P!i. f! in
Finally, this chapter and those preceding it point out that.the only feasible method of
reducing the release of toxic pollutants from POTWs is to reduce their input to POTWs—
either through pretreatment or through pollution prevention activities at the source. Unless
toxic pollutants are readily and quickly degraded in a POTW, they are either discharged in
effluent, enter into sludge, or volatilize; Pollutants that are reinoved from/the wastewatef
through volatilization or partitioning to sludge are only changing the exposure pathway by
which they enter the environment. The release of persistent, toxic compounds into the
environment, no matter what the receiving medium, only contributes to a problem that must
eventually be addressed.
During this study, EPA found that the major environmental effects of POTW operation
(to the extent that the effects could be evaluated) appear to occur in the aquatic environment.
Information on worker health and safety, as well as the small estimate of increased cancer
deaths nationwide, suggests that VOC emissions from POTWs are not as serious a problem
as aquatic discharges. At this time, there are insufficient data on which to base any
jhii . , • ,• , ' ;, „" "' i'; ' , "', ° • "'' ''" Hi1 • •' '•;;,; i/1 ' UN
conclusions about sludge disposal. EPA's ongoing rule-making activities to develop
technical sludge criteria should enable the Agency to fill the relative absence of data on this
exposure pathway.
6-48
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REFERENCES
Centers for Disease Control. 1987. Registry of Toxic Effects of Chemical Substances.
National Institute for Occupational Safety and Health Publication #87-114
' Clark, C.S., H.S. Bjornson, CC. Linnemann, Jr., and P.S. Castide. 1984. Evaluation of
Health Risks Associated With Wastewater Treatment and Sludge Composting.
Cincinnati: Institute of Environmental Health, University of Cincinnati Medical Center.
Clark, C.S. 1986. Health Effects Associated With Wastewater Treatment and Disposal.
Journal of the Water Pollution Control Federation 58(6):539-43.
Elia, V.J., C.S. Clark, V.A. Majeti, P.S. Gartside, T. MacDonald, N. Richdale, C.R. Meyer,
G.L. Van Meer, and K. Hunninen. 1983. Hazardous Chemical Exposure at a Municipal
Wastewater Treatment Plant. Environmental Research 32:11.
International Joint Commission. 1989. A Review of Pretreatment Programs in the Great
Lakes Basin.
Johnson, P., and J. Horan. 1982. Health Hazard Evaluation: Metropolitan Sewer District.
Cincinnati: Metropolitan Sewer District.
Kominsky, J.R., C.L. Wisseman, and D.L. Morse. 1980. Hexachlorocyclopentadiene
Contamination of a Municipal Wastewater Treatment Plant. Cincinnati: NIOSH.
Kraut, A., R. Litis, M. Marcus, J.A. Valciukas, M.S. Wolff, and PJ. Landrigan. 1988.
Neurotoxic Effects of Solvent Exposure on Sewage Treatment Workers. Archives of
Environmental Health 43(4):263.
Lucas, A.D. 1982. Health Hazard Evaluation Report. Number HETA-81-240-1031,
Metropolitan Sewer District. Cincinnati: National Institute for Occupational Safety and
Health.
McGlothin, J.D.,-and J.E. Cone. 1981. Health Hazard Evaluation. Cincinnati: Metropolitan
Sewer District. NTIS: PB83-127399.
Morgan, R.W., L. Kheifets, D.L. Obrinsky, M.D. Whorton, and D.E, Foliart (M.D.). 1984.
Fetal Loss and Work in a Waste Water Treatment Plant. American Journal of Public
Health 74(5):499.
Nethercott, J.R., and D.L. Holness. 1988. Health Status of a Group,of Sewage Treatment
Workers in Toronto, Canada. American Industrial Hygiene Association Journal
'•• 49(7):346-50.
Noll, K.E., and RT. DePaul. 1987. Emissions of Volatile Organic Compounds From the
Sewage Treatment Facilities of the Metropolitan Sanitary District of Greater Chicago.
Chicago: Metropolitan Water Reclamation District of Greater Chicago.
Pellizzari, E.D., and L. Little. 1980. Collection and Analysis of Purgeable Organics Emitted
From Wastewater Treatment Plants. U.S. EPA Office of Research Development.
EPA-600/2-80.-017.
Salisbury, S., P. Drotman, and P. Baxter. 1982. Health Hazard Evaluation Report Number
TA-79-040-1033. Big Creek Water Pollution Control Plant, Roswell, Georgia.
Cincinnati": NIOSH.
6-49
-------
Scarlett-Kranz, J.M., J.G. Babish, D. Strickland, R.M. Goodrich, and DJ. Lisk. 1986. Urinary
Mutagens in Municipal Sewage Workers and Water Treatment Workers. American
Journal of Epidemiology 124(1):884.
Science Applications International Corporation. 1985. "AMSA Survey Results. Prepared for'
the U.S. EPA Office of Water Regulations and Standards. .
Toz2i, T. 1990. POTW. Personal communication. Bergen County, NJ.
U S Environmental Protection Agency. 1990a. National Water Quality Inventory 1988
Report to Congress. Washington, DC: Office of Water Regulations and Standards.
'EPA/440/4-90-003. .
U S EPA. 1990b. Technical Support Documentation for Part I of the National Sewage
Sludge Survey Notice of Availability. Washington, DC: Analysis and Evaluation
Division.
U S. EPA. 1989. Results of the Evaluation of Ground-water Impacts of Sewer Exfiltration.
' Prepared by Engineering Science under Contract No. 68-03-3431 to Office of Water.
U S EPA. 1988. Incineration of Sewage Sludge Technical Support Document. Washington,
" "DC: Office of Water. NTIS: PB89-136592.
U.S. EPA. 1987 Report to Congress: Municipal Wastewater Lagoon Study. Washington,
DC: Office of Municipal Pollution Control.
U.S. EPA. 1986a (1990 update). Quality Criteria for Water., Washington, DC: Office of
Water Regulations and Standards. EPA/440/5-86-OQ1.
U S EPA. 1986b Report to Congress on the Discharge of Hazardous Wastes to Publicly
Owned Treatment Works. Washington, DC: Office of Water Regulations and
Standards. 530-SW-86-004.
U.S. EPA. 1985^ Technical Support Document for Water Quality-Based Toxics Control.
Washington, DC: Office of Water.
U.S. EPA. 1979. Water-Related Environmental '"Fate' of 129 Priority Pollutants:
Washington^ DC: Office of Water Planning and Standards. EPA/440/4-79-029-a.
Water Pollution Control Federation/EPA. 1990. Executive Summary of Conference
Proceedings: Air Toxic Emissions from POTWs.
1:1! ''i-'SFi >•,'„'.'". Hi*!"!
6-50
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7. EFFECTIVENESS OF THE NATIONAL PRETREATMENT PROGRAM
This chapter evaluates the extent to which the National Pretreatment Program, as
currently conceived and implemented, has been successful in achieving the objectives of
the Clean Water Act (CWA). The discussion assesses the program's effectiveness in
two ways: by focusing on the process and procedures associated with implementing the
program and by addressing the effectiveness of the program in reducing or preventing toxic
pollutant discharges to publicly owned treatment works (POTWs). In evaluating the
strengths and weaknesses of the current program, this chapter supports the identification
and consideration of alternative regulatory strategies given in Chapter 8. .
. • . -• T ' ' '
A comprehensive evaluation of the-National Pretreatment Program necessitates both
an understanding and an analysis of how the program is currently being implemented.
Section 7.1 examines the current scope and coverage of the program; This section
evaluates whether the program covers those POTWs whose size or industrial discharges
make them likely to receive toxic pollutants in quantities that could affect treatment plant
operations or the environment. It also examines the extent to which the program
addresses those industries known to discharge toxic pollutants and the pollutants being
discharged. Section 7.2 evaluates the effectiveness with which POTWs have implemented
the requirements of the National Pretreatment Program. Because successful program
implementation is key to achieving the CWA's objectives, this evaluation provides an
indirect measure of overall program effectiveness. Section 7.3 examines the effectiveness
of POTWs in achieving the environmental objectives of the program and the CWA.
Section 7.4 concludes the chapter by summarizing major findings. .
7.1 ASSESSMENT OF THE SCOPE OF THE NATIONAL PRETREATMENT PROGRAM
This section assesses the coverage of POTWs, industrial dischargers, and pollutants
by the National Pretreatment Program.
7.1.1 POTWs Covered by Pretreatment Programs
One critical measure of the National Pretreatment Program's effectiveness is the
extent to which the program regulates the POTWs that should be regulated because of
their size, the nature of their industrial community, or the impact of their discharge on the
environment. This subsection examines the extent to which the program currently covers
such POTWs. Although EPA believes that most of the POTWs that should be regulated
are already subject to pretreatment requirements, some POTWs should be evaluated for
7-1
-------
the need to develop an approved pretreatment program because of, the nature of their
industrial discharges.
The General Pretreatment Regulations (40 CFR 403.8) require the following POTWs
to develop local pretreatment programs: .
• POTWs with a total design flow greater than 5 million gallons per day (mgd) that
receive discharges from industrial users that cause pass through or interference, or
are otherwise subject to pretreatment standards, unless the State exercises its
option to assume local responsibilities under 40 CFR 403.10(e)
• POTWs with a design flow of 5 mgd or less if tbe'nature'oFmeir industrial influent,
treatment plant upsets, violations of POTW permit limits, contamination of
municipal sludge, or other circumstances so warrant in order to prevent
interference or pass through.
Within this regulatory framework, some U.S. Environmental Protection Agency
(EPA) Regions and States have established specific criteria for the development of local
pretreatment programs. North Carolina, for example, requires any POTW, regardless of
its size, that receives discharges from a categorical or other significant industrial user to
develop and implement a program. Wisconsin, on the other hand, does not require POTWs
with flows less than 5 mgd that have categorical industries to develop local programs;
rather, the State itself regulates categorical industries at such POTWs.
By early 1990, 1,442 local pretreatment programs, covering 2,015 individual treatment
plants, had been approved by EPA Regions and States. In addition, the "403.lO(e)
States" of Alabama, Connecticut, Mississippi, Nebraska, and Vermont (where
pretreatment requirements are implemented by States rather than local POTWs) were
regulating industrial discharges to approximately 314 treatment plants. An additional 100
local programs, covering 113 treatment plants, were under development in response to
EPA Region and State requirements.
7.1.1.1 Relationship Between POTW Size and Program Coverage
EPA found that most large POTWs are covered by the National Pretreatment
" . '! -'ii •.!'•,' • ' " „ ' i1' > ", I1' •• ' ,!'':„'" " I'.' ,. • , , '' II ' I II I I I ' ' I I III I
Program. Although only 10 percent of the Nation's POTWs are subject to the program,
these POTWs provide more than 82: percent of the Nation's municipal wastewater
treatment capacity. Of the nearly 1,000 treatment plants with design flows exceeding
5 mgd, 893 (89 percent) are currently covered by local or State-run programs or are now in
7-2 ,
-------
the process of developing a local program. The remaining 11 percent (105 POTWs)
receive only small industrial contributions.
7.1.1 2 Relationship Between Industrial Contributions and Program Coverage
Most POTWs that receive significant quantities of their wastewater from industrial
sources are covered by the National Pretreatment Program. Table 7-1 lists industrial
contributions to pretreatment and nonpretreatment POTWs, based on flow data reported in
the 1988 NEEDS survey.1 The table shows that more than half of the pretreatment
POTWs receive at least 5 percent industrial flow. It also indicates that a substantial
portion of POTWs not covered by an approved pretreatment program (nearly 86 percent)
does not receive any industrial discharges. The table also shows that 147 treatment
plants, which are reported to receive more than 50 percent of their flow from commercial
and industrial sources, are not covered by either a local or a State-run (403.10[e] State)
pretreatment program. These tend to be small treatment plants, with an average design
flow of about 1 mgd. (In areas where industrial users [lUs] discharge to POTWs that do
not have an approved pretreatrnent program, it is the responsibility of either the approved
State or EPA Region to regulate the IQ directly to ensure compliance with all applicable
pretreatment requirements.)
In addition, the POTWs that receive the largest amounts of toxic chemicals are
covered by the pretreatment program. As described in Chapter 3, EPA's Toxic Release
Inventory (TRI) provides information on the amounts of specific toxic chemicals that are
estimated to be discharged to POTWs by certain types of industrial facilities. Table 7-1
lists those POTWs reported to have received over 1 million pounds of toxic chemicals in
1988 Of the 73 POTWs listed in Table 7-2, 65 (covering a total of 154 treatment plants)
are covered by local (64 programs, 153 plants) or State-run (1 plant) programs; another 3
(covering 3 plants) are currently required to develop local programs. Altogether, the 153
treatment plants operated by the 64 approved local programs received two-thirds (460
million pounds) of the nearly 690 million pounds of toxic chemicals reported to have been
discharged to all treatment plants. Five POTWs, which together received 15,400,000
pounds (2.2 percent of TRI-reported discharges), do not have pretreatment programs and
may not be required to do so.
• 1. NEEDS reports industrial flow (including flow for noncategorical industries) and
POTW design flow based on POTW self-reporting.
7-3
-------
Table 7-1. Industrial Discharges to Pretreatment and Other POTWs
Percent of Total
Treatment Plant
Flow Reported
as Being
Industrial Flow3
0
0<-^5
5< - £10
10< - £25
25< - £50
>50
Total
Pretreatment POTWs1
Treatment Plants
Number
674
216
204
499
363
142
2,098
Percentage
32.1
10.3
9.7
23.8
17.3
6.8
100.0
Average Daily
Flow Rate per
Treatment
Plant (mgd)
4.3
11.7
13.6
17.1
12.8
6.3
10.6
Nonpretreatment POTWs2
Treatment Plants
Number
8,645
252
263
513
257
148
10,078
Percentage
85.8
2.5
2.6
5.1
2.5
1.5
100.0
Average Daily
Flow Rate per
Treatment
Plant (mgd)
0.32
1.31
1.10
1.02
0.93
1.2
0.43
1. POTWs covered by approved local pretreatment programs, POTWs with local programs under development, and
POTWs in Alabama, Connecticut, Mississippi, Nebraska, and Vermont with industrial users regulated by the States.
2. All other POTWs.
3. Includes categorical and noncategorical industries. .
Source: NEEDS '88 for design flow information (from POTW self-reporting); POTWs represented are those in both
NEEDS '88 and PCS with design flow information.
7-4
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Table 7-2. Pretreatment Status of POTWs Receiving the Largest
Amounts of Toxic Chemicals, 1988
State
AZ
CA
CO
CT
DE
FL
GA
IA
IL
IN
KS
KY
LA
MA
MD
ME
MI
MN
MO
*
NC
NJ
Pretreatment
Status
L
L
L
L
L
S
L
R
R
L
L .
L
L
L
L
R
L
L
L
L
L
• — '
L
L
L
L
—
L
. —
L
L
L
L- ,
L
L
L
L
L
L
L
Number : Estimated Million
of Plants POTW* Pounds Per Year**
1
2
4
11
1
1
1
1
1
1
3
1
1
7
1
1
1
2
1
5
9
1
1
1
2
1
1
1
1
1
1
1
2
11
1
1
15
2
2
1
Mesa
Phoenix
Los Angeles (city)
Los Angeles County S.D.
Sterling
Naugatuck
Wilmington
Bay County (Panama City)
Port St Joe
Dalton
Macon/Bibb County (Macon)
Cedar Rapids
Sioux City
Chicago MSD
Sauget
Wood River
Hammond Sanitary District
Indianapolis
Kokomo
Kansas City
Louisville/Jefferson County MSD
(Louisville)
Saint Martinville
Fall River
Holyoke - .,
Massachusetts Water Resources Authority
(Boston)
Springfield
Templeton WWTF (Baldwinville)
Upper Blackstone (Millbury)
Upper Potomac River (Westernport)
Hartland
Detroit .
Kalamazoo
Muskegon County
Metropolitan Waste Control Commission
(Minneapolis/St. Paul)
Western Lake Superior (Duluth)
SL Joseph
• St. Louis MSD
Springfield
Gastbnia
Joint Meeting of Essex and Union (Elizabeth)
2.0
2.6
4.4
32.6
1.2
1,5
2.0
8.3
6.2
1.7
2.5
3.3
1.4
13.7
39.5
1.8
2.3
4.8
2.9
2.5
1.2
3.4
1.0
3.0
1.3
5.7
1.1
2.0
2.7
1.6
6.3
3.8
3.7
2.6
2-3
3.9
64:8
1.0
1.2
1.1
7-5
-------
Table 7-2. Pretreatment Status of POTWs Receiving the Largest
Amounts of Toxic Chemicals, 1988 (continued)
State
NJ
NY
OH
OR
PA
PR
RI
TN
TX
VA
WI
WV
Pretreatment
Status
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
—
L
L
L
L
L
L
L
L
L
L
L
L
L
Number Estimated Million
of Plants POTW* Po'unds Per Year**
1
1
7
1
1
1
1
1
3
1
4
1
1
4
1
4
1
1
1
1
3
2
1
1
2
1
1
•4
1
1
1
2
1
Linden-Roselle S.A. (Linden)
Bergen County Utility Authority (Little Ferry)
Passaic Valley Sewerage Commission (Newark)
Rahway Valley Sewage Authority
Middlesex County Utility Authority (SayreviUe)
Binghamton-Johnson CityJoint S.D. (Binghamton)
Buffalo Sewer Authority .
Glens Falls
Monroe County (Rochester)
Niagara Falls
Onondaga County (Syracuse)
Orangetown Sewer District No. 2
Rensselaer County (Troy)
Hamilton County MSD (Cincinnati)
Middletown
Northeast Ohio Regional S.D. (Cleveland)
Toledo
Youngstown
St. Helens
Erie
Philadelphia
P.R. Aqueducts and Sewer Authority -
PRASA (Barceloneta/Ponce)
Blackstone Valley District (East Providence)
Chattanooga
Memphis
Cactus :
Fort Worth
Gulf Coast Waste Disposal (Pasadena)
Hopewell
Lynchburg
Green Bay MSD
Milwaukee MSD
South Charleston
7.1 -
2.5
33.2
6.9
7.6
3.0
1.5
3.0
1.2
1.6
4.6
2.5
3.9
11.8
2.0
1.2 ,
1.1
1.9
6.4
3.8
7.9
6.7
1.5
1.1
21.5
1.8
1.4
35.4
35.3
1.0
2.3
16.8
2.8
: Approved local pretreatment program.
-; Local pretreatment program required by EPA or State approval authority, but not yet approved.
S s= State-run program regulates industrial users at POTW.
— - Not covered by local or State-run pretreatment program.
3 Location of POTW is in parenthesis if different from municipal entity name.
as Rounded to nearest 100,000 pounds.
Source: Toxic Release Inventory. POTWs listed are those to which industrial facilities reported discharging
, over 1,000,000 pounds of toxic chemicals in 1988.
L
R
*
**
7-6
-------
7.1.1.3 Relationship Between Environmental Quality and Program Coverage
The pretreatment program's goal of preventing interference and pass through
establishes a link with the CWA's broader environmental goals. Pursuant to Section .
304(1) of the CWA, EPA or States were required to identify those waters (or stream
segments) that are not expected to attain water quality standards or the designated
beneficial use after technology-based requirements are met, due entirely or substantially
to discharges from point sources of toxic pollutants. For each such stream segment, EPA
or States were to list the point sources discharging the toxic pollutant(s) believed to be
preventing or impairing water quality.2 EPA has identified 254 POTW treatment plants
that discharge to surface waters that are impaired because of point source discharges of
toxic pollutants. Of these 254 plants, 170 have approved pretreatment programs in place.
EPA or approved States are required to develop individual control strategies (National
Pollutant Discharge Elimination System [NPDES] permits) for such point sources that
will provide for compliance with applicable water quality standards within 3 years of
'establishment of the individual control strategy.
EPA Regions and States are continuing to identify POTWs with a need for
pretreatment programs. Currently, about 100 local programs are being developed. It is
likely, however, that additional POTWs, such as the 84 POTWs that are not covered by
pretreatment programs and that have been identified by EPA as causing nonattainment of
water quality standards, should be required to implement local pretreatment programs. To
the extent that industrial discharges at treatment plants contribute to pass through or
interference, EPA Regions and States will target such plants for pretreatment programs.
7.1.2 Industries and Pollutants Regulated by the National Pretreatment Program
Another measure of National Pretreatment Program effectiveness is the ability of the
program to identify those industries known to discharge toxic pollutants to POTWs and to
regulate those discharges and pollutants. Although the National Pretreatment Program is
designed to regulate all nondomestic users nationwide, in practice the efforts of most
POTWs, as well as EPA Regions and States, focus on categorical industrial users (CIUs)
and other significant industrial users (SIUs). (Chapters 3 and 5 describe in detail these
2. Development of these lists of stream segments and POTWs varies on a State-to-
State basis according to the manner in which States develop water quality standards,
assign designated uses, and identify impaired uses.
7-7
-------
two classes of industrial users.) It is estimated that approximately 30,000 categorical and
other significant industrial users are controlled by pretreatment POTWs and States.
Chapter 3 of this report discussed the industries and industrial categories that are, or
have the potential to be,, sources of toxic discharges to POTWs. For the 47 industrial
categories (and subcategories) examined previously, Table 7-3 provides the number of
categories known to discharge each of the 126 priority pollutants. It should be noted,
however, that not all facilities in a category discharge the same pollutants and that some
facilities and categories discharge very small amounts of some pollutants. Table 7-3 does
not indicate the relative magnitude of discharges; rather, it indicates only the known
presence of priority pollutants in industrial discharges. As can be seen from the
comparison of the first two. columns of this table, toxic pollutants, both metals and
organics, are discharged to POTWs by many more industries than are currently regulated
by national categorical standards. ;
EPA has devoted resources to developing standards for those industrial categories
known to discharge large amounts of toxic pollutants on a national basis (e.g.,
electroplating, metal finishing, organic chemicals). Relatively fewer resources have been
devoted to industries and categories that may be important on a local level but are of less
concern nationally. (It should be noted that Congress acknowledged that limitations in
resources would require EPA to exercise discretion in determining which pollutants should
'"' • ,»•!'' , , , "!' . I1"!1,1' '" / ',' !„ "', '!,;' U,1, * '!, ,""'' ,:," ,i, '! '" si'l,, 'I,1'!!!!',!,,,'!.! ....... ....... '.illO'V'.ji Ibim ^ ,!!M'i,,,',,'%i, , 'ii"':;,,1;1,;! ''I'"! SilB!1 „'. ' i,l ..... W! ,T,\' ........... '1 in I I ||li 11 1| ill I
be covered by national standards [House Conference Report, 95th Congress, first session,
i 95-830, p. 85].)' ' ' ; " ' '" ' ..... ' '" ' ' "''' ' ' ' " '' '":" ' '" ..... " ..... '" ..... ; : : ' " "' ^ " '' '' ' '"' " "' * ' ' ..... " '": '" " . "
The pretreatment program provides that POTWs (or states In some cases) not only
apply national standards promulgated by EPA, but also develop and implement local limits,
as necessary, to provide additional control where national stan'&irds are inadequate to
f'jf t ,,i,i' ..',. di,1.1. . . • i I,, . ,;, ..;• i ;'"• t.'- , ..... ..... 'i,,'!,;;1! if!' ..... liiitp.. :; VHgn .......... » -.'!.'. a- :.T 'JM. ..... " .......... i ........ .•%«. ......... nr<;.'. ....... .", ............
prevent pass through or interference at their facilities or to regulate other industries and
pollutants of local concern. Local limits are driven by applicable sludge standards and by
permit limits (NPDES permits and, in some cases, sludge disposal permits), as well as by
specific prohibitions outlined in the General Pretreatment Regulations (e.g., the protection
of worker health and safety). The POTW's NPDES permit limits for toxic pollutants are,
in turn, driven by EPA's secondary treatment requirements and by the application of
pertinent environmental standards (primarily State or Federal surface water or sludge
standards), which are translated into specific requirements for the PCfiTW. Table 7-3
shows the number of States that have established water quality standards (for one or
it' „ ' • ':: " '• !'," ' :" I ' " ''' . '',","" " ; , '• ' ': " I I III III
7-8
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7-14
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more types of surface waters or effects) for each priority pollutant. It also identifies those
pollutants that are proposed for regulation under the draft technical standards for sludge
. use and disposal (see proposed 40 CFR Part 503). As can be seen, less than half of the
States have standards for most toxic organic pollutants, even pollutants (such as benzene
and toluene) that are discharged by many industrial facilities and categories. Most States
do have water quality standards for pesticides (which are contributed more by
nonindustrial sources, including nonpoint sources, than by industrial sources),
polychlbrinated biphenyls, and metals.
In addition, Table 7-3 shows that relatively few NPDES permits issued to
pretreatment POTWs contain chemical-specific limits for toxic pollutants. Most permits
contain narrative restrictions., such as no toxics in toxic amounts, and some permits
contain whole effluent toxicity limits. The absence of numeric limits is particularly
noticeable for toxic organics. According to EPA's Permit Compliance System (PCS), less
than 2 percent of pretreatment POTWs are subject to limits for any single toxic organic
pollutant. Limits on metals are somewhat more common, although less than 16 percent of
pretreatment POTWs are subject to limits on copper, which is the priority pollutant most
commonly limited in NPDES permits. Since the regulatory definitions of pass through and
interference (the environmental basis for the program) are tied to the POTW's NPDES
permit limits, the general lack of toxic limits in permits restricts the POTW's basis for
developing local limits.
To address local interference and pass through problems, the POTW must establish
local limits. Table 7-3 shows the percentage of POTWs (out of a sample of 200 POTWs
known to have local limits) with numerical local limits for specific priority pollutants.
Although relatively few POTWs have local limits for toxic organics, most POTWs place
limits on metals and cyanide (about 80 percent of POTWs have local limits for six metals).
In large part, this is due to EPA's local limits policy issued in 1985 and extensive guidance
issued in 1987, which promoted local limits, particularly for metals, cyanide, and other
pollutants of particular concern, based on their widespread occurrence in POTW influent
and effluent and their potential for causing adverse effects on POTW operations. As noted
in Table 7-3, many POTWs have developed local limits covering more toxic pollutants than
they themselves are regulated for in their NPDES permit (e.g., cadmium, lead, and
chromium).
7-15
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Commercial and domestic sources may also be major contributors of toxic pollutants.
As industrial users reduce their pollutant loadings, toxic pollutants from commercial and
domestic sources may become more significant. Beyond any improvements that may be '
made in the coverage of major industries and pollutants currently being addressed, the
regulation by POTWs of other nondomestic users currently not considered significant
sources of toxic pollutants may reduce pollutants further. The flexibility of the National
Pretreatment Program allows POTWs to address local environmental concerns
themselves. Each POTW has the ability to tailor its pretreatment program to reflect site-
specific circumstances, but local POTWs are sometimes constrained by ,a lack of permit
limits on which to base the development of local limits.
7.2 PROGRAM IMPLEMENTATION
•" J, • ; ' , » "•;';•." ;" ; • ". ; I ' III I M1 ' I I I. I "
This section evaluates the implementation status of the National Pretreatment
Program at the local level, at the State level in cases where the State implements the
program, and at the EPA level. Implementation activities include identifying industries
discharging toxic pollutants, issuing control mechanisms, inspecting ami sampling the
industries, and taking enforcement actions where necessary to obtain compliance. Such
activities are necessary to achieve reductions in the discharge of toxic pollutants to
POTWs.
111 ,„''"' , mi i i ii
7.2.1 POTW Pretreatment Programs
EPA and the States monitor implementation of local POTW pretreatment programs
using three tools: annual pretreatment compliance inspections (PCIs), program audits,
and annual reports. A PCI evaluates the POTW's compliance monitoring and enforcement
program. It usually lasts for 1 day and may include inspections or visits to local industrial
users. An audit, in contrast, is more detailed than the PCl'"and. is conducted less
v •; j1'' i • i ••,,. if: ,' •. • ;.' • : "h,, [ ;•. • i'"; • t,,,;,,"'. .-• k' 1:1 ;•.; ij ill i; lilts 'sse-K*. *, if«"i a::"iu •;;,;< ,* wjr 'a i n n" • a:,; •• VSMH •» i '<.,: ;.L':: vii' « 111
frequently, usually once every 5 years. An audit, which examines all aspects of the
POTW's pretreatment program, may take 1 to 3 days and includes interviews with local
officials, file reviews, and industrial site visits. POTWs are also required to submit, at a
minimum, annual reports on program performance that summarize the POTWs' program
activities. Some EPA Regions and the States require these reports to be submitted more
frequently.
Information collected from these activities is entered into EPA's Permit Compliance
System (PCS). As described in Chapter 2, the PCS data base has 65 discrete data
elements pertaining to pretreatment implementation. Most of the data fields containing
7-16
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these elements are blank since data entry is required for only 15 of these elements (largely
because of resource constraints). ,
Table 7-4 summarizes the PCS information on 12 programmatic measurements. The
data indicate that most SIUs have been issued control mechanisms and have been
inspected or sampled. Significant non-compliance (SNC) by SIUs is high compared to the
level of SNC for direct dischargers; an estimated 17 percent of the SIUs are in SNC with a
discharge limit, a monitoring or reporting requirement, or a compliance schedule as
compared to 7 percent for direct dischargers.3 A document on industrial compliance in the
Great Lakes region (LfC, 1989) reported 17 percent of the industries in SNC in four States:
Michigan, Ohio, Indiana, and Wisconsin. A General Accounting Office survey (GAO,
1989) of 428 POTWs reported that 41 percent of the industrial users were in violation of
one or more of their discharge limits.
When confronted by noncompliance, POTWs rely overwhelmingly on issuing notices
of violation and administrative orders. PCS indicates that 84 percent of all pretreatment
POTWs have taken such actions. Civil or criminal enforcement actions against
noncompliant industries appear to be taken much less frequently. Only 5 percent of
POTWs have pursued these enforcement actions. However, this does not necessarily
indicate ineffective enforcement; if a POTW issues a large number of notices of violation
that effectively obtain compliance, the POTW does not need to initiate civil actions.
.Another indicator of effective enforcement may be a low percentage of repeat violators, but
this type of information generally is not gathered during audits or PCIs or provided in
POTW annual reports.
While the PCS data, which provide a measure of programmatic implementation, indicate a
. , • • ' s '
high rate of programmatic implementation activity, significant implementation problems
persist. Based on audit information, EPA has identified a number of program
implementation deficiencies that may comprise the effectiveness of these activities in
3. Based on information from 97.2 percent of the POTWs with approved local programs.
7-17
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Table 7-4. Status of POTW Program Implementation
Program Activities
Evaluation
Local Limits1'2
86 percent of POTWs have completed required technical
evaluation.
82 percent have adopted technically based local limits.
Permitting
• 84 percent of SIUs have been issued control mechanisms.1'3
Compliance Monitoring
90 percent of SIUs have been inspected or sampled.1'3
Enforcement
Total number of SIUs in SNC ranges from 10-17 percent.1
- SNC with standards and reporting requirements is 10
percent.
- SNC with self-monitoring requirements is 4 percent.
- SNC with schedule requirements is 3 percent.
• 44 percent of POTWs with SIUs in SNC have not published a
list of these violators in the local newspaper.
' 5 percent of POTWs have taken civil or criminal enforcement
actions against noncompliant lUs.
• 84 percent of POTWs have issued notices of violation or
administrative orders.
• 15 percent of POTWs have collected penalties from
noncompliant lUs.
• 20 percent of POTWs with SIUs in SNC have taken no
enforcement actions.
1. Based on information from 97.2 percent of POTWs with approved programs.
2. According to Table 5-10, another data source (PASS) suggests that while the percentage of POTWs with
local limits in place is very high (90 percent), the percentage with technically based local limits is about
34 percent
3. Based on a universe of 30,280 SIUs.
Source: PCS (1990).
7-18
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reducing toxic discharges. Table 7-5 lists these deficiencies, the most common of which
are as follows:
• Correct discharge limits were not applied (i.e., not all the pollutant limits were in
the control mechanisms, the wrong categorical standards were in the control
mechanisms, or the local limits were not in the control mechanisms). POTWs
continue to have difficulty determining whether a particular industrial facility is
subject to categorical standards and whether the most stringent limit for a
particular pollutant is the categorical standard or the .local limit. In addition, they
often apply production-based standards incorrectly because of errors in identifying
all regulated processes and production levels.
• The sampling location either was not identified in. the control mechanism or was
incorrect.
• Inspections were not adequately documented, and sampling chain-of-custody
procedures were not employed or not completed.
• Samples were not analyzed for all regulated pollutants; inspections were not
sufficiently comprehensive to identify all wastestreams containing possible toxic
pollutants and to evaluate the adequacy of industrial controls and industrial self-
monitoring.
• Sample collection and analytical protocols are improper.
• Enforcement actions are inadequate. POTWs have been reluctant to take stronger
enforcement actions because (1) POTWs have traditionally been service-oriented
toward industries and in some cases are uncomfortable in the role of regulators,
and (2) some have received unenthusiastic enforcement support by local
government officials (e.g., city councils, mayors, or district boards) because of
possible economic impacts (GAO, 1989). • ' ' ' .
The Agency has developed guidance for reporting and evaluating POTW
>, ' ' . ' ' ' i
noncompliance with pretreatment requirements. This guidance establishes criteria
covering five basic areas of POTW program implementation: (1) control mechanisms,
(2) inspection and sampling, (3) POTW enforcement, (4) POTW reporting to the approval
7-19
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Table 7-5. Specific Program Deficiencies Identified in Audits
Program Element
Type of Deficiency1
Control Mechanism
Sampling location not identified
Applicable discharge limits not specified
Standard conditions missing
Sample type not specified
Self-monitoring requirements not present
Reporting requirements not present
Effective and/or expiration dates not specified
Reference to legal authority/ordinance lacking
Other (including no control mechanisms)
Application of Categorical Standards
Appropriate TTO limitation not applied
Inaccurate, incomplete, or no category/subcategory determinations
Sampling location does not contain all regulated flows or is not
representative
Combined wastestream formula not used or used improperly
More stringent limitation (local limits vs. categorical standards) not
applied
All categorical industrial users not identified
Appropriate long-term average not applied
Production-based standards not applied or misapplied
Inspections
Inspections not documented adequately
• All categorical and other significant industrial users not inspected
Categorical and other significant industrial users not inspected annually
Inspections not comprehensive
Sampling
Inadequate chain-of-custody procedures
. All categorical and other significant industrial users not sampled
Improper or inadequate parameters sampled
Inadequate sampling frequency
Inadequate sample types
Improper sampling protocols
1. Deficiencies are riink ordered by prevalence.
Source: PASS (1990).
7-20
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authority, and (5) other requirements. These criteria provide the framework to determine
whether the POTW is considered in "reportable non-compliance" (RNC).4
With regard to these criteria, recent data from PCS show that:
. • Fifteen percent of all 1,442 pretreatment POTWs have failed to issue control
mechanisms to 90 percent of their SIUs.
• Twelve percent of pretreatment POTWs have failed to inspect or sample at least
80 percent of their SIUs.
• Twenty-nine percent of pretreatment POTWs have determined that at least 15
percent of their SIUs are in SNC.
• Twenty percent of POTWs with SIUs in SNC have failed to take any enforcement
action against their non-compliant SIUs.
• Forty-four percent of POTWs with SIUs in SNC have failed to report those SIUs
in the largest local newspaper.
EPA has determined that 44 percent of the Nation's POTWs with approved
pretreatment programs meet at least one of the four major RNC criteria. Once a facility is
determined to be in RNC, it must be reported on EPA's Quarterly Non-Compliance Report
(QNCR). If a facility is on the QNCR for two or more quarters, formal enforcement action
must be initiated against the facility.
Various guidance and training activities have addressed these deficiencies. EPA and
States actively assist local officials by providing guidance and holding workshops oh
various aspects of the pretreatment program. EPA's pretreatment guidance documents
have increased from 12 in 1985 to 39 in 1990. Table 7-6 lists most, if not all, of these
4. RNC is defined as failure to take effective action against lUs for instances of pass
through and/or interference; failure to submit pretreatment reports (annual report or
publication of significant violators) to the approval authority within 30 days of a
specified due date; failure to complete a pretreatment implementation compliance
schedule milestone within 90 days of a specified due date; failure to issue, reissue, or
ratify control mechanisms for at least 90 percent of the SIUs within 180 days of a
specified date; failure to conduct a complete inspection or sampling of at least 80
percent of the SIUs; failure to enforce pretreatment standards and reporting
requirements; and any other violation of substantial concern to the approval authority.
See FY 1990 Guidance for Reporting and Evaluating POTW Noncompliance With
Pretreatment Requirements. EPA Office of Water Enforcement and Permits,
September 1989 (EPA, 1989a).
7-21
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Table 7-6. Guidance Materials Applicable to the Pretreatment Program
General Guidance Manuals for POTWs
Guidance Manual for POTW Pretreatment Program Development (October 1983)
Guidance Manual for Preparation and Review of Removal Credit Applications (July 1985)
RCRA Information on Hazardous Wastes for POTWs (September 1985)
Environmental Regulations and Technology—The National Pretreatment Program (July 1986)
Pretreatment Compliance Monitoring and Enforcement Guidance (September 1986)
Guidance Manual for the Identification of Hazardous Wastes Delivered to Publicly Owned Treatment Works
by Truck, Rail, or Dedicated Pipe (June 1987)
Guidance Manual for Preventing Interference at POTWs (September 1987)
Guidance Manual on the Development and Implementation of Local Discharge Limitations Under the
Pretreatment Program (December 1987)
Non-Consent Decree Categorical Pretreatment Standards (August 1988)
Guidance Manual for Control of Slug Discharges to POTWs (February 1989)
Memorandum: Local Limits Requirements for POTW Pretreatment Programs (August 5,1989)
Industrial User Permitting Guidance Manual (September 1989)
Guidance for Developing Control Authority Enforcement Response Plans (September 1989)
Overview of Selected EPA Regulations and Guidance Affecting POTW Management (September 1989)
Supplemental Guidance on the Development and Implementation of Local Discharge Limitations Under the
National Pretreatment Program (draft) (December 1990)
Guidance Manuals on Application of Categorical Standards
Guidance Manual for Electroplating and Metal Finishing Pretreatment Standards (February 1984)
Guidance Manual for Pulp, Paper, and Paperboard and Builder's Paper and Board Mills Pretreatment
Standards (July 1984)
Guidance Manual for the Use of Production-based Pretreatment Standards and the Combined Wastestream
Formula (September 1985)
Guidance Manual for Iron and Steel Manufacturing Pretreatment Standards (September 1985)
Guidance Manual for Implementing Total Toxic Organic (TTO) Pretreatment Standards (September 1985)
Guidance Manual for Leather Tanning and Finishing Pretreatment Standards (September 1986)
Guidance Manual for Battery Manufacturing Pretreatment Standards (August 1987)
Categorical Pretreatment Standards Summary (March 1988)
Guidance Manual for Aluminum, Copper, and Nonferrous Metals Forming and Metal Powders Pretreatment
Standards (December 1989)
Guidance Manuals for Approval Authorities
Procedures Manual for Reviewing a POTW Pretreatment Program Submission (October 1983)
Guidance Manual for Preparation and Review of Removal Credit Applications (July 1985)
Pretreatment Compliance Inspection and Audit Manual for Approval Authorities (July 1986)
Guidance for Implementing RCRA Permit-by-Rule Requirements at POTWs (July 1987)
Guidance for Reporting and Evaluating POTW Noncompliance With Pretreatment Implementation
Requirements (September 1987 and September 1989)
NPDES Compliance Inspection Manual (May 1988)
7-22
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guidance documents. In addition, EPA has issued eight pretreatment bulletins since 1985.
The number of workshops held annually by EPA has increased from 3 in 1983 to 46 in
1990. POTWs responding to the GAO survey ranked EPA guidance as one of the most
important factors having a positive impact on program implementation and, thus, improving
POTW and industrial compliance.
Furthermore, EPA has recently amended the General Pretreatment Regulations (40
CFR Part 403) in response to the findings of the Domestic Sewage Study (DSS). These
regulatory changes were principally aimed at strengthening the program's control of
i
hazardous waste discharged to sewer systems. However, several of these regulatory
provisions, listed below, will also address some of the pretreatment program deficiencies
identified previously.
• POTWs with local programs must issue permits or equivalent control mechanisms
to SIUs. Control mechanisms must contain, at a minimum, such elements as
discharge limits and monitoring and reporting requirements. These changes should
improve control over SIU discharges.
• The prohibition against hauled wastes except at designated sites will improve the
control of liquid waste haulers, which may be a significant source of unpermitted
toxic discharges.
• The requirement to inspect and sample all significant industrial users annually will
improve POTW control of the discharges from regulated industrial users.
• The requirement that local officials commit their enforcement procedures and
protocols to writing in an enforcement response plan is expected to promote more
timely arid consistent enforcement actions. Once approved by EPA or approved
States, the enforcement response plan becomes an enforceable part of the
POTW's local program. At this time, only two States have provided information in
PCS on the status of POTW enforcement response plans for a majority of their
POTWs. Kentucky indicates that 10 percent of its POTWs have such plans, and
Illinois reports that 42 percent of its POTWs have them.5
7.2.2 States as Control Authorities
Under 40 CFR 403.10(e), States may assume responsibility for carrying out the
requirements of the National Pretreatment Program in lieu of requiring POTWs to develop
local programs. Five States—Alabama, Connecticut, Mississippi, Nebraska, and
5. States are not required to enter information on enforcement response plans in PCS.
This information is not available for about 91 percent of the POTWs.
7-23
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Vermont—administer the National Pretreatment Program at the State, rather than the
local, level. EPA recently audited these State-run programs. The Agency believes that
the effectiveness of these programs is generally comparable to locally administered
programs. The States used NPDES permitting-type procedures to regulate both
categorical and noncategorical industries, inspected and sampled industrial users, and
imposed penalties for violations with nearly the same frequency''as locally administered
programs.
The audited State programs were generally less effective than POTWs in some
respects. States had not developed technically based local limits to cover discharges to
individual POTWs, although local factors were taken into account in developing some
individual permits. The States were less likely than POTWs to use formal enforcement
procedures, such as administrative orders or notices of violation. States failed to publish
the names of significant violators in local newspapers. Compared to locally run programs,
State-run programs also regulated a lower proportion of noncategorical SIUs compared to
total SIUs.
Some States run the program at both levels. For example, Ohio has required 100
POTWs to run local pretreatment programs. Yet, at smaller POTWs without pretreatment
programs, the State regulates categorical industrial users directly. States that regulate
some SIUs directly tend to have the same program deficiencies as the 403.10(e) States
with regard to developing and applying technically based local limits. The top part of Table
7-7 provides some limited data on the permitting aM'mspectFcm' activities of States for
nonpretreatment POTWs and the industrial user compliance status of those industries
directly regulated by the States. Most states listed here have issued some type of control
mechanism] but several States have dtfficulty in "inspecting a! slUs. this table reflects
data contained in PCS and does not reflect the results of the recent audits by EPA.
11 ', ,•• ,'•'•,' i „ /
'!•; ! . :.. ' •."':' '"'• " '".,i ill, Tr, , « i
7.2.3 EPA as the Control Authority
11 " ' *•'..''-., I n i ii i i i
Where a POTW has not been approved to administer a local pretreatment program
and the State has not been approved to administer the National Pretreatment Program,
EPA remains the control authority. As was indicated in Chapter 3 (Table 3-1), locally run
programs regulate far more industrial facilities than EPA. This is particularly true for
noncategorical industries; for example, in four of the six EPA Regions for which data were
available, no noncategorical SIUs were regulated by EPA. The difference in coverage of
7-24
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Table 7-7. State and EPA Activities as Control Authorities for Non-
Pretreatment POTWs
States as Control Authority: Control of SIUs Discharging to Non-Pretreatment POTWs
in States With Approved State Pretreatment Programs
State
CT1
RI
VT1
NJ.
ALi
MS1
AR
IA
MO
UT
SIUs
(No.)
250
14
14
8
310
117
27
46
24
4
SIUs in SNC
(No.)
60
0
8
3
0
11
1
7
2
0
(%)
24
0
57.1
37.5
0
9.4
3.7 ,
15.2
8.3^
0
SIUs Inspected
(No.)
228
14
9
0
299
117
1
23
24
0
(%>
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100
64.3
0
96.5
100
3.8
50
100
0
SIUs With Control
Mechanism
(No.)
152
, 0
14
6
310
117
0
46
24
4
(%)
60.8
0
100
75
100
100
0
100
100
100
EPA as Control Authority: Control of SIUs Discharging to Non-Pretreatment POTWs
in States Without Approved State Pretreatment Programs
State
MA
ME
NH
NY
PA
FL
KS
CO
MT
ND
SD
WY
SIUs
(No.)
42
16
30
23
16
8
36
21
1
10
25
1
SIUs in SNC
(No.)
0
0
1
7
7
0
10
0
0
0
0
0
(%)
0
0
3.3
30.4
43.7
0
27.7
0
0
0
0
0
SIUs Inspected
(No.)
42
0
1
0
11
5
36
0
0
0
0
0
(%)
100
0
3.4
0
68.8
62.5
100
0
0
0
0
0
SIUs With Control
Mechanism
(No.)
0
0
0
0
12
8
36
21
1
10
25
1
(%)
0
0
0
0
75
100
100
100
100
100
100
100
1. State-run pretreatment program.
Source: PCS (1990).
7-25
-------
noncategorical SIUs is largely due to EPA regional priority on ensuring effective local
program implementation.
Again, there are limited data on EPA activities where it is the control authority, but
as the information in the bottom part of Table 7-V indicates, EPA, and unapproved States
under agreement with EPA, have not issued control mechanisms to all SIUs nor have they
conducted inspections at all SIUs. Also, pretreatment programs at the regional level lack.
established procedures, such as those under the NPDES system for direct dischargers, for
developing and applying effluent limits. (Categorical industries, by contrast, are required
by law to identify themselves to regulatory authorities, and their effluent limits are
provided in national guidelines.)
Twenty-two States are included in Table 7-7; since all SIUs in Michigan and North
Carolina are regulated under local programs, 24 States are represented. Because PCS
data are unavailable for the remaining States and coverage may also be incomplete for the
States in the table, EPA estimates that the table covers less than half of the SIUs
nationwide where EPA or the State is the control authority.
7.2.4 EPA and State Oversight Activities
EPA and approved States have an important oversight role in the National
Pretreatment Program. Currently, 27 States have approved pretreatment programs. EPA
exercises direct oversight in the remaining 30 States and Territories. Under the CWA,
every State that has been authorized to implement the 'NFDE§ program was required to
obtain, by 1980, authority to administer the National Pretreatment Program as well. Of the
39 NPDES States, 27 have approved pretreatment >:jpmffaS^i""'ih.c"ii with NPDES
authority but not pretreatment are:
• ,„ ' ••• - ••••;: ••:'• '' •'..-.'"•'•['"" .
• Colorado
• Delaware
• Illinois i ' , .
• Indiana
.1 • . >;• , . '• ' - . '. ' ' ;" • '•••-, ;•',''••'•;&'.'. ''*Jii;i*.':'!'.'" >::•• •'"'.''.",.••',!!• •!>'••"''!''' .• ' ' •|l
• Kansas
• Montana
• Nevada . ' '.
• New York
7-26
-------
• North Dakota •
• Pennsylvania
• U.S. Virgin Islands
• Wyoming.
The most frequent reason for these States not having assumed pretreatment program
responsibilities is inadequate legal authority and resources to administer all aspects of the
program. Most of these States do, however, perform some of the required activities. For
example, some States, such as Indiana and Kansas, conduct oversight activities through a
memorandum of agreement with EPA.
Between 1985 and 1990, EPA and the States performed 3,601 PCIs and audits at
. 1,328 (92%) of the 1,442 approved POTW pretreatment programs.6 From July 1, 1989, to
June 30, 1990, 70 percent of the POTWs with approved programs were audited or
inspected (PCS, 1990).
The Agency's oversight role includes an enforcement component. EPA has
conducted two pretreatment enforcement initiatives targeting POTWs. In 1985, it filed
civil complaints against 20 POTWs for failure to submit an approvable local pretreatment
program. In October 1989, EPA initiated a special pretreatment enforcement initiative in
which 61 POTWs were targeted for administrative penalty orders or judicial enforcement
for failure to implement their programs. Subsequently, EPA and the States have taken
similar action against an additional 37 cities; the Agency is making plans to take
enforcement actions against additional cities.
• • • ' -'.''• • ' '
In the past 2 years, the number of pretreatment administrative orders issued by EPA
and the States against noncompliant POTWs and industrial users has grown from 261 in
fiscal year 1988 to 323 in fiscal year 1989 (EPA, 1990a). During that same time, the
number of judicial referrals by States and EPA dropped from 617 in FY 1988 to 405 in FY
1989. The number of administrative penalty orders issued by EPA against POTWs and
6. Information from two data bases (Pretreatment Audit Summary System [PASS] and
PCS) was used to determine the number of audits conducted and number of POTWs
audited. It is likely that additional audits and inspections were performed by States
and EPA Regions in 1984, 1985, and 1986 than are recorded in either PASS or PCS.
7-27
-------
industrial users for pretreatment violations has increased from X in 1987 to 42 as of August
1,1990. The number of civil judicial penalty cases for pretreatment violations filed by EPA
since 1987 is 61; approximately half of those cases were against POTWs. Although less
frequently used than administrative or civil actions, criminal prosecutions have been taken
against industries and POTWs for pretreatment violations 15 times since 1983; 8 of these
cases were filed in 1989.
The civil enforcement actions, on average, take approximately 13.5 months to resolve
when brought against industrial users and 15.5 months when brought against POTWs.
Although some have been resolved in less than a month, the longest case against an
industrial user took 43 months and tne longest case against a POtW took 51 months.
According to EPA internal tracking, the average penalty assessed against POTWs for
pretreatment violations since 1984 was $55,000; the average penalty assessed against
industries in the same period was slightly higher ($61,000). The Agency has received
approximately $2.2 million in penalties from POTWs and about $63 million from industries.
The total penalty amounts may be underestimated, however, since many pretreatment
enforcement actions are often part of larger NPDES enforcement actions.
7.3 PROGRAM PERFORMANCE
This section examines the effectiveness of the National Pretreatment Programin
achieving environmental objectives. As previously describe
-------
• EPA's national data base for PQTW effluent quality is archived after6 years.
Information in the system is incomplete for many States, particularly in FYs 1984^
1986; records before 1984 have been deleted.
• As pointed out in previous chapters, ambient environmental data (particularly for
toxic organic?) that measure the program's environmental effectiveness are not
collected with any consistency.
The above limitations notwithstanding, it is still possible to develop some insights
into POTWs' achievement of the objectives of the National ^Pretreatment Program. EPA
took two approaches to arrive at these insights. First, the Agency reviewed
environmental data available at. POTWs as a result of audits and PCIs, submissions of
annual reports and local limits, and the nomination and evaluation process for EPA's
pretreatment excellence awards, Unfortunately, none of these activities is designed
.specifically to obtain environmental data that would support rigorous examination of the
program's environmental effectiveness. (PCIs and audits, for example, focus on
programmatic activities and ask only two questions regarding environmental
effectiveness.)
As an alternative approach, EPA used studies or reports, performed by individual
POTWs on an ad hoc basis, that document environmental effectiveness. Because
environmental results from such sources are not statistically representative of the 1,442
pretreatment POTWs nationwide, EPA did not extrapolate them to the large population of
POTWs or pollutants. Thus, EPA presents them here as illustrative— rather than
representative— of pretreatment program effectiveness.
7.3.1 Water Quality
7.3.1.1 Pollutant Concentrations in POTW Influent and Effluent
Measurement of pollutant loadings is perhaps the most direct way to assess the
effectiveness of the pretreatment program in reducing pollutant discharges to and from
POTWs. However, pollutant loadings are also affected by factors other than pretreatment.
Such factors can mask the influence of pretreatment on pollutant loadings to surface
waters. Such factors include the following: .
e nr decrease in flbw— Changes in wastewater flow, with no change in
pollutant concentration, can result in increased or decreased loadings of pollutants.
7-29
-------
11 I' :
• Growth or decline in industrial base—Pollutant loadings can change due to an
increase or decrease in the number of industrial dischargers and in the production
levels of dischargers.
• Modifications at POTW—Upgrading the treatment processes at the POTW can
improve effluent quality even if influent loadings remain the same.
To illustrate some of these factors, the following paragraphs present a few examples
documented by POTWs.
- • *' • - '.' " • i; .• , i, •;, .' ,'•'•• '•.': •". '•'v'.;" • J • • isiii:1 '"'ii;": •>••;'';':'' < •,.«•,"•::''•'•• \ '•";?'•• -•• •'',;" •'•'";;.', 1 w,ii;ai-.';< f •• v;• an
Union Sanitary District. California
Despite an increase in plant flow of 6 mgd and an increase in number of SIUs from 11
to 47, the Union Sanitary District of California reports that the total quantity of metals
discharged to San Francisco Bay was reduced from 68.5 kilograms per day to 20.8 kg/day
from 1975 to 1985, as a result of its pretreatment program.
Narragansett Bay Commission. Rhode Island
The Narragansett Bay Commission operates a 64 mgd secondary treatment plant
with daily average flow of 54 mgd, 10 percent of which is industrial wastewater. There are
169 SIUs, of which 123 are categorical industries. The; bommissibn"monitors" its influent,
,, t , ,i, ':'!iv II. , ' , 'i,! .,,"'.''." H I Illlll I I III I I I I I I I I
effluent, and sludge for metals and cyanide about six to eight times per month. From these
data, it has calculated total metal loadings to the POTW. As Figure 7-1 indicates, the
total metals loading decreased from 954,099 pounds per year in 1981 to 144,513 pounds
per year in 1989., The Commission attributes this decrease in metal loadings to
installation of pretreatment equipment by its metal finishers. However, cieclihes in metal
loadings were evident before me 1983 deadline for ' compliance'"wra standards
for metal finishers and before the Commission began implementation of its approved
pretreatment program in 1984. The Commission revised its local limits in 1987 and saw a
large decline in the total metals occur the next year (from 313,257 pounds in 1987 to to
144,513 pounds in 1989). :
Cedar Rapids. Iowa
The Cedar Rapids POTW has a daily average flow of 34 mgd; 32 percent of the flow
' •. '' '"'jl!' (••'•, ' •, • :| • ' , ,.'••' f ••;!"•'. I.' r '.••:•'.:• .f i ''i,N :fi f 11*! '" v 111 i , B»W ;;. t"!ii'!!" 1!" Is' if" E ¥ i" •: 11 T1"* vl •' ,i«, ' ."f'lr •> •! ,£ i MB!:' f .••
is industrial. Twelve CIUs and 10 other SIUs are in the POTW's service area. The
• - • • . ' ; ,• , • " ' : / :'.•<••:;:'{,.';•,!;->, \\,•.:•',>'"i>;i:;im,•.ms-AimmMJ-'Ji:!':i;!is'i ;*41?m-,s.m - K• •*,i>.*:.«.«« ,i:;i>»w m
POTW found that, with one exception, categorical standards for metal finishing protected
< • "'." , < • i",, «,,, •<" , ', i ,;, 'i,, „": i <; 'i h, i'; ill, i HI r» ',: „; j'...",', i ,<;:,' P« : f „, . , >, ; i, „ H fJ ''lin,»>, v 'iMnlli1' • ' t'f
the plant and receiving stream. However, it determined that a more stringent limit was
required for cadmium. Prior to pretreatment, the cadmium concentration in sludge was
between 25 and 30 milligrams per kilogram (mg/kg) and was sufficiently high to restrict
"• • , ' .' • • '''•': i '' ''',:• M '
7-30
-------
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'7-31
-------
,iTV'!,!!^^
I'1"1']*!!!".111" ' jl
..-. '"'M' r • ',.•'.,•'": •' .it1 :<'•':,'!'"'.-. •'• • -':•'i a."'' i''I!!1*:? M 'if' •,•;•:' it'' \ '-i'lif W1. •.•. Mi; y>.':' § '• if • • ''-3 MffiiB'1. * K '-.:
land application of the sludge. After implementation of the pretreatment program and the
stricter local limit, the cadmium concentration was reduced to10 to 15 nig/kg, which is
below the State sludge criterion for land application. Copper and nickel reductions were
also observed after the pretreatment program began.
Miami-Dade Water and Sewer Authority. Florida
The Miami Dade Water and Sewer Authority (WASA)in Florida found that the
application of categorical standards alone was not sufficient to safeguard its sludge
disposal practice adequately. The Miami-Dade WASA' ; „;, •,,,, i ,1*,, j; •',, f, K i»'"
operating hours and during weekends; detailed inspections of CIUs were also conducted,
and automatic samplers were installed in the collection system to identify illegal dumps.
These efforts determined that 13 of the 26 metal finishers were in violation of the iriore
stringent local limit for nickel. When the majority.of these violators achieved compliance,
• the nickel levels were reduced significantly so that by February 1989 the sludge quality
was within Grade" I criterion.
Erie. Pennsylvania
The City of Erie, Pennsylvania,.operates a 68.6 mgd secondary treatment plant with
daily average flow of 53.8 mgd; 32 percent of this flow is industrial "wastewater It services
41 SIUs; 21 of them are categorical industries. Changes in industrial users, extensions to
the collection system, and improvements in the treatment system make it difficult to use
plant data alone to determine the impact of pretreatment on effjuent quality. However, the
reduction of regulated pollutants discharged by industrial users mat were in operation
before and after implementation of the city's pretreatment program reflects the
effectiveness of pretreatment in reducing pollutant loadings to the POTW. As illustrated
,7-32
-------
in Figure 7-2, one industrial user substantially decreased its metals concentrations
between 1986 and 1989 after installation of pretreatment equipment.
Springettsbury Township. Pennsylvania, and Lockport. New York
Both Springettsbury Township, Pennsylvania, and Lockport, New York, have reduced
NPDES violations. Springettsbury indicates that, while pretreatment contributed to the
reductions, major physical improvements to the treatment process and modifications to
NPDES permit limits probably contributed significantly to' the 99-percent reduction in
NPDES violations over the past 10 years (271 violations in 1978, 3 in 1988). On the other
hand, the pretreatment coordinator of Lockport indicates that pretreatment program
implementation was one of the major factors in reducing the number of NPDES violations.
Lockport, which experienced 191 violations in 1986, reduced the violations to 1 in 1988 and
had none through May 1989. Lockport indicated that an industry in violation of its
phosphorus limit was, in turn, causing the POTW to violate its NPDES permit limit. Once
the industry was identified and achieved compliance, the POTW met its NPDES permit
and the need for phosphorus removal at the POTW was eliminated.
POTWs have reported reductions in loadings or concentrations of various metals and
cyanide in the influent and effluent. Table 7-8 summarizes the percent reductions reported
by 23 POTWs. Data for this table were obtained from two sources: either from one of the
case studies prepared for EPA's Supplemental Guidance (EPA, 1991) or from applications
submitted by POTWs for pretreatment excellence awards. As Table 7-8 shows, POTWs
from less than 1 mgd to greater than 100 mgd have experienced reductions in pollutant
concentrations or pounds ranging from 16 to 100 percent. It should be noted, however, that
a rigorous statistical analysis of the data in this table was not possible because raw data
and other factors that may have affected pollutant reductions were not available.
California Regional Water Quality Control Board
The California Regional Water Quality Control Board in San Francisco reports that
the toxic heavy metal loadings for arsenic, cadmium, chromium, copper, lead, mercury,
nickel, silver, and zinc to the San Francisco Bay have, been reduced by 80 percent from
1,439 kilograms per day in 1975 to 287 kilograms per day in 1985 despite a 15 percent
increase in flows from municipal waste water treatment plants to the Bay (Wu, et al.,
1989). The Bay receives treated municipal wastewater from 29 POTWs. Historical .
7-33
-------
32.5
Before Pretreatment
Source: EPA (1990b).
Cadmium Q Zinc
I I Chromium 53 Cyanide
After Pretreatment
Figure 7-2. Metals Reductions by an Industry in Erie, PA
7-34
-------
Table 7-8. Reported Reductions in Concentrations or Loadings of Metals
and Cyanide in Influent and Effluent
POTW
(actual flow)
Holly, MI
(0.8 tngd)
East Providence, RI
(4.2 mgd)
Lewisville, TX
(6.2 mgd)
Cranston, RI
(12 mgd)
La Crosse, WI
(14 mgd)
Muncie Sanitary
District, IN
(17.5 mgd)
Springfield, OH
(19.9 mgd)
Union Sanitary District
(Fremont), CA
(22.4 mgd)
Harrisburg, PA
(24 mgd)
Source*/
Years
B/85-87
C/79-89
B/85-89
B/85-89
B/81-88
B/72-89
B/84-89
A/75-85
A/87-89
Reductions :
in Influent
(Est.)
Zn - 90%
Cd-89%
Cr - >75%
Cu-43%
Pb - >68% 1
Ni->70%
Zn - 43%
Pb - 100%
Zn-44%
Unknown
(Est.)
Cd - 90%
Cr - 71%
Cr-75%
Cu - 75%
Pb-98%
Ni - 92%
Zn - 80%
Unknown
Unknown
Cd - 60%
Cu - 33%
Cr - 84%
Zn - 16%
Reductions
in Effluent
Unknown
Cd-94%
Cr-76%
Cu - 66%
Pb-90%
Ni - >54%
Zn-44%
Unknown
(Est.)
Total metals - 52%
Cd-85%
Or -61%
Cu-38%
Pb-74%
Ni - 46%
Ag-20%
Zn-17%
Unknown
*»
Cr-92%
Cu-83%
Pb - 98%
Ni-97%.
Zn - 79%
Cd - 50%
Cr - 79%
Cu-74%
Pb - 37%
Ni - 79%
Zn - 80%
Total metals - 70%
Cu-87%
Pb-33%
Zn - 23%
7-35
-------
Table 7-8. Reported Reductions in Concentrations or Loadings of Metals
and Cyanide in Influent and Effluent (continued)
POTW
(actual flow)
Winston-Salem, NC
(30 ragd)
Cedar Rapids, IA
(34.15 mgd)
Nanagansett Bay
Comm.
(49.77 ragd)
Grand Rapids, MI
(54.5 mgd)
Dayton, OH
(67 mgd)
Fairfax County
(Lorton), VA
(84.3 mgd)
Fort Worth, TX
(105 mgd)
Louisville & Jefferson
Counties, KY
(106.99 mgd)
Source*/
Years
B/81-90
A/82-88
A/81-89
A/69-89
B/84-90
B/75:88
B/82-89
B/80-88
Reductions
in Influent
Cd - 85%
Cr - 69%
Cu - 47%
Ni - 70%
Zn - 39%
(Est.)
Ni - 72%
1989 Total Metals - 83%
Cd - 77%
Cr-85%
Cu - 93%
Pb-72%
Hg - 74%
Ni-81%
Ag - 78%
Zn - 72%
Cn - 80%
(Est.)
Metals - 93%
Cd - 74%
Cr-88%
Cu - 75%
Pb-35%
Ni - 78%
Zn-50%
(Est.)
Cu - 45%
Cd - 100%
Cr - 30%
Hg - 71%
Ag - 100%
Zn-23%
Cd - 95%
Cu - 71%
Pb - 38%
(Est.)
Cd - 94%
Cr - 86%
Pb-89%
Reductions
in Effluent
Unknown
(Est.)
Ni - 67%
1989
Unknown
(Est.)
Metals - 92%
Unknown
(Est.)
Cu - 78%
Cr - 84%
Hg - 100%
Zn - 43%
Cd - 50%
Cu - 83%
Pb - 25%
Unknown
7-36
-------
Table 7-8. Reported Reductions in Concentrations or Loadings of Metals
and Cyanide in Influent and Effluent (continued)
POTW
(actual flow)
Hampton Roads
(Virginia Beach), VA
(135.1 mgd)
Buffalo, NY
(159 mgd)
County Sanitation
Districts of Orange
County, CA
(242 mgd)
Passaic Valley
(Newark), NY
(250 mgd)
Northeast Ohio
Regional
(Cleveland), OH
(280 mgd)
County Sanitation of
LA County, CA
(534 mgd)
Source*/
Years
A/79-87
C/87-88
C/79-89
C/78 - 83
B/77-88
A/75-Eaily
1980's
Reductions
in Influent
(Est.)
Total Metals - 41%
Zn-41%
Ag-58%
Cu-16%
Cd-67%
Cd-70%
Cr-60%
Cu - 36%
Pb - 60%
Ni-60%
Zn-55%
Hg - 99%
Three Treatment Plants
Cd - 77%, 53%, 6%
Ni - 67%, 72%, 51%
Cu - 67%, 40%, 42%
Pb - 78%, 86%, 70%
As -60%
Cd - 67%
Cr-78%
Ca - 68%
Pb-75%
Ni - 73%
Znr68%
CN - 96%
Reductions
in Effluent
Total Metals - 68%
Cd-50%
Unknown
Unknown
Three Treatment Plants
Cd - 93%, 77%, 82%
Ni - 27%, 79%, 77%
Gu - 88%, 82%, 91%
Pb - 94%, 90%, 90%
Unknown
*Key to sources:
A = EPA (1989c).
B = EPA (1990b).
C = EPA (1990d).
7-37
-------
monitoring data from 1975, 1980, and 1985 were available for 15 of the 29 POTWs, and the
total loadings from these POTWs for 9 heavy metals are graphically represented in Figure
7-3. The Board attributes these significant reductions of metal loadings to the Bay to a
combined effect of the implementation of the pretreatment program and POTWs' upgrading
to the secondary treatment level.
Hampton Roaris Sanitation District .
Figure 7-4 illustrates reductions in cumulative influent'arid effluent loadings for six
metals—nickel, chromium, lead, cadmium, copper, and zinc—that occurred at one of the
case studies, Hampton Roads Sanitation District (HRSD), from 1979 to 1987. HRSD
states that these reductions are a direct result of its pretreatment program. The
reductions occurred despite the fact that overall flow to HRSD plants increased during this
period. The increased loadings in 1984 and 1985 are attributed to the additional new
service area, additional industrial users, and three new wastewater treatment plants.
Figure 7-5 shows reductions for two metals—lead and cadmium—and Figure 7-6 shows
reductions for copper and zinc. As these figures illustrate, mfiuerit loadings of copper and
zinc do not show as dramatic reductions as the other two metals. HRSD attributes this
high "background" influent concentration to the use of copper or galvanized (zinc-coated)
plumbing in local residences. In summary, over the past 10 years, HRSD has reduced its
metal discharges greatly The District states that such discharges were 360 percent
greater in 1979 than they were in 1987.
7.3.1.2. Water Quality Criterion Exceedances
Indicators of improvements in or nondegradation of existing water quality are
influenced by factors other than the National Pretreatment Program. For example,
pollution from agricultural uses or stormwater runoff from urbanized areas can degrade the.
water quality of the receiving stream or prevent improvements to water quality despite
pollutant reductions from POTWs. Because of these other factors that contribute to water
pollution, it is difficult to evaluate the extent to which the pretreatment program has
improved or prevented the degradation of the water quality of the receiving streams.
Properly designed investigations at individual POTWs can determine the influence of each
factor and assess the pretreatment program's influence on pollutant reductions or improved
water quality. To date, however, this type of investigation for a large number of
pretreatment POTWs has not been conducted!"
7-38
-------
1=
s
2
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7-39
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7-40
-------
Lead
fcB
1979 1980 1981 1982 1983 1984 1985 1986 1987
Year
Cadmium
5-1
4-
3-
2-
1-
^Hj3&|
Influent
Effluent
Influent
Effluent
1979 1980 1981 1982 1983 1984 1985 1986 1987
Year
Figure 7-5. Influent and Effluent Reductions in Lead and Cadmium at
Hampton Roads Sanitary District's Wastewater Treatment Plants
7-41
-------
Copper
120 -i
100-
80-
60-
40-
20-
Influent
Effluent
1979 1980 1981 1982 1983 1984 1985 1986 1987
Year
Zinc
400-i
300-
200-
Influent
Effluent
1979 1980 1981 1982 1983 1984 1985 1986 1987
Year
Figure 7-6. Influent and Effluent Reductions in Copper and Zinc at
Hampton Roads Sanitary District's Wastewater Treatment Plants
7-42
-------
It is possible to project, based on a POTW's effluent quality, whether the POTW's
effluent alone could cause exceedances of water quality criteria. Using the simple dilution
model approach described 'in Chapter 6, EPA compared the instream concentrations
resulting from POTWs' effluents to national water quality criteria for pretreatment and
nonpretreatment POTWs. Results are presented in Table 7-9 for selected metals and
.cyanide. The table shows that water quality criteria exceedances occurred at both
pretreatment and nonpretreatment POTWs (less than 30 percent of POTWs reporting).
Given that toxic loadings would be expected to be much higher at pretreatment POTWs,
this may be a solid indicator of program success. Exceedances in the nonpretreatment
group may indicate that a local pretreatment program has not been required at some
POTWs where it is needed to achieve compliance with water quality criteria.
Alternatively, exceedances by nonpretreatment POTWs could indicate the presence of
other sources of toxic pollutants than industrial users.
if . • i" t .•.'".
EPA's Report to Congress Water Quality Improvement Study (EPA, 1989d) studied
the effectiveness of best available technology effluent limitations for controlling pollutant
discharges from industrial sources and the resulting improvements in the quality of the
streams receiving these discharges. The study looked at 1,546 stream reaches comprising
8,434 river miles, many of which receive POTW effluent (although the number of POTWs
discharging to the reaches looked at in the study is unknown). The study compared
receiving-water monitoring data between 1970 and 1980 to similar data from 1985 to 1988.
Table 7-10, which is excerpted from the report, summarizes the receiving-water
concentration trends for seven pollutants. Cadmium and mercury show the greatest
decreases in concentration (84 and 87 percent of the river miles improved, respectively).
Zinc showed me least improvement (69 percent improvement) and the greatest extent of
deterioration (25 percent of the river miles showed concentration increases). The report
concluded that "overall trends showed roughly 76 percent of the river miles with monitoring
data available had an overall improvement (or net decrease in pollutant concentratipns); 14
percent had a net increase (deterioration) and 11 percent had no significant change." The
study did not address the benefits of other toxic control programs, such as the
pretreatment program, on water quality improvements. However, EPA believes it is likely
that the pretreatment program's control of toxic discharges contributed to this significant
measure of water quality improvement.
7-43
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7-44
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Table 7-10. Summary of Ambient Monitoring Data Analysis:
Pollutant Trends
Cadmium
Mercury
Copper
Lead
Nickel
Zinc
Cyanide
River Miles
Percent
River Miles
Percent
River Miles
Percent
River Miles
Percent
River Miles
Percent
River Miles
Percent
River Miles
Percent
Improved
3,822.6
84
2,807.4
87
4,349.9
70
4,659.7
82
3,590.4
72
5,296.2
69
1,228.2
80
No Change
193.0
4
:31.5
1
667.3
11
279.3
5
229.8
5
498.1
6
110.7
7
Deteriorated
519.5
11
• 375.6
12
1,238.2
20
766.1
13
1,172.9
23
1,889.7
25
205.3
13
Total
Monitored
4,535.1
3,214.5
6,255.4
5,705.1
4,993.1
7,684.0
1,544.2
Source: EPA (1989c).
7-45
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7.5.2 Sewage Sludge
During wastewater treatment, some pollutants are partitioned from wastewater to
the sewage sludge. Reducing pollutant concentrations in the Effueht of a wastewater
treatment plant can reduce pollutant concentrations in sludge and expand the range of
potential disposal options. Currently, several disposal options are available to POTWs,
including landfilling, incineration, and beneficial reuse (i.e., land application). Landfilling is
the most common sludge disposal practice in the U.S. However, this practice will
eventually have to be reduced significantly because of the increasingly limited capacities of
the Nation's landfills. Incineration is another sludge disposal option; however, capital and
operating costs are high, and the ash is often disposed of in landfills. EPA encourages
beneficial reuse of sludge .through uses such as fertilizer or soil conditioner. When
employing reuse options, reducing pollutant concentration becomes particularly important
to minimize the risk of deleterious effects, such as soil contamination, surface water
contamination from runoff, ground-water contamination, and food chain effects.
An attempt to evaluate whether implementation of the pretreatment program has
achieved nationwide reductions in toxic pollutant levels in sewage sludge was hindered by
the lack of a comprehensive national data base containing information on sewage sludge
quality both before and after implementation of the pretreatment program. EPA consulted
three sampling surveys with data on sewage sludge quality (the 40-POTW Study in 1978
[EPA, 1982], the Association of Metropolitan Sewerage Agencies survey in 1987
[AMSA, 1987], and the National Sewage Sludge Survey in 1989 [EPA, 1989b]).
However, these surveys were one-time sampling efforts and were not designed to
determine long-term trends in sewage sludge quality.
For this report, EPA conducted a small analytical exercise to assess the
pretreatment program's effect on sludge quality; the Agency evaluated sludge data from 24
Wisconsin treatrnent plants to determine whether average metal concentrations in sludge
at those facilities had dropped since implementation of their pretreatment programs. Data
'"' '' iii'T . • : " |n I" „ I'll i i I'ii "i ""'" '',1'i'j,'1 '' j,11'1.' i'lj',,,1' iji"',||i j'l,''', 'i'!il!i|! :" i!i|i'',!|i, V ''j"iili''i,'!i'' r^iiiiviil.;1!,.', fy '?iKi!m»''\:lffa!d !»!• I"!!1"*' "x.r'.i'i'ijj 'mill:!,'!!1' ilyi.".!1 '"i'«. •.,»!!'! nil' »|lll'i»"w l'l'"|' ^l":l '"•J'1"'1'
for eight metals were examined; measurements dated from periodic monitoring performed
. " , ! , „' ;'! , " :•' " ' J'ii.J" , f 'i m JIli , i ' •! ' .'i1 ,,"!, '"J',iS»!"„ II liiiW'"I, I,: III1 llPTiBi,IfFli'lIU!1",ir"."•' ^!_-"»' U_'S %!i W 4 "^
since 1977, although the number and timing of measurements available for each plant
varied. To assess differences in pollutant levels before and after pretreatment, data at
each facility (and for each metal) were split into two 'groups, corresponding:lo the official
date on which a pretreatment program was approved for that pQTW. Such a division only
approximates the actual implementation of pretreatment since, at some facilities, a startup
7-46
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phase was necessary. The changeover points used represent the best information
available at the time of analysis, however.
EPA divided the sludge data into two groups (one before the POTW began its
pretreatment program and one after), computed statistical means on each metal at each
facility, and ran statistical tests to identify any significant differences between the mean
concentrations before and after pretreatment.7 Table 7-11 indicates the results of these
tests and shows the extent of significant increases and decreases over time. As the table
illustrates, 21 of the 24 treatment plants experienced significant reductions in
concentrations of at least one metal in their sludges after pretreatment program approval;
10 plants significantly reduced their concentration of at least four pollutants in their
sludges. Seventeen plants experienced significant reductions in lead and 13 plants in
chromium. Fourteen of the 24 facilities showed significant decreases in average total
metal concentrations.
Numerous other POTWs nationwide have reported pollutant reductions in their
sewage sludge after implementing pretreatment requirements; Table 7-12 presents
information reported by 22 POTWs. These POTWs reported that metal concentrations in
their sludges were reduced for one or more of the following metals: cadmium, chromium,
copper, nickel, lead, silver, mercury, and zinc. Reductions ranged from a low of 6 percent to
a high of 100 percent, which occurred at two POTWs. Four POTWs reported that they
reduced loadings to sludge of at least two metals by more than 90 percent. .
Figure 7-7 shows pollutant loadings in sludge for 10 metals at one case, study, the
Pocatello POTW, from January 1983 to August 1990. As can be seen from this figure,
pollutant loadings varied from sample to sample and from year to year. In general, half of
the metals—nickel, chromium, arsenic, lead, and zinc—showed decreasing trends. For the
other five metals, data either indicate an increasing trend or are not conclusive in
establishing a trend. This suggests that Pocatello has not significantly reduced its
loadings of toxic pollutants to sludge.
7. The statistical test performed was the t-test.
7-47
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Table 7-11. Changes in Mean Pollutant Concentrations Before and After
Pretreatment in the Sludge of 24 Wisconsin Treatment Plants (since 1977)
Treatment Plant As
Green Bay
Appleton
Beloit 4-
Brookfield t
DePere
Eau Claire 4-
Fond du Lac
Madison 4-
Manitowoc 4'
Milwaukee
Jones Island
Milwaukee
So. Shore
Oshkosh
Racine T
Sheboygan T
Wausau
West Bend
Neenah Menasha
Watertown
Kenosha
So. Milwaukee
La. Crosse
Isle la Plume
Waukesha
Janesville
Heart of
the Valley
Cd
4
4
4
4
4
"
4
4
4
4
t
4
Pollutant
Cr Cu Hg Ni
4
4 4 .
4
T . t
4 ;' t
4» 4» ' ^
4 i
t 4-
4 4.
" *
4 44
4
4
4 4
4 .. • I
t • t
t
4-4 4
44, 4
t i
4 4
s* ^ *Y
4 t t
Total
Pb Zn Metals
4 4
4
4 4
t t t
4 4
4 4
4 4 4.
44
\L* • *^ ^' x
4
4 4-
I
4
4 t
4' '
4 I 4.
t 't
t
4 4 4-
44 4
4 4-
4 4
4 4
4 = Statistically significant decrease in mean concentration, jx.05.
T = Statistically significant increase in mean concentration, p<.05.
7-48
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'Table 7-12. Examples of POTWs Demonstrating Reductions in Loadings
of Metals in Sludge
POTW
(actual flow)
Holly, MI
(0.8 mgd)
Bowling Green, KY
(5 mgd)
Pocatello.ID
(7 mgd)
Springettsbury Township, PA
(8 mgd)
St. Charles, MO
(8.97 mgd)
Largo, FL
(10.4 mgd)
Altoona, PA
(12 mgd)
Fort Collins, CO
(13.5 mgd)
Source*/
Years
B/84-89
B/81-89
B/85-88
A/81-90
B/86-88
B/85-88
C/85-89
C/84-89
Reported Reductions in
Loadings to Sludge
(Est.)
Zn-24%
(Est.)
Zn-97%
Cr - 72%
Cd-91%
Pb-90%
Ni - 100%
Cu - 88%
(Est.)
Cd-57%
Cr-67%
Cu-42%
Pb-36%
Ni - 56%
Zn-45%
Cu-41%
Zn-59%
Pb-69%
*Cr-65%
Hg-23%
Ni-23%
Cr-63%
Cu - 17%
Pb - 32%
Mir 6%,
Zn-24%
Cd-100%
Cu-29%
Pb - 50%
Ni-94%
Cu -60%
Zn-67%
Pb-23%
Cr-94%
Cd-89%
Cu-35%
*Key to sources:
A = EPA (1989c).
B = EPA (1990b).
C = EPA (1990d).
7-49
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Table 7-12. Examples of POTWs Demonstrating Reductions in Loadings
of Metals in Sludge (continued)
POTW
(actual flow)
Albany, GA
(15 mgd)
Muncie Sanitary District, IN
(17.5 mgd)
Springfield, OH
(19.9 mgd)
Aurora Sanitation District
(Oswego), IL
(22,8 mgd)
Harrisburg, PA
(24 mgd)
Cedar Rapids, IA
(34.15 mgd)
Unified Sewerage Agency
(Hillsboro), OR
(38.3 mgd)
Cobb County, GA
(66.83 mgd)
Source*/
Years
A/83-87
B/73-89
B/84-89
B/85-90
A/87-89
A/82-88
A/85-89
B/85-88
Reported Reductions in
Loadings to Sludge
Cd - <50%
Cr - 99%
Cu - 99%
Pb - 98%
Ni-99%
Zn-94%
Pb - 96%
Cd-79%
Cr - 79%
Cu - 53%
Pb - 87%
Ni - 50%
Zn - 77%
Cd-96%
Cr-92%
Cu - 50%
Mn - 72%
Ni r 78%
Pb - 47%
Zn - 56%
CN - 75%
Cd - 42%
Cu - 27%
Cr - 42%
Zn - 26%
(Est.)
Cd-57%
Cu-52%
Ni-75%
(Est.)
Cd - 54%
Pb - 38%
Cr - 1%
Zn - 9%
Cr - 90%
*Key to sources:
A « EPA (1989c).
B » EPA (1990b).
C « EPA (1990d).
7-50
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Table 7-12. Examples of POTWs Demonstrating Reductions in Loadings
, of Metals in Sludge (continued)
POTW
(actual flow)
Louisville & Jefferson
Counties, KY
(97.9 mgd)
Fort Worth, TX
(105 mgd)
METRO Seattle, WA
(156 mgd)
Columbus, OH
(157.9 mgd)
Milwaukee Metro, WI
(190 mgd)
Miami-Dade, FL
(247 mgd)
Source*/
Years
C/Unknown
B/82-89
C/81-89
A/85-86
A/86-87
A/87-88
C/80-89
A/88-89
Reported Reductions in
Loadings to Sludge
Total Metals - 70%
Cd-83%
Cr-74%
Cu-54%
Pb-68%
Ni-25%
Zn-79%
Cd - 38%
Cu-56%
Pb - 46%
Cd-68%
Pb-34%
.' Cr-41%
Cd-56%
Pb-38%
Cr-48%
Cd-23%
Pb-21%
Cr - 18%
Cd-85%
Three Treatment Plants
Ni - 81%, 41%, 20%
*Key to sources:
A = EPA (1989c).
B = EPA (1990b).
C = EPA (1990d).
7-51
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7-53
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7.3.3 Worker Health and Safety
The pretreatment program's role in reducing potential POTW worker health hazards
associated with toxic industrial discharges cannot be evaluated properly since currently
available data are inadequate. While no data base addresses worker injuries attributed
solely to industrial discharges, numerous incidents of POTW worker injuries due to such
discharges are reported in the literature. As discussed in Chapter 6, these incidents
typically involve severe effects on one or two individuals by a one-time discharge of highly
concentrated toxic substances or less severe symptoms of a chronic nature exhibited by a
larger group of workers. The literature does not provide sufficient data showing that the
• , '.• '„ i , 'i >. ' , I I I 111 I - ", nlll'Jii: #1' ilRin f'i ii''"!'! •' V • f] ,«• ,• i:"'"!', i A»iV'^&' i '» l! "iliis,: ,' J'1',' .'"',,! ii li' I"!: .id ii'" ill "ii'ili in!,," IP1!' :i' 'l;i 'toll!"'«"' •'!! • ,,«,iii ••" 'L'n'J! 'Pi1 lllll'i ii!J
rate of incidents has increased or decreased over the life of the pretreatment program. The
; '«»''.!• • i .'" '•"• ' i i I I ' II11," tmyfS l*''^1^J>-:'1!^:™*»^';;r1';»i-';>.V';'i:i-~^ *«*,&••*$& »i;i
pretreatment program has been used to implement solutions when problems have
occurred, however. In addition, the recently promulgated prohibition against discharges of
pollutants that result in toxic gases, fumes, or vapors that would cause acute worker
health and safety problems is expected to provide increased protection of worker health
and safety. EPA is now developing guidance on this issue.
7.3.4 Air
'.,'•'•• i ' '•'' " ' •' ''" '.; > ! j i I I ' r I III I Ml 111
Little information exists on the nature and volume of toxic pollutants released to the
air from POTWs (see Chapter 6). However, data presented in Chapter 3 suggest tha;t
industrial users are predominantly responsible forme discharge ofvolatileJ compounds into
*the sewer system. Recent development, implementation, and enforcement of control on
industrial discharge of volatile organics is thought to have reduced the quantity of the
compounds in the sewer system. Despite the lack of empirical assessment of such
reductions, it is possible to estimate reductions on a theoretical basis, based on
assumptions of pollutant loadings with and without industrial pretreatment: Such an
approach was taken in previous studies (e.g., Pretreatment Regulatory Impact Analysis
and DSS) to forecast reductions in toxic pollutants expected after industrial compliance
with categorical standards. For example, EPA expects the categorical standards for the
Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) industrial category will
reduce discharges of volatile and ignitable/reactive compounds at OCPSF facilities from
1,667 million kilograms per year to 3 million kg/yr (DSS). The promulgation of the
standards for the pesticides industries is expected to reduce discharges of volatile and
ignitable/reactive substances from 1,085 million kg/yr to less than 1 million kg/yr. In
addition, compliance with the categorical standards for total toxic organics in six industrial
categories and the implementation of solvent management plans in a number of industries
7-54
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are expected to reduce discharges of volatile and ignitable/reactive substances in the
sewer system even further.
7.4 FINDINGS
The following observations summarize principal findings on the effectiveness of the
existing prefreatment program.
1. Pretreatment program requirements are currently being implemented by 1,442
local control authorities at 2,015 wastewater treatment plants and by five States
at 314 wastewater treatment plants. Another 100 local programs, covering 113
plants, are currently being developed. These pretreatment programs and their
POTWs are collectively responsible for over 82 percent of the Nation's municipal
wastewater treatment capacity; they receive the vast majority of all industrial
discharges to POTWs in the United States.
2. EPA Regions and States have been successful in identifying those POTWs
where receipt of industrial discharges makes pretreatment a necessity.
However, 147 POTWs without pretreatment programs are reported to receive
more than 50 percent of their flow from industrial sources. The universe of
pretreatment POTWs will continue to undergo expansions and contractions as
new POTWs enter the program and others are found not to require continued
implementation of programs.
3. Enforcement of local limits and categorical standards is the primary means by
which POTWs ensure that environmental standards and criteria are met. Local
limits are driven by existing environmental standards and criteria, which, in turn,
drive NPDES.and other permit limits. The lack of environmental standards or
permit limits for many toxic pollutants discharged by POTWs may restrict the
development of local limits for these pollutants.
4. Many more toxic pollutants, particularly toxic organics, are discharged by
categorical and other industrial users than are regulated by either national
categorical standards or local limits. In addition, relatively few NPDES permits
impose chemical-specific limits on POTWs' discharges of toxic pollutants.
Recent changes, to the General Pretreatment Regulations may increase the
number of pollutants of concern that are regulated by POTWs.
5. Measurements of programmatic implementation by EPA, States,1 and POTWs
indicate a program in which great progress has been made. About 70 percent of
the 1,442 pretreatment POTWs have been audited or inspected within the past
year. Based on information obtained from audits and inspections, about 84
percent of the 30,000 SIUs discharging to these POTWs have been issued
control mechanisms. In addition, substantial P'OTW efforts have been directed
towards inspection and sampling activities. However, significant deficiencies in
program implementation by POTWs are apparent, such as issuing inadequate
permits, applying categorical standards inappropriately, and failing to take
effective enforcement actions (as evidenced by the high percentage of SIUs in
SNC). Specific programmatic implementation issues have surfaced, such as the
need for POTWs to develop technically based local limits, for EPA to establish
7-55
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national standards for toxic pollutants (particularly organics and nonpriority
pollutants), and to strengthen enforcement of all program requirements, to
ensure that POTWs are fully implementing their pretreatment programs and that
industrial users are complying with all pretreatment standards and requirements.
6. Local implementation allows the program to be tailored to individual
environmental concerns. In contrast to state-run programs, EPA believes that
local programs generally regulate more noncateg'bncal industries, have
established local limits designed specifically to prevent pass through and
interference, and conduct more frequent monitoring. However; local
implementation has some disadvantages; standards may not be uniform, and
similar IUs may be regulated differently by different POTWs.
7. A lack of comprehensive environmental data makes it difficult to evaluate the
pfogram*s effectiveness in achieving the goalsof "the" CWAV 'However,'evidence'
from various data sources suggests that the pretreatment program has reduced
the discharge of toxic pollutants to POTWs and the environment. In cases were
site-specific environmental data exist, EPA found that many POTWs have
documented significant pollutant reductions in influent, effluent, and sludge.
8. A general lack of data on organic concentrations in PQTW influents and effluents
makes it very difficult to characterize the effectiveness of pretreatment'in
controlling the discharge of these chemicals from industry and the effect that
pretreatment has had on reducing the discharge of these chemicals from POTWs."
7-56
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REFERENCES
Association of Metropolitan Sewerage Agencies Sludge Survey Data. 1987. Washington,
DC: Association of Metropolitan Sewerage Agencies. :
/ . ' '
International Joint Commission. A Review of Presentment Programs in the Great Lakes
Basin, 1989. Windsor, ON: international Joint Commission.
U.S. Congress. House Conference Report. 95th Cong., 1st sess., no. 95-830.
U.S. Environmental Protection Agency. 1991. Supplemental Guidance on the
Development and Implementation of Local Discharge Limits Under the Pretreatment
Program. Washington, DC: Office of Water Enforcement and Permits.
U.S. EPA. 1990a. Memorandum from Richard Kozlowski, Enforcement Division Director:
Review of Fourth Quarter and End-of-Year Performance.
U.S. EPA. 1990b. Pretreatment Excellence Awards Applications. Washington, DC:
Office of Water Enforcement and Permits, Permits Division.
U.S. EPA. 1990c. Status Report: State of Compliance With CWA, Section 303 (c) (2) (B)
as of February 4, 1990. Washington, DC: Office of Water Regulations and
Standards.
U.S. EPA. 1989a. FY1990 Guidance for Reporting and Evaluating POTW Noncompliance
With Pretreatment Requirements. Washington, DC: Office of Water Enforcement
and Permits.
U.S. EPA. 1989b. National Sewage Sludge Survey. Washington, DC: Office of Water
Regulations and Standards. .
U.S. EPA. 1989c. Pretreatment Excellence Awards Applications. Washington, DC:
Office of Water Enforcement and Permits, Permits Division.
U.S. EPA. 1989d. Report to Congress Water Quality Improvement Study. Washington,
DC: Office of Water Regulations and Standards.
U.S. EPA. 1986. Report to Congress on the Discharge of Hazardous Wastes to Publicly
Owned Treatment Works. Washington, DC: Office of Water Regulations and
Standards. EPA/530-SW-86-004.
U.S. EPA. 1982. Fate of Priority Pollutants in Publicly Owned Treatment Works.
Washington, DC: Office of Water Regulations and Standards.
U.S. General Accounting Office. 1989. Improved Monitoring and Enforcement Needed for
Toxic Pollutants Entering Sewers. GAO/RCED-89-101.
Wu, Teng-Chung, Eric T. Hsiang, Philip Mellen, Scott Stephens, and Brian T. Bishop.
1989. "Implementation of Pretreatment Programs in the San Francisco Bay Area."
Proceedings of Industrial Session Annual Conference of Water Pollution Control
Federation.
7-57
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,,' h * •«
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8. EVALUATION OF ALTERNATIVE REGULATORY STRATEGIES
This chapter evaluates alternative regulatory strategies for pretreatment of toxic
pollutants as called for by Congress in Sections 519(a)(4)-(6) of the Water Quality Act
(WQA) of 1987. Specifically, Congress directed the U.S. Environmental Protection Agency
(EPA) to study: >
(4) Possible alternative regulatory strategies for protecting the operations of
publicly owned treatment works (POTWs) from industrial discharges, and
the extent to which each such strategy identified may be expected to achieve
the goals of this Act
(5) For each such alternative regulatory strategy, the extent to which removal of
toxic pollutants by publicly owned treatment works results in contamination
of sewage sludge and the extent to which pretreatment requirements may
prevent such contamination or improve the ability of publicly owned
treatment works to comply with sewage sludge criteria developed under
Section 405 of the Federal Water Pollution Control Act
(6) The adequacy of Federal, State, and local resources to establish, implement,
and enforce multiple pretreatment limits for toxic pollutants for each such
alternative strategy. ,
Restated, this statutory mandate requires EPA consideration of alternative strategies
to protect POTWs from industrial discharges. It sets up as key evaluation measures the
extent to which each alternative: (a) achieves the goals of the Clean Water Act (CWA) (see
Table 8-i) and (b) results in or prevents contamination of sewage sludge. Lastly, it requires
an assessment of the adequacy of governmental resources at all levels to develop,
implement, and enforce pretreatment requirements under each alternative.
The scope of this evaluation of regulatory alternatives for pretreatment was also
influenced by the legislative history of Section 519, as well as previous policy studies of the
National Pretreatment Program. As discussed in Chapter 1, Congress did not seek a
fundamental reexamination of the need for pretreatment in specifying EPA's obligations under
Section 519. Instead, Congress directed EPA to consider program improvements that might
better achieve the goals of the CWA.
Alternatives that narrowed the coverage of the National Pretreatment Program (e.g.,
regulating fewer industries, granting large city waivers, reducing the role of local programs to
guidance only) were not considered in light of previous EPA evaluation and congressional
8-1
-------
II If III III
Table 8-1. Goals of the Clean Water Act
A. Explicit Goals
To restore and maintain the chemical, physical, and biological integrity of the Nation's waters
through the policies enumerated below:
• The discharge of pollutants into the navigable waters is to be eliminated by 1985. >
• Wherever attainable, water quality is to be provided for the protection and
propagation of fish, shellfish, and wildlife and for recreation in and on the water by
1983.
• The discharge of toxic pollutants in toxic amounts is to be prohibited.
B. Implicit Policies/Goals
• Where attainable, waters of the United States should be fishable and swimmable.
This ensures clean water and a healthy environment.
• Water is a valuable resource, and no person has the right to use it as a system to
convey or dispose of pollutants. Persons who wish to do so must obtain a permit.
• The regulatory program contains water quality-based provisions that are intended to
be technology forcing. It sets protective standards that must be met by dischargers
regardless of available technology.
• Ensuring the health of the Nation's waters is a responsibility shared by all levels of
government. Although the allocation and specific use of water remains of State and
local concern, the Federal Government has asserted its paramount interest in
ensuring the integrity and stability of this natural resource.
• CWA programs should involve the public in all decisions regarding the issuance of
permits, the enforcement of laws, and the transfer of functions from EPA to State and
local agencies (or changes thereto).
8-2
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review of policy alternatives in the pretreatment Regulatory Impact Assessment, the Three-
City Study, and the Domestic Sewage Study (DSS).
Therefore, policy alternatives pertaining to the status of the Resource Conservation and
Recovery. Act's (RCRA's) domestic sewage exclusion (DSE) were not evaluated.
Reconsideration of the DSE was not undertaken in light of the fact that EPA prepared an
entire report on the topic (the DSS) for congressional review recommending retention of the
exclusion. Moreover, EPA has undertaken several regulatory studies (e.g., 304[m] industrial
evaluations) and recently promulgated the so-called DSS regulation to improve control of
hazardous constituents at POTWs.
Thus, EPA's evaluation focuses on measures to strengthen, refine, or improve toxics
control in the National Pretreatment Program as the common denominator for all alternatives
considered. This chapter first explains the methods EPA used to perform this evaluation,
covering how alternatives were designed, screened, and selected for further analysis based
on Section 519 study findings (Section 8.1). Section 8.2 then details the regulatory
alternatives and supporting options, and Section 8.3 presents qualitative and quantitative
assessments of the alternatives. Given the number of regulatory alternatives and options
considered in this chapter, both Sections 8.2 and 8.3 are organized according to the five
alternatives selected for evaluation. .
8.1 ALTERNATIVE DEVELOPMENT AND SELECTION
EPA's approach to selecting regulatory alternatives for the pretreatment program
involved the following steps: (1) identification of potential alternatives for evaluation,
(2) screening and selection of alternatives based on study findings, and (3) selection of
evaluation methods and data sources. Major aspects of each of these steps are described.
briefly in this section.
8.1.1 Identification of Potential Alternatives
As an initial step in this Report to Congress, EPA convened two focus groups
comprising experts knowledgeable about pretreatment to generate a tentative list of
suggestions for improvements to the pretreatment program. EPA intended these focus
groups to define a wide range of conceivable alternatives early enough in the study to ensure
that data collection was broad enough to encompass all possible choices. The members of
each group were asked to identify key changes that would most improve the National
Pretreatment Program. : • .
8-3
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Table 8-2 lists in random order the results from the focus; groups (by overall subject
area). These cover areas ranging from new types of industrial controls to options
emphasizing environmental objectives, alternatives requiring POTW program improvements,
technical assistance, and program implementation changesT A number of the suggestions
clearly fall within existing regulatory authority (e.g., more aggressive enforcement and more
resources); these are identified in Table 8-2 by hollow squares. Others denoted by
blackened squares would constitute significant new initiatives for the pretreatment program
that would necessitate major regulatory and/or statutory cfianges (e.g., mandatory pollution
prevention for industrial users, corrective action authority in the CWA, and Federal
assumption of pretreatment control authority).
The statutory/regulatory alternatives identified in Table 8-2 were carried forward to the
next phase—screening and selection of alternatives. (The presentation of alternatives in this
document should not be construed as indicating the Administratlbn's policy preferences. It is
purely an evaluation of possible courses of action.)
8.13 Screening and Selection of Alternatives in Light of Report Findings
Initial recommendations for alternatives to the pretreatment program were first
• . . ...i;: ',, . . • • " i, •:,•'.•• fin*'. ;: v' .'.'i :'•• v::
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Table 8-2. Initial Suggestions for Improving Pretreatment Program—
Regulatory/Statutory(«) and Nonregulatory (a) Alternatives
Industrial User Controls
• Establish variance system for pollution
prevention
• Promulgate categorical standards for additional
industries and pollutants
Q Develop additional controls for centralized
waste treaters (CWTs)
Regulate contributors to CWTs
Repeal DSE
Make semiannual inspections mandatory
Repeal removal credits
Require zero discharge of all toxics/persistent
toxics
Environmental Objectives/Controls
• Impose minimum requirements on pollutant-by-
pollutant basis applicable to all industrial users
(Ills) (e.g., single concentration-based limit;
eliminate Combined Wastestream Formula, and
mass- and production-based limits)
• Include more stahdards/ljmits in POTW permits
(e.g., sludge, toxicity, water quality limits)
• Pursue integrated multimedia permitting.
Q Improve State water quality standards
• Acquire corrective action authority for
environmental contamination
• Institute toxic surcharges/environmental benefit
fund
• Expand basis for local limits (e.g., beyond
existing pass through/interference definitions to
a direct basis on environmental criteria)
• Standardize information requirements for local
limits approval
• Expand list of Section 307(a) toxics
• Promulgate numerical sludge quality criteria for
all use and disposal options (including co-
disposal)
• Control domestic sources of toxics
POTW Controls
Q Improve operator training and/or certification
requirements for POTWs '
a Institute laboratory certification/audit program
• Require administrative penalty authority
• Require mandatory monthly influent/effluent/
sludge sampling
Q Expand inspection authority
• Evaluate nondischarging POTWs for
development of local programs
Q Establish POTW best management practices
(BMPs), operation, treatment enhancement
• Establish influent antibacksliding policy for
influent quality
• Require civil and criminal penalty authority
Program Implementation
Q Improve oversight of existing State and local
programs
Q Improve uniformity of program administration
and regulation interpretation across all levels
(EPA, States, locals)
Q Identify top 10 POTW permits needing
.modifications
• Remove POTWs as. control authority (Federal/
State control authorities) .
• Make EPA the control authority; POTWs
perform sampling, analysis, inspection, etc.
Q Pursue aggressive Federal/State enforcement
against POTWs
Q Pursue aggressive Federal/State enforcement
against ItJs
• Implement at State level
a Improve followup of POTW inspections/audits
Q Withdraw poor State programs
a Seek more State program approvals
Q Identify all facilities subject to new categorical
standards
a Expand State involvement
• Require regulation (permits) of industries by
EPA. in absence of effective State or local
regulation
• Require lUs to fund program/user fees
a Allow partial POTW programs
• Shift technical responsibilities from POTWs to
industries and approval authorities (e.g., local
limit development) ,
a Make State/EPA enforcement authority
equivalent
• Make pretreatmeht regulations applicable to
POTWs self-implementing (i.e., no need to first
modify permit)
Technical Assistance
Q Obtain more money for all levels
Q Provide more direct technical assistance to
POTWs,(e.g., local limit development)
Q Demonstrate innovative technology for
pretreatment and waste, minimization
Q Increase public education
Key .
Q = Alternative within existing regulatory authority.
• = Regulatory/statutory alternative.
8-5
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• ' «. tvi?,;:-:
Table 8-3. Report to Congress Findings and Alternatives
Study Issue
(chapter)
Report to Congress Findings
Associated Alternatives
Toxic
Discharges to
POTWs—
Chapter 3
Categorical pretreatment standards have
not been developed for several potentially
significant industrial categories.
Data on industrial discharges are
incomplete at local, State, and national
level for Some pollutants and industries.
Industries discharge many toxic pollutants,
some of which are not sufficiently
controlled.
Proven pollution prevention technologies
are available for some industries.
Domestic sources may be significant in
limited situations.
Expand technology-based
controls to other industries
Require more industrial
monitoring
Develop national pollutant
standards for all lUs
Incorporate pollution
prevention into industrial
pretreatment controls
Best professional
judgment (BPJ) limits for
lUs not covered by
categorical standards
Secondary
Treatment
Removal of
Toxics—
Chapter 4
Biodegradation is the only true removal.
POTW removal is highly variable.
POTW removal typically is too variable to
supplant pretreatment.
Certain pollutants end up in sludge, air, or
receiving waters, or they biodegrade.
Extensive monitoring is necessary to
quantify POTW removals.
• Limit removal credits to
pollutants that biodegrade
• Issue zero discharge
standards to lUs for
nonbiodegradable
pollutants
• Require more monitoring to
establish POTW-specific
removals
POTW
Capability
To Control
Toxics—
Chapter 5
Most removal credits have been granted
for nonbiodegradable pollutants.
Comprehensive environmental criteria are
lacking to develop environmentally
protective local limits and assess the
impacts of removal credits.
POTWs have developed some local limits
to control toxics in the absence of sludge
standards and National Pollutant
Discharge Elimination System (NPDES)
limits.
Basis for POTW local limits is variable—
33 percent of local limits have known
technical basis.
Allow removal credits only
for biodegradable pollu-
tants
Allow removal credits only
for pollutants limited in
NPDES permits
Require local limits to
meet environmental
criteria
Base NPDES permits on
environmental criteria
Tighten procedural basis/
establish consistent
technical basis for
developing local limits
8-6
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Table 8-3. Report to Congress Findings and Alternatives (continued)
Study Issue
(chapter)
Report to Congress Findings
Associated Alternatives
Environmental
Impacts—
Chapter 6
Key pathways are:
- Effluent: surface water, sediments
- Sludge: ground water, soils, direct
contact, air
- Incinerator: air, ash
- Volatilization: air
-.' Plant integrity: corrosion, explosion,
worker health and safety.
Standards for discharges/releases are
scattered; implementation is inconsistent
and incomplete.
Significant amounts/concentrations of
persistent and other toxics are discharged
by POTWs, with known potential for,
adverse impacts.
Data useful in assessment of impacts were
collected for many purposes and are not
entirely adequate for assessment. Data on
sludge, air, human health, collection
systems are much less extensive than for
surface water.
Monitoring data to measure impacts are
lacking.
Criteria for assessing impacts are available
for only a limited number of pollutants
• Expand priority pollutant
list
• Develop criteria and
standards for all receiving
media
• Establish mandatory
NPDES permit limits for
releases to all media
• Require corrective action
for environmental contami-
nation
• Increase ambient environ-
mental monitoring and
reporting
Program Effec-
tiveness—
Chapter 7
• Regulation of categorical industrial users
and significant industrial users at nonpre-
treatment POTWs is incomplete and
inconsistent.
• POTWs can be effective regulators but face
political and resource obstacles.
• It is difficult to assess environmental effec-
tiveness at the national level, but
pretreatment POTWs have reduced toxic
pollutant loadings and adverse
environmental impacts.
• Incomplete environmental criteria hamper
environmental evaluation and limit
development of requirements; existing
criteria are not incorporated adequately.
Expand Federal authority
to regulate lUs directly
Emphasize inclusion of
environmental criteria for
toxics:
- In NPDES and sludge
permits
- As basis for local limits
Require more IU, POTW,
and environmental
monitoring
8-7
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• The pretreatment program's dependence on environmental criteria to control
discharges to surface water, air, and sludge creates an integrated, multimedia
approach to the control of toxic discharges. Regulatory programs concerned with
surface water, sludge, and air quality, as well as worker health and safety, ultimately
play an important role in thesuccessof'the'pretreattnenf^0^^- manycriteria and
standards under such programs drive the numeric limits in NPDES permits and
ultimately are incorporated into local limits.
• Lack of national data makes it difficult to evaluate the impacts of toxic pollutants on
the environment and the program* s effectivenessi'fa'controflihg these impacts. While
there is no "ideal" data base that provides accurate, comprehensive information, the
expansion of information at the POTW, State, and Federal level on three basic
subjects—IU discharges, POTW operations, and environmental effects—is key to
enhanced program development, implementation, and enforcement.
In light of these central findings and given the number of alternatives and refinements
provided in Table 8-3, the alternatives were reorganized into four procedural aspects of the
pretreatment program that may warrant improvement—national indirect discharger controls,
POTW-specific source controls (including removal credits am!'local' limits)j environmental
controls, and monitoring. Additionally, an alternative shifting governmental administrative ,
responsibilities for toxics control actions to States and the Federal Government was carried
forward to address potential issues about local program5 a3'e(^.'acy"ah'd capability. This
organizational scheme is broad enough to capture the diverse alternatives to be considered,
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but simple enough to support differentiation and evaluation..
I, ill!»' ,»l lit! I*1,' lUi. II1!!!1: i IP1! I f'Plil *!",'!,!,' .i"l'' 'ill<: !l"'!' II!11" !!" IT WUli,' Ji'l "til i:, ! 1,1' „,',!,"; IMP:, '« I II i lir i Illi"! 4
III I I I III I 1 I ' I I I I II II Hi II
Table 8-4 presents the revised alternatives (and associated options for each) selected
for final evaluation in this Report to Congress. As can be seeru EPA c^med forward five
types of regulatory improvements for evaluation: strategies to further reduce industrial toxics
loadings at both the national and local levels (alternatives 1 and 2, respectively);
mechanisms to emphasize environmental protection at pretreabnent POTWs (alternative 3);
approaches to gather more information on toxics discharges and POTW performance
(alternative 4); and changes in responsibilities for administering the program (alternative 5).
Within each of these major alternatives are a number of optional approaches for attaining the
broader goals of the alternatives. (To distinguish between the major alternatives and
supporting options, the terms alternative and option are always used distinctly.) Options
within an alternative may vary in .terms of the regulatory technique, the target, or the outcome
sought. For example, as shown in Table 8-4, options within alternative 1 reflect different
approaches to reduce industrial loadings at the national level by varying the basis for
coverage (e.g., technology-based, pollutant-based, zero discharge) and scope of coverage
8-8
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Table 8-4. Overview of Regulatory Alternatives and Options
1. Enhance national pretreatment standards
1.1 Develop categorical standards for 304(m) industries and revise existing standards,
including regulation of additional pollutants
1.2 Integrate pollution prevention technologies into all categorical pretreatment
standards where practicable ,
1.3 Promulgate national nondomestic pretreatment standards on a pollutant-by-
pollutant basis to cover all nondomestic dischargers (including commercial
facilities)
1.4 Issue zero discharge standards for industries discharging persistent non-
biodegradable toxic pollutants
• - 1.5 Prohibit the discharge of certain products/substances from households to sewers
(household hazardous waste control)
2. Improve/restrict site-specific toxic discharge standards
2il Limit removal credits to pollutants that are biodegraded in municipal systems
2.2 Stiffen removal demonstrations required to qualify for removal credits
2.3 Establish mandatory local limits development requirements (e.g., pollutants, use of
actual data, review procedures) .
2.4 Mandate that local limits be developed to meet all applicable environmental criteria
3. Enhance environmental controls on POTWs
3.1 Promulgate environmental criteria for all POTW receiving media (receiving water,
air, sludge, sediment)
3.2 Require inclusion of toxic limits in permits for all pretreatment POTWs, covering all
wastestreams (air, water, sludge)
3.3 Require corrective action at POTWs where environmental monitoring reveals
releases and/or contamination
8-9
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Table 8-4. Overview of Regulatory Alternatives and Options (continued)
4. Expand pretreatment monitoring requirements
4.1 Expand significant industrial user monitoring requirements
Increase effluent monitoring for all toxic/hazardous pollutants
Conduct toxicity testing or inhibition testing on industrial discharges
Require prohibited discharge monitoring
4.2 Expand POTW wastestream monitoring requirements
• Increase frequency and pollutants covered in influent, effluent, sludge
sampling/analysis
• Increase toxicity testing
4.3 Require POTWs to monitor ambient receiving environments
• Monitor ambient water quality sampling upstream and downstream from all
POTW outfalls .
" • Monitor air monitoring onsite and downwind
• Monitor sediment upstream and downstream
• • Monitor ground water where pipe exfiltration, injection, or leaching from unlined
lagoons or sludge ponds may occur
5. Shift administrative burdens/responsibilities in National Pretreatment Program
5.1 Shift more responsibilities, such as category determinations and enforcement
responsibility, from control authorities (POTWs) to approval authorities (States
and EPA Regions) responsibility
I , ' | , '
5.2 Centralize program—expand Federal/State authority to regulate industrial users
8-10
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(e.g., categorical industrial users [CIUs], all significant industrial users [SIUs]) of the
proposed standard. Section 8.2 describes in greater detail the alternatives and associated
options.
8.1.3 Methods and Data Sources for Alternatives Evaluation
In evaluating alternatives for the National Pretreatment Program, EPA assessed each
both qualitatively and quantitatively. As a starting point, each alternative (and each option
within each alternative) is defined in Section 8.2. The potential benefits of each alternative
are compared with the goals of the CWA and its impact on sludge quality, as called for in
Section 519. Then, a more quantitative evaluation is performed for each option addressing, to
the degree possible, the number of affected parties, compliance costs, government
administrative .costs, and expected results. Finally, the adequacy of Federal, State, and local
resources required to establish, implement, and enforce each alternative is presented.
The data used for this assessment are drawn from report findings, Agency resource
estimates, and BPJ where estimates were otherwise unavailable. An underlying caveat, to
this alternatives evaluation is that it is speculative, relying on judgment to predict the future
effects and outcome of alternatives. Given this degree of uncertainty, quantitative estimates
are intended to indicate the direction and relative magnitude of a change or impact, but are not
offered as precise values.
8.2 DETAILED CHARACTERIZATIONS OF REGULATORY ALTERNATIVES
This section presents a more detailed description of the regulatory alternatives
proposed as potential improvements to the existing National Pretreatment Program. Each
alternative addresses a major functional component of the existing program. The alternatives
can be considered discrete or complementary strategies for program improvement that are, for
the most part, not mutually exclusive. Moreover, options within each alternative may be
selected independently or in conjunction with others. Key linkages among alternatives are
also highlighted in the following descriptions.
8.2.1 Alternative 1: Enhance National Pretreatment Standards
Options within this regulatory alternative would reduce toxic loadings to POTWs as a
result of EPA-promulgated national, pretreatment standards. Implicit in this alternative is the
premise that toxic discharges from industries at many POTWs remain too high despite the
prohibited discharge standards, categorical standards for existing and new sources, and local
limits currently in place. This - alternative further presumes that EPA is best equipped to
8-11
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address some subset of these, unregulated or underregulated sources of toxics because of the
Agency's experience, resources, and political will. This option would also be supported by
perception of the need for national consistency and equity.
As may be observed in Table 8-4, the options within this alternative vary with respect
to the specific source to be controlled—additional new categorical industries (option 1.1),
selected existing categorical industries (options 1.2 and 1.4), all significant industries and
commercial facilities (option 1.3), and domestic sources (option 1.5). Many of the source
confirol options also vary with respect to the basis for the new standards. Thus, options 1,1
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and 1.2 call for EPA promulgation of technology-based standards, with option 1.1 relying on a
traditional approach and option 1.2 mandating consideration of pollution prevention
approaches as the basis for numerical standards in establishing industrial water pollution
controls. Option 1.3, calling for national pretreatment standards on a pollutant-by-pollutant
"basis, might be implemented using treatment plant inhibition levels or operational parameters
as the basis for limits. Lastly, options 1.4 and 1.5 rely on absolute bans as the basis for
standard setting, requiring EPA action to determine the unacceptable pollutant parameters.
These options are not mutually exclusive; rather, they could be combined to achieve the
magnitude of incremental pollutant reductions desired in the most efficient manner. Option
1.1 targets the additional industries being investigated as a"result of the DSS and the 304(m)
process. As discussed in Chapter 3, these industries include machinery manufacturing,
Pharmaceuticals manufacturing, hazardous waste treatment, and industrial laundries. Option
1.2 would reduce loadings by identifying industries where pollution prevention technologies or
processes would reduce or eliminate pollutant discharges. This would build upon current
Agency practice of incorporating pollution prevention practices into BAT. Industries would be
targeted according to the feasibility of, and opportunities for, pollution prevention, in addition
to the mass of pollutants that would be reduced. This would tie into other major EPA
environmental initiatives.
Option 1.3, with its emphasis on pollutant-specific rather than industry-specific
pretreatment standards, would seek to simplify national standards to assist POTW
implementation and enforcement and to overcome common complaints over complexities
associated with the current pretreatment program (e.g., industrial category determinations,
production-based standards, and the combined wastestream formula). Under this option,
categorical standards for specific pollutants would gradually be supplemented by uniform
pollutant-specific standards. This option would cast the widest net with respect to source
8-12
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control obligations, but would necessarily not account for economic or technological
achievability by industrial source categories.
Option 1.4 is distinct in its realization of one of the fundamental goals of the CWA:
elimination of the discharge of toxic pollutants. The specific rationale for controls under this
option is that toxic pollutants that are not degraded by wastewater treatment plant processes
but merely transferred to another medium (e.g., air, sludge, sediment, or soils) and that
persist in the environment for prolonged periods should not be discharged to the Nation's
waters if they pose a significant environmental risk (see discussion in Chapters 4 and 6).
Such a proscription is consistent with the WQA's objectives and is the basis for cross-media
pollution control initiatives under the Great Lakes Water Quality Agreement.
Finally, option 1.5 would adopt at a national -level what some municipalities have
undertaken locally: namely, system-wide controls on household hazardous or toxic wastes.
Such programs may include public education on desirable waste disposal practices, disposal
programs for domestic hazardous wastes, bans on the use or dumping of certain
commercial/household products (e.g., liquid drain cleaners), promotion of less toxic consumer
products, and enhancement of corrosion control programs for municipal drinking water
systems. As Chapter 3 indicates, control of domestic sources of toxics has been shown to be
effective in some pretreatment cities where a major share of toxic loadings comes from
residential wastewaters. Domestic controls wduld be appropriate at the national level were
it to be shown that industrial categorical standards and local limits were broadly insufficient
; to enable POTWs to comply with municipal sludge criteria or more pervasive toxics limits in
their NPDES permits.
8.2.2 Alternative 2: Improve/Restrict Site-Specific Toxic Discharge Standards
The underlying premise of alternative 2, like that for alternative 1, is that further
reductions in loadings are necessary to protect POTWs and the environment. However,
contrary to the preceding alternative, options within this alternative tighten control of toxic
discharges at the local, rather than national, level, relying on local expertise and proximity to
develop controls. Within this alternative are two distinct types of options: options 2.1 and
2.2 limit the availability of removal credits; options 2.3 and 2.4 strengthen local limits.
Option 2.1 would restrict removal credits availability to pollutants shown to be
biodegraded in POTW wastewater treatment plants. Many pollutants are volatilized,
partitioned to sludge, or passed through to receiving waters without destruction or
' . " 8-13 '
-------
degradation. Option 2.1 would preclude POTW relaxation of national categorical standards
for any pollutant that was not actually degraded within the POTW treatment plant,
independent of environmental effect of the release or discharge. This option is a companion to
option 1.4, which calls for the elimination of the industrial discharge of persistent toxics.
Option 2.2 would require more rigorous demonstration of removals for POTWs to qualify
for removal credits. The most recent removal credits regulations required a minimum of 12
individual samples per year and allowed the use of historical data to demonstrate POTW
removals. Option 2.2 would require an intensification of removal monitoring to support
removal credits applications. For evaluation purposes, it is assumed that POTWs would be
required to monitor continuously over some predetermined period (e.g., daily measurements
over 4 separate months representing four separate seasons) to determine consistent removal
and that historical data could not be used.
It should be noted that the scope of both removal credits options may be relatively
narrow, given the small number of POTWs that have applied for and qualified for removal
credits to date. These options may have little effect in reducing current toxic loadings, but
they would prevent prospective increases that might result with the return of removal Credits
after EPA promulgation of the sludge criteria.
" • i " •', ;',i,i,, ,, • "; i»i i i n i ii i H j i i ii ii i (
Options 2.3 and 2.4 would reduce toxic discharges by POTWs by improving local limits.
They recognize that some municipalities have been successful in addressing local problems
but seek to make local toxic discharge limitations more consistent and widespread across all
pretreatment POTWs. In particular, these options would strengthen the role of
environmental objectives in the development of local limits by POTWs. To this end, they
depend on aggressive promulgation of Federal environmental criteria, standards, and permit
limits, as called for in alternative 3. Also implicit in these alternatives is that the cooperative
intergovernmental approach to promulgation of categorical standards and local limits remains
desirable. Equitable national controls with local polishing'" is seen as "a" potential regulatory
strategy that would be enhanced by enumeration of more concrete regulatory guidelines and
objectives.
Option 2.3 would codify the essential components of EPA's Guidance Manual on the
Development and Implementation of Local Discharge Limitations Under the Pretreatment
Program (EPA, 1987) and provide precise regulatory guidelines on such components as
(1) POTW requirements to consider certain pollutants for local limits and specifying methods
8-14
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to be used for identifying others; (2) the specific technical bases required for limits
development; and (3) data requirements to support local limits (i.e., POTW-specific versus
national or other default removals data). Presumably, this option would have minimal effect
on those pretreatment POTWs that have been found by program audits to have technically
based local limits (about 34 percent of pretreatment programs,-nationally, have some
technically based local limits), but would provide clearer direction and technical support to
municipalities that should have already developed technically based local limits, but failed to
do so.
Option 2.4 broadens the legal basis for local limits. The current pretreatment
regulations link local limits principally to pass through and interference, which in turn are
based on violations of NPDES permit conditions. This option would tie local limits tp all
environmental criteria (e.g., water quality, sludge, and air quality criteria, standards, NPDES
permit limits, and worker health and safety criteria) relevant to POTW discharges. This
change would require municipalities to consider all wastestreams and media in evaluating the
need for and developing local limits. This option also presumes a major effort by EPA/States
in development of guidance and training, which would explain methods for application of the
criteria to site-specific situations. This option corresponds to the environmental monitoring
and control options (option 4.3 and options 3.1-3.3, respectively).
A variant of options 2.3 and 2.4 would involve issuing guidance to assist municipalities
in setting local limits for nonconservative and reactive compounds. Issuing guidance and
conducting followup, targeted training recognizes the effectiveness of current guidance and
training efforts.
8.2.3 Alternative 3: Enhance Environmental Controls on POTWs .
Whereas alternatives 1 and 2 rely on more stringent source controls to improve local
pretreatment programs, alternative 3 directly strengthens environmental objectives for
POTWs as a means of improving toxic pollutant control by pretreatment POTWs. This
approach relies on one of the program's underlying premises: that POTWs will tighten down
on industrial, commercial, and domestic sources of toxics as necessary to attain
environmental objectives. Local programs are intended to prevent pass through, interference,
and sludge contamination. POTW NPDES permits are to contain water quality-based toxic
limits to protect receiving waters. As a result of the Water Quality Act of 1987, NPDES
permits will increasingly contain toxic limits for sludge disposal. Moreover, POTWs are also
subject to State and local air quality, ground'water, and health and safety regulations.
\ '
8-15 '.'••'•
-------
Nevertheless, implementation of this approach has been slow and, as discussed in
Chapters 5 and 6, few POTWs possess a full complement of environmentalobjectives "tfiat
provide benchmarks for toxics control. The three options in alternative 3 represent different
approaches to improving the integration of environmental measures into the pretreatment
program.
Options 3.1 and 3.2 are integral to each other. Option 3.1 calls for EPA to issue
environmental criteria for pollutants in all POTW receiving environments. This would require
EPA to further develop water quality.criteria, sludge standards (presently underway), and air
quality standards for toxic pollutants. These criteria and standards could serve as the basis
for the mandatory permit limits for all pretreatment POTW discharges, releases, and
emissions envisioned under option 3.2. Alternatively, State and EPA permit writers could
implement option 3.2 using BPJ or technblogy-baseS approaches to derive POTW"
environmental limits.
The data generated as a result of options 3.1 and 3.2 would enable control authorities to
assess the adequacy of environmental protection by pretreatment POTWs. As a corollary to
this option, municipalities might receive greater programmatic flexibility if they were to
achieve consistent compliance with comprehensive environmental limits. It is not the intent
of these options, however, that enhanced environmental controls on POTWs should supplant
either Federal technology-based pretreatment standards or l°ca^ discharge limitations.
Instead, these options would provide environmental standards that would enhance the
effectiveness of pretreatment measures by driving the development of additional local limits.
, .. , • :,i!i '•"'•• ,' '• '/ :' ",.."',..',,,f'i .'!I :?,! V, i • • ,i •'!' 1 >' ^X1 i.?I, iilB! it. WSffiM';!"'(;:;:;"„[',!,> ,U!"!Mi*,"!,:',Sit- S',',!::',:'Kir";.1 t• • Wi!SSKiMiillfl>Lfc
• Option 3.3 is modeled after the corrective action program under RCRA. It would require
approval authority oversight to conduct and evaluate "POTW environmental assessments.
This option is remedial, rather than-preventive, and would require municipalities to correct
environmental problems associated with toxic releases from POTWs to all environmental
media. Option 3.3 would, ^of necessity, depend on the comprehensive; environmental
monitoring called for in option 4.3 and the environmental benchmarks established in option 3.1
and/or option 3.2. Under this option, a pretreatment POTW would monitor all releases and
endpoints associated with toxic discharges. Where monitoring revealed contamination above
applicable environmental criteria, the POTW would be required to initiate corrective
measures (e.g., removal or immobilization of contaminated sediments or retrofitting of sludge
monofills). The controlling premise behind this proposal is that environmental problems
associated with toxic releases at POTWs may not be widespread enough to warrant
•...-• -: ••. ,, "8-16 , ' ; • ..;, •
-------
extensive remedial actions across all POTWs but that where problems do exist they should
be identified and corrected.
8.2.4 Alternative 4: Expand Pretreatment Monitoring Requirements
Alternative 4 consolidates options that would increase the monitoring responsibilities of
industrial users and/or POTWs. This alternative would ensure that more information is
available to control authorities and approval authorities on pollutants present in industrial
discharges, POTW wastestreams, and POTW receiving environments so that impacts
resulting from toxic discharges can be identified and controlled. Options under this
alternative affect SIUs and POTWs.
f
In option 4.1^ SIUs would be required to perform more extensive self-monitoring, testing
their effluents more frequently and for more toxic constituents than is currently required (SIUs
are currently only required to self-monitor semi-annually for pollutants addressed in the
control mechanism). In addition, SIUs would be explicitly required to test their effluents for
whole effluent toxicity and ignitability.
Such an increase in.SIU monitoring would be warranted by evidence, discussed
throughout previous chapters, that neither industries nor POTWs fully know what is in
industrial discharges to municipal sewers. Such testing would allow POTWs, States, and
EPA Regions to make effective regulatory decisions to control toxic pollutants (e.g., through
permitting, local limits development, and enforcement).
Option 4.2 would require pretreatment POTWs to engage in system-wide monitoring of
plant wastestreams (influent, effluent, and sludge), which would give municipalities and.their
regulators more complete knowledge of system conditions, impacts, and contamination from
toxic discharges. Increases in sampling frequency would ensure more accurate data for
removal credits and local limits development activities, and would support other program
implementation and enforcement activities. Toxicity testing would be mandated more often
than the once per 5 years specified in the DSS regulations (40 CFR 122.21 Q] (1)), and would
provide more reliable data on POTW effluent toxicity in light of the high variability associated
with industrial discharges, POTW influent, and POTW removal processes. Results would be
used to adopt more effective toxic control strategies, as well as to regulate POTW discharges
in NPDES permits. Such changes could be implemented through NPDES permit
requirements without any regulatory/statutory changes. Indeed, EPA Regions and States
8-17
-------
have required some POTWs to monitor more frequently (including toxicity monitoring) than is
prescribed by the rules.
The final monitoring option, 4.3, would require POTWs to engage in mandatory ambient
environmental monitoring for all media affected by releases from POTWs. POTWs frequently
have significant effects on their receiving environments. This option would improve
knowledge and documentation of changes across media from POTW operations. While
surface water monitoring occurs at some POTWs on sensitive receiving streams or under
special circumstances (e.g., 301[h] POTWs), it is rare. POTW monitoring of other media and
releases is extremely unusual. Such an option presumes that information at the POTW,
State, and Federal level on the environmental impacts associated with pretreatment POTWs
is inadequate to support such critical decisionmaking for local limits development and
industrial and municipal permitting, among other activities. This option could be linked to the
development of environmental criteria (option 3.1), to environmental permitting (option 3.2),
or to the corrective action option (3.3). Alternatively, environmental monitoring could serve
as a stand-alone option to heighten POTWs' awareness of their environmental effects.
"" ' I ' "lllll'i ill , I ''' '"" M "
A common thread in all monitoring options under alternative 4 is that the National
Pretreatrnent Program lacks comprehensive data on industrial and municipal toxic discharges
sufficient to identify problems, monitor progress, ensure compliance, and evaluate program
effectiveness with a high degree of reliability. The options within the monitoring regulatory
alternative vary with respect to the nature and source of the monitoring information desired
concerning the quality of influent, effluent, and sludge, and the pOTW's environmental impact.
A final monitoring regulatory decision could carry forward one or all of the options presented.
1 ' i'1:1, ln " , . . " I i II
Options 4.1 and 4.2 are currently required in reduced form under the pretreatrnent and
NPDES programs. The frequency of monitoring events included in these options could be
adjusted as necessary to achieve the appropriate staging of sampling events to meet all
regulatory objectives. Option 4.3 is not mandatory at the Federal level except for 301(h)
POTWs, although some States" may require environmental monitoring at POTWs. There is
precedent for such environmental assessments under the CWA, as in the monitoring
1. . ".is1 .. " ,; ,:ii > '. i i i iiiiiii i i in i i i i nn i
requirements for municipalities exempt from secondary treatment under 301(h). Any or all of
these options could also require reporting monitoring results to control or approval authorities
as 'appropriate.
8-18
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8.2.5 Alternative 5: Shift Administrative Responsibilities in the National Pretreatment
Program
Alternative 5 contains two possible administrative changes for the National
Pretreatment Program. Both options represent dramatic departures, from the current role
played by local authorities (POTWs) in the program. Option 5.1 would transfer certain
program responsibilities, such as development of local limits and program enforcement, from
municipalities to approval authorities (approved States and EPA Regions). Municipalities
might retain identification, monitoring, and permitting responsibilities. This realignment of
responsibilities would draw on the greater technical expertise and resources at the approval
authority level, and would provide insulation from local political pressures.
Option 5.2 is a more absolute variant of option 5.1, calling for the transfer of all
pretreatment program responsibilities from municipalities to States and EPA. In essence,
.control of toxic discharges from indirect dischargers would be accomplished by the same
agencies now issuing NPDES permits for direct dischargers.
Option 5.2 would require no changes to State-run pretreatment programs under 40 CFR
403.lO(e). This option would be supported by evidence that POTWs were not effective
regulators of industrial waste dischargers or, alternatively, that State-run pretreatment
programs and regional regulation of categorical industries in nonpretreatment cities had been
particularly successful. . ,.
Obviously, option 5.2 would be mutually exclusive with much of alternative 2, which
stresses improvement of local controls. Otherwise, consideration of alternative 5 and all the
other alternatives can proceed independently.
8.3 EVALUATION OF STATUTORY/REGULATORY ALTERNATIVES FOR THE
PRETREATMENT PROGRAM
This section provides a summary evaluation of the five principal statutory/regulatory
alternatives described in Section 8.2. The evaluation is accomplished by means of a
qualitative and quantitative assessment of each alternative and its respective options.
.Tables 8-5 and 8-6 serve as an organizational framework and guideposts for the discussion.
In evaluating the options, the following factors need to be considered: (1) the cost of
the effort to the private and public sector, (2) the pollutant reductions and environmental
/ .
results achieved, and (3) the practicality of implementing the alternatives. These factors are
8-19
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reflected in Tables 8-5 and 8-6, Appendix D, and the following narrative. A short description
of Tables 8-5 and 8-6 appears below. Following these descriptions, five separate
subsections corresponding,to the five statutory/regulatory alternatives provide a more explicit
explanation of the results summarized in Tables 8-5 and 8-6.
Table 8-5 provides a qualitative assessment of the alternatives (and associated
options) in summary form. It lists the options, their purposes, affected parties, types of
change expected, evidence supporting the alternatives, applicability to ''CWA" goals", effects on
sludge, benefits, and drawbacks.
Table 8-6 provides quantitative information, to the extent available, on each alternative
(and associated options). In addition to identifying the size of the affected universe, it lists
basic assumptions for the quantitative analysis; estimated costs (often expressed in ranges)
to industrial users, the POTW, and Federal and State governments; and results that may
accrue by adopting each of the options. The quantitative estimates provided here are
intended to give a relative sense of the magnitude of change to be expected under a given
option. To estimate the quantitative impacts of each alternative (and option) accurately, a
much more rigorous analysis than was attempted, here would need to be accomplished.
Appendix D summarizes the basis for each quantitative estimate given in Table 8-6.
8.3.1 Evaluation of Alternative 1: Enhance National Pretreatment Standards
This alternative encompasses five optional strategies that would reduce -toxic loadings'
through the promulgation of categorical pretreatment standards. Each option implies the need
for EPA to promulgate categorical standards, for industrial users to comply with those
standards, and for pretreatment POTWs to ensure industrial user compliance with those
standards. EPA promulgates categorical standards in cases where specified industrial
sources discharge significant loadings. Where sources do not present a concern at the
national level, EPA may issue guidance to assist POTW''ope^tors'1''and NPDES permit
writers in fashioning control requirements.
The five options were (1) developing new and revised categorical standards,
(2) incorporating pollution prevention technologies into categorical standards, where
practicable, (3) establishing pollutant-specific effluent standards for persistent pollutants
covering all significant users, (4) incorporating zero discharge standards for persistent
pollutants that pose high risks into categorical standards, and (5) prohibiting the discharge of
certain products/substances from households to sewers.
• " ";' ,' . ; . , " ', 8-32
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The Office of Water is undertaking, or has recently undertaken, initial studies for the
development or revision of several categorical standards. The following steps generally occur
in standards development: (1) writing a preliminary data summary, (2) developing and
analyzing an industry survey, (3) conducting sampling and analysis, and (4) preparing the
categorical standard rulemaking record, including options selection. In general, decisions
usually are made to proceed or not to proceed with a complete rulemaking effort after the data
summary is finished.
Preliminary data summaries vary in cost but can be completed for approximately
$200,000 each, or $3.8 million for the 19 industries. Steps 2 through 4 are far more variable in
cost. Industry surveys are estimated to cost from $300,000 to $2.5 million, sampling from $2
to $6 million, and guidelines development from $1 to $2 million for each industrial category.
Assuming 10 industrial categories are carried through the entire process and 9 more through
the preliminary data summary phase, a total cost estimate for categorical standards
development ranges from $37 million to $107 million. Associated industrial user compliance
costs range from $880 million to $1,700 million. It is estimated that these industries currently
discharge approximately 68.9 million pounds annually and that additional controls may yield
reductions from 50 to 75 percent, or 30 to 51.6 million pounds. EPA is unable to attach a
monetary value to the benefit of these loadings reductions.
Option 1.2 calls for categorical standards mandating pollution prevention (as
practicable) and Option 1.3 would require zero discharge requirements for persistent
pollutants. The standards development process currently considers both pollution prevention
techniques and zero discharge as viable control options. Indeed, categorical standards for
three prominent industrial categories are based on pollution prevention techniques: iron and
steel (flow reduction); organic chemicals, plastics, and synthetic fibers (in-plant process
controls); and petroleum refining (flow reduction). However, the statute does not provide for
preferential selection of either pollution prevention or zero discharge options, although either
pollution prevention techniques or zero discharge may be selected as the basis of the effluent
limitation if available and economically achievable. Even where pollution prevention or zero
discharge are not the basis for selection of effluent limitations, any single industrial user may
use such techniques to meet the prescribed limitations.
As explained in Chapter 3, EPA's Pollution Prevention Information Clearinghouse
includes case studies of voluntary pollution prevention techniques available in 36 separate
industrial categories. A growing number of industrial users-in certain industrial categories,
8-33
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such as metal finishers/electroplaters, are turning to pollution prevention techniques to reduce
environmental protection expenditures. Indeed, some electroplaters are now making use of
"closed-loop" technologies.
In reviewing existing categorical standards and developing new categorical standards,
the Office of Water could establish a policy that pollution prevention techniques constitute an
explicit option meriting review within the context of current "cost achievability" requirements
of the CWA. The marginal costs of adding such a "step""to the review process would be
marginal compared to the total cost of standards development, perhaps on the order of
$300,000 to $500,000 per industry reviewed. The"aidditioiial" c'bs't"""isalmost entirely
attributable to the need to collect and analyze more "'detailed""data "on" in-plant production
processes and controls. If EPA were to consider pollution prevention techniques for all 19
industries, the total incremental cost would be in an estimated range of $5.7 to $9.5 million.
Jin i
Pollution prevention presumably would result in greater pollutant reductions than those
achieved by traditional treatment standards. Moreover, these techniques are also likely to
reduce pollutants more cost effectively, especially if multimedia impacts are considered (e.g.,
extensive use of pollution prevention techniques in the electroplating industry are being
driven by the high cost of disposing bf'RCRA'SubtidVC"\i^generated "as a
result of wastewater treatment). The magnitude of pollutant reductions possible from the use
of pollution prevention techniques is estimated at appirbxiinately 11 to 12 million pounds,
assuming that existing loads can be reduced from 10 to 90 percent in three industrial
categories (the Pharmaceuticals, electroplating/metal finishing, and machinery manufacturing
industries were selected to represent a range of pollution prevention potential among indirect
dischargers). Again, EPA is unable to express the monetary value of the benefits from
loadings reductions.
Requiring zero discharge of high risk persistent pollutants would reduce industrial user
contributions by roughly 4.5 million tons according to Toxic Release Inventory System
(TRIS). Persistent pollutants are discharged by essentially all industrial categories.
Requiring zero discharge of persistent pollutants from indirect discharges presumably would
also logically imply requiring zero discharge from direct discharges, since the nature of the
pollutant, and the impact on the environment are exactly the same. The costs of a blanket
prescriptive option are unknown, but are likely to be high and might involve a significant
number of plant closures and unemployment. Certain subcategories in the nonferrous metals,
iron and steel cold forming, and battery manufacturing industries have had "no discharge" as
' " ' 8-34
-------
a prescribed standard for certain pollutants in the past, but in these instances, such standards
were deemed economically achievable.
Pollutant-specific, nohdomestic pretreatment standards would represent a significant
departure from the current approach for categorical standards development with
environmental and administrative benefits of questionable value. Categorical standards are
based on what is technologically achievable within an industrial category or subcategory. The
concept of developing pollutant-specific standards is at odds with this approach. This option
would necessitate development of a water quality basis or other basis for uniform
concentration-based standard:;. Whereas the current effluent limitations concept fashions
controls to subcategories based on size, age, and other factors prescribed in the CWA, a
pollutant-specific approach would involve prescribing a "blanket" limitation irrespective of
available technology and cost. This is counter to the intent of the CWA.
In Chapter 6 of this report, pollutants were classified by a number of different criteria,
including persistence. Among the persistent pollutants found to be commonly discharged (as
measured by TRIS), 13 (CN, Ni, Cu, Ba, Mn, Pb, An, Cd, Ag, As, Zn, chloroform, 1,1,1-
trichloroethylene) have been detected in 26 separate industrial wastestreams. While
persistent pollutants do not represent a significant portion of pollutants discharged to
POTWs (less than 5 percent of the total volumes discharged to POTWs according to TRIS),
they are, nonetheless, important because of the ecological effects they can produce.
^ : . - •
The cost of developing a pollutant-specific limitation, while unknown at this point* would
likely be equivalent to conducting a major ecological study and a major categorical standard.
EPA's recently completed bioaccumulation study cost in the range of $500,000 to $750,000
and 5.5 workyears. The cost of developing an associated guideline is unknown.
Legal challenges could be expected, and resources would need to be expended to meet
these challenges, as well as subsequent remand/repair of the standards as necessary.
Establishing local limits for pollutants of concern may be a more cost-effective approach to
pollutant-specific control. As shown in Table 8-6, developing local limits is relatively
inexpensive (on the order of 200 professional hours exclusive of sampling and analysis) and
is currently targeted to the toxic metals (Le., the majority of those pollutants identified as
persistent).
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Not targeting persistent pollutants in pollutant-specific guidelines does not bar EPA
from paying special attention to them in the development or revision of traditional categorical
standards. In tliis way, the same result (additional control of5 persistent pollutants) could Be
achieved, without the expenditure of additional resources for ecological studies.
While reducing the loadings of pollutant from domestic sources has merit in site-specific
circumstances where domestic loadings represent a significant portion of total loadings,
national standards directed at controlling domestic sources are probably premature at this
time. A national approach would be necessary only if domestic sources precluded a large
number of POTWs from meeting environmental objectives. Moreover, establishing an
effective domestic source control program could be expensive, as well as extremely difficult to
i
implement and enforce. Permanent hazardous household waste collection programs are
facing costs of up to $2.50 per pound collected (or $.37- $1.10 per capita). While national
regulations may be premature at this time, EPA and the States can, and should, work with
local pretreatment programs to establish effective household hazardous waste programs.
Assuming 175 million persons are served by POTWs in the pretreatment program, EPA
estimates the total national cost of a domestic source control program to range from $40
million to $119 million annually. On the other hand, such programs may prove ineffective in
reducing toxic loadings to the POTW. High participation rates are difficult to encourage, and
more expensive programs will need to be adopted to create interest sufficient to reduce
loading significantly. In certain cases, where environmental benefits exceed the costs,
outright product bans under the Toxics Substances Control Act could be employed to control
discharges of certain toxic pollutants from households by prohibiting then1 manufacture or use.
A potentially significant source of specific pollutants from domestic sources (e.g., lead,
copper, zinc, manganese) soon may be reduced because of EPA's August 1988 proposed
rulemaking (40 PR 31516) undertaken by EPA to reduce the concentrations of lead in drinking
water. As a result of this rulemaking, it is projected that at least 39,800 public drinking water
systems will be installing corrosion control, and another 8,300 systems will require lead pipe
replacement. For systems serving more than 50,000 persons (the group of systems most
likely to be co-located with prepreatment POTWs), it is projected that nearly 500 will be
installing corrosion control and that about 230 will require lead pipe replacement. While
primarily intended to reduce lead levels in drinking water systems, these actions should
lower concentrations of the aforementioned metals in domestic sewage and in releases to
environmental media.
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8.3.2 Evaluation of Alternative 2: Improve/Restrict Site-Specific Standards
Four separate options were presented coincident with this alternative. The first two
options concerned removal credits: Option 2.1 provided for regulations to restrict removal
credits to biodegradable pollutants; Option 2.2 provided for the regulations to require more
rigorous testing. The next two options concerned local limits: Option 2.3 provided that the
current guidance with improvements be promulgated as regulations; Option 2.4 provided that
the basis for local limits be expanded to include all media endpoints. Removal credits and
local limits are provided to fine tune national standards to meet local, site-specific objectives
to protect the plant, sludge quality, water quality, and worker health and safety as well as to
prevent redundant treatment. Therefore, both require the POTW authority to be well aware
of the effect of toxic pollutants on the ambient environment (see alternative 3: enhance
. environmental controls on POTWs).
Granting removal credits for transfer, rather than treatment, of pollutants is counter-
productive to the intent of EPA's pollution prevention program. A simple evaluation of
influent and effluent concentrations of specified pollutants is highly unlikely to represent the
" removal efficiency for any single pollutant, given the variability in removal efficiencies.
Optimally, the sampling regime should be lengthened, with a sufficient number of discrete •
samples being taken to better accqunt for hydraulic retention times. Thus, removal credit
demonstrations should provide much more extensive data than they have in the past, perhaps
achieving the 95 percent level of confidence associated with BAT guidelines for direct
dischargers. ,
Requiring sufficiently detailed removal credit demonstrations will involve substantial
costs to POTWs. If influent/effluent sampling were required for a complete month, then
sampling and analysis costs would increase at least 2.5 times from current costs (12.
sampling and analytic events versus 30 events) if credits were restricted to biodegradable
pollutants. More extensive testing requirements, such as headworks, aeration basin, and
sludge monitoring, may be necessary if removal credits were to be made available for other
than biodegradable pollutants and it were decided that removal credits would be available
only to the extent of actual treatment in the POTW (rather than transfer to other media).
Removal credit demonstrations also impose a cost for State/EPA officials. Review of
removal credit demonstrations can consume workweeks, rather than workdays. Technically,
removal demonstrations are similar to local limits and fundamentally different factor variance
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reviews, which generally consume up to 150 professional hours ($7,500) over a period of a
few weeks.
Finally, the actual number of applicants interested in taking advantage of removal
credits may not warrant providing for such relief. Thirteen separate control authorities were
granted removal credits prior to the 1987 suspension; another 14 applications from control
authorities were pending. Together, approximately 150 indus'bial users"Beriefited'by"tIie~
approval of the removal credits. Discussions with me Assbciatibh of Municipal Sewerage
Authorities regarding this report suggest that POTW interest in seeking removal credits has
waned since the early years of the pretreatment program. Should the cost of preparing
removal credit applications be increased (beyond the current estimated cost of removal credit
preparation of $11,000; approximately half the cost is associated with sampling, the other half
with application preparation), or the number of pollutants for which credits are available be
decreased, further interest in receiving removal credits would be discouraged.
Options 2.3 and 2.4 provide for an enhancement of local limits. Option 2.3 would call for
the establishment of mandatory local limits procedures, based on the codification of the
essential elements of Guidance'Manual on the D'evelppment and Implementation of Local
Discharge Limitations Under the Pretreatment Program (EPAj 1987) Option 2.4 would
mandate the application of local limits to protect all media endpoints. These two options
complement one another.
The local limits program has had its successes, especially since the development of the
guidance and attendant training sessions. As described elsewhere in this study, a growing
number of pretreatment POTWs have developed environmentally protective, defensible local
limits in the last few years. Clearly, guidance can be an effective mechanism for program
improvement, especially when accompanied by an intensive training and oversight effort. In
addition, POTWs are generally developing limits for more pollutants than appear in their
NPDES permits'." It is reasonable to assume that if more toxic limits appeared in the
POTW's NPDES permit, the POTW would, in turn, develop additional local limits.
Local limits developed in accordance with EPA's guidance (i.e., technically based) can
be developed by a POTW for 200 workhours, exclusive of sampling and analysis costs.
Development costs may increase as a result of the number of pollutants regulated, criteria
under consideration, and permitted industrial users! Ttius,' sfioufd me number of mectia"
endpoints considered be increased, the cost would remain reasonable, perhaps running to 250
, , ,8-38 • ' ,
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or 300 hours. The tools to develop local limits are available, and they offer a cost-effective
approach toward achieving environmental objectives.
Codifying the guidance could result in expenditures for local limits development up to
$15.6 to $23.4 million, assuming that 33 percent of POTWs have already developed local
limits based on the guidance. However, these costs do not represent an accurate estimate of
true incremental increase in the preparation of local limits, in that POTWs are already
required to develop adequate limits. This option merely clarifies the requirement, and
pretreatment POTWs are already incurring many of the costs that this option would entail.
Expanding the number of media endpoints would not likely increase total estimated costs by
more than 25 percent (or about 50 hours) per POTW, including those that already have
developed local limits. Thus, up to $6 million in labor costs may be incurred.
The cost of reviewing local limits varies in accordance with the complexity of the
submission. Average review costs run from 50 to 80 professional hours, or from $2,500 to
$4,000 per review. On a national basis, this amount works out to approximately $6 to $9
million. The cost of reviewing local limits incorporating all media endpoints would most likely
fall within this cost estimate range. However, these reviews will be conducted whether or
not the guidance is codified; any change would be in the local limits themselves, not the
review costs.
8.3.3 Evaluation of Alternative 3: Enhance Environmental Controls at POTWs
The three options involve EPA issuance of environmental criteria, inclusion of toxic
limits in POTW permits for all wastestreams, and corrective action requirements for cleanups
of past releases from POTWs.
The first and second options are the linchpins of the National Pretreatment Program.
The development and application of environmental criteria will encourage POTWs to develop
local limits and to-initiate pollution prevention and other initiatives for their industrial,
commercial, and domestic users. Development of water quality criteria is underway at EPA,
and development of sediment quality criteria is at the preliminary stage. Criteria
development will only spur limits development to the extent States adopt water quality
standards (or EPA promulgates standards for the States) and POTW permit limits are
developed to meet those standards. For example, despite the existence of national aquatic
life and/or human health criteria and guidance for the priority pollutants, most pretreatment
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POTWs do not have limits for those pollutants in their NPDES permits: 32 percent had toxic
metal limits; 11percent had toxic organic limits.
EPA's municipal sludge regulations were proposed on February 6, 1989 (54 FR 5746),
and are now scheduled for promulgation in early 1992. In the meantime, EPA has mounted an
interim permitting strategy that establishes standard conditions and baseline monitoring
requirements and, where problems are known or suspected, requires best management
practices to abate problems. At this time, the sludge permitting procedure is not expected to
increase POTW or permitting authority costs by more than a workday per permit.
In addition, 171 pretreatment POTWs appear on the Agency's 304(1) list and are prime
candidates for permit revisions incorporating toxic limits. Workload estimates indicate that
each permit should cost the permitting authority from $10,000 to $15,000 (exclusive of model
, ^ ,
'development and wasteload allocation costs and sludge permitting requirements).
Expressed in staffing needs, the total workload in writing water quality-based permits for all
pretreatment POTWs is 60 workyears (again exclusive of wasteload allocation costs and
sludge permitting requirements).
The variability in wasteload allocation costs is a prime factor of concern in developing
toxic limits for permittees. In a simple case, a permit writer may use a dilution calculation. In
other cases, more sophisticated modeling for a single discharge situation may involve a 6- to
22-week effort. In a still more complex situation, involving multiple dischargers, the
wasteload allocation process may involve anywhere from 15 workweeks to 5 full workyears.
In most situations, a simple dilution analysis is sufficient, but the more complex situations
can realize a significant resource drain. Assuming all POTWs should receive water quality-
based permits and each wasteload allocation involved a 6-workweek effort, the total
wasteload allocation cost would total approximately 250 workyears.
Requiring cleanup, termed corrective action by the RCRA program and remedial action
by the Comprehensive Environmental Response, Compensation, and Liability Act program, at
POTWs would involve remediating past releases posing risks to human health and the
environment. This cleanup program could be conducted by POTWs in much the same way the
process works for the RCRA program (i.e., a cursory review of operations and releases
followed, as necessary, by a more comprehensive assessment of those releases, a study plan
for remediating those releases, and remediation). A minority of POTWs, those subject to
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RCRA permits-by-rule as a condition of receiving hazardous wastes by truck, rail, or
dedicated pipeline, are currently subject to this cleanup process.
The first phase of the process, the cursory review of facility operations and potential
releases, will cost the permitting authority an estimated $8,000 to $12,000 to conduct (or 4 to
6 workweeks). If all pretreatment POTWs were to receive such assessments, this could
absorb on the order of 200 workyears (about two-thirds of the cost associated with
developing water quality-based permits). The actual costs of cleanup cannot be estimated at
this time. Currently, insufficient information exists on the nature, extent, and significance of
contamination that may be associated with releases from POTWs to warrant
recommendation of this option. If subsequent environmental data suggest widespread
problems at POTWs, a corrective action model may be appropriate.
8.3.4 Evaluation of Alternative 4: Expand Pretreatment Monitoring Requirements
This alternative encompasses three separate options involving the expansion of SIU
monitoring requirements, POTW wastestream monitoring requirements, and POTW ambient
monitoring requirements. Monitoring for more and better data has two principal objectives:
(1) it serves as a basis for further action, and (2) it provides feedback on program progress.
In addition, the expansion of monitoring requirements would likely increase compliance by
increasing SIU fear of being subject to enforcement actions. All options would involve
significant expenditures (from tens to hundreds of millions of dollars) of resources and,
therefore, all merit serious scrutiny prior to adoption—including an analysis of whether the
environmental benefits to be gained exceed the costs.
A regulatory modification requiring semiannual testing of 30,000 SIU effluents can be an
expensive exercise. Three tests (effluent monitoring, toxicity testing, prohibited discharge
monitoring) are prescribed to be conducted four times per year, as indicated in Table 8-6.
Together, these three tests could result in annual expenditures of between $35.3 and $227
million; Yet, additional monitoring only indirectly results in achieving the goals of the CWA.
Conducting priority pollutant scans can cost more than $1,000 per event. A more flexible
monitoring approach tailored to the industrial user, increasing the frequency of metals
monitoring for some industries and decreasing it for others, may offer more tangible benefits
for dollars expended.
The preliminary data summaries prepared by EPA's Office of Water, TRIS data base,
and site-specific inspections (e.g., compliance history, pass through,, and interference events)
. '",''•' : ' 8-41 .'.'*,
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all provide basic information that POTWs can use in establishing monitoring requirements
(frequency and pollutant coverage) for industrial users.
Under Option 4.2, POTWs would be required to conduct more indepth monitoring
(monthly influent/effluent tests, monthly sludge analyses, quarterly effluent toxicity tests) of
their wastestreams. The prime objective in requiring increased wastestreafn mbnitbring is
the effect such action would have on spurring local limits development and assessing
compliance with water quality-based permits. This option is compatible with option 3.2,
which calls for mandatory toxic limits in pretreatment POTW permits.
The total estimated annual cost of the POTW wastestream monitoring option is
estimated within a range of $63 to $124 million, depending on how many pollutants will be
analyzed ($200 for a metals analysis versus $1,100 for a priority pollutant scan) per sample
and the type of toxicity test ($200 for an acute test, one species versus $1,200 for a battery of
chronic tests) selected. The projected cost estimate ranges for this option are similar to the
SKI monitoring option ($35.3 to $227 million for lUs versus $65 to $135 million for POTWs),
but the benefits to the POTW and receiving environments are more tangible. In addition, this
||, ' I, , „„ fllll,, „ |'" ' , , '„. • • 'I, '"' ,,,1,,' , ,,'i|, !' i1 i"1'',,„?'.,IliJ'i'r,»!!,]':. I1: IN II1, "I" ,,i Ili .'i I"1 , IWyl. !!,ii.ii!lll i, ill liil * i i ''I','"',!'.''i1'!!!!,,:,1 VITW;:^!'!! ":«!,:•,!, '".Sli!1!!" i
option may underestimate the number of POTWs currently monitoring their wastestreams
(and thus overestimate the costs), since many POTWs monitor without reporting results to
EPA. ' . ' .
The third option provides that POTWs monitor the ambient environment (water,
sediment, ground water, air) as a standard permit condition. Chapter 6 demonstrated that
POTW releases can have a deleterious effect on each media endpoint. However, in large
part, the data were determined inadequate for a complete national assessment of the effect
that toxic discharges from POTWs have on the ambient environment. Generating ambient
data can be expensive. As shown in Table 8-6,. surface water sampling (biological) could
involve an annual cost range of $19.5 to $39 million. "Air quality monitoring of the headwords
and aeration system involve costs in the range of 3 to 4 times ($76 to $130 million) that of
surface water sampling. The cost of ground-water sampling is similarly expensive, especially
if ground-water monitoring systems will need to be designed and installed.
'While the analyses completed in support of Chapter 6 were not sufficient to develop a
complete national assessment, that chapter does conclude that toxic discharges from POTWs
are clearly affecting the aquatic environment. Therefore, should POTWs be required to
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monitor any single medium, that medium should be water. Biological monitoring is an
effective means of assessing both water and sediment quality.
The biological monitoring costs provided in Table 8-6 are based on Ohio EPA
experience. They assume that an average reference site survey, incorporating fish and
macroinvertebrate sampling, costs a total of .03 workyears (62 workhours or $3,100 at $50
per hour).
8.3.5 Evaluation of Alternative 5: Shift Administrative Burdens/Responsibilities in the
National Pretreatment Program
Chapter 7 concludes that pretreatment program deficiencies in applying categorical
standards, issuing permits, and conducting compliance monitoring can be attributed to
technical errors and shortcomings that were relatively common early in the program's history.
Five States have chosen to administer a statewide program rather than delegate
responsibilities to the local level. There is no indication that these programs have
experienced a lesser or greater degree of deficiencies as a result of their administrative
structure. .
- ' /
Chapter 7 also concludes that the pretreatment program's fundamental strength is the
flexibility that implementation at the local level provides. Indeed, one could argue that
whereas the POTW is dedicated to water quality protection and has an established financial
structure to fund its activities, State and Federal water quality programs continually compete
for resources with other environmental programs. Thus, the POTW authority may be in a
more stable financial condition and can offer a more stable organization for day-to-day
management of the pretreatment program.
The technical errors that have occurred can be remedied by additional training and
guidance. Indeed, recent training efforts, such as those directed at developing local limits,
have been well received and have had tangible results.
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REFERENCES
' ' ! J ' t ,i '," ' I",' " \-:: HI-
,, , '!,„
U.S. Environmental Protection Agency. 1987. Guidance Manual on the Development and
Implementation of Local Discharge Limitations Under the Pretreatment Program.
Washington, DC: Office of Water Enforcement and Permits.
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9. FINDINGS AND RECOMMENDATIONS
In the preceding chapters, the U.S. Environmental Protection Agency (EPA) presented
specific findings pertaining to:
• The sources and amounts of toxic pollutants discharged to publicly owned treatment
works (POTWs)
• The extent to which toxic pollutants are removed by secondary treatment plants
• The capability of POTWs to modify national pretreatment standards by developing
removal credits and local limits
• The adequacy of data on environmental impacts associated with toxic discharges from
POTWs
• The effectiveness of the existing pretreatment program in programmatic and
environmental terms . .
• Evaluation of regulatory alternatives.
Section 9.1 summarizes the findings of this Report to Congress. Recommendations
stemming from these findings are discussed in Section 9.2.
9.1 FINDINGS
Major findings from this Report to Congress are presented below. Each finding is
derived either from specific analyses conducted for this report or from other recent program
reports or data. The findings are organized according to the six substantive chapters of the
Report to Congress.
9.1.1 Sources and Amounts of Pollutants Discharged to POTWs
• Sources
- Nationwide, over 15,000 POTWs receive and treat a total of approximately 34
billion gallons per day of domestic, commercial, and industrial wastewater.
- A total of 1,542 POTWs (encompassing 2,128 individual municipal wastewater
treatment plants) are required to have approved local pretreatment programs. As
of March 1990, 1,442 of the 1,542 (94 percent) have approved local programs.
Toxic discharges to another 314 POTWs are regulated by State-run pretreatment
programs, pursuant to 40 CFR 403.10(e), in lieu of local programs. Those POTWs
with approved pretreatment programs and those covered by State-run programs
receive more than 80 percent of the national wastewater flow discharged to
POTWs.
- EPA estimates that 30,000 significant industrial users (SIUs) discharge .to
POTWs. This number comprises approximately 11,600 categorical industrial users
and 18,400 noncategorical SIUs.
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— Several hundred thousand other nondomestic users discharge to wastewater
treatment plants across the United States. These facilities include retail and
commercial establishments, as well as industries deemed[nonsignificant.
Sources and Types of Industrial Discharges
- The Domestic Sewage Study•l^SS)rassumm'g"impositibii of and compliance with
categorical Pretreatment Standards for Existing Sources (PSES), identified the
following industrial categories responsible for the highest loadings of 165 metals
and toxic organics to POTWs:
Metals: Electroplating and metal finishing; industrial and commercial laundries;
organic chemicals manufacturing; coal, oil, petroleum products and refining; and
pulp and paper mills.
Organics: Equipment manufacture and assembly; pharmaceutical manufacture;
organic chemicals manufacturing; coal, oil, petroleum products and refining; and
industrial and commercial laundries.
- Data from the Toxic Release Inventory System (TRIS) regarding releases of more
than 300 listed toxic chemicals showed that more than 5,700 industries estimated
discharges of more than 680 million pounds of toxic pollutants to more than 1,700
POTWs in 1988. The industrial categories reporting the largest volume released
to POTWs were fertilizer manufacturing, organic chemical manufacturing, dye
manufacturing and formulating, pulp and paper mills, food and food by-products
processing, and pharmaceutical manufacturing.
— For the 165 pollutants analyzed in the DSS (plus copper and zinc), annual POTW
loadings of toxic pollutants reported in TRIS (159 million pounds) exceed loadings
estimated in the DSS (60 million pounds), although the DSS represented more
facilities discharging to POTWs.
Other Potentially Significant Sources
- Findings for the DSS, TRIS, and EPA's 304(m) plan suggest that commercial and
industrial facilities not yet subject to categorical pretreatment standards may
discharge significant quantities of toxic pollutants to POTWs. These include
machinery manufacturing arid rebuilding, industrial and commercial laundries,
hazardous waste treatment facilities, and waste reclaimers.
— Domestic wastewaters may contain considerable amounts of toxic pollutants as a
result of the disposal of household hazardous wastes'. In some cases, pollutants
contributed by drinking water supplies and drinking water conveyance systems
may also be significant. Inorganic pollutants present in domestic wastewater
include metals, such as copper, iron, lead, and zinc. Organic compounds may
include pesticides, plasticizers, coal tar compounds, and chlorinated solvents.
— While concentrations and loadings of toxic pollutants from domestic sources are
typically lower than those from commercial and industrial sources, domestic
loadings at specific POTWs may be significant enough to contribute to pass
through and interference. Thus, some POTWs have undertaken to reduce
domestic contributions through adjustments to treatment of drinking water
supplies and through product restrictions, as well as by hazardous household
waste collection programs.
9-2
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- POTWs may also receive significant loadings of toxic pollutants from hauled
wastes, landfill leachate, storm water, or cleanup activities associated with RCRA
corrective actions, Superfund cleanups, and underground storage tanks.
• Types of Controls
- Categorical standards and local limits have brought about significant reductions in
metals loadings and moderate reductions in toxic organics loadings from regulated
industries.
Metals: Toxic metals pollutant loadings from regulated industries are estimated to
be reduced by 95 percent after implementation of PSES. This reduction results in
estimated annual loadings of about 14 million pounds (6,500 metric tons).
Organics: Depending on the data source, toxic organic loadings from regulated
industries are estimated to be reduced by approximately 40 to 75 percent after
PSES, resulting in annual loadings of approximately 65 million pounds (30,000
metric tons). .
— Planned development of additional categorical standards for such industries as
machinery manufacturing and rebuilding, pharmaceutical manufacturing, industrial
laundries, paint formulating, and hazardous waste treatment is expected to further
reduce loadings of toxic pollutants to POTWs.
- POTWs and industrial users have demonstrated that they understand pollution
prevention and the opportunities it affords to reduce loadings of toxic pollutants.
EPA has found that pollution prevention techniques have been used at 36 of the 47
industrial categories evaluated in this report.
- In 1989, over 600 household hazardous waste collection programs were in place,
many of which were coordinated by POTWs. Further reductions in toxic pollutant
loadings from nontraditional sources of pollutants, including commercial and
domestic sources, may be necessary to obtain the reductions needed to achieve
desired environmental standards.
9.1.2 Extent of Removal of Toxic Pollutants at Secondary Treatment Plants
• Fate of Toxic Pollutants
- Toxic pollutants present in the raw sewage entering secondary treatment plants
have several fates. Toxic organic pollutants can biodegrade, partition to sewage
sludge, volatilize, or remain in the discharge to receiving waters. Metals generally
partition to the sewage sludge or remain in the discharge from the POTW.
- The removal of most toxic pollutants from wastewaters is largely incidental to the
treatment of conventional pollutants and should be considered in terms of
partitioning among alternative pathways; pollutants may be shifted from one
medium to another (to the air through volatilization or sludge through adsorption),
as well as destroyed through biodegradation.
• Nature of Pollutant Removals
- Pollutant removal is calculated from the results of sampling the influent and
effluent of a POTW treatment plant.
- Calculation of removals of toxic pollutants at a POTW must consider that removal
of toxics involves several pathways and is variable because of changing conditions
9-3
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and situations at the POTW (e.g., concentration of the pollutant, POTW
operational characteristics, aeration/turbulence, temperature).
— EPA's analyses of priority pollutant removals indicate that "removal of efficiencies
vary widely from POTW to POTW.
- Removal efficiencies do not appropriately represent POTW variability when
expressed as single median values because of variability of observed removals.
- The broad range of removal efficiencies observed underscores the need for using
POTW-specific data in making decisions that involve toxic pollutant removals
applicable to individual POTWs.
9.1.3 POTW Capability to Revise Pretreatment "Standards ".
• Status of Removal Credits
— Removal credits are adjustments to categorical pretreatment standards that reflect
the removal of a pollutant by a POTW. A POTW may elect to lessen the
stringency of a categorical standard where it demonstrates it consistently removes
a given pollutant, and maintains compliance with its National Pollutant Discharge
Elimination System (NPDES) permit and sludge requirements. The removal
credits program has been suspended since 1986. Removal credits will remain
unavailable until EPA promulgates sludge requirements pursuant to Section 405 of
1 the Clean Water Act (CWA).
- When the removal credit program was suspended in 1986, 12 POTWs nationwide
had removal credits approved by EPA, and another 15 had removal credit
applications pending. The approved removal credits covered 16 pollutants and
affected approximately 150 industrial dischargers.
- Future POTW interest in removal credits, once they are available again, is
expected to be low; however, increased regulation of organic pollutants in recently
promulgated arid forthcoming guidelines may renew interest in removal credits for
some organic compounds.
• Assessment of POTW Capability: Removal Credits
- POTWs generally possess adequate resources arid technical expertise to perform
the tasks inherent in revising pretreatment standards through removal credits
(e.g., monitoring and calculation of revised standards).
- Most of the pollutants for which removal credits were granted (or for which they
have been applied) are metals that do riot biodegrade in municipal treatment
systems and that are partitioned instead to sludge.
- While both best available technology economically achievable (BAT) (direct
discharge) and PSES (indirect discharge) standards are set such that the
applicable technology can meet the limit 99 percent of the time for daily maximum
and monthly average limitations, a POTW's demonstration of "consistent"
removal for purposes of removal credits does not require the same degree of
confidence. Since a POTW pursuing removal credits for its industrial users need
only show that it can achieve removal 75 percent of the time, its treatment
combined with its industrial users' treatment may be less than that provided by
direct dischargers. Additionally, the regulations do not require that POTWs with
combined sewers provide treatment consistent with direct dischargers.
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Status of Local Limits
- Analysis of local limits at 200 POTWs found that 90 percent of POTWs have
adopted local limits for one or more toxic pollutants and over 70 percent have
adopted local limits for the 10 pollutants listed in EPA guidance as being of highest
concern. A much smaller percentage, however, has adopted local limits using a
headworks loading or other technical basis. POTWs surveyed by the General
Accounting Office were found to impose local limits for an average of 14 toxic
pollutants.
- The most prevalent limits were for copper, cadmium, lead, nickel, zinc, chromium,
cyanide, mercury, arsenic, and silver. Only one toxic organic, phenol, was found in
the top 20 pollutants regulated in local limits. This organic is controlled by local
limits at 49.5 percent of the 200 pretreatment POTWs reviewed.
- POTWs regulate for many more pollutants in their local limits than they are limited
for, in their NPDES permits. According to EPA's Permit Compliance System
(PCS), only 32 percent of the NPDES permits for pretreatment POTWs issued in
1989 contained any limits for one or more toxic pollutants.
Assessment of POTW Capability: Local Limits .
- POTWs are generally capable of developing and implementing local limits.
Weaknesses observed include the following:
- -' In developing local limits, POTWs generally lack site-specific data necessary
to calculate treatment plant removals. The current practice of using literature
POTW removal data to develop local limits may not accurately reflect
treatment plant performance and may result in exceedances of environmental or
technical criteria.
- - POTWs often rely on literature data to predict pollutant concentrations that
may result in unit process inhibition. These literature inhibition data are based
on a limited sample size and may not accurately characterize site-specific
conditions. Additionally, these data are available for only a few pollutants and
treatment processes.
-- The application of local limits to categorical industries often involves
comparisons with the categorical standards to determine which of the limits
(local or categorical) are more stringent. Although EPA has provided guidance
to address this issue, POTWs continue to have difficulty applying the most
stringent standard.
- POTWs often lack sufficient environmental standards, criteria, or permit conditions
to judge the appropriateness of local limits. NPDES permits for two-thirds of the
POTWs with pretreatment programs do not contain limits for any toxic pollutants.
Of those that do, only a few pollutants are generally limited. In addition, national
sludge disposal standards are not yet in place, and most States do not have
comprehensive sludge standards. POTWs, therefore, are often without specific
environmental criteria and standards upon which limits are to be based.
9-5
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9.1.4 Adequacy of Data on the Environmental Effects of Toxic Discharges From POTWs.
• Types of Effects and Pathways
— Discharges of toxic pollutants from POTWs can impair the quality of receiving
environments, including surface water, ground wafer, and air. In addition, the
health anci safety of workers at POTWs may be ^v^^iy affected.
— In general, metals pass through treatment plants to surface waters or are
partitioned to sludge in roughly equal proportions. Toxic organics that are not
biodegraded either volatilize to air,or are released to surface waters, with few
adsorbing to sludge.
— Toxip effects vary by pollutant, as well as by receiving medium. Principal effects of
concern are lethality, carcinogenicity (causing cancer), teratogenicity (causing
developmental abnormalities), or mutagenicity (causing genetic abnormalities).
Some compounds discharged from poTWs (P'CBs and arsenic) exhibit all of these
deleterious effects. Several metals are lethal, teratogenic, and mutagenic but do
not cause cancer.
• Extent of Environmental Criteria
— The lack of comprehensive criteria for all ^e'p"olfulia^s'''cCiscliargeci to and from
POTWs inhibits estimation of the environmental effects of POTW discharges.
— In addition, the POTWs, States, and EPA do not collect or maintain data that are
comprehensive enough to adequately characterize municipal wastestreams or their
impacts in receiving environments. Data on POTWs are most comprehensive for
discharges to surface water. .
• Surface-Water Impacts
— Eighty percent of POTWs covered by pretreatment programs discharge treated
effluent to rivers and streams, 4 percent to lakes, 7 percent to oceans, and 9
percent to other environments, including land, estuaries, and reservoirs.
- Under the 304(1) program, 254 POTWs (171 pretreatment POTWs) .are among the-
888 facilities contributing toxic pollutants to stream segments not attaining water
quality standards. . .
— Of the water bodies States assessed in 1988, States reported that 21 percent of
river miles, 21 percent of lake acres, and 19 percent of estuary areas were reported
to not be fully meeting use designations as a result of toxic pollutant discharges
from all sources.
— Municipal sources (including both pretreatment and nonpretreatment cities) are
reported as second in importance (behind Agriculture) in causing use
nonattainment. ^ '
— Limited toxics monitoring data, including ambient stream data for pretreatment
POTWs, indicate a high probability that pretreatment POTW discharges of toxic
pollutants are affecting receiving waters. For example, nearly 53 percent report
concentrations that would exceed chronic water quality criteria; 20 percent of the
discharges of copper, cyanide, cadmium^ PCB"s7silverjTan"d lead"cause exceedances
of chronic criteria. While these projected exceedances do not necessarily lead to
actual toxic effects at a particular POTW and receiving stream, they suggest that
concentrations are sufficiently high to warrant toxic limits in NPDES permits.
9-6
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- Toxicity testing results from one EPA Region indicate that 17 percent of the acute
tests exceeded EPA's Criterion Maximum Concentration. Chronic test
exceedances were even higher.
• Ground-Water Impacts
- The most significant potential cause of ground-water contamination by POTWs is
disposal of sewage sludge, although empirically this has rarely been a problem.
Forty-two percent of all municipal sewage sludge is beneficially used in land
application, 22 percent is disposed of in landfills, 14 percent by incineration, 6
percent through distribution and marketing, 5 percent by ocean disposal, and 2
percent by other practices. Roughly three-quarters of sludge is used or disposed
of in land-based practices.
- In the Lagoon Study, EPA found that there is a low potential for ground-water
contamination from municipal wastewater lagoons, but that lagoons with industrial
discharges may be potential sources of ground-water contamination.
- Pollutants under consideration for regulation in EPA's proposed Sludge Technical
Criteria were detected at high frequency in the National Sewage Sludge Survey
(NSSS). Of the 34 pollutants for which limits have been proposed, 11 were
detected more than 50 percent of the time.
- Pollutants under consideration for regulation in EPA's proposed Part 503
regulations for sludge use and disposal were detected at high frequency in the
NSSS. Mean concentrations of certain toxic metals (arsenic, cadmium, copper,
lead, molybdenum, nickel, and zinc) found in sludge in the NSSS suggest that
some POTWs may be precluded from certain beneficial use or disposal practices
unless they can reduce loadings through additional pretreatment.
• Air/Worker Health and Safety Impacts
- Little is known about the extent and effects of air emissions from POTWs. The
DSS estimated that 0.1 percent of the mass of national emissions of volatile
organic compounds may come from POTWs. Twenty-seven POTWs nationally
are reported to emit over 100 tons per year of Clean Air Act criteria pollutants.
- Of the 2,414 disabling injuries reported at wastewater treatment plants, a small
percentage may be caused by discharges to POTWs: 2.4 percent involved
respiratory injuries, 5.1 percent irritation from exposure to chemicals, and 1.6
percent chemical burns, all effects that may be attributed to industrial wastes.
9.1.5 Effectiveness of the National Pretreatment Program
• Program Scope
- The pretreatment program has targeted the appropriate POTWs for control of
nondomestic sources. Of more than 15,000 POTWs in the Nation, pretreatment
program requirements are being implemented by 1,442 local control authorities at
2,015 treatment plants and by five States at 314 plants. Another 100 local
programs, covering 113 plants, are being developed. These pretreatment programs
and their POTWs are collectively responsible for more than 82 percent of the
Nation's municipal wastewater treatment capacity, and they receive the vast
majority of all industrial discharges to POTWs in the United States.
- Virtually all the POTWs reported in TRIS to be receiving over 1 million pounds of
toxic chemicals are covered by programs. Evaluation of various data sources (e.g.,
• '9-7 '
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TRIS,NEEDS, 304(1) data) may enable EPA to target additional POTWs for
development of local pretreatment programs.
— Categorical and other industrial users discharge more toxic pollutants, particularly
toxic organics, than are regulated by either categorical standards or local limits.
• Implementation Status
— Measurements of the level of programmatic implementation of local programs
indicate that local implementation is well underway. Ninety-four percent (totaling
1,442) of required local pretreatment programs have been approved. Twenty-
sevenStates have approved State ^^.QQ^^ programs^Specific programmatic
implementation issues will require more attention, such as the need for POTWs to
develop technically based local limits and to adequately enforce all pretreatment
Standards and requirements.
— PCS indicates that 84 percent of SIUs have been issued control mechanisms, and
90 percent of SIUs have been inspected under local programs.
— Estimates of industrial noncompliance range from 10 percent (PCS), to 17 percent
(International Joint Commission), to 41 percent (General Accounting Office). This
is higher than the corresponding SNC rate for direct dischargers.
— EPA Regions and States have performed extensive oversight of local pretreatment
programs, having performed more than 3,600 audits and inspections at 1,328
POTWs,"in the last 5 years. ' • ' ;
— To assist POTWs and States in implementing the pretreatment program, EPA has
released 37 guidance manuals and conducts 46 workshops and seminars per year.
— One of the pretreatment program's key strengths is implementation at the local
level, which provides the flexibility necessary to respond to site-specific
conditions. In general, locally implemented programs have been found to regulate
more npncategorical industries than State-run programs. In contrast to State-run
programs, local programs have developed and implemented site-specific' local
limits to prevent pass through and interference and have conducted more frequent
monitoring of industries to assess compliance.
— The decentralized local approach has, however, resulted in instances of incomplete
or inconsistent implementation of local pretreatment programs. As many as 40
percent 6f the approved local pretreatmeht program's need'td improve at least one
key area of implementation (e.g., issuance of industrial user control mechanisms,
development of local limits, enforcement).
* Environmental Results
The lack of comprehensive environmental data makes it difficult to evaluate the
program's effectiveness in achieving the goals of the CWA. However, evidence
from various data sources suggests that the pretreatment program has resulted in
significant reductions in Ae" discharge' of toxic p'bllutants to pQTWs arid from
POTWs to the environment.
, • jMi:' • -in1 , • ..• : :; „« ;", 'i:. ,«., ':,i;lii":-: '.^V'IL I'.iu"1^ i".:.1;".; •'>:si liupBiHi..'^, i,1 iSiiiiiiK^ nifrvJiiiiyf i;,I'iir wi: is *;," "!A 'vti, .''iii'sssi
Many POTWs report significant declines in concentrations and loadings of toxic
pollutants in influent, effluent, and sludge associated with implementation of
pretreatment programs. These decreases have reduced operational problems and
have improved the quality of receiving waters and sludges.
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9.1.6 Alternative Regulatory Strategies for Pretreatment
• The overall regulatory framework for control of toxic discharges to POTWs appears to
provide suitable mechanisms to address environmental concerns.
• EPA considered five alternative strategies that might be appropriate:
(1) enhancement of national pretreatment categorical standards, (2) improvement of
site-specific standards and modifications, (3) better environmental controls on
POTWs, (4) improved monitoring, and (5) a shift of administrative responsibilities.
• Regulatory improvements were found desirable in three of the five areas: enhancing
pretreatment standards, improving site-specific standards, and enhancing
environmental controls on POTWs. Section 9.2 provides more detail concerning
these improvements.
• The benefits to be derived for each action have not been quantified in monetary terms.
9.2 RECOMMENDATIONS
From the major findings in this Report to Congress, EPA recommends the following
approaches, none of which will require statutory changes, to further reduce the environmental
impacts associated with toxic discharges to and from POTWs:
• Continue to promulgate national categorical pretreatment standards and stress the
adoption of cost-effective pollution prevention and domestic wastewater controls
wherever feasible.
• Improve local pretreatment standards (both removal credits and local limits) to
further reduce toxic loadings and to ensure the integrity of POTW collection systems.
• Improve the scientific basis of pretreatment controls, and provide better benchmarks
for pretreatment program performance, by establishing comprehensive standards and
criteria for all media affected by POTW discharges.
Aspects of these broad recommendations are more fully explained below. It should be
.noted that EPA is currently undertaking many regulatory development and program
implementation activities envisioned by these recommendations. These recommendations do
not comprise entirely new initiatives, but are intended to complement ongoing water pollution
control efforts by municipalities, States, and the EPA.
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Recommendation One: Enhance National Categorical Pretreatment Standards
• Continue to develop new and revised categorical standards in accordance with EPA's
plan developed under 304(m), and continue to review new pollutants, particularly
those nonpriority pollutants now known to pose significant environmental risks, for
inclusion in categorical standards. Where final standards are not necessary on a
national basis, issue guidance to POTWs on problem pollutants and control options.
1 • „,. •„„ si1* !: j'.' ',,,,, , „' '.."'"..ii'i;,,! i,,''i ii IP i n i in INI 1 inn 111111 ii nil 11 in in iiiiiiinnni 11 n IP n ii nun ni n iii i inn J n iini in i
• Continue to consider cost-effective pollution prevention techniques as the basis for
categorical standards where such techniques offer the best available technology
economically achievable (BAT). '.
• Reexamine the removal credit requirements of the General Pretreatment Regulations
(§403.7) in light of the findings of this report. Further topics for examination might
include the definition of consistent removal, monitoring requirements, types of
compounds for which removal credits are and are not available, the use of data from
similar POTWs, and specific conditions for inclusion in the NPDES permit once
removal credits are approved.
Recommendation Two: Improve Local Pretreatment Standards
* Promote opportunities for use of cost-effective pollution prevention tools in industrial
user permitting, local limits development, spill control, and inspections to reduce
nondomestic loadings of toxic pollutants. Encourage market forces and industrial
user input into the process of developing and allocating POTW local limits.
• Promote domestic hazardous waste programs and other opportunities to reduce
discharges of pollutants from domestic sources.
• Consider revising the local limits requirements in the General Pretreatment
•Regulations (§403.5) to address methods for determmmg^Uu^tSjof'ooncem, use of
actual monitoring data instead of default or literaiiEB'v'aIue'si>>>m'e>iB'a.sis of limits, and
other issues.
• Consider developing additional local limits guidance for high-risk nonconservative
organic pollutants (e.g., volatile organic compounds).
• Assess the degree to which corrosion control programs and pipe replacement
programs completed in response to Safe Drinking Water Act requirements may
reduce concentrations of metals in municipal wastewaters.
Recommendation Three: Improve Scientific Basis of Pretreatment Controls
• Continue to emphasize with EPA Regions and States the need for water quality-
based NPDES permits for pretreatment POTWs.
* Continue to train permit writers in methods for incorporating water quality-based
limits and sludge requirements in NPDES permits.
• Target pretreatment POTWs for additional monitoring and reporting, in order to
ascertain the need for additional toxics control, based on data showing actual or
reasonable potential for problems. Target additional POTWs for development of local
pretreatment programs based on these same data sources.
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Establish measures for assessing the environmental effectiveness (e.g., improved
water quality and sludge quality) of local pretreatment programs. Incorporate these
measures into ongoing implementation activities (such as audits, PCIs, or POTW
annual reports).
Continue to develop water quality and sludge quality standards.
Issue guidance to States emphasizing the need to develop water quality standards
and wasteload allocations for toxics of concern. Provide technical assistance as
necessary.
Continue aggressive enforcement of pretreatment standards and requirements at the
local, State, and Federal levels. ,
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ABBREVIATIONS AND ACRONYMS
ACGIH American Conference 'of Governmental Industrial Hygienists
AMSA Association of Metropolitan Sewerage Agencies
BAT Best Available Technology Economically Achievable
BPJ Best Professional Judgement
BMR Baseline Monitoring Report
BPT Best Practicable Technology
BOD Biochemical Oxygen Demand
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
(Superfund) .
CIU Categorical Industrial User .
CWA Clean Water Act
DSS Domestic Sewage Study
EPA U.S. Environmental Protection Agency
GAO General Accounting Office
IDLH Immediately dangerous to life and health
ITD Industrial Technology Division (EPA Office of Water Regulations and
Standards)
IU Industrial User
mgd Million gallons per day
MISA Municipal Industrial Strategy for Abatement
NEDS National Emissions Data System
NIOSH ' National Institute of Occupational Safety and Health
NPDES National Pollutant Discharge Elimination System
NSSS National Sewage Sludge Survey .
NURP National Urban Runoff Program
ORD Office of Research and Development
OSHA Occupational Safety and Health Administration
OWEP Office of Water Enforcement and Permits (EPA)
PASS Pretreatment Audit Summary System ~ • .
PCS Permit Compliance'System
POTW Publicly Owned Treatment Works
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ABBREVIATIONS AND. ACRONYMS (CONTINUED)
PPIC Pollution Prevention Information Clearinghouse
PSES Pretreatment Standards for Existing Sources
RCRA Resource Conservation and Recovery Act
RIA Regulatory Impact Analysis
RNC Reportable Non-Compliance
SDWA Safe Drinking Water Act
SIU Significant Industrial User
SNC Significant Non-Compliance
SS Suspended Solids
STORET Storage and Retrieval Data Base
SU Standard Units
* " ''
TDS Total Dissolved Solids
TOC Toxic Organic Compounds
TTO Total Toxic Organics
TRIS Toxic. Release Inventory System
TSCA Toxic Substances Control Act
TSD Treatment, storage, and disposal operations
TSS Total Suspended Solids
TTO Total Toxic Organics
TWA Time Weighted Average
UST Underground Storage Tank
WERL Wastewater Engineering Research Laboratory
WET Whole Effluent Toxicity
WPCF W|te5 Pollution Control federaton
WWTP
'Mill" I:11:, ii ^'il'Si,::1!1!';]:', i !''';,i' !;i,,ii,!,!i.i
(EPA)
Wastewater treatment Plant
.
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GLOSSARY
Acclimated - A term introduced in the Domestic Sewage Study to characterize removals
achieved by activated sludge treatment plants that have a consistent influent wastewater
feed of each pollutant at 500 parts per billion.
Activated Sludge Process - A (secondary) biological treatment process consisting of an
aeration tank(s) where oxygen is supplied to maintain dissolved oxygen levels, followed by a
clarifier that provides for the removal of solids. .
Allowable Headworks Loading - The maximum pollutant loading that may be received at
the headworks of a specific treatment works calculated to ensure the prevention of
interference or pass through from that pollutant.
Approval Authority - The regulatory agency (the Director in an NPDES State with an
approved. State pretreatment program and the appropriate Regional Administrator in a non-
NPDES State or without an approved State pretreatment program) that is responsible for
overseeing and enforcing the development and implementation of the POTW's local
pretreatment program. (40 CFR 403.3 [c])
Approved Pretreatment Program - A program administered by a POTW that meets the
criteria established in the General Pretreatment Regulations and that has been approved by
the approval authority.. (40 CFR 403.3 [d])
Baseline Monitoring Report (BMR) - A report submitted by categorical industrial users
within 180 days after the effective date of an applicable categorical standard indicating the
compliance status of the user with the categorical standard. (40 CFR 403.129[b])
Best Available Technology (BAT) - A level of technology represented by a higher level of
wastewater treatment technology than required by Best Practicable Technology (BPT). BAT
is based on the best (state of the art) control and treatment measures that have been
developed or are capable of being developed within the appropriate industrial category.
Biochemical Oxygen Demand (BOD) - The rate at which microorganisms use the oxygen in
water or wastewater while stabilizing decomposable organic matter under aerobic conditions.
BOD measurements are used as a measure of the organic strength of wastewater.
Categorical Industrial User - An industrial facility subject to regulation by a national
categorical pretreatment standard established by EPA.
Categorical Standards - Pollutant discharge standards that apply to users in specific
industrial categories determined to be the most significant sources of toxic pollutants
discharged to the Nation's treatment works. These standards are based on the best
technology available to treat the pollutants of concern resulting from the regulated processes.
Categorical pretreatment standards are published by industrial category, each as a separate
regulation. All firms regulated by a particular category are required to comply with these
standards, regardless of where they are located in the United States.
Chemical Abstracts Services - A registry of over 10 million different chemical substances.
Clarifier - A wastewater treatment unit designed to remove settlable solids.
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Comminuters - Devices used to cut wastewater solids to a width of 1/4 to 3/4 inches without
removing them from the wastewater.
Conservative 'Pollutants - Pollutants that are not biodegraded or volatilized at a
wastewater treatment works. ^ _ t ^
Control Authority - A POTW with an approved POTW pretreatment program, or the
approval authority if the POTW does not have an approved POTW pretreatment program.
(40 CFR 403.12[a])
Conventional Pollutants - Biochemical oxygen demand, total suspended solids, fecal
coliform, pH, an
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Hazardous Waste Data Management System (HWDMS) - A data base maintained by
the Office of Solid Waste to track the permit, compliance, and enforcement status of RCRA
hazardous wastehandlers. The data base contains information for more than 90,000 facilities,
which are classified as hazardous waste generators; transporters; treatment, storage, and/or
disposal (TSD) facilities; or nonregulated facilities.
Hydraulic Detention Time - The hydraulic detention time of a particular vessel at a
particular flow may be defined as the flow per unit time divided by the volume of the vessel.
Indirect Discharge - The introduction of pollutants from any nondomestic source into a
POTW. (40 CFfl 403.3[g])
Industrial User - An industrial user is any source of indirect discharge. (40 CFR 403i3 [u])
Interference - A discharge which, alone or in conjunction with a discharge or discharges
from other sources, both:
(A) Inhibits or disrupts the POTW, its treatment process or operations, or its sludge
processes, use or disposal; and
(B) Therefore is a cause of a violation of any requirement of the POTW's NPDES
permit (including an increase in the magnitude or duration of a violation) or of the
prevention of sewage sludge use or disposal in compliance with the following
statutory provisions and regulations or permits issued thereunder (or more
stringent State or local regulations): Section 405 of the Clean Water Act, the
Solid Waste Disposal Act (SWDA) (including Tide n, more commonly referred to
as the Resource Conservation and Recovery Act (RCRA), and including State
regulations contained in any State sludge management plan prepared pursuant to
Subtitle D of SWDA), the Clean Air Act, the Toxic Substances Control Act, and
the Marine Protection, Research and Sanctuaries Act. (40 CFR 403.3[i]).
Lagoons/Stabilization Ponds - Simple basins commonly surrounded by earthen dikes that
provide treatment for waste water through settling and stabilization.
Local Limits - National pollutant discharge limits developed and enforced by the POTW for
specific pollutants of concern to its system to ensure compliance with the prohibited discharge
standards. (40 CFR 403.5[c])
Municipal Industrial Strategy for Abatement (MISA) Study - A study of 37 Canadian
STPs conducted to provide influent and effluent monitoring data to support the development of
monitoring regulations.
National Pollutant Discharge Elimination System (NPDES) - The national program for
issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and
imposing and enforcing pretreatment requirements, under Sections 307, 402, 318, and 405 of
CWA. (Section 122.2)
National Pretreatment Program - The program administered and implemented by EPA
(and approved States) as a subset of the National Pollutant Discharge Elimination System
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(NPDES) program to control discharges of pollutants by industrial and commercial facilities
to POTWs.
National Pretreatment Standard - Any regulation containing pollutant discharge limits
promulgated by the EPA in accordance with Section 307 of the Clean Water Act, which
applies to industrial users. This term includes prohibited discharge standards, categorical
standards, and local limits. (40 CFR 403.3 [j])
National Sewage Sludge Study (NSSS) - A study conducted in 1988 that included sampling
visits to a variety of POTWs. Sewage sludge samples were collected after final processing in
an effort to identify the presence and level of toxic pollutants contained in municipal sewage
sludge.
NEEDS 1988 - An access data base from the biennial NEEDS Survey to estimate the cost
of construction needed by U.S. POTWs.
NEEDS Survey - A biannual assessment of the total cost to the Nation of bringing all
facilities into compliance with the goal of the Clean Water Act to provide a minimum, of
secondary wastewater treatment.
NRDC Consent Decree - A settlement agreement that ended litigation over the toxics
control provisions of the 1972 Federal Water Pollution Control Act (FWPCA) Amendments
frNRDC v. Train. 8ERC2120 [D.D.C. 1976], modified March 1979, October 1982, August
1983, January 1984, July 1984, and January 1985). This agreement required EPA to
promulgate technology-based standards addressing 65 compounds or classes of compounds
for 21 industrial categories. This list of toxic pollutants was adopted by Congress in the 1977
Clean Water Act Amendments.
Pass Through - A discharge that exits the POTW into waters of the United States in
quantities or concentrations that, alone or in conjunction with a discharge or discharges from
other sources, causes a violation of any requirement of the POTW's NPDES permit, including
an increase in the magnitude or duration of the violation. (40 CFR 403.3 [n])
Permit Compliance System (PCS) - A data base used to track information for all NPDES
permitted facilities. This information includes facility 3ata, discharge data, compliance
schedule requirements, enforcement activities, and''compliance' status"^ A subset of this
system, the Pretreatment Program Enforcement Tracking System (PPETS), tracks
pretreatment program implementation information for all municipal facilities with approved
pretreatment programs. • ' '• " •
PRELIM - An EPA computer program designed to assist POTWs in developing technically
based local limits.
Pretreatment - >The reduction of the 'amount of pollutants, the elimination of pollutants, or
the alteration of the nature of pollutant properties in wastewater"-prior''to or in" lieu "of
discharging or otherwise introducing such pollutants into a POTW. The reduction or
alteration may be obtained by physical, chemical, or biological processes, process changes, or
by other means, except that dilution may not be used to substitute for treatment. Appropriate
pretreatment technology includes control equipment, such as equalization tanks or facilities,
for protection against surges or slug loadings that might interfere with or otherwise be
incompatible with the POTW. (40 CFR 403.3[q])
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Pretreatment Audit Summary System (PASS) - An EPA data base designed specifically to
track information obtained during EPA and/or State audits and inspections of local
pretreatment programs. '
Pretreatment Implementation Review Task Force, (PIRT) - A task force established by
EPA in 1984 to review the implementation status of the National Pretreatment Program and
to provide the Agency with recommendations for improving the program.
Pretreatment Standards for Existing Sources (PSES) - Categorical standards and
requirements applicable to industrial sources that began construction prior to the publication
of the proposed pretreatment standards for that industrial category. (See individual
categorical standards in 40 CFR Parts 405-471 for specific dates.)
Primary Treatment - The removal of wastewater solids through sedimentation.
Priority Pollutant - A list of pollutants originally developed during negotiations between the
National Resources Defense Council (NRDC) and EPA and incorporated as a part of a
settlement agreement that ended litigation over the toxics control provisions of the 1972
Federal Water Pollution Control Act (FWPCA) Amendments (NRDC v. Train. 8ERC2120
[D.D.C. 1976], modified. March 1979, October 1982, August 1983, January 1984, and January
1985). The settlement agreement is commonly referred to as the "NRDC Consent Decree."
This list, containing 65 compounds or classes of compounds, including 129 toxic pollutants
(and subsequently amended to 126 pollutants), was adopted by Congress in the 1977 Clean
Water Act Amendments. (40 CFR 403, Appendix B)
Prohibited Discharge Standards - Discharge standards established by EPA, including
general and specific prohibitions. The general prohibitions prohibit pass through and
interference. The specific prohibitions are intended to protect the treatment works and its
operations by prohibiting the discharge of pollutants that will interfere with or pass through
the treatment works^ In particular, they prohibit pollutants that:
(A) Create a fire or explosion, hazard in the sewers or treatment works, specifically
including those with a closed-cup flashpoint of greater than 140°F (60°C)
\ . •, ' ' ^
(B) Are corrosive (with a pH lower than 5.0)
' • . - x
(C) Are solid or viscous in amounts that will cause obstruction to the flow to and/or in
the treatment works, resulting in interference.
(D) Are petroleum oil, nonbiodegradable cutting oil, or mineral oil products in amounts
that will cause interference or pass through
(E) Have a flow rate or concentration that will cause interference
(F) Increase the temperature of the wastewater entering the treatment works to
greater than 104°F (40°C)
(G) Have a fume toxicity in a quantity that may cause acute worker health and safety
problems. (40 CFR 403.5)
Publicly Owned Treatment Works (POTW) - A treatment works, as defined by Section
212 of the Clean Water Act, that is owned by a State or municipality (as defined by Section
501 [4] of the Act). This definition includes any devices and systems used in the, storage,
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treatment, recycling, and reclamation of municipal sewage or industrial wastes of a liquid
nature. It also includes sewers, pipes, and other conveyances only if they convey
wastewater to a POTW treatment plant. The term also means the municipality as defined in
Section 502(4) of the Act, which has jurisdiction over the indirect discharges and discharges
from such a treatment works. (Section 403.3[o])
Removal - The amount by which a pollutant in the influent of the treatment works is reduced
by the treatment processes prior to its discharge by the treatment works. (403.7[a][i])
Removal Credit - A revision to a discharge limit for an industrial user subject to a
categorical pretreatment standard for a particular pollutant discharged to a particular
treatment works based on that treatment works' ability to remove the pollutant to a degree
significantly greater than that considered in the development of the standard. The POTW
must apply to the approval authority for authorization to grant a removal credit to its affected
industrial users. Such authorization'will only be granted where the POTW can demonstrate
that the revised discharge limit will not endanger its compliance with all applicable
requirements, including water quality standards, NPDES permit conditions, and sludge reuse
and/or disposal requirements. (40 CFR 403.7)
Reportable Non-Compliance (RNC) - Criteria developed by OWEP that are used to
evaluate local program implementation and that provide the framework for the definition of
reportable noncompliance. The criteria should be used by EPA Regions and approved States
to report POTW noncompliance with pretreatment requirements on the QNCR (Quarterly
Noncompliance Report). The criteria are:
• POTW establishment of insignificant user control mechanisms
, • POTW compliance monitoring and inspections
•. POTW enforcement or pretreatment standards and reporting requirements
• POTW reporting to the approval authority
• Other POTW implementation requirements.
Screening - A preliminary wastewater treatment unit found at or near the headworks of the
treatment works that consists of parallel bars or gratings with uniform spacing designed to
remove larger debris and solids from the wastewater. •
Secondary Sedimentation - A function of the secondary clarifier that is designed to remove
the biomass from the wastestream, thereby allowing for recycling and wasting of solids.
Secondary Treatment - Treatment processes, including activated,sludge, trickling filters,
and lagoon systems, that are designed to break down pollutants in the wastewater tjjrough
biochemical processes. The level of treatment required for secondary treatment is defined in
40 CFR Part 133:
Significant Industrial User (SIU) - Any industrial user that meets any of the following
criteria: ' ' '
(A) Is subject to categorical pretreatment standards
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(B) Discharges an average of 25,000 gallons or more per day of process wastewater
to the treatment works ' .
(C) Contributes a process wastestream that makes up 5 percent or more of the
hydraulic or organic capacity of the treatment works
(D) Is determined by the POTW to have a reasonable potential for adversely affecting
the treatment works' operation or for violating any pretreatment standard or
requirement. (40 CFR 403.3[t])
Significant Non-Compliance (SNC) - Criteria used by control and approval authorities to
identify important violations and/or patterns of noncompliance. These criteria are used to
establish enforcement priorities and comply with special reporting requirements. An
industrial user is in significant non-compliance if its violation meets one or more of the
following criteria: (A) Chronic violations of wastewater discharge limits, defined here as
those in which 66'percent or more of all of the measurements taken during a 6-month period
exceed (by any magnitude) the daily maximum limit or the average limit for the same
pollutant parameter, (B) Technical Review Criteria (TRC) violations, defined here as those in
.which 33 percent or more of all of the measurements for each pollutant parameter taken during
a 6-month period equal or exceed the product of the daily maximum limit or the "average limit
multiplied by the applicable TRC; (C) Any other violation of a pretreatment effluent limit
(daily maximum or longer term average) that the Control Authority determines has caused,
alone or in combination with other discharges, interference or pass through (including
endangering the health of the POTW personnel or the general public); (D) Any discharge of a
pollutant that has caused imminent endangerment to human health, welfare, or to the
environment or has resulted in the POTW's exercise of its emergency authority under
paragraph (f)(l)(vi)(B) of this section to halt or prevent such a discharge; (E) Failure to
meet, within 90 days after the schedule date, a compliance schedule milestone contained in a
local control mechanism or enforcement order for starting construction, completing
construction, or attaining final compliance; (F) Failure to provide, within 30 days after the due
date, required reports, such as baseline monitoring reports, periodic self-monitoring reports,
and reports on compliance with compliance schedules; (G) Failure to accurately report
noncompliance; (H) Any other violation or group of violations that the Control Authority
determines will adversely affect the operation or implementation of the local pretreatment
program.
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Solvent Recycling Industry (SRI) - Commercial facilities that recycle spent solvents
resulting from manufacturing processes or cleaning operations located at other sites. SRI
.facilities do not include recovery operations that are an integral part of a main process, such
as solvent refining or vegetable oil manufacturing, and they do not include operations added
on to a process, such as surface coating industries ithat reclaim spent solvents reused onsite.
STORETV (Storage and Retrieval Data Base) - A data base that includes water-related
environmental data for all 50 States.
Total Toxic Organics (TTO) - Total toxic organics, which is the summation of all
quantifiable values greater than 0.01 milligrams per liter for a long list of toxic pollutants
identified under individual categorical standards.
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Toxic Pollutant - For purposes of this report, any pollutant, including any pollutant listed as
toxic under Section. 307(a)(l) of the Clean Water Act (priority pollutants) and other
pollutants as reported by the various data sources used in this report.
Toxic Release Inventory System (TRIS) - Established under Section 313 of the 1986
Emergency Planning and Community Right to Know Act, TRIS is a data source used to
identify toxic pollutants being discharged by industrial and commercial sources into the
environment, including discharges to POTWs.
Trickling Filter - A secondary treatment process consisting of a bed of coarse inert
materials (natural or synthetic) over which the primary clarifier effluent is uniformly
distributed. The inert materials provide a surface for the growth of bioinass that treats the
wastewater. '
Used Oil Reclamation and Re-Refining Industry - Consists of approximately 68 used oil
recycling businesses. The industry can be subdivided into two facility classes based on the
sophistication of the processing technology arid the purity of the product.
Whole Effluent Toxicity (WET) - The aggregate toxic effect of an effluent measured directly
by a toxicity test (40 CFR 122.21 [j])
mi in
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