Unfed States
wnbntnental Protect.
Office of Water (4303)
Washington, DC 20460
EPA-821-B-00-005
December 2000
development Document
For The Proposed Effluent
Limitations Guidelines And
Standards For The Metal
Products & Machinery
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Development Document
For The Proposed Effluent Limitations
Guidelines and Standards
For The
Metal Products & Machinery
Point Source Category
Carol M. Browner
Administrator
J. Charles Fox
Assistant Administrator, Office of Water
Geoffrey H. Grubbs
Director, Office of Science and Technology
Sheila E. Frace
Director, Engineering and Analysis Division
Marvin Rubin
Chief, Energy Branch
Shari Z. Barash
Project Manager
Michael C. Ebner
Assistant Project Manager
Lynne Tudor
Project Economist
Helen Jacobs
Project Statistician
December 2000
U.S. Environmental Protection Agency
Office of Water
Washington, DC 20460
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ACKNOWLEDGMENTS AND DISCLAIMER
The Agency would like to acknowledge the contributions of Shari Barash, Mike
Ebner, Marvin Rubin, Helen Jacobs, Lynne Tudor, Karen Clark, and Beverly Randolph to
development of this technical document. In addition, EPA acknowledges the contribution
of Eastern Research Group, Westat, Abt Associates, and Science Applications International
Corporation.
Neither the United States government nor any of its employees, contractors,
subcontractors, or other employees makes any warranty, expressed or implied, or assumes
any legal liability or responsibility for any third party's use of, or the results of such use of,
any information, apparatus, product, or process discussed in this report, or represents that its
use by such a third party would not infringe on privately owned rights.
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TABLE OF CONTENTS
Page
1.0 SUMMARY AND SCOPE OF THE REGULATION 1-1
1.1 Overview of the MP&M Point Source Category 1-1
1.2 Applicability of MP&M and Overlap with Other Effluent
Guidelines 1-3
1.3 Proposed Effluent Limitations Guidelines and Standards 1-6
2.0 BACKGROUND 2-1
2.1 Legal Authority 2-1
2.2 Regulatory Background 2-1
2.2.1 Clean Water Act 2-1
2.2.2 Section 304(m) Requirements 2-4
2.2.3 Pollution Prevention Act 2-5
2.2.4 Regulatory Flexibility Act (RFA) as Amended by the Small
Business Regulatory Enforcement Fairness Act of 1996
(SBREFA) 2-5
2.2.5 Regulatory History of the Metals Industry 2-7
3.0 DATA COLLECTION ACTIVITIES 3-1
3.1 Industry Questionnaires 3-1
3.1.1 The 1989 Industry Surveys 3-1
3.1.1.1 1989 Screener Survey 3-2
3.1.1.2 1989 Detailed Survey 3-7
3.1.2 The 1996 Industry Surveys 3-11
3.1.2.1 1996 Screener Surveys 3-12
3.1.2.2 1996 Long Detailed Survey 3-14
3.1.2.3 1996 Short Detailed Survey 3-18
3.1.2.4 1996 Municipality Detailed Survey 3-20
3.1.2.5 1996 Federal Facilities Detailed Survey 3-22
3.1.2.6 1997 Iron and Steel Industry Short Survey Data .... 3-23
3.1.2.7 1996 Publicly Owned Treatment Works (POTW)
Detailed Survey 3-24
3.2 Site Visits 3-26
3.2.1 Criteria for Site Selection 3-26
3.2.2 Information Collected 3-28
3.3 Wastewater and Solid Waste Sampling 3-28
3.3.1 Criteria for Site Selection 3-29
3.3.2 Information Collected 3-30
3.3.3 Sample Collection and Analysis 3-30
3.4 Other Sampling Data 3-37
3.5 Other Industry-Supplied Data 3-37
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TABLE OF CONTENTS (Continued)
Page
3.6 Other Data Sources 3-38
3.6.1 EPA/EAD Databases 3-38
3.6.2 Fate of Priority Pollutants in Publicly Owned Treatment
Works Database 3-39
3.6.3 National Risk Management Research Laboratory (NRMRL)
Treatability Database 3-39
3.6.4 The Domestic Sewage Study 3-40
3.6.5 Toxics Release Inventory (TRI) Database 3-40
3.7 References 3-41
4.0 INDUSTRY DESCRIPTION 4-1
4.1 Overview of the Industry 4-1
4.1.1 Number and Size of MP&M Sites 4-1
4.1.2 Geographic Distribution 4-2
4.1.3 Wastewater-Discharging Sites 4-3
4.1.4 Non-Wastewater-Discharging Sites 4-7
4.2 General Discussion of MP&M Processes 4-10
4.2.1 Types of Unit Operations Performed 4-10
4.2.2 MP&M Unit Operations and Rinses 4-13
4.2.3 Metal Types Processed 4-30
4.2.4 Waste water Discharge Volumes Generated 4-31
4.3 Trends in the Industry 4-35
4.4 References 4-35
5.0 WASTEWATER CHARACTERISTICS 5-1
5.1 Hexavalent Chromium-Bearing Wastewater 5-1
5.1.1 Unit Operations Generating Hexavalent Chromium-Bearing
Wastewater 5-2
5.1.2 Chromium-Bearing Raw Wastewater Characteristics 5-3
5.2 Cyanide-Bearing Wastewater 5-4
5.2.1 Unit Operations Generating Cyanide-Bearing Wastewater .... 5-4
5.2.2 Cyanide-Bearing Raw Wastewater Characteristics 5-5
5.3 Oil-Bearing and Organic Pollutant-Bearing Wastewater 5-6
5.3.1 Unit Operations Generating Oil-Bearing and/or Organic
Pollutant-Bearing Wastewater 5-6
5.3.2 Oil-Bearing and Organic Pollutant-Bearing Raw Wastewater
Characteristics 5-16
5.4 Chelated Metal-Bearing Wastewater 5-20
5.4.1 Unit Operations Generating Chelated Metal-Bearing
Wastewater 5-20
5.4.2 Chelation-Breaking Raw Wastewater Characteristics 5-20
11
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TABLE OF CONTENTS (Continued)
Page
5.5 General Metal-Bearing Wastewater 5-21
5.5.1 Unit Operations Generating General Metal-Bearing
Wastewater 5-21
5.5.2 General Metal-Bearing Raw Wastewater Characteristics .... 5-29
6.0 INDUSTRY SUBCATEGORIZATION 6-1
6.1 Methodology and Factors Considered for Basis of Subcategorization . 6-1
6.1.1 Factors Contributing to Subcategorization 6-2
6.1.2 Factors That are not a Basis for MP&M Subcategorization ... 6-9
6.2 General Description of Facilities in Each Subcategory 6-13
6.2.1 General Metals Subcategory 6-13
6.2.2 Metal Finishing Job Shops Subcategory 6-14
6.2.3 Non-Chromium Anodizing Subcategory 6-14
6.2.4 Printed Wiring Board Subcategory 6-15
6.2.5 Steel Forming and Finishing 6-15
6.2.6 Oily Wastes Subcategory 6-16
6.2.7 Railroad Line Maintenance Subcategory 6-17
6.2.8 Shipbuilding Dry Dock Subcategory 6-18
7.0 SELECTION OF POLLUTANT PARAMETERS 7-1
7.1 Identification of Pollutant Parameters of Concern 7-3
7.2 Pollutants Proposed to be Regulated for Direct Dischargers 7-13
7.2.1 Regulated Pollutant Analysis for Direct Dischargers in the
Metal-Bearing Subcategories 7-13
7.2.1.1 General Metals Subcategory 7-20
7.2.1.2 Metal Finishing Job Shops Subcategory 7-20
7.2.1.3 Non-Chromium Anodizing Subcategory 7-20
7.2.1.4 Printed Wiring Board Subcategory 7-21
7.2.1.5 Steel Forming and Finishing Subcategory 7-21
7.2.2 Regulated Pollutant Analysis for Direct Dischargers in the
Oil-Bearing Subcategories 7-21
7.2.2.1 Oily Wastes Subcategory 7-26
7.2.2.2 Railroad Line Maintenance Subcategory 7-27
7.2.2.3 Shipbuilding Dry Dock Subcategory 7-27
7.3 Pollutants Proposed to be Regulated for Indirect Dischargers 7-27
7.3.1 Pass-through Analysis for Indirect Dischargers 7-28
7.3.2 Pass-through Analysis Results for Existing Sources 7-31
7.3.3 Pass-through Analysis Results for New Sources 7-32
7.4 References 7-34
in
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TABLE OF CONTENTS (Continued)
Page
8.0 POLLUTION PREVENTION PRACTICES AND WASTEWATER TREATMENT
TECHNOLOGIES 8-1
8.1 Pollution Prevention Practices 8-1
8.1.1 Flow Reduction Practices 8-1
8.1.1.1 Rinse Tank Design and Innovative Configurations . . 8-1
8.1.1.2 Additional Rinse Design Elements 8-4
8.1.1.3 Rinse Water Use Control 8-5
8.1.1.4 Pollution Prevention for Process Baths 8-6
8.1.2 In-Process Pollution Prevention Technologies 8-7
8.1.2.1 Activated Carbon Adsorption 8-7
8.1.2.2 Carbonate "Freezing" 8-8
8.1.2.3 Centrifugation and Pasteurization of Machining
Coolants 8-8
8.1.2.4 Centrifugation and Recycling of Painting Water
Curtains 8-9
8.1.2.5 Electrodialysis 8-11
8.1.2.6 Electrolytic Recovery 8-11
8.1.2.7 Evaporation 8-13
8.1.2.8 Filtration 8-13
8.1.2.9 Ion Exchange (in-process) 8-15
8.1.2.10 Reverse Osmosis 8-17
8.1.3 Other Types of Pollution Prevention Practices 8-19
8.2 Preliminary Treatment of Segregated Wastewater Streams 8-20
8.2.1 Chromium-Bearing Wastewater 8-20
8.2.2 Concentrated Metal-Bearing Wastewater 8-22
8.2.3 Cyanide-Bearing Wastewater 8-22
8.2.3.1 Alkaline Chlorination 8-22
8.2.3.2 Ozone Oxidation 8-23
8.2.4 Chelated Metal-Bearing Wastewater 8-24
8.2.4.1 Reduction to Elemental Metal 8-24
8.2.4.2 Precipitation of an Insoluble Compound 8-25
8.2.4.3 Physical Separation 8-26
8.2.5 Oil-Bearing Wastewater 8-26
8.2.5.1 Chemical Emulsion Breaking 8-26
8.2.5.2 Oil Skimming 8-28
8.2.5.3 Flotation of Oils or Solids 8-31
8.2.5.4 Ultrafiltration 8-32
8.3 End-of-Pipe Wastewater and Sludge Treatment Technologies 8-33
8.3.1 Metals Removal 8-33
8.3.1.1 Gravity Clarification for Solids Removal 8-38
8.3.1.2 Microfiltration for Solids Removal 8-40
8.3.2 Oil Removal 8-41
IV
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TABLE OF CONTENTS (Continued)
Page
8.3.3 Polishing Technologies 8-41
8.3.3.1 Multimedia Filtration 8-41
8.3.3.2 Activated Carbon Adsorption 8-42
8.3.3.3 Reverse Osmosis 8-43
8.3.3.4 Ion Exchange 8-43
8.3.4 Sludge Handling 8-43
8.3.4.1 Gravity Thickening 8-43
8.3.4.2 Pressure Filtration 8-44
8.3.4.3 Vacuum Filtration 8-45
8.3.4.4 Sludge Drying 8-47
8.4 References 8-47
9.0 TECHNOLOGY OPTIONS 9-1
9.1 Technology Evaluation Methods 9-1
9.2 Technology Options 9-3
9.2.1 General Metals, Metal Finishing Job Shops, Printed Wiring
Boards, Steel Forming and Finishing, and Non-Chromium
Anodizing Subcategories 9-3
9.2.2 Oily Wastes Subcategory 9-7
9.2.3 Shipbuilding Dry Dock and Railroad Line Maintenance
Subcategories 9-8
9.3 References 9-9
10.0 LONG-TERM AVERAGES AND VARIABILITY FACTORS 10-1
10.1 Sources of Technology Performance Data 10-2
10.1.1 EPA Sampling Program 10-2
10.1.2 Sampling Episodes Conducted by Industry and Local Sanitation
Districts 10-3
10.1.3 Industry-Supplied Effluent Monitoring Data 10-3
10.2 Evaluation of Treatment Effectiveness 10-4
10.2.1 Identification of Pollutants Not Present in the Raw
Wastewater at Sufficient Concentrations to Evaluate
Treatment Effectiveness 10-6
10.2.2 Assessment of General Treatment System Performance 10-8
10.2.3 Identification of Process Upsets That Could Affect Data
Quality 10-10
10.2.4 Identification of Wastewater Treatment Chemicals 10-12
10.3 Development of Long-Term Averages and Variability Factors 10-12
10.3.1 Derivation of the Proposed Limitations 10-12
10.3.2 Steps Used to Derive Concentration-Based Limitations .... 10-14
10.3.3 Modified Delta-Lognormal Model 10-14
10.3.4 Estimation Under the Modified Delta-Lognormal Model ... 10-16
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TABLE OF CONTENTS (Continued)
Page
10.3.5 Estimation of LTAs and VFs (Data Groups) 10-17
10.3.6 Estimation of LTAs 10-17
10.3.7 Estimation of VFs 10-18
10.3.7.1 Estimation of 1-day VFs 10-18
10.3.7.2 Estimation of 4-day VFs 10-20
10.4 Methodology for Development of TOP Long-Term Averages and
Variability Factors 10-23
11.0 COSTS OF TECHNOLOGY BASES FOR REGULATIONS 11-1
11.1 Summary of Costs 11-2
11.2 Model Site Development 11-5
11.2.1 Site Selection 11-5
11.2.2 Wastewater Stream Parameters 11-5
11.2.3 Pollutant Concentrations 11-6
11.2.4 Technology inPlace 11-7
11.3 Methodology for Estimating Costs 11-9
11.3.1 Components of Cost 11-9
11.3.2 Sources and Standardization of Cost Data 11-11
11.3.3 MP&M Design and Cost Model 11-13
11.3.4 General Assumptions Made During the Costing Effort 11-19
11.4 Design and Costs of Individual Technologies 11-23
11.4.1 Countercurrent Cascade Rinsing 11-23
11.4.2 Centrifugati on and Pasteurization of Machining Coolant ... 11-30
11.4.3 Centrifugation of Painting Water Curtains 11-30
11.4.4 Contract Hauling 11-31
11.4.5 Feed Systems 11-32
11.4.6 Chemical Emulsion Breaking and Gravity Oil/Water
Separation 11-33
11.4.7 Dissolved Air Flotation 11-34
11.4.8 Ultrafiltration System for Oil Removal 11-35
11.4.9 Batch Oil Emulsion Breaking with Gravity Flotation 11-36
11.4.10 Chemical Reduction of Hexavalent Chromium 11-36
11.4.11 Cyanide Destruction 11-37
11.4.12 Chemical Reduction/Precipitation of Chelated Metals 11-38
11.4.13 Chemical Precipitation 11-38
11.4.14 Slant-Plate Clarifier 11-39
11.4.15 Multimedia Filtration 11-40
11.4.16 Microfiltration for Solids Removal 11-40
11.4.17 Sludge Thickening 11-41
11.4.18 Sludge Pressure Filtration 11-41
11.5 References 11-42
VI
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TABLE OF CONTENTS (Continued)
Page
12.0 POLLUTANT LOADING AND REDUCTION ESTIMATES 12-1
12.1 Estimation of Unit Operation Pollutant Concentrations 12-3
12.1.1 Calculate Pollutant Concentrations for Each Sampling
Point 12-3
12.1.2 Estimate Pollutant Concentrations for Each Unit Operation .. 12-4
12.2 Calculation of Industry Pollutant Loadings and Reductions 12-4
12.2.1 Industry Raw Wastewater Pollutant Loadings 12-5
12.2.2 Industry Baseline Pollutant Loadings 12-5
12.2.3 Option-Specific Industry Pollutant Loadings and Pollutant
Reductions 12-6
13.0 NON-WATER QUALITY IMPACTS 13-1
13.1 Energy Requirements 13-1
13.2 Air Emissions Impacts 13-2
13.3 Solid Waste Generation 13-3
13.3.1 Wastewater Treatment Sludge 13-3
13.3.2 Waste Oil 13-5
13.4 References 13-6
14.0 EFFLUENT LIMITATIONS AND STANDARDS 14-1
14.1 Best Practicable Control Technology Currently Available (BPT) .... 14-1
14.1.1 BPT Technology Selection for General Metals
Subcategory 14-5
14.1.2 BPT Technology Selection for Metal Finishing Job Shops
Subcategory 14-7
14.1.3 BPT Technology Selection for Non-Chromium Anodizing
Subcategory 14-10
14.1.4 BPT Technology Selection for Printed Wiring Board
Subcategory 14-13
14.1.5 BPT Technology Selection for Steel Forming and
Finishing Subcategory 14-16
14.1.6 BPT Technology Selection for the Oily Wastes
Subcategory 14-25
14.1.7 BPT Technology Selection for the Railroad Line
Maintenance Subcategory 14-27
14.1.8 BPT Technology Selection for the Shipbuilding Dry Dock
Subcategory 14-29
14.2 Best Conventional Pollutant Control Technology (BCT) 14-31
14.2.1 BCT Option for Metal-Bearing Wastewater 14-31
14.2.2 BCT Option for Oil-Bearing Wastewater 14-32
14.3 Best Available Technology Economically Achievable (BAT) 14-32
14.3.1 BAT Technology Selection for the General Metals
vn
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TABLE OF CONTENTS (Continued)
Page
Subcategory 14-33
14.3.2 BAT Technology Selection for the Metal Finishing Job
Shops Subcategory 14-34
14.3.3 BAT Technology Selection for the Non-Chromium
Anodizing Subcategory 14-34
14.3.4 BAT Technology Selection for the Printed Wiring Board
Subcategory 14-35
14.3.5 BAT Technology Selection for the Steel Forming and
Finishing Subcategory 14-35
14.3.6 BAT Technology Selection for the Oily Wastes
Subcategory 14-36
14.3.7 BAT Technology Selection for the Railroad Line
Maintenance Subcategory 14-36
14.3.8 BAT Technology Selection for the Shipbuilding Dry Dock
Subcategory 14-37
14.4 Pretreatment Standards for Existing Sources (PSES) 14-37
14.4.1 Overview of Options and Low-Flow Exclusions 14-38
14.4.2 PSES for General Metals Subcategory 14-40
14.4.3 PSES for the Metal Finishing Job Shops Subcategory 14-44
14.4.4 PSES for the Non-Chromium Anodizing Subcategory 14-48
14.4.5 PSES for the Printed Wiring Board Subcategory 14-48
14.4.6 PSES for the Steel Forming and Finishing Subcategory .... 14-51
14.4.7 PSES for the Oily Wastes Subcategory 14-58
14.4.8 PSES for the Railroad Line Maintenance Subcategory 14-61
14.4.9 PSES for the Shipbuilding Dry Dock Subcategory 14-61
14.5 New Source Performance Standards (NSPS) 14-61
14.5.1 NSPS for the General Metals Subcategory 14-62
14.5.2 NSPS for the Metal Finishing Job Shops Subcategory 14-63
14.5.3 NSPS for the Non-Chromium Anodizing Subcategory 14-66
14.5.4 NSPS for the Printed Wiring Board Subcategory 14-67
14.5.5 NSPS for the Steel Forming and Finishing Subcategory .... 14-68
14.5.6 NSPS for the Oily Wastes Subcategory 14-74
14.5.7 NSPS for the Railroad Line Maintenance Subcategory 14-74
14.5.8 NSPS for the Shipbuilding Dry Dock Subcategory 14-75
14.6 Pretreatment Standards for New Sources (PSNS) 14-75
14.6.1 PSNS for the General Metals Subcategory 14-76
14.6.2 PSNS for the Metal Finishing Job Shops Subcategory 14-77
14.6.3 PSNS for the Non-Chromium Anodizing Subcategory .... 14-79
14.6.4 PSNS for the Printed Wiring Board Subcategory 14-79
14.6.5 PSNS for the Steel Forming and Finishing Subcategory .... 14-80
14.6.6 PSNS for the Oily Wastes Subcategory 14-86
14.6.7 PSNS for the Railroad Line Maintenance Subcategory 14-86
Vlll
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TABLE OF CONTENTS (Continued)
Page
14.6.8 PSNS for the Shipbuilding Dry Dock Subcategory 14-86
15.0 PERMITTING GUIDANCE 15-1
15.1 Background 15-1
15.2 Implementing the MP&M Effluent Guidelines 15-5
15.2.1 Application of the Building Block Approach for Direct
Dischargers 15-7
15.2.2 Application of the Combined Wastestream Formula for
Indirect Dischargers 15-10
15.2.3 Production-Based Limits for the Steel Forming and
Finishing Subcategory 15-12
15.2.4 Use of Site-Specific Historical Flow Data to Calculate
Flow-Based Mass Limitations 15-15
15.2.5 Use of General MP&M Industry Flow Data to Develop
Flow-Based Mass Limitations 15-16
15.2.6 Estimating Reasonable Production Rates 15-19
15.2.7 Monitoring Flexibility 15-24
15.3 Flow Guidance for Surface Treatment Rinsing Operations 15-27
15.3.1 Identification of Sites With Pollution Prevention and
Water Conservation Practices 15-27
15.3.2 Influences on Flow Rates 15-38
15.3.3 Guidance for PNF Selection 15-39
15.4 Flow Guidance for Machining Operations 15-43
15.4.1 Identification of Sites With Pollution Prevention and
Water Conservation Practices 15-43
15.4.2 Influences on Flow Rates 15-48
15.4.3 Guidance for PNF Selection 15-49
15.5 Flow Guidance for Painting Operations 15-50
15.5.1 Identification of Sites With Pollution Prevention and
Water Conservation Practices 15-51
15.5.2 Influences on Flow Rates 15-56
15.5.3 Guidance for PNF Selection 15-57
15.6 Flow Guidance for Cleaning Operations 15-58
15.6.1 Identification of Sites With Pollution Prevention and
Water Conservation Practices 15-58
15.6.2 Influences on Flow Rates 15-63
15.6.3 Guidance for PNF Selection 15-65
15.7 References 15-66
16.0 GLOSSARY/LIST OF ACRONYMS 16-1
IX
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LIST OF TABLES
Page
1-1 Clarification of Coverage by MP&M Subcategory 1-4
1-2 Typical Unit Operations Performed at MP&M Sites 1-7
2-1 Summary of Regulatory Levels of Control 2-4
2-2 Summary of Metals Industry Effluent Guidelines 2-7
3-1 1989 and 1996 MP&M Survey Mailout Results 3-4
3-2 Summary of 1996 Detailed Survey Information by Question Number 3-16
3-3 Number of Sites Visited Within Each MP&M Sector 3-26
3-4 Number of Sites Sampled Within Each MP&M Sector 3-29
3-5 Metal Constituents Measured Under the MP&M Sampling Program 3-32
3-6 Organic Constituents Measured Under the MP&M Sampling Program 3-33
3-7 Additional Parameters Measured Under the MP&M Sampling Program .... 3-36
4-1 MP&M Wastewater-Discharging Sites by Sector 4-4
4-2 MP&M Unit Operations Listed by Type 4-12
4-3 Typical Unit Operations Performed at MP&M Sites 4-14
4-4 Additional Water-Using Unit Operations Performed at MP&M Sites 4-30
4-5 Number of MP&M Sites Discharging Process Wastewater by Unit Operation
and Flow 4-32
5-1 Number of Process and Rinse Samples for Unit Operations That Generate
Hexavalent Chromium-Bearing Wastewater 5-2
5-2 Summary of Analytical Data for Chromium From Unit Operations and Rinses
Generating Chromium-Bearing Wastewater 5-3
5-3 Summary of Analytical Data for Chromium in Chromium-Bearing Raw
Wastewater at Influent to Hexavalent Chromium Treatment 5-3
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LIST OF TABLES (Continued)
Page
5-4 Number of Process and Rinse Samples for Unit Operations That Generate
Cyanide-Bearing Wastewater 5-4
5-5 Summary of Analytical Data for Cyanide from Unit Operations and Rinses
Generating Cyanide-Bearing Wastewater 5-5
5-6 Summary of Analytical Data for Cyanide in Cyanide-Bearing Raw
Wastewater at Influent to Cyanide Treatment 5-5
5-7 Number of Process and Rinse Samples For Unit Operations That Generate
Oil-Bearing and/or Organic Pollutant-Bearing Wastewater 5-7
5-8 Analytical Data for Unit Operations Generating Oil-Bearing and/or
Organic-Bearing Wastewater 5-8
5-9 Analytical Data for Rinses Generating Oil-Bearing and/or Organic-Bearing
Wastewater 5-13
5-10 Analytical Data for Oil-Bearing and Organic Pollutant-Bearing Raw
Wastewater Streams at Influent to Oil/Water Separation 5-16
5-11 Number of Process and Rinse Samples From Unit Operations That Generate
General Metal-Bearing Wastewater 5-22
5-12 Analytical Data from Unit Operations Generating General Metal-Bearing
Wastewater 5-23
5-13 Analytical Data from Rinses Generating General Metal-Bearing Wastewater 5-27
5-14 Analytical Data for General Metal-Bearing Treatment Influent Wastewater
Streams 5-31
6-1 Proposed Subcategories 6-2
6-2 Percentage of Facilities Using Multiple Metal Types by Subcategory 6-4
6-3 Percentage of MP&M Facilities by Subcategory Using Each Metal Type .... 6-6
6-4 Unit Operations Performed by Oily Wastes Facilities 6-8
7-1 Priority Pollutant List 7-2
XI
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LIST OF TABLES (Continued)
Page
7-2 Pollutant Parameters Not Detected in Any Samples Collected During the
MP&M Sampling Program 7-5
7-3 Pollutant Parameters Detected in Less Than Three Samples Collected
During the MP&M Sampling Program 7-7
7-4 Pollutant Parameters Detected at Average Concentrations of Less Than Five
Times the Minimum Level During the MP&M Sampling Program 7-8
7-5 Pollutant Parameters Selected for Further Consideration Under the MP&M
Proposed Rule 7-9
7-6 Pollutants Not Selected for Proposed Regulation for the Metal-Bearing
Subcategories Because They Are Controlled Through the Regulation of
Other Pollutants 7-14
7-7 Pollutants Not Selected for Proposed Regulation for the Metal-Bearing
Subcategories Because They Are Present in Only Trace Amounts and/or Are
Not Likely to Cause Toxic Effects 7-15
7-8 Pollutants Not Selected for Proposed Regulation for the Metal-Bearing
Subcategories Because They May Serve as Treatment Chemicals in the
MP&M Industry 7-16
7-9 Pollutants Not Selected for Proposed Regulation for the Metal-Bearing
Subcategories Because They Are Not Controlled by the Selected BPT/BAT
Technology 7-17
7-10 64 Remaining Pollutants Considered for Proposed Regulation for the Metal-
Bearing Subcategories 7-18
7-11 Pollutants Not Selected for Proposed Regulation for the Oil-Bearing
Subcategories Because They Are Controlled Through the Regulation of
Other Pollutants 7-22
7-12 Pollutants Not Selected for Proposed Regulation for the Oil-Bearing
Subcategories Because They Are Present in Only Trace Amounts and/or Are
Not Likely to Cause Toxic Effects 7-23
7-13 Pollutants Not Selected for Proposed Regulation for the Oil-Bearing
Subcategories Because They May Serve as Treatment Chemicals in the
MP&M Industry 7-24
xn
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LIST OF TABLES (Continued)
Page
7-14 Pollutants Not Selected for Proposed Regulation for the Oil-Bearing
Subcategories Because They Are Not Controlled by the Selected BPT/BAT
Technology 7-25
7-15 49 Remaining Pollutants Considered for Proposed Regulation for the Oil-
Bearing Subcategories 7-25
7-16 Pass-Through Analysis Results for Existing Sources for Metal-Bearing
Wastewater Subcategories 7-31
7-17 Pass-Through Analysis Results for New Sources for Metal-Bearing
Wastewater Subcategories 7-33
9-1 EMH Tier 1 - MP&M Source Reduction and Pollution Prevention
Technologies 9-10
9-2 EMH Tier 2 - MP&M Recycling Technologies 9-13
9-3 EMH Tiers 3 and 4 - MP&M End-of-Pipe Treatment and Disposal
Technologies 9-15
9-4 Technology Options by Subcategory 9-20
10-1 Number of Evaluated Treatment Systems for Each Subcategory 10-24
10-2 Influent and Effluent Data Points from EPA Sampling Episodes 10-25
10-3 Influent and Effluent Data Points from Industry and Local Sanitation
District Sampling Episodes 10-26
10-4 Industry-Supplied Effluent Monitoring Data 10-26
10-5 Number of Effluent Data Points Flagged for Each MP&M Technology
Option 10-27
10-6A MP&M Technology Effectiveness Concentrations for Total and Amenable
Cyanide Destruction 10-28
10-6B MP&M Technology Effectiveness Concentrations for General Metals and
Steel Forming and Finishing Subcategories (Option 2) 10-29
Xlll
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LIST OF TABLES (Continued)
Page
10-6C MP&M Technology Effectiveness Concentrations for General Metals and
Steel Forming and Finishing Subcategory (Option 4) 10-33
10-6D MP&M Technology Effectiveness Concentrations for Metal Finishing Job
Shops Subcategory (Option 2) 10-34
10-6E MP&M Technology Effectiveness Concentrations for Nonchromium
Anodizers Subcategory (Option 2) 10-36
10-6F MP&M Technology Effectiveness Concentrations for Printed Wiring
Boards Subcategory (Option 2) 10-36
10-6G MP&M Technology Effectiveness Concentrations for Printed Wiring
Boards Subcategory (Option 4) 10-37
10-6H MP&M Technology Effectiveness Concentrations for Oily Wastes
Subcategory (Option 6) 10-37
10-61 MP&M Technology Effectiveness Concentrations for Railroad Line
Maintenance Subcategory (Option 10) 10-38
10-6J MP&M Technology Effectiveness Concentrations for Shipbuilding and
Drydock Subcategory (Option 10) 10-39
10-7 Calculation of Total Organics Parameter (TOP) Limit 10-40
10-8A Episode-Level Long-Term Averages and Variability Factors for Total
and Amenable Cyanide Destruction (All Options for Applicable
Subcategories) 10-42
10-8B Episode-Level Long-Term Averages and Variability Factors for
General Metals and Steel Forming and Finishing Subcategories
(Option 2) 10-43
10-8C Episode-Level Long-Term Averages and Variability Factors for
General Metals and Steel Forming and Finishing Subcategories (Option 4) . 10-47
10-8D Episode-Level Long-Term Averages and Variability Factors for
Metal Finishing Job Shops Subcategory (Option 2) 10-49
10-8E Episode-Level Long-Term Averages and Variability Factors for
Metal Finishing Job Shops (Option 4) 10-51
xiv
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LIST OF TABLES (Continued)
Page
10-8F Episode-Level Long-Term Averages and Variability Factors for
Nonchromium Anodizing Subcategory (Option 2) 10-53
10-8G Episode-Level Long-Term Averages and Variability Factors for
Printed Wiring Boards Subcategory (Option 2) 10-55
10-8H Episode-Level Long-Term Averages and Variability Factors for
Printed Wiring Boards Subcategory (Option 4) 10-57
10-81 Episode-Level Long-Term Averages and Variability Factors for
Oily Waste Subcategory (Option 6) 10-58
10-8J Railroad Line Maintenance Subcategory (Option 10) 10-59
10-8K Shipbuilding Dry Dock Subcategory (Option 10) 10-59
10-9A Pollutant-Level Long-term Averages, Variability Factors and Limitations
for General Metals Option 2 10-60
10-9B Pollutant-Level Long-term Averages, Variability Factors and Limitations
for General Metals Subcategory (Option 4) 10-61
10-9C Pollutant-Level Long-term Averages, Variability Factors and Limitations
for Metal Finishing Job Shops Subcategory (Option 2) 10-62
10-9D Pollutant-Level Long-term Averages, Variability Factors and Limitations
for Metal Finishing Job Shops Subcategory (Option 4) 10-63
10-9E Pollutant-Level Long-term Averages, Variability Factors and Limitations
for Non-Chromium Anodizing Subcategory (Option 2) 10-64
10-9F Pollutant-Level Long-term Averages, Variability Factors and Limitations
for Printed Wiring Boards (Option 2) 10-65
10-9G Pollutant-Level Long-term Averages, Variability Factors and Limitations
for Printed Wiring Boards (Option 4) 10-66
10-9H Pollutant-Level Long-term Averages, Variability Factors and Limitations
for Oily Wastes Subcategory (Option 6) 10-67
10-91 Pollutant-Level Long-term Averages, Variability Factors and Limitations
for Railroad Line Maintenance Subcategory (Option 10) 10-67
xv
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LIST OF TABLES (Continued)
Page
10-9J Pollutant-Level Long-term Averages, Variability Factors and Limitations
for Shipbuilding Dry Docks Subcategory (Option 10) 10-68
11-1 MP&M Total Estimated Annualized Costs at the Proposed Options for
Existing Sources 11-4
11-2 Components of Total Capital Investment 11-10
11-3 RSMeans Building Construction Historical Cost Indexes 11-13
11-4 Contract-Hauling Costs for Various Waste Types 11-13
11-5 Wastewater Treatment Technologies and Source Reduction and Recycling
Practices for Which EPA Developed Cost Modules 11-14
11-6 List of Unit Operations Feeding Each Treatment Unit or In-Process
Technology 11-15
11-7 Sedimentation and Oil Treatment Technologies Considered Treatment in
Place for Various Technology Options 11-21
11-8 MP&M Equipment Cost Equations 11-25
12-1 Summary of Annual Pollutant Loadings for MP&M Direct Dischargers by
Subcategory 12-8
12-2 Summary of Annual Pollutant Loadings for MP&M Indirect Dischargers by
Subcategory 12-9
12-3 Publicly Owned Treatment Works (POTW) Removal Percents For Each
MP&M Pollutants of Concern 12-10
12-4 Summary of Annual Pollutant Reductions for MP&M Direct Dischargers
by Subcategory 12-15
12-5 Summary of Annual Pollutant Reductions for MP&M Indirect Dischargers
by Subcategory 12-16
12-6 Top Pollutants Removed by Proposed Option for General Metals Direct
Dischargers 12-17
xvi
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LIST OF TABLES (Continued)
Page
12-7 Top Pollutants Removed by Proposed Option for Metal Finishing Job
Shops Direct Dischargers 12-19
12-8 Top Pollutants Removed by Proposed Option for Printed Wiring Board
Direct Dischargers 12-21
12-9 Top Pollutants Removed by Proposed Option for Steel Forming
and Finishing Direct Dischargers 12-22
12-10 Top Pollutants Removed by Proposed Option for Oily Wastes Direct
Dischargers 12-24
12-11 Top Pollutants Removed by Proposed Option for Railroad Line
Maintenance Direct Dischargers 12-25
12-12 Top Pollutants Removed by Proposed Option for Shipbuilding Dry Dock
Direct Dischargers 12-26
12-13 Top Pollutants Removed by Proposed Option for General Metals Indirect
Dischargers 12-27
12-14 Top Pollutants Removed by Proposed Option for Metal Finishing
Job Shops Indirect Dischargers 12-29
12-15 Top Pollutants Removed by Option 2 for Non-Chromium Anodizing
Indirect Dischargers 12-31
12-16 Top Pollutants Removed by Proposed Option for Printed Wiring Board
Indirect Dischargers 12-32
12-17 Top Pollutants Removed by Proposed Option for Steel Forming
and Finishing Indirect Dischargers 12-33
12-18 Top Pollutants Removed by Proposed Option for Oily Wastes Indirect
Dischargers 12-35
12-19 Top Pollutants Removed by Option 10 for Railroad Line Maintenance
Indirect Dischargers 12-36
12-20 Top Pollutants Removed by Option 10 for Shipbuilding Dry Dock
Indirect Dischargers 12-37
xvn
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LIST OF TABLES (Continued)
Page
13-1 Energy Usage by Option 13-1
13-2 Wastewater Treatment Sludge by Option 13-4
13-3 Waste Oil Removed by Option 13-6
14-1 Pounds of Pollutants Removed by the Proposed BPT Option for Direct
Dischargers by Subcategory 14-3
14-2 Annualized Costs and Economic Impacts of the Proposed BPT Option for
Direct Dischargers by Subcategory 14-4
14-3 BPT/BAT Effluent Limitations for the General Metals Subcategory 14-7
14-4 BPT/BAT Effluent Limitations for the Metal Finishing Job Shops
Subcategory 14-10
14-5 BPT/BAT Effluent Limitations for the Non-Chromium Anodizing
Subcategory 14-13
14-6 BPT/BAT Effluent Limitations for the Printed Wiring Board Subcategory . 14-15
14-7 Production Normalized Flows (PNF) for Steel Forming and Finishing .... 14-18
14-8 BPT/BAT Effluent Limitations for the Steel Forming and Finishing
Subcategory 14-21
14-9 BPT/BAT Effluent Limitations for the Oily Wastes Subcategory 14-27
14-10 BPT Effluent Limitations for the Railroad Line Maintenance Subcategory . 14-29
14-11 BPT Effluent Limitations for the Shipbuilding Dry Dock Subcategory .... 14-30
14-12 Annual Pounds of Pollutants Removed by the Proposed PSES Option for
Indirect Dischargers by Subcategory 14-39
14-13 Annual Costs and Economic Impacts of the Proposed PSES Option for
Indirect Dischargers by Subcategory 14-40
14-14 PSES for the General Metals Subcategory 14-43
14-15 PSES for the Metal Finishing Job Shops Subcategory 14-47
xvin
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LIST OF TABLES (Continued)
Page
14-16 PSES for the Printed Wiring Board Subcategory 14-50
14-17 PSES for the Steel Forming and Finishing Subcategory 14-53
14-18 PSES for the Oily Wastes Subcategory 14-60
14-19 NSPS for the General Metals Subcategory 14-63
14-20 NSPS for the Metal Finishing Job Shops Subcategory 14-65
14-21 NSPS for the Non-Chromium Anodizing Subcategory 14-67
14-22 NSPS for the Printed Wiring Board Subcategory 14-68
14-23 NSPS for the Steel Forming and Finishing Subcategory 14-70
14-24 PSNS for the General Metals Subcategory 14-77
14-25 PSNS for Metal Finishing Job Shops Subcategory 14-78
14-26 PSNS for the Printed Wiring Board Subcategory 14-80
14-27 PSNS for the Steel Forming and Finishing Subcategory 14-81
15-1 (a) Descriptive Statistics of MP&M Survey Data for Unit Operations with
Square Feet as the Production-Normalizing Parameter 15-68
15-1 (b) Descriptive Statistics of MP&M Survey Data for Unit Operations with
Pounds of Metal Removed as the Production-Normalizing Parameter 15-73
15-2 Water Conservation Methods for Surface Treatment Rinses 15-74
15-3 Definitions of Pollution Prevention and Water Conservation Practices and
Technologies 15-76
15-4 Factors Affecting Drag-Out 15-81
15-5 Rinse-water Required for Various Plating Processes Based on Literature
Values 15-82
15-6 Adjusted Production-Normalized Flow (PNF) Data for Countercurrent
Cascade-Rinses 15-87
xix
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LIST OF TABLES (Continued)
Page
15-7 Pollution Prevention and Water Conservation Methods Applicable to
Machining Operations 15-88
15-8 Pollution Prevention and Water Conservation Methods Applicable to
Painting Operations 15-90
15-9 Pollution Prevention and Water Conservation Methods Applicable to
Cleaning Operations 15-91
xx
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LIST OF FIGURES
Page
3-1 Percentage of 1989 and 1996 MP&M Surveys Returned and Percentage of
Survey Respondents Engaged in MP&M Unit Operations 3-5
3-2 Number of MP&M Sites Visited and Sampled by Industrial Sector 3-27
4-1 MP&M Wastewater-Discharging Sites by Number of Employees and
Estimated Total Discharge Flow 4-2
4-2 Estimated Number of MP&M Facilities by EPA Region 4-3
4-3 MP&M Wastewater-Discharging Sites and Total Discharge Flow by
Activity 4-5
4-4 MP&M Wastewater-Discharging Sites and Total Discharge Flow by
Discharge Status 4-6
4-5 MP&M Wastewater-Discharging Sites by Total Discharge Flow 4-7
4-6 Number of Screener Survey Respondents Utilizing Each Zero Discharge
Method 4-9
4-7 Number of MP&M Wastewater-Discharging Sites by Number of Metal
Types Processed 4-31
6-1 Percentage of Wastewater-Discharging Facilities by Decade Built 6-10
8-1 Countercurrent Cascade Rinsing 8-2
8-2 Machine Coolant Recycling System 8-9
8-3 Centrifugation and Recycling of Painting Water Curtains 8-10
8-4 Electrodialysis Cell 8-11
8-5 Membrane Filtration Unit 8-14
8-6 Ion Exchange 8-15
8-7 Chemical Reduction of Hexavalent Chromium 8-21
8-8 Cyanide Destruction Through Alkaline Chlorination 8-23
xxi
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LIST OF FIGURES (Continued)
Page
8-9 Chemical Reduction / Precipitation of Chelated Metals 8-25
8-10 Continuous Chemical Emulsion Breaking Unit with Coalescing Plates 8-27
8-1 la Disc Oil Skimming Unit 8-29
8-1 Ib Belt Oil Skimming Unit 8-30
8-12 Dissolved Air Flotation Unit 8-32
8-13 Continuous Chemical Precipitation System with Lamella Clarifier 8-35
8-14 Effect of pH on Hydroxide and Sulfide Precipitation 8-36
8-15 Clarifier 8-39
8-16 Multimedia Filtration System 8-42
8-17 Gravity Thickening 8-44
8-18 Plate-and-Frame Filter Press 8-45
8-19 Rotary Vacuum Filter 8-46
9-1 End-of-Pipe Treatment Train for Options 1 and 2 Considered for the
Following Subcategories: General Metals, Metal Finishing Job Shops, Non-
Chromium Anodizing, Printed Wiring Boards, and Steel Forming and
Finishing 9-21
9-2 In-Process Water Use Reduction Technologies for Options 2 and 4
Considered for the Following Subcategories: General Metals, Metal
Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Boards,
and Steel Forming and Finishing 9-22
9-3 End-of-Pipe Treatment Train for Options 3 and 4 Considered for the
Following Subcategories: General Metals, Metal Finishing Job Shops, Non-
Chromium Anodizing, Printed Wiring Boards, and Steel Forming and
Finishing 9-23
9-4 End-of-Pipe Treatment Train for Options 5 and 6 Considered for the Oily
Wastes Subcategory 9-24
xxn
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LIST OF FIGURES (Continued)
Page
9-5 End-of-Pipe Treatment Train for Option 7 and 8 Considered for the
Following Subcategories: Oily Wastes, Railroad Line Maintenance,
Shipbuilding Dry Dock 9-25
9-6 End-of-Pipe Treatment Train for Options 9 and 10 Considered for the
Railroad Line Maintenance and Shipbuilding Dry Dock Subcategories 9-26
10-1 Summary of Technology Performance Data-Editing Procedures 10-5
10-2 Modified Delta-Lognormal Model 10-15
11-1 Relationship Between In-Process and End-of-Pipe Technologies and
Practices 11-43
11-2 Components of Total Capital Investment 11-44
11-3 Logic Used to Apply End-of-Pipe Technologies and Practices for the
Following Subcategories: General Metals, Metal Finishing Job Shops,
Non-Chromium Anodizing, Printed Wiring Board, and Steel Forming and
Finishing 11-45
11-4 Logic Used to Apply End-of-Pipe Technologies and Practices for the
Following Subcategories: Oily Waste, Railroad Line Maintenance, and
Shipbuilding Dry Dock 11-46
12-1 Estimates of MP&M Pollutant Loadings and Reductions 12-2
15-1 MP&M Permitting Process Flow Chart 15-8
15-2a Single Rinse Tank 15-35
15-2b Single Rinse Tank with Flow Reduction 15-35
15-2c Multiple Rinse Tanks with Flow Reduction 15-36
15-2d Countercurrent Rinsing with Flow Reduction 15-36
15-2e Multiple Rinse Tanks with Flow Reduction and Drag-Out Recovery 15-37
15-2f Multiple Rinse Tanks with Water Recycle, Drag-Out Recovery, and Metal
Recovery 15-37
xxin
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1.0 - Summary and Scope of the Regulation
i.o SUMMARY AND SCOPE OF THE REGULATION
Pursuant to the Clean Water Act (CWA), EPA is proposing effluent limitations
guidelines and standards for the Metal Products and Machinery (MP&M) Point Source Category.
This document and the administrative record for this rulemaking provide the technical basis for
these effluent limitations guidelines and pretreatment standards. Direct discharging facilities
discharge wastewater to a surface water (e.g., lake, river, ocean). Indirect discharging facilities
discharge wastewater to a publicly owned treatment works (POTW).
Section 1.1 presents an overview of the MP&M Point Source Category. Section
1.2 describes the applicability of the MP&M proposal and how it overlaps with previously
promulgated metals regulations. Section 1.3 summarizes the proposed effluent limitations
guidelines and standards.
1.1 Overview of the MP&M Point Source Category
The MP&M Point Source Category includes sites that generate wastewater as a
result of processing metal parts, metal products, and machinery. Although facilities in the MP&M
industry produce a wide range of products, the operations performed can be described by two
types of activities: manufacturing, and rebuilding/maintenance. Manufacturing is the series of unit
operations necessary to produce metal products, and is generally performed in a production
environment. Rebuilding/maintenance is the series of unit operations necessary to disassemble
used metal products into components, replace the components or subassemblies or restore them to
original function, and reassemble the metal product. These operations are intended to keep metal
products in operating condition and can be performed in either a production or a non-production
environment. These manufacturing and rebuilding/maintenance activities occur in industrial
sectors including:
• Aerospace;
Aircraft;
Bus and Truck;
• Electronic Equipment;
• Hardware;
Household Equipment;
Instruments;
• Job Shops;
• Mobile Industrial Equipment;
• Motor Vehicle;
• Office Machine;
• Ordnance;
• Precious Metals and Jewelry;
• Printed Wiring Boards;
Railroad;
• Ships and Boats;
• Stationary Industrial Equipment; and
1-1
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1.0 - Summary and Scope of the Regulation
• Miscellaneous Metal Products.
EPA has identified these 18 industrial sectors in the MP&M category; these sectors
manufacture, maintain and rebuild metal products under more than 200 different SIC codes. EPA
does not intend to include maintenance or repair of metal parts, products, or machines that occur
only as ancillary activities at facilities that it did not include in the 18 industrial sectors. EPA
believes that these ancillary repair and maintenance activities would typically generate only small
quantities of wastewater. As an example, EPA does not intend for the MP&M proposal to include
process wastewater discharges from an on-site machine or maintenance shop at a facility engaged
in the manufacture of organic chemicals when the facility operates that shop to maintain the
equipment related to manufacturing their products (i.e., organic chemicals). Alternatively, since
aircraft is an industrial sector that the Agency considered in developing the MP&M proposal, EPA
is proposing to include process wastewater discharges from activities related to maintaining or
repairing aircraft or other related (metal) equipment (e.g., deicing vehicles) at airports. EPA also
intends to cover wastewater from MP&M operations related to maintenance and repair of metal
products, parts, and machinery at military installations.
The MP&M industry includes almost 90,000 sites, of which an estimated 63,000
discharge process wastewater. Of the facilities discharging process wastewater, EPA estimates
that 93 percent are indirect dischargers and 7 percent are direct dischargers. The Agency
estimates that there are approximately 26,000 facilities that fall into one of three categories: zero
discharge, non-water-using, or contract haulers.
MP&M sites perform a wide variety of process unit operations on metal parts, products or
machines. In general, MP&M unit operations can be characterized as belonging to one of the
following types of unit operations:
• Assembly/disassembly operations;
• Metal deposition operations;
Metal shaping operations;
Organic deposition operations;
• Printed wiring board operations;
• Surface finishing operations;
Surface preparation operations; and
Dry dock operations.
At a given MP&M site, the specific unit operations performed, and the sequence of
those operations, depend on many factors, including the activity (i.e., manufacturing, rebuilding, or
maintenance), industrial sector, and type of product processed. The extent to which a facility uses
process water for these unit operations may vary from site to site.
EPA estimates that MP&M sites discharge approximately 120 billion gallons of
process wastewater per year. This wastewater typically contains metal pollutants (e.g., cadmium,
copper, chromium, iron, nickel, zinc) and total suspended solids. MP&M wastewater may also
contain oil and grease, cyanide, hexavalent chromium, and organic pollutants.
1-2
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1.0 - Summary and Scope of the Regulation
EPA identified several in-process pollution prevention, recycling, and end-of-pipe
treatment technologies and practices to control the discharge of pollutants from MP&M facilities.
Section 8.0 presents a more comprehensive discussion of standard in-process pollution
prevention, recycling, and end-of-pipe treatment technologies and practices and Section 9.0
describes the technology options that EPA analyzed for the proposed rule.
EPA estimated engineering compliance costs for each of the technology options for
a set of statistically selected model sites, and then used these sites to estimate compliance costs for
the entire MP&M industry. The Agency also estimated pollutant loadings and removals associated
with each of the technology options. EPA used the loadings and removals to assess the
effectiveness of each technology option. The Agency used the costs to estimate the financial
impact on the industry of implementing the various options, including the number of potential
facility closures, potential job losses and gains, and the ability of the site to finance the pollution
controls (see "Economic, Environmental, and Benefits Analysis of the Proposed Metal Products &
Machinery Rule" [EPA-821-B-008].) Details on the cost-effectiveness analysis can be found in
the document "Cost-Effectiveness Analysis of the Proposed Effluent Limitations Guidelines and
Standards for the Metal Products & Machinery Point Source Category." [EPA-821-B-00-007]
1.2 Applicability of MP&M and Overlap with Other Effluent Guidelines
EPA has previously established effluent limitations guidelines and standards for 13 industries that
may perform unit operations or process parts that are sometimes found at MP&M sites. These
effluent guidelines are:
Electroplating (40 CFR Part 413);
Iron & Steel Manufacturing (40 CFR Part 420);
Nonferrous Metal s Manufacturing (40 CFR Part 421);
Ferroalloy Manufacturing (40 CFR Part 424);
Metal Finishing (40 CFR Part 433);
Battery Manufacturing (40 CFR Part 461);
Metal Molding & Casting (40 CFR Part 464);
Coil Coating (40 CFR Part 465);
Porcelain Enameling (40 CFR Part 466);
Aluminum Forming (40 CFR Part 467);
Copper Forming (40 CFR Part 468);
Electrical & Electronic Components (40 CFR Part 469); and
Nonferrous Metals Forming & Metal Powders (40 CFR Part 471).
In 1986, the Agency reviewed coverage of these regulations and identified a
significant number of metals processing facilities discharging wastewater that these 13 regulations
did not cover. Based on this review, EPA performed a more detailed analysis of these unregulated
sites and identified the discharge of significant amounts of pollutants. This analysis resulted in the
decision to develop national limitations and standards for the "Metal Products and Machinery"
(MP&M) point source category. In general, when unit operations and their associated wastewater
discharges are already covered by an existing effluent guideline, they will remain covered under
that effluent guideline. However, EPA is proposing to replace the existing Electroplating (40 CFR
1-3
-------
1.0 - Summary and Scope of the Regulation
413) and Metal Finishing (40 CFR 433) effluent guidelines with the MP&M regulations for all
facilities in the Printed Wiring Board Subcategory and the Metal Finishing Job Shops Subcategory
(see Section 6.0 for a discussion on subcategorization). When a facility covered by existing
metals effluent guidelines (other than Electroplating or Metal Finishing) discharges wastewater
from unit operations not covered under those existing metals guidelines but covered under MP&M,
the facility will need to comply with both regulations.
EPA has determined that some processes regulated under the 1982 Iron and Steel
Category would be more appropriately regulated under the MP&M Category. The Agency
proposes to include the following steel finishing operations in the MP&M Category: cold forming
and surface finishing (e.g., electroplating) of steel bar, rod, wire, pipe, or tube; hot-dip coating of
steel (except for hot dip coating of steel sheets, strips, or plates); and drawing and coating of steel
wire. The Agency has determined that these operations are more similar to operations performed
at MP&M facilities than to operations performed at iron and steel manufacturing facilities. This
proposed regulation is not covering any hot forming operations or cold forming and surface
finishing operations on steel sheets, strips or plates. Such operations on steel sheets, strips, or
plates will remain regulated under the Iron and Steel Point Source Category (40CFR 420). If a
facility discharges wastewater from operations covered under both the Iron and Steel guideline
and the MP&M guideline, the facility will need to comply with both regulations.
Subcategory.
Table 1-1 below summarizes the coverage of industrial operations by each MP&M
Table 1-1
Clarification of Coverage by MP&M Subcategory
Subcategory
Proposing to continue to
cover under 40 CFR
Part 413
(Electroplating)
Proposing to continue to
cover under 40 CFR
Part 433
(Metal Finishing)
Proposing to cover
under 40 CFR Part 438
(Metal Products &
Machinery)
General Metals
Existing facilities that are
currently covered by 413
AND are indirect
dischargers that introduce
less than or equal to 1
million gallons per year
into a POTW.
Existing facilities that are
currently covered (or new
facilities that would be
covered) by 433 AND are
indirect dischargers that
introduce less than or equal
to 1 million gallons per
vear into a POTW.
All new and existing direct
dischargers in this
Subcategory regardless of
annual wastewater
discharge volume and all
new and existing indirect
dischargers in this
Subcategory with annual
wastewater discharges
greater that 1 million
gallons per year. (See
438.10)
1-4
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1.0 - Summary and Scope of the Regulation
Table 1-1 (Continued)
Subcategory
Metal Finishing
Job Shops
Non-Chromium
Anodizers
Note: Facilities
that perform
anodizing with
chromium or with
the use of
dichromate
sealants (or
commingle their
non-chromium
anodizing process
wastewater with
wastewater from
other MP&M
subcategories)
will be covered by
40CFR 438.
Printed Wiring
Board
(Printed Circuit
Board)
Steel Forming &
Finishing
Proposing to continue to
cover under 40 CFR
Part 413
(Electroplating)
None (see non-chromium
anodizing)
Existing indirect
dischargers that are
currently covered by 413
AND that only perform
non-chromium anodizing
(or do not commingle their
non-chromium anodizing
wastewater with other
process wastewater for
discharge).
None
N/A
Proposing to continue to
cover under 40 CFR
Part 433
(Metal Finishing)
None (see non-chromium
anodizing)
New and existing indirect
dischargers (not covered by
413) that only perform
non-chromium anodizing
(or do not commingle their
non-chromium anodizing
wastewater with other
process wastewater for
discharge).
None
N/A
Proposing to cover
under 40 CFR Part 438
(Metal Products &
Machinery)
All new and existing direct
and indirect discharges
under this subcategory.
These facilities would no
longer be covered by 413
or 433. (See 438.20)
Existing and new direct
dischargers that only
perform non-chromium
anodizing (or do not
commingle their non-
chromium anodizing
wastewater with other
process wastewater for
discharge). (See 438.30)
All new and existing direct
and indirect discharges
under this subcategory.
These facilities would no
longer be covered by 413
or 433. (See 438.40)
All new and existing direct
and indirect discharges
under this subcategory as
described. (See 438.50)
1-5
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1.0 - Summary and Scope of the Regulation
Table 1-1 (Continued)
Subcategory
Oily Wastes
Railroad Line
Maintenance
Shipbuilding Dry
Docks
Proposing to continue to
cover under 40 CFR
Part 413
(Electroplating)
N/A
N/A
N/A
Proposing to continue to
cover under 40 CFR
Part 433
(Metal Finishing)
N/A
N/A
N/A
Proposing to cover
under 40 CFR Part 438
(Metal Products &
Machinery)
All new and existing direct
and indirect dischargers
under this subcategory as
described. (See 438.60).
(This subcategory excludes
new and existing indirect
dischargers that introduce
less than or equal to 2
MGY into a POTW.
Facilities under the cutoff
are not and will not be
covered by national
categorical regulations).
All new and existing direct
dischargers under this
subcategory as described.
(See 438.70) There are no
national categorical
pretreatment standards for
these facilities.
All new and existing direct
dischargers under this
subcategory as described.
(See 438.80) There are no
national categorical
pretreatment standards for
these facilities.
N/A: Not applicable.
1.3 Proposed Effluent Limitations Guidelines and Standards
The MP&M effluent guidelines apply to process wastewater discharges from
existing or new industrial sites engaged in manufacturing, rebuilding, or maintenance of metal
parts, products or machines to be used in one of the industrial sectors listed in Section 1.1. The
effluent guidelines only cover process wastewater generated at MP&M facilities. EPA is not
covering non-process wastewater which includes sanitary wastewater, non-contact cooling water,
and stormwater.
1-6
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following:
1.0 - Summary and Scope of the Regulation
Typical unit operations at MP&M facilities include any one or more of the
Table 1-2
Typical Unit Operations Performed at MP&M Sites
Unit Operation Name
1. Abrasive Blasting
2. Abrasive Jet Machining
3. Acid Treatment with Chromium
4. Acid Treatment without Chromium
5. Alkaline Cleaning for Oil Removal
6. Alkaline Treatment with Cyanide
7. Alkaline Treatment without Cyanide
8. Anodizing with Chromium
9. Anodizing without Chromium
10. Aqueous Degreasing
11. Assembly/Disassembly
12. Barrel Finishing
13. Burnishing
14. Chemical Conversion Coating without
Chromium
15. Chemical Milling
16. Chromate Conversion Coating
17. Corrosion Preventive Coating
18. Electrical Discharge Machining
19. Electrochemical Machining
20. Electroless Plating
21. Electrolytic Cleaning
22. Electroplating with Chromium
23. Electroplating with Cyanide
24. Electroplating without Chromium or
Cyanide
25. Electropolishing
26. Floor Cleaning
27. Grinding
28. Heat Treating
29. Impact Deformation
30. Machining
31. Metal Spraying
32. Painting - Spray or Brush
33. Painting - Immersion
34. Plasma Arc Machining
35. Polishing
36. Pressure Deformation
3 7. Salt Bath Descaling
38. Soldering/Brazing
39. Solvent Degreasing
40. Stripping (paint)
41. Stripping (metallic coating)
42. Testing
43. Thermal Cutting
44. Washing Finished Products
45. Welding
46. Wet Air Pollution Control
Source: MP&M survey database.
Numerous sub-operations within those listed above are also included. Many of
these operations frequently have associated rinses that remove materials that preceding processes
deposit on the surface of the workpiece and water-discharging air pollution control devices which
become contaminated with process contaminants removed from the air. EPA is including both of
these wastewater flows under the scope of the regulation.
The Agency is also including wastewater discharges from non-contact,
nondestructive testing performed at MP&M facilities. EPA is not covering wastewater generated
from electroplating-type operations during semiconductor wafer manufacturing or wafer
fabrication processes occurring in a "clean room" environment because it believes that these
operations are much different than the other electroplating operations that EPA is covering by these
guidelines and do not contribute significant amounts of pollutants to the wastewater discharge.
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1.0 - Summary and Scope of the Regulation
EPA is proposing to cover wastewater generated from washing vehicles only when it occurs as a
preparatory step prior to performing an MP&M unit operation (e.g., prior to disassembly to
perform engine maintenance or rebuilding). EPA is also proposing to cover wastewater generated
from unit operations performed by drum reconditioners/refurbishers to prepare drums for reuse.
EPA did not collect information with respect to MP&M operations at gasoline service stations,
passenger car rental facilities, or utility trailer and recreational vehicle rental facilities; therefore,
this proposed regulation does not cover process wastewater generated by maintenance and repair
activities when they occur at gasoline stations or car rental facilities.
EPA is proposing to exclude facilities in the General Metals and Oily Wastes
Subcategories that discharge MP&M process wastewater below a specified flow rate (one and
two million gallons per year, respectively). The Agency expects that many facilities that only
perform repair and maintenance activities (e.g., auto repair shops, light aircraft maintenance) will
be excluded as most will fit into the applicability of the either the General Metals or Oily Waste
Subcategories and have process wastewater discharges below the subcategory-specific flow
cutoffs. EPA is considering a higher flow cutoff (three million gallons per year) for the Oily
Wastes Subcategory for the final regulation, and it solicits comment on appropriate flow cutoff
levels for all Subcategories in the preamble.
EPA is proposing to cover MP&M process wastewater at mixed-use facilities (i.e.,
any municipal, private, U.S. military or federal facility which contains both industrial and
commercial/administrative buildings at which one or more industrial sites conduct MP&M
operations within the facility's boundaries). The Agency is not proposing to cover wastewater
from non-metal repair, maintenance or manufacturing operations at mixed use facilities such as
wastewater from residential housing, schools, churches, recreational parks, shopping centers, gas
stations, utility plants, and hospitals. Therefore, EPA is proposing to allow wastewater generated
at different sites within a mixed use facility to be considered as separate discharges for the
purpose of applying the appropriate low flow cutoff (when applicable).
EPA may divide a point source category (e.g., MP&M) into groupings called
"subcategories" to provide a method for addressing variations between products, raw materials,
processes, and other factors which result in distinctly different effluent characteristics. Regulation
of a category by using formal subcategories provides that each subcategory has a uniform set of
effluent limitations which take into account technological achievability and economic impacts
unique to that subcategory. One result of grouping similar facilities into subcategories is the
increased likelihood that the regulations are practicable, and it diminishes the need to address
variations between facilities through a variance process. The CWA requires EPA, in developing
effluent limitations guidelines and pretreatment standards, to consider a number of different
subcategorization factors. (See Section 6.0 for a list of the factors considered for the proposed
MP&M rule and a detailed discussion of subcategorization).
As a result of the subcategorization analysis, EPA identified 8 distinct
subcategories: General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Oily
Wastes, Printed Wiring Boards, Railroad Line Maintenance, Shipbuilding Dry Docks, and Steel
Forming and Finishing.
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1.0 - Summary and Scope of the Regulation
In the 1995 proposal, EPA proposed concentration-based limits for a portion of the
MP&M Point Source Category with the requirement that control authorities (e.g., POTWs)
implement them as mass-based limits. The Agency did not finalize that proposal and, instead, has
proposed this regulation covering the entire MP&M Point Source Category. EPA proposed
requiring this conversion to mass-based limits because the Agency believed that it was necessary
to ensure the use of water conservation and pollution prevention practices similar to those that
were part of EPA's selected option (60 FR 28230). EPA received comments on the
administrative burden on POTWs associated with implementation of mass-based limits, largely
due to the fact that most MP&M facilities do not collect production information on a
wastestream-by-wastestream basis. EPA is again proposing concentration-based limits (for all
but one subcategory-Steel Forming & Finishing); however, the Agency is no longer requiring
control authorities (e.g., POTWs) or permit writers to implement the limits on a mass basis.
Instead EPA authorizes control authorities and permit writers to decide when it is most
appropriate to implement mass-based limits. EPA believes that this approach will reduce
implementation burden on POTWs and will result in increased use of water conservation practices
at the facilities where POTWs and permit writers think it is most needed.
The proposed limitations are presented in Section 14.0 for each subcategory, and
Section 15.0 provides guidance to permit writers on the conversion of concentration-based limits
to mass-based limits.
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2.0 - Background
2.0 BACKGROUND
This section presents background information supporting the development of
effluent limitations guidelines and standards for the Metal Products and Machinery (MP&M) Point
Source Category. Section 2.1 presents the legal authority to regulate the MP&M industry. Section
2.2 discusses the Clean Water Act, Pollution Prevention Act, Regulatory Flexibility Act (as
amended by the Small Business Regulatory Enforcement Fairness Act of 1996), and prior
regulation of the MP&M industry.
2.1 Legal Authority
EPA is proposing this regulation under the authorities of Sections 301, 304, 306,
307, 308, 402 and 501 of the Clean Water Act, 33 U.S.C. Sections 1311, 1314, 1316, 1317,
1318, 1342 and 1361 and under authority of the Pollution Prevention Act of 1990 (PPA), 42
U.S.C. 13101 etseq.,PubL. 101-508, November 5, 1990.
2.2 Regulatory Background
2.2.1 Clean Water Act
Congress adopted the Clean Water Act (CWA) to "restore and maintain the
chemical, physical, and biological integrity of the nation's waters" (Section 101(a), 33
U.S.C. 125 l(a)). EPA accomplishes this goal in part by restricting the types and amounts of
pollutants discharged from various industrial, commercial, and public sources of wastewater.
Direct dischargers must comply with effluent limitations in National Pollutant Discharge
Elimination System ("NPDES") permits; indirect dischargers must comply with pretreatment
standards for pollutants which may pass through or interfere with POTW operations. EPA
establishes these limitations and standards by regulation for categories of industrial dischargers
and bases them on the degree of control that can be achieved using various levels of pollution
control technology. These guidelines and standards are summarized briefly below.
1. Best Practicable Control Technology Currently Available (BPT)
(Section 304(b)(l) of the CWA).
BPT effluent limitations guidelines are applicable to direct dischargers
(i.e., sites that discharge wastewater to surface water). BPT effluent
limitations guidelines are generally based on the average of the best existing
performance by facilities of various sizes, ages, unit processes or other
common characteristics within the category or subcategory for control of
conventional, priority, and non-conventional pollutants.
In establishing BPT effluent limitations guidelines, EPA first considers the
total cost of achieving effluent pollutant reductions in relation to the effluent
pollutant reduction benefits. The agency also considers the age of
equipment and facilities involved, the processes employed, process
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2.0 - Background
changes required, engineering aspects of the control technologies, non-
water quality environmental impacts (including energy requirements), and
other factors as the Agency deems appropriate. The Agency considers the
category- or subcategory-wide cost of applying the technology in relation to
the effluent pollutant reduction benefits. Where existing performance is
uniformly inadequate, EPA may require higher levels of control than
currently in place in an industrial category if the Agency determines that the
technology can be practically applied.
2. Best Available Technology Economically Achievable (BAT)
(Sections 304(b)(2)(B) of the CWA).
BAT effluent limitations guidelines are applicable to direct discharging
sites. In general, BAT effluent limitations guidelines represent the best
existing economically achievable performance of plants in the industrial
subcategory or category. The CWA establishes BAT as the principal
national means of controlling the direct discharge of priority pollutants and
nonconventional pollutants to waters of the United States. The factors
considered in assessing BAT include the cost of achieving BAT effluent
reductions, the age of equipment and facilities involved, the processes
employed, engineering aspects of the control technology, potential process
changes, non-water quality environmental impacts (including energy
requirements), and such factors as the Administrator deems appropriate.
The Agency retains considerable discretion in assigning the weight to be
accorded to these factors. An additional statutory factor considered in
setting BAT is economic achievability. Generally, EPA determines the
economic achievability on the basis of the total cost to the industrial
subcategory and the overall effect of the rule on the industry's financial
health. As with BPT, where existing performance is uniformly inadequate,
EPA may base BAT upon technology transferred from a different
subcategory within an industry or from another industrial category. In
addition, BAT may include process changes or internal controls, even when
these technologies are not common industry practice.
3. Best Conventional Pollutant Control Technology (BCD
(Section 304(b)(4) of the CWA).
The 1977 Act included Section 301(b)(2)(E), which established BCT for
discharges of conventional pollutants from existing industrial point sources.
BCT effluent limitations guidelines are applicable to direct discharging
sites. Section 304(a)(4) designated the following as conventional
pollutants: biochemical oxygen demand (BOD5), total suspended solids
(TSS), fecal coliform, pH, and any additional pollutants defined by the
Administrator as conventional. The Administrator designated oil and
grease as an additional conventional pollutant on July 30, 1979 (44 FR
44501).
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2.0 - Background
BCT is not an additional limitation, but replaces BAT for the control of
conventional pollutants. In addition to other factors specified in Section
304(b)(4)(B), the CWA requires that EPA establish BCT limitations after
consideration of a two- part "cost-reasonableness" test. EPA explained its
methodology for the development of BCT limitations in 1986 (51 FR
24974, July 9, 1986).
4. New Source Performance Standards (NSPS)
(Section 306 of the CWA).
NSPS are applicable to new direct discharging sites and are based on the
best available demonstrated treatment technology. New facilities have the
opportunity to install the best and most efficient production processes and
wastewater treatment technologies. As a result, NSPS should represent the
greatest degree of effluent reduction attainable through the application of the
best available demonstrated control technology for all pollutants (i.e.,
conventional, nonconventional, and priority pollutants). In establishing
NSPS, the CWA directs EPA to take into consideration the cost of
achieving the effluent pollutant reduction and any non-water quality
environmental impacts (including energy requirements).
5. Pretreatment Standards for Existing Sources (PSES)
(Section 307(b) of the CWA).
PSES are applicable to indirect discharging sites (i.e., sites that discharge
to a publicly owned treatment works (POTW)). The CWA requires PSES
for pollutants that pass through, interfere with, or are otherwise
incompatible with POTW treatment processes or sludge disposal methods.
The CWA specifies that pretreatment standards are to be technology-based
and analogous to the BAT effluent limitations guidelines.
The General Pretreatment Regulations, which set forth the framework for
implementing categorical pretreatment standards, are found at 40 CFR Part
403. Those regulations contain a definition of pass-through that addresses
local rather than national instances of pass-through and establish
pretreatment standards that apply to all non-domestic dischargers (52 FR
1586, January 14, 1987).
6. Pretreatment Standards for New Sources (PSNS)
(Section 307(b) of the CWA).
PSNS are applicable to new indirect discharging sites. Like PSES, PSNS
are designed to prevent the discharges of pollutants that pass through,
interfere with, or are otherwise incompatible with the operation of POTWs.
PSNS are to be issued at the same time as NSPS. New indirect dischargers
have the opportunity to incorporate into their plants the best available
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2.0 - Background
demonstrated technologies. The Agency considers the same factors in
promulgating PSNS that it considers in promulgating NSPS.
The following table summarizes these regulatory levels of control and the pollutants controlled.
Table 2-1
Summary of Regulatory Levels of Control
Type of Sites Regulated
Existing Direct Dischargers
New Direct Dischargers
Existing Indirect Dischargers
New Indirect Dischargers
Pollutants Regulated
Priority Toxic Pollutants
Nonconventional Pollutants
Conventional Pollutants
BPT
X
BPT
X
X
X
BAT
X
BAT
X
X
BCT
X
BCT
X
NSPS
X
NSPS
X
X
X
PSES
X
PSES
X
X
PSNS
X
PSNS
X
X
Source: Clean Water Act.
2.2.2
Section 304(m) Requirements
Section 304(m) of the Clean Water Act (33 U.S.C. 1314(m)), added by the Water
Quality Act of 1987, requires EPA to establish schedules for (1) reviewing and revising existing
effluent limitations guidelines and standards ("effluent guidelines"), and (2) promulgating new
effluent guidelines. On January 2, 1990, EPA published an Effluent Guidelines Plan (55 FR 80),
in which it established schedules for developing new and revised effluent guidelines for several
industrial categories. In this notice, the Agency identified the Metal Products and Machinery
(formerly referred to as Machinery Manufacturing and Rebuilding) Point Source Category as
requiring effluent guidelines, and identified an estimated schedule for regulatory action.
The Natural Resources Defense Council, Inc. (NRDC) and Public Citizen, Inc.
challenged the Effluent Guidelines Plan in a suit filed in U.S. District Court for the District of
Columbia (NRDC et al. v. Reillv. Civ. No. 89-2980). The plaintiffs charged that EPA's plan did
not meet the requirements of Section 304(m). A Consent Decree in this litigation was entered by
the Court on January 31, 1992. The terms of the Consent Decree are reflected in the Effluent
Guidelines Plan published on September 8, 1992 (57 FR 41000). As a result of this decree, EPA
established a plan to propose effluent guidelines for the MP&M Point Source Category. As
discussed further in Section 2.2.5, EPA initially divided the industry into two phases based on
industrial sector. The 1992 Effluent Guidelines Plan scheduled EPA to propose the MP&M Phase
I Category by November 1994, and take final action by May 1996. EPA filed a motion with the
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2.0 - Background
court on September 28, 1994, and the court granted an extension for proposal and promulgation of
the final regulation.
On May 30, 1995, EPA published the MP&M Phase I proposal (60 FR 28210).
EPA received a large number of public comments on the Phase I proposal requesting that the
Agency combine all MP&M industrial sectors into one effluent guideline (see Section 2.2.5).
Based on these comments and after negotiations with NRDC, EPA filed an unopposed motion in
the U.S. District Court for the District of Columbia to modify the Consent Decree to merge the two
phases of the MP&M effluent guideline and to modify the dates for proposal and final action (61
FR 35042; July 3,1996). The court approved the motion, and the modified dates for the combined
MP&M regulation are October 2000 for proposal and December 2002 for final action (62 FR
8726; February 26,1997).
2.2.3 Pollution Prevention Act
The Pollution Prevention Act of 1990 (42 U.S.C. 13101 et seq.. Pub.L. 101-508,
November 5, 1990), makes pollution prevention the national policy of the United States. This act
identifies an environmental management hierarchy in which pollution "should be prevented or
reduced whenever feasible; pollution that cannot be prevented or recycled should be reused in an
environmentally safe manner whenever feasible; pollution that cannot be prevented or recycled
should be treated in an environmentally safe manner whenever feasible; and disposal or release
into the environment should be employed only as a last resort..." (Sec. 6602; 42 U.S.C. 13103).
According to the Pollution Prevention Act, source reduction reduces the generation
and release of hazardous substances, pollutants, wastes, contaminants, or residuals at the source,
usually within a process. The term source reduction "includes equipment or technology
modifications, process or procedure modifications, reformulation or redesign of products,
substitution of raw materials, and improvements in housekeeping, maintenance, training, or
inventory control. The term source reduction does not include any practice which alters the
physical, chemical, or biological characteristics or the volume of a hazardous substance, pollutant,
or contaminant through a process or activity which itself is not integral to or necessary for the
production of a product or the providing of a service." In effect, source reduction means reducing
the amount of a pollutant that enters a waste stream or that is otherwise released into the
environment prior to out-of-process recycling, treatment, or disposal. The Pollution Prevention
Act directs the Agency to, among other things, "review regulations of the Agency prior and
subsequent to their proposal to determine their effect on source reduction" (Sec. 6604; 42 U.S.C.
13103).
2.2.4 Regulatory Flexibility Act (RFA) as Amended by the Small Business
Regulatory Enforcement Fairness Act of 1996 (SBREFA)
Under the Regulatory Flexibility Act (RFA) [5 U.S. C. 601 et seq.. as amended by
the Small Business Regulatory Enforcement Fairness Act (SBREFA)], EPA generally is required
to conduct a regulatory flexibility analysis describing the impact of a proposed rule on small
entities as part of the rulemaking. EPA conducted an initial regulatory flexibility analysis (IRFA)
that examines the impact of the proposed rule on small entities, along with regulatory alternatives
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2.0 - Background
that could reduce that impact. The IRFA is available for review in the MP&M Administrative
Record (as chapter 10 in the Economic, Environmental and Benefits Analysis). Under section
605(b) of the RFA, if EPA certifies that a rule will not have a significant economic impact on a
substantial number of small entities, EPA is not required to prepare a regulatory flexibility
analysis. A regulatory flexibility analysis addresses:
The need for, objectives of, and legal basis for a rule.
• A description of, and where feasible, an estimate of the number of small
entities to which a rule would apply.
• The projected reporting, recordkeeping, and other compliance requirements
of a rule, including an estimate of the classes of small entities that would be
subject to a rule and the types of professional skills necessary for
preparation of the report or record.
• An identification, where practicable, of all relevant federal rules that may
duplicate, overlap, or conflict with a rule.
• A description of any significant regulatory alternatives to a rule that
accomplish the stated objectives of applicable statutes and that minimize
any significant economic impact of a rule on small entities. Consistent with
the stated objectives of the CWA, the analysis discusses significant
alternatives such as:
Establishing differing compliance or reporting requirements or
timetables that take into account the resources available to small
entities.
Clarifying, consolidating, or simplifying of compliance and
reporting requirements under the rule for such small entities.
- Using performance rather than design standards.
Excluding from coverage of a rule, or any part thereof, such small
entities. Based on the regulatory flexibility analysis and other
factors, EPA considered an exclusion to eliminate disproportionate
impacts on small businesses, which reduced the number of small
businesses that would be affected by a rule.
Pursuant to the RFA as amended by SBREFA, EPA also conducted outreach to
small entities and convened a Small Business Advocacy Review Panel to obtain advice and
recommendations of representatives of the small entities that potentially would be subject to the
rule's requirements. The Panel comprised representatives from three federal agencies: EPA, the
Small Business Administration, and the Office of Management and Budget. The Panel reviewed
materials EPA prepared in connection with the IRFA, and collected the advice and
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2.0 - Background
recommendations of small entity representatives. For this proposed rule, the small entity
representatives included nine small MP&M facility owner/operators, one small municipality, and
the following six trade associations representing different sectors of the industry: National
Association of Metal Finishers (NAMF)/Association of Electroplaters and Surface Finishers
(AESF)/MP&M Coalition; the Association Connecting Electronics Industries (also known as IPC);
Porcelain Enamel Institute; American Association of Shortline Railroads (ASLRA); Electronics
Industry Association (EIA); and the American Wire Producers Association (AWPA). The Panel
provided background information and analysis to the small entity representatives and conducted
meetings with the representatives. The Panel asked the small entity representatives to submit
written comment on the MP&M rulemaking in relation to the elements of the IRFA. The Panel
carefully considered these comments when developing their recommendations. The Panel
prepared a report (available in the MP&M Administrative Record) that summarizes their outreach
to small entities and the comments submitted by the small entity representatives. The Panel's
report also presented their findings on issues related to the elements of an IRFA and
recommendations regarding the rulemaking.
2.2.5
Regulatory History of the Metals Industry
EPA has promulgated effluent limitations guidelines and standards for 13 metals
industries. These regulations cover metal manufacturing, metal forming, and component finishing,
as summarized below.
Table 2-2
Summary of Metals Industry Effluent Guidelines
Coverage Area
Metal and Metal Alloy
Manufacturing
Metal Forming
Component Finishing
Title
Iron and Steel Manufacturing"
Nonferrous Metals Manufacturing
Ferroalloy Manufacturing
Iron and Steel Manufacturing"
Metal Molding and Casting
Aluminum Forming
Copper Forming
Nonferrous Metals Forming and Metal Powders
Electroplating
Iron and Steel Manufacturing"
Metal Finishing
Battery Manufacturing
Coil Coating
Porcelain Enameling
Electrical and Electronic Component Manufacturing
CFR Reference
40 CFR 420
40 CFR 421
40 CFR 424
40 CFR 420
40 CFR 464
40 CFR 467
40 CFR 468
40 CFR 471
40 CFR 413
40 CFR 420
40 CFR 433
40 CFR 461
40 CFR 465
40 CFR 466
40 CFR 469
Source: Code of Federal Regulations, Part 40.
"The Iron and Steel Manufacturing category includes metal manufacturing, metal forming, and component
finishing.
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2.0 - Background
In 1986, the Agency reviewed coverage of these 13 regulations and identified a
significant number of metals processing facilities discharging wastewater that these regulations did
not cover. Based on this review, EPA performed a detailed analysis of these unregulated sites and
identified the discharge of significant amounts of pollutants. This analysis resulted in the
formation of the Machinery Manufacturing and Rebuilding (MM&R) Point Source Category. In
1989, the Agency published a Preliminary Data Summary (PDS) for the MM&R industry, which is
located in the MP&M Public Record. Based on information contained in the PDS, EPA divided
the MM&R category into two phases by major industrial groups or sectors. The Agency
announced its schedule for the development of effluent guidelines for two separate MM&R phases
in EPA's January 2, 1990 Effluent Guidelines Plan (55 FR 80). One of the primary reasons for
dividing the category into two phases was the large number of facilities (over 900,000) identified
in the PDS as potentially included in the MM&R Point Source Category. On May 7, 1992, EPA
changed the category name to Metal Products and Machinery (MP&M) to clarify the coverage of
the category (57 FR 19748). Many questionnaire respondents found the MM&R label confusing
and interpreted the category to apply only to machinery sites. The Agency believes that the
MP&M title more accurately describes the coverage of the category.
The MP&M Point Source Category includes sites that generate wastewater while
processing metal parts, metal products, and machinery. The category covers process wastewater
generated during manufacturing, assembly, rebuilding, repair, or maintenance of metal parts,
products or machines for use in the following industrial sectors:
• Aerospace;
• Aircraft;
Bus and Truck;
Electronic Equipment;
• Hardware;
• Household Equipment;
Instruments;
Job Shops;
• Mobile Industrial Equipment;
• Motor Vehicles;
• Office Machines;
Ordnance;
• Precious Metals and Jewelry;
• Printed Wiring Boards;
Railroad;
Ships and Boats;
• Stationary Industrial Equipment; and
• Miscellaneous Metal Products.
EPA proposed effluent limitations guidelines, pretreatment standards, and new
source performance standards for the seven MP&M Phase I industrial sectors on May 30, 1995
(60 FR 28210). These seven industrial sectors included aerospace, aircraft, electronic equipment,
hardware, mobile industrial equipment, ordnance, and stationary industrial equipment. EPA
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2.0 - Background
received over 4,000 pages of public comment on the Phase I proposal. One area where
commenters from all stakeholder groups (i.e, industry, environmental groups, regulators) were in
agreement was that EPA should not divide the industry into two separate regulations. Commenters
raised concerns regarding the regulation of similar facilities with different compliance schedules
and potentially different limitations solely based on whether they were in a Phase I or Phase II
MP&M industrial sector. Furthermore, many facilities performed work in multiple sectors. In
such cases, permit writers and control authorities (e.g., POTWs) would need to decide which
MP&M rule (Phase I or II) applied to a facility.
Based on these comments, EPA proposed merging the two phases into one rule (61
FR 35042; July 3, 1996). In 1997, EPA obtained approval from the U.S. District Court for the
District of Columbia to combine MP&M Phases I and II into a single regulation for the 18 MP&M
industrial sectors and to extend the effluent guidelines schedule (62 FR 8726; February 26, 1997).
Extension of the schedule allowed EPA to use POTW survey data to develop more precise
estimates of administrative burden and allowed more extensive stakeholder involvement for data
collection. Under the 304(m) decree as amended, the final action on the MP&M rule is to be taken
by December 2002.
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3.0 - Data Collection Activities
3.0
DATA COLLECTION ACTIVITIES
This section summarizes the Agency's data collection activities for the MP&M
rulemaking effort. Section 3.1 summarizes the 1989 and 1996 MP&M industry questionnaires
including their purpose, recipient selection process, types of information collected, and uses of
data, Sections 3.2 and 3.3 summarize the site visit and field sampling programs, respectively,
conducted at MP&M sites. Sections 3.4, 3.5, and 3.6 discuss other data sources.
3.1
Industry Questionnaires
EPA distributed two screener and six detailed questionnaires (surveys) as part of
the data collection effort for the MP&M Point Source Category. As discussed in Section 2.0, EPA
initially divided the MP&M Point Source Category into two phases by major industrial sectors.
The surveys distributed for the seven Phase I industrial sectors requested data reflecting 1989
operations, and the surveys distributed for the 11 Phase II industrial sectors requested data
reflecting 1996 operations. The table below lists the industry surveys and the distribution dates.
Sections 3.1.1 and 3.1.2 discuss these questionnaire efforts.
Distribution of the MP&M Industry Surveys
Type of Survey
Screener
Detailed
Survey Name
1989 Screener Survey
1996 Screener Survey
1996 Benefits Screener
1989 Detailed Survey
1996 Long Survey
1996 Short Survey
1996 Municipality Survey
1 996 POTW Survey
1996 Federal Survey
Distribution Date
8/90
12/96
10/98
1/91
6/97
9/97
6/97
11/97
4/98
3.1.1
The 1989 Industry Surveys
EPA distributed a screener and a detailed survey for the initial MP&M proposed
regulation to manufacturing, rebuilding, and/or maintenance facilities engaged in the following
seven industrial sectors:
• Aerospace;
• Aircraft;
• Electronic Equipment;
Hardware;
Mobile Industrial Equipment;
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3.0 - Data Collection Activities
• Ordnance; and
Stationary Industrial Equipment.
The survey instructions and appendices provide descriptions of the industrial
sectors. The 1989 screener and detailed surveys are discussed below. EPA fully describes the
recipient selection, stratification schemes, and the type and potential use of the information
requested in the Information Collection Request (ICR) for the 1989 screener and detailed metal
products and machinery industry surveys. The ICR can be found in the MP&M Administrative
Record.
3.1.1.1 1989 Screener Survey
In August and September 1990, EPA mailed 8,342 screener surveys [also referred
to as the Mini Data Collection Portfolio (MDCP)] to sites believed to be engaged in MP&M
manufacturing, rebuilding, or maintenance activities in one of the seven industrial sectors listed
above. Mailout of the screener was the preliminary step in an extensive data-gathering effort for
these seven MP&M sectors. The purpose of the screener was to identify sites to receive the more
detailed survey and to make a preliminary assessment of these seven MP&M sectors.
1989 Screener Recipient Selection and Distribution
The Agency sent the screener to randomly selected MP&M sites engaged in
manufacturing, rebuilding, or maintenance operations in the seven industrial sectors. EPA
identified potential recipients using Standard Industrial Classification (SIC) codes. To examine
trends and similarities in manufacturing across the MP&M industrial sectors, EPA also sent
screener surveys to some facilities performing manufacturing in the following eight industrial
sectors:
• Bus and Truck;
• Household Equipment;
Instruments;
• Motor Vehicles;
• Office Machines;
• Precious and Nonprecious Metals;
Railroad; and
Ships and Boats.
The Agency did not send the screener to sites whose SIC codes indicated that they were engaged in
only MP&M rebuilding or maintenance (not manufacturing) operations in the eight industrial
sectors.
The Agency identified more than 190 SIC codes applicable to the seven MP&M
sectors listed in Section 3.1.1. Within each sector, EPA identified between one and 40 SIC codes.
EPA calculated the number of sites to receive the screener within each SIC code by a coefficient
of variation (CV) minimization procedure, described in the Statistical Summary for the Metal
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3.0 - Data Collection Activities
Products & Machinery Industry Surveys. Based on the number of sites selected within each SIC
code, the Agency purchased a list of randomly selected names and addresses from the Dun &
Bradstreet database for each SIC code. This list included twice the number of sites specified by
the CV minimization procedure for each SIC code.
EPA deleted sites from the Dun & Bradstreet list for the following reasons: sites
had SIC codes that were inconsistent with company names; sites were corporate headquarters
without manufacturing, rebuilding, or maintenance operations; or sites had insufficient mailing
addresses. EPA then randomly selected 30 to 60 sites within each SIC code and assigned each
site a randomly selected identification number. EPA assigned each site identification number a
corresponding barcode to track the distribution and processing of the screeners.
EPA established a toll-free helpline from August through October of 1990 to assist
screener recipients in completing the survey. This helpline received approximately 900 calls from
screener recipients. Additional information about the screener mailing (e.g., a copy of the
screener, specific mailing and processing procedures, non-CBI screener responses, follow-up
letters, and notes from helpline telephone conversations) is discussed in the following sections and
is contained in the MP&M Public Record.
1989 Screener Mailout Results
EPA initially mailed 8,000 screener surveys in August 1990. Based on the number
of surveys returned undelivered, EPA mailed an additional 342 in September 1990. In addition,
EPA received 22 unsolicited responses to the survey. Of the 8,364 potential respondents to the
screener, including those who provided unsolicited responses, 7,846 received the screener.
Screeners for the remaining 518 were returned to EPA as undeliverable. EPA assumed these sites
to be out of business. Of the total potential respondents, 84 percent (6,981) returned the screener
to EPA. A blank copy of the screener form and nonconfidential portions of the completed
screeners are contained in the MP&M Public Record. Table 3-1 and Figure 3-1 summarize the
mailout results for the 1989 and 1996 survey efforts.
Information Collected
The Agency requested the following site-specific information in the 1989 screener:
• Name and address of facility;
Contact person;
• Parent company;
Sectors in which the site manufactures, rebuilds, or maintains machines or
metal components;
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Table 3-1
1989 and 1996 MP&M Survey Mailout Results
3.0 - Data Collection Activities
Survey Type
1989 Screener Survey
1989 Detailed Survey
1996 Screener Survey
1996 Benefits Screener
1996 Long Detailed Survey
1996 Short Detailed Survey
1996 Municipality Detailed Survey
1996 POTW Detailed Survey
1996 Federal Detailed Survey
Mailed
8,342
1,020
5,325
1750
353
101
150
150
-
Returned
Undelivered
518
0
579
155
1
1
3
2
-
Returned
(%)
6,98 la (84)
998b (98)
4248 (80)
1392 (80)
311(88)
83 (82)
135 (90)
147 (98)
51 (-)
Not
Returned
(%)
865(11)
22 (X)
497(10)
161 (10)
41 (12)
17(17)
12(8)
1(1)
-
Respondents Engaged
in MP&M Operations
(%)
3,598 (52)
792 (79)
2,424 (57)
1354 (97)
297 c (95)
75 (90)
71 (53)
144 (98)
44 (86)
Respondents Not
Engaged in MP&M
Operations
(%)
3,373 (48)
199 (20)
1,824 (12)
38(3)
8(3)
8(10)
64 (47)
3(2)
7(14)
includes 22 unsolicited responses.
bSeven of the 1989 detailed surveys were returned too late to be incorporated into the detailed survey database.
Includes long survey respondents that discharge <1 mgy.
~ Not applicable to the survey.
Source: 1989 and 1996 Survey Tracking Systems.
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3.0 - Data Collection Activities
w
1996 Federal Detailed
1 996 POTW Detailed
1996 Municipality Detailed
1996 Short Detailed
1996 Long Detailed
1996 Benefits Screener
1 996 Screener
1989 Detailed
1989 Screener
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percentage
d Surveys Returned
• Respondents Engaged in MP&M
Operations
f NA - The number of federal surveys distributed is not certain, and the percentage of returned surveys cannot be calculated.
Figure 3-1. Percentage of 1989 and 1996 MP&M Surveys Returned and
Percentage of Survey Respondents Engaged in MP&M Unit Operations
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3.0 - Data Collection Activities
SIC codes corresponding to products at the site;
• Number of employees;
• Annual revenues;
• Unit operations performed at the site;
Whether there is process water use and/or wastewater discharge for each
unit operation performed at the site; and
• Base metal(s) on which each unit operation is performed.
The Agency used a computerized database system to store and analyze data received from the
screeners. The database dictionary and all nonconfidential screener surveys are located in the
MP&M Public Record.
EPA determined the number of sites engaged in MP&M operations by responses to
the screener. As shown in Table 3-1, approximately 52 percent of the 1989 screener survey
respondents reported that their sites were engaged in MP&M operations and approximately 48
percent reported no MP&M operations at their sites. The status of 10 of the sites could not be
determined because they returned incomplete screeners and did not respond to follow-up efforts.
The Agency contacted a statistically representative sample of the nonrespondent
sites (i.e., sites that did not return the screener) and sites reporting "not engaged" in MP&M
operations to determine whether their responses were due to confusion over the scope of the
MP&M industry. Based on the results of this follow-up, EPA adjusted the survey weights for
misclassification and response. The methodology for calculating the adjustment factors is
provided in Chapter 4 of the Statistical Summary for the Metal Products and Machinery Industry
Surveys. Part I which is located in the MP&M Administrative Record.
1989 Screener Data Entry. Engineering Coding, and Analysis
EPA reviewed all of the screener surveys prior to data entry. As part of this effort,
the Agency reviewed all documentation provided by the site, corrected errors and deficiencies,
and coded the information for data entry. In some cases, these revisions required telephone
contact with site personnel. The Agency contacted more than 1,100 screener recipients to resolve
survey deficiencies and code information for data entry. Following preliminary review, EPA
entered the scannable data (i.e., responses to multiple-choice, Mark Sense™ questions) into the
database using a Scantron™ reader. EPA scanned each form twice and compared the information
using a computer program as a quality control (QC) check. The Agency performed double-key
entry of nonscannable data, resolved any inconsistencies, and converted the data to database files.
Based on the screener mailout results, EPA developed an MP&M industry profile
for the seven sectors. The screener database report provides estimates of the national population
for sites in these MP&M sectors with regard to water use characteristics, size, location, sector,
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3.0 - Data Collection Activities
unit operations, and metal types. The Statistical Summary for the Metal Products & Machinery
Industry Surveys discusses the sample size determination and statistical procedures for developing
national estimates for the industry.
3.1.1.2 1989 Detailed Survey
Based on responses to the 1989 screener, EPA sent a more detailed survey to a
select group of water-using MP&M sites. This survey, also referred to as the data collection
portfolio (DCP), was designed to collect detailed 1989 technical and financial information. EPA
used this information to characterize MP&M sites from the seven industrial sectors, develop
pollutant loadings and reductions, and develop compliance cost estimates, as discussed later in
this document.
EPA mailed 896 detailed surveys in January 1991. Based on the number of
detailed surveys returned undelivered, EPA mailed an additional 124 detailed surveys in January
and February 1991, for a total of 1,020 detailed surveys mailed. A blank copy of the 1989
detailed survey and copies of the nonconfidential portions of the completed detailed surveys are
located in the MP&M Public Record.
1989 Detailed Survey Recipient Selection and Distribution
EPA selected 1,020 detailed survey recipients from the following three groups of
sites:
• Water-discharging 1989 screener respondents (860 sites);
Water-using 1989 screener respondents that did not discharge process
water (74 sites); and
Water-discharging sites from key MP&M companies that did not receive the
1989 screener (86 sites).
The methods used to select sites within each group are described below.
The Agency mailed the 1989 detailed survey to all 860 water-discharging screener
respondents. EPA's intent in collecting detailed data from all 860 sites was to characterize the
potential variations in unit operations performed and water use practices among water-discharging
sites in these seven MP&M industrial sectors.
The Agency mailed the 1989 detailed survey to a probability sample of 50 screener
respondents that reported using but not discharging process water. EPA selected these sites to
provide information on water-use practices at sites that use but do not discharge process water,
and to determine if "zero-discharge" practices used at those sites could be used at other MP&M
sites. In addition to the 50 probability sample sites, EPA also mailed the 1989 detailed survey to
an additional 24 screener respondents that reported using but not discharging process water. The
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3.0 - Data Collection Activities
Agency selected these sites because they performed unit operations that were not expected to be
sufficiently characterized by detailed surveys mailed to other sites. The unit operations that EPA
expected at each of the 24 sites are listed in the MP&M Public Record.
EPA mailed the 1989 detailed survey to 86 sites that did not receive the 1989
screener. The Agency identified these sites to represent key companies in the MP&M industry that
EPA did not select as 1989 detailed survey recipients based on the screener mailout. EPA
identified key companies from Dun & Bradstreet company lists, the Thomas Register, Fortune
Magazine's list of the top 500 U.S. companies, and MP&M site visits at companies with annual
revenues of $50 million or more that EPA believed to be leading companies in their particular
MP&M sector. The Agency contacted each of the key companies to identify sites within the
company that were engaged in MP&M operations and used process water to perform MP&M
operations. Records of these follow-up telephone calls are located in the MP&M Public Record.
EPA did not use these 86 surveys for developing the national estimates because the Agency did not
randomly select these facilities.
EPA operated a toll-free telephone helpline from January until July 1991 to assist
recipients in completing the 1989 detailed survey. The helpline received approximately 1,400
calls from detailed survey recipients. Callers to the 1989 detailed survey helpline typically
requested the following:
Assistance with the technical sections of the detailed survey (e.g., technical
clarification of unit operation definitions);
Additional time to complete the survey;
• Assistance with the financial sections of the detailed survey (these calls
were referred to a separate economics helpline); or
Clarification of the applicability of the survey (i.e., did the survey apply to
the site?).
Records for nonconfidential telephone calls to the helpline and to EPA personnel are located in the
MP&M Public Record.
1989 Detailed Survey Mailout Results
Table 3-1, on page 3-4, summarizes the results of the detailed survey mailout. Of
the 1,020 sites that received the detailed survey, 998 responded to the survey and 22 did not. Of
the sites that responded, EPA did not include 199 sites in the detailed survey database for one of
the following reasons:
• The site was out of business;
The site did not use process water;
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3.0 - Data Collection Activities
The site was not engaged in MP&M operations; or
Process information at the site was Department of Defense or Department of
Energy classified information.
Specific reasons for not using data from these sites are located in the MP&M Public Record.
Upon review of the detailed surveys submitted by these sites, EPA determined 87
sites to be in the other 11 industrial sectors rather than the seven sectors identified in Section
3.1.1. Because the scope of the detailed survey mailout effort included only sites from the seven
industrial sectors listed in Section 3.1.1, EPA did not include these 87 sites in the detailed survey
database.
Information Collected
This section describes the information collected in each part of the 1989 detailed
survey and the reasons for collecting this information. The detailed survey instructions and the
Information Collection Request (ICR) for this project contain further details on the types of and
potential uses for information collected. These documents are located in the MP&M
Administrative Record.
The Agency designed the 1989 detailed survey to collect information necessary to
develop effluent guidelines and standards for the MP&M industry. EPA divided the detailed
survey into the following parts:
• Part I - General Information;
• Part II - Process Information;
Part III - Water Supply;
Part IV - Wastewater Treatment and Discharge;
• Part V - Process and Hazardous Wastes; and
• Part VI - Financial and Economic Information.
Part I (questions 1 through 13) requested information necessary to identify the site,
to characterize the site by certain variables, and to confirm that the site was engaged in MP&M
operations. This information included: site name, address, contact person, number of employees,
facility age, average energy usage, discharge permit status, and MP&M activity (manufacturing,
rebuilding, or maintenance).
Part II (questions 14 through 21) requested detailed information on MP&M
products, production levels, unit operations, activity, water use for unit operations, wastewater
discharge from unit operations, miscellaneous wastewater sources, waste minimization practices
(e.g., pollution prevention), and air pollution control for unit operations. EPA requested the site to
provide detailed technical information (e.g., water balance, chemical additives, metal type
processed, disposition of wastewater) for each MP&M unit operation and air pollution control
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3.0 - Data Collection Activities
device using process water. This section also requested information on unique and/or auxiliary
MP&M operations. EPA used this information to evaluate raw waste characteristics, water use
and discharge practices, and sources of pollutants for each MP&M unit operation.
Part III (question 22) requested information on the water supply for the site. EPA
requested the site to specify the source water origin, average intake flow, average intake operating
hours, and the percentage of water used for MP&M operations. EPA used this information to
evaluate overall water use for the site.
Part IV (questions 23 through 33) requested detailed information on MP&M
influent and effluent wastewater treatment streams and wastewater treatment operations. The
information requested included: the origin of each stream contributing to the site's overall
wastewater discharge; a block diagram of the wastewater treatment system; detailed technical
information (e.g., wastewater stream flow rates, treatment chemical additives, system capacity,
disposition of treatment sludge) for each wastewater treatment operation; self-monitoring data; and
capital and operating cost data. EPA collected this information to evaluate treatment in place at
MP&M sites, to develop and design a cost model and to assess the long-term variability of MP&M
effluent streams.
Part V (question 34) requested detailed information on the types, amounts, and
composition of wastewater and solid/hazardous wastes generated during production or waste
treatment, and the costs of solid waste disposal. EPA collected this information to evaluate the
types and amounts of wastes currently discharged, the amount of waste that is contract hauled off
site, and the cost of contract-hauling wastes.
Part VI requested detailed financial and economic information from the site and the
company owning the site. The Economic, Environmental, and Benefits Analysis document for the
proposed rule, which is located in the MP&M Administrative Record, presents information from
this part.
1989 Detailed Survey Review. Coding, and Data Entry
The Agency completed a detailed engineering review of the detailed surveys,
including coding responses to questions from Parts I through V of the detailed surveys to facilitate
entry of technical data into a database. The MP&M DCP Database Dictionary identifies all
database codes developed for this effort and the database dictionary for Section VI of the detailed
survey are located in the MP&M Administrative Record.
The Agency followed up with telephone calls to all respondents who: (1) did not
provide information on operations (manufacturing, rebuilding, or maintenance) or sectors; (2) did
not provide metal type or unit operation descriptions for each water-using unit operation; or (3)
did not provide descriptions for each wastewater treatment operation. EPA also made follow-up
calls to clarify incomplete or contradictory technical or economic information. EPA confirmed all
information obtained from follow-up calls by sending a letter to the site.
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3.0 - Data Collection Activities
EPA developed a database to store all technical data provided in the detailed
surveys. After engineering review and coding, the Agency entered data from the detailed surveys
into the database using a double key-entry and verification procedure. EPA coded and entered
data from 792 detailed survey respondents determined to be engaged in MP&M activities into the
detailed survey database. The MP&M DCP Database Dictionary presents the database structure
and defines each field in the detailed survey database and the codes that describe data in these
fields.
1989 Detailed Survey Data Analysis
The Statistical Summary for the Metal Products & Machinery Industry Surveys
provides estimates of the national population of MP&M water-discharging sites with regard to
size, location, sector, unit operations, metal types, discharge flows, and production-normalized
flows. The report discusses the statistical procedures for developing national estimates for the
industry, and is located in the MP&M Administrative Record.
3.1.2 The 1996 Industry Surveys
Between 1996 and 1998, EPA distributed one screener and five detailed surveys.
The five detailed surveys included the long, short, municipality, federal, and publicly owned
treatment works (POTW) surveys. The Agency distributed the 1996 surveys to commercial and
government (federal, state, and local) facilities that manufacture, rebuild, or maintain metal
products or parts to be used in one of the following 11 MP&M industrial sectors:
• Bus and Truck;
Household Equipment;
Instruments;
• Job Shops;
• Motor Vehicles;
• Office Machines;
Precious Metals and Jewelry;
• Printed Wire Boards;
• Railroad;
Ships and Boats; and
Miscellaneous Metal Products.
The job shop sector includes facilities that manufacture, rebuild, or maintain metal products or
parts but do not own 50 percent or more of the items they process. EPA distributed the POTW
detailed survey to POTWs to assess the impact of the MP&M regulation on permitting entities. The
1996 screener and detailed surveys are discussed below. Recipient selection, stratification
schemes, and the type and potential use of the information requested are described in more detail
in the ICR for the 1996 screener and detailed metal products machinery industry surveys which is
located in the MP&M Administrative Record.
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3.0 - Data Collection Activities
3.1.2.1 1996 Screener Surveys
In December 1996 and February 1997, EPA distributed 5,325 screener surveys to
sites believed to be engaged in MP&M manufacturing, rebuilding, or maintenance activities in one
of 11 MP&M industrial sectors listed above. The purpose of the screener surveys was to identify
sites to receive the more detailed survey and to make a preliminary assessment of the MP&M
industry for the 11 industrial sectors listed in Section 3.1.2. EPA sent an additional 1,750
screeners to facilities located in Ohio (a state with a high concentration of MP&M facilities) as
part of the benefits study. The Agency used these screeners to collect data to analyze
environmental benefits.
1996 Screener Recipient Selection and Distribution
As discussed above, EPA sent the 1996 screener survey to 5,325 randomly
selected MP&M sites (includes replacement sites). The Agency selected potential recipients from
the Dun & Bradstreet database based on the industrial sector (using the SIC code), activity (i.e.,
manufacturing, maintenance, or rebuilding), size as measured by number of employees, and
wastewater discharge flow rate.
The Agency identified more than 126 SIC codes applicable to the 11 MP&M
sectors. Within each sector, EPA identified between 1 and 26 SIC codes. EPA calculated the
number of sites to receive the 1996 screener within each SIC code by a coefficient of variation
(CV) minimization procedure described in the Statistical Summary for the Metal Products &
Machinery Industry Surveys. Based on the number of sites selected within each SIC code, the
Agency obtained a list of randomly selected names and addresses from Dun & Bradstreet. This
list included twice the number of sites specified by the CV minimization procedure for each SIC
code. EPA randomly selected the initial list of sites from the Dun & Bradstreet database for each
SIC code.
EPA reviewed the potential sites and deleted sites for the following reasons:
• The site was a corporate headquarters without manufacturing, rebuilding, or
maintenance operations;
The site received a 1989 screener or detailed survey;
• The site was a duplicate of a miscellaneous facility in the list of potential
MP&M sites.
• The site had an SIC code which was inconsistent with company name; or
The site had an insufficient mailing address.
EPA established a toll-free telephone helpline and an electronic mail address to
assist screener recipients in completing the survey. EPA received helpline calls and electronic
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3.0 - Data Collection Activities
mail inquiries from more than 600 screener recipients. Nonconfidential notes from helpline and
review follow-up calls are located in the MP&M Public Record.
1996 Screener Mailout Results
EPA initially mailed 4,900 surveys in December 1996. The Agency distributed an
additional 425 surveys to replace surveys that were returned undelivered. EPA assumed the
undeliverable sites to be out of business. Of the 5,325 surveys mailed, 80 percent (4,248) of the
recipients returned completed surveys to EPA. A blank copy of the 1996 screener and
nonconfidential portions of the completed screeners are located in the MP&M Public Record.
Table 3-1 and Figure 3-1, on pages 3-4 and 3-5, summarize the MP&M survey mailout results.
The Agency contacted a statistically representative sample of nonrespondent sites
to determine whether these sites were engaged in MP&M operations and discharged process
wastewater. Only 24 percent of the nonrespondents contacted were engaged in MP&M operations,
and approximately half of these facilities did not discharge process wastewater.
Information Collected
The Agency requested the following site-specific information in the screener:
Name and address of facility;
• Contact person;
Whether process water is used at the site;
• Destination of process wastewater discharged;
Volume of process wastewater discharged;
• Number of employees;
• Annual revenue;
• Sectors in which the site manufactures, rebuilds, or maintains machines or
metal components; and
• Unit operations performed at the site and whether there is water use and/or
wastewater discharge for each unit operation performed at the site.
The Agency used a computerized database system to store and analyze data
received from the 1996 screeners. Nonconfidential portions of the screener surveys and the
database dictionary are located in the MP&M Administrative Record.
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3.0 - Data Collection Activities
1996 Screener Data Review and Data Entry
EPA reviewed the 1996 screener survey for accuracy and consistency and
formatted the information for data entry. The Agency contacted approximately 1,800 screener
respondents to resolve deficient and inconsistent information prior to data entry. Following
review, EPA double key-entered and compared the data from the formatted screeners, using a
computer program, as a quality control check. The Agency then reviewed the database files for
deficiencies and inconsistencies, and resolved all issues for the final survey database.
1996 Benefits Screener Survey
For an environmental benefits study, EPA sent the 1996 screener survey to 1,750
(including replacement sites) randomly selected sites in Ohio, a state with a large number of
MP&M sites. EPA used the data for the environmental benefit analyses. The selection criteria
and sampling frame for the benefits screener recipients are described in more detail in memoranda
located in the MP&M Administrative Record.
The Agency initially mailed the benefits screener to 1,600 facilities in October
1998. EPA mailed an additional 150 facilities the screener in February 1999 to replace surveys
that were returned undelivered. The Agency assumed the undeliverable surveys to be out of
business. Of the 1,750 surveys mailed, 80 percent (1,392) of the recipients returned completed
screeners to EPA. A blank copy of the 1996 benefits screener and nonconfidential portions of the
completed benefits screeners are located in the MP&M Public Record. Table 3-1 and Figure 3-1,
on pages 3-4 and 3-5, summarize MP&M mailout results.
EPA established a toll-free telephone helpline and an electronic mail address to
assist screener recipients in completing the survey. EPA received helpline calls and electronic
mail inquiries from more than 900 benefits screener recipients. Nonconfidential notes from
helpline and review follow-up calls are located in the MP&M Public Record.
The Agency followed the same review, data entry, and database development
procedures used for the original 1996 screener survey. The benefits screener database is
discussed in the Economic. Environmental and Benefits Analysis of the Proposed Metal Products
& Machinery Rule. EPA contacted more than 400 screener respondents to resolve deficient and
inconsistent information prior to data entry.
3.1.2.2 1996 Long Detailed Survey
EPA distributed the long detailed surveys in June 1997 to 353 MP&M wastewater-
discharging industrial facilities. EPA designed this survey to gather detailed technical and
economic information required to develop the MP&M effluent limitations guidelines and
standards. The long survey is discussed below.
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3.0 - Data Collection Activities
1996 Long Survey Recipient Selection and Distribution
In June 1997, EPA sent the long survey to all 353 1996 screener respondents who
indicated they performed operations in one of the 11 MP&M industrial sectors listed in Section
3.1.2 and discharged one million or more gallons of MP&M process wastewater annually. EPA
established a toll-free telephone helpline and an electronic mail address to assist long survey
recipients in completing the survey. EPA received helpline calls and electronic mail inquiries
from approximately 200 long survey recipients. Nonconfidential notes from helpline and review
follow-up calls are located in the MP&M Public Record.
1996 Long Survey Mailout Results
Of the 353 surveys mailed, 88 percent (311) of the recipients returned completed
surveys to EPA. One survey was returned as undelivered and EPA assumed the facility to be out
of business. A blank copy of the 1996 long survey and nonconfidential portions of the completed
long surveys are located in the MP&M Public Record. Table 3-1 and Figure 3-1, on pages 3-4
and 3-5, summarize the MP&M survey mailout results.
Information Collected
This section describes the information collected in each section of the 1996 long
survey and the reason EPA collected the information. Further details on the types of information
collected and the potential uses of the information are contained in the ICR for this project and in
the survey instructions which are located in the MP&M Administrative Record.
EPA divided the long detailed survey into the following sections:
• Section I: General Site Information;
• Section II: General Process Information;
• Section III: Specific Process Information;
• Section IV: Economic Information; and
• Section V: Voluntary Supplemental Information.
Table 3-2 summarizes the information requested in the 1996 long, short, federal, and municipality
detailed surveys by question number. EPA designed the long, short, municipality, and federal
surveys to collect similar detailed process information from different audiences, as discussed
below for each survey.
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3.0 - Data Collection Activities
Table 3-2
Summary of 1996 Detailed Survey Information by Question Number
Survey Question Number
Long and
Federal
Section I
1
Section II
2-5
6,7
8,9
10
—
11
12
13
Section III
14-15
16
17-23
24-29
30
31-41
42
43-44
45
—
Section IV
1-9
Section V
1
2
3
2,4
5
Short
Section I
1
Section II
2-5
6,7
8,9
10
11-12
13
15
16
—
—
Section II
17
—
—
—
Section II
14
—
—
Section IV
1-8
Section V
1
2
3
2,4
5
Municipality
Part II
1
2-5
5,6
7,8
9
10-11
12
13
14
—
—
16
—
—
—
15
—
—
Parti
1-3
—
—
—
—
—
Type of Information Requested
Industrial sector activities
Site location and facility contact
Number of employees and age of site
Discharge status and destination
Permits under Miscellaneous categorical effluent guidelines
Types of end-of-pipe wastewater treatment units
Metal types processed
5 major products (quantity and sector)
Unit operations: water use and associated rinses
General water use and costs
Production process diagram
Detailed description of wet unit operations performed
In-process pollution prevention technologies or practices
Wastewater treatment (WWT) diagram
Detailed design and operating parameters of WWT units
WWT costs by treatment unit
Wastewater sampling and analysis conducted
Contract haul and disposal costs
Facility comments page
Financial and economic data
Parent firm name and contact, number of Miscellaneous MP&M
facilities
Number of employees for Miscellaneous facility(ies)
MP&M sector and activity
Discharge status and destination
Unit operations: water use and discharge status
— Question is not applicable to this survey.
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3.0 - Data Collection Activities
Section I requested information to determine if the facility was engaged in MP&M
operations. Question 1 requested the site to identify the MP&M industrial sector and type of
activity (manufacturing, rebuilding, or maintenance) performed.
Section II requested information to identify the site location and contact person,
number of employees, facility age, process wastewater discharge status and destination, and
wastewater discharge permits and permitting authority. This section also requested general
information about metal types processed, MP&M products and production levels, water use for
unit operations, and wastewater discharge from unit operations. EPA used the process information
to evaluate water use and discharge practices, and sources of pollutants for each MP&M unit
operation.
Section III requested detailed information on MP&M wet unit operations, pollution
prevention practices, wastewater treatment technologies, costs for water use and wastewater
treatment systems, and wastewater/sludge disposal costs. EPA also requested the site to provide
block diagrams of the production process and the wastewater treatment system. The unit operation
information requested included: metal types processed, production rate, operating schedule,
chemical additives, volume and destination of process wastewater and rinse waters, in-process
pollution prevention technologies, and in-process flow control technologies. The information
requested for each wastewater treatment unit included: operating flow rate, design capacity,
operating time, chemical additives, and unit operations discharging to each treatment unit. In
addition, EPA requested the site to provide the type of MP&M wastewater sampling data
collected. EPA used these data to characterize the industry, to perform subcategorization analyses,
to identify best management practices, to evaluate performance of the treatment technology for
inclusion in the regulatory options, and to develop regulatory compliance cost estimates.
Section IV requested detailed financial and economic information about the site or
the company owning the site. Information from this section is presented in the Economic.
Environmental, and Benefits Analysis of the Proposed Metal Products & Machinery Rule, which is
located in the MP&M Administrative Record.
Section V requested supplemental information on Miscellaneous MP&M facilities
owned by the company. EPA included this voluntary section to measure the combined impact of
proposed MP&M effluent guidelines on companies with multiple MP&M facilities that discharge
process wastewater. This section requested the same information collected in the 1996 MP&M
screener survey. Responses to questions in this section provided the size, industrial sector,
revenue, unit operations, and water usage of the company's Miscellaneous MP&M facilities.
1996 Long Survey Data Review and Data Entry
EPA completed a detailed engineering review of Sections I through III of the
detailed survey to evaluate the accuracy of technical information provided by the respondents.
During the engineering review, EPA coded responses to facilitate entry of technical data into the
long survey database. The MP&M 1996 Long Survey Database Dictionary identifies the database
codes developed for this project, and is located in the MP&M Administrative Record. EPA
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contacted approximately 240 long survey respondents, by telephone and letter, to clarify
incomplete or inconsistent technical information prior to data entry.
The Agency developed a database for the technical information provided by survey
respondents. After engineering review and coding, EPA entered data from 297 long surveys into
the database using a double key-entry and verification procedure. The MP&M 1996 Long Survey
Database Dictionary presents the database structure and defines each field in the files for the long
survey database. EPA did not include data from 14 long survey respondents in the database for the
following reasons:
• The site was out of business;
The site did not use process water;
• The site was not engaged in MP&M operations; or
The site provided insufficient data and the survey was returned too late to
enter into the database.
3.1.2.3 1996 Short Detailed Survey
EPA distributed the short surveys in September 1997 to 101 MP&M wastewater-
discharging industrial facilities. EPA designed this survey to gather technical and economic
information required to develop the MP&M effluent limitations guidelines and standards. The
short survey is discussed below.
1996 Short Survey Recipient Selection and Distribution
EPA initially sent 100 short surveys in September 1997 and mailed one additional
survey to a site to replace a short survey that was returned undelivered; EPA assumed the
undeliverable site to be out of business. The Agency sent the short surveys to randomly selected
1996 screener respondents who performed operations in one of the 11 MP&M industrial sectors
identified in Section 3.1.2 and indicated they discharged less than one million gallons of MP&M
process wastewater annually. The selection criteria and sampling frame for short survey
recipients are described in more detail in the Statistical Summary for the Metal Products &
Machinery Industry Surveys.
EPA established a toll-free telephone helpline and an electronic mail address to
assist short survey recipients in completing the survey. EPA received helpline calls and electronic
mail inquiries from approximately 20 short survey recipients. Nonconfidential notes from helpline
and review follow-up calls are located in the MP&M Public Record.
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1996 Short Survey Mailout Results
Of the 101 surveys mailed, 82 percent (83 surveys) of the recipients returned
completed surveys to EPA. A blank copy of the 1996 short survey and nonconfidential portions of
the completed short surveys are located in the MP&M Public Record. Table 3-1 and Figure 3-1,
on pages 3-4 and 3-5, summarize the MP&M survey mailout results.
Information Collected
The information collected in the 1996 short survey included the identical general
site and process information and economic information collected in Sections I, II, IV, and V of the
long detailed survey (see Section 3.1.2.2). To minimize the burden on facilities discharging less
than one million gallons of process wastewater, EPA did not require these facilities to provide the
detailed information on MP&M unit operations or treatment technologies that EPA requested in
Section III of the long survey. The ICR for this project and the survey instructions have further
details on the types of information collected and the potential uses of the information.
EPA divided the short survey into the following sections:
• Section I: General Site Information;
• Section II: General Process Information;
• Section IV: Economic Information; and
• Section V: Voluntary Supplemental Information.
Table 3-2, on page 3-16, summarizes the 1996 short survey information by question number.
1996 Short Survey Data Review and Data Entry
EPA completed a detailed engineering review of Sections I and II of the short
survey to evaluate the accuracy of technical information provided by the respondents. During the
engineering review, EPA coded responses to facilitate entry of technical data into the short survey
database. The MP&M 1996 Short Survey Database Dictionary identifies the database codes
developed for this project and is located in the MP&M Administrative Record. EPA contacted
more than 60 short survey respondents, by telephone and letter, to clarify incomplete or
inconsistent technical information prior to data entry.
The Agency developed a database for the technical information provided by survey
respondents. After engineering review and coding, EPA entered data for 75 short surveys into the
database using a double key-entry and verification procedure. The MP&M 1996 Short Survey
Database Dictionary presents the database structure and defines each field in the files for the short
survey database. EPA did not include data from eight short survey respondents in the database for
the following reasons:
• The site was out of business;
The site did not use process water; or
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The site was not engaged in MP&M operations.
3.1.2.4 1996 Municipality Detailed Survey
EPA distributed the municipality surveys in June 1997 to 150 city and county
facilities that might operate MP&M facilities. EPA designed this survey to measure the impact of
this rule on municipalities and Miscellaneous government entities that perform maintenance and
rebuilding operations on MP&M products (i.e., bus and truck, automobiles, etc.).
Recipient Selection and Distribution
The Agency sent the municipality survey to 150 city and county facilities randomly
selected from the Municipality Year Book-1995 based on population and geographic location.
EPA allocated sixty percent of the sample to municipalities and 40 percent to counties. The 60/40
distribution was approximately proportional to their aggregate populations in the frame. The
Agency divided the municipality sample and the county sample into three size groupings as
measured by population. For municipalities, the population groupings were: less than 10,000
residents, 10,000 - 50,000 residents, and 50,000 or more residents. For counties, the population
groupings were: less than 50,000 residents, 50,000-150,000 residents, and 150,000 or more
residents. The geographic stratification conformed to the Census definitions of Northeast, North
Central, South, Pacific, and Mountain states.
EPA established a toll-free telephone helpline and an electronic mail address to
assist municipality survey recipients in completing the survey. EPA received helpline calls and
electronic mail inquiries from more than 50 municipality survey recipients. Notes from helpline
and review follow-up calls are located in the MP&M Administrative Record.
1996 Municipality Survey Mailout Results
EPA distributed 150 municipality surveys in June 1997. Three surveys were
returned undelivered. Of the 150 surveys mailed, 90 percent (135) of the recipients returned
completed surveys to EPA. A blank copy of the 1996 municipality survey and nonconfidential
portions of the completed municipality surveys are located in the MP&M Public Record. Table 3-
1 and Figure 3-1, on pages 3-4 and 3-5, summarize the MP&M survey mailout results.
Information Collected
The 1996 municipality survey collected economic information for the entire
municipality and site-specific process information for each MP&M site operated by the
municipality. The ICR for this project and the survey instructions contain further details on the
types of information collected and the potential uses of the information and are located in the
MP&M Administrative Record.
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EPA divided the municipality detailed survey into the following parts:
• Part I: Economic and Financial Information; and
• Part II: General Site-Specific Process Information.
Table 3-2, on page 3-16, summarizes the 1996 municipality survey information by question
number.
Part I requested information to provide the site location and contact person, number
of employees, detailed financial and economic information about the entire municipality, and
information necessary to determine if the municipality owned and operated MP&M sites in any of
the MP&M industrial sectors. Information from this section is presented in the Economic.
Environmental, and Benefits Analysis of the Proposed Metal Products & Machinery Rule, which is
located in the MP&M Administrative Record.
Part II requested site-specific process information for each MP&M site owned and
operated by the municipality. Question 1 requested the site to identify the MP&M industrial sector
and type of activity (manufacturing, rebuilding, or maintenance) performed. The remaining
questions were identical to Section II of the short detailed survey and requested facility age,
process wastewater discharge status and destination, wastewater discharge permits and permitting
authority, general information about metal types processed, MP&M products and production
levels, water use for unit operations, and wastewater discharge from unit operations. The Agency
used the process information to evaluate water use and discharge practices, and sources of
pollutants for each MP&M unit operation.
1996 Municipality Survey Data Review and Data Entry
EPA completed a detailed engineering review of Part II of the municipality survey
to evaluate the accuracy of technical information provided by the respondents. During the
engineering review, the Agency coded responses to facilitate entry of technical data into the
municipality survey database. The MP&M 1996 Municipality Survey Database Dictionary
identifies the database codes developed for this project, and is located in the MP&M
Administrative Record. EPA contacted more than 50 municipality survey respondents by
telephone to clarify incomplete or inconsistent technical information prior to data entry.
The Agency developed a database for the technical information provided by survey
respondents. After engineering review and coding, EPA entered data from 209 municipality
facilities into the database using a double key-entry and verification procedure. This number is
greater than the number of respondents because some municipalities had more than one site
engaged in MP&M operations. The MP&M 1996 Municipality Survey Database Dictionary
presents the database structure and defines each field in the files for the municipality survey
database.
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3.1.2.5 1996 Federal Facilities Detailed Survey
In April 1998, EPA distributed the federal facilities detailed survey to the
following seven federal agencies:
Department of Energy;
Department of Defense;
• National Aeronautics and Space Administration (NASA);
• Department of Transportation (including the United States Coast Guard);
Department of Interior;
Department of Agriculture; and
• United States Postal Service.
EPA designed this survey to assess the impact of the MP&M effluent limitations guidelines and
standards on federal agencies that operate MP&M facilities.
Recipient Selection and Distribution
There was no specific sampling frame for the federal survey. EPA distributed the
survey to federal agencies likely to perform industrial operations on metal products or machines.
EPA requested representatives of seven federal agencies to voluntarily distribute copies of the
survey to sites they believed performed MP&M operations. The selection criteria for federal
survey recipients are described in more detail in the ICR for the 1996 MP&M industry surveys.
Because the sample was not randomly selected, EPA did not use data from these surveys to
develop national estimates.
EPA established a toll-free telephone helpline and an electronic mail address to
assist federal survey recipients in completing the survey. EPA received helpline calls and
electronic mail inquiries from approximately 20 federal survey recipients. Nonconfidential notes
from helpline and review follow-up calls are located in the MP&M Public Record.
1996 Federal Survey Distribution Results
EPA distributed the federal surveys to seven federal agencies and requested that
they forward copies to any of their sites that performed MP&M operations. The Agency received
51 completed federal surveys. Of the 51 returned surveys, 39 were Department of Defense
facilities and 12 were NASA facilities. A blank copy of the 1996 federal survey and
nonconfidential portions of the completed federal surveys are located in the MP&M Public
Record.
Information Collected
The information collected in the 1996 federal survey was identical to the long
survey. The federal survey included the same five sections and questions discussed in Section
3.1.2.2. The ICR for this project and the survey instructions contain further details on the types of
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information collected and the potential uses of the information . Table 3-2, on page 3-22,
summarizes the 1996 federal detailed survey information by question number.
Data Review and Data Entry
EPA completed a detailed engineering review of Sections I through III of the
federal detailed survey to evaluate the accuracy of technical information provided by the
respondents. During the engineering review, the Agency coded responses to facilitate entry of
technical data into the federal survey database. The MP&M 1996 Federal Survey Database
Dictionary identifies the database codes developed for this project and is located in the MP&M
Administrative Record.
The Agency developed a database for the technical information provided by survey
respondents. After engineering review and coding, EPA entered data from 44 federal surveys into
the database using a double key-entry and verification procedure. The Agency did not include data
from seven federal survey responses in the database because the sites did not use MP&M process
water. The MP&M 1996 Federal Survey Database Dictionary presents the database structure and
defines each field in the files for the federal survey database.
3.1.2.6 1997 Iron and Steel Industry Short Survey Data
As part of its effort to review and revise effluent limitations guidelines and
standards for the iron and steel industry, EPA distributed the iron and steel industry short survey to
402 iron and steel facilities in November 1998. Following field sampling of iron and steel sites
and review of the completed industry surveys, EPA decided that some iron and steel operations
would be covered more appropriately by the MP&M rule because they were more like MP&M
operations. These operations are steel forming and surface treatment processes and include the
following:
• Acid Cleaning/Pickling;
• Alkaline Cleaning;
Annealing;
Conversion Coating (e.g., passivation, surface activation/fluxing)
• Electrolytic Cleaning
• Electroplating
Cold Forming (e.g., wire, bar, and rod drawing, pipe and tube forming)
Hot Dip Coating;
• Lube (lime, Borax, etc.)
• Painting
Salt Bath Descaling
Shot Blasting; and
Wet Air Pollution Control.
The wastewater characteristics and flows for these operations are similar to those seen in the
MP&M industry, and less like the wastewater characteristics and flows associated with
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the large, continuous flat-rolled products (e.g., sheet, strip, and plate) and the hot-forming
operations at steel manufacturing facilities.
Based on EPA's decision regarding these operations, the Agency transferred 154
iron and steel surveys to the MP&M project. Of the 154 surveys transferred, 47 sites discharge
process wastewater, 64 do not discharge process wastewater, and 43 sites discharge storm water
only. The Agency coded and entered process and wastewater treatment information from 47 iron
and steel surveys into the MP&M costing input database. The sites included in the costing effort
were sites discharging process wastewater. The 107 iron and steel zero discharge and
stormwater-only sites were not included in the costing effort. A blank copy of the 1997 iron and
steel short survey and nonconfidential portions of the 47 completed iron and steel surveys are
located in the MP&M Public Record.
3.1.2.7 1996 Publicly Owned Treatment Works (POTW) Detailed Survey
EPA distributed the POTW survey to 150 sites in November 1997. The Agency
designed this survey to estimate benefits associated with implementation of the MP&M regulations
and to estimate possible costs and burden that POTWs might incur in writing and maintaining
MP&M permits or other control mechanisms.
Recipient Selection and Distribution
The Agency sent the POTW survey to 150 POTWs with flow rates greater than 0.50
million gallons per day. EPA randomly selected the recipients from the 1992 Needs Survey
Review, Update, and Query System Database. EPA divided the POTW sample into two strata by
daily flow rates: 0.50 to 2.50 million gallons, and 2.50 million gallons or more. The selection
criteria and sampling frame for POTW survey recipients are described in more detail in the ICR
for the 1996 surveys.
EPA established a toll-free telephone helpline and an electronic mail address to
assist POTW survey recipients in completing the survey. EPA received helpline calls and
electronic mail inquiries from approximately 50 POTW survey respondents. Nonconfidential
notes from helpline and review follow-up calls are located in the MP&M Administrative Record.
1996 POTW Survey Mailout Results
EPA distributed 150 POTW surveys in November 1997. Two surveys were
returned undelivered. Of the 150 surveys mailed, 98 percent (147) of the recipients returned
completed surveys to EPA. A blank copy of the 1996 POTW survey and nonconfidential portions
of the completed POTW surveys are located in the MP&M Public Record. Table 3-1 and Figure
3-1, on pages 3-4 and 3-5, summarize the MP&M survey mailout results.
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Information Collected
The POTW survey requested data required to estimate benefits associated with
implementation of the MP&M regulations and to estimate possible costs and burden that POTWs
might incur in writing and maintaining MP&M permits or other control mechanisms. The ICR for
this project and the survey instructions contain further details on the types of information collected
and the potential uses of the information. EPA divided the POTW survey into the following parts:
Part I: Introduction and Basic Information;
Part II: Administrative Permitting Costs; and
• Part III: Sewage Sludge Use or Disposal Costs.
Part I requested site location and contact information, and the total volume of
wastewater treated at the site. EPA used the wastewater flow information to characterize the size
of the POTW.
Part II requested the number of industrial permits written, the cost to write the
permits, the permitting fee structure, the percentage of industrial dischargers covered by National
Categorical Standards (i.e., effluent guidelines), and the percentage of permits requiring expensive
administrative activities. EPA used this information to estimate administrative burden and costs.
Part III requested information on the use or disposal of sewage sludge generated by
the POTW. EPA required only POTWs that received discharges from an MP&M facility to
complete Part III. The sewage sludge information requested included the amount generated, use or
disposal method, metal levels, use or disposal costs, and the percentage of total metal loadings at
the POTW from MP&M facilities. The Agency used this information to assess the potential
changes in sludge handling resulting from the MP&M rule and to estimate economic benefits to the
POTW related to sludge disposal and reduction in upsets/interference.
Data Review and Data Entry
EPA performed a detailed review of Parts I through III of the POTW detailed
survey to evaluate the accuracy of information provided by the respondents. During review, the
Agency coded responses to facilitate entry of data into the POTW detailed survey database. The
database dictionary for the POTW survey identifies the database codes developed for this project,
and is located in the MP&M Administrative Record. EPA contacted more than 95 POTW survey
respondents by telephone to clarify incomplete or inconsistent information prior to data entry.
The Agency developed a database for the information provided by survey
respondents. After review and coding, EPA entered data from 147 POTW surveys into the
database using a double key-entry and verification procedure. The database dictionary presents
the database structure and defines each field in the files for the POTW survey database.
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3.2
Site Visits
The Agency visited 201 MP&M sites between 1986 and 1999 to collect
information about MP&M unit operations, water use practices, pollution prevention and treatment
technologies, and waste disposal methods, and to evaluate sites for potential inclusion in the
MP&M sampling program (described in Section 3.3). In general, the Agency visited sites to
encompass the range of sectors, unit operations, and wastewater treatment technologies within the
MP&M industry (discussed in Section 3.2.1). Table 3-3 lists the number of sites visited within
each MP&M sector. The total number of site visits presented in this table exceeds 201 because
EPA classified some sites in multiple sectors. Figure 3-2 presents the number of MP&M sites
visited and sampled by industrial sector.
Table 3-3
Number of Sites Visited Within Each MP&M Sector
Industrial Sectors
Aerospace
Aircraft
Bus and Truck
Electronic Equipment
Hardware
Household Equipment
Instrument
Job Shops
Mobile Industrial Equipment
Total
Number of
Sites Visited
13
32
8
22
15
4
4
20
7
Industrial Sectors
Motor Vehicle
Office Machines
Ordnance
Precious Metals and Jewelry
Printed Wire Boards
Railroad
Ships and Boats
Stationary Industrial Equipment
Miscellaneous Metal Products
Total
Number of
Sites Visited
20
5
15
2
9
10
7
14
0
Source: MP&M Site Visits.
3.2.1
Criteria for Site Selection
The Agency based site selection on information contained in the MP&M screener
and detailed surveys. The Agency also contacted regional EPA personnel, state environmental
agency personnel, and local pretreatment coordinators to identify MP&M sites believed to be
operating in-process source reduction and recycling technologies and/or well-operated end-of-
pipe wastewater treatment technologies.
The Agency used the following four general criteria to select sites that
encompassed the range of sectors and unit operations within the MP&M industry.
1. The site performed MP&M unit operations in one of the industrial sectors.
To assess the variation of unit operations and water use practices across
sectors, the Agency visited sites in each of the MP&M sectors.
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Stationary Industrial Equipment
Ships and Boats
Railroad
Printed Wire Boards
Precious Metals and Jewelry
Ordnance
Office Machines
Motor Vehicles
Mobile Industrial Equipment
Miscellaneous Metal Products
Job Shop Metal Finishing
Instruments
Household Equipment
Hardware
Electronic Equipment
Bus and Truck
Aircraft
Aerospace
D Number of Sites Sampled
• Number of Sites Visited
15 20
Number of Sites
Figure 3-2. Number of MP&M Sites Visited and Sampled by Industrial Sector
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3.0 - Data Collection Activities
2. The site performed MP&M unit operations that needed to be characterized
for development of the regulation.
3. The site had water use practices that were believed to be representative of
the best sites within an industrial sector.
4. The site operated in-process source reduction, recycling, or end-of-pipe
treatment technologies EPA was evaluating in developing the MP&M
technology options.
The Agency also attempted to visit sites of various sizes. EPA visited sites with
wastewater flows ranging from less than 200 gpd to more than 1,000,000 gpd.
Site-specific selection criteria are discussed in site visit reports (SVRs) prepared
for each site visited by EPA. The SVRs are located in the MP&M Administrative Record.
3.2.2 Information Collected
During the site visits, EPA collected the following types of information:
• Unit operations performed at the site and the types of metals processed
through these operations;
• Purpose of unit operations performed and purpose for any process water
and chemical additions used by the unit operations;
Types and disposition of wastewater generated at the site;
• Types of in-process source reduction and recycling technologies performed
at the site;
• Cross-media impacts of in-process source reduction and recycling
technologies;
Types of end-of-pipe treatment technologies performed at the site; and
• Logistical information required for sampling.
This information is documented in the SVRs for each site. Non-confidential SVRs can be found in
the MP&M Public Record.
3.3 Wastewater and Solid Waste Sampling
The Agency conducted sampling episodes at 72 sites between 1986 and 1999 to
obtain data on the characteristics of MP&M wastewater and solid wastes. In addition, EPA
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performed sampling episodes to assess the following: the loading of pollutants to surface waters
and POTWs from MP&M sites; the effectiveness of technologies designed to reduce and remove
pollutants from MP&M wastewater; and the variation of MP&M wastewater characteristics across
unit operations, metal types processed in each unit operation, and sectors. Table 3-4 indicates the
number of sites sampled within each MP&M sector. The number of sampled sites presented in the
table does not equal 72 because EPA conducted multiple sampling episodes at some sites, and
EPA classified some sites in multiple sectors. Figure 3-2 on page 3-27 presents the number of
sites visited and sampled by industrial sector.
Table 3-4
Number of Sites Sampled Within Each MP&M Sector
Industrial Sectors
Aerospace
Aircraft
Bus and Truck
Electronic Equipment
Hardware
Household Equipment
Instruments
Job Shops
Mobile Industrial Equipment
Total Number
of Sites
Sampled
2
9
4
4
4
2
2
8
2
Industrial Sectors
Motor Vehicle
Office Machines
Ordnance
Precious Metals and Jewelry
Printed Wiring Boards
Railroad
Ships and Boats
Stationary Industrial Equipment
Miscellaneous Metal Products
Total Number
of Sites
Sampled
9
2
3
2
3
4
3
4
0
Source: MP&M Sampling Episodes.
3.3.1 Criteria for Site Selection
The Agency used information collected during MP&M site visits to identify
candidate sites for sampling. The Agency used the following general criteria to select sites for
sampling:
• The site performed MP&M unit operations EPA was evaluating for
development of the MP&M regulation;
• The site processed metals through MP&M unit operations for which the
metal type/unit operation combination needed to be characterized for the
sampling database;
The site performed in-process source reduction, recycling, or end-of-pipe
treatment technologies that EPA was evaluating for technology option
development; and
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The site performed unit operations in a sector that EPA was evaluating for
development of the MP&M regulation.
The Agency also attempted to sample at sites of various sizes. EPA sampled at sites with
wastewater flows ranging from less than 200 gpd to more than 1,000,000 gpd.
After EPA selected a site for sampling, the Agency prepared a detailed sampling
and analysis plan (SAP), based on the information contained in the SVR and follow-up
correspondence with the site. EPA prepared the SAPs to ensure collection of samples that would
be representative of the sampled waste streams. The SAPs contained the following types of
information: site-specific selection criteria for sampling; information about site operations;
sampling point locations and sample collection, preservation, and transportation procedures; site
contacts; and sampling schedules.
3.3.2 Information Collected
In addition to wastewater and solid waste samples, the Agency collected the
following types of information during each sampling episode:
• Dates and times of sample collection;
Flow data corresponding to each sample;
• Production data corresponding to each sample of wastewater from MP&M
unit operations;
Design and operating parameters for source reduction, recycling, and
treatment technologies characterized during sampling;
Information about site operations that had changed since the site visit or that
were not included in the SVR; and
• Temperature and pH of the sampled waste streams.
EPA documented all data collected during sampling episodes in the sampling
episode report (SER) for each sampled site. Nonconfidential SERs are located in the MP&M
Public Record. Many of the SERs also contain preliminary technical analyses of treatment system
performance (where applicable) as compared to treatment performance data collected for previous
metals industry regulatory development efforts.
3.3.3 Sample Collection and Analysis
The Agency collected, preserved, and transported all samples according to EPA
protocols as specified in EPA's Sampling and Analysis Procedures for Screening of Industrial
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Effluents for Priority Pollutants (1) and the MP&M Quality Assurance Project Plan (QAPP).
These documents are located in the MP&M Administrative Record.
In general, EPA collected composite samples from wastewater streams with
compositions that the Agency expected to vary over the course of a production period (e.g.,
overflowing rinse waters, wastewater from continuous recycling and treatment systems). The
Agency collected grab samples from unit operation baths or rinses that the facility did not
continuously discharge and the Agency did not expect to vary over the course of a production
period. EPA also collected composite samples of wastewater treatment sludge at 11 facilities.
EPA collected the required types of quality control samples as described in the MP&M QAPP,
such as blanks and duplicate samples, to verify the precision and accuracy of sample analyses.
The Agency shipped samples via overnight air transportation to EPA-approved
laboratories, where the samples were analyzed for metal and organic pollutants and additional
parameters (including several water quality parameters). EPA analyzed metal pollutants using
EPA Method 1620 (2), volatile organic pollutants using EPA Method 1624 (3), and semivolatile
organic pollutants using EPA Method 1625 (4). Tables 3-5 and 3-6 list the metal and organic
pollutants, respectively, analyzed using these methods. Table 3-5 also lists additional metal
pollutants that EPA analyzed in the MP&M sampling program, but, as specified by EPA Method
1620, were not subject to the rigorous quality assurance/quality control procedures established by
the QAPP. The Agency used these metals analyses for screening purposes and did not select the
metals for regulation in this rulemaking (see Section 7.0). EPA analyzed additional parameters,
including several water quality parameters, using analytical methods contained in EPA's Methods
for Chemical Analysis of Water and Wastes (5). Table 3-7 lists these parameters, along with the
method and technique used to analyze for each parameter. Method descriptions are included in the
MP&M QAPP. The specific parameters measured in each sample are listed in the SER for each
sampling episode.
Quality control measures used in performing all analyses complied with the
guidelines specified in the analytical methods and in the MP&M QAPP. EPA reviewed all
analytical data to ensure that these measures were followed and that the resulting data were within
the QAPP-specified acceptance criteria for accuracy and precision.
As discussed previously, upon receipt and review of the analytical data for each
site, EPA prepared an SER to document the data collected during sampling, the analytical results,
and the technical analyses of the results. The SAPs and correspondence with site personnel are
included as appendices to the SERs.
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Table 3-5
Metal Constituents Measured Under the MP&M Sampling Program
(EPA Method 1620)
Metal Constituents
ALUMINUM
ANTIMONY
ARSENIC
BARIUM
BERYLLIUM
BORON
CADMIUM
CALCIUM
CHROMIUM
COBALT
COPPER
IRON
LEAD
MAGNESIUM
MANGANESE
MERCURY
MOLYBDENUM
NICKEL
SELENIUM
SILVER
SODIUM
THALLIUM
TIN
TITANIUM
VANADIUM
YTTRIUM
ZINC
Additional Metal Constituents3 Not Subject to Rigorous QA/QC Procedures Per Method 1620
BISMUTH
CERIUM
DYSPROSIUM
ERBIUM
EUROPIUM
GADOLINIUM
GALLIUM
GERMANIUM
GOLD
HAFNIUM
HOLMIUM
INDIUM
IODINE
IRIDIUM
LANTHANUM
LITHIUM
LUTETIUM
NEODYMIUM
NIOBIUM
OSMIUM
PALLADIUM
PHOSPHORUS
PLATINUM
POTASSIUM
PRASEODYMIUM
RHENIUM
RHODIUM
RUTHENIUM
SAMARIUM
SCANDIUM
SILICON
STRONTIUM
SULFUR
TANTALUM
TELLURIUM
TERBIUM
THORIUM
THULIUM
TUNGSTEN
URANIUM
YTTERBIUM
ZIRCONIUM
"Analyses for these metals were used for screening purposes, and the metals were not selected for regulation in
this rulemaking.
Source: EPA Method 1620.
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Table 3-6
Organic Constituents Measured Under the MP&M Sampling Program
(EPA Methods 1624 and 1625)
Volatile Organic Constituents (EPA Method 1624)
ACRYLONITRILE
BENZENE
BROMODICHLOROMETHANE
BROMOMETHANE
CARBON DISULFIDE
CHLOROACETONITRILE
CHLOROBENZENE
CHLOROETHANE
CHLOROFORM
CHLOROMETHANE
CIS- 1 ,3-DICHLOROPROPENE
CROTONALDEHYDE
DIBROMOCHLOROMETHANE
DIBROMOMETHANE
DIETHYL ETHER
ETHYL CYANIDE
ETHYL METHACRYLATE
ETHYLBENZENE
IODOMETHANE
ISOBUTYL ALCOHOL
M-XYLENE
METHYL METHACRYLATE
METHYLENE CHLORIDE
O+P-XYLENE
TETRACHLOROETHENE
TETRACHLOROMETHANE
TOLUENE
TRANS- 1 ,2-DICHLOROETHENE
TRANS-1,3-DICHLOROPROPENE
TRANS- 1 ,4-DICHLORO-2-BUTENE
TRIBROMOMETHANE
TRICHLOROETHENE
TRICHLOROFLUOROMETHANE
VINYL ACETATE
VINYL CHLORIDE
, -DICHLOROETHANE
, -DICHLOROETHENE
, ,1-TRICHLOROETHANE
, ,1,2-TETRACHLOROETHANE
, ,2-TRICHLOROETHANE
, ,2,2-TETRACHLOROETHANE
,2-DIBROMOETHANE
,2-DICHLOROETHANE
,2-DICHLOROPROPANE
,2,3-TRICHLOROPROPANE
,3-BUTADIENE, 2-CHLORO
,3-DICHLOROPROPANE
,4-DIOXANE
2-BUTANONE
2-CHLOROETHYL VINYL ETHER
2-HEXANONE
2-PROPANONE
2-PROPEN-l-OL
2-PROPENAL
2-PROPENENITRILE, 2-METHYL-
3-CHLOROPROPENE
4-METHYL-2-PENTANONE
Semivolatile Organic Constituents (EPA Method 1625)
ACENAPHTHENE
ACENAPHTHYLENE
ACETOPHENONE
ALPHA-TERPINEOL
ANILINE
ANILINE, 2,4,5-TRIMETHYL-
ANTHRACENE
ARAMITE
BENZANTHRONE
BENZENETHIOL
BENZO(A)ANTHRACENE
BENZO(A)PYRENE
BENZO(B)FLUORANTHENE
BENZO(GHI)PERYLENE
BENZO(K)FLUORANTHENE
BENZOIC ACID
BENZONITRILE, 3,5-DIBROMO-4-HYDROXY-
BENZYL ALCOHOL
BETA-NAPHTHYLAMINE
BIPHENYL
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3.0 - Data Collection Activities
Table 3-6 (Continued)
Semivolatile Organic Constituents (EPA Method 1625)
BENZIDINE
BIS(2-CHLOROETHOXY)METHANE
BIS(2-CHLOROETHYL) ETHER
BIS(2-CHLOROISOPROPYL) ETHER
BIS(2-ETHYLHEXYL) PHTHALATE
BUTYL BENZYL PHTHALATE
CARBAZOLE
CHRYSENE
CIODRIN
CROTOXYPHOS
DI-N-BUTYL PHTHALATE
DI-N-OCTYL PHTHALATE
DI-N-PROPYLNITROSAMINE
DIBENZO(A,H) ANTHRACENE
DIBENZOFURAN
DIBENZOTHIOPHENE
DIETHYL PHTHALATE
DIMETHYL PHTHALATE
DIMETHYL SULFONE
DIPHENYL ETHER
DIPHENYLAMINE
DIPHENYLDISULFIDE
ETHANE, PENTACHLORO-
ETHYL METHANESULFONATE
ETHYLENETHIOUREA
FLUORANTHENE
FLUORENE
HEXACHLOROBENZENE
HEXACHLOROBUTADIENE
HEXACHLOROCYCLOPENTADIENE
HEXACHLOROETHANE
HEXACHLOROPROPENE
HEXANOIC ACID
INDENO( 1,2,3 -CD)PYRENE
ISOPHORONE
ISOSAFROLE
LONGIFOLENE
MALACHITE GREEN
MESTRANOL
METHAPYRILENE
METHYL METHANESULFONATE
N-DECANE
N-DOCOSANE
N-DODECANE
STYRENE
THIANAPHTHENE
THIOACETAMIDE
THIOXANTHE-9-ONE
TOLUENE, 2,4-DIAMINO-
BIPHENYL, 4-NITRO
N-EICOSANE
N-HEXACOSANE
N-HEXADECANE
N-NITROSODI-N-BUTYLAMINE
N-NITROSODIETHYLAMINE
N-NITROSODIMETHYLAMINE
N-NITROSODIPHENYLAMINE
N-NITROSOMETHYLETHYLAMINE
N-NITROSOMETHYLPHENYLAMINE
N-NITROSOMORPHOLINE
N-NITROSOPIPERIDINE
N-OCTACOSANE
N-OCTADECANE
N-TETRACOSANE
N-TETRADECANE
N-TRIACONTANE
N,N-DIMETHYLFORMAMIDE
NAPHTHALENE
NITROBENZENE
O-ANISIDINE
O-CRESOL
O-TOLUIDINE
O-TOLUIDINE, 5-CHLORO-
P-CHLOROANILINE
P-CRESOL
P-CYMENE
P-DIMETHYLAMINOAZOBENZENE
P-NITROANILINE
PENTACHLOROBENZENE
PENTACHLOROPHENOL
PENTAMETHYLBENZENE
PERYLENE
PHENACETIN
PHENANTHRENE
PHENOL
PHENOL, 2-METHYL-4,6-DINITRO-
PHENOTHIAZINE
PRONAMIDE
PYRENE
PYRIDINE
RESORCINOL
SAFROLE
SQUALENE
2-NITROANILINE
2-NITROPHENOL
2-PHENYLNAPHTHALENE
2-PICOLINE
2,3-BENZOFLUORENE
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3.0 - Data Collection Activities
Table 3-6 (Continued)
Semivolatile Organic Constituents (EPA Method 1625)
1 -BROMO-2-CHLOROBENZENE
l-BROMO-3-CHLOROBENZENE
l-CHLORO-3-NITROBENZENE
1 -METHYLFLUORENE
1 -METHYLPHEN ANTHRENE
1-NAPHTHYLAMINE
1 -PHENYLN APHTHALENE
l,2-DIBROMO-3-CHLOROPROPANE
1,2-DICHLOROBENZENE
1,2-DIPHENYLHYDRAZINE
1,2,3-TRICHLOROBENZENE
1,2,3-TRIMETHOXYBENZENE
1,2,4-TRICHLOROBENZENE
1,2,4,5 -TETRACHLOROBENZENE
1,2:3,4-DIEPOXYBUTANE
l,3-DICHLORO-2-PROPANOL
1,3-DICHLOROBENZENE
1,3,5-TRITHIANE
1,4-DICHLOROBENZENE
1,4-DINITROBENZENE
1,4-NAPHTHOQUINONE
1,5-NAPHTHALENEDIAMINE
2-(METHYLTHIO)BENZOTHIAZOLE
2-CHLORONAPHTHALENE
2-CHLOROPHENOL
2-ISOPROPYLNAPHTHALENE
2-METHYLBENZOTHIOAZOLE
2-METHYLNAPHTHALENE
2,3,4,6-TETRACHLOROPHENOL
2,3,6-TRICHLOROPHENOL
2,4 -DICHLOROPHENOL
2,4-DIMETHYLPHENOL
2,4-DINITROPHENOL
2,4-DINITROTOLUENE
2,4,5-TRICHLOROPHENOL
2,4,6-TRICHLOROPHENOL
2,6-DI-TERT-BUTYL-P-BENZOQUINONE
2,6-DICHLORO-4-NITROANILINE
2,6-DICHLOROPHENOL
2,6-DINITROTOLUENE
3-METHYLCHOLANTHRENE
3-NITROANILINE
3,3'-DICHLOROBENZIDINE
3,3'-DIMETHOXYBENZIDINE
3,6-DIMETHYLPHENANTHRENE
4-AMINOBIPHENYL
4-BROMOPHENYL PHENYL ETHER
4-CHLORO-2-NITROANILINE
4-CHLORO-3-METHYLPHENOL
4-CHLOROPHENYL PHENYL ETHER
4-NITROPHENOL
4,4'-METHYLENEBIS(2-CHLOROANILINE)
4,5-METHYLENE PHENANTHRENE
5-NITRO-O-TOLUIDINE
7,12-DIMETHYLBENZ(A)ANTHRACENE
Source: EPA Methods 1624 and 1625.
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3.0 - Data Collection Activities
Table 3-7
Additional Parameters Measured Under the MP&M Sampling Program
Parameter
Acidity
Alkalinity
Ammonia as Nitrogen
BOD 5 -Day (Carbonaceous)
Chemical Oxygen Demand (COD)
Chloride
Cyanide, Total
Cyanide, Amenable
Fluoride
Nitrogen, Total Kjeldahl
Oil and Grease
Oil and Grease (as HEM)
pH
Phenolics, Total Recoverable
Phosphorus, Total
Sulfate
Sulfide, Total
Total Dissolved Solids (TDS)
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbons (as SGT-HEM)
Total Suspended Solids (TSS)
Ziram
EPA Method
305.1
310.1
350.1
405.1
410.1
410.2
325.3
335.2
335.1
340.2
351.2
413.2
1664
150.1
420.2
365.4
375.4
376.1,376.2
160.1
415.1
1664
160.2
630.1
Source: EPA Methods for Chemical Analysis of Water and Wastes.
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3.0 - Data Collection Activities
3.4 Other Sampling Data
Extension of the MP&M effluent guidelines schedule, as discussed in Section 2.2,
allowed more stakeholder involvement for data collection. The Association of American
Railroads (AAR), the Hampton Roads Sanitation District (HRSD), and the Los Angeles County
Sanitation Districts (LACSD) proposed potential sampling sites to the Agency, and EPA visited
these sites to identify candidates for sampling. After conducting site visits, EPA selected five sites
for sampling episodes.
EPA selected the five sites to characterize end-of-pipe treatment technologies in
metal finishing and aircraft parts job shops and the railroad and shipbuilding industrial sectors.
The site sampled by AAR performs railroad line maintenance and uses dissolved air flotation
(DAF) to treat MP&M process wastewater. The site sampled by HRSD manufactures ships and
boats and uses DAF, chemical precipitation, and cyanide destruction to treat process wastewater.
The three sites sampled by LACSD were two metal finishing job shops and one aircraft parts
manufacturing job shop. EPA selected the LACSD sites to provide data for cyanide treatment and
also conducted effluent variability sampling at one of the metal finishing job shops.
EPA prepared detailed SAPs based on the information collected during the five
site visits, and AAR, HRSD and LACSD collected the wastewater samples. EPA also prepared
the sampling episode reports. In addition to the wastewater samples, sampling personnel obtained
the collection date and time, sample flow data, treatment unit design and operating parameters, and
temperature and pH of the sampled waste streams. All data collected during sampling episodes
are documented in the SER for each sampled site which are located in the MP&M Administrative
Record. The SERs also contain preliminary technical analyses of treatment system performance
(where applicable) as compared to treatment performance data collected for previous metals
industry regulatory development efforts. EPA combined these data with data collected from the
MP&M sampling program.
EPA collected, preserved, and transported all samples according to EPA protocols
as specified in EPA's Sampling and Analysis Procedures for Screening of Industrial Effluents for
Priority Pollutants and the MP&M QAPP. Shipping and analysis of the samples were similar to
that discussed in Section 3.3 with the exception that some samples were shipped directly to
internal sanitation district laboratories for analysis. Pollutant parameters and analytical methods
were agreed upon by EPA, AAR, HRSD, and LACSD and were treated as equivalent to the EPA
MP&M sampling program.
3.5 Other Industry-Supplied Data
EPA evaluated other industry data in developing the MP&M effluent guidelines.
The data sources reviewed included public comments to the 1995 MP&M Phase I proposed rule,
the Metal Finishing F006 Benchmark Study (8), data supporting the Final Rule for the F006
Accumulation Time Extension (65 FR 12377, March 8, 2000), data provided by the Aluminum
Anodizing Council (AAC), the American Wire Producers Association (AWPA), and the
Aerospace Association. EPA also reviewed data from storm water pollution prevention plans
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3.0 - Data Collection Activities
provided by several shipbuilding sites, dry dock data from a shipbuilding site, and data from
periodic compliance monitoring reports/discharge monitoring reports for 14 sites that were part of
the Agency's wastewater sampling program. Data submitted with the MP&M Phase I comments
did not include the quality control data required to verify the accuracy of sample analyses and,
therefore, EPA did not use the data.
3.6 Other Data Sources
In developing the MP&M effluent guidelines, EPA evaluated the following existing
data sources:
1. EPA Engineering and Analysis Division (EAD) databases from
development of effluent guidelines for Miscellaneous metals industries;
2. The Office of Research and Development (ORD) National Risk
Management and Research Laboratory (NRMRL) treatability database;
3. The Fate of Priority Pollutants in Publicly Owned Treatment Works (50
POTW Study) database;
4. The Domestic Sewage Study; and
5. The Toxics Release Inventory (TRI) database.
These data sources and their uses for the development of the MP&M effluent guidelines are
discussed below.
3.6.1 EPA/EAD Databases
As discussed in Section 2.0, EPA has promulgated effluent guidelines for 13
metals industries. In developing these past effluent guidelines, EPA collected wastewater samples
to characterize the unit operations and treatment systems at sites in these industries. MP&M sites
operate many of the same or similar sampled unit operations and treatment systems; therefore, EPA
evaluated these data for transfer to the MP&M effluent guidelines development effort.
For the MP&M pollutant loading and wastewater characterization efforts, EPA
reviewed the data collected for unit operations performed at both MP&M sites and at sites in the
other metals industries. EPA reviewed the Technical Development Documents (TDDs), sampling
episode reports, and supporting rulemaking record materials for the other metals industries to
identify available data. EPA used these data for the preliminary assessment of the MP&M
industry, but did not use these data for the MP&M pollutant loadings because EPA obtained
sufficient data from the MP&M sampling program to characterize the MP&M unit operations.
For the MP&M technology effectiveness assessment effort, EPA reviewed
sampling data collected to characterize treatment systems for the development of effluent
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3.0 - Data Collection Activities
guidelines for Miscellaneous metals industries. For several previous effluent guidelines, EPA
used treatment data from metals industries to develop the Combined Metals Database (CMDB),
which served as the basis for developing limits for these industries. EPA also developed a
separate database used as the basis for limits for the Metal Finishing category. EPA used the
CMDB and Metal Finishing data as a guide in identifying well-designed and well-operated
MP&M treatment systems. EPA did not use these data in developing the MP&M technology
effectiveness concentrations, since the Agency collected sufficient data from MP&M sites to
develop technology effectiveness concentrations.
3.6.2 Fate of Priority Pollutants in Publicly Owned Treatment Works Database
In September 1982, EPA published the Fate of Priority Pollutants in Publicly
Owned Treatment Works (6), referred to as the 50 POTW Study. The purpose of this study was to
generate, compile, and report data on the occurrence and fate of the 129 priority pollutants in 50
POTWs. The report presents all of the data collected, the results of preliminary evaluations of
these data, and the results of calculations to determine the following:
The quantity of priority pollutants in the influent to POTWs;
• The quantity of priority pollutants discharged from the POTWs;
The quantity of priority pollutants in the effluent from intermediate process
streams; and
• The quantity of priority pollutants in the POTW sludge streams.
EPA used the data from this study as one of the ways to assess removal by POTWs of MP&M
pollutants of concern. To provide consistency for data analysis and establishment of removal
efficiencies, EPA reviewed the 50-POTW Study and standardized the reported minimum levels of
quantitation (MLs) for use in the MP&M proposed rule. EPA's review of the 50-POTW Study is
described in more detail in Section 7.3.1, in the appendices to Section 7, and in memoranda
located in Section 6.4 of the MP&M Public Record.
3.6.3 National Risk Management Research Laboratory (NRMRL) Treatability
Database
EPA's Office of Research and Development (ORD) developed the NRMRL
(formerly RREL) treatability database to provide data on the removal and destruction of chemicals
in various types of media, including water, soil, debris, sludge, and sediment. This database
contains treatability data from POTWs as well as industrial facilities for various pollutants. The
database includes physical and chemical data for each pollutant, the types of treatment used to treat
the specific pollutants, the types of wastewater treated, the size of the POTW or industrial plant,
and the treatment concentrations achieved. EPA used the NRMRL database to estimate pollutant
reductions achieved by POTWs for MP&M pollutants of concern that were not found in the 50-
POTW database. The Agency used these prcent removal estimates in calculating the pollutant
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3.0 - Data Collection Activities
loads removed by indirect dishcarging MP&M facilities. Because the 50-POTW database
contained sufficient data, EPA did not use these percent removal estimates in the pass-through
analysis. EPA used only treatment technologies representative of typical POTW secondary
treatment operations (i.e., activated sludge, activated sludge with filtration, aerated lagoons). The
Agency further edited these files to include information pertaining only to domestic or industrial
wastewater. The Agency used these percent removal estimates in calculating the pollutant loads
removed by indirect discharging MP&M facilities. Because the 50-POTW database contained
sufficient data, EPA did not use these percent removal estimates in the pass-through analysis. EPA
used pilot-scale and full-scale data, and eliminated bench-scale data and data from less reliable
references.
3.6.4 The Domestic Sewage Study
In February 1986, EPA issued the Report to Congress on the Discharge of
Hazardous Wastes to Publicly Owned Treatment Works (7), referred to as the Domestic Sewage
Study (DSS). This report, which was based in part on the 50 POTW Study, revealed a significant
number of sites discharging pollutants to POTWs. These pollutants are a threat to the treatment
capability of the POTW. These pollutants were not regulated by national effluent regulations.
Some of the major sites identified were in the metals industries, particularly one called equipment
manufacturing and assembly. This industry included sites that manufacture such products as office
machines, household appliances, scientific equipment, and industrial machine tools and equipment.
The DSS estimated that this category discharges 7,715 metric tons per year of priority hazardous
organic pollutants, which are presently unregulated. Data on priority hazardous metals discharges
were unavailable for this category. Further review of the DSS revealed Miscellaneous categories
that were related to metals industries, namely the motor vehicle category, which includes servicing
of new and used cars and engine and parts rebuilding, and the transportation services category,
which includes railroad operations, truck service and repair, and aircraft servicing and repair.
EPA used the information in the DSS in developing the 1989 Preliminary Data Summary (PDS) for
the MP&M category.
3.6.5 Toxics Release Inventory (TRI) Database
The TRI database contains specific toxic chemical release and transfer information
from manufacturing facilities throughout the United States. This database was established under
the Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA), which Congress
passed to promote planning for chemical emergencies and to provide information to the public
about the presence and release of toxic and hazardous chemicals. Each year, manufacturing
facilities meeting certain activity thresholds must report the estimated releases and transfers of
listed toxic chemicals to EPA and to the state or tribal entity in whose jurisdiction the facility is
located. The TRI list includes more than 300 chemicals in 20 chemical categories.
EPA considered using the TRI database in developing the MP&M effluent
guidelines. However, EPA did not use TRI data on wastewater discharges from MP&M sites
because sufficient data were not available for effluent guidelines development. For example, in
developing the MP&M effluent guidelines, EPA uses wastewater influent concentrations to
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3.0 - Data Collection Activities
characterize a facility's wastewater and to calculate treatment efficiency (i.e., percent removal
across the treatment system). The TRI database does not provide concentrations for the influent to
a facility's treatment system. EPA also did not use the data on wastewater discharge because
many MP&M sites do not meet the reporting thresholds for the TRI database.
3.7 References
1. U.S. Environmental Protection Agency. Sampling and Analysis Procedures for
Screening of Industrial Effluents for Priority Pollutants. April 1977.
2. U.S. Environmental Protection Agency. Method 1620 Draft - Metals by
Inductively Coupled Plasma Atomic Emission Spectroscopy and Atomic
Absorption Spectroscopy. September 1989.
3. U.S. Environmental Protection Agency. Method 1624 Revision C - Volatile
Organic Compounds by Isotope Dilution GCMS. June 1989.
4. U.S. Environmental Protection Agency. Method 1625 Revision C - Semivolatile
Organic Compounds by Isotope Dilution GCMS. June 1989.
5. U.S. Environmental Protection Agency. Methods for Chemical Analysis of Water
and Wastes. EPA-600/4-79-020, Washington, DC, March 1979.
6. U.S. Environmental Protection Agency. Fate of Priority Pollutants in Publicly
Owned Treatment Works. EPA 440/1-82/303, Washington, DC, September, 1982.
7. U.S. Environmental Protection Agency. Report to Congress on the Discharge of
Hazardous Wastes to Publicly Owned Treatment Works. EPA 530-SW-86-004,
Washington, DC, February 1986.
8. U.S. Environmental Protection Agency. Metal Finishing F006 Benchmark Study.
Washington, DC, September 1998.
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4.0 - Industry Description
4.0 INDUSTRY DESCRIPTION
As discussed in Section 3.0, the MP&M Point Source Category covers sites that
perform manufacturing, rebuilding, or maintenance activities while processing metal parts,
machinery, or metal products. The category includes 18 industrial sectors: aerospace, aircraft,
bus and truck, electronic equipment, hardware, household equipment, instruments, job shops,
miscellaneous metal products, mobile industrial equipment, motor vehicle, office machines,
ordnance, precious metals and jewelry, printed wiring boards, railroad, ships and boats, and
stationary industrial equipment.
This section describes the MP&M industry. Section 4.1 presents an overview of
the industry; Section 4.2 provides a general discussion of unit operations performed, metal types
processed, and volumes of wastewater discharged; Section 4.3 discusses trends in the industry;
and Section 4.4 lists the references used for Section 4.
4.1 Overview of the Industry
This section discusses the MP&M industry, including the number and size of
MP&M sites, the geographic distribution of these sites, the number of wastewater discharging
sites, and the number of non-wastewater-discharging sites.
4.1.1 Number and Size of MP&M Sites
Based on the MP&M survey database, there are approximately 89,000 MP&M
sites in the United States. Based on detailed survey results, approximately 63,000 MP&M sites
discharge process wastewater. The remaining 26,000 sites fall into one of three categories: zero
dischargers, non-water-users, or contract haulers.
MP&M wastewater-discharging sites range in size from sites with less than 10
employees to sites with tens of thousands of employees, and with wastewater discharge flow
rates of less than 100 gallons per year to more than 100 million gallons per year. The following
figure summarizes the estimated number of wastewater-discharging MP&M sites by number of
employees and estimated total discharge flow. This shows that approximately 92 percent of
MP&M sites have 500 or fewer employees and approximately 78 percent have 100 or fewer
employees.
As shown in Figure 4-1 the number of employees at a site does not necessarily
correspond with the discharge flow at the site. [This is demonstrated by the fact that sites with
greater than 500 employees account for only 38 percent of the total industry flow.] Section 4.1.3
presents additional information on the estimated number of MP&M sites by discharge flow
range.
4-1
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4.0 - Industry Description
DEstimated MP&M Wastewater-Discharging Sites
• Estimated MP&M Discharge Flow
<=10
11-50
51-100
101-500 501-1,000
Number of Employees
1,001-5,000 5,001-10,000
>10,000
4.1.2
Source: MP&M Survey Database.
Note: There are 62,749 wastewater-discharging MP&M sites. Total MP&M wastewater flow is
122 billion gallons per year.
Figure 4-1. MP&M Wastewater-Discharging Sites by Number of Employees
and Estimated Total Discharge Flow
Geographic Distribution
MP&M wastewater-discharging facilities are located throughout the United
States. EPA received survey data from all 10 EPA regions and from 48 states. MP&M facilities
are mostly concentrated in industrialized areas, with the highest concentration of facilities in
California, Pennsylvania, and Illinois. The following map shows the estimated number of
MP&M facilities located in each EPA region.
4-2
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4.0 - Industry Description
#]= EPA Region number
3= Number of Wastewater-Discharging
MP&M Sites in EPA Region
4.1.3
Figure 4-2. Estimated Number of MP&M Facilities by EPA Region
Wastewater-Discharging Sites
The MP&M category includes 18 industrial sectors. Table 4-1 summarizes the
number of MP&M wastewater-discharging sites by sector. Because some sites perform
operations in more than one sector, the sum of wastewater-discharging sites by sector exceeds the
total number of wastewater-discharging sites identified in the survey. As indicated in Table 4-1,
the railroad sector has the smallest number of wastewater-discharging sites (97) and the job
shops sector has the largest number of wastewater-discharging sites (33,683).
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4.0 - Industry Description
Table 4-1
MP&M Wastewater-Discharging Sites by Sector
Sector
Estimated Number of Sites That Discharge
Process Waste Water3
Aerospace
Aircraft
Bus and Truck
Electronic Equipment
Hardware
Household Equipment
Instruments
Iron and Steel °
Job Shopb
Miscellaneous Metal Products
Mobile Industrial Equipment
Motor Vehicle
Municipality °
Office Machine
Ordnance
Precious Metals and Jewelry
Printed Circuit Boards
Railroad
Ships and Boats
Stationary Industrial Equipment
312
1,356
1,861
2,289
6,275
2,003
3,208
153
33,683
3,030
879
1,506
4,342
249
403
307
617
97
273
6.217
Source: MP&M Survey Database.
a Because some sites perform operations in more than one sector, the sum of sites by sector exceeds the total number
of sites that discharge water (62,749).
bThe Job Shop Sector includes any MP&M facility that owns < 50% of the products they work on (annual area
basis). This includes metal finishing job shops, but also may include other job shops such as painting or assembly
job shops.
0 Technical surveys for these sites did not include sector information therefore they were listed separately for this
table.
In addition to description by sector, MP&M operations can also be described by
two types of activities: manufacturing and rebuilding/maintenance. For the purpose of the
MP&M regulation, EPA defines these activities below:
Manufacturing is the series of unit operations necessary to produce metal
products, and is generally performed in a production environment.
• Rebuilding/maintenance is the series of unit operations necessary to
disassemble used metal products into components, replace the
components or subassemblies or restore them to original function, and
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4.0 - Industry Description
reassemble the metal products. These operations are intended to keep
metal products in operating condition and can be performed in either a
production or a non-production environment.
70-
60-
50-
DEstimated MP&M Wastewater-
Discharging Sites
• Estimated MP&M Discharge Flow
40-
30-
20-
10-
Manufacturing and
Rebuilding/Maintenance
Manufacturing Only
Activity
Rebuilding/Maintenance Only
Source: MP&M Survey Database.
Note: There are 62,749 wastewater-discharging MP&M sites. Total wastewater flow is 122
billion gallons per year.
Figure 4-3. MP&M Wastewater-Discharging Sites and
Total Discharge Flow by Activity
Figure 4-3 summarizes the estimated number of MP&M wastewater-discharging
sites and baseline (i.e., current) total discharge flow by activity. The largest number of sites
(42,733) perform rebuilding/maintenance only and account for the smallest amount (6 percent) of
the total estimated discharge flow for the industry. The smallest number of sites (3,239) perform
both manufacturing and rebuilding/maintenance activities but represent 19 percent of the total
estimated discharge flow for the industry.
MP&M sites include direct dischargers, indirect dischargers, and those that are
both direct and indirect dischargers. A direct discharger is a site that discharges wastewater to a
surface water (e.g., river, lake, ocean). An indirect discharger is a site that discharges wastewater
to a publicly owned treatment works (POTW). For the purposes of the MP&M regulation, EPA
considers sites discharging exclusively to privately owned treatment works to be zero dischargers
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4.0 - Industry Description
that contract haul their wastewater to centralized waste treatment facilities. Figure 4-4
summarizes the number of MP&M wastewater-discharging sites and baseline total discharge
flow by discharge status. This figure shows that the majority of MP&M discharging facilities are
indirect dischargers.
DEstimated MP&M Wastewater-Discharging Sites
• Estimated MP&M Discharge Flow
Direct and Indirect
Direct
Discharge Destination
Indirect
Source: MP&M Survey Database.
Note: There are 62,749 wastewater-discharging MP&M sites. Total MP&M wastewater flow is
122 billion gallons per year.
Figure 4-4. MP&M Wastewater-Discharging Sites and
Total Discharge Flow by Discharge Status
Wastewater discharge flows from MP&M sites range from less than 100 gallons
per year to greater than 100 million gallons per year. Figure 4-5 summarizes the wastewater
discharge flow ranges for MP&M sites. As this figure shows, sites discharging more than one
million gallons per year (approximately 10 percent of the total sites) account for approximately
97 percent of the total wastewater discharge from the industry. In contrast, sites discharging less
than 100,000 gallons per year (approximately 72% of the total sites) account for less than 1% of
the overall wastewater discharge flow for the industry.
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50-|
45-
40-
35-
30-
25-
20-
48%
D Estimated MP&M Wastewater-Discharging Sites
• Estimated MP&M Discharge Flow
0-100
101-1,000 1,001-10,000
10,001- 100,001- 1,000,001- 10,000,001- >100,000,000
100,000 1,000,000 10,000,000 100,000,000
Discharge Flow Range (GPY)
4.1.4
Source: MP&M Survey Database.
Note: There are 62,749 wastewater-discharging MP&M sites. Total MP&M wastewater flow is
122 billion gallons per year.
Figure 4-5. MP&M Wastewater-Discharging Sites by Total Discharge Flow
Non-Wastewater-Discharging Sites
Based on the results of the survey, approximately 26,000 MP&M sites do not use
process water (dry sites) or use but do not discharge process water. Based on information from
the MP&M detailed surveys, site visits, and technical literature, these sites achieve zero discharge
of process wastewater in one of the following ways:
• Contract haul all process wastewater generated on site;
• Discharge process wastewater to either on-site septic systems or deep-well
injection systems;
Perform end-of-pipe treatment and reuse all process wastewater generated
on site;
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Perform either in-process or end-of-pipe evaporation to eliminate
wastewater discharges; or
• Perform in-process recirculation and recycling to eliminate wastewater
discharges.
As discussed in Section 3.0, EPA mailed surveys to 50 statistically selected sites
that were using but not discharging process water. Based on those survey responses, five of these
sites contract hauled all wastewater generated on site, eight actually discharged process
wastewater, 18 had no process wastewater discharges, and 19 were not engaged in MP&M. EPA
mailed an additional 24 surveys, selected for technical reasons, to sites which reported not
discharging process water on their screener questionnaire. Of these, 14 actually discharged
process wastewater, two had no process wastewater discharges, and eight were not engaged in
MP&M activities.
In addition to the 20 sites discussed above that do not discharge process
wastewater, 205 of the 1996 screener survey respondents reported eliminating wastewater
discharge by in-process or end-of-pipe evaporation, end-of-pipe treatment and reuse, in-process
recirculation and recycling, or other unspecified means. Figure 4-6 shows the number of sites
using each type of zero discharge method. Note that Figure 4-6 provides actual number of survey
respondents and not national estimates. EPA discusses the methods used by the 225 sites that
have eliminated wastewater discharges below.
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Unknown M ethods
12%
Other
16%
In-Process or End-Of-
Pipe Evaporation
41%
In-Process
Recirculation and
Recy cling
23%
End-Of-Pipe
Treatment and Reuse
Note: There are 225 survey sites which have eliminated wastewater discharge.
Figure 4-6. Number of Screener Survey Respondents
Utilizing Each Zero Discharge Method
In-Process or End-Of-Pipe Evaporation. Ninety-one screener survey
respondents reported discharging wastewater to either evaporators, on-site ponds, or lagoons for
evaporation of process wastewater. These sites typically performed less than 20 wastewater-
discharging unit operations. None of these sites reported recovering the process wastewater.
Sludge from the evaporation units was reported as being contract hauled for off-site disposal.
End-Of-Pipe Treatment and Reuse. Nineteen screener survey respondents
reported eliminating wastewater discharge through end-of-pipe treatment and reuse of all
wastewater generated on site. These sites typically performed less than 13 wastewater-
discharging unit operations on site. As discussed in Sections 9.0 and 14.0, EPA considered end-
of-pipe ion exchange with reuse of all wastewater generated in developing the MP&M effluent
guidelines, but determined that the technology was not appropriate for national effluent
guidelines for this industry because its effectiveness and potential metals recovery advantages
were generally limited to specific sites and specific metal types and not to the industry as a
whole.
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In-Process Recirculation and Recycling. Fifty screener survey respondents
reported eliminating wastewater discharge through in-process recirculation and recycling. Most
of these sites perform fewer than 10 wastewater-generating unit operations; five sites perform
between 10 and 20 wastewater-generating unit operations. Several sites perform heat treating
operations, in which a stagnant water quench is used and not discharged. Some sites perform
surface finishing operations (e.g., alkaline cleaning and chemical conversion coating) in stagnant
baths and do not discharge wastewater. Make-up water is added for evaporation. Based on the
data from MP&M sites, only sites with few unit operations are typically able to achieve zero
discharge solely through in-process recirculation and recycling.
Other. Thirty-seven screener survey respondents reported eliminating
wastewater discharge through a variety of other methods including land application and septic
systems.
EPA's Underground Injection Control (UIC) Program, authorized by the Safe
Drinking Water Act, regulates shallow on-site systems and deep wells that discharge fluids or
wastewater into the subsurface and thus may endanger underground sources of drinking water. If
a facility disposes any wastewater (other than solely sanitary waste) into a shallow disposal
system (e.g., septic system or a floor drain connected to a dry well) that well is covered by the
UIC program. If you think you have a UIC disposal well on your facility, you should contact
your State UIC Program authority to determine your compliance status.
EPA published the Class V Rule in the Federal Register on December 7, 1999 (64
FR 68545), which affected facilities using on-site systems to dispose waste associated with motor
vehicle service and repair in state-designated groundwater protection areas. The EPA is
scheduled to develop additional requirements for other Class V wells that receive endangering
waste. Contact your State UIC Program for more information on these developing regulations.
4.2 General Discussion of MP&M Processes
This section presents a general discussion of MP&M processes, including the
different categories of unit operations, descriptions of the unit operations performed, metal types
processed, and wastewater discharge volumes generated.
4.2.1 Types of Unit Operations Performed
MP&M sites perform a wide variety of process unit operations on metal parts,
products, and machines. The MP&M regulatory development effort initially focused on 45 unit
operations (and their associated rinses) performed at MP&M sites, plus wet air pollution control
operations. EPA describes these 46 unit operations in detail in Section 4.2.2. During the
regulatory development effort, EPA identified additional unit operations performed at MP&M
sites. Section 4.2.2 also lists these additional unit operations.
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Each of the MP&M unit operations can be listed under one of the following
types:
Metal shaping operations;
• Surface preparation operations;
Metal deposition operations;
• Organic deposition operations;
Surface finishing operations;
• Assembly operations;
Drydock operations;
• Specialized printed wiring board operations; and
Unit operations performed at Steel Forming and Finishing sites.
Metal shaping operations are mechanical operations that alter the form of raw
materials into intermediate and final products. Surface preparation operations are chemical and
mechanical operations that remove unwanted materials from or alter the chemical or physical
properties of the surface prior to subsequent MP&M operations. Metal deposition operations
apply a metal coating to the part surface by chemical or physical means. Organic deposition
operations apply an organic material to the part by chemical or physical means. Sites may
perform metal and organic deposition operations to protect the surface from wear or corrosion,
modify the electrical properties of the surface, or alter the appearance of the surface. Surface
finishing operations protect and seal the surface of the treated part from wear or corrosion by
chemical means. Sites may use some surface finishing operations to alter the appearance of the
part surface. Assembly operations are performed throughout the manufacturing, rebuilding, or
maintenance process. Drydock operations are those MP&M unit operations performed at ship
and boat facilities within dry docks or similar structures and incorporate many of the previously
described types of MP&M operations. Specialized printed wiring board operations are those
specific to the manufacture or rebuilding/maintenance of wiring boards (such as Carbon Black
Deposition, Solder Flux Cleaning, and Photo Image Developing). Additional unit operations
performed at Steel Forming and Finishing sites are defined in Section 14.1.5. Table 4-2 lists
example MP&M unit operations common to each type of operation described above.
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Table 4-2
MP&M Unit Operations Listed by Type
Type of Unit Operation
Metal Shaping
Surface Preparation
Metal Deposition
Organic Deposition
Surface Finishing
Assembly
Specialized Printed Wiring Board
Unit operations performed at Steel Forming and
Finishing sites
Example Unit
Operations Performed
Machining, Grinding, Deformation
Alkaline Cleaning, Acid Treatment
Electroplating, Vapor Deposition
Painting
Chemical Conversion Coating
Testing (e.g. leak testing), Assembly
Solder Leveling, Photo Resist Applications
Mechanical Descaling, Hot Dip Coating
At a given MP&M site, the specific unit operations performed and the sequence
of operations depend on many factors, including the activity (i.e., manufacturing, rebuilding/
maintenance), industrial sector, and type of product processed. As a result, MP&M sites perform
many different combinations and sequences of unit operations. For example, MP&M sites that
repair, rebuild or maintain products often conduct preliminary operations that may not be
performed at manufacturing facilities (e.g. disassembly, cleaning, or degreasing to remove dirt
and oil accumulated during use of the product). In general, however, MP&M products are
processed in the following order:
• The raw material (e.g., bar stock, wire, rod, sheet stock, plates) undergoes
some type of metal shaping process, such as impact or pressure
deformation, machining, or grinding. In these operations, the raw
material is shaped into intermediate forms for further processing or into
final forms for assembly and shipment to the customer. Sites typically
clean and degrease the parts between some of the shaping operations to
remove lubricants, coolants, and metal fines. Sites may also perform heat
treating operations between shaping operations to alter the physical
characteristics of the part.
• After shaping, the part typically undergoes some type of surface
preparation operation, such as alkaline cleaning, acid pickling, or barrel
finishing. The specific operation used depends on the subsequent unit
operations to be performed and the final use of the products. For
example, prior to electroplating, parts typically undergo acid pickling (i.e.,
acid cleaning) to prepare the surface of the part for electroplating. Before
assembly, parts typically undergo alkaline cleaning or barrel finishing.
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Parts undergo surface preparation operations at various stages of the
production process. Additional cleaning and degreasing steps precede
metal deposition, organic deposition, surface finishing, and assembly
operations.
• Metal and organic deposition operations typically follow shaping and
surface preparation operations, and precede surface finishing and final
assembly operations. Electroplating operations typically follow alkaline
and acid treatment operations, while painting operations typically follow
phosphate conversion coating and alkaline treatment operations.
• Surface finishing operations are typically performed after shaping and
surface preparation operations. Some surface finishing operations are
performed after metal deposition operations. For example, chromate
conversion coating typically follows acid cleaning, although this operation
is sometimes performed as a sealant operation after electroplating (e.g.
chemical conversion coating of cadmium plated parts). Some surface
finishing operations are also performed prior to organic coating
operations. For example, phosphate conversion coating frequently
precedes painting to enhance the paint adhesion.
• Disassembly operations may be performed as the first step in the
rebuilding process. Assembly operations, on the other hand, are
performed at many steps of the manufacturing and rebuilding process.
Assembly operations prepare the final product. Assembly may also
involve some final shaping (e.g., drilling and grinding) and surface
preparation (e.g., alkaline cleaning). Final assembly operations are
generally the last operations performed prior to shipment to the customer.
Some MP&M sites conduct all of these types of operations in manufacturing or
rebuilding products, while others may perform only some types. For example, a site in the
hardware sector may start with bar stock and manufacture a final hardware product, performing
machining, cleaning, electroplating, conversion coating, painting, degreasing, and assembly
operations. Another hardware site may focus on painting the parts, and only perform cleaning
and painting operations. A third hardware site may only shape the parts, and perform only
machining, cleaning, and degreasing operations.
4.2.2 MP&M Unit Operations and Rinses
This section describes each of the 46 MP&M unit operations listed in Table 4-3
and the wastewater generated from each operation and associated rinse. The following
descriptions are included for informational purposes and are not meant to supersede regulatory
definitions (e.g., definitions for unit operations that are part of the proposed rule are defined in
Section 14 in the applicable subcategory section).
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Table 4-3
Typical Unit Operations Performed at MP&M Sites
Unit Operation Name
1. Abrasive Blasting
2. Abrasive Jet Machining
3. Acid Treatment with Chromium
4. Acid Treatment without Chromium
5. Alkaline Cleaning for Oil Removal
6. Alkaline Treatment with Cyanide
7. Alkaline Treatment without Cyanide
8. Anodizing with Chromium
9. Anodizing without Chromium
10. Aqueous Degreasing
11. Assembly/Disassembly
12. Barrel Finishing
13. Burnishing
14. Chemical Conversion Coating without
Chromium
15. Chemical Milling
16. Chromate Conversion Coating
17. Corrosion Preventive Coating
18. Electrical Discharge Machining
19. Electrochemical Machining
20. Electroless Plating
21. Electrolytic Cleaning
22. Electroplating with Chromium
23. Electroplating with Cyanide
24. Electroplating without Chromium or Cyanide
25. Electropolishing
26. Floor Cleaning
27. Grinding
28. Heat Treating
29. Impact Deformation
30. Machining
31. Metal Spraying
32. Painting - Spray or Brush
33. Painting - Immersion
34. Plasma Arc Machining
35. Polishing
36. Pressure Deformation
37. Salt Bath Descaling
38. Soldering/Brazing
3 9. Solvent Degreasing
40. Stripping (paint)
41. Stripping (metallic coating)
42. Testing
43. Thermal Cutting
44. Washing Finished Products
45. Welding
46. Wet Air Pollution Control
Source: MP&M Survey database.
Abrasive Blasting involves removing surface films from a workpiece by using
abrasive directed at high velocity against the workpiece. Abrasive blasting
includes bead, grit, shot, and sand blasting, and may be performed either dry or
with water. The primary applications of wet abrasive blasting include: removing
burrs on precision parts; producing satin or matte finishes; removing fine tool
marks; and removing light mill scale, surface oxide, or welding scale. Wet
blasting can be used to finish fragile items such as electronic components. Also,
some aluminum parts are wet blasted to achieve a fine-grained matte finish for
decorative purposes. With abrasive blasting operations, the water and abrasive are
typically reused until the particle size diminishes due to impacting and fracture.
Abrasive Jet Machining includes removing stock material from a workpiece by a
high-speed stream of abrasive particles carried by a liquid or gas from a nozzle.
Abrasive jet machining is used for deburring, drilling, and cutting thin sections of
metal or composite material. Unlike abrasive blasting, this process operates at
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pressures of thousands of pounds per square inch. The liquid streams are typically
alkaline or emulsified oil solutions, although water can also be used.
Acid Treatment With Chromium is a general term used to describe any
application of an acid solution containing chromium to a metal surface. Acid
cleaning, chemical etching, and pickling are types of acid treatment.
Chromic acid is used occasionally for cleaning cast iron, stainless steel, cadmium
and aluminum, and bright dipping of copper and copper alloys. Also, chromic
acid solutions can be used as final steps in acid cleaning phosphate conversion
coating systems.
For chemical conversion coatings formulated with chromic acid, see unit
operation 16.
Wastewater generated from acid treatment includes spent solutions and rinse
waters. Spent solutions are typically batch discharged and treated or disposed of
off site. Most acid treatment operations are followed by a water rinse to remove
residual acid.
Acid Treatment Without Chromium is a general term used to describe any
application of an acid solution, not containing chromium, to a metal surface. Acid
cleaning, chemical etching, and pickling are types of acid treatment.
Wastewater generated from acid treatment includes spent solutions and rinse
waters. Spent solutions are typically batch discharged and treated or disposed of
off site. Most acid treatment operations are followed by a water rinse to remove
residual acid.
Alkaline Cleaning for Oil Removal is a general term for the application of an
alkaline cleaning agent to a metal part to remove oil and grease during the
manufacture, maintenance, or rebuilding of a metal product.
This unit operation does not include the washing of finished products after routine
use (see unit operation 44), or the application of an alkaline cleaning agent to
remove nonoily contaminants such as dirt and scale (see unit operations 6 and 7).
Wastewater generated from this operation includes spent cleaning solutions and
rinse waters.
• Alkaline cleaning is performed to remove foreign contaminants from
parts. This process is commonly applied prior to finishing operations,
such as electroplating.
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• Emulsion cleaning is an alkaline treatment (typically performed in the pH
range of 7 to 9) that uses either complex chemical enzymes or common
organic solvents (e.g., kerosene, mineral oil, glycols, and benzene)
dispersed in water with the aid of an emulsifying agent. Depending on the
solvent used, cleaning is performed at temperatures from room
temperature to 82* C (18OF). The process is often used as a replacement
for vapor degreasing.
Alkaline Treatment With Cyanide is a general term used to describe the
application of an alkaline solution containing cyanide to a metal surface to clean
it.
Wastewater generated from alkaline treatment includes spent solutions and rinse
waters. Alkaline treatment solutions become contaminated during use from the
introduction of soils and/or dissolution of the base metal, and they are typically
batch discharged for treatment or disposal. Alkaline treatment operations are
typically followed by a water rinse that is discharged to treatment. EPA does not
consider the washing of finished products after routine use to be part of this unit
operation, but instead classifies this as unit operation 44, washing of finished
products.
Alkaline Treatment Without Cyanide is a general term used to describe the
application of an alkaline solution, not containing cyanide, to a metal surface to
clean the metal surface or prepare the metal surface for further surface finishing.
Alkaline treatment includes alkaline cleaning and emulsion cleaning as described
under unit operation 5.
Anodizing With Chromium involves producing a protective oxide film on
aluminum, magnesium, or other light metal, usually by passing an electric current
through an electrolyte bath in which the metal is immersed. Anodizing may be
followed by a sealant operation.
Chromic acid anodic coatings have a relatively thick boundary layer and are more
protective than sulfuric acid coatings. For these reasons, chromic acid is
sometimes used when the part cannot be completely rinsed. These oxide coatings
provide corrosion protection, decorative surfaces, a base for painting and other
coating processes, and special electrical and mechanical properties.
Wastewater generated from anodizing includes spent anodizing solutions,
sealants, and rinse waters. Because of the anodic nature of the process, anodizing
solutions become contaminated with the base metal being processed. These
solutions eventually reach an intolerable concentration of dissolved metal and
require treatment or disposal. Rinse water following anodizing, coloring, and
sealing steps is typically discharged to treatment.
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9 Anodizing Without Chromium involves producing of a protective oxide film on
aluminum, magnesium, or other light metal, usually by passing an electric current
through an electrolyte bath in which the metal is immersed. Phosphoric acid,
sulfuric acid, and boric acid, are all types of anodizing. Anodizing may also
include sealant baths. These oxide coatings provide corrosion protection,
decorative surfaces, a base for painting and other coating processes, and special
electrical and mechanical properties.
Wastewater generated from anodizing includes spent anodizing solutions,
sealants, and rinse waters. Because of the anodic nature of the process, anodizing
solutions become contaminated with the base metal being processed. These
solutions eventually reach an intolerable concentration of dissolved metal and
require treatment or disposal. Rinse water following anodizing, coloring, and
sealing steps typically discharged to treatment.
10 Aqueous Degreasing involves cleaning metal parts using aqueous-based cleaning
chemicals primarily to remove residual oils and greases from a part. Residual oils
can be from previous operations (e.g., machine coolants), oil from product use in
a dirty environment, or oil coatings intended to inhibit corrosion. Wastewater
generated by this operation includes spent cleaning solutions and rinse waters.
11 Assembly/Disassembly involves fitting together previously manufactured or
rebuilt parts or components into a complete metal product or machine or taking a
complete metal product or machine apart. Assembly/disassembly operations are
typically dry; however, special circumstances can require water for cooling or
buoyancy. Also, rinsing may be necessary under some conditions.
12 Barrel Finishing (i.e., tumbling, mass finishing) involves polishing or deburring
a workpiece using a rotating or vibrating container and abrasive media or other
polishing materials to achieve a desired surface appearance. Parts to be finished
are placed in a rotating barrel or vibrating unit with an abrasive media (e.g.,
ceramic chips, pebbles), water, and chemical additives (e.g., alkaline detergents).
As the barrel rotates, the upper layer of the part slides toward the lower side of the
barrel, causing the abrading or polishing. Similar results can also be
accomplished in a vibrating unit, where the entire contents of the container are in
constant motion, or in a centrifugal unit, which compacts the load of media and
parts as the unit spins and generates up to 50 times the force of gravity. Spindle
finishing is a similar process, where parts to be finished are mounted on fixtures
and exposed to a rapidly moving abrasive slurry.
Wastewater generated by barrel finishing includes spent process solutions and
rinses. Following the finishing process, the contents of the barrel are unloaded.
Process wastewater is either discharged continuously during the process,
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discharged after finishing, or collected and reused. The parts are sometimes given
a final rinse to remove particles of abrasive media from part surfaces.
13 Burnishing involves finish sizing or smooth finishing a workpiece (previously
machined or ground) by displacing, rather than removing, minute surface
irregularities with smooth point or line-contact, fixed or rotating tools. Lubricants
or soap solutions can be used to cool tools used in burnishing operations.
Wastewater is generated from burnishing operations through process solution
discharges and rinsing.
14 Chemical Conversion Coating without Chromium is the process of applying a
protective coating on the surface of a metal without using chromium. Such
coatings include metal phosphates, metal coloring, passivation, or other coatings.
These coatings are applied to a base metal or previously deposited metal to
increase corrosion protection and lubricity, prepare the surface for additional
coatings, or formulate a special surface appearance. This unit operation includes
sealant operations using additives other than chromium.
• Phosphate conversion coatings are applied for one or more of the
following reasons: to provide a base for paints and other organic coatings;
to condition surfaces for cold forming operations by providing a base for
drawing compounds and lubricants; to impart corrosion resistance to the
metal surface; or to provide a suitable base for corrosion-resistant oils or
waxes. Phosphate conversion coatings are formed by immersing a metal
part in a dilute solution of phosphoric acid, phosphate salts, and other
reagents.
• Metal coloring by chemical conversion coating produces a large group of
decorative finishes. Metal coloring includes the formation of oxide
conversion coatings. In this operation, the metal surface is converted into
an oxide or similar metallic compound, giving the part the desired color.
The most common colored finishes are used on copper, steel, zinc, and
cadmium.
• Passivation forms a protective film on metals, particularly stainless steel,
by immersing parts in an acid solution. Stainless steel is passivated to
dissolve embedded iron particles and to form a thin oxide film on the
surface of the metal.
Wastewater generated by chemical conversion coating operations includes spent
process solutions and rinses (i.e., both the chemical conversion coating solutions
and post-treatment sealant solutions). These solutions are commonly discharged
to treatment when contaminated with the base metal or other impurities. Rinsing
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normally follows each process step, except after some sealants, which dry on the
part surface.
15 Chemical Milling (or Chemical Machining) involves removing metal from a
workpiece by controlled chemical attack, or etching, to produce desired shapes
and dimensions. In chemical machining, a masking agent is typically applied to
cover a portion of the part's surface; the exposed (unmasked) surface is then
treated with the chemical machining solution.
Wastewater generated by chemical machining operations includes spent process
solutions and rinses. Process solutions are commonly discharged after becoming
contaminated with the base metal. Rinsing normally follows chemical machining.
16 Chromate Conversion Coating (or chromating) involves forming a conversion
coating (protective coating) on a metal by immersing or spraying the metal with a
hexavalent chromium compound solution to produce a hexavalent and/or trivalent
chromium compound coating. This is also known as chromate treatment, and is
most often applied to aluminum, zinc, cadmium or magnesium surfaces. Sealant
operations using chromium are also included in this unit operation.
Chromate solutions include two types: (1) those that deposit substantial chromate
films on the substrate metal and are complete treatments themselves, and (2) those
that seal or supplement oxide, phosphate, or other types of protective coatings.
Wastewater generated by chromate conversion coating operations includes spent
process solutions (i.e., both the chromate conversion coating solutions and post-
treatment sealant solutions) and rinses. These solutions are commonly discharged
to treatment when contaminated with the base metal or other impurities. Also,
chromium-based solutions, which are typically formulated with hexavalent
chromium, lose operating strength when the hexavalent chromium reduces to
trivalent chromium during use. Rinsing normally follows each process step,
except after some sealants, which dry on the surface of the part.
17 Corrosion Preventive Coating involves applying removable oily or organic
solutions to protect metal surfaces against corrosive environments. Corrosion
preventive coatings include, but are not limited to: petrolatum compounds, oils,
hard dry-film compounds, solvent-cutback petroleum-based compounds,
emulsions, water-displacing polar compounds, and fingerprint removers and
neutralizers. Corrosion preventive coating does not include electroplating or
chemical conversion coating (including phosphate conversion coating) operations.
Many corrosion preventive materials are also formulated to function as lubricants
or as a base for paint. Typical applications include: assembled machinery or
equipment in standby storage; finished parts in stock or spare parts for
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replacement; tools such as drills, taps, dies, and gauges; and mill products such as
sheet, strip, rod and bar.
Wastewater generated from corrosion preventive coating operations includes
spent process solutions and rinses. Process solutions are discharged when they
become contaminated with impurities or are depleted of constituents. Corrosion
preventive coatings do not typically require an associated rinse, but parts are
sometimes rinsed to remove the coating before further processing.
18 Electrical Discharge Machining involves removing metals by a rapid spark
discharge between different polarity electrodes, one the workpiece and the other
the tool, separated by a small gap. The gap may be filled with air or a dielectric
fluid. This operation is used primarily to cut tool alloys, hard nonferrous alloys,
and other hard-to-machine materials. Most electrical discharge machining
processes are operated dry. In some cases, water is used in the process, which
generates wastewater of water-based dielectric fluids.
19 Electrochemical Machining is a process in which the workpiece becomes the
anode and a shaped cathode is the cutting tool. By pumping electrolyte between
the electrodes and applying a potential, metal is rapidly but selectively dissolved
from the workpiece. Wastewater generated by electrochemical machining
includes spent electrolytes and rinses.
20 Electroless Plating involves deposition of a metallic coating by a controlled
chemical reduction that is catalyzed by the substitute material being deposited
without using an electrical current. The metal to be plated onto a part is typically
held in solution at high concentrations by the use of a chelating agent. This
operation plates all areas of the part to a uniform thickness regardless of the
configuration of the part. Also, an electroless-plated surface is dense and virtually
nonporous. Copper and nickel electroless plating are the most common.
Sealant operations (i.e., other than hot water dips) performed following this
operation are considered separate unit operations if they include any additives.
Wastewater generated from electroless plating operations includes spent process
solutions and rinses. This wastewater contain chelated metals, which require
separate preliminary treatment to break the metal chelates prior to conventional
chemical precipitation. Rinsing follows most electroless plating processes to
remove residual plating solution and prevent contamination of subsequent process
baths.
21 Electrolytic Cleaning involves removing soil, scale, or surface oxides from a
workpiece by electrolysis. The workpiece is one of the electrodes and the
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electrolyte is usually alkaline. Electrolytic alkaline cleaning and electrolytic acid
cleaning are the two types of electrolytic cleaning. They are described below.
Electrolytic alkaline cleaning produces a cleaner surface than
nonelectrolytic methods of alkaline cleaning. This method uses strong
agitation, gas evolution in the solution, and oxidation-reduction reactions
that occur during electrolysis. In addition, dirt particles become
electrically charged and are repelled from the part surface.
• Electrolytic acid cleaning is sometimes used as a final cleaning before
electroplating. Sulfuric acid is most frequently used as the electrolyte. As
with electrolytic alkaline cleaning, the mechanical scrubbing effect from
the evolution of gas enhances the effectiveness of the process.
Wastewater generated from electrolytic cleaning operations includes spent process
solutions and rinses. Electrolytic cleaning solutions become contaminated during
use due to the base metal dissolving and the introduction of contaminants. The
solution is typically batch discharged for treatment or disposal after it weakens.
Following electrolytic cleaning, rinsing is used to remove residual cleaner and
prevent the contamination of subsequent process baths.
22 Electroplating with Chromium involves producing a chromium metal coating
on a surface by electrodeposition. Electroplating provides corrosion protection,
wear or erosion resistance, lubricity, electrical conductivity, or decoration.
In electroplating, metal ions in acid, alkaline, or neutral solutions are reduced on
the cathodic surfaces of the parts being plated. Metal salts or oxides are typically
added to replenish solutions. Chromium trioxide is often added as a source of
chromium.
In addition to water and the metal being deposited, electroplating solutions often
contain agents that form complexes with the metal being deposited, stabilizers to
prevent hydrolysis, buffers for pH control, catalysts to assist in deposition,
chemical aids to dissolve anodes, and miscellaneous ingredients that modify the
process to attain specific properties. Sealant operations (i.e., other than hot water
dips) performed after this operation are considered separate unit operations if they
include any additives.
Wastewater generated from electroplating operations includes spent process
solutions and rinses. Electroplating solutions occasionally become contaminated
during use due to the base metal dissolving and/or the introduction of other
contaminants. As this happens, the performance of the electroplating solutions
diminishes. Spent concentrated solutions are typically treated for contaminant
removal and reused, processed in a wastewater treatment system, or sent off site
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4.0 - Industry Description
for disposal. Rinse waters, including some drag-out rinse tank solutions, are
typically treated on site.
23 Electroplating with Cyanide involves producing metal coatings on a surface by
electrodeposition, using cyanide. Electroplating provides corrosion protection,
wear or erosion resistance, lubricity, electrical conductivity, or decoration.
In electroplating, metal ions in acid, alkaline, or neutral solutions are reduced on
the cathodic surfaces of the parts being plated. The metal ions in solution are
typically replenished by dissolving metal from anodes contained in inert wire or
metal baskets. Sealant operations performed after this operation are considered
separate unit operations if they include any additives (i.e., any sealant operations
other than hot water dips).
In addition to water and the metal being deposited, electroplating solutions often
contain agents that form complexes with the metal being deposited, stabilizers to
prevent hydrolysis, buffers for pH control, catalysts to assist in deposition,
chemical aids for dissolving anodes, and miscellaneous ingredients that modify
the process to attain specific properties. Cyanide, usually in the form of sodium
or potassium cyanide, is frequently used as a complexing agent for zinc, cadmium,
copper, and precious metal baths.
Wastewater generated from electroplating operations includes spent process
solutions and rinses. Electroplating solutions occasionally become contaminated
during use due to dissolution of the base metal and/or the introduction of other
contaminants. As this happens, the performance of the electroplating solutions
diminishes. Spent concentrated solutions are typically treated for contaminant
removal and reused, processed in a wastewater treatment system, or sent off site
for disposal. Rinse waters, including some drag-out rinse tank solutions, are
typically treated on site.
24 Electroplating without Chromium or Cyanide involves the production of metal
coatings on a surface by electrodeposition, without the use of chromium or
cyanide. Commonly electroplated metals include nickel, copper, tin/lead, gold,
and zinc. Electroplating is performed to provide corrosion protection, wear or
erosion resistance, lubricity, electrical conductivity, or decoration.
In electroplating, metal ions in acid, alkaline, or neutral solutions are reduced on
the cathodic surfaces of the parts being plated. The metal ions in solution are
typically replenished by dissolving metal from anodes contained in inert wire or
metal baskets. Sealant operations performed after this operation are considered
separate unit operations if they include any additives (i.e., any sealant operations
other than hot water dips).
4-22
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In addition to water and the metal being deposited, electroplating solutions often
contain agents that form complexes with the metal being deposited, stabilizers to
prevent hydrolysis, buffers for pH control, catalysts to assist in deposition,
chemical aids for dissolving anodes, and miscellaneous ingredients that modify
the process to attain specific properties.
Wastewater generated from electroplating operations includes spent process
solutions and rinses. Electroplating solutions occasionally become contaminated
during use due to dissolution of the base metal and/or the introduction of other
contaminants. As this happens, the performance of the electroplating solutions
diminishes. Spent concentrated solutions are typically treated for contaminant
removal and reused, processed in a wastewater treatment system, or sent off site
for disposal. Rinse waters, including some drag-out rinse tank solutions, are
typically treated on site.
25 Electropolishing involves producing a highly polished surface on a workpiece
using reversed electrodeposition in which the anode (workpiece) releases some
metal ions into the electrolyte to reduce surface roughness. When current is
applied, a polarized film forms on the metal surface, through which metal ions
diffuse. In this process, areas of surface roughness on parts serve as high-current
density areas and are dissolved at rates greater than the smoother portions of the
metal surface.
Metals are electropolished to improve appearance, reflectivity, and corrosion
resistance. Base metals processed by electropolishing include aluminum, copper,
zinc, low-alloy steel, and stainless steel. Common electrolytes include sodium
hydroxide and combinations of sulfuric acid, phosphoric acid, and chromic acid.
Wastewater generated from electropolishing operations includes spent process
solutions and rinses. Eventually, the concentration of dissolved metals increases
beyond tolerable levels and the process becomes ineffective. Typically, a portion
of the bath is decanted and some fresh chemicals are added, or the entire solution
is discharged to treatment and replaced with fresh chemicals. Rinsing can involve
several steps and can include hot immersion or spray rinses.
26 Floor Cleaning (in process area) removes dirt, debris, process solution spills,
etc., from process area floors. Floors can be cleaned using wet or dry methods,
such as vacuuming, mopping, dry sweeping, and hose rinsing. Nonprocess area
floor cleaning in offices and other areas is not included in this unit operation.
27 Grinding involves removing stock from a workpiece by using abrasive grains
held by a rigid or semirigid binder. Grinding shapes or deburrs the workpiece.
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4.0 - Industry Description
The grinding tool is usually a disk (the basic shape of grinding wheels), but can
also be a cylinder, ring, cup, stick, strip, or belt. The most commonly used
abrasives are aluminum oxide, silicon carbide, and diamond. The process may
use a grinding fluid to cool the part and remove debris or metal fines.
Wastewater generated from grinding operations includes spent coolants and
rinses. Metal-working fluids become spent for a number of reasons, including
increased biological activity (i.e., the fluids become rancid) or decomposition of
the coolant additives. Rinse waters are typically assimilated into the working
fluid or treated on site.
28 Heat Treating involves modifying the physical properties of a workpiece by
applying controlled heating and cooling cycles. This operation includes temper-
ing, carburizing, cyaniding, nitriding, annealing, aging, normalizing, austenitizing,
austempering, siliconizing, martempering, and malleablizing. Parts are heated in
furnaces or molten salt baths, and then may be cooled by quenching in aqueous
solutions (e.g., brine solutions), neat oils (pure oils with little or no impurities), or
oil/water emulsions. Heat treating is typically a dry operation. It is considered a
wet operation if aqueous quenching solutions are used. Wastewater can be
generated from spent quench water and rinses.
29 Impact Deformation involves applying impact force to a workpiece to
permanently deform or shape it. Impact deformation may include mechanical
operations such as hammer forging, shot peening, peening, coining, high-energy-
rate forming, heading, or stamping.
Impact deformation operations use natural and synthetic oils, light greases, and
pigmented lubricants. Pigmented lubricants include whiting, lithapone, mica, zinc
oxide, molybdenum disulfide, bentonite, flour, graphite, white lead, and soap-like
materials.
These operations are typically dry, but wastewater can be generated from lubricant
discharge and from rinsing operations associated with the process.
30 Machining involves removing stock from a workpiece (as chips) by forcing a
cutting tool against the workpiece. This definition includes machining operations
such as turning, milling, drilling, boring, tapping, planing, broaching, sawing,
cutoff, shaving, shearing, threading, reaming, shaping, slotting, hobbing, and
chamfering. Machining operations use various types of metal working fluids, the
choice of which depends on the type of machining being performed and the
preference of the machine shop. The fluids can be categorized into four groups:
straight oil (neat oils), synthetic, semi synthetic, and water-soluble oil.
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Machining operations generate wastewater from working fluid or rinse water
discharge. Metal working fluids are periodically discarded because of reduced
performance or development of a rancid odor. After machining, parts are
sometimes rinsed to remove coolant and metal chips. The coolant reservoir is
sometimes rinsed, and the rinse water is added to the working fluid.
31 Metal Spraying (including water curtain) involves applying a metallic coating
to a workpiece by projecting molten or semimolten metal particles onto a
substrate. Coatings can be sprayed from rod or wire stock or from powdered
material. The process involves feeding the material (e.g., wire) into a flame where
it is melted. The molten stock is then stripped from the end of the wire and
atomized by a high-velocity stream of compressed air or other gas, which propels
the material onto a prepared substrate or part.
Metal spraying coatings are used in a wide range of special applications,
including: insulating layers in applications such as induction heating coils;
electromagnetic interference shielding; thermal barriers for rocket engines;
nuclear moderators; films for hot isostatic pressing; and dimensional restoration
of worn parts.
Metal spraying is sometimes performed in front of a "water curtain" (a circulated
water stream used to trap overspray) or a dry filter exhaust hood that captures the
overspray and fumes. With water curtain systems, water is recirculated from a
sump or tank. Wastewater is generated when the sump or tank is periodically
discharged. Metal spraying is not typically followed by rinsing.
32 Painting-Spray or Brush (including water curtains) involves applying an
organic coating to a workpiece. The application of coatings such as paint,
varnish, lacquer, shellac and plastics uses processes such as spraying, brushing,
roll coating, lithographing, powder coating, and wiping.
Water is used in painting operations as a solvent (water-borne formulations) for
rinsing, for cleanup, and for water-wash (or curtain) type spray booths. Paint
spray booths typically use most of the water in this unit operation. Spray booths
capture overspray (i.e., paint that misses the product during application), and
control the introduction of contaminants to the workplace and environment.
33 Painting-Immersion (including electrophoretic, "e-coat") involves applying an
organic coating to a workpiece using technology-based processes such
autophoretic and electrophoretic painting, described below.
• Autophoretic Painting is the application by nonelectrophoresis of an
organic paint film when a workpiece is immersed in a suitable aqueous
bath.
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Electrophoretic Painting is coating a workpiece by making it either
anodic or cathodic in a bath that is generally an aqueous emulsion of the
organic coating material.
• Other Immersion Painting includes all other types of immersion painting
such as dip painting.
Water is used in immersion paint operations as a carrier for paint particles and to
rinse the part. Aqueous painting solutions and rinses are typically treated through
an ultrafiltration system. The concentrate is returned to the painting solution, and
the permeate is reused as rinse water. Sites typically discharge a bleed stream to
treatment. The painting solution and rinses are periodically batch-discharged to
treatment.
34 Plasma Arc Machining involves material removal or shaping of a workpiece by a
high-velocity jet of high-temperature, ionized gas. In plasma arc machining, a gas
(nitrogen, argon, or hydrogen) is passed through an electric arc, causing the gas to
become ionized, and heated to temperatures exceeding 16,650* C (30,000* F). The
relatively narrow plasma jet melts and displaces the material in its path. Because
plasma machining does not depend on a chemical reaction between the gas and
the part, and because plasma temperatures are extremely high, the process can be
used on almost any metal, including those that are resistant to oxygen-fuel gas
cutting. The method is used mainly for profile cutting of stainless steel and
aluminum alloys.
Although plasma arc machining is typically a dry process, water is used for water
injection plasma arc torches. In these cases, a constricted swirling flow of water
surrounds the cutting arc. This operation may also be performed immersed in a
water bath. In both cases, the water is used to stabilize the arc, to cool the part,
and to contain smoke and fumes.
35 Polishing involves removing stock from a workpiece by the action of loose or
loosely held abrasive grains carried to the workpiece by a flexible support.
Usually, the amount of stock removed in a polishing operation is only incidental
to achieving a desired surface finish or appearance. Buffing is included in the
polishing unit operation. It is usually performed using a revolving cloth or sisal
buffing wheel, which is coated with a suitable compound. Liquid buffing
compounds are used extensively for large-volume production on semiautomated
or automated buffing equipment. Polishing operations are typically dry, although
some operations are performed with liquid compounds or associated rinses.
36 Pressure Deformation involves applying force (other than impact force) to
permanently deform or shape a workpiece. Pressure deformation operations may
4-26
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4.0 - Industry Description
include operations such as rolling, drawing, bending, embossing, sizing,
extruding, squeezing, spinning, necking, forming, crimping or flaring.
Natural and synthetic oils, light greases, and pigmented lubricants are used in
pressure deformation operations. Pigmented lubricants include whiting,
lithapone, mica, zinc oxide, molybdenum disulfide, bentonite, flour, graphite,
white lead, and soap-like materials.
Pressure deformation is typically dry, but wastewater is sometimes generated from
the discharge of lubricants or from rinsing operations associated with the process.
37 Salt Bath Descaling involves removing surface oxides or scale from a workpiece
by immersion of the workpiece in a molten salt bath or hot salt solution. Salt bath
descaling solutions can contain molten salts, caustic soda, sodium hydride, and
chemical additives. Molten salt baths are used in a salt bath-water quench-acid
dip sequence to remove oxides from stainless steel and other corrosion-resistant
alloys. In this process, the part is typically immersed in the molten salt, quenched
with water, and then dipped in acid. Oxidizing, reducing, or electrolytic salt baths
can be used depending upon the oxide to be removed. Wastewater generated from
salt bath descaling operations includes spent process solutions, quenches, and
rinses.
38 Soldering involves joining metals by inserting a thin (capillary thickness) layer of
nonferrous filler metal into the space between them. Bonding results from the
intimate contact produced by the metallic bond formed between the substrate
metal and the solder alloy. The term soldering is used where the melting temper-
ature of the filler is below 425* C (800* F). Some soldering operations use a
solder flux, which is an aqueous or nonaqueous material used to dissolve, remove,
or prevent the formation of surface oxides on the part.
Except for the use of aqueous fluxes, soldering is typically a dry operation;
however, a quench or rinse sometimes follows soldering to cool the part or
remove excess flux or other foreign material from its surface. Recent
developments in soldering technology have focused on fluxless solders and fluxes
that can be cleaned off with water.
39 Solvent Degreasing removes oils and grease from the surface of a part by using
organic solvents, including aliphatic petroleum (e.g., kerosene, naphtha),
aromatics (e.g., benzene, toluene), oxygenated hydrocarbons (e.g., ketones,
alcohol, ether), and halogenated hydrocarbons (e.g., 1,1,1-trichloroethane,
trichloroethylene, methylene chloride).
Solvent cleaning can be accomplished in either the liquid or vapor phase. Solvent
vapor degreasing is normally quicker than solvent liquid degreasing. However,
4-27
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4.0 - Industry Description
ultrasonic vibration is sometimes used with liquid solvents to decrease the
required immersion time with complex shapes. Solvent cleaning is often used as
a precleaning operation prior to alkaline cleaning, as a final cleaning of precision
parts, or as a surface preparation for some painting operations. Solvent
degreasing operations are typically not followed by rinsing, although rinsing is
performed in some cases.
40 Stripping (paint) involves removal of a paint (or other organic) coating from a
metal basis material. Stripping is commonly performed as part of the
manufacturing process to recover parts that have been improperly coated or as a
part of maintenance and rebuilding to restore parts to a usable condition.
Organic coatings (including paint) are stripped using thermal, mechanical, and
chemical means. Thermal methods include burn-off ovens, fluidized beds of
sand, and molten salt baths. Mechanical methods include scraping and abrasive
blasting (see unit operation 1). Chemical paint strippers include alkali solutions,
acid solutions, and solvents (e.g., methylene chloride).
Wastewater generated from organic coating stripping operations includes process
solutions (limited mostly to chemical paint strippers and rinses).
41 Stripping (metallic coating) involves removing a metallic coating from a metal
basis material. Stripping is commonly performed as part of the manufacturing
process to recover parts that have been improperly coated or as a part of
maintenance and rebuilding to restore parts to a usable condition.
Metallic coating stripping most often uses chemical baths, although mechanical
means (e.g., grinding, abrasive blasting) are also used. Chemical stripping is
frequently performed as an aqueous electrolytic process.
Wastewater generated from metallic coating stripping operations includes process
solutions and rinses. Stripping solutions become contaminated due to dissolution
of the base metal. Typically, the entire solution is discharged to treatment.
Rinsing is used to remove the corrosive film remaining on the parts.
42 Testing involves application of thermal, electrical, mechanical, hydraulic, or other
energy to determine the suitability or functionality of a part, assembly or complete
unit. Testing may also include the application of surface penetrant dyes to detect
surface imperfections. Other types of tests frequently performed, which are
typically dry but may generate wastewater under certain circumstances, include
electrical testing, performance testing, X-ray testing, and ultrasonic testing.
Testing is usually performed to replicate some aspect of the working environment.
Wastewater generated from testing operations includes spent process solutions
and rinses.
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43 Thermal Cutting involves cutting, slotting or piercing a workpiece using an oxy-
acetylene oxygen lance, electric arc cutting tool, or laser. Thermal cutting is
typically a dry process, except for the use of contact cooling waters and rinses.
44 Washing (finished products) involves the cleaning of finished metal products
after use or storage. This includes the use of fresh water or water containing a
mild cleaning solution. This unit operation applies only to the finished products
that do not require maintenance or rebuilding.
45 Welding involves joining two or more pieces of material by applying heat,
pressure, or both, with or without filler material, to produce a metallurgical bond
through fusion or recrystallization across the interface. Included in this definition
are gas welding, resistance welding, arc welding, cold welding, electron beam
welding, and laser beam welding. Welding is typically a dry process, except for
the occasional use of contact cooling waters or rinses.
46 Wet Air Pollution Control involves the use of water to remove chemicals,
fumes, or dusts that are entrained in air streams exhausted from process tanks or
production areas. Most frequently, wet air pollution control devices are applied to
electroplating, cleaning, and coating processes. A common type of wet air
pollution control is the wet packed scrubber consisting of a spray chamber that is
filled with packing material. Water is continuously sprayed onto the packing and
the air stream is pulled through the packing by a fan. Contaminants in the air
stream are absorbed by the water droplets and the air is released to the
atmosphere. A single scrubber often serves numerous process tanks; however, the
air streams are typically segregated by source into chromium, cyanide, and
acid/alkaline sources.
Table 4-4 lists the less common unit operations identified from MP&M detailed
surveys. Descriptions of these unit operations are contained in the public record for this
rulemaking. Wastewater discharge flow from these operations represents less than 3 percent of
the industry flow. Descriptions of unit operations applicable to the Steel Forming and Finishing
Subcategory are listed in Section 14.1.5.
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4.0 - Industry Description
Table 4-4
Additional Water-Using Unit Operations Performed at MP&M Sites
Unit Operation Name a
Acid Pickling Neutralization
Adhesive Bonding
Bilge Water
Calibration
Carbon Black Deposition
Chromium Drag-out Reduction
Cyanide Rinsing
Dry Dock/Stormwater
Galvanizing/Hot Dip Coating
Hot Dip Coating
Kerfing
Laundering
Number of
Facilities
Performing
Unit Operation
35
101
13
33
73
6
13
21
93
63
15
75
Unit Operation Name a
Mechanical Plating
Multiple Unit Operation Rinse
Phosphor Deposition
Photo Image Developing
Photo Imaging
Photo Resist Applications
Solder Flux Cleaning
Solder Fusing
Steam Cleaning
Thermal Infusion
Vacuum Impregnation
Water Shedder
Number of
Facilities
Performing
Unit Operation
127
462
7
688
7
20
248
144
22
37
51
12
Source: MP&M Survey database.
aEPA identified these unit operations based on responses to the 1989 and 1996 detailed survey mailouts.
4.2.3
Metal Types Processed
MP&M sites perform unit operations on a variety of metal types. Survey results
identified 29 different metal types that are processed at MP&M sites. Of these, iron, aluminum,
and copper are the base metals most frequently processed. Nickel, tin, lead, gold, and zinc are
frequently processed as metals electroplated onto base metals.
Many MP&M sites also process more than one metal type on site. Figure 4-7
shows the percent of wastewater-discharging sites by number of metal types processed. As
shown in Figure 4-7, more than half of the wastewater-discharging MP&M sites process more
than one metal type on site.
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4.0 - Industry Description
Five orMore Metal Types
Four Metal Types
Three MetalTypes
Zero MetalTypes
Two MetalTypes
One MetalType
4.2.4
Source: MP&M Survey Database.
Note: There are 62,749 wastewater - discharging MP&M sites. Zero metal types represent sites
discharging process water only from floor cleaning of the metals processing area.
Figure 4-7. Number of MP&M Wastewater-Discharging Sites
by Number of Metal Types Processed
Wastewater Discharge Volumes Generated
Process wastewater is used in many of the unit operations listed in Section 4.2.2.
Some operations may be performed with and without water (wet or dry) depending on the
purpose of the operation, raw materials, and final product use. For example, some machining
operations (e.g., drilling) can often be performed without a coolant, while other machining
operations (e.g., milling) typically require a coolant. Process wastewater may be recirculated,
recycled or reused by one of the zero-wastewater-discharge methods described in Section 4.1.4,
however, process wastewater is generally discharged to treatment or disposal.
Based on survey results, the most commonly performed wet unit operations are
floor cleaning and acid treatment. Survey results also show the most commonly performed unit
operations are not the ones generating the largest volumes of wastewater. Of the wastewater
discharged, 79 percent is generated from associated rinses, with chemical conversion coating
rinsing, acid treatment rinsing, and alkaline treatment rinsing generating the most wastewater.
Table 4-5 summarizes which operations are typically performed without water, the number of
MP&M sites that discharge process wastewater from each unit operation, and the total industry
discharge flow from each unit operation.
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Table 4-5
Number of MP&M Sites Discharging Process Wastewater
by Unit Operation and Flow3
Survey Unit
Operation
Number
1
1R.
2
3
3R.
4
4R.
5
5R.
6
6R.
7
7R.
8
8R.
9
9R.
10
10R.
11
11R.
12
12R.
13
13R.
Unit Operation Description
Abrasive Blasting
Abrasive Blasting Rinse
Abrasive Jet Machining
Acid Treatment With Chromium
Acid Treatment With Chromium
Rinse
Acid Treatment Without
Chromium
Acid Treatment Without
Chromium Rinse
Alkaline Cleaning for Oil Removal
Alkaline Cleaning for Oil Removal
Rinse
Alkaline Treatment With Cyanide
Alkaline Treatment With Cyanide
Rinse
Alkaline Treatment Without
Cyanide
Alkaline Treatment Without
Cyanide Rinse
Anodizing With Chromium
Anodizing With Chromium Rinse
Anodizing Without Chromium
Anodizing Without Chromium
Rinse
Aqueous Degreasing
Aqueous Degreasing Rinse
Assembly /Disassembly
Assembly /Disassembly Rinse
Barrel Finishing
Barrel Finishing Rinse
Burnishing
Burnishing Rinse
Typically
Performed
Dry
•
•
•
Estimated Number of
MP&M Sites
Discharging
Wastewater from Unit
Operation
609
667
1,072
351
429
5,690
6,574
6,253
4,400
204
252
5,667
4,185
183
194
577
678
19,148
13,718
960
836
6,639
2,820
2,311
1,447
Total Estimated Industry
Discharge Flow from Unit
Operationb
(gpy)
38,778,160
305,528,295
39,977,953
4,086,562
364,766,772
416,840,116
17,754,706,129
1,401,562,927
8,625,499,609
4,729,476
74,087,698
556,356,897
7,906,960,561
398,976
205,226,036
12,858,977
4,120,542,720
637,940,485
631,789,542
62,328,594
2,086,711
1,481,495,528
596,393,341
137,710,275
333,474,479
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4.0 - Industry Description
Table 4-5 (Continued)
Survey Unit
Operation
Number
14
14R.
15
15R.
16
16R.
17
17R.
18
18R
19
19R.
20
20R.
21
21R.
22
22R.
23
23R.
24
24R.
25
25R.
26
26R.
27
27R.
28
28R.
Unit Operation Description
Chemical Conversion Coating
Without Chromium
Chemical Conversion Coating
Without Chromium Rinse
Chemical Milling
Chemical Milling Rinse
Chromate Conversion Coating
Chromate Conversion Coating
Rinse
Corrosion Preventive Coating
Corrosion Preventive Coating
Rinse
electrical Discharge Machining
electrical Discharge Machining
Rinse
electrochemical Machining
electrochemical Machining Rinse
electroless Plating
electroless Plating Rinse
electrolytic Cleaning
electrolytic Cleaning Rinse
electroplating With Chromium
electroplating With Chromium
Rinse
electroplating With Cyanide
electroplating With Cyanide Rinse
electroplating Without Chromium
or Cyanide
electroplating Without Chromium
or Cyanide Rinse
electropolishing
electropolishing Rinse
"loor Cleaning
"loor Cleaning Rinse
Grinding
Grinding Rinse
Seat Treating
Seat Treating Rinse
Typically
Performed
Dry
•
•
Estimated Number of
MP&M Sites
Discharging
Wastewater from Unit
Operation
4,387
4,815
726
1,258
1,900
2,115
924
463
729
279
189
165
1,256
1,646
2,405
2,771
557
825
731
3,185
1,866
4,258
255
253
33,326
1,618
2,193
217
789
612
Total Estimated Industry
Discharge Flow from Unit
Operationb
(gpy)
1,231,117,839
25,297,218,112
43,500,663
1,095,828,156
73,476,786
2,146,579,879
69,973,819
686,365,140
1,714,162
3,368,478
349,183,003
43,572,599
18,175,581
665,900,951
83,645,332
3,346,961,012
30,135,241
1,543,347,451
87,597,962
856,518,170
54,401,114
3,791,840,777
4,485,954
312,554,885
3,559,210,563
46,759,620
202,036,389
2,831,300,319
196,798,353
1,804,100,965
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4.0 - Industry Description
Survey Unit
Operation
Number
29
29R.
30
30R.
31
32
32R.
33
33R.
34
35
35R.
36
36R.
37
37R.
38
38R.
39
39R.
40
40R.
41
41R.
42
42R.
43
43R.
44
44R.
45
45R.
46
Unit Operation Description
Impact Deformation
Impact Deformation Rinse
vlachining
vlachining Rinse
Vletal Spraying
Mnting - Spray or Brush
Mnting - Spray or Brush Rinse
Mnting - Immersion
-'ainting - Immersion Rinse
-'lasma Arc Machining
3olishing
-'olishing Rinse
3ressure Deformation
3ressure Deformation Rinse
salt Bath Descaling
salt Bath Descaling Rinse
soldering/Brazing
soldering/Brazing Rinse
solvent Degreasing0
solvent Degreasing Rinse
stripping (Paint)
stripping (Paint) Rinse
stripping (Metallic Coating)
stripping (Metallic Coating) Rinse
resting
resting Rinse
rhermal Cutting
rhermal Cutting Rinse
Washing Finished Products
Washing Finished Products Rinse
Welding
Welding Rinse
Wet Air Pollution Control
Typically
Performed
Dry
•
•
•
•
•
•
•
•
Estimated Number of
MP&M Sites
Discharging
Wastewater from Unit
Operation
196
75
3,156
297
52
1,117
178
271
211
458
540
491
287
92
48
67
663
1,966
106
433
1,089
1,573
1,081
1,447
2,351
591
124
3
16,862
2,798
530
194
2.290
Total Estimated Industry
Discharge Flow from Unit
Operation1"
(gpy)
46,225,701
8,976,240
735,611,690
76,349,552
186,019
1,349,687,217
1,632,505,169
237,430,089
165,435,138
11,893,377
96,480,600
1,687,785,986
268,653,304
1,105,233,854
62,902
56,171,145
425,693,444
264,719,840
327,960
36,576,913
82,557,395
796,054,566
7,415,225
1,266,477,035
4,183,822,841
138,207,480
104,662,316
28
2,563,540,125
703,810,287
1,180,762,371
61,351,089
3.332.852.389
Source: MP&M Survey Database
a MP&M Survey information was used to generate these estimated industry flows and site counts.
b These totals do not include sites generating process wastewater that is contract hauled off site or not discharged.
0 Solvent degreasing operations reported as using process water are included under alkaline treatment (see unit
operation #5).
4-34
-------
4.0 - Industry Description
4.3 Trends in the Industry
For the development of the MP&M rule, EPA collected data from the MP&M
industry for over 10 years, including detailed surveys in 1990 and 1996. Survey data and
industry site visits and sampling have shown numerous changes in the industry between 1990 and
1996. A greater number of facilities now have some type of wastewater treatment system in
place. Survey data show a 30 percent industry increase in treatment systems between 1990 and
1996. Many sites have also begun to implement advanced treatment systems that include
ultrafiltration for increased organics removal and microfiltration units to improve clarification.
The MP&M survey database indicates that (in 1990) 260 of the facilities with wastewater
treatment in place are currently using membrane filtration. By 1996, that number increased to
700. In addition, sites are moving toward greater implementation of pollution prevention and
water reduction, including progression to zero discharge when possible. Fifty-three percent
currently have in-process pollution prevention or water use reduction practices in place, and over
27 percent of discharging sites report having wet unit operations with zero discharge.
Improvements in treatment controls are allowing for more automated process controls. This
leads to more consistent wastewater treatment. Advances in wastewater treatment chemicals are
also improving treatment efficiencies.
4.4 References
1. Cubberly, William H. (ed.). Tool and Manufacturing Engineers Handbook, Desk
Edition, Society of Manufacturing Engineers, Dearborne, MI, 1989.
2. Detrisac, M. Arthur. "Treatable Cleaners," Metal Finishing. September 1991.
3. U.S. Environmental Protection Agency. Development Document for Effluent
Limitations Guidelines and Standards for the Metal Finishing Point Source
Category. EPA 440/1-83/091, June 1983.
4. Mohler, J.B. "Alkaline Cleaning for Electroplating," Metal Finishing. September
1984.
5. Wood, William G. (Coordinator). The New Metals Handbook, Vol. 5. Surface
Cleaning, Finishing, and Coating. American Society for Metals, May 1990.
6. Lowenheim, Frederick A. Electroplating Fundamentals of Surface Finishing,
McGraw-Hill Book Company, New York, NY, 1978.
7. Murphy, Michael (ed.). Metal Finishing Guidebook and Directory Issue '93,
Metal Finishing. January 1993.
4-35
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5.0 - Wastewater Characteristics
5.0 WASTEWATER CHARACTERISTICS
This section summarizes the characteristics of wastewater generated from MP&M
unit operations and raw wastewater entering wastewater treatment systems at MP&M facilities.
EPA classified wastewater generated from MP&M unit operations into the following types based
on composition and treatment requirements:
• Hexavalent chromium-bearing wastewater;
Cyanide-bearing wastewater;
Oil- and organic pollutant-bearing wastewater;
• Chelated metal-bearing wastewater; and
• General metal-bearing wastewater.
Sections 5.1 through 5.5 summarize the unit operations generating each type of
wastewater and the analytical data obtained from sampled MP&M unit operations and wastewater
treatment influent streams. For each pollutant analyzed, EPA lists the number of samples analyzed,
the number of times EPA detected the pollutant, and the minimum, maximum, mean, and median
detected concentrations. EPA obtained analytical data for unit operations and wastewater
treatment systems from the MP&M sampling program. EPA obtained additional analytical data
from sampling conducted by sanitation districts and MP&M industry trade associations. Sections
3.1, 3.4, and 3.5 describe the MP&M sampling program and sampling episodes conducted by
sanitation districts and MP&M industry trade associations. All data presented in this section have
undergone complete analytical QA/QC.
During the MP&M sampling program, EPA collected 444 wastewater samples
representing 50 distinct unit operations and rinses. These samples, which characterize unit
operations that comprise approximately 90 percent of the total MP&M process wastewater
discharge flow, are discussed in this section. The MP&M surveys identified an additional 20 unit
operations and 24 rinses, accounting for approximately 10 percent of MP&M process wastewater
discharge flow. EPA transferred data to these operations and rinses from the sampling data, based
on process characteristics, as discussed in Section 12.1.2.
Unit operation-specific analytical data for the operations sampled during the
MP&M sampling program are contained in the administrative record for this rulemaking.
5.1 Hexavalent Chromium-Bearing Wastewater
Hexavalent chromium-bearing wastewater contains elevated concentrations of
hexavalent chromium along with other metals such as aluminum or iron. The wastewater is
generally acidic. Sections 5.1.1 and 5.1.2 discuss hexavalent chromium-bearing wastewater
generated from MP&M unit operations and as influent to chromium-reduction wastewater
treatment units, respectively.
5-1
-------
5.0 - Wastewater Characteristics
5.1.1
Unit Operations Generating Hexavalent Chromium-Bearing Wastewater
Table 5-1 summarizes the unit operations and associated rinses that generate
hexavalent chromium-bearing wastewater and the number of samples collected of each.
Table 5-1
Number of Process and Rinse Samples for Unit Operations That Generate
Hexavalent Chromium-Bearing Wastewater
No. of Process No. of Rinse
Unit Operation Samples Samples
Acid Treatment with Chromium
Anodizing with Chromium
Chromate Conversion Coating
Electroplating with Chromium
Wet Air Pollution Control for Chromium-Bearing Operations
1
3
15
4
6
3
7
21
14
NA
Source: MP&M surveys and MP&M site visits.
NA - Not applicable. No associated rinse.
Hexavalent chromium is present in wastewater as a component of the process bath
(e.g., chromic acid anodizing, chromate conversion coating, chromium electroplating). MP&M
facilities install wet air pollution control devices to control air emissions of the chromium process
bath constituents. Total and hexavalent chromium concentrations in process baths average 24,022
mg/L and 10 mg/L, respectively. In the associated rinses, the maximum concentration for total and
hexavalent chromium from EPA's sampling was 17,300 mg/L and 21.2 mg/L, respectively.
Table 5-2 summarizes the MP&M analytical data for total and hexavalent chromium in wastewater
from unit operations and associated rinses that generate total and hexavalent chromium-bearing
wastewater. Based on the process chemistry of the unit operations (e.g., chromium is present in
the hexavalent form in a chromic acid solution), the Agency believes that some chromium present
in this wastewater is in the hexavalent form. For the purposes of estimating compliance costs, the
Agency assumed that all chromium in this wastewater is in the hexavalent form. EPA made this
assumption to provide a conservative assessment of the costs associated with chromium reduction
treatment. (See Section 11 for a discussion on EPA's Design and Cost Model).
5-2
-------
5.0 - Wastewater Characteristics
Table 5-2
Summary of Analytical Data for Chromium From Unit Operations and Rinses
Generating Chromium-Bearing Wastewater
Source of
Pollutant
Unit
Operations
Rinses
Chromium
Form
Total
Hexavalent
Total
Hexavalent
No. of
Samples
Analyzed
29
2
45
6
No. of
Detects
29
1
45
6
Concentrations (mg/L)
Minimum
0.045
10
0.22
2.1
Maximum
139,000
10
17,300
21.2
Mean
24,022
10
1,229
10.3
Median
2,410
10
19.3
8
Source: MP&M sampling program.
5.1.2
Chromium-Bearing Raw Wastewater Characteristics
Typically, MP&M facilities segregate hexavalent chromium-bearing wastewater
generated from the unit operations listed in Table 5-1 and treat it in a chromium reduction unit
before commingling with other process wastewater for further treatment. Section 8.2.1 describes
chromium reduction technologies used in the MP&M industry. This segregated wastestream
requires preliminary treatment to reduce hexavalent chromium to trivalent chromium since
hexavalent chromium is not effectively treated in chemical precipitation systems. Table 5-3
summarizes the analytical data for hexavalent chromium and total chromium in the raw influent to
chromium reduction units. (See Section 10.0 for a discussion on achievable effluent
concentrations of chromium following chromium reduction and chemical precipitation).
Table 5-3
Summary of Analytical Data for Chromium in Chromium-Bearing Raw
Wastewater at Influent to Hexavalent Chromium Treatment
Form of Chromium
Total Chromium
Hexavalent Chromium
No. of
Samples
Analyzed
51
21
No. of
Detects
51
18
Concentrations (mg/L)
Minimum
2.41
0.027
Maximum
432
20
Mean
57.8
6.70
Median
19.5
4.0
Source: MP&M sampling program.
5-3
-------
5.0 - Wastewater Characteristics
5.2
Cyanide-Bearing Wastewater
Cyanide-bearing wastewater contains elevated concentrations of cyanide along
with other metals such as copper, cadmium, or zinc. High concentrations of cyanide are typically
found in electroplating baths. Cyanide may be analyzed as total cyanide (i.e., all forms included),
amenable cyanide (i.e., cyanide present in forms amenable to treatment using alkaline
chlorination), or weak-acid-dissociable cyanide (i.e., cyanide that dissociates in a weak acid).
For the purposes of sizing and costing alkaline chlorination systems, EPA made the conservative
assumption that all detected total cyanide was present in a form amenable to alkaline chlorination.
Sections 5.2.1 and 5.2.2 discuss cyanide-bearing wastewater generated from MP&M unit
operations and as influent to cyanide treatment units, respectively.
5.2.1
Unit Operations Generating Cyanide-Bearing Wastewater
Table 5-4 summarizes the unit operations and associated rinses that generate
cyanide-bearing wastewater and the number of samples collected of each.
Table 5-4
Number of Process and Rinse Samples for Unit Operations
That Generate Cyanide-Bearing Wastewater
Unit Operation
Alkaline Treatment with Cyanide
Electroplating with Cyanide
Wet Air Pollution Control for Cyanide-Bearing Operations
No. of Process
Samples
2
8a
3
No. of Rinse Samples
4
23
NA
Source: MP&M surveys and MP&M site visits.
NA - Not applicable. No associated rinse.
a Does not include one sample from a gold-cyanide electroplating bath that was only analyzed for metals.
Cyanide is present as a component of electroplating and cleaning baths and in wet
air pollution control wastewater for cyanide-bearing unit operations. Table 5-5 summarizes the
analytical data for total and amenable cyanide collected during the MP&M sampling program from
individual unit operations and their associated rinses that generate cyanide-bearing wastewater.
Cyanide electroplating baths and rinses also contain several metal pollutants (typically cadmium,
copper, or silver) depending on the type of metal being electroplated.
5-4
-------
5.0 - Wastewater Characteristics
Table 5-5
Summary of Analytical Data for Cyanide from Unit Operations and Rinses
Generating Cyanide-Bearing Wastewater
Source of
Pollutant
Unit
Operations
Rinses
Cyanide
Form
Total
Amenable
Total
Amenable
No. of
Samples
Analyzed
13
0
24
1
No. of
Detects
13
NA
24
1
Concentrations (mg/L)
Minimum
0.12
NA
0.054
0.34
Maximum
100,000
NA
51,000
0.34
Mean
18,964
NA
5,663
0.34
Median
9,370
NA
12
0.34
Source: MP&M sampling program.
NA - Not applicable. No samples were analyzed for amenable cyanide.
5.2.2
Cyanide-Bearing Raw Wastewater Characteristics
Typically, MP&M facilities segregate cyanide-bearing wastewater generated from
the unit operations listed in Table 5-4 and treat it in a cyanide destruction unit before commingling
with other process wastewater for further treatment. This preliminary treatment prevents cyanide
complexes from forming in the commingled wastewater. These complexes decrease the
effectiveness of chemical precipitation. Section 8.2.3 discusses cyanide treatment technologies.
Table 5-6 summarizes the analytical data for cyanide in the influent to cyanide treatment units.
(See Section 10.0 for a discussion of achievable effluent concentrations of cyanide following
cyanide destruction.)
Table 5-6
Summary of Analytical Data for Cyanide in Cyanide-Bearing Raw
Wastewater at Influent to Cyanide Treatment
Source of
Pollutant
Total Cyanide
Amenable Cyanide
No. of Samples
Analyzed
91
65
No. of Detects
88
59
Concentrations (mg/L)
Minimum
0.024
0.01
Maximum
1,110
394
Mean
45.4
35.8
Median
3.89
2.21
Source: MP&M sampling program.
5-5
-------
5.0 - Wastewater Characteristics
5.3 Oil-Bearing and Organic Pollutant-Bearing Wastewater
Oil-bearing wastewater contains elevated concentrations of oil. This wastewater
may need additional treatment for the removal of toxic organics. Oil-bearing wastewater is
classified as either free oils or oil/water emulsions. Sections 5.3.1 and 5.3.2 discuss wastewater
bearing oil and organic pollutants generated from MP&M unit operations and as influent to oily
wastewater treatment units, respectively.
5.3.1 Unit Operations Generating Oil-Bearing and/or Organic Pollutant-Bearing
Wastewater
Table 5-7 summarizes the unit operations and associated rinses that generate
oil-bearing wastewater and the number of samples collected of each.
5-6
-------
5.0 - Wastewater Characteristics
Table 5-7
Number of Process and Rinse Samples For Unit Operations That Generate
Oil-Bearing and/or Organic Pollutant-Bearing Wastewater
Unit Operation
Alkaline Cleaning for Oil Removal
Aqueous Degreasing
Barrel Finishing
Bilge Water
Corrosion Preventive Coating
Dry Dock
Electrical Discharge Machining
Electrolytic Cleaning
Floor Cleaning
Grinding
Heat Treating
Impact Deformation
Machining
Painting - Spray or Brush
Painting - Immersion
Steam Cleaning
Solder Flux Cleaning
Solder Fusing
Testing
Thermal Cutting
Washing Finished Products
No. of Process Samples
30
12
10
1
5
4
1
7
6
5
3
1
16
6
1
8
3
0
7
2
4
No. of Rinse Samples
30
6
0
0
3
0
0
14
0
0
7
0
0
0
2
0
0
3
2
0
3
Source: MP&M surveys and MP&M site visits.
Tables 5-8 and 5-9 summarize the analytical data collected during the MP&M
sampling program from individual unit operations that generate oil-bearing wastewater and their
associated rinses, respectively. MP&M facilities typically use oil/water emulsions as coolants
and lubricants in machining, grinding, and deformation operations. Oil is also present as a
contaminant in wastewater from cleaning operations. The maximum concentration of oil and
grease in wastewater sampled by EPA from these unit operations was 36,850 mg/L (from an
alkaline cleaning bath), while the maximum concentration of oil and grease in the wastewater from
the rinses associated with these unit operations was 9,195 mg/L.
As shown in Tables 5-8 and 5-9, the oil-bearing wastewater also contains
numerous organic pollutants. These pollutants are either components of the oil/water emulsions or
contaminants in the cleaning solutions. The maximum organic pollutant concentration found in
5-7
-------
5.0 - Wastewater Characteristics
EPA samples was 19,813 mg/L of benzole acid from a testing unit operation. The maximum
organic pollutant concentration in the rinses was 160 mg/L for n-tetradecane from a testing rinse
operation. Tables 5-8 and 5-9 show that these unit operations also contain conventional, non-
conventional, and metal pollutants.
A major source of organic pollutants at MP&M facilities is solvent degreasing.
Solvent degreasing operations use organic solvents such as trichloroethylene or mineral spirits,
and do not use water. Therefore, for the purposes of the MP&M effluent guidelines, EPA did not
consider waste from solvent degreasing a regulated wastewater. In rare situations, EPA identified
rinses following solvent degreasing. EPA classified these rinses as MP&M wastewater. The
Agency classified cleaning operations that use an emulsion of water and solvents as emulsion
cleaning (a subset of alkaline cleaning) and considered these waste streams as MP&M regulated
wastewater.
Table 5-8
Analytical Data for Unit Operations Generating Oil-Bearing and/or
Organic-Bearing Wastewater
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Organic Pollutants
1,1,1 -Trichloroethane
1 , 1 ,2,2-Tetrachloroethane
1 , 1 ,2-Trichloroethane
1 ,2-Dichlorobenzene
2,4,6-Trichlorophenol
2,4-Dimethylphenol
4-Chloro-3 -Methy Iphenol
4-Nitrophenol
Acrolein
Acrylonitrile
Anthracene
Benzene
Bis(2-ethylhexyl) Phthalate
Bromodichloromethane
Butyl Benzyl Phthalate
Chlorobenzene
Chloroethane
Chloroform
72
70
72
72
72
71
72
70
72
72
72
72
72
72
72
72
72
72
1
1
1
1
1
4
11
1
1
1
1
2
21
3
1
2
1
5
0.011
0.011
0.012
0.638
0.014
0.016
0.011
0.424
0.161
0.061
0.193
0.014
0.012
0.012
0.066
0.028
8.34
0.010
0.011
0.011
0.012
0.638
0.014
0.064
91.1
0.424
0.161
0.061
0.193
0.044
143
0.072
0.066
0.058
8.34
0.019
0.011
0.011
0.012
0.638
0.014
0.051
18.2
0.424
0.161
0.061
0.193
0.03
7.44
0.032
0.066
0.043
8.34
0.014
0.011
0.011
0.012
0.638
0.014
0.062
0.587
0.424
0.161
0.061
0.193
0.029
0.085
0.012
0.066
0.043
8.34
0.013
-------
5.0 - Wastewater Characteristics
Table 5-8 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Organic Pollutants (continued)
Chloromethane
Di-n-butyl Phthalate
Di-n-octyl Phthalate
Dibromochloromethane
Dimethyl Phthalate
Ethylbenzene
Fluoranthene
Fluorene
Methylene Chloride
n-nitrosodiphenylamine
Naphthalene
Phenanthrene
Phenol
Tetrachloroethene
Toluene
Trichloroethene
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
1
4
1
2
2
5
4
2
3
1
5
4
21
2
7
8
0.069
0.012
0.020
0.010
0.021
0.028
0.029
0.010
0.028
0.025
0.019
0.101
0.012
0.015
0.029
0.019
0.069
0.070
0.020
0.011
2.000
2.91
0.243
0.021
6.76
0.025
1.839
5.50
8.84
0.02
0.653
0.042
0.069
0.038
0.020
0.011
1.010
0.773
0.132
0.015
2.27
0.025
0.413
1.47
1.05
0.02
0.162
0.024
0.069
0.035
0.020
0.011
1.010
0.191
0.129
0.015
0.030
0.025
0.081
0.143
0.05
0.018
0.103
0.021
Priority Metal Pollutants
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Cyanide
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
131
132
132
132
132
132
10
132
132
132
131
132
131
132
40
57
21
71
104
123
7
78
28
94
37
39
20
121
0.004
0.001
0.000
0.002
0.007
0.006
0.004
0.006
0.000
0.013
0.001
0.003
0.001
0.008
0.804
1.65
0.025
12.1
255
190
0.232
1,450
0.017
80.9
1.57
2.12
0.113
1,160
0.124
0.100
0.004
1.12
5.43
6.58
0.078
29.9
0.001
2.24
0.099
0.175
0.021
37.2
0.040
0.021
0.002
0.097
0.136
0.660
0.059
0.538
0.000
0.164
0.021
0.016
0.018
1.39
Conventional Pollutants
BOD 5 -day (Carbonaceous)
Oil And Grease
64
63
56
59
3
2.4
64,900
570,000
3,207
28,592
645
790
5-9
-------
5.0 - Wastewater Characteristics
Table 5-8 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Conventional Pollutants (continued)
Oil and Grease (as HEM)
pH
Total Suspended Solids
66
69
132
50
69
127
7.75
3.44
4
36,850
13.9
43,580
2,351
8.85
1,940
211
8.24
185
Nonconventional Organic Pollutants
1,4-Dioxane
1 -Methy Ifluorene
1 -Methy Iphenanthrene
2-(Methylthio)Benzothiazole
2-Butanone
2-Hexanone
2-Isopropylnaphthalene
2-Methylnaphthalene
2-Picoline
2-Propanone
3 , 6-Dimethy Iphenanthrene
4-Methyl-2-Pentanone
Acetophenone
Alpha-terpineol
Benzoic Acid
Benzyl Alcohol
Biphenyl
Cis- 1 ,3-dichloropropene
Diphenyl Ether
Diphenylamine
Hexanoic Acid
Isobutyl Alcohol
m+p xylene
m-xylene
n,n-dimethylformamide
n-decane
n-docosane
n-dodecane
n-eicosane
n-hexacosane
72
72
72
72
72
72
72
72
72
72
72
72
72
71
72
72
72
72
72
72
72
72
47
25
72
72
72
72
72
72
2
3
3
1
13
3
1
9
1
40
1
10
1
12
13
3
2
1
1
2
24
3
2
3
5
9
23
24
29
20
0.077
0.014
0.122
0.028
0.057
0.124
7.34
0.011
0.072
0.060
8.50
0.124
0.566
0.012
0.071
0.023
0.014
0.012
0.013
0.024
0.019
0.012
0.013
0.153
0.028
0.017
0.013
0.011
0.012
0.011
1.00
2.60
5.65
0.028
38.3
0.505
7.34
3.14
0.072
11.9
8.5
159
0.566
14.1
19,813
0.208
0.038
0.012
0.013
0.026
1,490
1.31
0.352
5.06
0.665
1.33
141
36.8
14.1
109
0.539
0.912
1.97
0.028
3.70
0.263
7.34
0.511
0.072
0.966
8.50
22.6
0.566
2.69
1,525
0.108
0.026
0.012
0.013
0.025
66.3
0.446
0.183
2.45
0.265
0.462
7.98
3.60
1.40
7.43
0.539
0.123
0.147
0.028
0.101
0.161
7.34
0.236
0.072
0.220
8.50
0.457
0.566
1.780
0.287
0.094
0.026
0.012
0.013
0.025
0.903
0.018
0.183
2.13
0.036
0.132
0.164
0.419
0.190
0.099
5-10
-------
5.0 - Wastewater Characteristics
Table 5-8 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Vonconventional Organic Pollutants (continued)
n-hexadecane
n-octacosane
n-octadecane
n-tetracosane
n-tetradecane
n-triacontane
o+p xylene
o-xylene
p-cresol
p-cymene
Styrene
Toluene, 2,4-diamino-
Trichlorofluoromethane
Tripropyleneglycol Methyl Ether
72
72
72
72
72
72
25
47
72
72
72
72
72
72
28
8
28
17
29
12
3
6
6
2
1
1
1
5
0.015
0.035
0.01
0.011
0.011
0.012
0.063
0.010
0.010
0.021
1.184
101
0.106
1.93
95.3
61.1
264
116
48.5
31.9
2.01
0.201
4.31
0.1
1.18
101
0.106
5,254
6.64
10.4
13.1
9.34
6.48
3.78
1.19
0.044
0.74
0.04
1.18
101
0.106
1,462
0.444
0.524
0.198
0.267
0.674
0.433
1.48
0.013
0.029
0.036
1.18
101
0.106
413
Nonconventional Metal Pollutants
Aluminum
Barium
Bismuth
Boron
Calcium
Cobalt
Gold
Iridium
Iron
Lutetium
Magnesium
Manganese
Molybdenum
Neodymium
Niobium
Potassium
Silicon
Sodium
Strontium
132
132
1
132
132
132
6
1
132
1
132
132
132
1
1
1
1
132
1
113
114
1
113
128
54
2
1
126
1
121
122
87
1
1
1
1
128
1
0.039
0.001
0.058
0.059
0.274
0.005
0.081
0.596
0.016
0.007
0.088
0.002
0.003
0.020
0.104
0.574
19.9
1.61
8.02
414
31.4
0.058
2,290
981
1.26
1.66
0.596
2,790
0.007
213
24.1
774
0.020
0.104
0.574
19.9
68,700
8.0186
22.3
1.88
0.058
87.1
63.9
0.131
0.871
0.596
50.2
0.007
24.6
1.36
11.7
0.020
0.104
0.574
19.9
3,847
8.02
1.83
0.108
0.058
1.27
38.75
0.037
0.871
0.596
6.10
0.007
10.5
0.271
0.095
0.020
0.104
0.574
19.9
299
8.02
5-11
-------
5.0 - Wastewater Characteristics
Table 5-8 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Metal Pollutants (continued)
Sulfur
Tantalum
Tin
Titanium
Tungsten
Vanadium
Ytterbium
Yttrium
1
1
132
132
1
132
1
132
1
1
61
86
1
51
1
37
0.636
0.134
0.004
0.001
0.175
0.005
0.006
0.001
0.636
0.134
852
30.0
0.175
0.482
0.006
0.900
0.636
0.134
15.7
0.658
0.175
0.072
0.006
0.045
0.636
0.134
0.101
0.045
0.175
0.023
0.01
0.008
Other Nonconventional Pollutants
Acidity
Ammonia As Nitrogen
Chemical Oxygen Demand (COD)
Chloride
Fluoride
Hexavalent Chromium
Sulfate
Total Alkalinity
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbons (As SGT-
HEM)
Total Phosphorus
Total Recoverable Phenolics
Total Sulfide
51
43
107
52
59
63
66
53
128
44
67
65
35
105
9
17
36
103
49
56
13
54
52
128
41
63
42
34
87
5
1.00
0.160
22.4
2.00
0.130
0.016
1.50
51.5
33.5
0.200
4.26
6.00
0.065
0.005
1.00
250,000
1,600
366,000
48,000
35.0
1.70
46,000
92,000
411,420
580
118,000
6,230
7,170
33.8
11.0
14,818
71.8
27,871
1,604
3.92
0.207
2,483
13,989
23,538
68.9
7,184
481
291
1.67
4.40
9.00
2.54
4,930
180
1.35
0.055
272.23
2,000
4,500
37.0
471
52.5
18.85
0.197
2.00
Source: MP&M sampling program.
5-12
-------
5.0 - Wastewater Characteristics
Table 5-9
Analytical Data for Rinses Generating Oil-Bearing and/or
Organic-Bearing Wastewater
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Organic Pollutants
1,1,1 -Trichloroethane
1 , 1 -Dichloroethane
2, 6-Dinitrotoluene
4-Chloro-3 -Methy Iphenol
Bis(2-Ethylhexyl) Phthalate
Bromodichloromethane
Chloroform
Di-n-butyl Phthalate
Ethylbenzene
Methylene Chloride
n-nitrosodi-n-propylamine
Naphthalene
Phenanthrene
Phenol
Toluene
Trichloroethene
40
40
40
40
40
40
40
40
40
40
40
40
40
40
40
40
1
1
1
2
10
4
11
4
3
1
1
3
1
5
2
6
0.023
0.039
0.616
0.023
0.011
0.010
0.010
0.014
0.021
0.016
0.132
0.021
0.527
0.011
0.011
0.011
0.023
0.039
0.616
0.050
1.15
0.014
0.035
0.019
0.039
0.016
0.132
2.01
0.527
8.28
0.045
0.022
0.023
0.039
0.616
0.037
0.336
0.011
0.017
0.017
0.029
0.016
0.132
0.892
0.527
1.67
0.028
0.02
0.023
0.039
0.616
0.037
0.187
0.010
0.012
0.017
0.028
0.016
0.132
0.643
0.527
0.024
0.028
0.02
Priority Metal Pollutants
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Cyanide
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
69
70
70
70
70
70
2
70
70
70
69
70
69
70
18
15
5
22
41
59
2
23
11
38
5
16
5
53
0.0028
0.0013
0.0011
0.002
0.009
0.008
0.010
0.031
0.00005
0.008
0.001
0.004
0.002
0.009
0.256
0.303
0.005
11.9
104
14.7
1.45
6.89
0.001
10.3
0.232
0.081
0.036
46.7
0.047
0.037
0.002
0.618
2.88
0.958
0.730
1.17
0.0003
0.744
0.082
0.022
0.014
2.28
0.032
0.008
0.002
0.052
0.159
0.144
0.730
0.495
0.0002
0.105
0.031
0.010
0.006
0.134
5-13
-------
5.0 - Wastewater Characteristics
Table 5-9 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Conventional Pollutants
BOD 5 -day (Carbonaceous)
Oil And Grease
Oil And Grease (As HEM)
pH
Total Suspended Solids
38
23
38
38
70
34
16
27
38
56
4.00
1.35
5.00
2.40
4.00
12,900
2,700
9,195
13.2
2,560
1,209
440
472
9.24
178
179
41.5
42
9.31
64.2
Nonconventional Organic Pollutants
1,4-Dioxane
1 -Methy Ifluorene
1 -Methy Iphenanthrene
2-Butanone
2-Isopropylnaphthalene
2-Methylnaphthalene
2-Propanone
3 , 6-Dimethy Iphenanthrene
4-Methyl-2-Pentanone
Alpha-Terpineol
Benzoic Acid
Benzyl Alcohol
Hexanoic Acid
m+p xylene
m-xylene
n,n-dimethylformamide
n-decane
n-docosane
n-dodecane
n-eicosane
n-hexacosane
n-hexadecane
n-octacosane
n-octadecane
n-tetracosane
n-tetradecane
n-triacontane
o-cresoL
o -xylene
p-cymene
Phenothiazine
40
40
40
40
40
40
40
40
40
39
40
40
40
25
15
40
40
40
40
40
40
40
40
40
40
40
40
40
25
40
40
1
1
1
3
1
1
14
1
2
2
6
2
15
1
2
1
1
7
6
13
8
10
4
10
10
6
4
1
1
1
1
0.196
0.129
1.02
0.074
1.57
1.10
0.055
0.811
0.190
65.3
0.108
2.73
0.015
0.104
0.036
0.011
5.01
0.018
1.77
0.011
0.011
0.011
0.041
0.018
0.012
0.221
0.030
0.012
0.056
0.190
0.582
0.196
0.129
1.02
0.126
1.57
1.10
3.10
0.811
17.4
67.3
6.61
24.8
28.4
0.10
0.08
0.011
5.01
6.47
53.3
2.4
1.46
52.7
1.37
4.03
17.0
160
0.477
0.012
0.056
0.190
0.582
0.196
0.129
1.02
0.093
1.57
1.10
0.444
0.811
8.80
66.3
1.76
13.8
2.40
0.104
0.056
0.011
5.01
1.07
15.3
0.490
0.443
11.0
0.624
0.952
1.87
53.3
0.217
0.012
0.056
0.190
0.582
0.196
0.129
1.02
0.078
1.57
1.10
0.197
0.811
8.80
66.3
1.05
13.8
0.536
0.104
0.056
0.011
5.01
0.030
7.24
0.172
0.250
0.755
0.540
0.159
0.094
3.12
0.180
0.012
0.056
0.190
0.582
5-14
-------
5.0 - Wastewater Characteristics
Table 5-9 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Organic Pollutants (continued)
Trichlorofluoromethane
Tripropyleneglycol Methyl Ether
40
40
1
3
0.036
0.413
0.036
4.18
0.036
2.43
0.036
2.71
Nonconventional Metal Pollutants
Aluminum
Barium
Boron
Calcium
Cobalt
Gold
Iron
Magnesium
Manganese
Molybdenum
Palladium
Sodium
Tin
Titanium
Vanadium
Yttrium
70
70
70
70
70
4
70
70
70
70
3
70
70
70
70
70
36
58
48
66
11
2
53
65
51
36
1
68
25
23
19
7
0.031
0.001
0.019
0.940
0.007
0.056
0.034
0.137
0.002
0.006
0.054
1.63
0.006
0.002
0.003
0.002
19.7
1.61
838
175
0.546
0.086
453
37.3
8.63
187
0.054
19,100
10.9
1.53
0.182
0.020
2.72
0.181
28.0
34.8
0.102
0.071
18.1
9.69
0.394
5.34
0.054
603
1.18
0.259
0.030
0.008
0.823
0.044
0.195
22.8
0.024
0.071
0.275
8.00
0.040
0.023
0.054
87.2
0.056
0.040
0.023
0.007
Other Nonconventional Pollutants
Acidity
Ammonia as Nitrogen
Chemical Oxygen Demand (COD)
Chloride
Fluoride
Hexavalent Chromium
Sulfate
Total Alkalinity
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbons (As SGT-
Total Phosphorus
Total Recoverable Phenolics
Total Sulfide
19
13
47
19
19
38
26
19
70
10
38
37
7
48
1
8
8
44
19
19
12
22
18
69
7
35
19
7
37
1
2.00
0.02
5.20
3.00
0.11
0.011
6.60
24
26
0.36
2.66
5.00
0.06
0.0056
12.0
120
0.920
32,700
64,500
135
0.069
780
3,800
120,000
149
10,100
7,367
11.0
2.78
12.0
26.5
0.439
2,561
3,435
7.80
0.025
122
518
3,563
23
867
455
4.1
0.233
12.0
16.0
0.43
347
22.0
0.710
0.022
29.0
195
708
1.68
120
28.0
2.16
0.070
12.0
Source: MP&M sampling program.
5-15
-------
5.0 - Wastewater Characteristics
5.3.2
Oil-Bearing and Organic Pollutant-Bearing Raw Wastewater Characteristics
Wastewater containing oil and organic pollutants generated from the unit operations
listed in Table 5-7 generally requires treatment to separate oil from the wastewater. If the oils are
free or floating, then the oil and water can be separated using physical means such as oil skimming
or ultrafiltration. If the oil is emulsified, techniques such as chemical emulsion breaking may be
required before physical separation. Oil/water separation technologies also remove organic
pollutants that are more soluble in oil than in water. Sections 8.2.5 and 8.3.2 discuss oil-water
separation technologies used in the MP&M industry. Table 5-10 summarizes the characteristics of
raw wastewater influent to oily wastewater treatment systems. (See Section 10.0 for a discussion
on achievable effluent concentrations of oil and grease and organics following oil/water
separation and chemical precipitation.)
Table 5-10
Analytical Data for Oil-Bearing and Organic Pollutant-Bearing Raw
Wastewater Streams at Influent to Oil/Water Separation
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Organic Pollutants
1,1,1 -Trichloroethane
1 ,2-Dichlorobenzene
2,4-Dimethylphenol
2-Nitrophenol
4-Chloro-3 -Methy Iphenol
Acenaphthene
Acrolein
Anthracene
Benzene
Bis(2-Ethylhexyl) Phthalate
Butyl Benzyl Phthalate
Carbon Tetrachloride
(Tetrachloromethane)
Chloroform
Chloromethane
Di-n-butyl Phthalate
Di-n-octyl Phthalate
Ethylbenzene
82
82
81
82
82
82
77
82
82
81
81
82
82
82
81
82
82
5
1
2
1
18
5
1
1
2
62
7
3
6
1
8
10
18
0.006
0.638
0.017
0.025
0.247
0.006
0.168
0.007
0.007
0.007
0.024
0.011
0.010
0.736
0.011
0.010
0.010
0.022
0.638
0.270
0.025
3,834
1.82
0.168
0.007
0.012
216
2.73
0.046
0.038
0.736
0.193
19.7
0.260
0.013
0.638
0.144
0.025
706
0.396
0.168
0.007
0.010
6.66
0.440
0.025
0.019
0.736
0.087
2.37
0.077
0.013
0.638
0.144
0.025
101
0.025
0.168
0.007
0.010
0.157
0.065
0.017
0.016
0.736
0.080
0.332
0.036
5-16
-------
5.0 - Wastewater Characteristics
Table 5-10 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Organic Pollutants (continued)
Fluorene
n-Nitrosodiphenylamine
Naphthalene
Phenanthrene
Phenol
Pyrene
Tetrachloroethene
Toluene
82
82
82
82
81
81
82
82
6
5
15
17
31
2
1
21
0.010
0.025
0.011
0.012
0.018
0.031
0.006
0.006
9.93
2.59
8.91
5.30
27.1
1.01
0.006
1.35
1.71
1.34
1.04
0.486
1.31
0.521
0.006
0.199
0.067
1.69
0.046
0.033
0.138
0.521
0.006
0.033
Priority Metal Pollutants
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
86
86
86
86
86
86
86
86
86
86
86
86
86
33
38
20
62
74
86
70
26
71
13
18
6
84
0.002
0.002
0.0002
0.002
0.003
0.027
0.006
0.0001
0.012
0.001
0.004
0.001
0.145
0.105
0.534
0.187
12.1
15.9
232
210
0.003
18.4
0.124
2.8
0.068
664
0.022
0.036
0.036
0.805
0.726
23.0
17.1
0.0009
0.913
0.028
0.272
0.012
26.0
0.017
0.006
0.002
0.030
0.071
0.408
0.239
0.0004
0.155
0.011
0.022
0.001
1.66
Conventional Pollutants
BOD 5 -Day (Carbonaceous)
Oil And Grease
Total Suspended Solids
75
86
86
69
84
84
4
8.33
6
21,300
261,500
100,000
2,745
12,149
3,712
675
872
260
Nonconventional Organic Pollutants
1,4-Dioxane
1 -Methy Ifluorene
1 -Methy Iphenanthrene
1 -Naphthylamine
2-(Methylthio)Benzothiazole
2-Butanone
2-Hexanone
77
77
77
77
77
77
77
2
10
9
1
3
9
2
0.080
0.010
0.015
0.034
0.012
0.130
0.505
0.105
1.72
1.23
0.034
0.023
0.483
0.512
0.093
0.223
0.243
0.034
0.017
0.287
0.509
0.093
0.020
0.027
0.034
0.015
0.256
0.509
5-17
-------
5.0 - Wastewater Characteristics
Table 5-10 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Organic Pollutants (continued)
2-Isopropylnaphthalene
2-Methylnaphthalene
2-Propanone
3 , 6-Dimethy Iphenanthrene
4-Methyl-2-Pentanone
Acetophenone
Alpha-Terpineol
Aniline
Benzoic Acid
Benzyl Alcohol
Biphenyl
Carbazole
Carbon Bisulfide
Dibenzofuran
Dibenzothiophene
Diphenylamine
Hexanoic Acid
m+p-Xylene
m-Xylene
n,n-Dimethylformamide
n-Decane
n-Docosane
n-Dodecane
n-Eicosane
n-Hexacosane
n-Hexadecane
n-Nitrosomorpholine
n-Octacosane
n-Octadecane
n-Tetracosane
n-Tetradecane
n-Triacontane
o+p-Xylene
o-Cresol
77
77
77
77
77
77
77
77
77
77
77
77
77
77
76
77
77
39
38
77
77
77
77
76
77
77
77
77
77
76
77
76
38
77
2
17
62
5
10
3
32
1
4
11
10
1
5
1
3
5
31
11
6
2
32
43
47
52
32
58
2
8
59
32
61
10
6
1
0.421
0.029
0.060
0.013
0.073
0.014
0.011
0.014
0.108
0.011
0.014
0.035
0.045
0.014
0.015
0.034
0.011
0.023
0.018
0.014
0.013
0.011
0.017
0.010
0.014
0.012
0.012
0.075
0.011
0.021
0.011
0.016
0.011
0.047
3.49
13.0
28.8
1.28
6.72
0.092
189
0.014
0.522
10.8
1.54
0.035
0.466
0.014
1.293
1.99
31.9
0.457
0.312
0.023
27.7
79.7
207
109
217
145
0.135
70.7
162
56.8
243
25.6
0.030
0.047
1.96
1.17
4.48
0.583
0.835
0.051
19.9
0.014
0.288
1.08
0.220
0.035
0.312
0.014
0.452
1.24
4.61
0.169
0.071
0.019
2.94
2.87
23.2
6.67
9.09
8.60
0.074
16.1
6.43
3.32
15.7
5.60
0.021
0.047
1.96
0.132
0.858
0.371
0.153
0.047
1.59
0.014
0.261
0.141
0.054
0.035
0.369
0.014
0.048
1.66
0.508
0.139
0.024
0.019
0.086
0.119
0.919
0.220
0.169
0.362
0.074
6.17
0.273
0.248
0.277
1.55
0.021
0.047
5-18
-------
5.0 - Wastewater Characteristics
Table 5-10 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Organic Pollutants (continued)
o-Xylene
p-Cresol
p-Cymene
Pentamethylbenzene
Pyridine
Safrole
Tripropyleneglycol Methyl Ether
39
77
77
77
77
77
77
14
10
10
1
15
1
11
0.012
0.018
0.015
1.24
0.014
0.065
0.447
0.130
1.09
14.6
1.24
3.42
0.065
1,550
0.065
0.297
1.54
1.24
1.02
0.065
386
0.071
0.056
0.079
1.24
0.063
0.065
30.1
Nonconventional Metal Pollutants
Aluminum
Barium
Boron
Calcium
Cobalt
Gold
Iron
Magnesium
Manganese
Molybdenum
Sodium
Tin
Titanium
Vanadium
Yttrium
86
86
86
86
86
1
86
86
86
86
86
86
86
86
86
76
85
85
85
41
1
84
84
84
66
85
55
64
43
24
0.076
0.019
0.191
1.66
0.008
2.81
0.604
0.180
0.031
0.003
27.1
0.003
0.003
0.004
0.001
134
32
686
2,200
1.22
2.81
940
255
29
40.3
2,030
85.2
1.80
0.482
1.00
14.3
2.06
37.6
170
0.212
2.81
52.7
38.3
1.90
1.50
442
3.22
0.194
0.060
0.091
3.58
0.186
6.39
41.3
0.102
2.81
11.0
11.9
0.373
0.098
210
0.058
0.079
0.025
0.013
Other Nonconventional Pollutants
Ammonia as Nitrogen
Chemical Oxygen
Demand (COD)
Chloride
Fluoride
Hexavalent Chromium
Sulfate
Total Alkalinity
Total Dissolved Solids
Total Kjeldahl Nitrogen
11
85
7
12
71
35
6
82
11
11
85
7
12
14
34
6
82
11
0.290
30
22
0.500
0.010
16
180
272
0.840
160
213,000
450
17
1.74
176,000
4,900
88,800
1,500
44.5
24,961
110
2.94
0.195
15,585
1,498
9,930
302
24.4
5,750
37.0
0.975
0.021
430
210
2,600
8.86
5-19
-------
5.0 - Wastewater Characteristics
Table 5-10 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Other Nonconventional Pollutants (continued)
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbon
(As SGT-HEM)
Total Phosphorus
Total Recoverable Phenolics
Total Sulfide
70
74
20
84
23
68
68
20
81
20
7.66
5.07
0.160
0.005
3.00
106,000
25,431
240
1,360
18.0
7,028
2,213
38.2
59.3
7.85
1,230
511
17.0
0.220
7.00
Source: MP&M sampling program.
5.4 Chelated Metal-Bearing Wastewater
Chelated metal-bearing wastewater contains elevated concentrations of metals,
typically copper or nickel. Sections 5.4.1 and 5.4.2 discuss chelated metal-bearing wastewater
generated from MP&M unit operations and as influent to chelation-breaking wastewater treatment
units, respectively.
5.4.1
Unit Operations Generating Chelated Metal-Bearing Wastewater
Electroless plating operations and rinses are the most common MP&M operations
that generate chelated metal-bearing wastewater. Some cleaning operations also generate chelated
metal-bearing wastewater. MP&M facilities use chelating agents in these unit operations to
prevent metals from precipitating out of solution in the process bath.
During the MP&M sampling program, EPA collected samples of electroless nickel
plating solutions and rinses that generate chelated metal-bearing wastewater. The maximum
concentration of nickel detected in wastewater from the unit operations was 7,530 mg/L, while the
maximum concentration of nickel in the wastewater from rinses was 378 mg/L. Other metals
typically plated using electroless plating include copper, gold, palladium, and cobalt. EPA
expects the concentrations of the plated metals in these solutions and associated rinses to be
similar to the concentrations measured for nickel during the MP&M sampling program.
5.4.2
Chelation-Breaking Raw Wastewater Characteristics
Typical chemical precipitation and sedimentation treatment units do not effectively
remove chelated metals; therefore, chelated metal-bearing wastewater typically requires
segregation and preliminary treatment to break down the metal chelates before commingling with
other metal-bearing waste streams for further treatment. If facilities do not segregate these streams
from other metal-bearing waste streams, the chelated metal will not be efficiently removed. EPA
detected copper concentrations ranging from 570 mg/L to 700 mg/L in influent samples from
5-20
-------
5.0 - Wastewater Characteristics
preliminary treatment systems for electroless copper operations. EPA detected nickel at
concentrations ranging from 0.149 mg/L to 480 mg/L in influent samples from preliminary
treatment systems for electroless nickel operations. (See Section 10.0 for a discussion on
achievable effluent concentrations of these chelated metals following chelation breaking/removal
and chemical precipitation.)
Preliminary treatment may consist of chemical reduction using reducing agents such
as sodium borohydride, hydrazine, dithiocarbamate (measured analytically as ziram) or sodium
hydrosulfite; high-pH precipitation using calcium hydroxide or ferrous sulfate; or filtering the
chelated metals out of solution. Section 8.2.4 describes typical metal chelation-bearing
wastewater treatment technologies used in the MP&M industry.
5.5 General Metal-Bearing Wastewater
All MP&M unit operations can generate metal-bearing wastewater, including those
wastewater streams described in the previous sections. Sections 5.5.1 and 5.5.2 discuss metal-
bearing wastewater not previously discussed that is generated from MP&M unit operations and
treated in chemical precipitation systems, respectively.
5.5.1 Unit Operations Generating General Metal-Bearing Wastewater
Table 5-11 summarizes the unit operations and associated rinses that generate
general metal-bearing wastewater and the number of samples collected of each.
5-21
-------
5.0 - Wastewater Characteristics
Table 5-11
Number of Process and Rinse Samples From Unit Operations That Generate
General Metal-Bearing Wastewater
Unit Operation No. of Process Samples No. of Rinse Samples
Abrasive Blasting
Abrasive Jet Machining
Acid Treatment without Chromium
Adhesive Bonding
Alkaline Treatment without Cyanide
Anodizing without Chromium
Carbon Black Deposition
Chemical Milling
Chemical Conversion Coating without Chromium
Electrochemical Machining
Electroless Plating
Electroplating without Chromium or Cyanide
Electropolishing
Multiple Unit Operation Rinse
Photo Image Developing
Photo Resist Applications
Plasma Arc Machining
Salt Bath Descaling
Stripping (paint)
Stripping (metallic coating)
Welding
Wet Air Pollution Control (includes Acid/ Alkaline
and Fumes and Dust)
3
1
26
1
12
4
1
5
19
1
6
18
1
1
5
1
1
1
10
8
0
16
3
0
57
0
34
4
0
12
42
2
15
41
1
0
11
3
0
3
16
8
1
NA
Source: MP&M surveys and MP&M site visits.
NA - Not Applicable. No associated rinse.
Tables 5-12 and 5-13 summarize the analytical data collected during the MP&M
sampling program for wastewater from unit operations and associated rinses, respectively, that
generate general metal-bearing wastewater. As shown in these tables, the priority metal pollutants
most commonly detected in samples of this wastewater were copper, zinc, chromium, nickel, and
lead. Nonconventional metal pollutants frequently detected include iron, magnesium, boron,
barium, manganese, and aluminum. Metal pollutants are typically present in unit operation process
baths that apply or remove metal, such as electroplating or stripping process baths. EPA detected
metal concentrations of up to 383,000 mg/L in unit operation process baths and up to 85,300 mg/L
in unit operation rinses. This wastewater also typically contained oil and grease, total suspended
solids, and low concentrations of organic pollutants.
5-22
-------
5.0 - Wastewater Characteristics
Table 5-12
Analytical Data from Unit Operations Generating
General Metal-Bearing Wastewater
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
il
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Organic Pollutants
1 ,2,4-Trichlorobenzene
2,4-Dimethylphenol
2,4-Dinitrophenol
2,4-Dinitrotoluene
2,6-Dinitrotoluene
2-Nitrophenol
4,6-Dinitro-o-Cresol
4-Nitrophenol
Acrolein
Benzene
Bis(2-Ethylhexyl) Phthalate
Bromodichloromethane
Chlorobenzene
Chloroform
Chloromethane
Di-n-butyl Phthalate
Di-n-octyl Phthalate
Dibromochloromethane
Ethylbenzene
Fluorene
Methylene Chloride
n-Nitrosodi-n-Propylamine
n-Nitrosodimethylamine
Naphthalene
Nitrobenzene
Phenanthrene
Phenol
Pyrene
Toluene
Trichloroethene
57
54
50
57
57
56
53
54
57
57
57
57
57
57
57
57
57
57
57
57
57
56
57
57
57
57
57
57
57
56
1
3
4
1
2
4
3
4
1
4
15
2
4
6
1
1
2
2
3
1
4
1
1
3
1
1
8
1
2
8
0.109
0.049
0.065
23.4
0.605
0.034
0.037
0.101
0.591
0.015
0.012
0.017
0.011
0.012
0.101
0.105
0.639
0.013
0.020
0.016
0.010
0.841
6.67
0.024
0.119
0.037
0.020
0.016
0.014
0.010
0.109
0.167
335
23.4
6.98
2.15
0.065
14.1
0.591
0.225
18.2
0.017
1.56
0.218
0.101
0.105
1.42
0.015
0.030
0.016
0.173
0.841
6.67
0.208
0.119
0.037
1,044
0.016
0.047
2.29
0.109
0.091
83.7
23.4
3.79
0.574
0.047
3.63
0.591
0.069
2.54
0.017
0.402
0.050
0.101
0.105
1.03
0.014
0.024
0.016
0.062
0.841
6.67
0.103
0.119
0.037
136
0.016
0.031
0.310
0.109
0.056
0.123
23.4
3.79
0.059
0.039
0.153
0.591
0.019
0.326
0.017
0.018
0.017
0.101
0.105
1.03
0.014
0.021
0.016
0.033
0.841
6.67
0.077
0.119
0.037
0.538
0.016
0.031
0.024
5-23
-------
5.0 - Wastewater Characteristics
Table 5-12 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Metal Pollutants
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Cyanide
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
147
147
147
147
147
147
8
147
147
147
147
147
147
146
66
65
38
74
115
135
7
79
31
111
36
50
21
133
0.002
0.001
0.0005
0.002
0.007
0.007
0.027
0.010
0.000
0.007
0.001
0.004
0.001
0.005
3.56
16.4
3.87
57,100
108,000
141,000
4.30
7,150
0.032
84,623
8.00
14.4
2.83
53,200
0.326
0.843
0.300
900
1,951
2,552
0.751
178
0.003
2,837
0.551
0.572
0.196
1,121
0.066
0.057
0.034
0.148
1.57
4.26
0.143
2.48
0.0008
3.18
0.036
0.097
0.021
2.84
Conventional Pollutants
BOD 5 -Day (Carbonaceous)
Oil And Grease
Oil And Grease (As HEM)
pH
Total Suspended Solids
49
79
51
56
143
34
54
23
56
124
4.29
0.315
6.39
0.010
5.00
60,400
260
1,140
14.4
110,000
6,596
19.4
208
7.50
1,742
1,625
4.70
82.0
8.53
115
Nonconventional Organic Pollutants
l,2:3,4-Diepoxybutane
1 ,4-Dinitrobenzene
1,4-Dioxane
1 -Bromo-2-Chlorobenzene
1 -Bromo-3 -Chlorobenzene
1-Methylfluorene
1 -Methy Iphenanthrene
2-Butanone
2-Hexanone
2-Methylnaphthalene
2-Propanone
3 , 6-Dimethy Iphenanthrene
4-Methyl-2-Pentanone
57
57
57
57
57
57
57
57
57
57
57
57
57
1
2
4
5
4
1
1
15
1
2
32
1
8
0.251
1.07
0.304
0.012
0.031
0.035
0.027
0.070
5.02
0.067
0.052
0.013
0.052
0.251
2.96
2.80
0.978
0.490
0.035
0.027
26.1
5.02
0.220
250
0.013
2.78
0.251
2.02
1.10
0.317
0.193
0.035
0.027
3.84
5.02
0.143
10.4
0.013
0.565
0.251
2.02
0.643
0.057
0.126
0.035
0.027
1.05
5.02
0.143
0.465
0.013
0.128
5-24
-------
5.0 - Wastewater Characteristics
Table 5-12 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Organic Pollutants (continued)
Alpha-Terpineol
Aniline
Benzoic Acid
Benzyl Alcohol
Carbon Bisulfide
Dibenzofuran
Dibenzothiophene
Diphenylamine
Hexanoic Acid
Isobutyl Alcohol
m+p Xylene
m-Xylene
Methyl Methacrylate
n,n-Dimethylformamide
n-Decane
n-Docosane
n-Dodecane
n-Eicosane
n-Hexadecane
n-Nitrosomethylphenylamine
n-Nitrosomorpholine
n-Octadecane
n-Tetracosane
n-Tetradecane
o+p Xylene
o-Cresol
o-Toluidine
o-Xylene
p-Cresol
p-Nitroaniline
Resorcinol
Tripropyleneglycol Methyl Ether
56
57
57
57
57
57
57
57
57
57
42
15
57
57
57
57
57
57
57
57
57
57
57
57
15
57
57
42
57
57
57
57
1
6
11
4
1
1
1
1
6
1
1
2
5
2
3
2
2
2
1
1
1
1
1
2
2
3
1
1
8
2
2
7
1.40
0.015
0.051
0.012
0.053
0.140
0.011
0.032
0.012
0.012
0.059
0.018
0.012
0.032
0.083
0.021
0.024
0.020
0.200
1.36
0.040
0.132
0.055
0.044
0.010
0.023
0.030
0.048
0.011
0.051
1.24
0.245
1.40
3.27
8,098
0.393
0.053
0.140
0.011
0.032
31.5
0.012
0.059
0.020
0.797
0.123
3.51
0.051
1.27
0.956
0.200
1.36
0.040
0.132
0.055
0.114
0.910
0.195
0.030
0.048
2.69
26.1
4.12
100
1.40
0.728
754
0.195
0.053
0.140
0.011
0.032
9.08
0.012
0.059
0.019
0.471
0.078
1.32
0.036
0.648
0.488
0.200
1.36
0.040
0.132
0.055
0.079
0.460
0.085
0.030
0.048
0.493
13.1
2.68
33.5
1.40
0.225
1.109
0.189
0.053
0.140
0.011
0.032
5.02
0.012
0.059
0.019
0.586
0.078
0.360
0.036
0.648
0.488
0.200
1.36
0.040
0.132
0.055
0.079
0.460
0.039
0.030
0.048
0.153
13.1
2.68
20.1
Nonconventional Metal Pollutants
Aluminum
147
116
0.027
34,900
1,283
3.84
5-25
-------
5.0 - Wastewater Characteristics
Table 5-12 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Metal Pollutants (continued)
Barium
Boron
Calcium
Cobalt
Gold
Iron
Magnesium
Manganese
Molybdenum
Sodium
Tin
Titanium
Vanadium
Yttrium
147
147
147
147
1
147
147
147
147
147
147
147
147
147
122
122
143
79
1
135
124
119
89
145
71
97
71
30
0.001
0.017
0.146
0.003
0.392
0.008
0.085
0.001
0.006
1.25
0.006
0.002
0.004
0.001
259
17800
1,936
4700
0.392
374,000
960
20,600
197
383,000
22,670
13,250
1,495
2.11
3.60
561
78.3
67.3
0.392
5,892
66.8
265
5.38
16,367
1,090
223
25.5
0.171
0.088
0.858
23.9
0.530
0.392
3.66
14.6
0.319
0.205
534.0
1.88
0.177
0.062
0.038
Other Nonconventional Pollutants
Acidity
Ammonia As Nitrogen
Chemical Oxygen Demand
(COD)
Chloride
Fluoride
Hexavalent Chromium
Sulfate
Total Alkalinity
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbons
(As SGT-HEM)
Total Phosphorus
Total Recoverable Phenolics
Total Sulfide
74
70
82
79
79
52
107
74
143
61
50
51
34
73
2
45
52
77
62
66
9
90
48
141
52
49
9
25
53
1
2.00
0.145
6.90
1.00
0.140
0.008
2.40
2.00
87
0.480
3.70
8.88
0.020
0.006
3.00
600,000
43,000
600,000
328,300
55,500
0.430
755,000
890,000
1,000,000
40,000
54,000
352
11,000
135
3.00
106,486
2,269
32,696
14,478
1,653
0.090
35,877
75,352
114,066
3,158
10,076
90.2
809
5.48
3.00
39,600
16.0
4,700
80.0
3.50
0.025
275
435
23,900
53.8
1,380
25.2
7.50
0.140
3.00
Source: MP&M sampling program.
5-26
-------
5.0 - Wastewater Characteristics
Table 5-13
Analytical Data from Rinses Generating
General Metal-Bearing Wastewater
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Organic Pollutants
1 ,2-Dipheny Ihydrazine
1 ,4-Dichlorobenzene
Bis(2-Ethylhexyl) Phthalate
Bromodichloromethane
Chloroform
Chloromethane
Di-n-butyl Phthalate
Di-n-octyl Phthalate
Dibromochloromethane
Diethyl Phthalate
Methylene Chloride
Phenol
Trichloroethene
113
113
113
113
113
113
113
113
113
113
113
112
113
1
1
7
29
62
2
4
1
24
1
1
9
6
0.096
0.013
0.011
0.010
0.010
0.051
0.157
0.013
0.010
0.049
0.011
0.010
0.010
0.096
0.013
0.281
0.030
0.081
0.102
0.190
0.013
0.026
0.049
0.011
2.00
0.021
0.096
0.013
0.106
0.018
0.025
0.076
0.176
0.013
0.016
0.049
0.011
0.264
0.016
0.096
0.013
0.053
0.018
0.022
0.076
0.178
0.013
0.016
0.049
0.011
0.022
0.017
Priority Metal Pollutants
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Cyanide
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
253
253
253
253
253
253
14
253
253
253
253
253
253
253
41
65
18
58
144
227
11
64
23
162
39
49
20
188
0.002
0.001
0.001
0.002
0.005
0.003
0.020
0.002
0.000
0.005
0.001
0.005
0.001
0.002
0.116
0.312
0.059
8,053
21.8
560
135
56.6
0.004
2,620
0.072
7.20
0.039
13,700
0.026
0.019
0.010
139
1.06
16.2
28.3
1.72
0.001
45.1
0.011
0.325
0.007
127
0.009
0.009
0.002
0.009
0.102
0.201
0.830
0.099
0.00048
0.136
0.003
0.012
0.002
0.142
Conventional Pollutants
BOD 5 -day (Carbonaceous)
112
50
1.07
873
83.0
11.6
5-27
-------
5.0 - Wastewater Characteristics
Table 5-13 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Conventional Pollutants (continued)
Oil And Grease
Oil And Grease (As HEM)
pH
Total Suspended Solids
86
111
122
250
59
28
122
157
0.295
6.23
0.25
2.00
91.0
800
13.3
6,920
9.36
58.3
6.69
141
3.80
10.9
6.84
20.0
Nonconventional Organic Pollutants
1,4-Dioxane
2-Butanone
2-Propanone
Benzoic Acid
Benzyl Alcohol
Carbon Bisulfide
Dibenzofuran
Hexanoic Acid
n,n-dimethyrformamide
n-decane
n-docosane
n-nitrosopiperidine
o-anisidine
p-cresol
Pentamethylbenzene
Safrole
Thianaphthene
Toluene, 2,4-Diamino-
Tripropyleneglycol Methyl Ether
113
113
113
113
113
113
113
113
113
113
113
113
113
113
113
113
113
113
113
2
12
8
4
2
2
1
3
5
1
1
1
1
6
1
1
1
1
1
0.132
0.066
0.052
0.126
0.014
0.062
0.010
0.013
0.025
0.012
0.012
0.020
0.025
0.014
0.036
0.085
0.010
6.56
8.48
2.02
0.550
11.5
4.31
0.014
0.354
0.010
0.332
0.115
0.012
0.012
0.020
0.025
0.063
0.036
0.085
0.010
6.56
8.48
1.08
0.195
1.59
1.63
0.014
0.208
0.010
0.147
0.045
0.012
0.012
0.020
0.025
0.038
0.036
0.085
0.010
6.56
8.48
1.08
0.124
0.071
1.05
0.014
0.208
0.010
0.096
0.028
0.012
0.012
0.020
0.025
0.040
0.036
0.085
0.010
6.56
8.48
Nonconventional Metal Pollutants
Aluminum
Barium
Boron
Calcium
Cobalt
Iron
Magnesium
Manganese
Molybdenum
253
253
253
253
253
253
253
253
253
182
208
187
245
53
193
229
163
68
0.022
0.0007
0.012
0.033
0.003
0.003
0.078
0.001
0.003
321
2.90
363
361
11.0
2,810
130
135
13.4
5.85
0.065
5.34
32.9
0.744
40.1
10.4
3.33
0.414
0.214
0.036
0.193
23.9
0.032
0.323
8.59
0.027
0.022
5-28
-------
5.0 - Wastewater Characteristics
Table 5-13 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Metal Pollutants (continued)
Sodium
Tin
Titanium
Vanadium
Yttrium
253
253
253
253
253
249
73
90
31
15
0.277
0.005
0.002
0.004
0.001
85,300
6,070
18.1
1.10
0.870
1,179
103
0.879
0.142
0.066
63.3
0.067
0.014
0.016
0.003
Other Nonconventional Pollutants
Acidity
Amenable Cyanide
Ammonia as Nitrogen
Chemical Oxygen Demand (COD)
Chloride
Fluoride
Hexavalent Chromium
Sulfate
Total Alkalinity
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbons
(As SGT-HEM)
Total Phosphorus
Total Recoverable Phenolics
Weak-acid Dissociable Cyanide
77
5
104
140
84
85
111
149
75
250
102
112
117
36
132
3
50
5
51
113
83
71
22
143
57
250
56
101
13
26
53
3
1.00
0.830
0.100
5.20
1.20
0.180
0.011
2.33
8.00
20.0
0.10
1.16
5.25
0.026
0.005
52.9
90,100
135
729
73,000
20,000
60.0
0.590
28,400
8,600
260,000
6,720
5,800
316
720
2.85
140
3,397
60.7
29.9
1,041
452
3.58
0.054
534
507
3,799
151
195
43.3
54.0
0.083
108
115
61.5
2.39
49.0
30.0
1.00
0.020
58.8
72.0
629
8.07
10.7
9.52
6.65
0.012
131
Source: MP&M sampling data.
5.5.2
General Metal-Bearing Raw Wastewater Characteristics
Typically, MP&M facilities with well-designed treatment systems segregate their
waste streams by type and treat them in preliminary treatment units designed to treat the particular
characteristic as discussed in Sections 5.1 through 5.4. After preliminary treatment, MP&M
facilities typically commingle the wastewater with general process wastewater generated from the
unit operations described in Section 5.5.1 and treat it in an end-of-pipe treatment system.
Generally, the end-of-pipe treatment consists of chemical precipitation and sedimentation. Where
high concentrations of metals are present in the wastewater, facilities may employ preliminary
batch chemical precipitation and sedimentation to ensure that the high concentrations will not
5-29
-------
5.0 - Wastewater Characteristics
cause a process upset to the end-of-pipe treatment system. Section 8.2.2 discusses metal-bearing
wastewater treatment technologies used in the MP&M industry. Table 5-14 summarizes the data
obtained from sampling the influent to end-of-pipe chemical precipitation systems. (See Section
10.0 for a discussion of achievable effluent concentrations following chemical precipitation.)
5-30
-------
5.0 - Wastewater Characteristics
Table 5-14
Analytical Data for General Metal-Bearing Treatment
Influent Wastewater Streams
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Organic Pollutants
1,1,1 -Trichloroethane
1 , 1 ,2,2-Tetrachloroethane
1 , 1 -Dichloroethene
4-Chloro-3-Methylphenol
Anthracene
Benzene
Bis(2-Chloroethyl) Ether
Bis(2-Ethylhexyl) Phthalate
Bromodichloromethane
Butyl Benzyl Phthalate
Chloroform
Chloromethane
Di-n-butyl Phthalate
Di-n-octyl Phthalate
Dibromochloromethane
Diethyl Phthalate
Ethylbenzene
Fluorene
Methylene Chloride
Naphthalene
Phenanthrene
Phenol
Tetrachloroethene
Toluene
Trichloroethene
137
137
137
136
137
137
137
137
137
137
137
137
137
137
137
134
137
137
137
137
137
139
137
137
137
6
1
2
9
1
1
1
20
14
2
63
1
3
1
6
1
5
1
10
3
3
19
8
6
3
0.019
12.1
0.011
0.011
0.104
0.025
0.016
0.008
0.011
0.009
0.010
0.011
0.007
0.012
0.014
0.038
0.006
0.045
0.008
0.012
0.041
0.016
0.015
0.009
0.019
0.084
12.1
0.748
1.14
0.104
0.025
0.016
0.298
0.143
0.010
0.824
0.011
0.066
0.012
0.065
0.038
0.335
0.045
0.172
0.054
0.112
0.634
1.11
2.77
0.023
0.053
12.1
0.379
0.183
0.104
0.025
0.016
0.051
0.026
0.009
0.102
0.011
0.044
0.012
0.024
0.038
0.074
0.045
0.043
0.035
0.071
0.099
0.306
0.533
0.021
0.053
12.1
0.379
0.076
0.104
0.025
0.016
0.014
0.016
0.009
0.032
0.011
0.058
0.012
0.016
0.038
0.010
0.045
0.023
0.038
0.060
0.029
0.081
0.019
0.021
Priority Metal Pollutants
Antimony
Arsenic
Beryllium
Cadmium
219
223
223
223
77
88
62
113
0.002
0.001
0.0002
0.001
1.13
0.530
3.23
323
0.062
0.026
0.235
6.26
0.019
0.009
0.004
0.065
5-31
-------
5.0 - Wastewater Characteristics
Table 5-14 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Priority Metal Pollutants (continued)
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Conventional Pollutants
BOD 5 -Day (Carbonaceous)
Oil And Grease (as HEM)
Total Suspended Solids
223
223
223
221
223
219
223
219
223
133
205
222
213
221
149
48
215
35
134
24
212
86
133
202
0.012
0.013
0.002
0.00003
0.012
0.001
0.005
0.001
0.009
2.40
0.570
4.00
1,350
344
159
0.012
2,101
0.090
4.23
0.112
1,540
609
32,000
8,920
15.1
16.3
3.44
0.0009
30.5
0.019
0.401
0.011
17.8
64.4
507
569
1.27
1.08
0.176
0.0003
1.52
0.007
0.046
0.002
0.945
26.0
11.9
96.8
Nonconventional Organic Pollutants
1 4-Dioxane
1-Methylfluorene
1 -Methy Iphenanthrene
2-Butanone
2-Methylnaphthalene
2-Propanone
3 , 6-Dimethy Iphenanthrene
4-Methyl-2-Pentanone
Acetophenone
Alpha-Terpineol
Aniline
Benzoic Acid
Benzyl Alcohol
Beta-Naphthylamine
Biphenyl
Carbon Disulfide
Dibenzothiophene
Diphenylamine
Hexanoic Acid
m-xylene
132
132
132
132
132
132
132
132
132
132
132
132
132
130
132
132
132
132
132
71
2
2
2
8
2
74
2
10
1
5
1
45
8
1
1
10
2
1
21
1
0.033
0.111
0.092
0.056
0.076
0.051
0.019
0.120
0.073
0.013
0.013
0.053
0.011
0.104
0.011
0.016
0.015
0.033
0.010
0.016
0.118
0.189
0.181
2.45
0.205
16.7
0.062
1.36
0.073
0.087
0.013
46.8
0.145
0.104
0.011
3.92
0.025
0.033
0.461
0.016
0.0755
0.150
0.136
0.481
0.140
0.952
0.041
0.308
0.073
0.051
0.013
1.38
0.039
0.104
0.011
0.505
0.020
0.033
0.056
0.016
0.0755
0.150
0.136
0.079
0.140
0.151
0.041
0.181
0.073
0.054
0.013
0.224
0.015
0.104
0.011
0.058
0.020
0.033
0.017
0.016
5-32
-------
5.0 - Wastewater Characteristics
Table 5-14 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Organic Pollutants (continued)
Methyl Methacrylate
n,n-dimethylformamide
n-decane
n-docosane
n-dodecane
n-eicosane
n-hexacosane
n-hexadecane
n-nitrosomethylethylamine
n-nitrosomorpholine
n-octacosane
n-octadecane
n-tetracosane
n-tetradecane
n-triacontane
o+p-xylene
o-toluidine
p-chloroaniline
p-cresol
p-cymene
Styrene
Trichlorofluoromethane
Tripropyleneglycol Methyl Ether
132
132
132
132
132
132
132
132
132
132
132
132
132
132
132
71
132
132
132
132
132
137
132
1
8
1
2
7
9
6
13
2
2
2
19
4
10
2
3
1
1
10
3
5
7
23
0.019
0.012
0.031
0.013
0.044
0.014
0.022
0.010
0.019
0.011
0.035
0.011
0.012
0.017
0.015
0.013
0.013
0.098
0.013
0.015
0.013
0.025
0.064
0.019
0.581
0.031
0.026
0.772
0.181
0.037
0.631
0.023
0.028
0.036
0.493
0.021
1.01
0.031
0.023
0.013
0.098
0.030
0.054
0.188
0.109
5.21
0.019
0.093
0.031
0.019
0.243
0.043
0.033
0.127
0.021
0.020
0.036
0.090
0.017
0.227
0.023
0.017
0.013
0.098
0.019
0.030
0.057
0.042
1.83
0.019
0.016
0.031
0.019
0.088
0.020
0.034
0.061
0.021
0.020
0.036
0.027
0.018
0.104
0.023
0.014
0.013
0.098
0.017
0.020
0.025
0.032
1.05
Nonconventional Metal Pollutants
Aluminum
Barium
Boron
Calcium
Cobalt
Gold
Iron
Magnesium
Manganese
Molybdenum
223
223
212
223
223
20
223
223
223
223
212
198
198
223
95
10
223
218
222
149
0.055
0.010
0.057
4.77
0.002
0.013
0.061
0.349
0.004
0.003
571
9.91
206
832
25.8
0.150
3,880
3,360
47.3
3.06
11.1
0.201
4.14
74.1
0.924
0.056
102
88.7
1.47
0.253
2.85
0.069
0.746
37.8
0.021
0.038
4.96
10.3
0.2315
0.039
5-33
-------
5.0 - Wastewater Characteristics
Table 5-14 (Continued)
Pollutant Parameter
No. of
Samples
Analyzed
No. of
Detects
Concentrations (mg/L)
Minimum
Maximum
Mean
Median
Nonconventional Metal Pollutants (continued)
Palladium
Sodium
Tin
Titanium
Vanadium
Yttrium
10
223
212
212
223
212
8
223
137
155
58
57
0.053
20.1
0.004
0.002
0.0016
0.00084
0.229
9,600
75.3
76.4
1.19
0.085
0.114
471
4.85
1.85
0.067
0.010
0.085
216
0.189
0.052
0.014
0.003
Other Nonconventional Pollutants
Acidity
Amenable Cyanide
Ammonia As Nitrogen
Chemical Oxygen Demand (COD)
Chloride
Fluoride
Hexavalent Chromium
Sulfate
Total Alkalinity
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbon (As SGT-HEM)
Total Phosphorus
Total Recoverable Phenolics
Total Sulfide
73
7
91
205
80
80
133
136
74
222
85
128
133
86
189
28
54
5
88
196
77
79
50
130
47
222
82
99
49
84
110
2
7.00
0.012
0.040
1.50
4.50
0.130
0.010
18.0
2.39
19.0
0.110
3.57
5.00
0.020
0.006
2.00
24,770
0.129
320
13,000
9,500
100
21.0
19,000
510
34,000
160
394
93.0
525
13.0
4.00
1,862
0.085
19.3
541
410
4.49
0.771
586
126
2,426
14.9
59.9
21.2
30.3
0.387
3.00
140
0.092
2.56
122
140
1.55
0.060
268
96.0
1,030
6.69
32.3
10.3
5.2
0.047
3.00
Source: MP&M sampling program.
5-34
-------
6.0 - Industry Subcategorization
6.0 INDUSTRY SUBCATEGORIZATION
This section discusses the Subcategorization of the MP&M Point Source Category.
Section 6.1 discusses the methodology and factors considered when determining the subcategories and
Section 6.2 describes facilities in each subcategory.
6.1 Methodology and Factors Considered for Basis of Subcategorization
To provide a method for addressing variations between products, raw materials
processed, and other factors that result in distinctly different effluent characteristics, EPA divided the
MP&M Point Source Category into groupings called "subcategories." Each subcategory has a uniform
set of effluent limitations that take into account technological achievability and economic impacts unique
to that subcategory. The Clean Water Act (CWA) requires EPA, in developing effluent limitations
guidelines and pretreatment standards, to consider a number of different Subcategorization factors. The
statute also authorizes EPA to take into account other factors the Agency deems appropriate. EPA
considered the following factors in its evaluation of potential MP&M subcategories:
• Unit operation;
• Activity;
• Raw materials;
• Products;
• Size of site;
• Geographic location;
• Facility age;
• Nature of the waste generated;
• Economic impacts;
• Treatment costs;
• Total energy requirements;
• Air pollution control methods;
• Solid waste generation and disposal; and
• Publicly Owned Treatment Works (POTW) burden.
As a result, EPA has determined that a basis exists for dividing the MP&M category
into the following subcategories for the proposed rule, as shown in Table 6-1.
6-1
-------
6.0 - Industry Subcategorization
Table 6-1
Proposed Subcategories
Facilities that Generate Metal-Bearing Wastewater
(With or Without Oil-Bearing Wastewater)
Facilities that Generate Only Oil-Bearing
Wastewater
General Metals
Metal Finishing Job Shops
Non-Chromium Anodizing
Printed Wiring Board
Steel Forming and Finishing
Oily Wastes
Railroad Line Maintenance
Shipbuilding Dry Dock
6.1.1
Factors Contributing to Subcategorization
EPA found two basic types of waste streams in the industry: 1) wastewater with high
metals content (metal-bearing), and 2) wastewater with low concentration of metals, and high oil and
grease content (oil-bearing). The type of wastewater a facility generates is directly related to the unit
operations it performs. For example, unit operations such as machining, grinding, aqueous degreasing,
and impact or pressure deformation tend to generate a wastewater with high oil and grease (and
associated organic pollutants) loadings but relatively lower concentrations of metal pollutants. Other
unit operations such as electroplating, conversion coating, chemical etching and milling, and anodizing
generate higher metals loadings with moderate or low oil and grease concentrations or generate
wastewater containing both metals and oil and grease.
Although many facilities generate both metal- and oil-bearing wastewater, a large
number of facilities, typically machine shops and maintenance and repair facilities, only generate oil-
bearing wastewater. Since the wastewater at these facilities primarily contains oil and grease and other
organic constituents, these facilities use treatment technologies that focus on oil removal only and do not
include the chemical precipitation step needed to treat metal-bearing wastewater. These treatment
technologies generally include ultrafiltration, or chemical emulsion breaking followed by either gravity
flotation, coalescing plate oil/water separators, or dissolved air flotation (DAF). Therefore, EPA first
divided the industry on the basis of unit operations performed and the nature of the wastewater
generated, resulting in the following two groups: (1) metal-bearing with or without oily and organic
constituents group; and (2) oil-bearing only group. EPA then performed an analysis to identify any
significant differences in the Subcategorization factors within the two basic groups. Section 6.2.6
identifies the unit operations that EPA believes to generate only oil-bearing wastewater to generate
metal-bearing wastewater. EPA considers MP&M facilities that perform MP&M unit operations other
than those mentioned in Section 6.2.6 to generate metal-bearing wastewater.
6-2
-------
6.0 - Industry Subcategorization
Metal-Bearing Wastewater (With or Without Oil-Bearing Wastewater)
When looking at facilities generating metal-bearing wastewater (with or without oil-
bearing wastewater), EPA identified five groups of facilities that could potentially be subcategorized by
dominant product, raw materials used, and/or nature of the waste generated. In two groups, EPA also
considered economic impacts as a factor in Subcategorization because of the reduced ability of these
facilities to afford treatment costs. Within the group of facilities with metal bearing wastewater EPA
also identified one group where the number of facilities not currently covered by an existing effluent
guidelines regulation was large enough to present an unacceptable burden to POTWs.
Based on the currently available data, EPA divided the metal-bearing (with or without
oil-bearing wastewater) MP&M facilities into the following subcategories: non-chromium anodizing
facilities; metal finishing job shops; printed wiring board facilities; steel forming and finishing facilities;
and general metals facilities. EPA describes its rationale for subcategorizing each of these groups
below (see Section 6.2 for additional detailed discussion and applicability).
The non-chromium anodizers differ from other MP&M facilities in that all of their
products are primarily of one metal type, anodized aluminum, and most importantly, they do not use
chromic acid, dichromate sealants, or other process solutions containing significant concentrations of
chromium in their anodizing process. Based on EPA's limited data for these facilities, the Agency
expects that these facilities have very low levels of metals (with the exception of aluminum) or toxic
organic pollutants in their wastewater discharges. EPA determined that other MP&M facilities had
much greater concentrations of a wider variety of metals. Table 6-2 illustrates this point by providing
the percentage of facilities using multiple metal types by subcategory.
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6.0 - Industry Subcategorization
Table 6-2
Percentage of Facilities Using Multiple Metal Types by Subcategory
Proposed Subcategory
Shipbuilding Dry Docks
General Metals
Steel Forming and Finishing
Metal Finishing Job Shop
Non- Chromium Anodizer
Oily Wastes
Printed Wiring Boards
Railroad Line Maintenance
Number of Metal Types Processed
0
0
0
0
0
0
32
0
<1
1
0
51
55
7
76
13
1
98
2
25
23
25
24
24
53
0
1
3
50
13
14
23
0
1
49
<1
4
0
4
3
4
0
<1
9
0
5-
10
25
10
3
41
0
0
40
0
>10
0
0
0
1
0
0
1
0
Source: MP&M Survey Database
In addition, non-chromium anodizing facilities require much larger wastewater treatment
systems than other metal-bearing MP&M facilities to remove the large amounts of aluminum and low
levels of alloy metals generated in their wastewater. The need for larger treatment systems results in
higher costs and large economic impacts for this proposed Subcategory. EPA found that as many as 60
percent of the non-chromium anodizers could close as a result of complying with the regulatory options
considered.
Therefore, based on the difference in raw materials used, product produced, nature of
the waste generated (i.e., low levels of pollutants discharged), treatment costs, and projected economic
impacts, EPA concluded that a basis exists for subcategorizing the non-chromium anodizing facilities in
the MP&M industry.
EPA investigated whether to subcategorize the metal finishing and electroplating job
shops covered currently by the metal finishing (40 CFR 433) and electroplating (40 CFR 413) effluent
guidelines. Although these facilities have metal types that require the same treatment technologies as
many other metal-bearing facilities, EPA determined that they can be different due to the variability of
their raw materials and products as well as the slightly higher economic impacts incurred as compared
to other MP&M facilities. As discussed in Section 6.2, this Subcategory includes only those facilities
that perform the six operations defining the applicability of the metal finishing and electroplating effluent
guidelines and that are "job shops" as defined in the metal finishing effluent guidelines (i.e., they own less
than 50 percent of the products processed on site on an annual area basis).
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6.0 - Industry Subcategorization
Because these facilities are job shops and work on a contract basis, they cannot always
predict the type of plating or other finishing operations required. In addition, because these facilities
work on a large variety of metal types from various customers, their wastewater characteristics can
vary from week to week (or even day to day). Table 6-2 demonstrates the variety of metal types
processed at metal finishing job shops as compared to the rest of the industry. (Note that shipbuilding
dry docks and printed wiring board facilities also process a wide variety of metal types. EPA also
chose to subcategorize these groups for reasons discussed below.) EPA performed sampling to
specifically identify the variability in the wastewater generated at metal finishing job shops, and found
that the variability factors calculated solely on the analytical wastewater sampling data from metal
finishing and electroplating job shops are higher for most pollutant parameters than those calculated for
similar metal-bearing subcategories (e.g., General Metals) (see Section 10.1 for a discussion of EPA's
job shop variability wastewater sampling and Section 10.3 for a discussion on determining limits and
variability factors). In addition, EPA found that up to 10 percent of the indirect discharging metal
finishing job shops could close as a result of compliance with the proposed regulation. Therefore, EPA
concluded that it has an appropriate basis for subcategorizing metal finishing and electroplating job
shops.
EPA determined that there is a basis for subcategorizing the printed wiring board
facilities based on raw materials, unit operations performed, primary product, and nature of the waste
generated. First, as shown in Table 6-3, these facilities process a more consistent mix of metal types
(primarily copper, tin, and lead) than other metal-bearing wastewater generating MP&M facilities.
EPA concluded that this consistent mix of metal types enables printed wiring board facilities to tailor
their treatment technology and incorporate more of the advanced pollution prevention and recovery
technologies (e.g., ion exchange).
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6.0 - Industry Subcategorization
Table 6-3
Percentage of MP&M Facilities by Subcategory Using Each Metal Type
Metal
Aluminum
Beryllium
Cadmium
Chromium
Cobalt
Copper
Gold
Indium
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Palladium
Platinum
Rhodium
Ruthenium
Selenium
Silver
Tantalum
Tin
Titanium
Tungsten
Yttrium
Zinc
Zirconium
Subcategory
Shipbuilding
Dry Docks
25
0
25
50
0
75
0
0
100
0
0
0
25
75
0
0
0
0
0
25
0
0
0
0
0
25
0
General
Metals
38
0
1
6
3
28
4
0
82
4
2
0
0
13
1
0
0
0
0
2
1
11
3
1
0
14
0
Steel
Forming
and
Finishing
3
0
3
11
3
10
0
0
100
1
0
0
0
5
0
0
0
0
0
0
0
5
3
0
0
30
0
Metal
Finishing
Job Shop
60
1
11
27
0
53
14
0
87
9
5
0
0
53
0
1
6
0
0
16
0
30
3
0
1
54
0
Non-
Chromium
Anodizer
88
0
0
0
0
0
0
0
36
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Oily
Wastes
46
0
0
1
1
12
0
0
86
1
2
0
0
6
0
0
0
0
0
0
0
0
1
1
0
1
0
Printed
Wiring
Boards
6
0
0
3
1
99
82
0
11
94
0
2
6
82
7
0
1
1
0
11
0
97
0
0
8
3
0
Railroad
Line
Maintenance
1
0
0
0
0
6
0
0
100
6
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Source: MP&M Survey Database
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6.0 - Industry Subcategorization
Printed wiring board facilities generally work with copper-clad laminate material,
allowing them to target copper for removal in their wastewater treatment systems or recover the copper
using in-process ion exchange. Second, these facilities apply, develop, and strip photo resist - a set of
unit operations that is unique to this subcategory. This process produces a higher concentration of a
more consistent group of organic constituents than other facilities in the metal-bearing group. Finally,
the nature of the wastewater generated at these facilities may also be different because these facilities
perform more lead-bearing operations (e.g., lead/tin electroplating, wave soldering) than other MP&M
facilities.
Steel forming and finishing is another proposed subcategory under the metal- bearing
group of MP&M facilities. These facilities perform both cold forming and finishing operations on steel
at stand-alone facilities as well as at steel manufacturing facilities. EPA formerly covered these facilities
under the 1982 Iron and Steel Manufacturing effluent guidelines (40 CFR Part 420). Typical
operations include: acid pickling, annealing, conversion coating (e.g., zinc phosphate, copper sulfate),
hot dip coating and/or electroplating of steel wire or rod, heat treatment, welding, drawing, patenting,
and oil tempering. EPA concluded that the basis for Subcategorization is the difference in the raw
material and primary product at these facilities. Facilities in this subcategory primarily process steel
and, for the most part, produce uniformly shaped products such as wire, rod, bar, pipe, and tube. In
addition, this is the only subcategory for which EPA is proposing to cover forming operations under the
MP&M regulations. Effluent guidelines specific to forming operations exist for all other common metal
types (e.g., Aluminum Forming (40 CFR Part 467); Copper Forming (40 CFR Part 468); and
Nonferrous Metals Forming & Metal Powders (40 CFR Part 471)).
After subcategorizing non-chromium anodizing facilities, metal finishing job shops,
printed wiring board facilities, and steel forming and finishing facilities, EPA is proposing to group the
remaining metal-bearing wastewater generating MP&M facilities into a subcategory entitled "General
Metals." This subcategory would be a "catch-all" for metal-bearing wastewater generating facilities that
do not fall into any of the previous subcategories. For example, wastewater generated from most
manufacturing operations and heavy rebuilding operations (e.g., aircraft, aerospace, auto, bus/truck,
railroad) would be regulated under the proposed General Metals subcategory. Whereas all facilities in
the other four metal-bearing subcategories are currently covered by existing effluent guidelines, only 16
percent of General Metals facilities are covered by 433/413 (with another 10 percent having some
waste streams covered by other metals, effluent guidelines). This means that over 25,000 MP&M
facilities in this subcategory would require new permits (i.e. control mechanisms). EPA recognizes that
this would create a very large burden on POTWs. Therefore, in determining a proposed option for the
General Metals Subcategory, EPA considered the POTW permitting burden associated with proposing
pretreatment standards for over 25,000 facilities (See Section 14.0).
Oil-Bearing Only Group
When evaluating facilities with only oil-bearing wastewater for potential further
Subcategorization, EPA identified two types of facilities that were different from the other facilities in
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6.0 - Industry Subcategorization
that group based on size, location, and dominant product or activity. The first type of facility is railroad
line maintenance facilities, and the second performs MP&M operations in shipbuilding dry docks or
similar structures (see Section 6.2.7 and 6.2.8, respectively, for detailed descriptions of these proposed
subcategories).
Railroad line maintenance facilities perform outdoor light maintenance and cleaning of
railroad cars, engines, and wheel trucks. EPA concluded that there is a basis to subcategorize railroad
line maintenance facilities due to their outdoor location, unit operations performed, and low level of
pollutant loadings discharged to the environment. Unit operations typically performed at railroad line
maintenance facilities include: abrasive blasting, alkaline cleaning for oil removal, aqueous degreasing,
assembly/disassembly, floor cleaning, washing finished products, welding, and collection of storm
water. EPA notes that this proposed subcategory does not include railroad manufacturing facilities or
railroad overhaul/rebuilding facilities.
The second type of facility is dry docks (and similar structures such as graving docks,
building ways, lift barges, and marine railways): large, outdoor areas, exposed to precipitation, where
shipyards perform final assembly, maintenance, rebuilding, and repair work on large ships and boats.
EPA believes that a basis exists to subcategorize shipbuilding dry docks and similar structures due to
their size, outdoor location, low level of pollutant loadings discharged to the environment, and the fact
this wastewater is unique to the shipbuilding industry. This proposed subcategory does not include
other MP&M operations that occur at shipyards (e.g., shore-side operations).
The facilities that generate only oil-bearing wastewater but are not dry docks or
railroad line maintenance facilities fall into the Oily Wastes Subcategory. These facilities discharge only
oil-bearing wastewater and perform only one or more of the unit operations listed in Table 6-4 below.
Table 6-4
Unit Operations Performed by Oily Wastes Facilities
Alkaline Cleaning for Oil Removal
Aqueous Degreasing
Corrosion Preventive Coating
Floor Cleaning
Grinding
Heat Treating
Impact Deformation
Machining
Pressure Deformation
Solvent Degreasing
Testing (e.g., Hydrostatic, Dye Penetrant, Ultrasonic, Magnetic Flux)
Painting
Steam Cleaning
Laundering
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6.0 - Industry Subcategorization
Therefore, EPA divided the facilities in the MP&M industry that generate only oil-
bearing wastewater into the following three subcategories: (1) railroad line maintenance facilities; and
(2) shipbuilding dry docks (and similar structures); (3) oily waste facilities. Following further analysis,
EPA decided not to propose pretreatment standards for indirect dischargers in the railroad line
maintenance and shipbuilding dry dock subcategories and proposed a low flow cutoff of 2 million
gallons per year for indirect dischargers in the Oily Wastes Subcategory. (see Section 14.8 for a
discussion pertaining to pretreatment standards).
6.1.2 Factors That are not a Basis for MP&M Subcategorization
EPA examined the other factors listed earlier in this section for possible basis of
Subcategorization. The Agency determined that there is no basis for subcategorizing the MP&M
industry based on the following factors: geographic location, age of facilities, total energy requirements,
air pollution control methods, and solid waste generation and disposal. These factors are discussed
below. In addition, EPA also considered subcategorizing the MP&M industry according to the 18
industrial sectors listed in Section 2.2.5. As discussed in Section 6.1.1, and further discussed below,
EPA determined that Subcategorization based on sectors was appropriate for only one sector (printed
wiring board), and for portions of three other sectors (railroad, ships and boats, and job shops).
Geographic Location
MP&M sites are located throughout the United States. Sites are not limited to any one
geographical location, but approximately half are located east of the Mississippi, with additional
concentrations of sites in Texas, Colorado, and California. EPA did not subcategorize based on
geographic location because location does not affect the ability of sites to comply with the MP&M rule.
Geographic location may impact costs if additional land is required to install treatment
systems, since the cost of the land will vary depending on whether the site is located in an urban or rural
location. However, the treatment systems used to treat MP&M wastewater typically do not have large
land requirements, as demonstrated by the fact that many MP&M sites are located in urban settings.
Water availability is another function of geographical location. Limited water supply
encourages efficient use of water. The Agency encourages installing water recycle and reuse practices.
The proposed treatment options for all subcategories include pollution prevention and water
conservation because these practices tend to reduce treatment costs and improve pollutant removals.
Facility Age
The percentage of water-discharging facilities by the decade in which they were built is
shown in Figure 6-1. This information is based upon responses to MP&M surveys that reported the
date the facility was built.
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6.0 - Industry Subcategorization
Source: MP&M Survey Database.
Note: MP&M surveys were mailed in 1991 and 1996. There are 62,749 wastewater-discharging MP&M sites.
Figure 6-1. Percentage of Wastewater-Discharging Facilities by Decade Built
Most sites have been built since 1970. Although the survey respondents reported a
wide range of ages, these sites must be continually modernized to remain competitive. Most of the sites
EPA visited during the MP&M site visit program had recently modernized some area of their site.
Modernizing production processes and air pollution control equipment results in generation of similar
wastes among all sites of various ages. Therefore, EPA did not select facility age as a basis for
Subcategorization.
Total Energy Requirements
EPA did not select total energy requirements as a basis for Subcategorization because
EPA does not expect energy requirements to vary widely on a production normalized basis. The
Subcategorization scheme that EPA is proposing should account for any variations in energy
requirements (e.g., differences in treatment system energy requirements for metal-bearing streams
versus oily waste streams). The estimated impacts of this regulation on energy consumption in the
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6.0 - Industry Subcategorization
United States is an energy increase of approximately 0.01 percent (see Section 13.0). EPA estimated
the energy requirements associated with each MP&M technology option and considered these in
estimating compliance costs (see Section 11.0).
Air Pollution Control Methods
Many sites control air emissions using wet air pollution control units that affect the
wastewater flow rate from the site. However, based on data collected during the MP&M sampling
program, wastewater generated by these devices does not affect the effectiveness of technologies used
to control MP&M wastewater pollutant loadings. EPA considers wet air pollution control units
additional unit operations within the MP&M category, but not as a basis of subcategorizing the
category.
Industrial Sectors
EPA considered subcategorizing the MP&M category by industrial sector (e.g.,
aerospace, aircraft, bus and truck, electronic equipment, hardware, household equipment, instruments,
job shops, mobile industrial equipment, motor vehicles, office machines, ordnance, precious metals and
jewelry, printed wiring boards, railroad, ships and boats, stationary industrial equipment, and
miscellaneous metal products). Sectors are broadly defined and not only include manufacturing and
repair facilities within the sector (e.g., shipbuilding facilities in the ship and boat sector), but also include
facilities that produce products that are used within the sector (e.g., a facility that manufactures
hydraulic pumps used on ships is also in the ship and boat sector). The Agency determined that
Subcategorization based solely on industrial sector would require much more detailed Subcategorization
scheme than the approach proposed (see below). Adopting a Subcategorization scheme based on
industrial sector would complicate the implementation of the limitations and standards because permit
writers might be required to develop facility-specific limitations across multiple subcategories.
The Agency determined that wastewater characteristics, unit operations, and raw
materials used to produce products within a given sector are not always the same from site to site, and
they are not always different from sector to sector. Within each sector, sites can perform a variety of
unit operations on a variety of raw materials. For example, a site in the aerospace sector may primarily
machine aluminum missile components and not perform any surface treatment other than alkaline
cleaning. Another site in that sector may electroplate iron parts for missiles and perform little or no
machining. Wastewater characteristics from these sites may differ because of the different unit
operations performed and different raw materials used.
Based on the analytical data collected for this rule, EPA has not found a statistically
significant difference in industrial wastewater discharge among industrial sectors when performing similar
unit operations for cadmium, chromium, copper, cyanide, lead, manganese, molybdenum, nickel, oil &
grease, silver, tin, TSS, and zinc. (The analytical data are available in the public record for this
rulemaking.) For example, a facility that performs electroplating in the process of manufacturing office
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6.0 - Industry Subcategorization
machines produces metal-bearing wastewater with similar chemical characteristics as a facility that
performs electroplating in the process of manufacturing a part for a bus. Similarly, a facility that
performs repair and maintenance on a airplane engine produces oil-bearing wastewater that has similar
chemical characteristics to a facility that performs repair and maintenance on construction machinery.
Most MP&M unit operations are not unique to a particular sector and are performed
across all sectors. For example, all sectors may perform several of the major wastewater-generating
unit operations (e.g., alkaline treatment, acid treatment, machining, electroplating). And, for the most
part, the unit operations that are rarely performed (e.g., abrasive jet machining) are not performed in all
sectors, but are also not limited to a single sector. Therefore, a facility in any one of the 18 industrial
sectors can generate metal-bearing or oil-bearing wastewater (or a combination of both) depending on
what unit operations the facility performs.
In addition, two facilities that may be part of the same sector may generate wastewater
with vastly different chemical characteristics and thus require different types of treatment. For example,
an automobile manufacturer and an automobile repair facility are both part of the motor vehicle sector.
However, the automobile manufacturer may perform unit operations that generate metal-bearing and
oil-bearing wastewater (aqueous degreasing, electroplating, chemical conversion coating, etc.) while the
automobile repair facility may perform unit operations that only generate oil-bearing wastewater
(machining, aqueous degreasing, impact deformation, painting, etc.).
Due to the numerous MP&M facilities that could fall under the scope of multiple
sectors, EPA determined that a regulation based on MP&M industrial sector would create a variety of
implementation issues for State and local regulators as well as for those multiple-sector facilities.
Therefore, as mentioned above, EPA is not proposing to use industrial sector to subcategorize the
industry.
After dividing facilities in the MP&M industry according to the unit operations
performed (metal-bearing or oil-bearing operations), EPA concluded that raw wastewater has similar
treatability across all of the MP&M sectors. Therefore, a facility that performs electroplating in the
process of manufacturing office machines produces metal-bearing wastewater with similar chemical
characteristics as a facility that performs electroplating in the process of manufacturing a part for a bus.
Similarly, a facility that performs repair and maintenance on an airplane engine produces oil-bearing
wastewater that has similar chemical characteristics to a facility that performs repair and maintenance on
construction machinery.
Solid Waste Generation and Disposal
Physical and chemical characteristics of solid waste generated by the MP&M category
are determined by the raw materials, unit operations, and types of air pollution control in use.
Therefore, this factor does not provide a primary basis for Subcategorization. The Subcategorization
scheme that EPA is proposing should account for any variations in solid waste generated or disposed.
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6.0 - Industry Subcategorization
EPA considered the amount of sludge generated as a result of the MP&M technology options, and
included disposal of these sludges in the compliance cost estimates (see Section 11.0) and non-water
quality impact assessments (see Section 13.0).
6.2 General Description of Facilities in Each Subcategory
Below is a general description of the types of facilities that fall within each of the
proposed subcategories. Sections 11.0 and 12.0 present information on compliance costs and
pollutant reductions associated with the MP&M proposed rule for each subcategory
6.2.1 General Metals Subcategory
As discussed above in Section 6.1, EPA has created the General Metals Subcategory
as a "catch-all" for MP&M facilities that discharge metal-bearing wastewater (with or without oil-
bearing wastewater) that do not fit the applicability of the Metal Finishing Job Shops, Non-Chromium
Anodizing, Printed Wiring Board, or Steel Forming and Finishing Subcategories. Therefore, the
General Metals Subcategory may include facilities from 17 of the 18 MP&M industrial sectors (i.e., all
except the printed wiring board sector). This subcategory also includes general metals facilities that are
owned and operated by states and municipalities. General metals facilities typically perform
manufacturing or heavy rebuilding of metal products, parts, or machines. Facilities that perform metal
finishing or electroplating operations on site, but do not meet the definition of a job shop (i.e., captive
shops), would fit in the General Metals Subcategory.
EPA estimates that there are approximately 26,000 indirect dischargers and 3,800
direct dischargers that could be covered by this Subcategory. EPA currently regulates 26 percent of
the facilities in this subcategory by existing effluent guidelines. The Agency estimates that, based on
responses to its questionnaires, the Metal Finishing (40 CFR 433) and Electroplating (40 CFR 413)
effluent guidelines cover approximately 16 percent of these facilities, and other metal related effluent
guidelines (such as those discussed in Section 1.2.7. cover a portion of the wastewater discharges at an
additional 10 percent of these facilities.
EPA is proposing to exclude from the MP&M regulations indirect dischargers that
would fall into the General Metals Subcategory when they discharge less than or equal to 1 million
gallons per year (MGY) of MP&M process wastewater to the POTW (see Section 14.0 for EPA's
discussion of flow cutoffs). Approximately 23,000 indirect dischargers in the General Metals
Subcategory discharge less than 1 MGY. If EPA did not exclude these facilities, the number of permits
that POTWs would issue would double, greatly increasing their burden. Facilities discharging less than
1 MGY to a POTW, however, are still subject to other applicable pretreatment standards, including
those established under 40 CFR Parts 413 and 433.
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6.0 - Industry Subcategorization
6.2.2 Metal Finishing Job Shops Subcategory
Facilities in the Metal Finishing Job Shops Subcategory must meet the following criteria:
(1) perform one or more of the following 6 operations: electroplating, electroless plating, anodizing,
coating (chromating, phosphating, passivation, and coloring), chemical etching and milling, and printed
circuit board manufacture and (2) own not more than 50 percent (on an annual area basis) of the
materials undergoing metal finishing. EPA is proposing to include printed wiring board job shops in this
Subcategory based on the unique economics of job shop operation.
The Agency estimates that there are approximately 1,500 indirect dischargers and 15
direct dischargers in the proposed Metal Finishing Job Shops Subcategory. EPA currently regulates all
facilities in this Subcategory under the existing Metal Finishing or Electroplating effluent guidelines and
standards. EPA is proposing to cover all of these facilities under MP&M. Therefore, facilities subject
to the Metal Finishing Job Shops Subcategory will no longer be covered by the effluent guidelines and
standards in 40 CFR 413 or 40 CFR 433.
EPA has identified approximately 30,000 facilities that meet the definition of job shop
but do not perform one or more of the six metal finishing operations as defined in 40 CFR 433. EPA
does not consider such job shops to be part of the Metal Finishing Job Shops Subcategory. These
other job shops typically perform assembly, painting, and machining on a contract basis and are likely
to fall in the General Metals or Oily Waste Subcategories.
6.2.3 Non-Chromium Anodizing Subcategory
Facilities covered under the Non-Chromium Anodizing Subcategory must perform
aluminum anodizing without using chromic acid or dichromate sealants. Anodizing is a surface
conversion operation used to alter the properties of aluminum for better corrosion resistance and heat
transfer. Generally, non-chromium anodizing facilities perform sulfuric acid anodizing; however,
facilities can use other acids, such as oxalic acid, for aluminum anodizing. EPA will cover anodizers that
use chromic acid or dichromate in the General Metals Subcategory or, if they operate as a job shop, in
the Metal Finishing Job Shops Subcategory.
EPA estimates that there are approximately 190 indirect dischargers and, to date, has
not identified any direct dischargers in the Non-Chromium Anodizing Subcategory. The wastewater
generated at non-chromium anodizing facilities contains very low levels of metals (with the exception of
aluminum) and toxic organic pollutants. In addition, EPA determined that compliance with one of the
regulatory options that EPA considered proposing would cause 60 percent of the indirect dischargers in
this Subcategory to close. For the reasons discussed in detail in Section 14.0, EPA is proposing to
exclude wastewater from indirect discharging non-chromium anodizing facilities from the MP&M
categorical pretreatment standards. Such facilities will still need to comply with the Metal Finishing (40
CFR 433) pretreatment standards for their non-chromium anodizing wastewater and the general
pretreatment standards at 40 CFR Part 403.
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6.0 - Industry Subcategorization
Some facilities that could potentially fall into the Non-Chromium Anodizing
Subcategory may also perform other metal surface finishing operations. If these facilities commingle
their wastewater from their non-chromium anodizing operations with wastewater from other surface
finishing operations (e.g., chromic acid anodizing, electroplating, chemical conversion coating) for
treatment, they will not be covered by the Non-Chromium Anodizing Subcategory. Instead, the
General Metals or Metal Finishing Job Shop Subcategories would apply. However, for facilities that
discharge their non-chromium anodizing wastewater separately from their other surface finishing
wastewater, control authorities (e.g., POTWs) and permit writers would apply the appropriate limits to
each discharge.
6.2.4 Printed Wiring Board Subcategory
The Printed Wiring Board Subcategory will cover wastewater discharges from the
manufacture, maintenance, and repair of printed wiring boards (i.e., circuit boards). This Subcategory
does not include job shops that manufacture, maintain, or repair printed wiring boards; EPA is covering
these facilities under the Metal Finishing Job Shops Subcategory, as discussed in Section 6.3.2. EPA
currently regulates all facilities in this Subcategory by the existing Metal Finishing or Electroplating
effluent guidelines and standards, but will cover all of these facilities under MP&M. Therefore, facilities
subject to the Printed Wiring Board Subcategory will no longer be covered by the effluent limitations
guidelines and standards in 40 CFR 413 or 40 CFR 433. Printed wiring board facilities perform unique
operations, including applying, developing and stripping of photo resist, lead/tin soldering, and wave
soldering. EPA estimates that there are approximately 620 indirect dischargers and 11 direct
dischargers in the proposed Printed Wiring Board Subcategory.
6.2.5 Steel Forming and Finishing
Although many facilities may perform MP&M operations with steel, EPA has
established the Steel Forming and Finishing Subcategory for facilities that perform MP&M operations
(listed in Section 4.4) and/or cold forming operations on steel wire, rod, bar, pipe, or tube. This
Subcategory does not include facilities that perform those operations on other base materials. In a
separate notice, EPA has proposed to revise the Iron and Steel Manufacturing effluent guidelines. The
proposed revisions to the Iron and Steel regulations exclude those facilities that EPA has determined to
be appropriately regulated by the MP&M rule. EPA based this decision on the information gathered
during the data collection effort for the revision to the Iron and Steel Manufacturing regulations.
The MP&M Steel Forming and Finishing Subcategory does not cover wastewater
generated from any hot steel forming operations, or from cold forming, electroplating, or continuous hot
dip coating of steel sheet, strip, or plates. As mentioned above, the proposed Iron and Steel
Manufacturing effluent guidelines will cover wastewater from such operations.
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6.0 - Industry Subcategorization
There are approximately 110 indirect dischargers and 43 direct dischargers in the Steel
Forming and Finishing Subcategory. All facilities in this subcategory have permits or other control
mechanisms under the existing Iron and Steel Manufacturing regulation (40 CFR 420).
EPA is proposing to cover wastewater from these steel forming and finishing
operations, regardless of whether they occur at a stand-alone facility or at a steel manufacturing facility.
When a steel manufacturing facility performs these MP&M steel forming and finishing operations and
commingles the wastewater for treatment with wastewater from other non-MP&M unit operations,
control authorities and permit writers will need to set limits that account for both the MP&M and the
Iron and Steel regulations. EPA refers to this approach as the combined waste stream formula or the
building block approach. For facilities that choose to discharge their MP&M steel forming and finishing
wastewater separate from their iron and steel wastewater, control authorities and permit writers will
apply the appropriate limits to each discharge.
6.2.6 Oily Wastes Subcategory
EPA has created the Oily Wastes Subcategory as a "catch-all" for MP&M facilities
that discharge only oil-bearing wastewater and that do not fit the applicability of the other MP&M
subcategories. EPA is defining the applicability of this subcategory by the presence of specific unit
operations. Facilities in the Oily Wastes Subcategory must not fit the applicability of the Railroad Line
Maintenance or Shipbuilding Dry Dock Subcategories and must only discharge wastewater from one or
more of the following MP&M unit operations: alkaline cleaning for oil removal, aqueous degreasing,
corrosion preventive coating, floor cleaning, grinding, heat treating, impact deformation, machining,
pressure deformation, solvent degreasing, testing (e.g., hydrostatic, dye penetrant, ultrasonic, magnetic
flux), painting, steam cleaning, and laundering. Facilities in this subcategory are predominantly machine
shops or maintenance and repair shops. EPA has defined "corrosion preventive coating" as the
application of removable oily or organic solutions to protect metal surfaces against corrosive
environments. Corrosion preventive coatings include, but are not limited to: petroleum compounds,
oils, hard dry-film compounds, solvent-cutback petroleum-based compounds, emulsions, water-
displacing polar compounds, and fingerprint removers and neutralizers. Corrosion preventive coating
does not include electroplating, painting, and chemical conversion coating (including phosphate
conversion coating) operations. Based on EPA's analytical database for this proposal, EPA believes
that wastewater generated from phosphate conversion coating operations contains high levels of zinc
and manganese.
If a facility discharges wastewater from any of the operations listed above but also
discharges wastewater from other MP&M operations (listed in Section 4.4), it does not meet the
criteria of the Oily Wastes Subcategory. EPA has determined that other MP&M unit operations
generate metal-bearing wastewater or combination metal- and oil-bearing wastewater and require
different treatment technologies (e.g., chemical precipitation). EPA included wastewater from floor
cleaning and testing operations in the Oily Wastes Subcategory after confirming through a review of the
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6.0 - Industry Subcategorization
analytical data that there is little or no metals content in these two streams. This subcategory also
includes municipal and state-owned facilities performing only the listed operations.
Like the General Metals Subcategory, the Oily Wastes Subcategory may include
facilities from 17 of the 18 MP&M industrial sectors (i.e., all except the printed wiring board sector).
EPA estimates that there are approximately 28,500 indirect dischargers and 900 direct
dischargers in the Oily Wastes Subcategory. EPA has concluded that less than 1 percent of the
MP&M process wastewater discharged from these facilities in this subcategory is covered by existing
effluent guidelines.
In an effort to relieve administrative burden on POTWs that will implement the MP&M
regulation, EPA is proposing to exclude from the MP&M regulations indirect dischargers that would fall
into the Oily Wastes Subcategory when they discharge less than or equal to 2 MGY of MP&M
process wastewater to the POTW. (See Section 14.0 for a discussion of the low-flow exclusion for
indirect dischargers in the Oily Waste Subcategory.)
6.2.7 Railroad Line Maintenance Subcategory
EPA has developed the Railroad Line Maintenance Subcategory to cover facilities that
perform routine cleaning and light maintenance (mostly consisting of parts replacement) on railroad
engines, cars, car-wheel trucks, and similar parts or machines. More specifically, these facilities
discharge wastewater from only those MP&M unit operations that EPA defines as oily operations (see
Section 6.2.6, above), storm water clean-up (which is not covered by the proposed regulation), and/or
washing of final products. EPA considers "washing of final product" an MP&M "oily" operation for
this subcategory. The Agency reviewed the analytical wastewater sampling data for this waste stream
at railroad line maintenance facilities and determined that there is little or no metal content. However,
for other primarily oily subcategories (oily wastes and shipbuilding dry docks), EPA does not consider
this unit operation an MP&M "oily" operation. Railroad line maintenance facilities are similar to
facilities in the Oily Wastes Subcategory in that they produce oil-bearing wastewater and do not
perform MP&M operations that generate wastewater that requires metals removal treatment
technology. This subcategory does not include railroad manufacturing facilities or railroad overhaul or
heavy maintenance facilities.
EPA estimates that there are approximately 800 indirect dischargers and 35 direct
dischargers in the Railroad Line Maintenance Subcategory. The wastewater generated at railroad line
maintenance facilities contains very low levels of metals and toxic organic pollutants._EPA is proposing
to exclude wastewater from indirect discharging railroad line maintenance facilities from the MP&M
regulations. (See Section 14.0 for a discussion on the rationale for this exclusion). However, EPA is
proposing to regulate conventional pollutants for direct dischargers in this subcategory.
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6.0 - Industry Subcategorization
6.2.8 Shipbuilding Dry Dock Subcategory
EPA has created the Shipbuilding Dry Dock Subcategory to specifically cover MP&M
process wastewater generated in or on dry docks and similar structures such as graving docks, building
ways, marine railways, and lift barges at shipbuilding facilities (or shipyards). Shipbuilding facilities use
these structures to maintain, repair, or rebuild existing ships, or perform the final assembly and launching
of new ships (including barges). Shipbuilders use these structures to reach surfaces and parts that
would otherwise be under water. Since dry docks and similar structures include sumps or containment
systems, shipyards can control the discharge of pollutants to surface water. Typical MP&M operations
that occur in dry docks and similar structures include abrasive blasting, hydro blasting, painting,
welding, corrosion preventive coating, floor cleaning, aqueous degreasing, and testing (e.g., hydrostatic
testing). Not all of these unit operations generate wastewater. EPA will also cover wastewater
generated when a shipyard cleans a ship's hull in a dry dock (or similar structure) to remove marine life
(e.g., barnacles) only in preparation for performing MP&M operations.
This Subcategory will cover only process wastewater generated and discharged from
MP&M operations inside and outside ships (including bilge water) that occur in or on dry docks or
similar structures. The Agency is not including MP&M process wastewater that is generated at other
locations at the shipyard ("on-shore" operations) in this Subcategory. EPA expects that wastewater
from these "on-shore" shipbuilding operations (e.g., electroplating, plasma arc cutting) will fall under
either the General Metals or Oily Wastes Subcategories. Also, EPA is not including wastewater
generated onboard ships when they are afloat (i.e., not in dry docks or similar structures). For U.S.
military ships, EPA is in the process of establishing standards under the Uniform National Discharge
Standards (UNDS) pursuant to Section 312(n) of the CWA (See 64 F.R. 25125; May 10, 1999) to
regulate discharges of wastewater generated onboard these ships when they are in U.S. waters and are
afloat (e.g., at a shipyard's dock).
In addition to MP&M wastewater, EPA identified three other types of water streams in
or on dry docks and similar structures: flooding water, dry dock ballast water, and storm water.
Flooding water enters and exits the dry dock or similar structure prior to performing any MP&M
operations. For example, in a graving dock, the gates are opened, allowing flooding water in and ships
to float inside the chamber. Then the flooding water is drained, leaving the ship's exterior exposed so
shipyard employees can repair and maintain the ship's hull. Dry dock ballast water serves a similar
purpose. It is used to lower (or sink) a floating dry dock so that a ship can float over it. Then the dry
dock ballast water is pumped out, raising the dry dock with the ship on top. Flooding water and dry
dock ballast water do not come into contact with MP&M operations. Finally, since these structures
are located outdoors and are exposed to the elements, storm water may fall in or on the dry dock or
similar structures.
EPA is proposing to exclude all three of these water streams from the MP&M rule.
EPA has determined that storm water at these facilities is covered by EPA's recent Storm Water Multi-
Sector General permit, similar general permits issued by authorized states, and individual storm water
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6.0 - Industry Subcategorization
permits. In general, storm water permits at shipyards include best management practices (BMPS) that
are designed to prevent the contamination of storm water. For example, these practices include
sweeping of areas after completion of abrasive blasting or painting.
EPA estimates that there are six indirect dischargers and six direct dischargers in the
Shipbuilding Dry Dock Subcategory. Many shipbuilders operate multiple dry docks (or similar
structures); this is the number of estimated facilities (not dry docks) that discharge MP&M process
wastewater from dry docks or similar structures. Many shipyards perform only dry MP&M unit
operations in their dry docks (and similar structures) or do not discharge wastewater generated in dry
docks (and similar structures) from MP&M unit operations. Many shipyards prefer to handle this
wastewater as hazardous, and contract haul it offsite due to the possible presence of copper (used as
antifoulant) in paint chips from abrasive blasting operations. EPA has determined that shipyards
currently discharging MP&M wastewater from dry docks have oil/water separation technology in
place, such as dissolved air flotation (DAF).
The wastewater discharged from dry docks and similar structures contains very low
levels of metals and toxic organic pollutants. EPA is proposing to exclude wastewater from indirect
discharging dry docks and similar structures at shipbuilding facilities from the MP&M rule. (See
Section 14.0 for a discussion on the rationale for this exclusion). However, EPA is proposing to
regulate conventional pollutants for direct dischargers in this subcategory.
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7.0 - Selection of Pollutant Parameters
7.0 SELECTION OF POLLUTANT PARAMETERS
EPA conducted a study of MP&M wastewater to determine the presence of priority,
conventional, and nonconventional pollutant parameters. The Agency defines priority pollutant
parameters in Section 307(a)(l) of the CWA. In Table 7-1, EPA lists the 126 specific priority
pollutants listed in 40 CFR Part 423, Appendix A. Section 301(b)(2) of the CWA requires EPA to
regulate priority pollutants if EPA determines them to be present at significant concentrations.
Section 304(a)(4) of the CWA defines conventional pollutant parameters to be biochemical oxygen
demand, total suspended solids, oil and grease, pH, and fecal coliform. These pollutant parameters are
subject to regulation as specified in Sections 304(a)(4), 304(b)(l)(a), 301(b)(2)(e), and 306 of the
CWA. Nonconventional pollutant parameters are those that are neither priority nor conventional
pollutant parameters. These include nonconventional metal pollutants, nonconventional organic
pollutants, and other nonconventional pollutant parameters. Sections 301(b)(2)(f) and 301(g) of the
CWA give EPA the authority to regulate nonconventional pollutant parameters, as appropriate, based
on technical and economic considerations.
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7.0 - Selection of Pollutant Parameters
Table 7-1
Priority Pollutant List3
1 Acenaphthene
2 Acrolein
3 Acrylonitrile
4 Benzene
5 Benzidine
6 Carbon Tetrachloride (Tetrachloromethane)
7 Chlorobenzene
8 1,2,4-Trichlorobenzene
9 Hexachlorobenzene
10 1,2-Dichloroethane
11 1,1,1 -Trichloroethane
12 Hexachloroethane
13 1,1-Dichloroethane
14 1,1,2-Trichloroethane
15 1,1,2,2-Tetrachloroethane
16 Chloroethane
17 Removed
18 Bis(2-chloroethyl) Ether
19 2-Chloroethyl Vinyl Ether (mixed)
20 2-Chloronaphthalene
21 2,4,6-Trichlorophenol
22 Parachlorometa Cresol (4-Chloro-3-Methylphenol)
23 Chloroform (Trichlorom ethane)
24 2-Chlorophenol
25 1,2-Dichlorobenzene
26 1,3-Dichlorobenzene
27 1,4-Dichlorobenzene
28 3,3'-Dichlorobenzidine
29 1,1-Dichloroethylene
30 1,2-Trans-Dichloroethylene
31 2,4-Dichlorophenol
32 1,2-Dichloropropane
33 1,3-Dichloropropylene (Trans-1,3-Dichloropropene)
34 2,4-Dimethylphenol
35 2,4-Dinitrotoluene
36 2,6-Dinitrotoluene
37 1,2-Diphenylhydrazine
38 Ethylbenzene
39 Fluoranthene
40 4-Chlorophenyl Phenyl Ether
41 4-Bromophenyl Phenyl Ether
42 Bis(2-Chloroisopropyl) Ether
43 Bis(2-Chloroethoxy) Methane
44 Methylene Chloride (Dichlorom ethane)
45 Methyl Chloride (Chlorom ethane)
46 Methyl Bromide (Bromomethane)
47 Bromoform (Tribromom ethane)
48 Dichlorobromomethane (Bromodichloromethane)
49 Removed
50 Removed
51 Chlorodibromomethane (Dibromochloromethane)
52 Hexachlorobutadiene
53 Hexachlorocyclopentadiene
54 Isophorone
55 Naphthalene
56 Nitrobenzene
57 2-Nitrophenol
58 4-Nitrophenol
59 2,4-Dinitrophenol
60 4,6-Dimtro-o-Cresol (Phenol, 2-methyl-4,6-dimtro)
61 N-Nitrosodimethylamine
62 N-Nitrosodiphenylamine
63 N-Nitrosodi-n-propylamine (Di-n-propylnitrosamine)
64 Pentachlorophenol
65 Phenol
66 Bis(2-ethylhexyl) Phthalate
67 Butyl Benzyl Phthalate
68 Di-n-butyl Phthalate
69 Di-n-octyl Phthalate
70 Diethyl Phthalate
71 Dim ethyl Phthalate
72 Benzo(a)anthracene (1,2-Benzanthracene)
73 Benzo(a)pyrene (3,4-Benzopyrene)
74 Benzo(b) fluoranthene (3,4-Benzo fluoranthene)
75 Benzo(k)fluoranthene (11,12-Benzofluoranthene)
76 Chrysene
77 Acenaphthylene
78 Anthracene
79 Benzo(ghi)perylene (1,12-Benzoperylene)
80 Fluorene
81 Phenanthrene
82 Dibenzo(a,h)anthracene (1,2,5,6-Dibenzanthracene)
83 Indeno(l,2,3-cd)pyrene (2,3-o-Phenylenepyrene)
84 Pyrene
85 Tetrachloroethylene (Tetrachloroethene)
86 Toluene
87 Trichloroethylene (Trichloroethene)
88 Vinyl Chloride (Chloroethylene)
89 Aldrm
90 Dieldrm
91 Chlordane (Technical Mixture & Metabolites)
92 4,4'-DDT (p,p'-DDT)
93 4,4'-DDE (p,p'-DDX)
94 4,4'-DDD (p,p'-TDE)
95 Alpha-endosulfan
96 Beta-endosulfan
97 Endosulfan Sulfate
98 Endrm
99 Endrm Aldehyde
100 Heptachlor
101 Heptachlor Epoxide
102 Alpha-BHC
103 Beta-BHC
104 Gamma-BHC(Lindane)
105 Delta-BHC
106 PCB-1242(Arochlorl242)
107 PCB-1254(Arochlorl254)
108 PCB-1221 (Arochlor 1221)
109 PCB-1232 (Arochlor 1232)
110 PCB-1248 (Arochlor 1248)
111 PCB-1260 (Arochlor 1260)
112 PCB-1016 (Arochlor 1016)
113 Toxaphene
114 Antimony (total)
115 Arsenic (total)
116 Asbestos (fibrous)
117 Beryllium (total)
118 Cadmium (total)
119 Chromium (total)
120 Copper (total)
121 Cyanide (total)
122 Lead (total)
123 Mercury (total)
124 Nickel (total)
125 Selenium (total)
126 Silver (total)
127 Thallium (total)
128 Zinc (total)
129 2,3,7,8-Tetrachloro-dibenzo-p-Dioxm (TCDD)
Source: 40 CFR Part 423, Appendix A.
Priority pollutants are numbered 1 through 129 but include 126 pollutants since EPA removed three pollutants from
the list (Numbers 17, 49, and 50).
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7.0 - Selection of Pollutant Parameters
EPA considered 302 metal and organic pollutant parameters listed in The 1990
Industrial Technology Division List of Analytes (1) for potential regulation under the MP&M proposed
rule. The Agency also considered 22 conventional and other nonconventional pollutant parameters for
potential regulation under the MP&M proposal. These 327 pollutant parameters of which the Agency
measured in the MP&M sampling program are identified in Section 3.0.
The Agency did not consider fecal coliform, a conventional pollutant parameter, for
regulation under the MP&M rule; therefore, it is not included in the 327 pollutant parameters discussed
above. The presence of fecal coliform bacteria, a microorganism that resides in the intestinal tract of
humans and other warm-blooded animals, indicates that wastewater has been contaminated with feces
from humans or other warm-blooded animals. EPA does not expect fecal coliform to be present in
process wastewater from MP&M sites because sanitary wastewater is discharged separately from
process wastewater.
Section 7.1 discusses the criteria used to identify pollutant parameters of concern (i.e.,
considered for regulation) under the MP&M proposed rule. Sections 7.2 and 7.3 present the criteria
used to select pollutant parameters for regulation for direct and indirect dischargers, respectively.
Section 7.4 lists the references used in this chapter.
7.1 Identification of Pollutant Parameters of Concern
EPA analyzed for the 327 pollutant parameters discussed above in over 1,932 samples
of wastewater collected during the MP&M sampling program described in Section 3.0. Of these
samples, EPA collected 727 from unit operation wastewater, 693 from influent-to-treatment
wastewater, and 684 from effluent-from-treatment wastewater. The Agency notes that a number of
these samples fit into more than one category: EPA classified 20 unit operations as influents-to-
treatment and 152 influents-to-treatment for one technology as effluents-from-treatment for a second
technology. EPA reduced the list of 324 pollutants to 132 pollutants (referred to as pollutants of
concern or POCs) for further consideration by retaining only those pollutants that met the following
criteria:
• EPA detected the pollutant parameter in at least three samples collected during
the MP&M sampling program.
• The average concentration of the pollutant parameter in samples of wastewater
from MP&M unit operations and influents-to-treatment was at least five times
the minimum level (ML) or the average concentration of effluent-from-treatment
wastewater samples exceeded five times the minimum level. EPA describes the
ML as "the lowest level at which the entire analytical system must give a
recognizable signal and an acceptable calibration point for the analyte" (2).
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7.0 - Selection of Pollutant Parameters
• EPA analyzed the pollutant parameter in a quantitative manner following the
appropriate quality assurance/quality control (QA/QC) procedures. To meet
this criteria, the Agency excluded wastewater analyses performed solely for
certain semi-quantitative "screening" purposes. EPA performed these semi-
quantitative analyses only in unusual cases (e.g. to qualitatively screen for the
presence of a rare metal such as osmium).
For the first criterion, EPA used data from the unit operation, influent-to-treatment, and
effluent-from-treatment wastewater samples to determine the total number of detected samples for each
pollutant parameter. EPA calculated the average pollutant concentrations from the unit operation and
influent-to-treatment wastewater samples to determine if the data met the second criterion. Separately,
EPA also included effluent-from-treatment wastewater pollutant concentrations in this assessment, and
the following pollutants passed the second criterion: 1,1-dichloroethene, chloroform, diphenyl ether,
isophorone, n-nitrosopiperidine, and trichlorofluoromethane. Because these pollutants have
concentrations exceeding five times the ML in the effluent streams, EPA considered them pollutants of
concern. Of the 324 pollutant parameters initially considered by the Agency for potential regulation
under MP&M, EPA excluded 192 as pollutant parameters of concern for the following reasons:
• EPA did not detect one hundred and thirteen (113) pollutant parameters in
samples collected during the MP&M sampling program. Table 7-2 lists these
pollutant parameters.
• EPA detected fifty (50) in less than three samples collected during the MP&M
sampling program. Table 7-3 lists these pollutant parameters.
• EPA detected thirty (30) pollutant parameters at average concentrations that
were less than five times the ML in unit operations and influent-to-treatment or
did not have a detection limit (acidity, total alkalinity, and pH). Table 7-4 lists
these pollutant parameters.
• EPA did not analyze five of the remaining pollutants (strontium, potassium,
sulfur, silicon, and phosphorus) in a quantitative manner. Rather, EPA
performed analyses for these pollutants using semi-quantitative methods for
"screening" purposes to determine if these analytes were present. Therefore,
the Agency did not subject these analytes to the QA/QC procedures required
by analytical method 1620. Based on the screening results, the Agency
performed a full quantitative analysis for gold, palladium, platinum, and
rhodium.
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7.0 - Selection of Pollutant Parameters
Table 7-2
Pollutant Parameters Not Detected in Any Samples Collected During the
MP&M Sampling Program
Priority Pollutant Parameters
1 ,2-Dichloropropane
1 , 3 -Dichlorobenzene
2-Chloroethylvinyl Ether
3 , 3 '-Dichlorobenzidine
4-Bromophenyl Phenyl Ether
4-Chlorophenylphenyl Ether
Acenaphthylene
Benzidine
Benzo(A)Anthracene
Benzo(A)Pyrene
Benzo(B)Fluoranthene
Benzo(Ghi)Perylene
Benzo(K)Fluoranthene
Bis(2-Chloroisopropyl) Ether
Chrysene
Dibenzo(A,H) Anthracene
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Indeno( 1,2,3 -Cd)Pyrene
Pentachlorophenol
Trans- 1 ,2-Dichloroethene
Trans- 1 ,3 -Dichloropropene
Nonconventional Organic Pollutant Parameters
1 ,2,3 -Trichlorobenzene
1 ,2,3 -Trichloropropane
1 ,2,3-Trimethoxybenzene
1 ,2,4,5-Tetrachlorobenzene
1 ,2-Dibromo-3-Chloropropane
1 ,2-Dibromoethane
1,3 -Butadiene, 2-Chloro
1 ,3-Dichloro-2-Propanol
1 , 3 -Dichloropropane
1 ,5-Naphthalenediamine
1 -Chloro-3 -Nitrobenzene
1 -Pheny Inaphthalene
2,3,4,6-Tetrachlorophenol
2, 3 ,6-Trichlorophenol
2, 3 -B enzofluorene
2, 3 -Dichloroaniline
2, 3 -Dichloronitrobenzene
2,4,5-Trichlorophenol
2,6-Dichloro-4-Nitroaniline
2,6-Dichlorophenol
2-Methylbenzothioazole
2-Nitroaniline
2-Pheny Inaphthalene
Aniline, 2,4,5-Trimethyl-
Aramite
Benzanthrone
Benzenethiol
Biphenyl, 4-Nitro
Chloroacetonitrile
Crotonaldehyde
Crotoxyphos
Diethyl Ether
Dimethyl Sulfone
Dipheny Idi sulf ide
Ethyl Cyanide
Ethyl Methacrylate
Ethyl Methanesulfonate
Hexachloropropene
lodomethane
Isosafrole
Longifolene
Malachite Green
Mestranol
Methapyrilene
Methyl Methanesulfonate
n-Nitrosodiethylamine
7-5
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7.0 - Selection of Pollutant Parameters
Table 7-2 (Continued)
Nonconventional Organic Pollutant Parameters (continued)
2-Propen-l-Ol
2-Propenenitrile, 2-Methyl-
3,3'-Dimethoxybenzidine
3,5-Dibromo 4-Hydroxybenzonitrile
3-Chloropropene
3 -Methy Icholanthrene
3-Nitroaniline
4,4'-Methylenebis(2-Chloroaniline)
4,5-Methylene Phenanthrene
4-Chloro-2-Nitroaniline
5-Nitro-O-Toluidine
7, 1 2-Dimethylbenz(A)Anthracene
o-Toluidine, 5-Chloro-
p-Dimethylaminoazobenzene
Pentachlorobenzene
Pentachloroethane
Perylene
Phenacetin
Pronamide
Squalene
Thioacetamide
Trans- 1 ,4-Dichloro-2-Butene
Triphenylene
Vinyl Acetate
Nonconventional Metal Pollutant Parameters
Cerium
Erbium
Europium
Gadolinium
Gallium
Germanium
Holmium
Indium
Iodine
Lanthanum
Praseodymium
Rhenium
Samarium
Scandium
Tellurium
Terbium
Thorium
Thulium
Uranium
Source: MP&M sampling data.
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7.0 - Selection of Pollutant Parameters
Table 7-3
Pollutant Parameters Detected in Less Than Three Samples Collected
During the MP&M Sampling Program
Priority Pollutant Parameters
1 , 1 ,2,2-Tetrachloroethane
1 , 1 ,2-Trichloroethane
1 ,2,4-Trichlorobenzene
1 ,2-Dichlorobenzene
1 ,2-Dichloroethane
1 ,2-Diphenylhydrazine
1 ,4-Dichlorobenzene
2,4-Dichlorophenol
2,4-Dinitrotoluene
2-Chloronaphthalene
2-Chlorophenol
Acrylonitrile
Bis(2-Chloroethoxy)Methane
Bis(2-Chloroethyl) Ether
Bromomethane
Nitrobenzene
n-Nitrosodi-n-Propylamine
Vinyl Chloride
Nonconventional Organic Pollutant Parameters
1,1,1 ,2-Tetrachloroethane
1,2:3 ,4-Diepoxy butane
1,3,5-Trithiane
1 ,4-Dinitrobenzene
1 ,4-Naphthoquinone
1 -Naphthylamine
2,6-Di-Tert-Butyl-P-Benzoquinone
2-Picoline
4-Aminobiphenyl
Beta-Naphthylamine
Carbazole
Cis- 1 ,3 -Dichloropropene
Dibromomethane
Ethylenethiourea
n-Nitrosodi-n-Butylamine
n-Nitrosomethylphenylamine
o-Anisidine
p-Chloroaniline
Pentamethylbenzene
Phenothiazine
p-Nitroaniline
Resorcinol
Safrole
Thianaphthene
Thioxanthe-9-One
Toluene, 2,4-Diamino-
Nonconventional Metal Pollutant Parameters
Dysprosium
Hafnium
Neodymium
Rhodium
Ruthenium
Zirconium
Source: MP&M sampling data.
7-7
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7.0 - Selection of Pollutant Parameters
Table 7-4
Pollutant Parameters Detected at Average Concentrations of Less Than
Five Times the Minimum Level During the MP&M Sampling Program
Priority Pollutant Parameters
2,4,6-Trichlorophenol
4,6-Dinitro-o-Cresol
Benzene
Bromodichloromethane
Carbon Tetrachloride (Tetrachloromethane)
Chloroform
Chloromethane
Dibromochloromethane
Diethyl Phthalate
Tribromomethane
Nonconventional Organic Pollutant Parameters
2- (Methy lthio)Benzothi azole
Diphenyl Ether
n-Nitrosomethylethylamine
n-Nitrosomorpholine
n-Nitro sopiperidine
o-Toluidine
Trichlorofluoromethane
Nonconventional Metal Pollutant Parameters
Bismuth
Iridium
Lithium
Lutetium
Niobium
Osmium
Palladium
Tantalum
Tungsten
Ytterbium
Source: MP&M sampling data.
After excluding these pollutants, EPA defines the 132 remaining pollutants as pollutant
parameters of concern (POCs). These include 48 priority pollutant parameters (34 priority organic
pollutants, 13 priority metal pollutants, and cyanide), 3 conventional pollutant parameters, and 81
nonconventional pollutant parameters (50 organic pollutants, 15 metal pollutants, and 16 other
nonconventional pollutants). These pollutant parameters, along with the number of times EPA analyzed
and detected each pollutant parameter in the influent or in unit operations and the corresponding
average concentration (excluding nondetected pollutants), are shown in Table 7-5.
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7.0 - Selection of Pollutant Parameters
Table 7-5
Pollutant Parameters Selected for Further
Consideration Under the MP&M Proposed Rule
Pollutant Parameter
No. of Times
Analyzed for All
Samples
No. of Times
Detected for All
Samples
Average Concentration
in Samples from Unit
Operations and
Treatment Influents
(mg/L)
Priority Organic Pollutants
1,1,1 -Trichloroethane
1 , 1 -Dichloroethane
1 , 1 -Dichloroethylene
2,4-Dimethylphenol
2,4-Dinitrophenol
2,6-Dinitrotoluene
2-Nitrophenol
4-Chlorom-cresol
4-Nitrophenol
Acenaphthene
Acrolein
Anthracene
Bis(2-Ethylhexyl) Phthalate
Benzyl Butyl Phthalate
Chlorobenzene
Chloroethane
Chloroform
Di-N-Butyl Phthalate
Di-N-Octyl Phthalate
Dimethyl Phthalate
Ethylbenzene
Fluoranthene
Fluorene
Isophorone
Methylene Chloride
n-Nitrosodimethylamine
N-Nitrosodiphenylamine
Naphthalene
Phenanthrene
Phenol
Pyrene
1043
1043
1043
994
946
1029
1021
1003
969
1029
1003
1029
1028
1026
1043
1043
1043
1026
1028
994
1043
1028
1029
996
1043
996
1029
1029
1029
1021
1028
28
7
3
31
4
3
9
95
5
6
5
4
211
16
7
4
331
41
18
o
J
61
4
18
3
52
3
15
71
45
244
5
0.327
0.091
0.418
0.078
83.7
2.73
0.394
260
2.99
0.332
0.307
0.117
4.15
1.08
0.282
4.22
0.049
0.352
1.58
0.739
0.165
0.132
0.956
0*
0.403
3.68
1.14
0.638
0.500
10.1
0.219
7-9
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7.0 - Selection of Pollutant Parameters
Table 7-5 (Continued)
Pollutant Parameter
Tetrachloroethene
No. of Times
Analyzed for All
Samples
1043
No. of Times
Detected for All
Samples
23
Average Concentration
in Samples from Unit
Operations and
Treatment Influents
(mg/L)
0.210
Priority Organic Pollutants (continued)
Toluene
Trichloroethylene
1043
1042
83
40
0.230
0.092
Priority Metal Pollutants
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Cyanide
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
1956
1972
1972
1972
1972
1972
406
1972
1970
1972
1956
1972
1956
1971
606
627
301
873
1480
1752
327
911
321
1518
317
698
206
1691
6.12
0.178
0.147
244
1,029
495
2,072
30.0
0.0014
356
0.137
0.531
0.065
188
Conventional Pollutants
BOD 5-Day (Carbonaceous)
Oil And Grease (As HEM)
Total Suspended Solids
1005
1028
1959
757
554
1563
2,015
2,308
1,007
Nonconventional Organic Pollutants
1,4-Dioxane
1 -Bromo-2-Chlorobenzene
1 -Bromo-3 -Chlorobenzene
1 -Methy Ifluorene
1 -Methy Iphenanthrene
2-Butanone
2-Hexanone
2-Isopropylnaphthalene
2-Methylnaphthalene
2-Propanone
3,6-Dimethylphenanthrene
4-Methyl-2-Pentanone
Acetophenone
1003
989
989
989
989
1003
1003
989
989
1003
989
1003
989
33
8
6
24
29
160
7
6
61
593
13
91
10
0.854
0.233
0.135
0.347
0.581
1.59
1.26
3.21
0.775
3.14
1.24
5.19
0.159
7-10
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7.0 - Selection of Pollutant Parameters
Table 7-5 (Continued)
Pollutant Parameter
Alpha-Terpineol
No. of Times
Analyzed for All
Samples
978
No. of Times
Detected for All
Samples
133
Average Concentration
in Samples from Unit
Operations and
Treatment Influents
(mg/L)
13.6
Nonconventional Organic Pollutants (continued)
Aniline
Benzoic Acid
Benzyl Alcohol
Biphenyl
Carbon Bisulfide
Dibenzofuran
Dibenzothiophene
Diphenyl Ether
Diphenylamine
Hexanoic Acid
Isobutyl Alcohol
m+p Xylene
m-Xylene
Methyl Methacrylate
n,n-Dimethylform amide
n-Decane
n-Docosane
n-Dodecane
n-Eicosane
n-Hexacosane
n-Hexadecane
n-Nitrosopiperidine
n-Octacosane
n-Octadecane
n-Tetracosane
n-Tetradecane
n-Triacontane
o+p Xylene
o-Cresol
o-Xylene
p-Cresol
p-Cymene
Pyridine
Styrene
Trichlorofluoromethane
989
989
989
989
1003
989
988
989
989
989
1003
595
408
1003
989
989
989
989
988
989
989
989
989
989
988
989
988
408
989
595
989
989
989
989
1043
19
202
61
23
63
4
6
5
14
237
19
31
21
6
63
67
108
125
156
95
168
4
40
174
90
158
55
30
16
40
82
21
37
9
12
0.684
277
1.23
0.174
0.408
0.055
0.240
0.047
0.704
15.2
0.167
0.159
0.498
0.396
0.193
2.10
3.47
13.8
3.30
5.84
6.27
0.020
7.45
5.74
4.13
12.7
2.69
0.256
0.067
0.058
0.293
0.988
0.920
0.261
0.049
7-11
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7.0 - Selection of Pollutant Parameters
Table 7-5 (Continued)
Pollutant Parameter
Tripropyleneglycol Methyl Ether
No. of Times
Analyzed for All
Samples
989
No. of Times
Detected for All
Samples
141
Average Concentration
in Samples from Unit
Operations and
Treatment Influents
(mg/L)
190
Nonconventional Metal Pollutants
Aluminum
Barium
Boron
Calcium
Cobalt
Gold
Iron
Magnesium
Manganese
Molybdenum
Sodium
Tin
Titanium
Vanadium
Yttrium
1972
1972
1913
1972
1972
161
1972
1972
1972
1972
1972
1912
1913
1972
1913
1520
1651
1645
1929
640
104
1743
1803
1620
1091
1953
850
949
504
306
166
1.75
85.0
68.4
12.8
16.2
777
53.8
43.4
2.97
3,384
153
32.6
5.31
0.061
Other Nonconventional Pollutants
Amenable Cyanide
Ammonia As Nitrogen
Chemical Oxygen Demand (COD)
Chloride
Fluoride
Hexavalent Chromium
Sulfate
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbons (As SGT-HEM)
Total Phosphorus
Total Recoverable Phenolics
Total Sulfide
Weak -Acid Dissociable Cyanide
Ziram
160
689
1461
677
688
1074
1171
1953
661
997
1016
500
1357
215
72
31
128
569
1343
631
618
268
1086
1948
572
838
350
452
871
80
62
22
44.3
385
11,289
5,526
301
1.78
7,046
21,883
606
3,385
841
170
11.7
6.50
19.4
1.41
Source: MP&M sampling data.
7-12
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7.0 - Selection of Pollutant Parameters
7.2 Pollutants Proposed to be Regulated for Direct Dischargers
EPA developed the list of pollutants to be regulated for each of the MP&M
subcategories from the pollutants of concern list discussed above. As a first step in the selection of
regulated pollutants, the Agency grouped the MP&M subcategories (discussed in Section 6) according
to whether the facilities in the subcategory generated wastewater with high metals content (metal-
bearing) or wastewater with low concentration of metals and high oil and grease content (oil-bearing).
EPA determined that the following subcategories generate metal-bearing wastewater: General Metals,
Metal Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Board, and Steel Forming and
Finishing. For the remainder of the subcategories (Oily Wastes, Railroad Line Maintenance, and
Shipbuilding Dry Docks), the Agency determined that they generate oil-bearing wastewater. For both
of these groups, the Agency analyzed the concentrations and prevalence of the pollutants of concern
from unit operations, unit operation rinses, and influent to treatment systems in order to determine which
POCs EPA could eliminate from its list of pollutants considered for regulation. The tables in Section 5
summarize the data that EPA considered in determining the pollutants selected for regulation.
EPA considered the following factors in determining which POCs should be eliminated
from the potential list of regulated pollutants:
• The pollutant is controlled through the regulation of other pollutants.
• The pollutant is present in only trace amounts in the subcategory and/or is not
likely to cause toxic effects.
• The pollutant may serve as a treatment chemical.
• The pollutant is not controlled by the selected BPT/BAT technology.
7.2.1 Regulated Pollutant Analysis for Direct Dischargers in the Metal-Bearing
Subcategories
As mentioned in Section 7.2, EPA determined that the following subcategories generate
metal-bearing wastewater: General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing,
Printed Wiring Board, and Steel Forming and Finishing. This section describes EPA's proposed
regulated pollutant selection criteria for direct dischargers in the metal-bearing subcategories.
EPA did not select the 42 pollutants of concern present in Table 7-6 because they are
controlled through the regulation of other pollutants in the metal-bearing subcategories.
7-13
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7.0 - Selection of Pollutant Parameters
Table 7-6
Pollutants Not Selected for Proposed Regulation for the Metal-Bearing
Subcategories Because They Are Controlled Through the Regulation of
Other Pollutants
Conventional Pollutant
BOD5
Other Nonconventional Pollutant
COD
Hexavalent Chromium
Total Petroleum Hydrocarbons (as SGT-HEM)
Total Recoverable Phenolics
Weak -Acid Dissociable Cyanide
Nonconventional Organic Pollutants
1 ,4-Dioxane
1 -Bromo-2-Chlorobenzene
1 -Bromo-3-Chlorobenzene
2-Butanone
2-Hexanone
2-Propanone
4-Methyl-2-Pentanone
Acetophenone
Alpha- Terpineol
Benzyl Alcohol
Diphenyl Ether
Diphenylamine
Hexanoic Acid
Isobutyl Alcohol
m+p Xylene
m-Xylene
Methyl Methacrylate
n,n-Dimethylformamide
n-Decane
n-Docosane
n-Dodecane
n-Eicosane
n-Hexacosane
n-Nitrosopiperidine
n-Octacosane
n-Octadecane
n-Tetracosane
n-Triacontane
o+p Xylene
o-Cresol
o-Xylene
p-Cresol
Pyridine
Styrene
Trichlorofluoromethane
Tripropylenenglycol Methyl Ether
BOD5 and COD are methods for measuring the oxygen demand of wastewater. EPA
is proposing a limit for Total Organic Carbon (TOC), an alternate method that measures all oxidizable
organic material in a waste stream, including some organic chemicals not oxidized (and, therefore not
detected) in the BOD5 and COD tests. EPA chose TOC as an indicator parameter because of its
ability to measure all types of organic pollutants and because it found TOC to be the best general
indicator parameter for measuring the sum of organic compounds in an MP&M waste stream. EPA is
not proposing a limit for hexavalent chromium because it has selected total chromium for regulation.
Weak-acid dissociable cyanide will be controlled through the regulation of total cyanide (or amenable
7-14
-------
7.0 - Selection of Pollutant Parameters
cyanide). EPA did not propose a limit for Total Petroleum Hydrocarbons (TPH) (as SGT-HEM)
because it believes that the regulation of oil and grease (O&G) and EPA's proposed organics control
options will control the discharge of TPH (as SGT-HEM). The parameter Total Recoverable
Phenolics will be controlled through the regulation of the Total Organics Parameter (TOP) which
includes compounds such as phenol. EPA also believes that the list of 36 nonconventional organic
compounds listed in the table above will be controlled through the regulation of TOP. The organic
parameters that comprise the TOP are explained in more detail later in this section.
EPA determined that it was not necessary to propose limits for the 12 metals listed in
Table 7-7 because it detected these metals at low levels in its sampling of MP&M wastewater. As
shown in Table 5-14, the median concentration at the influent to treatment for all of these metals was
less than 0.1 mg/L. EPA also decided not to propose a limit for fluoride because the Agency did not
detect fluoride at concentrations that would cause toxic effects. As shown in Table 5-14, the median
concentration of fluoride at the influent to treatment was 1.55 mg/L. This value is below EPA's primary
drinking water standard for fluoride (the maximum contaminant level (MCL)) which is 4 mg/L.
Table 7-7
Pollutants Not Selected for Proposed Regulation for the Metal-Bearing
Subcategories Because They Are Present in Only Trace Amounts and/or
Are Not Likely to Cause Toxic Effects
Priority Metals
Antimony
Arsenic
Beryllium
Mercury
Selenium
Thallium
Nonconventional Metals
Barium
Cobalt
Gold
Titanium
Vanadium
Yttrium
Other Nonconventional Pollutant
Fluoride
EPA did not select the 8 pollutants of concern presented in Table 7-8 for proposed
regulation in the metal-bearing subcategories because they may be used as treatment chemicals in the
MP&M industry.
7-15
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7.0 - Selection of Pollutant Parameters
Table 7-8
Pollutants Not Selected for Proposed Regulation for the Metal-Bearing
Subcategories Because They May Serve as Treatment Chemicals in the
MP&M Industry
Nonconventional Metals
Aluminum
Calcium
Iron
Magnesium
Sodium
Other Nonconventional Pollutants
Sulfate
Chloride
Ziram
EPA eliminated the nonconventional metals listed in Table 7-8 plus sulfate and chloride
from consideration because regulation of these pollutants could interfere with their beneficial use as
wastewater treatment additives. In the case of ziram, EPA detected this pollutant at MP&M facilities
that use sodium dimethyldithiocarbamate (DTC) as a reducing and precipitating agent in the treatment
of complexed or chelated metals. For the MP&M proposal, EPA based the estimated costs and
pollutant removals associated with the treatment of chelated or complexed metals on the use of DTC.
When DTC is used appropriately, it may effectively enhance the removal of some difficult to treat
pollutants without impacting the environment or POTW operations. However, DTC is toxic to aquatic
life and to activated sludge and thus can upset POTW operations. DTC can combine to form, or break
down to, a number of other toxic chemicals, including thiram and ziram (both EPA registered
fungicides) and other thiurams, other dithiocarbamates, carbon disulfide, and dimethylamine. Ziram is
known to be toxic to aquatic life at the following levels: LC 50 less than 10 ug/L (parts per billion) for
several varieties of bluegill and trout; LC 50 between 10 and 100 ug/L in other studies (see AQUTRE
database at http://www.epa.gov/medecotx/quicksearch.htm). EPA solicits comment in the proposal on
the use of DTC for the treatment of chelated wastewater and its potential harmful effects on the
environment and on POTW operations. As explained in the proposed rule, the Agency is particularly
interested in receiving data and information on alternative treatments for wastewater containing chelated
or complexed metals.
EPA did not select the 5 pollutants of concern presented in Table 7-9 for proposed
regulation in the metal-bearing subcategories because they are not controlled by the selected BPT/B AT
technology. EPA's analytical data showed that the proposed BPT/B AT treatment option did not
effectively remove the low levels of ammonia as nitrogen or the low levels of Total Kjeldahl Nitrogen
present in MP&M wastewater. As shown in Table 5-14, the median ammonia concentration at the
influent to treatment was only 2.56 mg/L and treatment systems sampled by EPA achieved on average
less than 20 percent removal. Similarly, the proposed BPT/B AT treatment systems sampled by EPA
7-16
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7.0 - Selection of Pollutant Parameters
did not demonstrate effective removal of boron, total phosphorous, or Total Dissolved Solids and only
demonstrated incidental removal of boron.
Table 7-9
Pollutants Not Selected for Proposed Regulation for the Metal-Bearing
Subcategories Because They Are Not Controlled by the Selected BPT/BAT
Technology
Other Nonconventional Pollutants
Ammonia as
Nitrogen
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Phosphorous
Nonconventional Metal Pollutant
Boron
EPA considered proposing limits for all of the priority and nonconventional organic
pollutants listed in Table 7-10; however, due to the variety of organic pollutants used across MP&M
facilities, EPA determined that it would be burdensome to facilities and permit writers/control authorities
have to determine which limits to apply to a facility. Instead, EPA is proposing an approach similar to
the one used in the Metal Finishing Effluent Guidelines (40 CFR Part 433). EPA developed a list of
organic pollutants, called the Total Organics Parameter (TOP), using the list of organic priority
pollutants and other nonconventional organic pollutants that met EPA's pollutant of concern criteria for
this rule. Of the nonconventional organic chemicals on the MP&M pollutant of concern list, EPA
included only those that were removed in appreciable quantities by the selected technology option
(based on toxic weighted pound-equivalents) in two or more subcategories. The TOP list is comprised
of all of the priority and nonconventional organic pollutants listed in Table 7-10.
7-17
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7.0 - Selection of Pollutant Parameters
Table 7-10
64 Remaining Pollutants Considered for Proposed Regulation for the Metal-
Bearing Subcategories
Priority Metals
Cadmium
Chromium
Copper
Cyanide
Lead
Nickel
Silver
Zinc
Nonconventional Metals
Manganese
Molybdenum
Tin
Conventional Pollutants
Oil and Grease (as HEM)
Total Suspended Solids
Other Nonconventional Pollutants
Amenable Cyanide
Total Organic Carbon
Total Sulfide
Priority Organic Pollutants
1,1,1 -Trichloroethane
1 , 1 -Dichloroethane
1 , 1 -Dichloroethylene
2,4-Dimethylphenol
2,4-Dinitrophenol
2,6-Dinitrotoluene
2-Nitrophenol
4-Chloro-m-cresol
4-Nitrophenol
Acenaphthene
Acrolein
Anthracene
Benzyl Butyl Phthalate
Bis(2-Ethylhexyl) Phthalate
Chlorobenzene
Chloroethane
Chloroform
1 -Methylfluorene
1 -Methylphenanthrene
2-Isopropylnaphthalene
2-Methylnaphthalene
Di-n-Butyl Phthalate
Di-n-Octyl Phthalate
Dimethyl Phthalate
Ethylbenzene
Fluoranthene
Fluorene
Isophorone
Methylene Chloride
n-Nitrosodimethylamine
n-Nitrosodiphenylamine
Naphthalene
Phenanthrene
Phenol
Pyrene
Tetrachloroethene
Toluene
Trichloroethylene
Biphenyl
Carbon Bisulfide
Dibenzofuran
Dibenzothiophene
7-18
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7.0 - Selection of Pollutant Parameters
Table 7-10 (Continued)
Nonconventional Organic Pollutants
3 ,6-Dimethy Iphenanthrene
Aniline
Benzoic Acid
n-Hexadecane
n-Tetradecane
p-Cymene
EPA has derived the numerical limit for TOP based on the contribution of each of the
organic pollutants listed in Table 7-10 using the data collected during sampling and determined the
limitation using the same statistical methodology used for other limits developed for this proposal (see
Table 10-7 for the list of TOP pollutants). In any case where the data for these pollutants indicated a
level below the minimum level (ML) (i.e., below quantitation), EPA used the ML for the specific
pollutant in the summation of the TOP limit. Facilities will only have to monitor for those TOP
chemicals that are reasonably present (see Section 15.2.6 for a discussion on monitoring waivers).
Note that the TOP limit shall not be adjusted for those pollutants that are not reasonably present. In the
proposal, EPA solicits comment on this methodology.
As discussed above, EPA is also proposing to allow the use of an indicator parameter
to measure the presence of organic pollutants in MP&M process wastewater. Facilities can monitor
for the organic pollutants specified in the TOP list to demonstrate compliance with the TOP limit or they
can monitor for Total Organic Carbon (TOC) and meet the TOC limit.
Finally, EPA is proposing a third alternative to reduce monitoring burden - the use of an
organic pollutant management plan. The organic pollutant management plan would need to specify the
following, to the satisfaction of the permitting authority or control authority:
• The toxic and non-conventional organic constituents used at the facility;
• The disposal method used;
• The procedures in place for ensuring that organic pollutants do not routinely
spill or leak into the wastewater or that minimize the amount of organic
pollutants used in the process;
• The procedures in place to manage the oxidation reduction potential (ORP)
during cyanide destruction to control the formation of chlorinated organic
byproducts; and
• The procedures to prevent the over dosage of dithiocarbamates when treating
chelated wastewater.
7-19
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7.0 - Selection of Pollutant Parameters
Facilities choosing to develop an organic pollutant management plan would need to
certify that the procedures described in the plan are being implemented at the facility. Section 15.2.6
explains the organic management plan in greater detail.
In order to determine the pollutants proposed for regulation for each of the metal-
bearing subcategories, EPA considered each of the remaining pollutants in Table 7-10 on a
subcategory-by-subcategory basis. That is, after eliminating the pollutants listed in Tables 7-6 through
7-9 by analyzing all of the data for the metal-bearing subcategories combined, EPA then considered
only data from each individual subcategory in order to determine the proposed regulated pollutants for
each subcategory.
7.2.1.1 General Metals Subcategory
For the direct dischargers in the General Metals subcategory, EPA proposed
regulations for all of the pollutants listed in Table 7-10. For the organic parameters listed in Table 7-9,
facilities in this subcategory may choose from the following three options in order to comply with the
regulation: comply with the limit for TOC; comply with the limit for TOP; or implement an organic
pollutant management plan. Section 14 lists the effluent limitations for direct dischargers in the General
Metals subcategory.
7.2.1.2 Metal Finishing Job Shops Subcategory
For the direct dischargers in the Metal Finishing Job Shops subcategory, EPA
proposed regulations for all of the pollutants listed in Table 7-10. For the organic parameters listed in
Table 7-10, facilities in this subcategory may choose from the following three options in order to
comply with the regulation: comply with the limit for TOC; comply with the limit for TOP; or implement
an organic pollutant management plan. Section 14 lists the effluent limitations for direct dischargers in
the Metal Finishing Job Shops subcategory.
7.2.1.3 Non-Chromium Anodizing Subcategory
For the direct dischargers in the Non-Chromium Anodizing subcategory, EPA
proposed regulations for TSS, O&G, aluminum, manganese, nickel, and zinc. Although EPA had
eliminated aluminum from consideration for regulation for the metal-bearing subcategories because of its
use as a treatment chemical, EPA decided to propose limits for aluminum for direct dischargers in this
subcategory because of the large amount of aluminum discharged by non-chromium anodizing facilities.
(See Section 6.6.3 for a description of the Non-Chromium Anodizing subcategory.) EPA also
determined that unit operations performed at non-chromium anodizing facilities may generate
wastewater containing significant quantities of manganese, nickel, and zinc and is proposing effluent
limitations for these three metals. The Agency did not identify a large number of organic pollutants in
wastewater from non-chromium anodizing operations and therefore did not propose a TOC or TOP
limit for these dischargers. It did, however, propose a limit for O&G to control the discharge of this
7-20
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7.0 - Selection of Pollutant Parameters
pollutant into surface water. Section 14 lists the effluent limitations for direct dischargers in the Non-
Chromium Anodizing sub category.
7.2.1.4 Printed Wiring Board Subcategory
For the direct dischargers in the Printed Wiring Board subcategory, EPA is proposing
regulations for all of the pollutants listed in Table 7-10 except cadmium, molybdenum and silver. These
three metals were not found at significant concentrations at facilities in the this subcategory. For the
organic parameters listed in Table 7-10, facilities in the Printed Wiring Board subcategory may choose
from the following three options in order to comply with the regulation: comply with the limit for TOC;
comply with the limit for TOP; or implement an organic pollutant management plan. Section 14 lists the
effluent limitations for direct dischargers in the Printed Wiring Board subcategory.
7.2.1.5 Steel Forming and Finishing Subcategory
For the direct dischargers in the Steel Forming and Finishing subcategory, EPA
proposed regulations for all of the pollutants listed in Table 7-10. For the organic parameters listed in
Table 7-10, facilities in this subcategory may choose from the following three options in order to
comply with the regulation: comply with the limit for TOC; comply with the limit for TOP; or implement
an organic pollutant management plan. Section 14 lists the effluent limitations for direct dischargers in
the Steel Forming and Finishing subcategory.
7.2.2 Regulated Pollutant Analysis for Direct Dischargers in the Oil-Bearing
Subcategories
As mentioned in Section 7.2, EPA determined that the following subcategories generate
oil-bearing wastewater: Oily Wastes, Railroad Line Maintenance, and Shipbuilding Dry Docks. This
section describes EPA's proposed regulated pollutant selection criteria for direct dischargers in the oil-
bearing subcategories.
EPA did not select the 39 pollutants of concern presented in Table 7-11 that are
controlled through the regulation of other pollutants in the oil-bearing subcategories.
7-21
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7.0 - Selection of Pollutant Parameters
Table 7-11
Pollutants Not Selected for Proposed Regulation for the Oil-Bearing
Subcategories Because They Are Controlled Through the Regulation of
Other Pollutants
Other Nonconventional Pollutants
COD
Total Petroleum Hydrocarbons (as SGT-HEM)
Total Recoverable Phenolics
Nonconventional Organic Pollutants
1 ,4-Dioxane
1 -Bromo-2-Chlorobenzene
1 -Bromo-3-Chlorobenzene
2-Butanone
2-Hexanone
2-Propanone
4-Methyl-2-Pentanone
Acetophenone
Alpha- Terpineol
Benzyl Alcohol
Diphenyl Ether
Diphenylamine
Hexanoic Acid
Isobutyl Alcohol
m+p Xylene
m-Xylene
Methyl Methacrylate
n,n-Dimethylformamide
n-Decane
n-Docosane
n-Dodecane
n-Eicosane
n-Hexacosane
n-Nitro sopiperidine
n-Octacosane
n-Octadecane
n-Tetracosane
n-Triacontane
o+p Xylene
o-Cresol
o-Xylene
p-Cresol
Pyridine
Styrene
Trichlorofluoromethane
Tripropylenenglycol Methyl Ether
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7.0 - Selection of Pollutant Parameters
COD is a method for measuring the oxygen demand of wastewater. For the oil-
bearing subcategories, EPA did not select COD for proposed regulation, but instead is proposing
alternative parameters for measuring the oxygen demand of a wastewater. For the Oily Wastes
subcategory, EPA is proposing a limit for Total Organic Carbon (TOC), an alternate method that
measures all oxidizable organic material in a waste stream, including some organic chemicals not
oxidized (and, therefore not detected) in the COD test. EPA chose TOC as an indicator parameter
because of its ability to measure all types of organic pollutants and is found to be the best general
indicator parameter for measuring the sum of organic compounds in an MP&M waste stream. For the
Railroad Line Maintenance subcategory, EPA is proposing limitations for BOD5 rather than COD, and
for the Shipbuilding Dry Dock subcategory it has determined that the regulation of only O&G was
necessary to control the removal of organic constituents.
EPA did not propose a limit for Total Petroleum Hydrocarbons (TPH) (as SGT-HEM)
because it believes that the regulation of O&G (as HEM) and EPA's proposed organics control options
will control the discharge of TPH (as SGT-HEM). The parameter Total Recoverable Phenolics will be
controlled through the regulation of the Total Organics Parameter (TOP) which includes compounds
such as phenol. EPA also believes that the list of 36 nonconventional organic compounds listed in
Table 7-11 will be controlled through the regulation of TOP. The organic parameters that comprise the
TOP are explained in more detail later in this section.
Table 7-12 presents 28 pollutants of concerns that are present in only trace amounts in
the oil-bearing subcategories and/or are not likely to cause toxic effects. EPA determined that it was
not necessary to propose limits for these metals listed because it detected these metals at low levels in
its sampling of oil-bearing wastewater. As shown in Table 5-10, the average concentration at the
influent to treatment for each of these metals is less than 0.1 mg/L.
Table 7-12
Pollutants Not Selected for Proposed Regulation for the Oil-Bearing
Subcategories Because They Are Present in Only Trace Amounts and/or
Are Not Likely to Cause Toxic Effects
Priority Metals
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Cyanide
Mercury
Nickel
Selenium
Silver
Thallium
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7.0 - Selection of Pollutant Parameters
Table 7-12 (Continued)
Nonconventional Metals
Cobalt
Gold
Molybdenum
Tin
Titanium
Vanadium
Yttrium
Nonconventional Organic
Carbon Bisulfide
Other Nonconventional Pollutants
Amenable Cyanide
Ammonia as Nitrogen
Fluoride
Hexavalent Chromium
Total Dissolved Solids
Total Kjeldahl Nitrogen
Weak -Acid Dissociable Cyanide
Ziram
EPA did not select the 7 pollutants of concern presented in Table 7-13 for proposed
regulation in the oil-bearing subcategories because they may be used as treatment chemicals in the
MP&M industry.
Table 7-13
Pollutants Not Selected for Proposed Regulation for the Oil-Bearing
Subcategories Because They May Serve as Treatment Chemicals in the
MP&M Industry
Nonconventional Metals
Aluminum
Calcium
Iron
Magnesium
Sodium
Other Nonconventional Pollutants
Chloride
Sulfate
EPA did not select the 6 pollutants of concern presented in Table 7-14 for proposed
regulation in the oil-bearing subcategories because they are not controlled by the selected BPT/B AT
technology.
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7.0 - Selection of Pollutant Parameters
Table 7-14
Pollutants Not Selected for Proposed Regulation for the Oil-Bearing
Subcategories Because They Are Not Controlled by the
Selected BPT/BAT Technology
Priority Metal Pollutants
Lead
Zinc
Nonconventional Metal Pollutants
Barium
Boron
Manganese
Other Nonconventional Pollutant
Total Phosphorous
In order to determine the pollutants proposed for regulation for each of the oil-bearing
subcategories, EPA considered each of the remaining pollutants in Table 7-15 on a subcategory-by-
subcategory basis. That is, after eliminating the pollutants listed in Tables 7-11 through 7-14 by
analyzing all of the data for the oil-bearing subcategories combined, EPA then considered only data
from each individual subcategory in order to determine the proposed regulated pollutants for each
sub category.
Table 7-15
49 Remaining Pollutants Considered for Proposed Regulation
for the Oil-Bearing Subcategories
Conventional Pollutants
BOD5
Oil and Grease
Total Suspended Solids
Other Nonconventional Pollutants
Total Organic Carbon
Total Sulfide
Priority Organic Pollutants
1,1,1 -Trichloroethane
1 , 1 -Dichloroethane
1 , 1 -Dichloroethylene
2,4-Dimethylphenol
2,4-Dinitrophenol
Di-n-Butyl Phthalate
Di-n-Octyl Phthalate
Dimethyl Phthalate
Ethylbenzene
Fluoranthene
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7.0 - Selection of Pollutant Parameters
Table 7-15 (Continued)
2,6-Dinitrotoluene
2-Nitrophenol
4-Chloro-m-cresol
Fluorene
Isophorone
Methylene Chloride
Priority Organic Pollutants (continued)
4-Nitrophenol
Acenaphthene
Acrolein
Anthracene
Benzyl Butyl Phthalate
Bis(2-Ethylhexyl) Phthalate
Chlorobenzene
Chloroethane
Chloroform
n-Nitrosodimethylamine
n-Nitrosodiphenylamine
Naphthalene
Phenanthrene
Phenol
Pyrene
Tetrachloroethene
Toluene
Trichloroethylene
Nonconventional Organic Pollutants
1 -Methylfluorene
1 -Methylphenanthrene
2-Isopropylnaphthalene
2-Methylnaphthalene
3 ,6-Dimethy Iphenanthrene
Aniline
Benzoic Acid
Biphenyl
Carbon Bisulfide
Dibenzofuran
Dibenzothiophene
n-Hexadecane
n-Tetradecane
p-Cymene
7.2.2.1
Oily Wastes Subcategory
For the direct dischargers in the Oily Wastes subcategory, EPA is proposing effluent
limitations for all of the pollutants listed in Table 7-15 except for BOD5. EPA is proposing an effluent
limitation for O&G and TOC for this subcategory and therefore determined that BOD5 would be
controlled by the regulation of these parameters. For the organic parameters listed in Table 7-14,
facilities in the Oily Wastes subcategory may choose from the following three options in order to
comply with the regulation: comply with the limit for TOC; comply with the limit for TOP; or implement
an organic pollutant management plan. Section 14 lists the effluent limitations for direct dischargers in
the Oily Wastes subcategory.
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7.0 - Selection of Pollutant Parameters
7.2.2.2 Railroad Line Maintenance Subcategory
For the direct dischargers in the Railroad Line Maintenance subcategory, EPA is
proposing effluent limitations for all of the pollutants listed in Table 7-15 except for TOC, total sulfide,
and all of the priority and nonconventional pollutants (represented as TOP). EPA is proposing effluent
limitations for O&G and BOD5 for this subcategory and therefore determined that TOC and the priority
and nonconventional organic pollutants would be controlled by the regulation of these parameters. EPA
is not proposing an effluent limit for total sulfide in this subcategory because of the small quantity of this
pollutant removed by proposed technology. EPA estimates that the regulation of total sulfide for the
Railroad Line Maintenance subcategory would result in the removal of 7.3 Ibs/year or less than 0.2
Ibs/facility. Section 14 lists the effluent limitations for the direct dischargers in the Railroad Line
Maintenance subcategory.
7.2.2.3 Shipbuilding Dry Dock Subcategory
For the direct dischargers in the Shipbuilding Dry Dock subcategory, EPA is proposing
effluent limitations for all of the pollutants listed in Table 7-15 except for BOD5, TOC, total sulfide, and
all of the priority and nonconventional pollutants (represented as TOP). EPA is proposing effluent
limitations for O&G for this subcategory and therefore determined that BOD5, TOC, and the priority
and nonconventional organic pollutants would be controlled by the regulation of O&G. EPA is not
proposing an effluent limit for total sulfide in this subcategory because of the small quantity of this
pollutant removed by the proposed technology. Many of the facilities in this subcategory already have
treatment in place, and therefore, the MP&m rule achieves very little additional removal of total sulfide.
EPA estimates that the regulation of total sulfide for the Shipbuilding Dry Dock subcategory would
result in the removal of less than 1 Ib/yr. Section 14 lists the effluent limitations for the direct
dischargers in the Shipbuilding Dry Dock subcategory.
7.3 Pollutants Proposed to be Regulated for Indirect Dischargers
For indirect dischargers, before proposing national technology-based pretreatment
standards, EPA examines whether the pollutants discharged by an industry "pass through" POTWs to
waters of the U.S. or interfere with POTW operation or sludge disposal practices. Section 307(b) of
the CWA requires EPA to promulgate pretreatment standards for existing sources (PSES) and new
sources (PSNS). The Agency establishes pretreatment standards to ensure removal of pollutants that
pass through or interfere with POTWs. EPA evaluated POTW pass-through for the MP&M pollutant
parameters of concern listed in Tables 7-10 and 7-15.
Sections 7.3.2 and 7.3.3 discuss the results of the pass-through analysis for exiting and
new sources, respectively.
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7.0 - Selection of Pollutant Parameters
7.3.1 Pass-through Analysis for Indirect Dischargers
Generally, to determine if pollutants pass through POTWs, EPA compares the
percentage of the pollutant removed by well-operated POTWs achieving secondary treatment with the
percentage of the pollutant removed by direct discharging industrial facilities applying BAT for that
pollutant. The Agency determines that a pollutant "passes through" the POTW when the average
percentage removed by POTWs nationwide is less than the percentage removed by direct discharging
industrial facilities applying the BAT technology basis. In this manner, EPA can ensure that the
combined treatment at indirect discharging facilities and POTWs is at least equivalent to that obtained
through treatment by a direct discharger using BAT technology.
EPA compares removals for two reasons: (1) to ensure that wastewater treatment
performance for indirect dischargers is equivalent to that for direct dischargers, and (2) to recognize
and take into account the treatment capability and performance of the POTW in regulating the
discharge of pollutants from indirect dischargers. Rather than compare the mass or concentration of
pollutants discharged by POTWs with the mass or concentration of pollutants discharged by BAT
facilities, EPA compares the percentage of the pollutants removed by BAT facilities to the POTW
removals. EPA takes this approach because a comparison of the mass or concentration of pollutants in
POTW effluents with pollutants in BAT facility effluents would not take into account the mass of
pollutants discharged to the POTW from other industrial and non-industrial sources, nor the dilution of
the pollutants in the POTW to lower concentrations from the addition of large amounts of other
industrial and non-industrial water.
EPA conducted the pass through removal comparison on the priority and
nonconventional metal pollutants regulated under BAT for each subcategory. The Agency did not
perform this assessment for the regulated conventional pollutants, namely BOD5, TSS, and O&G, since
the conventional pollutants are generally not regulated under PSES and PSNS. EPA also did not
perform the pass through analysis for the priority and nonconventional organic pollutants that comprise
the TOP nor did it perform the analysis for TOC. Since EPA is proposing limitations for TOP and
TOC as part of an organic indicator option for direct dischargers, the Agency also decided that it was
appropriate to propose the same organic indicator alternatives for indirect dischargers. Similarly, the
Agency did not perform the pass-through analysis for amenable cyanide. EPA is proposing a limit for
direct dischargers for amenable cyanide as an alternative to total cyanide as a way to provide
monitoring flexibility. The Agency decided that it was appropriate to propose the same cyanide
monitoring alternatives for indirect dischargers as those proposed for directs, and therefore, it did not
perform the pass-through analysis for amenable cyanide.
The primary source of the POTW percent removal data is the "Fate of Priority
Pollutants in Publicly Owned Treatment Works" (EPA 440/1-82/303, September 1982), commonly
referred to as the "50-POTW Study." This study presents data on the performance of 50 well-
operated POTWs that employ secondary biological treatment in removing pollutants. Each sample was
analyzed for three conventional, 16 non-conventional, and 126 priority toxic pollutants. EPA used
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7.0 - Selection of Pollutant Parameters
percent removals data from the 50-POTW Study for all of the pollutants for which EPA applied the
pass-through analysis (i.e., those pollutants proposed for regulation at BAT).
In using the 50-POTW Study data to estimate percent removals, EPA has established
data editing criteria for determining pollutant percent removals. Some of the editing criteria are based
on differences between POTW and industry BAT treatment system influent concentrations. For many
toxic pollutants, POTW influent concentrations were much lower than those of BAT treatment systems.
For many pollutants, particularly organic pollutants, the effluent concentrations from both POTW and
BAT treatment systems were below the level that could be found or measured. As noted in the 50-
POTW Study, analytical laboratories reported pollutant concentrations below the analytical threshold
level, qualitatively, as "not detected" or "trace," and reported a measured value above this level.
Subsequent rulemaking studies such as the 1987 OCPSF study used the analytical method nominal
minimum level (ML) established in 40 CFR Part 136 for laboratory data reported below the analytical
threshold level. Use of the nominal ML may overestimate the effluent concentration and underestimate
the percent removal.
At the time of the 50-POTW sampling program, which spanned approximately 2.5
years (July 1978 to November 1980), EPA collected samples at selected POTWs across the U.S.
The samples were subsequently analyzed by either EPA or EPA-contract laboratories using test
procedures (analytical methods) specified by the Agency or in use at the laboratories. Laboratories
typically reported the analytical method used along with the test results. However, for those cases in
which the laboratory specified no analytical method, EPA was able to identify the method based on the
nature of the results and knowledge of the methods available at the time.
Each laboratory reported results for the pollutants for which it tested. If the laboratory
found a pollutant to be present, the laboratory reported a result. If the laboratory found the pollutant
not to be present, the laboratory reported either that the pollutant was "not detected" or a value with a
"less than" sign (<) indicating that the pollutant was below that value. The value reported along with the
"less than" sign was the lowest level to which the laboratory believed it could reliably measure. EPA
subsequently established these lower levels as the MLs of quantitation. In some instances, different
laboratories reported different (sample-specific) MLs for the same pollutant using the same analytical
method.
Because of the variety of reporting protocols among the 50-POTW Study laboratories
(pages 27 to 30, 50-POTW Study), EPA reviewed the percent removal calculations used in the pass-
through analysis for previous industry studies, including those performed when developing effluent
guidelines for Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) Manufacturing, Centralized
Waste Treatment (CWT), and Commercial Hazardous Waste Combustors. EPA found that, for 12
parameters, different analytical MLs were reported for different rulemaking studies (10 of the 21
metals, cyanide, and one of the 41 organics).
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7.0 - Selection of Pollutant Parameters
To provide consistency for data analysis and establishment of removal efficiencies, EPA
reviewed the 50-POTW Study, standardized the reported MLs for use in the final rules for CWT and
Transportation Equipment Cleaning Industries and for this proposed rule and the Iron and Steel
proposed rule. A more detailed discussion of the methodology used and the results of the ML
evaluation are contained in the MP&M public record.
Because the data collected for evaluating POTW percent removals included both
effluent and influent levels that were close to the analytical detection levels, EPA devised hierarchal data
editing criteria to exclude data with low influent concentration levels, thereby minimizing the possibility
that low POTW removals might simply reflect low influent concentrations instead of being a true
measure of treatment effectiveness.
EPA has generally used hierarchic data editing criteria for the pollutants in the 50-
POTW Study. For the MP&M proposal, as in previous rulemakings, EPA used the following editing
criteria:
1) Delete both influent and effluent data on a given date if either datum has a notation
of analytical interference;
2) Substitute a pollutant-specific analytical "minimum level" for values "reported as "not
detected," "trace," "less than [followed by a number]," or a number" less than the
analytical minimum level established by the reporting laboratory;
3) Delete pollutants that have fewer than three pairs of data points (influent/effluent);
4) Delete pollutant influent and corresponding effluent values if the average pollutant
influent level is less than 10 times the pollutant minimum level; and
5) If none of the average pollutant influent concentrations exceeded 10 times the ML,
then delete average influent values less than 20 • g/1 or twice the ML (2XML) along
with the corresponding average effluent values.
EPA then calculates each POTW percent removal for each pollutant based on its
average influent and its average effluent values. The national POTW percent removal used for each
pollutant in the pass-through test is the median value of all the POTW pollutant specific percent
removals.
The rationale for retaining POTW data using the "lOxML" editing criterion is based on
the BAT organic pollutant treatment performance editing criteria initially developed for the 1987
OCPSF regulation (52 FR 42522, 42545-48; November 5, 1987). BAT treatment system designs in
the OCPSF industry typically achieved at least 90 percent removal of toxic pollutants. Since most of
the OCPSF effluent data from BAT biological treatment systems had values of "not detected," the
average influent concentration for a compound had to be at least 10 times the analytical minimum level
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7.0 - Selection of Pollutant Parameters
for the difference to be meaningful (demonstration of at least 90 percent removal) and qualify effluent
concentrations for calculation of effluent limits.
EPA is evaluating several issues related to its traditional methodology for determining
POTW performance and explains these issues in detail in Appendix A to this Section.
7.3.2
Pass-through Analysis Results for Existing Sources
For each of the MP&M subcategories, EPA calculated the percentage of a pollutant
removed by BAT treatment systems using the median percent removal achieved by BAT facilities that it
used for determining effluent limitations for direct dischargers. To determine pass-through, it compared
this median percent removal for BAT facilities to the median percent removal determined from the 50-
POTW database. Table 7-16 presents the results of the pass-through analysis for the metal-bearing
wastewater subcategories.
Table 7-16
Pass-Through Analysis Results for Existing Sources for Metal-Bearing
Wastewater Subcategories
Pollutant
Amenable Cyanide (a)
Cadmium
Chromium
Copper
Cyanide (a)
Lead
Manganese
Molybdenum
Nickel
Silver
Tin
Zinc
Median BAT Percent Removal by Subcategory
General Metals
99.6
92.2
99
95.8
99.1
99.4
96.9
64.7
96.3
94.8
98.8
98
Metal Finishing
Job Shops
99.6
98.8
96.7
95.9
99.1
99.6
98.8
64.7 (b)
93.7
96.5
97.8
97.1
Non-
Chromium
Anodizing
NA
NA
NA
NA
NA
NA
96.9 (b)
NA
96.3 (b)
NA
NA
98.0 (b)
Printed Wiring
Boards
99.6
NA
99.0 (b)
96.3
99.1
99.4 (b)
57.7
NA
89.3
NA
98.1
98.0 (b)
Steel Forming
and Finishing
(b)
99.6
92.2
99
95.8
99.1
99.4
96.9
64.7
96.3
94.8
98.8
98
Median
POTW
Percent
Removal (c)
57.4
90.1
80.3
84.2
70.4
77.5
35.5
18.9
51.4
88.3
42.6
79.1
(a) EPA determined BAT percent removals for Total Cyanide using data from all subcategories.
(b) EPA transferred BAT percent removal from General Metals Subcategory.
(c) All POTW percent removals determined from 50-POTW Study.
NA = Pollutant not proposed for BAT regulation for the specific Subcategory therefore pass through analysis does
not apply.
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7.0 - Selection of Pollutant Parameters
EPA compared the BAT percent removals and the POTW percent removals shown in
Table 7-16 and determined that all of these pollutants pass through POTWs. In addition to the
pollutants listed in Table 7-16, EPA is proposing pretreatment standards for Total Sulfide for the
General Metals, Metal Finishing Job Shops, Printed Wiring Board, and Steel Forming and Finishing
subcategories. The Agency is proposing a limitation for total sulfide based on potential POTW
interference or upset associated with discharges of this pollutant from MP&M facilities (i.e., through
corrosion of pipes from formatting sulfuric acid or hazardous conditions to POTW employees from
generation of hydrogen sulfide gas). EPA is also proposing pretreatment standards for TOC and TOP
as part of a compliance alternative for organic pollutant discharges. See Section 15.2.6 for a discussion
of the proposed monitoring alternatives for organic pollutants. Section 14 lists the pretreatment
standards for the pollutants proposed for regulation for indirect dischargers in each of the
subcategories.
For the three subcategories that generate primarily oil-bearing wastewater (Oily
Wastes, Railroad Line Maintenance, and Shipbuilding Dry Dock), EPA is only establishing
pretreatment standards for the Oily Wastes subcategory. For the reasons discussed in detail in Section
14, EPA is not proposing pretreatment standards for the Railroad Line Maintenance nor the
Shipbuilding Dry Dock subcategories. For the Oily Wastes subcategory, EPA is proposing
pretreatment standards for TOP, TOC and total sulfide. The Agency is proposing a limitation for total
sulfide based on potential POTW interference or upset associated with discharges of this pollutant from
MP&M facilities. EPA is also proposing pretreatment standards for TOC and TOP as part of a
compliance alternative for organic pollutant discharges. See Section 15.2.6 for a discussion of the
proposed monitoring alternatives for organic pollutants. Section 14 lists the pretreatment standards for
the pollutants proposed for regulation for indirect dischargers in the Oily Wastes subcategory.
7.3.3 Pass-through Analysis Results for New Sources
For each of the MP&M subcategories, EPA calculated the percentage of a pollutant
removed by NSPS treatment systems using the median percent removal achieved by NSPS facilities
that it used for determining effluent limitations for new direct dischargers. To determine pass-through, it
compared this median percent removal for NSPS facilities to the median percent removal determined
from the 50-POTW database. Table 7-17 presents the results of the pass-through analysis for the
metal-bearing wastewater subcategories:
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Table 7-17
Pass-Through Analysis Results for New Sources for Metal-Bearing
Wastewater Subcategories
Pollutant
Cadmium
Chromium
Copper
Cyanide (a)
Lead
Manganese
Molybdenum
Nickel
Silver
Tin
Zinc
Median NSPS Percent Removal by Subcategory
General Metals
99.8
99.4
97.8
99.1
99.4 (b)
96.3
64.7 (b)
97.6
99.4
98.5
99.8
Metal
Finishing Job
Shops
99.8 (d)
99.4 (d)
97.8 (d)
99.1
99.4 (b)
96.3 (d)
64.7 (b)
97.6 (d)
99.4 (d)
98.5 (d)
99.8 (d)
Non-
Chromium
Anodizing (d)
NA
NA
NA
NA
NA
96. 9 (b)
NA
96.3 (b)
NA
NA
98.0 (b)
Printed
Wiring Boards
NA
99.4 (d)
100
99.1
99.1
96.3 (d)
NA
97.6 (d)
NA
98.9
99. 8 (d)
Steel Forming
and Finishing
(d)
99.8
99.4
97.8
99.1
99.4
96.3
64.7
97.6
99.4
98.5
99.8
Median POTW
Percent
Removal (c)
90.1
80.3
84.2
70.4
77.5
35.5
18.9
51.4
88.3
42.6
79.1
(a) EPA determined NSPS percent removals for Total Cyanide using data from all subcategories.
(b) EPA transferred BAT percent removal from General Metals Subcategory.
(c) All POTW percent removals determined from 50-POTW Study.
(d) EPA transferred NSPS percent removals from General Metals Subcategory.
NA = Pollutant not proposed for NSPS regulation for the specific Subcategory therefore pass through analysis does
not apply.
EPA compared the NSPS percent removals and the POTW percent removals shown
in Table 7-17 and determined that all of these pollutants pass through POTWs. In addition to the
pollutants listed in Table 7-17, EPA is proposing pretreatment standards for new sources for Total
Sulfide for the General Metals, Metal Finishing Job Shops, Printed Wiring Board, and Steel Forming
and Finishing subcategories. The Agency is proposing a limitation for total sulfide based on potential
POTW interference or upset associated with discharges of this pollutant from MP&M facilities (i.e.,
through corrosion of pipes from formation of sulfuric acid or hazardous conditions to POTW employees
from generation of hydrogen sulfide gas). EPA is also proposing pretreatment standards for new
sources for TOC and TOP as part of a compliance alternative for organic pollutant discharges. See
Section 15.2.6 for a discussion of the proposed monitoring alternatives for organic pollutants. Section
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7.0 - Selection of Pollutant Parameters
14 lists the pretreatment standards for new sources for the pollutants proposed for regulation for
indirect dischargers in each of the subcategories.
For the reasons described in Section 14, EPA is proposing pretreatment standards for
new sources (PSNS) for the Oily Wastes subcategory equivalent to those proposed for existing
sources. In addition, the Agency also explains in Section 14 its rationale for not proposing PSNS for
the Railroad Line Maintenance and the Shipbuilding Dry Docks subcategories.
7.4 References
1. U.S. Environmental Protection Agency. The 1990 Industrial Technology Division List
of Analvtes. Washington, DC, May 1990.
2. U.S. Environmental Protection Agency. Development Document for the Centralized
Waste Treatment Industry, December 1998.
3. U.S. Environmental Protection Agency. Fate of Priority Pollutants in Publicly Owned
Treatment Works. EPA-440/1-82/303. Washington DC, September 1982.
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Appendix A
Proposed Revisions to the Methodology Used to Determine
POTW Performance for Toxic and Non-Conventional Pollutants
For the MP&M proposal, EPA used its traditional methodology to determine POTW
performance (percent removal) for toxic and non-conventional pollutants. POTW performance is a
component of the pass-through methodology used to identify the pollutants to be regulated for PSES
and PSNS. It is also a component of the analysis to determine net pollutant reductions (for both total
pounds and toxic pound-equivalents) for various indirect discharge technology options. However, as
discussed in more detail below, EPA is considering revisions to its traditional methodology for
determining POTW performance (percent removals) for toxic and non-conventional pollutants. In the
traditional methodology, the pertinent data selection editing criteria used to determine POTW percent
removals were based on the editing criteria used for industry data to calculate BAT limitations.
However, since POTWs are designed to treat conventional pollutants, not toxic pollutants, the revised
editing criteria would more accurately reflect the incidental removals of toxic pollutants in POTWs.
Background
Unlike direct dischargers whose wastewater will receive no further treatment once it
leaves the facility, indirect dischargers send their wastewater streams to POTWs for further treatment.
However, POTWs typically install secondary biological treatment systems which are designed to
control conventional pollutants [biochemical oxygen demand (BOD), total suspended solids (TSS), oil
& grease (O&G), pH, and fecal coliform] — the principal parameters for characterizing domestic
sewage. With the exception of nutrient control for ammonia and phosphorus, POTWs usually do not
install specific technology (advanced or tertiary treatment) to control toxic and non-conventional
pollutants, although incidental removals in secondary biological treatment systems may be significant for
some toxic pollutants. Instead, the Clean Water Act envisions that, through implementation of
pretreatment programs and industrial compliance with categorical pretreatment standards, toxic and
non-conventional pollutants in municipal effluents will be controlled adequately.
Therefore, for indirect dischargers, before proposing national technology-based
pretreatment standards, EPA examines whether the pollutants discharged by an industry "pass through"
POTWs to waters of the U.S. or interfere with POTW operation or sludge disposal practices.
Generally, to determine if pollutants pass through POTWs, EPA compares the percentage of the
pollutant removed by well-operated POTWs achieving secondary treatment with the percentage of the
pollutant removed by direct discharging industrial facilities applying BAT for that pollutant. A pollutant
is determined to "pass through" the POTW when the average percentage removed by POTWs
nationwide is less than the percentage removed by direct discharging industrial facilities applying the
BAT technology basis. In this manner, EPA can ensure that the combined treatment at indirect
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discharging facilities and POTWs is at least equivalent to that obtained through treatment by a direct
discharger using BAT technology.
For specific pollutants, such as volatile organic compounds, EPA may use other means
to determine pass-through. These evaluations may include chemical and physical properties (e.g.,
Henry's Law constants, octanol/water partition coefficients, and water solubility constants) and
empirical data to estimate amounts of volatilization, biodegradation, and/or partitioning to the residue
solids phase.
Traditional Methodology for Determination of POTW Percent Removals
The primary source of the POTW data is the "Fate of Priority Pollutants in Publicly
Owned Treatment Works" (EPA 440/1-82/303, September 1982), commonly referred to as the "50-
POTW Study." At most of these POTWs, EPA collected a minimum of 6 days of 24-hour composite
influent and effluent wastewater samples. EPA analyzed each sample for the conventional pollutants
(excluding fecal coliform), selected non-conventional pollutants, and the 126 priority pollutants. The
conventional pollutants, listed at 40 CFR 401.16, are BOD5,TSS, O&G, pH, and fecal coliform. The
selected non-conventional pollutants included chemical oxygen demand, total organic carbon, total
phenols, ammonia nitrogen, iron, aluminum, and magnesium, among several others. The priority
pollutants consist of the 126 compounds (listed in Appendix A of 40 CFR Part 423) that are a subset
of the 65 toxic pollutants and classes of pollutants referred to in Section 307(a) of the Clean Water Act
and listed at 40 CFR 401.15. A total of 102 of the 126 priority toxic pollutants were detected at least
once in POTW influents (page 1, 50-POTW Study).
In using the 50-POTW Study data to estimate percent removals, EPA established data
editing criteria for determining pollutant percent removals. Some of the editing criteria are based on
differences between POTW and industry BAT treatment system influent concentrations. For many
pollutants, POTW influent concentrations were much lower than those of BAT treatment systems. For
many pollutants, particularly organic pollutants, the effluent concentrations from both POTW and BAT
treatment systems, were below the level that could be found or measured. As noted in the 1982 50-
POTW Study, analytical laboratories reported pollutant concentrations below the analytical minimum
level, qualitatively, as "not detected" or "trace," and reported a measured value above this level (pages
27 to 30). Subsequent rulemaking studies such as the 1987 OCPSF study used the analytical method
"minimum level" (ML) established in 40 CFR Part 136 for laboratory data reported below the
analytical threshold level. Use of the ML may overestimate the effluent concentration and
underestimate the percent removal. (If the actual effluent concentration is less than the ML, then the
calculated percent removal based on the actual value would be higher.) Because the data collected for
evaluating POTW percent removals included both effluent and influent levels that were close to the
analytical MLs, EPA devised hierarchal data editing criteria to exclude data with low influent
concentration levels, thereby minimizing the possibility that low POTW removals might simply reflect
low influent concentrations instead of being a true measure of treatment effectiveness.
7-36
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7.0 - Selection of Pollutant Parameters
EPA has generally used the following hierarchic data editing criteria1 for the pollutants in
the 50-POTW Study:
1) Delete both influent and effluent data on a given date if either datum has a notation of
analytical interference,
2) Substitute a pollutant-specific analytical "minimum level" for values reported as "not
detected", "trace", "less than [followed by a number]", or a number less than the
analytical minimum level established by the reporting laboratory,
3) Delete pollutants that have fewer than three pairs of data points (influent/effluent),
4) Delete pollutant influent and corresponding effluent values if the average pollutant
influent level is less than 10 times the pollutant ML, and
5) If none of the average pollutant influent concentrations exceeded lOxML, then delete
average influent values less than 20 • g/1 or twice the minimum level (2xML) along with
the corresponding average effluent values.
EPA then calculated each POTW percent removal for each pollutant based on its
average influent and its average effluent values. The POTW percent removal used for each pollutant in
the pass-through test was the median value of all the POTW pollutant specific percent removals.
The rationale for retaining POTW data using the "10 times the pollutant minimum level"
editing criterion was based on the BAT organic pollutant treatment performance editing criteria initially
developed for the 1987 organic chemicals, plastics, and synthetic fibers (OCPSF) regulation (40 CFR
Part 414; 52 FR 42522 at 42545 to 48). BAT treatment system designs in the OCPSF industry
typically achieved at least 90 percent removal of toxic pollutants. Since most of the OCPSF effluent
data from BAT biological treatment systems had values of "not detected,"2 the average influent
concentration for a compound had to be at least 10 times the analytical ML for the difference to be
meaningful (demonstration of at least 90 percent removal) and qualify effluent concentrations for
calculation of effluent limits ("OCPSF DD," Vol. I, page VII-183).
1 These 50-POTW Study data editing criteria may vary among effluent guideline development studies.
2 Of the 57 regulated organic pollutants, limits for 34 (60 percent) were based on long-term averages of "not
detected" or the analytical minimum level ("Development Document for Effluent Limitations Guidelines and
Standards for the Organic Chemicals, Plastics, and Synthetic Fibers Point source Category" - the "OCPSF DD,"
(EPA 440/1-87/009), October 1987, Vol. I, pages VII-208 to VTl-210).
7-37
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7.0 - Selection of Pollutant Parameters
Review of the 50-POTW Study Analytical Laboratory Reporting Practices and Standardization
of Minimum Level Values
At the time of the 50-POTW sampling program which spanned approximately 2 1A
years (July 1978 to November 1980), EPA collected samples at selected POTWs across the U.S.
The samples were subsequently analyzed by either EPA or EPA-contract laboratories using test
procedures (analytical methods) specified by the Agency or in use at the laboratories. Laboratories
typically reported the analytical method used along with the test results. However, for those cases in
which the laboratory specified no analytical method, EPA was able to specify the method based on the
nature of the results and knowledge of the methods available at the time.
To provide consistency for data analysis and establishment of removal efficiencies, EPA
reviewed the 50-POTW Study, standardized the reported MLs for use in the CWT final rule and the
MP&M proposal. EPA standardized the MLs based on information about the analytical methods used,
laboratory capabilities at the time the testing was conducted (1978 to 1980), MLs that had been
achievable historically, and consultation with Agency experts in the field of analytical chemistry. The
standardized MLs are used in this reassessment.
Reassessment of the Pass-Through Methodology and Revised Editing Criteria
The Agency has reevaluated several aspects of the 50-POTW Study data base editing
process and is considering changes to the editing criteria. Several minor editing criteria changes that
EPA is considering for use in the final MP&M pretreatment standard including those related to the
presence of analytical interferences, missing data, reported greater-than values, and reported less-than
values higher than the MLs are described in Appendix B, "Revised Data Conventions for the 50-
POTW Study Analytical Data." To compare the proposed changes to the traditional editing criteria
used for the MP&M proposal, additions to the criteria are highlighted as "(New)" and revisions to
existing criteria are highlighted as "(Revised)."
The principal editing criterion of the pass-through analysis used for the MP&M
proposal — using available performance data representing average influent concentrations 10 times the
analytical ML. This is also the primary editing criteria for ensuring that promulgated effluent limitations
guidelines and standards are based only on the performance of BAT wastewater treatment systems
with meaningful influent concentrations of pollutants. This editing criterion ensures that BAT data would
demonstrate at least 90 percent removal of toxic pollutants. EPA selected this criterion for the POTW
data for similar reasons. However, after reconsidering the design differences between industrial BAT
treatment and POTW treatment systems as well as the differences in toxic pollutant influent
concentrations, EPA believes that the "lOxML" editing criterion is too restrictive for the purpose of
analyzing POTW data, especially where effluent values are above the ML.
7-38
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7.0 - Selection of Pollutant Parameters
The majority of discharging POTWs (67 percent) have installed secondary biological
treatment systems3 designed to treat conventional pollutants characteristic of domestic sewage
(primarily BOD5 and TSS). Most POTWs with secondary treatment have installed a variation of the
activated sludge biological process with typical wastewater hydraulic residence times ranging from 4 to
8 hours for the most prevalent process designs.4 Very few secondary POTWs install unit operations
specifically designed to remove toxic and non-conventional pollutants.5
In contrast, depending on raw waste characteristics, industrial treatment systems are
often designed to remove toxic pollutants using a wide variety of in-plant wastewater treatment unit
operations with or without end-of-pipe secondary biological treatment systems and sometimes followed
by tertiary controls. For example, plants in the MP&M, electroplating, iron and steel, OCPSF,
inorganic chemicals, landfills, commercial hazardous waste combustor, centralized waste treatment and
other industries may use in-process or end-of-pipe chemical precipitation for metals control, alkaline
chlorination for cyanide control, steam or air stripping for volatile organic pollutant control, and
activated carbon or biological treatment for control of a wide variety of organic pollutants. For plants in
the OCPSF industry with end-of-pipe secondary biological treatment systems, the median and average
wastewater hydraulic residence times are 48 and 118 hours, respectively.6 Most of the pollutant-
specific treatment unit operations listed above are not used to treat POTW wastewater because of the
relatively low influent toxic pollutant concentrations. POTW toxic pollutant influent concentrations are
often orders of magnitude lower than industrial raw waste concentrations.
Because of these design and toxic pollutant influent concentration differences, the
POTW data editing criteria should reflect typical incidental removals of toxic pollutants in secondary
biological treatment systems designed and operated to control municipal sewerage. In general, due to
3 The 1996 Clean Water Needs Survey found that of the 13,992 discharging POTWs, 1.3 percent reported less than
secondary treatment, 67.1 percent reported secondary treatment, and the remaining 31.6 percent reported better than
secondary treatment (www.epa.gov/owm/uc.htm at Appendix C).
4 Hydraulic residence times for the conventional and tapered aeration activated sludge processes range from 4 to 8
hours; for the step aeration and contact stabilization processes, from 3 to 6 hours; for the modified and high-rate
aeration processes, from 0.5 to 3 hours; and for the extended aeration process, from 18 to 36 hours (1992 WEF
Manual of Practice No. 8, page 627, Vol. I).
5 Typical POTW unit operations include preliminary treatment (screening and grit removal), primary treatment
(sedimentation, sludge collection, and odor control), and secondary treatment (biological treatment with secondary
clarification). POTW unit operations associated with advanced or tertiary treatment include nutrient controls
(phosphorus and nitrogen [including ammonia] removal processes), multi-media filtration, and activated carbon (1992
WEF Manual of Practice No. 8, pages 389, 447, 517, and 675, Vol. I and pages 895 and 1013, Vol. II).
6 Based on 31 OCPSF biological treatment systems with residence times ranging from 4.5 to 1,008 hours
("Development Document for Effluent Limitations Guidelines and Standards for the Organic Chemicals, Plastics, and
Synthetic Fibers Point source Category," (EPA 440/1-87/009), October 1987, Vol. II, page VIII-45 and "Supplement to
the Development Document for Effluent Limitations Guidelines and Standards for the Organic Chemicals, Plastics,
and Synthetic Fibers Point source Category," (EPA 821-R-93-007), May 1993, pages 111-20 to 23).
7-39
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7.0 - Selection of Pollutant Parameters
dilution in municipal sewer collection systems, POTW influent concentrations of toxic pollutants are
lower than the influent concentrations of industrial treatment systems. In those cases where both
industrial and municipal treatment systems reduce the effluent pollutant concentration to the analytical
ML, the relative performance - percent removal — is primarily a function of the influent concentrations.
This was the principal reason for initially using the "lOxML" influent editing criterion for retaining
POTW average performance data - to avoid the bias of calculating artificially low median percent
removals (median of POTW average performance). However, this editing criterion, when applied to
the 50-POTW Study data, overestimates POTW incidental removals for many toxic pollutants. In the
50-POTW Study data base, there are many cases where POTW average influent concentrations are
less than the "lOxML" editing criterion and the average effluent data are above the ML. These cases
should be included in the calculation of national POTW performance (median of POTW average
percent removals) because they accurately reflect the incidental removals of the toxic pollutants in
treatment systems primarily designed for the control of conventional pollutants. For example, for many
POTWs in the study, average metal pollutant influent concentrations less than "lOxML" are paired with
average effluent concentrations where each data point is measured above the analytical ML. Because
of these pairings, EPA can accurately calculate the incidental removals of toxic pollutants characteristic
of POTW designs and the characteristically low POTW toxic pollutant influent concentrations. EPA
believes it is reasonable to include these percent removal calculations in its pass-through analysis.
Furthermore, one of the observations and conclusions in the 50-POTW Study was that
for many pollutants, "as influent concentrations increased effluent concentrations also increased. This
implies that the removal rates for the priority pollutants are relatively constant and a fixed percentage of
incremental loadings of these pollutants will be removed by secondary treatment." Therefore, except
for highly biodegradable compounds, for typical POTW secondary biological treatment designs without
specific unit operations for toxic pollutant control, one would not necessarily expect the percent
removals of toxic pollutants to increase (above incidental removal levels) as influent concentrations
increased.
Assessment of Editing Criteria for 50-POTW Performance by Treatment Technology
EPA is also considering incorporating POTW treatment system and BOD5/TSS
performance editing criteria into the methodology for determining POTW performance (percent
removal) for toxic and non-conventional pollutants.
A major goal of the 50-POTW study was to obtain toxic priority pollutant data from
representative types of secondary treatment facilities that would exist after completion of EPA's
Construction Grants program. The 50 POTWs selected for sampling are representative of biological
treatment processes - 35 activated sludge, 8 trickling filter, 4 activated sludge with parallel trickling
filter, 1 rotating biological contactor, 1 aerated lagoon, and 1 lagoon system. Eight of these POTWs
include post-secondary or tertiary treatment (4 filtration and 4 lagoon systems).
7-40
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7.0 - Selection of Pollutant Parameters
The 50-POTW Study and subsequent assessments of POTW performance (including
the assessment for the MP&M proposal) used combined end-of-pipe data for all 50 POTWs. The
analyses did not assess potential differences in toxic pollutant reductions among the various types of
secondary systems, between secondary and tertiary systems, and among different levels of BOD5 and
TSS control (the principal design basis for POTW treatment systems).
After publication of the 50-POTW Study, EPA promulgated its Secondary Treatment
Regulation (40 CFR Part 133) to provide information on the level of effluent quality attainable through
the application of secondary or equivalent treatment. Secondary treatment generally refers to activated
sludge biological processes and treatment equivalent to secondary treatment refers to trickling filters or
waste stabilization ponds. The secondary treatment performance criteria for both BOD5 and TSS are
30-day and 7-day averages not exceeding 30 mg/1 and 45 mg/1, respectively. The BOD5 and TSS
criteria for equivalent secondary treatment for both BOD5 and TSS are 30-day and 7-day averages not
exceeding 45 mg/1 and 65 mg/1, respectively. These definitions and treatment levels provide the basis
for the technology and BOD5/TSS performance edits being proposed for use in the final rule.
The revised analyses under consideration include separating the data collected for the 4
parallel activated sludge and trickling filter systems and, for 2 of the tertiary systems, including the
secondary activated sludge sampling data. This expands the performance data base to 56 POTW
treatment trains - 41 activated sludge, 12 trickling filter, 1 rotating biological contactor, 1 aerated
lagoon, and 1 lagoon system. Again, 8 of these treatment trains include secondary or tertiary treatment
(4 filtration and 4 lagoon systems). Based on the definitions in 40 CFR Part 133, the POTW treatment
trains consist of 47 secondary or equivalent systems, 1 rotating biological contactor, and 8 post-
secondary or tertiary systems. The Agency is considering a variety of POTW treatment train and
BODj/TSS performance editing criteria to determine if these factors significantly affect the incidental
removals of toxic and non-conventional pollutants in POTWs. For example, among other alternatives,
EPA is considering editing criteria that would retain only those secondary or equivalent treatment trains
and the rotating biological contactor treatment train that meet the BOD5/TSS 7-day average
performance criteria. EPA is considering this alternative because it accounts for the fact that only 6
days of data were collected at each POTW.
Revised Editing Criteria for Determining POTW Performance
Based on these concerns, EPA is considering revising the POTW toxic and non-
conventional pollutant performance (percent removal) editing criteria. Given the range of analytical
MLs7 and their influence on calculated percent removals as well as the range of in-place POTW
treatment technology, EPA is considering several editing alternatives including:
7 For most organic pollutants, the ML is 10 (ig/1 (several have MLs of 20 and 50 (ig/1). For mercury, silver, cadmium,
zinc, copper, nickel, lead, and barium, the respective MLs are 0.2, 2, 5, 20, 25, 40, 50, and 200 (ig/1.
7-41
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7.0 - Selection of Pollutant Parameters
Alternative A - For POTW treatment trains that meet the 7-day conventional pollutant
performance criteria for BOD5 (45 mg/1 or lower) and TSS (45 mg/1 or lower) using
secondary activated sludge biological treatment or its equivalent:
1. If all effluent values are equal to the ML and the ML is less than or equal to 20 jig/1,
retain the pollutant performance (percent removal) if the pollutant influent average is at
least ten times the nominal minimum level (lOxML).
2. If all effluent values are equal to the ML and the ML is greater than 20 mg/1, retain
the pollutant performance (percent removal) if the pollutant influent average is at least
ten times one-half the nominal minimum level [10 x (O.SxML) or 5 x ML].
3. If the effluent average is greater than the ML, retain the pollutant performance
(percent removal) regardless of the pollutant influent average.
4. The national POTW/pollutant percent removal is the median of the retained values
from 1, 2, and 3 above.
Alternative B — The same as Alternative A for items Al, A2, and A4 with the following
modification to item A3: If the effluent average is greater than the ML, retain the
pollutant performance (percent removal) if the pollutant influent average is at least two
times the nominal minimum level (2xML). Based on the analyses conducted to date,
this is the Agency's preferred alternative.
Alternative C - Retain all toxic pollutant data for POTW treatment trains that meet the
7-day conventional pollutant performance criteria for BOD5 (45 mg/1 or lower) and
TSS (45 mg/1 or lower) using secondary activated sludge biological treatment or its
equivalent.
Alternative D — The same as Alternative B with the following modifications: (a) Retain
POTW treatment trains with secondary biological treatment (as designated by treatment
flag "S"), only if both the effluent BOD5 and TSS average concentrations are less than
or equal to 45 mg/1. (b) Retain POTW treatment trains with equivalent to secondary
biological treatment (as designated by treatment flag "E"), only if both the effluent
BOD5 and TSS average concentrations are less than or equal to 65 mg/1.
Alternative E — The same as Alternative D with the following modification:
substitute O.SXML for all data points set equal to the analytical ML.
Table A-l lists the national POTW percent removals for several pollutants, determined
by using the traditional methodology for the proposal (Column 2), Alternative A (Column 3),
Alternative B (Column 4), Alternative C (Column 5), Alternative D (Column 6), and Alternative E
7-42
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7.0 - Selection of Pollutant Parameters
(Column 7). For the proposal, EPA has used the traditional methodology to estimate POTW percent
removals, and, therefore, whether these pollutants "pass through" for purposes of selecting pollutants
for regulation by PSES and PSNS. EPA solicits comments on its pass-through methodology, including
the revised editing criteria discussed above as well as for other alternatives.
Assessment of the Use of Analytical Minimum Levels
Since some commenters have concerns that EPA's use of the ML for reported effluent
data of
-------
7.0 - Selection of Pollutant Parameters
The 28 organic pollutants retained by the Alternative D data conventions were divided
into low, medium, and high Henry's Law Constant groups. For the six organics with low Henry's Law
Constants (10"3 to 10"8), about 81 percent of the 38 POTW/organic pollutant effluent data sets in the
table are comprised of all NC (18 percent) and a mixture of NC & ND (63 percent) values. For the
nine organics with medium Henry's Law Constants (10"1 to 10"3), about 83 percent of the 36
POTW/organic pollutant effluent data sets in the table are comprised of all NC (25 percent) and a
mixture of NC & ND (58 percent) values. For the 13 organics with high Henry's Law Constants
(2xl02 to 10"1), about 83 percent of the 73 POTW/organic pollutant effluent data sets in the table are
comprised of all NC (19 percent) and a mixture of NC & ND (64 percent) values.
The Agency concludes that POTW performance for metals, ammonia, cyanide, and
organic pollutants is not significantly affected by the bias of effluent data being less than the MLs.
7-44
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7.0 - Selection of Pollutant Parameters
Table A-l - Comparison of 50-POTW Study Removal Estimation Alternatives (Median Percent
Removals)
Pollutant
Parameter
Ammonia
Cyanide
Antimony
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Mercury
Nickel
Silver
Tin
Zinc
Naphthalene
Phenol
Traditional
Method
%
39
70
67
90
80
84
82
77
36
90
51
88
43
79
95
95
Alternative
A
%
40
65
47
86
76
80
82
48
24
63
28
67
20
77
95
95
Alternative
B
%
40
66
57
89
77
80
82
57
24
63
29
69
41
77
95
96
Alternative
C
%
40
60
10
37
76
80
82
55
24
60
32
69
39
77
39
70
Alternative
D
%
39
65
57
89
76
79
80
57
23
61
29
67
41
76
95
96
Alternative
E
%
39
65
57
89
77
80
82
69
23
73
29
73
47
76
97
97
Analytical
ML
ng/i
10
20
20
5
10
25
100
50
15
0.2
40
2
30
20
10
10
7-45
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7.0 - Selection of Pollutant Parameters
Table A-2 - Number of POTWs Retained by Alternative D Data
Conventions
Analyte
CAS No.
Total
Number
POTWs
Effluent "All
NC"
Effluent Mix
(NCandND)
Effluent
"A11ND"
Class=Metals, Tech Group=E or S
Aluminum
Antimony
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Silver
Sodium
Tin
Titanium
Vanadium
Yttrium
Total
7429905
7440360
7440428
7440439
7440702
7440473
7440484
7440508
7439896
7439921
7439954
7439965
7439976
7439987
7440020
7440224
7440235
7440315
7440326
7440622
7440655
31
1
6
6
36
34
1
34
43
7
22
40
15
2
14
17
21
o
J
10
2
2
73
11
1
4
2
35
23
0
13
34
2
22
38
4
1
9
5
21
1
1
2
0
14
16
0
2
4
1
11
1
17
9
4
0
2
11
1
5
12
0
2
9
0
2
47
4
0
0
0
0
0
0
4
0
1
0
0
0
0
0
0
0
0
0
0
0
12
7-46
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Table A-2 (Continued)
7.0 - Selection of Pollutant Parameters
Analyte
CAS No.
Total
Number
POTWs
Effluent "All
NC"
Effluent Mix
(NCandND)
Effluent
"A11ND"
Class=Nonconventional, Tech Group=E or S
Ammonia as N
Total Cyanide
Total
7664417
57125
35
30
65
35
27
62
0
3
3
0
0
0
Class=Organics LOW, Tech Group=E or S
Bis(2-
ethylhexyl)phthalate
Butyl benzyl phthalate
Di-n-butyl phthalate
Di-n-octyl phthalate
Fluoranthene
Phenol
Total
117817
85687
84742
117840
206440
108952
25
1
2
2
1
7
38
6
0
0
0
0
1
7
19
0
2
2
1
0
24
0
1
0
0
0
6
7
Class=Organics MED, Tech Group=E or S
Acenaphthene
Anthracene
Methylene chloride
Naphthalene
Phenanthrene
1 ,2-Dichlorobenzene
1 ,2-Dichloroethane
1 ,2-Dichloropropane
1 ,2,4-Trichlorobenzene
Total
83329
120127
75092
91203
85018
95501
107062
78875
120821
2
2
22
1
2
2
2
1
2
36
0
0
7
0
0
0
2
0
0
9
1
1
15
0
1
1
0
0
2
21
1
1
0
1
1
1
0
1
0
6
7-47
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Table A-2 (Continued)
7.0 - Selection of Pollutant Parameters
Analyte
CAS No.
Total
Number
POTWs
Effluent "All
NC"
Effluent Mix
(NCandND)
Effluent
"A11ND"
Class=Organics HIGH, Tech Group=E or S
Benzene
Chlorobenzene
Chloroform
Chloromethane
Dichlorodifluoromethane
Ethylbenzene
Tetrachloroethene
Tetrachloromethane
Toluene
Trans- 1 ,2-Dichloroethene
Trichlorethene
Vinyl chloride
1,1,1 ,-Trichloroethane
71432
108907
67663
74873
75718
100414
127184
56235
108883
156605
79016
75014
71556
Total
5
1
5
2
1
5
15
1
11
2
10
1
14
347
0
0
2
0
1
0
4
1
0
0
4
0
2
229
2
0
3
2
0
5
9
0
9
2
4
1
10
109
3
1
0
0
0
0
2
0
2
0
2
0
2
9
Source: U.S. EPA, 50-POTW Study, 1982.
Tech Group E = POTWs that achieve effluent BOD5/TSS concentrations less than or equal to 65 mg/1.
Tech Group S = POTWs that achieve effluent BOD/TSS concentrations less than or equal to 45 mg/1.
Class Organics_LOW = Organics with Henry's Law Constant between 10"8 and 10"3.
Class Organics_MED = Organics with Henry's Law Constant between 10"3 and 10"1.
Class Organics_HIGH = Organics with Henry's Law Constant between 10"1 and IxlO2.
7-48
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7.0 - Selection of Pollutant Parameters
Appendix B
Revised Data Conventions
for the "50-POTW Study" Analytical Data
1. (New) Applied an alpha-numeric naming convention to identify parallel treatment trains
within a POTW. The naming convention is composed of the POTW's number and a
suffix. For example, POTW 10 has two parallel treatment trains. The applied
convention designates these trains as 10A and 10B. Records associated with treatment
train "A" in POTW 10 all carry the designation 10A. If a POTW has only one
treatment train, then, with one exception, all records for the POTW are identified by the
POTW number. No suffix is applied. In the case of POTW 56, a sampling point is
designated after primary clarification (56A) and after tertiary filtration (56B). Samples
were not collected after the secondary activated sludge treatment unit. The traditional
data conventions - used for the MP&M proposal - averaged all of the respective
influent and effluent values for parallel treatment systems.
2. (New) Added treatment technology codes and technology flags. Treatment Technology
codes include "AS" for activated sludge, "TF" for trickling filter, "RBC" for rotating
biological contactor, lagoon, and primary clarifier. Some POTWs use a combination of
treatments such as AS + tertiary oxidation ponds. When treatment technologies are
used in combination, the combination is identified. Technology flags are: "P" for
primary treatment; "S" for secondary biological treatment; "E" for equivalent to
secondary biological treatment; and "T" for secondary biological or equivalent
treatment systems with tertiary treatment unit operations.
3. This placeholder ensures consistency between the computer output headings and these
data conventions. (The numbered statements correspond to preliminary drafts of the
revised data conventions. Some data conventions contained in earlier drafts were
mistaken or misplaced in sequence and EPA removed these conventions from
subsequent drafts. However, EPA retained the assigned number sequence because of
reference to these numbers in the computer listings. Thus, this number is effectively
blank.)
4. Converted the units of measure for each pollutant to a common metric.
5. (Revised) Deleted individual data points for a pollutant if supporting records indicated
that one of the following conditions was met (corresponding to key codes 4, 5, 6, and 8
described at the end of this appendix):
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7.0 - Selection of Pollutant Parameters
a. Analytical interference prevented the determination of the presence or
quantification of the pollutant (key code = 4),
b. Analytical interference was indicated, but the pollutant concentration was not
recorded above the concentration reported (key code = 5),
c. No chemical analysis was conducted or the result of the chemical analysis was
not reported (key code = 6), and
d. The pollutant was qualitatively present but not quantified or confirmed (key
code = 8).
e. (Revised) Deleted the record results from a "right censored" qualitative
method. These records are identified as "greater-than (>) X" where "X" is a
method specific value. This indicator signifies that the recorded measure is the
lower bound of the amount of the pollutant in the sample. The traditional data
conventions - used for the MP&M proposal — reported ">values" as the
value. (If calculations are based on influent ">values," then the percent
removals would be lower than they should be. If calculations are based on
effluent ">values," then the percent removals would be higher than they should
be.)
The revised data conventions delete pollutant concentration data points on an individual
basis, not in pairs. For example, if the influent data point meets one of the previously
identified conditions, it is deleted. Its paired effluent data point is not deleted unless it
too meets one of the conditions. The traditional data conventions deleted data in daily
pairs.
6. Incorporated the standardized analytical "minimum level" (ML) values for each record.
These values were assigned based on a determination of the analytical method
employed and the precision and accuracy of the 1978 to 1980 analytical methods used
to measure the pollutant.
7. (Revised) Deleted records reported as "< values" that are greater than the ML. This
may occur when samples are diluted to reduce analytical matrix interference. If a
pollutant is not detected in the diluted sample, the resulting ML is multiplied by the
dilution factor. (For data reported as "< values," this rule initially set the value to the
ML for calculation purposes without considering if the value is greater than the ML.
For influent value substitutions, the traditional editing rule decreases calculated
performance. For effluent value substitutions, it increases calculated performance.)
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7.0 - Selection of Pollutant Parameters
8. Set equal to the pollutant analytical ML, any remaining pollutant values reported as
non-detect (key codes 1,3, Ind 7):
a. Less than the concentration listed (key code = 1),
b. Detected, but not quantified at lower than the concentration listed (key code =
3), and
c. "Not-detected" (key code = 7),
9. For detected or non-censored (NC) values reported as less than the ML, set the value
equal to the ML and report the value as a non-detect.
10. (New) If the pollutant ML is GREATER THAN 20, substituted O.SxML for influent
and effluent samples if all effluent values are equal to the ML and the value was a non-
detect. The following pollutants are excluded from this convention: BOD5, COD,
O&G, TDS, TOC, Total Solids, and TSS.
11. Retain pollutant data for a POTW if there are at least three (3) influent concentration
values reported and at least one of the reported influent values is measured above the
ML for the pollutant.
12. This placeholder ensures consistency between the computer output headings and these
data conventions. (The numbered statements correspond to preliminary drafts of the
revised data conventions. Some data conventions contained in earlier drafts were
mistaken or misplaced in sequence and EPA removed these conventions from
subsequent drafts. However, EPA retained the assigned number sequence because of
reference to these numbers in the computer listings. Thus, this number is effectively
blank.)
13. (New) Retain POTW treatment trains with secondary biological treatment or
equivalent (as designated by treatment flags "S" or "E", only if both the effluent BOD5
and TSS average concentrations are less than or equal to 45 mg/1.
14. (Revised) Retain non-negative percent removals that are greater than zero for a given
pollutant where the percent removal = (100)(ave influent - ave effluent)/ave influent.
The traditional data conventions retained zero percent removals. (The medians of these
intermediate values are referred to as Alternative C.)
15. Identify three (overlapping) subsets of POTWs based on the average influent
concentration:
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7.0 - Selection of Pollutant Parameters
a. (i.) If all effluent values are equal to the ML and the ML is greater than 20 ppb,
retain the pollutant performance (percent removal) if the pollutant influent
average is at least ten times one-half the nominal minimum level [10x( O.SxML)
= 5xML].
(ii) If all effluent values are equal to the ML and the ML is less than or equal to
20 ppb, retain the pollutant performance (percent removal) if the pollutant
influent average is at least ten times the nominal minimum level (10 x ML).
b. If the effluent average is greater than the ML, retain the pollutant performance
(percent removal) regardless of the pollutant influent average.
16. The national POTW/pollutant percent removal is the median of the retained values from
ISA and 15B above. (This is referred to as Alternative A.)
17. Modify 15B: If the effluent average is greater than the ML, retain the pollutant
performance (percent removal) if the pollutant influent average is at least two times the
nominal minimum level (2xML).
18. Modify 16: The national POTW/pollutant percent removal is the median of the retained
values from ISA and 17 above. (This is referred to as Alternative B.)
19. Modify 13: (a) Retain POTW treatment trains with secondary biological treatment (as
designated by treatment flag "S"), only if both the effluent BOD5 and TSS average
concentrations are less than or equal to 45 mg/1. (b) Retain POTW treatment trains
with equivalent to secondary biological treatment (as designated by treatment flag "E"),
only if both the effluent BOD5 and TSS average concentrations are less than or equal to
65 mg/1. (c) The national POTW/pollutant percent removal is the median of the
retained values from 15 A and 17 above. (This is referred to as Alternative D.)
20. Modify 19: Substitute O.SxML for all data points set equal to the analytical ML. (This
is referred to as Alternative E.)
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7.0 - Selection of Pollutant Parameters
Description of the Key Codes (See pages 29 & 30, 50-POTW Study) used to qualify analytical results
in the 50-POTW Data Set.
CODE
CONCENTRATION
MEANING OF CODE
0
1
2
any
any
any
detected at this concentration
less than this concentration
detected at greater than (>) this
concentration
any
detected, but not quantified at lower
than this concentration
any value >0
analytical interference prevented
determination of the presence or
prevented quantification of the analyte
analytical interference was present, but
concentration was estimated as this
concentration
any
analytical interference was present, but
the analyte was not detected above this
concentration
6
7
0
0 or blank
0
any value >0
no analysis was run or reported
reported as "not detected"
analyte was detected, but could not be
quantified
a pesticide was detected by GC-ECD
at this concentration, but GC-MS did
not confirm the presence of the analyte
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
8.0 POLLUTION PREVENTION PRACTICES AND WASTEWATER
TREATMENT TECHNOLOGIES
This section presents an overview of pollution prevention practices and
wastewater treatment technologies in the MP&M industry. Section 8.1 describes pollution
prevention practices, Section 8.2 describes technologies used for the preliminary treatment of
waste streams, and Section 8.3 describes end-of-pipe wastewater treatment and sludge
dewatering technologies. This section discusses the most prevalent technologies in place at
MP&M facilities, including all the technologies used as a basis for the MP&M effluent
guidelines. However, additional technologies may be applicable for some MP&M facilities,
depending on the waste streams generated. Additionally, not all technologies discussed in this
section are applicable to all MP&M sites; the technology applicability is driven by the processes
performed and waste streams generated on site.
8.1 Pollution Prevention Practices
Pollution prevention practices reduce the generation or discharge of pollutants and
therefore potentially reduce treatment or disposal costs. Typical pollution prevention practices
include reducing water use, extending the life of process bath constituents, or adding recycling or
reuse technologies. This section divides pollution prevention practices into three categories.
Section 8.1.1 discusses flow reduction practices, Section 8.1.2 discusses in-process pollution
prevention technologies, and Section 8.1.3 describes additional methods of pollution prevention.
8.1.1 Flow Reduction Practices
Flow reduction practices are applied to process baths or rinses to reduce the
amount of wastewater discharged. Flow reduction practices consist of optimizing rinse tank
design and configuration and installing flow reduction technologies such as flow restrictors or
timers. The following sections discuss flow reduction practices in greater detail.
8.1.1.1 Rinse Tank Design and Innovative Configurations
Rinsing follows many MP&M unit operations to remove dirt, oil, or chemicals
(i.e., drag-out) remaining on parts or racks from a previous unit operation. Rinsing improves the
quality of the surface finishing process and prevents the contamination of subsequent process
baths. Rinse tank design and rinsing configuration are important factors influencing water usage.
The key objectives of optimal rinse tank design are to quickly remove drag-out from the part and
to disperse the drag-out throughout the rinse tank.
The MP&M industry uses various rinsing configurations. The use of single
overflow rinse tanks following each process tank is the most inefficient use of rinse water.
Multiple rinse tanks connected in series (i.e., cascade rinsing) reduce the water needs of a given
rinsing operation by one or more orders of magnitude (i.e., less water is needed to achieve the
same rinsing criterion). Spray rinsing can also be used to reduce water use requirements, but the
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
achievable percent reduction of water use is usually less than for countercurrent cascade rinses.
A description of some of the common rinse types is provided below.
Cascade rinsing
Cascade rinsing is a method of reusing rinse water. Rinse water from one rinsing
operation is plumbed to another, less critical rinsing operation before being discharged to
treatment. Some rinse waters acquire chemical properties, such as low pH, that make them
desirable for reuse in other rinse systems. For example, an acid treatment rinse may be plumbed
to an alkaline treatment rinse, providing both drag-out removal and neutralization.
Countercurrent Cascade Rinsing
Countercurrent cascade rinsing refers to a series of consecutive rinse tanks which
are plumbed to cause water to flow from one tank to another in the direction opposite of the work
flow. Fresh water flows into the rinse tank located farthest from the process tank and overflows,
in turn, to the rinse tanks closer to the process tank. This technique is termed countercurrent
rinsing, because the work piece and the rinse water move in opposite directions. Over time, the
first rinse becomes contaminated with drag-out and reaches a stable concentration which is lower
than the process solution. The second rinse stabilizes at a lower concentration, which enables
less rinse water to be used than if only one rinse tank were in place. Increasing the number of
countercurrent cascade rinse tanks (three-stage, four-stage, etc.), reduces the amount of water
needed to adequately remove the process solution. Figure 8-1 shows the application of
countercurrent cascade rinsing.
work movement ^~ —
incoming water
Figure 8-1. Countercurrent Cascade Rinsing
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
The rinse rate needed to adequately dilute drag-out depends on the concentration
of process chemicals in the drag-out, the concentration of chemicals that can be tolerated in the
final rinse tank before poor rinse results are obtained, and the number of countercurrent cascade
rinse tanks. These factors are expressed in the following equation (2):
cf
\ ^ I
1/n
(8-1)
where:
Vr
C0
Cf
V
the flow through each rinse stage, gal/min;
the concentration of the contaminant(s) in the initial process bath,
mg/L;
the tolerable concentration of the contaminant(s) in the final rinse
to give acceptable product cleanliness, mg/L;
the number of rinse stages used; and
the drag-out carried into each rinse stage, expressed as a flow,
gal/min.
This mathematical rinsing model is based on complete rinsing (i.e., removal of all
contaminants from the part/fixture) and complete mixing (i.e., homogeneous rinse water). Under
these conditions, each additional rinse stage can reduce rinse water use by 90 percent. These
conditions are not achieved unless there is sufficient residence time and agitation in each rinse
tank. For less efficient rinse systems, each added rinse stage reduces rinse water use by 50 to 75
percent.
Countercurrent cascade rinsing systems have higher capital costs than overflow
rinses and require more space to accommodate the additional rinse tanks. Also, when
countercurrent cascade rinsing is used, the low flow rate through the rinse tanks may not provide
the needed agitation for drag-out removal. In such cases, air or mechanical agitation may be
added to increase rinsing efficiency.
Drag-out Rinsing
A drag-out rinse is a stagnant rinse, initially filled with fresh water, positioned
immediately after the process tank. Parts are rinsed in drag-out tanks directly after exiting the
process bath. The drag-out rinse collects the majority of the drag-out from the process tank, thus
preventing it from entering the subsequent flowing rinses and therefore reducing pollutant
loadings in those rinses. Gradually, the concentration of process chemicals in the drag-out tank
rises. In the most efficient configuration, a drag-out tank follows a heated process tank that has a
moderate to high evaporation rate. A portion of the fluid in the drag-out tank returns the process
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
tank to replace the evaporative loss. The level of fluid in the drag-out tank is maintained by
adding fresh water. Electrolytic recovery of dissolved metals from drag-out tanks is also
common.
Spray Rinsing
For certain part configurations, spray rinsing uses considerably less water than
immersion rinsing. Spray rinsing can be performed in a countercurrent cascade configuration,
further reducing water use. Spray rinsing can enhance draining over a process bath by diluting
and lowering the viscosity of the process fluid film clinging to the parts.
8.1.1.2 Additional Rinse Design Elements
In addition to rinse configuration, other modifications can be made to the process
line to reduce drag-out of process bath chemicals. For example, air knives and drip tanks reduce
the pollutant loading and amount of rinsewater requiring treatment. Other aspects of good rinse
tank design include positioning the water inlet and discharge points of the tank at opposite
locations in the tank to avoid short-circuiting, using air agitation for better mixing, using a flow
distributor, and using the minimum tank size possible (5). EPA describes several additional rinse
design elements in more detail below.
Air Knives
Air knives are usually installed over a process tank or drip shield and are designed
to remove drag-out by blowing it off the surface of parts and racks. Drag-out is routed back to
the process tank. Air knives are most effective with flat parts and cannot be used to dry surfaces
that passivate or stain due to oxidation.
Drip Shields
Drip shields are installed between process tanks and rinse tanks to recover process
fluid dripping from racks and barrels that would otherwise fall into rinse tanks or onto the floor.
Often, drip shields are an inclined piece of polypropylene or other material which is inert to the
metal finishing process.
Drip Tanks
Drip tanks are similar to drag-out tanks except they are not filled with water.
Parts exiting a process bath are held over the drip tank and the process fluid that drips from the
parts is collected in the tank. When enough fluid is collected in the drip tank, the fluid is
returned to the process tank.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
Long Dwell Time
Automatic lines can be programmed to include optimum drip times. Long dwell
times over the process tank reduce the volume of drag-out reaching the rinsing system. On
manual lines, racks can be hung on bars over process baths to allow time to drip. Barrels can be
rotated over the process bath to enhance drainage. Increases in drip time may be unsuitable for
surfaces that can be oxidized or stained by exposure to air.
8.1.1.3 Rinse Water Use Control
Facilities can reduce water use by coordinating and closely monitoring rinse water
requirements (e.g., rinse water use is optimized based on drag-out rates so that the rinse criterion
is consistently achieved). Matching water use to rinse water requirements optimizes the quantity
of rinse water used for a given work load and tank arrangement (5). Inadequate control of water-
use negates the benefits of using multiple rinse tanks or employing other water conservation
practices and results in a high water usage.
Many sites use some form of rinse water control. The four most common
methods are flow restrictors (these can be used with other methods to regulate the rate at which
water is dispensed), manual control (i.e., turning water valves on and off as needed), conductivity
controls, and timer rinse controls. These are discussed below.
Flow Restrictors
A flow restrictor prevents the flow in a pipe from exceeding a predetermined flow
rate. Flow restrictors are commonly installed on a rinse tank's water inlet. These devices contain
an elastomer washer which flexes under pressure to maintain a constant water flow regardless of
pressure. Flow restrictors can maintain a wide range of flow rates, from less than 0.1 gal/min to
more than 10 gal/min. As a stand-alone device, a flow restrictor provides a constant water flow.
As such, for intermittent rinsing operations, a flow restrictor does not coordinate the rinse flow
with drag-out introduction. Precise control with intermittent operations typically requires a
combination of flow restrictors and rinse timers. However, for continuous rinsing (e.g.,
continuous electroplating machines), flow restrictors may be adequate for good water use control.
Conductivity Meters
Conductivity probes measure the conductivity of water in a rinse tank to regulate
the flow of fresh rinse water into the rinse system. Conductivity controllers consist of a
controller, a meter with adjustable set points, a probe that is placed in the rinse tank, and a
solenoid valve. As parts are rinsed, dissolved solids enter the water in the rinse tank, raising the
conductivity of the water. When conductivity reaches a set point where the bath can no longer
provide effective rinsing, the solenoid valve opens to allow make-up water to enter the tank.
When the conductivity falls below the set point, the valve closes to discontinue the make-up
water flow.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
In theory, conductivity control of rinse flow is a precise method of maintaining
optimum rinsing conditions in intermittently used rinse operations. In practice, conductivity
controllers work best with deionized rinse water. Incoming water conductivity may vary day-to-
day and season-to-season, which forces frequent set point adjustments. In addition, suspended
solids and nonionic contaminants (e.g., oil) can cause inadequate rinsing and are not detected by
the conductivity probe.
Rinse Timers
Rinse timers are electronic devices that control a solenoid valve. The timer
usually consists of a button that, when pressed, opens the valve for a predetermined length of
time, usually from 1 to 99 minutes. After the time period has expired, the valve is automatically
closed. The timer may be activated either manually by the operator or automatically by the
action of racks or hoists. Automatic rinse timers are generally preferred for intermittent rinses
since they eliminate operator error. Rinse timers installed in conjunction with flow restrictors
can provide precise control when the incoming water pressure may rise and fall. Rinse timers are
less effective in continuous or nearly continuous rinse operations (e.g., continuous electroplating
machines).
8.1.1.4 Pollution Prevention for Process Baths
Facilities can also implement pollution prevention technologies for process baths
to reduce the pollutant loadings and therefore the amount of rinse water required. EPA gives
several examples of pollution prevention technologies for process baths below.
Temperature
Temperature and viscosity are inversely related; therefore, operating at the highest
possible bath temperature will lower viscosity and reduce drag-out.
Lower Concentration
Operating at the lowest possible concentration reduces the mass of chemicals in a
given volume of drag-out. Also, viscosity and concentration are directly related; therefore, lower
process bath concentration will result in lower viscosity and less drag-out volume. Contaminants
and other process bath impurities should be minimized, if possible.
Wetting Agents
Wetting agents or surfactants may be added to some process baths to reduce
viscosity and surface tension, thereby significantly reducing drag-out.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
8.1.2 In-Process Pollution Prevention Technologies
This section describes in-process pollution prevention technologies used in the
MP&M industry. Not all technologies discussed in this section are applicable to all MP&M
sites. The pollution prevention practices that are included in the MP&M technology options are
listed in Section 9.0.
In-process pollution prevention technologies can be applied to process baths or
rinses. Process baths become contaminated with impurities that affect their performance. The
sources of process bath contamination include: (1) breakdown of process chemicals; (2) buildup
of byproducts (e.g., carbonates); (3) contamination from impurities in make-up water, chemicals,
or anodes; (4) corrosion of parts, racks, tanks, heating coils, etc.; (5) drag-in of chemicals; (6)
errors in bath additions; and (7) airborne particles entering the tank. If not properly maintained,
process baths eventually become unusable and require disposal. Regeneration and maintenance
techniques help keep baths in good operating condition, thereby extending the useful lives of
process solutions. Use of these technologies reduces the pollutant loading to the wastewater
treatment system, which in turn reduces wastewater treatment chemical purchases and sludge
disposal costs.
This section describes the following technologies:
• Activated carbon adsorption;
• Carbonate freezing;
• Centrifugation and pasteurization of machining coolants;
• Centrifugation and recycling of painting water curtains;
• Electrodialysis;
• Electrolytic recovery;
• Evaporation;
• Filtration;
• Ion exchange; and
• Reverse osmosis.
8.1.2.1 Activated Carbon Adsorption
Activated carbon adsorption of electroplating baths is a common method of
removing organic contaminants. Process solution flows through a filter where the carbon
adsorbs organic impurities that result from the presence of oils or cleaners from the breakdown of
bath constituents. Carbon adsorption can be used on either a continuous or batch basis,
depending on the site's preference. Carbon treatment is most commonly applied to nickel,
copper, zinc, and cadmium electroplating but can also be used to recycle paint curtain
wastewater.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
8.1.2.2 Carbonate "Freezing"
Carbonate "freezing" removes excessive carbonate buildup by forming carbonate
salt crystals at a low temperature. This process is most often applied to electroplating baths
formulated with sodium cyanide. Carbonates build up in the process bath by the breakdown of
cyanide (especially at high temperatures) and the adsorption of carbon dioxide from the air. An
excessive carbonate concentration reduces the quality of many metal finishing operations.
Carbonate "freezing" takes advantage of the low solubility of carbonate salts in the sodium
cyanide bath. The method lowers the bath temperature to approximately 26°F (-3°C), at which
point hydrated salt (Na2CO3»10H2O) crystallizes out of solution. The crystallized carbonate can
be removed by decanting the fluid into another tank or by filtration.
8.1.2.3 Centrifugation and Pasteurization of Machining Coolants
Most machining coolants consist of water-soluble oil in water. The water-soluble
coolant is typically pumped through a sump, over the machining tool and part during machining,
and back to the sump. Over a period of time, coolant becomes ineffective, or spent, for one or
more of the following reasons:
• The concentration of suspended solids in the coolant begins to inhibit
performance;
• Nonemulsified, or "tramp", oil collects on the surface of the coolant;
• The coolant becomes rancid due to microbial growth; or
• Coolant additives are consumed by drag out and organic breakdown, thus
reducing corrosion prevention and lubrication properties.
Machining coolant can be recycled using a centrifugal separator and
pasteurization unit. Centrifugation removes the solids from the coolant to extend its usable life.
The separator is a rotating chamber that uses centrifugal force to push the coolant through a mesh
chamber, leaving behind the contaminants. Sludge is scraped from the centrifuge and collected
in a sludge hopper. Some high speed centrifuges can also perform liquid - liquid separation for
the removal of tramp oils. The coolant is pasteurized after separation to kill the microorganisms
that cause bacterial growth. Bacterial growth can also be controlled by addition of a biocide.
Figure 8-2 shows a diagram of a typical machine coolant recycling system.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
Recycled Coolant
Holding Tank
Recycled
Coolant to
Process
Figure 8-2. Machine Coolant Recyclying System
Centrifugal separators are very reliable and require only routine maintenance, such
as periodic cleaning and removal of accumulated solids. Flow rate is the primary operating
factor to control. The sludge generated from this technology is commonly classified as a
hazardous waste, based on the metal type processed and the amount of metal that dissolves into
the coolant. The sludge is typically contract hauled for treatment and disposal.
Coolant recycling is most effective when sites minimize the number of different
coolants used on site and use a centralized coolant recycling system. However, some sites may
not be able to use a single recycling system because of multiple coolant types required by product
or customer specifications. In this case, sites may need to purchase dedicated coolant recycling
systems for each type of coolant used.
Centrifugation and pasteurization can be used along with oil skimming and
biocide addition to reduce coolant discharge and pollutant generation at the source. Oil
skimming using a vertical belt system removes large amounts of tramp hydraulic oils floating on
the surface of the machine coolant. Oil skimming and biocide addition can further extend the
life of water-soluble coolant, thereby reducing the amount of coolant and wastewater requiring
treatment and disposal, and minimizing the amount of fresh coolant purchased.
8.1.2.4
Centrifugation and Recycling of Painting Water Curtains
Water curtains are a continuous flow of water behind the part being spray painted
in a paint booth. The water traps paint overspray and is continuously recirculated in the paint
curtain until the solids content in the wastewater necessitates either in-process treatment and
recycling or discharge. Centrifugal separators remove the solids and recycle the water curtain,
eliminating the need for discharge. In this system, wastewater is pumped to a holding tank, then
through the centrifugal separator, which separates the solids from the wastewater (see section
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Chemical Addition
(if necessary!
8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
Recycled Water
Paint Solids
to Contract Haul
Figure 8-3. Centrifugation and Recycling of Painting Water Curtains
8.1.2.3). Solids are contract hauled for off-site disposal, while the treated wastewater is returned
to the paint booth. Detactifiers may be added before centrifugation to increase the solid
separation efficiency.
Centrifugation of the paint curtain proceeds until all wastewater is treated and
only sludge remains in the sump. The sludge in the water curtain sump must be removed either
manually, with a sludge pump, or by a vacuum truck. After the sludge has been removed and the
wastewater has been treated through the centrifuge, the wastewater from the holding tank is
pumped back into the water curtain sump. Make-up water is added to compensate for
evaporation. Using this procedure, the paint curtain water can be continuously recycled. Figure
8-3 shows a flow diagram of a typical paint curtain centrifugation and recycling system.
Wastewater from painting water curtains commonly contains organic pollutants as
well as certain metals. Eliminating the discharge of wastewater from painting water curtains may
eliminate the need for an end-of-pipe treatment step for organic pollutants at certain sites. Also,
if a site generates only painting wastewater and continuously recycles the wastewater, the site
would not need end-of-pipe wastewater treatment.
As discussed in Section 8.1.2.3, centrifugal separators are very reliable and
require only routine maintenance. Flow rate is the primary operating factor to control. One
disadvantage of this technology is that it may not be economically feasible for sites generating
only a small amount of paint curtain wastewater. Sites that have multiple sumps can use portable
centrifuges.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
The sludge generated from painting water curtains is commonly classified as a
hazardous waste, based on the type of paint used, and is typically contract hauled for treatment
and disposal.
8.1.2.5
Electrodialysis
Electrodialysis is a membrane technology used to remove impurities from process
solutions. A direct current is applied across a series of alternating anion and cation exchange
membranes to remove dissolved metal salts and other ionic constituents from solutions.
An electrodialysis unit consists of a rectifier and a membrane stack. The rectifier
converts alternating current to direct current. The stack consists of alternating anion- and cation-
specific membranes which form compartments. As the feed stream enters the unit, ions move
across the electrodialysis membranes, forming a concentrated stream and a deionized stream.
When the compartments are filled, a direct current is applied across each membrane in the stack.
Cations traverse one cation-specific membrane in the direction of the cathode and are trapped in
that concentrate compartment by the next membrane, which is anion-specific. Anions from the
neighboring compartment traverse the anion-specific membrane in the direction of the anode,
joining the cations, and are likewise trapped in the concentrate compartment by the next cation-
specific membrane. In this way, the feed stream is depleted of ions, and anions and cations are
trapped in each concentrate compartment. Electrodialysis is typically used to remove metal ions
from electroplating wastewater. Figure 8-4 shows a diagram of an electrodialysis cell.
Cathode Transfer
Membrane
Anion Transfer
Membrane
Cathode Transfer
Membrane
Figure 8-4. Electrodialysis Cell
8.1.2.6
Electrolytic Recovery
Electrolytic recovery is an electrochemical process used to recover metals from
many types of process solutions and rinses, such as electroplating rinse waters and baths.
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Electrolytic recovery removes metal ions from a waste stream by processing the stream in an
electrolytic cell, which consists of a closely spaced anode and cathode. Commercial equipment
consists of one or more cells, a transfer pump, and a rectifier. Current is applied across the cell
and metal cations are deposited on the cathodes. The waste stream is usually recirculated
through the cell from a separate tank, such as a drag-out recovery rinse.
Electrolytic recovery is typically applied to solutions containing either nickel,
copper, precious metals, or cadmium. Chromium cannot be electrolytically recovered because it
exists primarily in anionic forms such as dichromate. Aluminum is also a poor candidate for
electrolytic recovery. Drag-out recovery rinses and ion-exchange regenerant are solutions that
are commonly processed using electrolytic recovery. Some solutions require pH adjustment prior
to electrolytic recovery. Acidic, metal-rich, cation regenerant is an excellent candidate stream for
electrolytic recovery and is often electrolytically recovered without pH adjustment. In some
cases, when the target metal concentration is reached, the waste stream may be reused as cation
regenerant.
The capacity of electrolytic recovery equipment depends on the total cathode area
and the maximum rated output of the rectifier. Commercial units are available with a cathode
area ranging from 1 ft2 to 100 ft2 or larger, and an output of 10 to 1,000 amperes or more.
Theoretical electrolytic recovery rates are determined by Faraday's law which states the amount
of chemical change produced by an electric current is proportional to the quantity of electricity
used. Theoretical recovery rates range from 1.09 grams/amp-hour for nickel to 7.35 grams/amp-
hour for monovalent gold. Actual rates are usually much lower and depend on the metal
concentration in the waste stream. At concentrations under 100 mg/L, electrolytic recovery rates
may be below 10 percent of the theoretical maximum.
Various types of cathodes are used in electrolytic recovery units, depending
mainly on the concentration of metal in the waste stream. Cathodes are often classified by their
surface area. Flat-plate cathodes have the lowest surface area and are used only for recovering
metal from metal-rich waste streams (usually 1,000 to 20,000 mg/L of metal). Reticulate
cathodes, which have a metallized woven fiber design, have a surface area ten times greater than
their apparent area. These cathodes are effective over a wide range of metal concentrations but
are typically used where the dissolved metal concentration is below 100 mg/L. Carbon and
graphite cathodes have the highest surface area per unit of apparent area. Their use is usually
restricted to metal concentrations below 1,000 mg/L.
Dissolved metals in electrolytes can be recovered to low levels (<5 mg/L) using
reticulate or carbon cathodes. In practice, however, the target concentration for most applications
is 50 to 250 mg/L or higher because of the time and energy required to achieve concentrations
less than 100 mg/L. With flat-plate cathodes, the target concentration is usually above 500 mg/L,
because plating efficiency drops as concentration falls. Plating time required to lower the
concentration of a pollutant from 100 to 10 mg/L can be several times longer than that required
to lower the concentration from 10,000 mg/L to 100 mg/L. Also, unit energy costs (measured in
dollars per pound of metal recovered) increase substantially at lower metal concentrations.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
Labor requirements are relatively low for electrolytic recovery. Units recovering
metal from drag-out recovery tanks may only require occasional cleaning and maintenance.
Units treating batch discharges from ion-exchange units require more labor due to the higher
metal content of the solution and the resultant increase in cathode loading frequency. Energy
costs for this technology can be high, and, in some cases, exceed the recovery value of the metal.
Energy requirements depend on several factors, including required voltage, rectifier efficiency,
and current efficiency. In addition, from an energy standpoint, electrolytic recovery removes
metals from concentrated solutions more efficiently than from dilute solutions. Electrode
replacement costs may be significant for units using disposable cathodes, especially for high
metal recovery rates. However, if electrodes are constructed properly, cathodes and anodes may
last more than five years for most applications.
Numerous vendors offer electrolytic recovery technology. The technology is
applicable to a wide range of processes, drag-out rinses, and ion-exchange regenerants due to the
diversity of materials and configurations available for anodes and cathodes. Electrolytic recovery
is not applicable to flowing rinses due to the lower metal concentrations and the extended time
required for metal recovery. In most cases, this technology cannot cost-effectively remove
dissolved metals to concentrations required for discharge to POTWs or surface waters.
8.1.2.7 Evaporation
Evaporation is a common chemical recovery technology. There are two basic
types of evaporators: atmospheric and vacuum. Atmospheric evaporators are more prevalent
and are relatively inexpensive to purchase and easy to operate. Vacuum evaporators are
mechanically more sophisticated and are more energy-efficient. Vacuum evaporators are
typically used when evaporation rates greater than 50 to 70 gallons per hour are required. There
are two typical methods of in-process evaporation and reuse: 1) evaporate the water and then
condense the water for reuse in baths and rinses, and 2) evaporate the water and reuse the
concentrate (i.e., the process solution that remains after water is evaporated) in process baths.
Reusing the condensate is more common.
8.1.2.8 Filtration
Filtration removes suspended solids from surface finishing solutions. Suspended
solids in surface finishing solutions may cause roughness and burning of deposits. Filtration uses
various types of equipment, the most common of which are cartridge filters, precoat
diatomaceous earth filters, sand, and multimedia filters. Cartridge filters are available with either
in-tank or external configurations. The in-tank units are used mostly for small tanks and the
external units for larger tanks. Most cartridges are disposable; however, washable and reusable
filters are available, which further reduce waste generation. Precoat, sand, and multimedia filters
are used mostly for large tanks. The filter media used depends on the chemical composition of
the bath. All filtration systems are sized based on solids loading and the required flow rate.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
Membrane filtration can also be used to remove oils and metals from process
baths or rinses. Membrane filters can be used to recycle paint curtain or machine coolant
wastewater and are typically used to recover and recycle electrophoretic painting ("e-coat")
solutions. Membrane filtration is a pressure-driven process used to separate solution components
based on molecular size and shape. Solvent and small solutes can pass through the membrane
while the membrane retains and collects larger compounds as a concentrated waste stream. The
cleaner permeate can be reused in the process. Figure 8-5 shows a typical membrane filtration
unit.
Concentrate
Output
Influent - - - - -
Wastewater
Tubular
Membranes
Figure 8-5. Membrane Filtration Unit
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8.1.2.9
Ion Exchange (in-process)
Ion exchange is a commonly used technology within the MP&M industry. In
addition to water recycling and chemical recovery applications, ion exchange is used to soften or
deionize raw water for process solutions. Figure 8-6 shows a typical ion exchange system.
Ion exchange is a reversible chemical reaction that exchanges ions in a feed
stream for ions of like charge on the surface of an ion-exchange resin. Resins are broadly
divided into cationic or anionic types. Typical cation resins exchange FT for other cations, while
anion resins exchange OH" for other anions.
Influent
Fresh Acid
Regenerant
Pre-fllfer
Fresh Alkaline
Regenerant
Metal-Bearing
Regenerant
Cation
Column
Non-Metal
Bearing
Regenerant
Effluent
Figure 8-6. Ion Exchange
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In practice, a feed stream passes through a column, which holds the resin. The
feed stream is usually either dilute rinse water (in-process ion exchange) or treated wastewater
(end-of-pipe ion exchange). Often, prior to ion-exchange treatment, the feed stream passes
through a cartridge filter and a carbon filter to remove suspended solids and organics that foul the
resin bed. The exchange process continues until the capacity of the resin is reached (i.e., an
exchange has occurred at all the resin sites). A regenerant solution is then passed through the
column. For cation resins, the regenerant is an acid, and the FT ions replace the cations captured
from the feed stream. For anion resins, the regenerant is a base, and OH" ions replace the anions
captured from the feed stream. The metals concentration is much higher in the regenerant than in
the feed stream; therefore, the ion-exchange process not only separates the metals from the
wastestream but also results in a more concentrated wastestream.
Ion exchange is used for water recycling and/or metal recovery. For water
recycling, cation and anion columns are placed in series. The feed stream is deionized and the
product water is reused for rinsing. Often, closed-loop rinsing is achieved. The regenerant from
the cation column contains metal ions, which can be recovered in elemental form via electrolytic
recovery (see Section 8.1.2.6). The anion regenerant is typically discharged to wastewater
treatment. This type of ion exchange is used to recycle relatively dilute rinse streams. Generally,
the total dissolved solids (TDS) concentration of such streams must be below 500 mg/L to
maintain an efficient regeneration frequency. Reducing drag-out can enhance the efficiency of the
recovery process. Effluent TDS concentrations of 2 mg/L or less are typical.
When metal recovery is the only objective, a single or double cation column unit
containing selective resin is used. These resins attract divalent cations while allowing
monovalent cations to pass, a process usually called metal scavenging. This technology is
efficient if the metal ions being scavenged are the primary source of ions in the stream. Ion
exchange provides effective metals recovery even when the metal content of the stream is only a
small fraction of the TDS present in the stream, making scavenging suitable over a wider range
of TDS than water recycling. Scavenging also provides a highly concentrated regenerant,
particularly suitable for electrolytic recovery (see Section 8.1.2.6). Water recycling using this ion
exchange configuration is not possible since only some of the cations and none of the anions are
removed. Standard units typically achieve effluent metal concentrations of under 0.5 mg/L.
Many process wastewaters are excellent candidates for ion exchange, including
the rinse water from plating processes of chromium, copper, cadmium, gold, lead, nickel, tin, tin-
lead, and zinc. Ion exchange resins are usually regenerated using inexpensive chemicals such as
sulfuric acid and sodium hydroxide. Gold-bearing resins are difficult to regenerate and
frequently require incineration to recover the gold content. Lead is also difficult to recover from
ion exchange resins. Methane sulfonic acid and fluoboric acid (usually not suitable for
electrolytic recovery) are effective regenerants for lead ion exchange but are very expensive.
Cyanide rinse waters are amenable to ion exchange; cation resins are capable of breaking the
metal-cyanide complex and the cyanide is removed in the anion column. The metals in the
cation regenerant can be electrolytically recovered and the cyanide present in the anion
regenerant can be returned to the process or discharged to treatment.
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Ion-exchange equipment ranges from small, manual, single-column units to multi-
column, highly automated units. Two sets of columns are necessary for continuous treatment;
one set receives the wastewater flow while the other set is being regenerated. Thus, two-column
metal scavenging and four-column deionizing systems are common. Automatic systems direct
the wastewater flow and initiate regeneration with little or no operator involvement.
The labor requirements for ion exchange depend on the automation level of the
equipment. Manual systems can have significant labor costs associated with preparing,
transporting, and disposing of regenerants. Automatic systems require far less labor. Resins
need to be replaced periodically due to organic contamination, resin oxidation, and fouling from
suspended solids. This process can be hastened by misuse, accidents, or poor engineering.
Equipment size is based on flow rate and concentration. Resin capacity varies but
often ranges from 1 to 2 lbs/ft3. Flow rates may range from 1 to 20 or more gpm. Columns are
typically sized to handle wastewater flow for at least a period of time equal to that required for
regeneration. Automatic systems are sized to provide continuous treatment. Regeneration
volume typically ranges from 2 to 4 resin bed volumes of dilute acid or caustic. Concentrations
of feed stream contaminants generally range from 10 to 20 g/L.
8.1.2.10 Reverse Osmosis
Reverse osmosis is a membrane separation technology used by the MP&M
industry for chemical recovery. Dilute rinse water is pumped to the surface of the reverse
osmosis membrane at pressures of 400 to 1,000 pounds per square inch gauge (psig). The
membrane separates the feed stream into a reject stream and a permeate. The reject stream,
containing most of the dissolved solids in the feed stream, is deflected from the membrane while
the permeate passes through. Reverse osmosis membranes reject more than 99 percent of
multivalent ions and 90 to 96 percent of monovalent ions, in addition to organics and nonionic
dissolved solids. The permeate stream is usually of sufficient quality to be recycled as rinse
water, despite the small percentage of monovalent ions (commonly potassium, sodium and
chloride) that pass through the membrane. Reverse osmosis equipment is similar to the
equipment shown in Figure 8-5.
A sufficiently concentrated reject stream can be returned directly to the process
bath. The reject stream concentration can be increased if the stream is recycled through the unit
more than once or by increasing the feed pressure. In multiple-stage units containing more than
one membrane chamber, the reject stream from the first chamber is routed to the second, and so
on. The combined reject streams from multistage units may, in some cases, have high enough
concentrations to be returned directly to the bath.
The capacity of reverse osmosis equipment is generally measured in flow volume,
and is determined by the membrane surface area and operating pressure. Generally, increasing
the surface area of the membrane increases the capacity. Operating at higher pressures increases
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
the permeate flow volume per unit membrane area (also called the flux). Reject stream
concentration increases with pressure and decreases as flow volume increases.
Facilities may need to prefilter and pretreat the feed stream to lengthen membrane
life or reduce the frequency of fouling; filtration to remove suspended solids is usually necessary.
Adjusting pH may prevent precipitation as the feed stream is concentrated, but it may make the
concentrate unfit to return to the process bath.
Reverse osmosis is most applicable to electroplating rinse waters, including
electroplating of Watts nickel, bright nickel, brass cyanide, copper cyanide, and zinc cyanide.
This technology can treat IDS concentrations of up to 1,000 mg/L. Permeate IDS
concentrations of 250 mg/L or less are typical, and the dissolved solids are mostly common
monovalent ions, allowing the permeate stream to be reused in many rinsing operations.
The maximum achievable reject stream concentration for basic reverse osmosis
equipment is approximately 20,000 mg/L TDS. Multipass and multistage units achieve
concentrations of 30,000 mg/L TDS or higher. If the reject stream is acceptable to return directly
to the process bath and the permeate is recycled as rinse water, a closed loop is created.
However, returning the reject stream directly to the bath is uncommon because the concentration
is often too low. In cases where the reject stream concentration is not high enough to return it to
the bath, it can be concentrated with an evaporator, electrolytically recovered, or treated
conventionally (e.g., with chemical precipitation). When evaporators are used, however, reverse
osmosis loses its low-energy advantage over other in-process reuse and recovery technologies.
When both technologies include an electrolytic recovery unit, reverse osmosis
often has a higher capital cost than ion exchange. As end-of-pipe treatment, reverse osmosis and
ion exchange both remove similar quantities of metals; however, reverse osmosis may allow for
more water recycling. During reverse osmosis, energy is consumed only by pumps. In most
cases, water is recycled; in some cases, a closed loop is possible. Compared to ion exchange,
reverse osmosis can treat somewhat higher feed stream concentrations. The concentration of
reverse osmosis reject streams are near or higher than that of ion-exchange regenerants. Both are
less effective in handling oxidizing chemistries or feed streams high in organics and total
suspended solids (TSS). Ion-exchange effluent generally has a lower TDS concentration than
reverse osmosis permeate and can be recycled in most rinses.
For most applications, reverse osmosis membranes last for one to five years,
although they are susceptible to fouling from organics, suspended solids, or misuse. Reverse
osmosis units may have instrumentation that indicates the condition of the membrane by
measuring the flux. If the membrane fouls or clogs, the flux rate drops, indicating that the
membrane should be cleaned. Labor associated with operating reverse osmosis equipment is for
periodic membrane cleaning. Membrane and pump replacement are the primary maintenance
items.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
8.1.3 Other Types of Pollution Prevention Practices
Many other types of pollution prevention practices are performed at MP&M
facilities including the following: training and supervision; production planning; process or
equipment modification; raw material and product substitution or elimination; loss prevention
and housekeeping; waste segregation and separation; and closed-loop recycling. EPA describes
each of these practices below. Some of these practices may be elements of an Environmental
Management System (EMS).
Training and Supervision. Training and supervision ensure that employees are
aware of, understand, and support the company's pollution prevention goals. Effective training
programs translate these goals into practical information that enables employees to minimize
waste generation by properly and efficiently using tools, supplies, equipment, and materials.
Production Planning. Production planning can minimize the number of process
operation steps and eliminate unnecessary procedures (e.g., planning production can eliminate
additional cleaning steps between process operations).
Process or Equipment Modification. Sites can modify processes and equipment
to minimize the amount of waste generated (e.g., changing rack configuration to reduce drag-
out).
Raw Material and Product Substitution or Elimination Where possible, sites
should replace toxic or hazardous raw materials or products with other materials that produce
less waste and/or less toxic waste (e.g., replacing chromium-bearing solutions with
nonchromium-bearing and less toxic solutions, or consolidating types of cleaning solutions and
machining coolants).
Loss Prevention and Housekeeping. Loss prevention and housekeeping
includes performing preventive maintenance and managing equipment and materials to minimize
leaks, spills, evaporative losses, and other releases (e.g., inspecting the integrity of tanks on a
regular basis; using chemical analyses instead of elapsed time or number of parts processed as
the basis for disposal of a solution).
Waste Segregation and Separation. Sites should avoid mixing different types
of wastes or mixing hazardous wastes with nonhazardous wastes. Similarly, sites should not mix
recyclable materials with noncompatible materials or wastes. For example, MP&M facilities can
segregate scrap metal by metal type, separate cyanide-bearing wastewater for preliminary
treatment, and segregate coolants for recycling or treatment.
Closed-Loop Recycling. MP&M sites can recover and reuse some process
streams. For example, some sites can use ion exchange to recover metal from electroplating
rinse water, the rinsewater can be reused, and the regenerant solution can be used as solution
make-up.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
8.2 Preliminary Treatment of Segregated Wastewater Streams
Preliminary treatment systems reduce pollutant loadings in segregated waste
streams prior to end-of-pipe treatment. Wastewater containing pollutants such as cyanide,
hexavalent chromium, oil and grease, or chelated metals inhibit the performance of end-of-pipe
treatment systems and require preliminary treatment. Proper segregation and treatment of these
streams is critical for the successful treatment of MP&M wastewater. Highly concentrated
metal-bearing wastewater may also be treated to reduce metal concentrations before end-of-pipe
treatment. This section describes the following wastewater streams that typically undergo
preliminary treatment at MP&M facilities:
• Chromium-bearing wastewater;
• Concentrated metal-bearing wastewater;
• Cyanide-bearing wastewater;
• Chelated metal-bearing wastewater; and
• Oil-bearing wastewater.
8.2.1 Chromium-Bearing Wastewater
MP&M facilities generate hexavalent-chromium-bearing wastewater from acid
treatment, anodizing, conversion coating, and electroplating operations and rinses. Hexavalent
chromium exists in an ionic form and does not form a metal hydroxide; therefore, this
wastewater is not treated directly by chemical precipitation and sedimentation. The wastewater
requires preliminary chemical treatment to reduce the hexavalent chromium to trivalent
chromium. The trivalent chromium can then be removed by chemical precipitation and
sedimentation. The chemical reduction process is discussed below. Figure 8-7 presents a
process flow diagram of a continuous chromium reduction system.
Reduction is a chemical reaction in which electrons are transferred from one
chemical (the reducing agent) to the chemical being reduced. Sulfur dioxide, sodium bisulfite,
sodium metabisulfite, and ferrous sulfate form strong reducing agents in water. MP&M facilities
use these reducing agents to reduce hexavalent chromium to the trivalent form, which allows the
metal to be removed from solution by subsequent chemical precipitation.
Sodium metabisulfite, sodium bisulfite, and sulfur dioxide are the most widely
used reducing agents at MP&M sites. Below is an equation showing the sulfur dioxide reaction
(reduction using other reagents is chemically similar):
2H2Cr04 + 3S02 - Cr2(SO4)3 + 2H2O (8-2)
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
Reducing Agent
(Sulfer Dioxide, Sodium Bisulfite,
Sodium Metabisulfite or Ferrous Sulfate}
Hexavalent
Chromium—Bearing
Wastewater from
Unit Operations
Mixer
Reaction
Tank
ORP=250-300 millivolts
pH=2
•Oxidation—Reduction
Potential (ORP) Meter
Trivalent Chromium-
Bearing Wastewater
Outlet (Effluent)
-*• To Chemical Precipitation
and Sedimentation
Figure 8-7. Chemical Reduction of Hexavalent Chromium
An operating pH of between 1 and 3 is normal for chromium reduction. At pH
levels above 5, the reduction rate is slow, and oxidizing agents such as dissolved oxygen and
ferric iron interfere with the reduction process by consuming the reducing agent.
Typically, the chemicals are retained in a reaction tank for 45 minutes. The tank
is equipped with pH and oxidation-reduction potential (ORP) controls. Sulfuric acid is added to
maintain a pH of approximately 2, and a reducing agent is metered to the reaction tank to
maintain the ORP at 250 to 300 millivolts.
Chemical reduction of hexavalent chromium is a proven technology that is widely
used at MP&M sites. Operation at ambient conditions requires little energy, and the process is
well suited to automatic control. For high concentrations of chromium, treatment chemical costs
may be significant.
Maintenance of chemical reduction systems consists of sludge removal, the
frequency of which depends on the concentration of contaminants. There may also be small
amounts of sludge generated due to minor shifts in the solubility of the contaminants (e.g., iron
hydroxides). This sludge can be removed by the sludge-handling equipment associated with the
chemical precipitation system.
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8.2.2 Concentrated Metal-Bearing Wastewater
Concentrated metal-bearing wastewater from spent process solutions can be
slowly metered to the end-of-pipe chemical precipitation system and commingled with other
facility wastewater or batch treated. Some facilities send concentrated metal-bearing wastewater
for off-site treatment rather than treating the wastewater on site. Batch treatment of concentrated
metal-bearing wastewater provides better control of the treatment system (e.g., the treatment
chemicals can be better tailored to the specific solution being treated), better treatment of
difficult-to-treat materials (e.g., photo resist-bearing wastewater), and potential recovery of
metals from the sludge. With batch treatment, effluent from the batch treatment tank is typically
discharged to the end-of-pipe treatment system for additional polishing.
Batch chemical precipitation of concentrated metal-bearing wastewater typically
occurs in a single stirred tank, where a precipitating agent (e.g., sodium hydroxide, lime, sodium
sulfide) is added to create an insoluble metal hydroxide or sulfide complex. Following
precipitate formation, a polyelectrolyte is added to flocculate the metal hydroxide or metal
sulfide particles into larger clumps that will settle to the bottom of the reaction tank following
mixing. Clarified effluent from the batch tank is discharged to the end-of-pipe treatment system
and the settled sludge, typically containing only one type of metal, is transferred offsite for metals
recovery.
8.2.3 Cyanide-Bearing Wastewater
Plating and cleaning wastewater may contain significant amounts of cyanide,
which should be destroyed through preliminary treatment. In addition to its toxicity, cyanide
forms complexes with metals that prohibit subsequent removal in chemical precipitation systems.
Cyanide is typically destroyed using alkaline chlorination with sodium hypochlorite or chlorine
gas or by ozone oxidation. EPA describes these two processes below.
8.2.3.1 Alkaline Chlorination
Cyanide destruction through alkaline chlorination is widely used in industrial
wastewater treatment. Chlorine is typically used as either chlorine gas or sodium hypochlorite
(i.e., bleach). This process is shown by the following two-step chemical reaction:
C12 + NaCN + 2NaOH - NaCNO + 2NaCl + H2O (8-3)
C12 + 4NaOH + 2NaCNO - 2CO2 + N2 + 6NaCl + 2H2O (8-4)
Figure 8-8 presents a process flow diagram showing alkaline chlorination of cyanide.
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
Mixer
iniel (influent) Sodium
Cyanide-Bearmg
YVastewater from
Unit Operations
pH
Meter -
3rTi
^
1
i
3
(9
Reaction
Tank
Cyanide converted to Cyaoate
ORP=350-400 millivolts
pH=10-11
^-^^
1
pH
Potential (ORP) Meter
J Outlet (Effluent) Cyanide-Bearing
ACid
f-~~~H^ '*'f
«"O'
?
^~J
S)
Reaction
Tank
Cyanate converted to Carbon
and Dioxide to Nitrogen
Potential (ORP) Meter
UKP=BetJ millivolts Cj
pH=8-9 I Treated Wastewater to
^*S Wastewater N^v-*-^. — •^ Discharge or to Chemical
^ — ...— "•"-"""'^ Precioitation & Sedimentation
Figure 8-8. Cyanide Destruction Through Alkaline Chlorination
The alkaline chlorination process oxidizes cyanides to carbon dioxide and
nitrogen. The equipment often consists of an equalization tank followed by two continuous
reaction tanks, although the batch reaction can be conducted in a single tank. Each tank has an
electronic controller to monitor and maintain the required pH and ORP. To oxidize cyanides to
cyanates, chlorine or sodium hypochlorite is metered to the reaction tank as necessary to maintain
the ORP at 350 to 400 millivolts, and aqueous sodium hydroxide is added to maintain a pH of 10
to 11. In the second reaction tank, the ORP and the pH level are typically maintained at
600 millivolts and 8 to 9, respectively, to oxidize cyanate to carbon dioxide and nitrogen. Each
reaction tank has a chemical mixer designed to provide approximately one turnover per minute.
The batch process is usually conducted by using two tanks, one to collect water over a specified
time period and one to treat an accumulated batch. If concentrated wastes are frequently
dumped, another tank may be required to equalize the flow to the treatment tank. When the
holding tank is full, the liquid is transferred to the reaction tank for treatment.
Alkaline chlorination can be performed at ambient temperature, can be
automatically controlled at relatively low cost, and can achieve effluent concentrations of free
cyanide that are below the detection limit. Disadvantages include the need for careful pH
control, possible chemical interference in treating mixed wastes, and the potential hazard of
storing and handling chlorine gas (if sodium hypochlorite is not used). If organic compounds are
present, chlorinated organics may be generated. This technology is not effective in treating
metallocyanide complexes, such as ferrocyanide.
8.2.3.2
Ozone Oxidation
A less common cyanide treatment method is ozone oxidation. Ozone, generated
as a gas, is bubbled through a wastewater solution containing free cyanide. Part of the ozone in
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
the gas phase is transferred to the solution, where it reacts with cyanide, converting it to cyanate.
Additional ozone reacts with the cyanate to convert it to nitrogen gas, ammonia, and bicarbonate,
as shown by the reaction below.
O3 ------- >CNO' + O2 (8-5)
3 CNCT + 2O3 + 2OH- + 2H2O ----------- > 3HCO3' + NH3 + N2 + 2O2 (8-6)
The reaction rate is limited by mass transfer of ozone to the liquid, the cyanide
concentration, and temperature. Literature data show that amenable cyanide in electroplating
wastewaters can be reduced to below detection using the oxidation process. Ozone is not
effective in treating metallocyanide complexes, such as ferrocyanide, unless ultraviolet light is
added to the reaction tank.
One advantage ozone has over chlorine is the type of residuals formed. Chlorine
oxidation of organic compounds has the potential to form trihalomethanes. Ozone oxidizes
organic compounds to form relatively less toxic, short-chain organic acids, ketones, and
aldehydes. Equipment required for ozone oxidation of cyanides includes an ozone generator, gas
diffusion system, a mixed reaction tank, and off-gas controls to prevent the release of unreacted
ozone.
The major disadvantage of the ozone oxidation process is the capital and
operating cost. Ozone must be manufactured on site and delivered directly to the reaction tank.
Ozone generation equipment is expensive, and facilities must also purchase closed reaction tanks
and ozone off-gas treatment equipment.
8.2.4 Chelated Metal-Bearing Wastewater
Certain MP&M wastewater contains chelating agents that form metal complexes
and interfere with conventional chemical precipitation processes. This wastewater is often
associated with electroless plating, and requires specific treatment for the chelated metals. In
general, there are three methods of treating these wastewaters:
• Reduction to elemental metal;
• Precipitation as an insoluble compound; and
• Physical separation.
8.2.4.1 Reduction to Elemental Metal
Reduction to elemental metal can be done using one of two methods. One method
is electrolytic recovery (see Section 8.1.2.6), in which the dissolved metal is deposited on a
cathode for reclamation or disposal. The electric current provides the electrons to reduce the
metal ion to its elemental form. The reaction rate and achievable concentration for this
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technology depend on the volume of wastewater per unit surface area of cathode. This method
typically does not lower metal concentrations enough for wastewater discharge.
The second method uses a reducing agent to provide the electrons to reduce the
metal. Possible reducing agents for use in chelated wastewater streams include:
• Sodium borohydride;
• Hydrazine; and
• Sodium hydrosulfite.
Upon reduction, the metal forms a particulate in solution, which can then be
removed by conventional solids removal techniques. To be used effectively these reducing
agents sometimes require the use of other chemicals for pH adjustment. Figure 8-9 presents a
flow diagram showing this method of chemical reduction of chelated metals.
Reducing/Precipitation Agent,
Sodium Borohydride of
Dithiocarbamate
Lime or
inlet (Influent) Sodium
Chelated Metal- """'
Bearing Wastewater
from Unit Operations
PH
Periodic
Batch Sludge -«
Removal
x nyaroxiae
"\ 1 1
dt 1 :;•
.<£
Mixer
g,"
: A!'
Reaction
Tank
Treated
Metal-Bearing
WastnwatHf
it: -».
I Outlet (Effluent)
*~To Chemical Precipitation
and Sedimentation
8.2.4.2
Figure 8-9. Chemical Reduction / Precipitation of Chelated Metals
Precipitation of an Insoluble Compound
The presence of chelating agents hinders the formation of hydroxides, making
hydroxide precipitation ineffective on chelated metal-bearing wastewaters. Other precipitation
methods that are less affected by chelating agents include sulfide precipitation, dithiocarbamate
(DTC) precipitation, and carbonate precipitation. Except for DTC precipitation, all of these
technologies are discussed in Section 8.3. DTC is added to solution in stoichiometric ratio to the
metals present. DTC is effective in treating chelated wastewater; however, DTC compounds are
also a class of pesticides and, if used incorrectly, may cause process upsets in the biological
treatment used at a POTW and can potentially be harmful to the environment (e.g., lead to fish
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kills if DTC passes through the POTW and reaches surface waters). In addition to DTC's
potential toxic effects when misused, another disadvantage is DTC precipitation generates large
amounts of sludge.
8.2.4.3 Physical Separation
Ion exchange and reverse osmosis can separate metals from solution. These
technologies are not affected by chelating agents in the wastewater, making them effective in
treating wastewater from electroless plating. These technologies are discussed in section 8.1.2.9
and 8.1.2.10, respectively.
8.2.5 Oil-Bearing Wastewater
Some MP&M wastewater (e.g., alkaline cleaning wastewater and water-based
metal-working fluids) contains significant amounts of oil and grease. This wastewater
sometimes requires preliminary treatment to remove oil and grease and organic pollutants.
Oil/water separation includes the breaking of oil/water emulsions as well as the gravity
separation of oil. When only free oil (i.e., non-emulsified oil) is present, only oil skimming is
necessary for effective treatment. Techniques available to remove oil include chemical emulsion
breaking followed by oil/water separation or dissolved air flotation, oil skimming, and
ultrafiltration. EPA describes these technologies in more detail below.
8.2.5.1 Chemical Emulsion Breaking
Chemical emulsion breaking is used to break stable oil/water emulsions (oil
dispersed in water, stabilized by electrical charges and emulsifying agents). A stable emulsion
will not separate or break down without chemical and or physical treatment. Chemical emulsion
breaking is applicable to wastewater containing emulsified coolants and lubricants such as
machining and grinding coolants and impact and pressure deformation lubricants. This
technology is also applicable to cleaning solutions that contain emulsified oils. Figure 8-10
shows a flow diagram of a type of continuous chemical emulsion breaking system.
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chemical addition
iA0m (polymer, alum, ferric chloride)
Figure 8-10. Continuous Chemical Emulsion Breaking Unit with Coalescing Plates
Treatment of spent oil/water emulsions involves adding chemicals to break the
emulsion followed by oil/water separation. The major equipment required for chemical emulsion
breaking includes reaction chambers with agitators, chemical storage tanks, chemical feed
systems, pumps, and piping. Factors to be considered for destroying emulsions are type of
chemicals, dosage and sequence of addition, pH, mixing, heating requirements, and retention
time.
Chemicals (e.g., polymers, alum, ferric chloride, and organic emulsion breakers)
break emulsions by neutralizing repulsive charges between particles, precipitating or salting out
emulsifying agents, or weakening the interfacial film between the oil and water so it is readily
broken. Reactive cations (e.g., FT, Al+3, Fe+3) and cationic polymers are particularly effective in
breaking dilute oil/water emulsions. Once the charges have been neutralized or the interfacial
film broken, the small oil droplets and suspended solids either adsorb on the surface of the floe
that is formed, or break out and float to the top. Different types of emulsion-breaking chemicals
are used for different types of oils. If more than one chemical is required, the sequence of adding
the chemicals can affect both breaking efficiency and chemical dosages.
Another important consideration in emulsion breaking is pH, especially if cationic
inorganic chemicals, such as alum, are used as coagulants. For example, a pH of between 2 and
4 keeps the aluminum ion in its most positive state where it most effectively neutralizes charges.
After some of the oil is broken free and skimmed, raising the pH into the 6-to-8 range with lime
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or caustic causes the aluminum to hydrolyze and precipitate as aluminum hydroxide. This floe
entraps or adsorbs destabilized oil droplets, which can then be separated from the water.
Cationic polymers can break emulsions over a wider pH range and thus avoid acid corrosion and
the additional sludge generated from neutralization; however, this process usually requires
adding an inorganic flocculent to supplement the adsorptive properties of the polymer emulsion
breaker.
Mixing is important in effectively breaking oil/water emulsions because it
provides proper chemical feed and dispersion. Mixing also causes droplets to collide and break
the emulsion and promotes subsequent agglomeration into larger droplets. Heating also
improves chemical emulsion breaking by lowering the viscosity and increasing the apparent
specific gravity differential between oil and water. In addition, heating increases the frequency
of droplet collisions, which helps to rupture the interfacial film.
Once an emulsion is broken, the oil floats to the surface of the water because of
the difference in specific gravities between the oil and the water. Solids usually form a layer
between the oil and water, since some solids become suspended in the oil. The longer the
retention time, the more complete the separation between the oil, solids, and water. Oils and
solids are typically skimmed from the surface of the water in a subsequent step after chemical
emulsion breaking. Often, other techniques, such as air flotation or rotational separation (e.g.,
centrifugation), are used to enhance separation after chemical emulsion breaking.
The advantages of chemical emulsion breaking are the high removal efficiency
potential and the possibility of reclaiming the oily waste. Disadvantages include corrosion
problems associated with acid-alum systems, operator training requirements for batch treatment,
chemical sludges produced, and poor efficiency for low oil concentrations.
Chemical emulsion breaking is a very reliable process. The main control
parameters are pH and temperature. Maintenance is required on pumps, mixers, instrumentation
and valves, and periodic cleaning of the treatment tank is required to remove any accumulated
solids. Energy use is typically limited to mixers and pumps, but can also include heating. Solid
wastes generated by chemical emulsion breaking include surface oil and oily sludge, which are
usually contract hauled for disposal by a licensed contractor. If the recovered oil contains a low
enough percentage of water, it may be burned for its fuel value or processed and reused.
8.2.5.2 Oil Skimming
Oil skimming is a physical separation technology that removes free or floating oil
from wastewater using the difference in specific gravity between oils and water. Common
separation devices include belts, rotating drums, disks, and weir oil skimmers and coalescers.
These devices are not suited to remove emulsified oil, which requires chemical treatment,
membrane filtration, or other treatment. Figures 8-1 la and 8-1 Ib show flow diagrams of disc
and belt oil skimming units, respectively, that can be used for small systems or on process tanks.
The oil removal system shown in Figure 8-10 is used for large systems.
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To separate oil from process solutions, oil skimming devices are typically
mounted onto the side of a tank and operated on a continuous basis. The disk skimmer is a
vertically rotating disk that is partially submerged in the solution (see Figure 8-1 la). The disk
continuously revolves between spring-loaded wiper blades that are located above the liquid
surface. The disk's adhesive characteristics cause the floating oil to remain on the disk. As the
disk's surface passes under the wiper blades, the oil is scraped off and diverted to a run-off spout
Disc Movement
Figure 8-1 la. Disc
Oil Skimming Unit
for collection. Belt (see figure 8-1 Ib) and drum skimmers operate in a similar manner, with
either a continuous belt or drum rotating partially submerged in a tank. As the surface of the belt
or drum emerges from the liquid, the oil that adheres to the surface is scraped off (drum) or
squeezed off (belt) and diverted to a collection vessel. The oil is typically contract hauled for
disposal.
Gravity separators use overflow and underflow weirs to skim a floating oil layer
from the surface of the wastewater. A weir allows the oil layer to flow over the weir into a
trough for disposal or reuse while most of the water flows underneath the weir. A diffusion
device, such as a vertical slot weir, helps create a uniform flow through the system and increase
oil removal efficiency.
A skimmer's removal efficiency depends on the composition of the waste stream
and the retention time of the water in the tank. Larger, more buoyant particles require less
retention time than smaller particles. The retention time necessary for phase separation and
subsequent skimming varies from 1 to 15 minutes, depending on the wastewater characteristics.
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Gravity-type separators tend to be more effective for wastewater streams with
consistently large amounts of surface oil. Drum and belt type skimmers are more applicable to
waste streams containing smaller amounts of floating oil. A gravity separator in conjunction
with a drum-type skimmer effectively removes floating contaminants from nonemulsified oily
waste streams.
Belt
Movement
Figure 8-1 lb.
Belt Oil Skimming Unit
Coalescers remove oil droplets too finely dispersed for conventional gravity
separation-skimming technology. Coalescing also reduces the residence times (and therefore
separator volumes) required to separate oil from some wastes. The basic principle of coalescence
involves the attraction of oil droplets to the coalescing medium (typically plates). The oil
droplets accumulate on the medium and then rise to the surface of the solution as they combine to
form larger particles. The most important requirements for coalescing media are attraction for oil
and large surface area. Coalescing media include polypropylene, ceramic, and glass.
Coalescing stages may be integrated with a wide variety of gravity oil separators,
and some systems may incorporate several coalescing stages. A preliminary oil skimming step
avoids overloading the coalescer.
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Oil separation not only removes oil but also removes organics that are more
soluble in oil than in water. Subsequent clarification removes organic solids directly and
probably removes dissolved organics by adsorption on inorganic solids. In MP&M operations,
sources of these organics are mainly process coolants and lubricants, additives to formulations of
cleaners, paint formulations, or leaching from plastic lines and other materials.
8.2.5.3 Flotation of Oils or Solids
Air flotation combined with chemical emulsion breaking is an effective way of
treating oily wastewater containing low concentrations of metals. Flotation is used to separate oil
and grease from the wastewater, and small amounts of metal will be removed by entrainment or
adsorption. In dissolved air flotation (DAF), air is injected into a fluid under pressure. The
amount of air that can dissolve in a fluid increases with increasing pressure. When the pressure
is released, the air comes out of solution as bubbles, which attach to oil and grease molecules and
"float" the oil and grease to the surface. Induced-air flotation uses the same separation principles
as DAF systems but the gas is self-induced by a rotor-disperser mechanism.
Figure 8-12 shows a diagram of a DAF unit. A DAF system consists of a
pressurizing pump, air injection equipment, pressurizing tank, a pressure release valve, and a
flotation tank. DAF systems operate in two modes: full-flow pressurization and recycle
pressurization. In full-flow pressurization, all influent wastewater is pressurized and injected
with air. The wastewater then enters the flotation unit where the pressure is relieved and bubbles
form, causing the oil and grease to rise to the surface with the air bubbles. In recycle
pressurization, part of the clarified effluent is recycled back to the influent of the dissolved air
flotation unit, then pressurized and supersaturated with air. The recycled effluent then flows
through a pressure release valve into the flotation unit. Pressurizing only the recycle reduces the
amount of energy required to pressurize the entire influent. DAF is the most common method of
air flotation.
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air injection
sludge
(to dewatering)
-*" wastewater flow
su ge ow
Figure 8-12. Dissolved Air Flotation Unit
8.2.5.4
Ultrafiltration
Ultrafiltration is a membrane-based process used to separate solution components
based on molecular size and shape. Using an applied pressure difference across a membrane,
solvent and small solute species pass through the membrane and are collected as permeate while
the membrane retains larger compounds, which are recovered as concentrate. Figure 8-5 shows a
typical membrane filtration unit.
Ultrafiltration typically removes materials ranging from 0.002 to 0.2 microns or
molecular-weights from 500 to 300,000. It can be used for the treatment of oily wastewater.
Prefiltration of the Ultrafiltration influent removes large particles and free oil to prevent
membrane damage and fouling. Most Ultrafiltration membranes are made of homogeneous
polymer or copolymer material. The transmembrane pressure required for Ultrafiltration depends
on membrane pore size, and typically ranges between 15 to 200 psi.
Ultrafiltration typically produces a concentrated oil phase that is 2 to 5 percent of
the influent volume. Oily concentrates are typically contract hauled or incinerated, and the
permeate (water phase) can either be treated further to remove water-soluble metals and organics,
or be discharged, depending on local and state requirements.
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An ultrafiltration system includes: pumps and feed vessels, piping or tubing,
monitoring and control units for temperature, pressure, and flow rate; process and cleaning tanks;
and membranes. Membranes are specifically designed to handle various waste stream
parameters, including temperature, pH, and chemical compatibility. Different types of
membranes can be purchased, including hollow fiber, tubular, flat plate, and spiral wound. The
type selected depends on the type of application. For example, tubular membranes are
commonly used to separate suspended solids, whereas spiral wound membranes are used to
separate oil from water. Ultrafiltration designed for oil removal is typically more expensive than
dissolved air flotation systems. In terms of maintenance, membranes must be cleaned
periodically to ensure effective treatment.
8.3 End-of-Pipe Wastewater and Sludge Treatment Technologies
This section describes end-of-pipe technologies that MP&M facilities can use for
wastewater and sludge treatment. Section 8.3.1 discusses metal removal technologies, Section
8.3.2 discusses oil removal technologies, Section 8.3.3 discusses polishing technologies, and
Section 8.3.4 discusses sludge-handling technologies.
8.3.1 Metals Removal
The most common end-of-pipe treatment technology used in the MP&M industry
to remove dissolved metals is chemical precipitation and flocculation followed by gravity
clarification. Microfiltration can be used in place of clarification. The types of equipment used
for chemical precipitation vary widely. Small batch operations can be performed in a single tank
that typically has a conical bottom to permit removal of settled solids. Continuous processes are
usually performed in a series of tanks, including an equalization tank, a rapid-mix tank for
dispersing the precipitating chemicals, and a slow-mix tank for adding coagulants and flocculants
and for floe formation.
For continuous-flow systems, the first tank in the treatment train is typically the
equalization tank. In the chemical precipitation system, the flow equalization tank prevents
upsets in processing operations from exceeding the hydraulic design capacity of the treatment
system, improves chemical feed control, and provides an opportunity for wastewater
neutralization.
Commingled wastewater from the equalization tank enters the rapid mix tank,
where various types of precipitation chemicals are added to convert the soluble metals into
insoluble compounds. Following precipitation, the wastewater flows into a flocculation tank
where polyelectrolytes (polymers) are added, causing the precipitated solids to coagulate into
larger particles that can be removed by gravity settling or microfiltration.
Chemical precipitation is a highly reliable technology when proper monitoring
and control are used. The effectiveness of metal precipitation processes depends on the types of
equipment used and numerous operating factors, such as the characteristics of the raw
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wastewater, types of treatment reagents used, and operating pH. In some cases, operational
factors need to be optimized to achieve sufficiently low effluent concentrations. Often, subtle
changes such as varying the pH, altering chemical dosage, or extending the process reaction time
may sufficiently improve its efficiency. In other cases, modifications to the treatment system are
necessary. For example, some raw wastewater contains chemicals that may interfere with the
precipitation of metals, which may require additional treatment reagents such as ferrous sulfate,
sodium hydrosulfate, aluminum sulfate, or calcium chloride. These chemicals may be added
prior to or during the precipitation process.
Chemical precipitation systems require routine maintenance for proper operation.
Routine maintenance includes: calibrating instrumentation and cleaning probes; maintaining
chemical pumps and mixers (inspection, cleaning, lubrication, replacing seals and packing,
replacing check valves, cleaning strainers); and monitoring tanks and sumps (inspection,
cleaning, corrosion prevention). There are several basic methods of performing chemical
precipitation and flocculation and many variations of each method. The four most common
methods are described below. Figure 8-13 shows a typical continuous chemical precipitation
system.
Hydroxide Precipitation. Hydroxide precipitation is the most common method
of removing metals from MP&M wastewater. This process is typically performed in several
stages. In an initial tank, which is mechanically agitated, alkaline treatment reagents such as lime
(calcium hydroxide or hydrated lime), sodium hydroxide, or magnesium hydroxide are added to
the wastewater to precipitate metal ions as metal hydroxides. The reaction for precipitation of a
divalent metal using lime is shown in the following equation:
M2+ + Ca(OH)2 - M(OH)2 + Ca2+ (8-7)
The precipitation process is usually operated at a pH of between 8.5 and 10.0, depending on the
types of metals in the wastewater. The pH set point is selected by choosing the value at which
metals are most effectively removed. Figure 8-14 shows the effect of pH on hydroxide
precipitation. As shown in this figure, most metal hydroxides have an optimum pH (i.e., a
minimum solubility point) at which the metal is most effectively precipitated.
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chemical
addition
Figure 8-13. Continuous Chemical Precipitation System with Lamella Clarifier
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
IP 11 I2 U
Figure 8-14. Effect of pH on Hydroxide and Sulfide Precipitation
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After precipitation, the metal hydroxide particles are very fine and resistant to
settling. To increase particle size and improve the settling characteristics of the metal
hydroxides, coagulating and flocculating agents are added, usually in a second tank, and slowly
mixed. Coagulating and flocculating agents include inorganic chemicals such as alum and
ferrous sulfate, and a highly diverse range of organic poly electrolytes with varying characteristics
suitable for different wastewaters. The particles are then settled in a separate clarification tank
(e.g., a lamella clarifier), under quiescent conditions, using the difference in density between the
solid particles and the wastewater. The solids are removed from the bottom of the settling tank
or clarifier, then transferred to a thickener or other dewatering process (see Section 8.3.4). The
effluent is either further processed in a polishing unit or discharged.
Sulfide Precipitation. The sulfide precipitation process uses equipment similar
to that used for hydroxide precipitation. The major difference between the two processes is the
treatment reagents used. Sulfide precipitation uses either soluble sulfides (e.g., hydrogen sulfide
or sodium sulfide) or insoluble sulfides (e.g., ferrous sulfide) in place of alkali reagents used in
hydroxide precipitation. The sulfide reagents precipitate dissolved metals as metal sulfides,
which often have lower solubility limits than metal hydroxides. Therefore, the sulfide
precipitation process can (for many metals) reduce the levels of residual dissolved metal in the
treated effluent (see Figure 8-14). The sulfide precipitation reaction is shown in the following
equation:
M2+ + FeS - MS + Fe2+ (8-8)
Unlike hydroxides, sulfide can precipitate most chelated metals and can remove hexavalent
chromium without first reducing the chromium to its trivalent state.
The major disadvantages of sulfide precipitation as compared to hydroxide precipitation are
higher capital and operating costs and larger sludge generation rates due to the precipitation of
ferrous ions. Additional disadvantages of sulfide precipitation are the potential for toxic
hydrogen sulfide gas generation, the potential for excessive sulfide releases in the effluent, and
the generation of sulfide odors.
Carbonate Precipitation. Carbonate precipitation typically uses sodium
carbonate (soda ash), sodium bicarbonate, or calcium carbonate to form insoluble metal
carbonates. The reaction is shown in the following equation:
M2+ + N^CC^ - MCO3 + 2Na+ (8-9)
Carbonate precipitation is similar in operation to hydroxide precipitation, and is
typically performed to remove metals such as cadmium or lead. For these metals, carbonate
precipitation operates at a lower pH to achieve effluent concentrations similar to those achieved
by hydroxide precipitation. Carbonate precipitation and hydroxide precipitation are sometimes
performed in conjunction, which may improve the overall performance of certain systems.
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Carbonate precipitation is less popular than hydroxide precipitation due to the
higher cost of treatment reagents and certain operational problems, such as the release of carbon
dioxide gas, which can result in foaming and/or floating sludge. Also, since many metal
carbonates are more soluble than sulfides or hydroxides, this process is not effective for all
metals.
Sodium Borohydride Precipitation. Sodium borohydride precipitation uses
sodium borohydride as a reducing agent to precipitate metals from solution as insoluble
elemental metals. This reaction is shown in the following equations:
4M2+ + NaBH4 + 2H2O - NaBO2 + 4M + 8H+ (8-10)
4M2+ + NaBH4 + 8OFT - NaBO2 + 4M + 6H2O (8-11)
This process is similar in operation to hydroxide precipitation. Borohydride
precipitation is usually performed in a pH range of 8 to 11 to efficiently utilize borohydride. The
optimum pH is determined by testing borohydride usage, reaction time, and effluent quality.
Sodium borohydride precipitation effectively removes lead, mercury, nickel,
copper, cadmium, and precious metals, such as gold, silver, and platinum, from wastewater. This
process has also been reported to reduce sludge generation by 50 percent over traditional
precipitation. However, sodium borohydride precipitation is much more expensive than other
precipitation methods.
8.3.1.1 Gravity Clarification for Solids Removal
Gravity sedimentation to remove precipitated metal hydroxides is the most
common method of clarification (solids removal) used in MP&M facilities. Typically, two types
of sedimentation devices are used: inclined-plate (e.g., lamella) clarifiers and circular clarifiers.
Figure 8-15 shows a circular clarifier. The continuous chemical precipitation shown in Figure 8-
13 uses a lamella clarifier. Lamella clarifiers often provide superior clarification and are more
common at MP&M facilities due to the smaller area required when compared to circular
clarifiers. Lamella clarifiers typically require 65 to 80 percent of the area required for a circular
clarifier. Their design promotes laminar flow through the clarifier, even when the water
throughput is relatively high. Lamella clarifiers permit overflow rates at least two to four times
greater than conventional clarifiers.
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Operating Platform
Feed Well
Surface
Skimmer
8-39
Scum Trough
Scum
Pit
Sludge Rake
Center Cage
Sludge Pipe
Overflow Weir
Clarified Effluent
Channel
Influent Pipe
Figure 8-15. Clarifier
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
Lamella clarifiers contain inclined plates oriented at angles varying between 45
and 60 degrees from horizontal. As the water rises through the plates, the solids settle on the
lower side of the plate. The clarified effluent continues up through the plate, passes over a weir,
and is collected in an effluent holding tank. The solids collect on the lower side of the plate and
slide downward due to the inclination of the plate. The solids collect on the bottom of the
clarifier and are scraped into a sludge hopper before discharge to the thickener.
Overflow rates for lamella clarifiers vary from 1,000 to 1,500 gpd/ft2 for metal
hydroxide sludges, assuming the flow is uniformly distributed through the plate settlers. Clarifier
inlets must be designed to distribute flow uniformly through the tank and plate settlers. In
addition, since solids can build up on plate surfaces, the clarifier should be cleaned periodically.
Otherwise, solids may become dislodged from the plates, and degrade effluent quality, and
nonuniform buildup may adversely affect flow distribution through the plates.
8.3.1.2 Microfiltration for Solids Removal
Microfiltration can be used as an alternative to conventional gravity clarification
after chemical precipitation. Microfiltration is a membrane-based process used to separate small
suspended particles based on size and shape. Using an applied pressure difference across a
membrane, water and small solute species pass through the membrane and are collected as
permeate while larger particles such as precipitated and flocculated metal hydroxides are retained
by the membrane and are recovered as concentrate. Microfiltration is similar to ultrafiltration
(Section 8.2.5.4) but has a larger pore size.
Microfiltration removes materials ranging from 0.1 to 1.0 microns (e.g., colloidal
particles, heavy metal particulates and their hydroxides). Most microfiltration membranes are
made of homogeneous polymer material. The transmembrane pressure required for
microfiltration typically ranges between 3 to 50 psi, depending on membrane pore size.
Microfiltration produces a concentrated suspended solid slurry that is typically
discharged to dewatering equipment such as a sludge thickener and a filter press. The permeate
can either be treated further to adjust the pH or be discharged, depending on local and state
requirements. Figure 8-5 shows a typical membrane filtration system.
The microfiltration system includes: pumps and feed vessels; piping or tubing;
monitoring and control units for temperature, pressure, and flow rate; process and cleaning tanks;
and membranes. Membranes are specifically designed to handle various waste stream
parameters, including temperature, pH, and chemical compatibility. Different types of
membranes can be purchased, including hollow fiber, tubular, flat plate, and spiral wound. The
configuration selected for a particular facility depends on the type of application. For example,
tubular membranes are commonly used to separate suspended solids, whereas spiral wound
membranes are used to separate oils from water. Microfiltration is more expensive than
conventional gravity clarification. Membranes must be periodically cleaned to prevent fouling
and ensure effective treatment.
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8.3.2 Oil Removal
Operations such as machining and grinding, disassembly of oily equipment, and
cleaning can generate wastewater containing organic machining coolants, hydraulic oils, and
lubricating oils. In addition, shipbuilding facilities may commingle their oily bilge water with
other shore-side operations, resulting in a mixed oily wastewater. Data collected during MP&M
site visits, sampling episodes, and from the MP&M detailed surveys showed a variety of methods
to treat oily wastewater. The primary treatment technologies are emulsion breaking and gravity
flotation, emulsion breaking and dissolved air flotation, and ultrafiltration. EPA discussed these
technologies in the preliminary treatment section (see Section 8.2.5).
8.3.3 Polishing Technologies
Polishing systems remove small amounts of pollutants that may remain in the
effluent after treatment by technologies such as chemical precipitation and clarification and
ultrafiltration. These systems can also act as a temporary measure to prevent pollutant discharge
should the primary treatment technology fail due to a process upset or catastrophic event. The
following is a description of end-of-pipe polishing technologies that are applicable to MP&M
facilities.
8.3.3.1 Multimedia Filtration
Multimedia filtration systems are typically used to remove small amounts of
suspended solids (metal precipitates) entrained in effluent from gravity clarifiers. Multimedia
polishing filters are typically designed to remove 90 percent or greater of all filterable suspended
solids 20 microns or larger at a maximum influent concentration of 40 mg/L. Wastewater is
pumped from a holding tank through the filter. The principal design factor for the multimedia
filter is the hydraulic loading. Typical hydraulic loadings range between 4 and 5 gpm/ft2.
Multimedia filters are cleaned by backwashing with clean water. Backwashing is timed to
prevent breakthrough of the suspended solids into the effluent. Figure 8-16 shows a diagram of a
multimedia filtration system.
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Influent
Effluent
Figure 8-16. Multimedia Filtration System
8.3.3.2
Activated Carbon Adsorption
Activated carbon adsorption removes dissolved organic compounds from
wastewater streams. For some MP&M facilities, carbon adsorption is used to polish effluent
from ultrafiltration systems treating oily wastewater. During adsorption, molecules of a
dissolved compound adhere to the surface of an adsorbent solid. Activated carbon is an excellent
adsorption medium due to its large internal surface area, generally high attraction to organic
pollutants, and hydrophobic nature (i.e., water will not occupy bonding sites and interfere with
the adsorption of pollutants). Pollutants in the wastewater bond on the activated carbon grains
until all the surface bonding sites are occupied. At that point, the carbon is considered to be
"spent." Spent carbon requires regeneration, which results in reduced adsorption capacity
compared to fresh carbon. After several regenerations, the carbon is disposed.
The carbon is placed in granular carbon system vessels, forming a "filter" bed.
Vessels are usually circular for pressure systems or rectangular for gravity flow systems. For
wastewater treatment, activated carbon is typically packed into one or more filter beds or
columns; a typical treatment system consists of multiple filter beds in series. Wastewater flows
through the filter beds and is allowed to come in contact with all portions of the activated carbon.
The activated carbon in the upper portion of the column is spent first (assuming flow is
downward), and progressively lower regions of the column are spent as the adsorption zone
moves down the unit. When pollutant concentrations at the bottom of the column begin to
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increase above acceptable levels, the entire column is considered spent and must be regenerated
or removed.
8.3.3.3 Reverse Osmosis
Reverse osmosis is a membrane separation technology used by the MP&M
industry as an in-process step or as an end-of-pipe treatment. Section 8.2 discusses in-process
reverse osmosis. In an end-of-pipe application, reverse osmosis is typically performed to recycle
water and reduce discharge volume rather than recover chemicals. The effluent from a
conventional treatment system generally has a TDS concentration unacceptable for most rinsing
operations, and cannot be recycled. TDS concentrations can be reduced by reverse osmosis
membranes with or without some pretreatment, and the resulting effluent stream can be used for
most rinsing operations.
8.3.3.4 Ion Exchange
Ion exchange is used for both in-process and end-of-pipe applications. Section
8.2 discusses in-process ion exchange. Ion exchange may also be used as an end-of-pipe final
polishing step, or to recycle water. This technology generally uses cation resins to remove metals
but sometimes both cation and anion columns are used. The regenerant from end-of-pipe ion
exchange is not usually amenable to metals recovery as it typically contains multiple metals at
low concentrations.
8.3.4 Sludge Handling
EPA discusses the following sludge-handling technologies in this section.
• Gravity thickening;
• Pressure filtration;
• Sludge drying; and
• Vacuum filtration.
8.3.4.1 Gravity Thickening
Gravity thickening is a physical liquid-solid separation technology used to
dewater wastewater treatment sludge. Sludge is fed from a primary settling tank or clarifier to a
thickening tank, where gravity separates the supernatant (liquid) from the sludge, increasing the
sludge density. The supernatant is returned to the primary settling tank or the head of the
treatment system for further treatment. The thickened sludge that collects on the bottom of the
tank is pumped to additional dewatering equipment or contract hauled for disposal. Figure 8-17
shows a diagram of a gravity thickener.
Gravity thickeners are generally used in facilities where the sludge is to be further
dewatered by a mechanical device, such as a filter press. Increasing the solids content in the
8-43
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
thickener substantially reduces capital and operating costs of the subsequent dewatering device
and also reduces the hauling cost. This process is potentially applicable to any MP&M site that
generates sludge.
Sludge from
Chemical Precipitation
(approx. 3% solids)
Supernatant Back
to Chemical Precipitation
Thickened Sludge to
Contract Haul or to
Sludge Dewatering
{approx. 5% solids)
Figure 8-17. Gravity Thickening
8.3.4.2
Pressure Filtration
The filter press is the most common type of pressure filtration used in the MP&M
industry for dewatering wastewater treatment sludges. A filter press consists of a series of
parallel plates pressed together by a hydraulic ram (older models may have a hand crank), with
cavities between the plates. Figure 8-18 shows a diagram of a plate-and-frame filter press. The
filter press plates are concave on each side to form cavities and are covered with a filter cloth. At
the start of a cycle, a hydraulic pump clamps the plates tightly together and a feed pump forces a
sludge slurry into the cavities of the plates. The liquid (filtrate) escapes through the filter cloth
and grooves molded into the plates and is forced by the pressure of the feed pump (typically
around 100 psi) to a discharge port. The solids are retained by the cloth and remain in the
cavities. This process continues until the cavities are packed with sludge solids. An air blow-
down manifold is used on some units at the end of the filtration cycle to drain remaining liquid
from the system, further drying the sludge. The pressure is then released and the plates are
separated. The sludge solids or cake is loosened from the cavities and falls into a hopper or
drum. A plate filter press can produce a sludge cake with a dryness of approximately 25 to 40
8-44
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
percent solids for metal hydroxides precipitated with sodium hydroxide, and 35 to 60 percent
solids for metal hydroxides precipitated with calcium hydroxide. The final solids content
depends on the length of the drying cycle. Filter presses are available in a very wide range of
capacities (0.6 ft3 to 20 ft3). A typical operating cycle is from 4 to 8 hours, depending on the
dewatering characteristics of the sludge. Units are usually sized based on one or two cycles per
day.
plates
and
frames
filtrate
flow
out
dewatered
sludge (cake)
unloaded
Figure 8-18. Plate-and-Frame Filter Press
8.3.4.3
Vacuum Filtration
Vacuum filtration is performed at some MP&M sites to reduce the water content
of sludge, increasing the solids content from approximately 5 percent to between 20 and
30 percent. These MP&M sites generally use cylindrical drum vacuum filters. The filters on
these drums are typically either made of natural or synthetic fibers or a wire-mesh fabric. The
drum is dipped into a vat of sludge and rotates slowly. A vacuum inside the drum draws sludge
to the filter. Water is drawn through the filter to a discharge port, and the dewatered sludge is
scraped from the filter. Because dewatering sludge with a vacuum filter is relatively expensive
per kilogram of water removed, the liquid sludge is frequently gravity-thickened prior to vacuum
filtration. Figure 8-19 shows a typical vacuum filter. Vacuum filters are frequently used both in
8-45
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
municipal treatment plants and in a wide variety of industries. They are most commonly used in
larger facilities, which may have a thickener to double the solids content of clarifier sludge
before vacuum filtering. Often a precoat is used to inhibit filter binding.
scraper
> filtrate
Figure 8-19. Rotary Vacuum Filter
Maintenance of vacuum filters involves cleaning or replacing the filter media,
drainage grids, drainage piping, filter parts, and other parts. Since maintenance time may be as
high as 20 percent of total operating time, facilities may maintain one or more spare units. If this
technology is used intermittently, the facility may drain and wash the filter equipment each time
it is taken out of service.
8-46
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8.0 - Pollution Prevention Practices and Wastewater Treatment Technologies
8.3.4.4 Sludge Drying
Wastewater treatment sludges are often hauled long distances to disposal sites.
The transportation and disposal costs depend mostly on the volume of sludge, which is directly
related to its water content. Therefore, many MP&M sites use sludge drying equipment
following dewatering or vacuum filtration to further reduce the volume of the sludge. The solids
content of the sludge dewatered on a filter press usually ranges from 25 to 60 percent. Drying
equipment can produce a waste material with a solids content of approximately 90 percent.
There are several design variations for sludge drying equipment. A commonly
used system consists of an auger or conveyor system to move a thin layer of sludge through a
drying region and discharge it into a hopper. Various heat sources including electric, electric
infrared, steam, and gas are used for sludge drying. Some continuous units are designed such
that the sludge cake discharged from a filter press drops into the feed hopper of the unit, making
the overall dewatering process more automated. System capacities range from less than 1 ft3/hr
to more than 20 ft3/hr of feed. Sludge drying equipment requires an air exhaust system due to the
fumes generated during drying.
8.4 References
1. U.S. Environmental Protection Agency. Facility Pollution Prevention Guide.
EPA-600-92-088, Washington, DC. 1992.
2. U.S. Environmental Protection Agency. Development Document for Effluent
Limitations Guidelines and Standards for the Nonferrous Metals Forming and
Metal Powders Point Source Category. EPA 440-1-86-019, September, 1996.
3. Cherry, K.F. Plating Waste Treatment. Ann Arbor Sciences Publishers, Inc., Ann
Arbor, Michigan, 1982.
4. Freeman, H.M. Standard Handbook of Hazardous Waste Treatment and Disposal.
McGraw Hill Book Company, New York, 1989.
5. Cushnie. George C.. Pollution Prevention and Control Technology for Plating
Operations. National Center for Manufacturing Sciences, 1994.
6. Eckenfelder, W. Wesley. Industrial Water Pollution Control. McGrawHill, 2000.
7. Letterman, Raymond D., Water Quality and Treatment: A Handbook of
Community Water Supplies. Fifth Edition, Mc-Graw Hill, 1999.
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9.0 - Technology Options
9.0 TECHNOLOGY OPTIONS
This section describes the technology options that EPA used in developing the Metal
Products and Machinery (MP&M) effluent limitations guidelines and standards. EPA developed these
options based on the technologies described in Section 8.0. Section 9.1 summarizes the methodology
EPA used to select the technologies included in the options. Section 9.2 describes the technology
options in detail The Agency selected the technologies included in each option for
development of the MP&M effluent limitations guidelines and standards. EPA does not
require sites to implement these specific technologies to comply with the MP&M effluent
guidelines; sites can install any technology (or completely eliminate their discharge through
contract hauling or recycling as long as they achieve the final effluent limitations. EPA used
these technology options to estimate pollutant loadings and reductions (Section 12.0) and compliance
costs (Section 11.0) and to develop the MP&M effluent limitations guidelines and standards.
The MP&M technology options consist of groups of pollution prevention and
wastewater treatment technologies identified to reduce or eliminate the generation or discharge of
pollutants from MP&M sites. EPA identified these technologies from responses to the MP&M detailed
and screener surveys, MP&M site visits and sampling episodes, and technical literature (including case
studies and development documents for previously promulgated metals industry regulations).
9.1 Technology Evaluation Methods
MP&M sites generate wastewater containing oils, organic pollutants, cyanide,
hexavalent chromium, complexed metals, and dissolved metals. The MP&M industry uses many
different types of technologies to control and treat wastewater, including both in-process pollution
prevention technologies and end-of-pipe treatment and disposal technologies. To determine technology
options for each subcategory, EPA evaluated information collected from site visits, sampling episodes,
and MP&M screener and detailed surveys. EPA then grouped the most prevalent technologies
according to the type of wastewater which they treat (i.e., oily wastewater, metal-bearing wastewater,
cyanide-bearing wastewater, etc.). The Agency evaluated treatment efficiency in terms of percent
removal and final concentration (mg/L) from sampling episode data, discharge monitoring reports, and
periodic compliance reports.
EPA classified the technologies into one of the four tiers of the Environmental
Management Hierarchy (EMH) from EPA's Facility Pollution Prevention Guide (1). This hierarchy
attempts to prioritize technologies in order of importance or benefit to the environment from source
reduction (highest priority) to disposal (lowest priority). Tables 9-1 through 9-3, presented at the end
of this section, provide data on the technologies considered for the MP&M options, grouped by their
EMH classification as follows:
1. Table 9-1: Source reduction and pollution prevention technologies - EMH tier
1;
9-1
-------
9.0 - Technology Options
2. Table 9-2: Recycling technologies - EMH tier 2; and
3. Table 9-3: End-of-pipe treatment and disposal technologies - EMH tiers 3 and
4.
The tables present the following for each technology: a brief technology description; the
number of sites visited by EPA using the technology; the number of survey respondents reporting using
the technology; the estimated number of sites in the MP&M industry currently using the technology; and
comments noting if EPA included the technology in the MP&M technology options (as discussed in
Section 9.2) and, where appropriate, reasons why EPA did not include the technology. Each of the
pollution prevention, recycling and treatment technologies are described in detail in Section 8.0.
The demonstration of source reduction and some recycling technologies in the MP&M
industry was only quantifiable from the data collected in the MP&M 1996 detailed survey responses.
However, as shown on these tables, EPA observed most of these technologies during visits to MP&M
sites. The most frequently observed and/or reported source reduction and recycling technologies were:
Centrifugation of machining coolants;
Centrifugation of painting water curtains;
Conductivity probes;
Countercurrent cascade rinsing;
Drag-out rinsing;
Electrolytic recovery;
Flow restrictors;
In-tank filtration;
Ion exchange; and
Regeneration of process baths.
In addition, many of the sites that EPA visited used plant maintenance and good
housekeeping practices that resulted in source reduction.
Table 9-3 presents some of the most common end-of-pipe treatment technologies in
the MP&M industry:
• Chelation breaking/precipitation to remove complexed metals;
• Chemical emulsion breaking followed by gravity separation for oil removal;
• Chemical emulsion breaking followed by dissolved air flotation (DAF) for oil
removal;
• Chemical precipitation and gravity settling for solids removal;
• Chemical precipitation and microfiltration for solids removal;
• Chemical reduction of hexavalent chromium;
• Cyanide destruction through alkaline chlorination;
9-2
-------
9.0 - Technology Options
• Gravity settling of wastewater (without chemical addition);
• Gravity thickening of sludge;
• Multimedia filtration (including sand filtration);
• Neutralization (without solids removal);
• Pressure filtration of sludge; and
• Ultrafiltration for oil removal.
In addition, an estimated 31,000 of the 63,000 water-discharging MP&M sites
contract-haul some of their wastewater for off-site treatment and disposal. Many sites with treatment
technologies in place also contract-haul wastewater treatment sludges for off-site disposal.
9.2 Technology Options
EPA considered a technology to be demonstrated in the MP&M industry if the
technology effectively treated MP&M wastewater and if EPA observed the technology during at least
one MP&M site visit or at least one survey respondent reported using the technology. EPA evaluated
the performance of each technology using available analytical data from MP&M sampling episodes,
analytical data from previous effluent guidelines data collection efforts, and quantitative and qualitative
assessments from engineering site visits and literature.
EPA identified ten technology options for the MP&M industry subcategories. Table 9-
4 shows the options for each subcategory and the technologies used to establish effluent limitations and
standards. The following sections discuss the wastewater treatment technologies included in each
subcategory. Figures 9-1 through 9-6 present the technology trains for the options.
9.2.1 General Metals, Metal Finishing Job Shops, Printed Wiring Boards, Steel
Forming and Finishing, and Non-Chromium Anodizing Subcategories
EPA evaluated four wastewater treatment technology options for the MP&M industry
subcategories whose unit operations primarily produce metal-bearing wastewater (but may also
produce some oily wastewater). Each of these options are discussed below.
Option 1
Option 1 includes segregation of wastewater streams, preliminary treatment steps as
necessary (including oil removal using oil water separation by chemical emulsion breaking), chemical
precipitation using either sodium hydroxide or lime, and sedimentation using a clarifier. Segregation of
wastewater and subsequent preliminary treatment allows for the most efficient, effective, and economic
means for removing pollutants in certain wastewater streams. These streams contain pollutants (e.g., oil
and grease, cyanide, hexavalent chromium, chelated metals, and organic solvents) that can inhibit the
performance of chemical precipitation and sedimentation treatment, while increasing the overall
treatment costs. For example, if a facility segregates its oil-bearing wastewater from its metal-bearing
9-3
-------
9.0 - Technology Options
wastewater, then the facility can design an oil removal treatment technology based on only the oily
waste flow volume and not on the combined metal-bearing and oil-bearing wastewater flow, decreasing
the size of the overall treatment system. Treatment chemical costs are also reduced because of the
reduced volume. Preliminary treatment technologies for these types of wastewater streams are
described below. (See Section 5.0 for a more detailed description of each of these wastewater
streams).
• Oil-Bearing Wastewater. Alkaline cleaning wastewater and water-based
metal-working fluids (e.g., machining and grinding coolants) typically contain
significant amounts of oil and grease. These wastewater streams require
preliminary treatment to remove oil and grease and organic pollutants.
Chemical emulsion breaking followed by gravity separation of oil and water
(oil/water separator or gravity flotation) effectively removes these pollutants.
• Cyanide-Bearing Wastewater. The MP&M industry generates several
types of wastewater that may contain significant amounts of cyanide, such as
plating and cleaning wastewater. This wastewater requires preliminary
treatment to destroy the cyanide, typically performed using alkaline chlorination
with sodium hypochlorite or chlorine gas (3).
• Hexavalent Chromium-Bearing Wastewater. The MP&M industry
generates several types of wastewater that contain hexavalent chromium,
usually generated by acid treatment, anodizing, conversion coating, and
electroplating. Because hexavalent chromium does not form an insoluble
hydroxide and is not treated by chemical precipitation and sedimentation, this
wastewater requires chemical reduction of the hexavalent chromium to trivalent
chromium. Trivalent chromium forms an insoluble hydroxide and is treated by
chemical precipitation and sedimentation. Sodium metabisulfite or gaseous
sulfur dioxide are typically used as reducing agents for hexavalent chromium-
containing wastewater.
• Chelated Metal-Bearing Wastewater. Electroless plating and some
cleaning operations generate water that contains significant amounts of chelated
metals. This wastewater requires chemical reduction to break the metal-chelate
bond or reduce the metal-chelate complex to an insoluble state so that it can be
removed during chemical precipitation. Sodium borohydride, dithiocarbamate,
hydrazine, and sodium hydrosulfite are used as reducing agents.
• Organic Solvent-Bearing Wastewater. Option 1 also includes contract-
hauling of solvent degreasing wastewater. Based on the MP&M surveys and
site visits, most solvent degreasing operations which use organic solvents (e.g.,
1,1,1-trichloroethane, trichloroethene), are contract-hauled for off-site
9-4
-------
9.0 - Technology Options
recycling. Some MP&M sites reported using organic solvent-water mixtures or
rinses following organic solvent degreasing. EPA found contract-hauling of this
wastewater to be the most common disposal method for these sites.
After pretreatment of the segregated streams, chemical precipitation and gravity
clarification is used to remove total and dissolved metals. Chemical precipitation involves adjusting the
pH of the wastewater with alkaline chemicals such as lime (calcium hydroxide) or caustic (sodium
hydroxide) or acidic chemicals (such as sulfuric acid) to produce insoluble metal hydroxides. This step
is followed by a gravity settling process in a clarifier to remove the precipitated and flocculated metal
hydroxides by gravity settling (2). Segregation of wastewater streams, preliminary treatment, and final
chemical precipitation and gravity sedimentation is widely used throughout the metals industry and is
well documented as being effective in removing pollutants present in MP&M wastewater.
Option 2
Option 2 builds on Option 1 by adding in-process pollution prevention, recycling, and
water conservation methods that allow for recovery and reuse of materials. These technologies can
reduce manufacturing costs by allowing materials to be used over a longer period before they need to
be disposed. Using these techniques or technologies along with water conservation also leads to the
generation of less pollution and results in more effective treatment of the wastewater that is generated.
Specific Option 2 in-process pollution prevention, recycling and water conservation methods include:
• Countercurrent cascade rinsing for all flowing rinses;
• Centrifugation and recycling of painting water curtains; and
• Centrifugation and pasteurization to extend the life of water-soluble machining
coolants.
EPA observed these pollution prevention and water conservation technologies at
MP&M sites during site visits and sampling episodes. These technologies were also reported in the
MP&M surveys and documented in various literature sources (4,5).
Sites reducing their wastewater flow rates and increasing their influent pollutant
concentrations will more effectively treat the wastewater, reducing the mass of pollutants discharged in
the treated effluent. For example, a site that generates 2,600 gallons (10,000 liters) per day of raw
wastewater containing 10 mg/L of pollutants prior to treatment, implements water reduction and
recovery technologies that reduce the flow to 1,300 gallons (5,000 liters) per day and increase the
pollutant concentration to 20 mg/L prior to treatment. If the long-term average effluent concentration of
a pollutant was 0.1 mg/L, the site would discharge 1,000 mg/day of pollutant (10,000 L/day times 0.1
mg/L) prior to implementing flow reduction and recovery technologies, and 500 mg/day of pollutant
(5,000 L/day times 0.1 mg/L) after implementing the technologies.
9-5
-------
9.0 - Technology Options
EPA based the BPT, BCT and BAT proposed effluent limitations guidelines on Option
2 for existing direct dischargers in the General Metals, Metal Finishing Job Shops, Non-Chromium
Anodizing, Printed Wiring Board, and Steel Forming and Finishing Subcategories. EPA also based the
proposed pretreatment standards for existing sources (PSES) on Option 2 for the General Metals,
Metal Finishing Job Shops, Printed Wiring Boards, and Steel Forming and Finishing Subcategories.
EPA did not propose PSES nor pretreatment standards for new sources (PSNS) for the Non-
Chromium Anodizing Subcategory. EPA proposed new source performance standards (NSPS) for
new direct dischargers in the Non-Chromium Anodizing Subcategory based on Option 2.
Option 3
This option differs from Option 1 in that an ultrafilter replaces the chemical emulsion
breaking and oil/water separator for the removal of oil and grease, and a microfilter, rather than a
clarifier, follows chemical precipitation. Ultrafiltration is a separation technology that allows water and
small solute species to pass through a semi-porous membrane under pressure while emulsified oils are
retained by the membrane and recovered as concentrate (2). EPA determined through sampling
episodes that ultrafiltration systems are very effective for the removal of oil and grease at MP&M
facilities. Ultrafilters sampled by EPA achieved oil and grease removals of greater than 99 percent.
The emulsion breaking and gravity flotation system described in Options 1 and 2 removed
approximately 96 percent of the oil and grease from the MP&M wastewater.
Microfiltration uses a pressure-driven membrane process to separate wastewater
constituents based on size and shape. Using an applied pressure difference across a membrane, solvent
and small solute species pass through the membrane and are collected as permeate. Larger
constituents such as flocculated metal hydroxide particles generated during chemical precipitation are
retained by the membrane and recovered as a concentrated solids slurry. EPA collected treatment
effectiveness data for solids removal after chemical precipitation through microfiltration. Well-operated
chemical precipitation and microfiltration systems sampled by EPA at MP&M facilities achieved an
average removal of 99.6 percent for targeted metals. Well-operated chemical precipitation and gravity
clarification systems sampled by EPA at MP&M facilities achieved an average removal of 96.7 percent
for targeted metals.
Option 4
Option 4 includes technologies in Option 3 plus in-process flow control and pollution
prevention technologies described in Option 2, allowing for recovery and reuse of materials along with
water conservation. EPA based the NSPS and PSNS (new source) limitations and standards on
Option 4 for the General Metals, Metal Finishing Job Shops, Printed Wiring Boards, and Steel Forming
and Finishing Subcategories.
9-6
-------
9.0 - Technology Options
9.2.2 Oily Wastes Subcategory
EPA evaluated four wastewater treatment options for the Oily Wastes Subcategory.
EPA defines the Oily Wastes Subcategory as those facilities that only discharge wastewater from one
or more of the following unit operations: alkaline cleaning for oil removal, aqueous degreasing,
corrosion preventive coating, floor cleaning, grinding, heat treating, impact deformation, machining,
painting, pressure deformation, solvent degreasing, testing (e.g., hydrostatic, dye penetrant, ultrasonic,
magnetic flux), steam cleaning, and laundering. EPA is defining "corrosion preventive coating" as the
application of removable oily or organic solutions to protect metal surfaces against corrosive
environments. Corrosion preventive coatings include, but are not limited to: petrolatum compounds,
oils, hard dry-film compounds, solvent-cutback petroleum-based compounds, emulsions, water-
displacing polar compounds, and fingerprint removers and neutralizers. Corrosion preventive coating
does not include electroplating or chemical conversion coating (including phosphate conversion coating)
operations. Technology options used to establish effluent limitations are discussed below.
Option 5
Effluent limitations for Option 5 are based on end-of-pipe chemical emulsion breaking
followed by gravity separation using an oil/water separator. EPA performed sampling episodes at
several facilities in the Oily Wastes Subcategory that employed chemical emulsion breaking followed by
gravity flotation and oil skimming. These systems typically achieved a 96 percent removal of oil and
grease. Breaking the oil/water emulsion requires the addition of treatment chemicals such as acid, alum,
and/or polymers to change the emulsified oils or cutting fluids from hydrophilic colloids to aggregated
hydrophobic particles. The aggregated oil particles, with a density less than water, can be removed by
gravity flotation in a coalescing plate oil/water separator. This treatment train is widely used throughout
the metals industry and is well documented as effectively removing machining coolants, emulsified
hydraulic oils, and organic pollutants present in oily MP&M wastewater.
Option 6
Option 6 includes the technologies in Option 5 plus in-process flow control and
pollution prevention technologies, which allow for recovery and reuse of materials along with water
conservation. The specific Option 6 technologies include:
• Countercurrent cascade rinsing for all flowing rinses;
• Centrifugation and recycling of painting water curtains; and
• Centrifugation and pasteurization to extend the life of water-soluble machining
coolants.
9-7
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9.0 - Technology Options
EPA based the BPT, BCT, BAT, PSES, NSPS and PSNS effluent limitations
guidelines and pretreatment standards on Option 6 for the Oily Wastes Subcategory.
Option 7
Option 7 is based on end-of-pipe ultrafiltration. Ultrafiltration is a process that allows
water and small solute species to pass through a membrane under pressure while emulsified oils are
retained by the membrane and recovered as concentrate (2). Ultrafiltration removes oil droplets
ranging from 0.002 to 0.2-microns and is expected to generate a concentrated oil phase that is 2 to 5
percent of the influent volume. Sampling episode data determined that, on average, ultrafilters will
remove greater than 99 percent of all oil and grease in the influent stream. Ultrafiltration is widely used
throughout the MP&M industry and is well documented as effectively treating machining coolants,
emulsified hydraulic oils, and organic pollutants present in oily MP&M wastewater.
Option 8
Option 8 includes the Option 7 technology (ultrafiltration) plus the pollution prevention
and water conservation alternatives described in Option 6. Although EPA is not proposing Options 7
or 8, they were evaluated as potential options for the Oily Wastes, Shipbuilding Dry Dock, and
Railroad Line Maintenance Subcategories.
9.2.3 Shipbuilding Dry Dock and Railroad Line Maintenance Subcategories
EPA evaluated four wastewater treatment technology options for the Shipbuilding Dry
Docks and Railroad Line Maintenance Subcategories. For these Subcategories, EPA considered
Options 7 and 8 in addition to the two technology options discussed below.
Option 9
Option 9 is based on end-of-pipe chemical emulsion breaking followed by DAF to
remove flocculated oils. Breaking the oil/water emulsions requires adding treatment chemicals such as
acid, alum and/or polymers to change the emulsified material from a hydrophilic colloidal dispersion to
aggregate hydrophobic particles. In the DAF tank, air bubbles created as a result of a rapid pressure
drop attach to the aggregated oil particles and pull them to the surface of the tank. A scraping
mechanism collects the oil and solids from the surface of the DAF tank. This treatment train is
demonstrated in both the shipbuilding dry dock and railroad line maintenance Subcategories and is
effective for removing emulsified oils and suspended solids.
Option 10
Option 10 includes the end-of-pipe treatment technologies included in Option 9
(chemical emulsion breaking followed by DAF) plus in-process flow control and pollution prevention
9-8
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9.0 - Technology Options
technologies, which allow for recovery and reuse of materials along with water conservation. The
specific Option 10 in-process technologies include:
• Countercurrent cascade rinsing for all flowing rinses;
• Centrifugation and recycling of painting water curtains; and
• Centrifugation and pasteurization to extend the life of water soluble machining
coolants.
EPA based the BPT, BCT, BAT and NSPS effluent limitations guidelines and
pretreatment standards for the Shipbuilding Dry Dock and Railroad Line Maintenance Subcategories
on Option 10. EPA did not propose pretreatment standards for new or existing sources in the
Shipbuilding Dry Dock and Railroad Line Maintenance Subcategories.
9.3 References
1. U.S. Environmental Protection Agency. Facility Pollution Prevention Guide.
EPA/600/R-92/088, Washington, DC, 1992.
2. Freeman, H.M. Standard Handbook of Hazardous Waste Treatment and Disposal.
McGraw Hill Publishing Company, New York, New York, 1989.
3. Cherry, K.F. Plating Waste Treatment. Ann Arbor Sciences Publishers, Inc., Ann
Arbor, Michigan, 1982.
4. Freeman, H.M. Hazardous Waste Minimization. McGraw Hill Publishing Company,
New York, New York, 1990.
5. Cushnie, George C. Pollution Prevention and Control Technology for Plating
Operations. National Center for Manufacturing Sciences, 1994.
9-9
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9.0 - Technology Options
Table 9-1
EMH Tier 1 - MP&M Source Reduction and Pollution Prevention Technologies
Technology
Technology Description
Demonstration Status
Number
of Sites
Visited3
Number
of
Survey
Sites0
Estimated
Number of
MP&M Sites
Using the
Technology0
Comments
Conductivity Probes
9-10
Measure the conductivity of water in a rinse tank to
regulate the flow of fresh rinse water into the rinse system.
A solenoid valve on the rinse system fresh water supply is
connected to the controller, which opens the valve when a
preset conductivity level is exceeded and closes the valve
when conductivity is below that level.
38
29
320
This technology reduces the
amount of water necessary for
rinsing.
The MP&M cost model evaluates
the level of rinse flow control in
place prior to estimating costs for
countercurrent cascade rinsing.
Countercurrent
Cascade Rinsing
Series of consecutive rinse tanks that are plumbed to
cause water to flow from one tank to another in the
direction opposite of the work flow. Water is introduced
into the last tank of the series, making it the cleanest, and
is discharged from the first tank, which has the highest
concentration of pollutants.
94
130
1569
This technology reduces the
amount of water necessary for
rinsing. This technology is
included in the technology options.
Drag-Out Rinsing
Stagnant rinse, initially of fresh water, positioned
immediately after process tanks. The drag-out rinse
collects most of the drag-out from the process tank,
preventing it from entering the subsequent flowing rinses.
58
139
1737
This technology reduces the
amount of water necessary for
rinsing. The MP&M cost model
evaluates the level of rinse water
use prior to estimating costs for
countercurrent rinsing.
Flow Restrictors
Prevent the flow in a pipe from exceeding a predetermined
volume. Flow restrictors can be used to limit the flow into
a rinse system. For continuously flowing rinses, a flow
restrictor controls the flow into the system, ensuring a
consistent, optimum flow rate.
45
127
1581
This technology reduces the
amount of water necessary for
rinsing. The MP&M cost model
evaluates the level of rinse flow
control in place prior to estimating
costs for countercurrent cascade
rinsing.
-------
Table 9-1 (Continued)
9.0 - Technology Options
Technology
Technology Description
Demonstration Status
Number
of Sites
Visited3
Number
of
Survey
Sites0
Estimated
Number of
MP&M Sites
Using the
Technology0
Comments
Spray Rinsing
Spray water on parts above a process tank or drip/drag-
out tank; Uses considerably less water than immersion for
certain part configurations. This technology can also be
performed as countercurrent cascade rinsing with spray
rinses instead of overflow immersion rinses.
64
187
1767
Not applicable at all sites because
of part and process configurations;
not included in the technology
options.
9-11
Centrifugation of
Painting Water
Curtains
Removes the heavier solids from the water curtain
allowing the water to be reused. The solids are collected
as a cake in the basket of the centrifuge. This technology
can achieve closed-loop reuse of water curtains.
12
Requires little maintenance, and has
been demonstrated to achieve
complete recycle with periodic
removal of sludge. This technology
is included in the technology
options.
Filtration of Painting
Water Curtains
Removes solids by filtration (cloth, sand, diatomaceous
earth, etc.) followed by reuse. This technology can
achieve closed-loop reuse of water curtains.
20
Generates more waste than
centrifugation due to filter medium
disposal or sand filter backwash.
This technology is not included in
the technology options.
Settling of Painting
Water Curtains
Removes the heavier solids from the water curtains. This
technology can be used in conjunction with other removal
technologies to lessen the solids loading.
23
Equivalent technology
(centrifugation) is included as part
of the technology options;
therefore, this technology is not
included in the technology options.
Biocide Addition to
Lengthen Coolant Life
Can impede the growth of microorganisms that cause
rancidity. Machining coolant is often discarded as it
becomes rancid.
27
216
Equivalent technology
(pasteurization) is included as part
of the technology options;
therefore, this technology is not
included in the technology options.
-------
9.0 - Technology Options
Table 9-1 (Continued)
Technology
Centrifugation to
Lengthen Coolant Life
Filtration to Lengthen
Coolant Life
Skimming of Tramp
Oils to Lengthen
Coolant Life
Pasteurization to
Lengthen Coolant Life
Technology Description
Removes the solids from the coolant to extend its usable
life. Some high-speed centrifuges can also perform liquid-
liquid separation to remove tramp oils and further extend
coolant life.
Removes the solids from the coolant using filters such as
cloth, sand, carbon, etc.
Extends the coolant life. Tramp oil buildup often makes
machining coolant unusable.
Kills the microorganisms that cause rancidity. Machining
coolant is often discarded as it becomes rancid.
Demonstration Status
Number
of Sites
Visited3
18
18
8
1
Number
of
Survey
Sites0
10
18
9
2
Estimated
Number of
MP&M Sites
Using the
Technology0
78
142
82
18
Comments
This is a component of the coolant
recycling system included in the
technology options.
Equivalent technology is included
as part of the technology options;
therefore, this technology is not
included in the technology options.
Equivalent technology (liquid-liquid
centrifugation) is included as part of
the technology options; therefore,
this technology is not included in
the technology options.
This is a component of the coolant
recycling system included in the
technology options.
9-12
EMH - Environmental Management Hierarchy.
NA - Numerical data are not available.
Source: MP&M site visits, MP&M sampling episodes, MP&M surveys and technical literature.
indicates the number of MP&M sites visited by EPA using the listed technology. EPA visited a total of 162 sites.
bNumber of survey sites based on data collected in 1996 only. The 1989 survey did not request this information.
Indicates the estimated number of MP&M sites currently performing this technology based on the 1996 Detailed Survey Results. EPA estimates that the MP&M industry
includes 63,000 wastewater discharging sites. EPA estimated numbers in this column using statistical weighting factors for the 1996 MP&M Detailed survey respondents.
-------
Table 9-2
9.0 - Technology Options
EMH Tier 2 - MP&M Recycling Technologies
Technology
Evaporation with
Condensate
Recovery
Ion Exchange
Reverse Osmosis
Technology Description
Leaves a concentrated residue for disposal and condenses
the water vapor for reuse.
Combined cation and anion exchange used to remove metal
salts from electroplating rinsewater. Effluent from the ion
exchange is returned to the electroplating rinse system. Ion
exchange regenerants are either discharged to the end-of-
pipe chemical precipitation unit for metals removal, or
metals are recovered by electrowining.
Forces wastewater through a membrane at high pressure,
leaving a concentrated stream of pollutants for disposal.
Reverse osmosis may provide an effluent clean enough for
reuse.
Demonstration Status
Number
of Sites
Visited3
4
29
2
Number
of
Survey
Sites"
15
33
1
Estimated
Number of
MP&M Sites
Using the
Technology0
147
437
3
Comments
Energy -intensive. This technology
is not included in the technology
options.
Permeate contains moderate
dissolved solids concentrations and
may be reused in noncritical unit
operations. This technology is not
included in the technology options.
While the technology may be
effective for individual sites EPA
cost estimates show that ion
exchange is not cost effective for
the industry as a whole.
Similar in application to end-of-pipe
ion exchange, but not as well
demonstrated. This technology is
not included in the technology
options.
9-13
-------
9.0 - Technology Options
Table 9-2 (Continued)
Technology
Electrolytic Recovery
(Electrowinning)
Technology Description
Recovers dissolved metals from concentrated sources. For
rinses, electrolytic recovery is typically restricted to drag-
out rinses. Flowing rinses are generally too dilute for
efficient electrolytic recovery. This technology is effective
on the concentrated regenerant from ion exchange.
Demonstration Status
Number
of Sites
Visited3
19
Number
of
Survey
Sites"
23
Estimated
Number of
MP&M Sites
Using the
Technology0
142
Comments
Works in conjunction with drag-out
rinsing and in-process ion exchange
to recover metals from wastewater.
This technology is not included in
the technology options.
EMH - Environmental Management Hierarchy.
NA - Numerical data are not available.
n iSource: MP&M site visits, MP&M sampling episodes, MP&M surveys and technical literature.
indicates the number of MP&M sites visited by EPA using the listed technology. EPA visited a total of 162 sites.
bNumber of survey sites based on data collected in 1996 only. The 1989 survey did not request this information.
Indicates the estimated number of MP&M sites currently performing this technology based on the 1996 Detailed Survey Results. EPA estimates that the MP&M industry
includes 63,000 wastewater discharging sites. EPA estimated numbers in this column using statistical weighting factors for the 1996 MP&M Detailed survey respondents.
-------
9.0 - Technology Options
Table 9-3
EMH Tiers 3 and 4 - MP&M End-of-Pipe Treatment and Disposal Technologies
Technology
Chemical Emulsion
Breaking Followed by
Gravity Oil/Water
Separation
Chemical Reduction of
Hexavalent Chromium
Cyanide Destruction
Through Alkaline
Chlorination
Chemical Emulsion
Breaking Followed by
DAF
Oil Skimming of Oily
Wastewater Streams
Cyanide Oxidation by
Ozone
Technology Description
Adds acids (typically sulfuric), polymer, and sometimes alum to
oil-bearing wastewater to break oil/water emulsions for
subsequent gravity separation.
Reduces hexavalent chromium to bivalent chromium using a
reducing agent such as sulfur dioxide, sodium bisulfite, or sodium
metabisulfite.
Destroys cyanide by adding chlorine (usually sodium
hypochlorite or chlorine gas) to first oxidize cyanide to cyanate,
then cyanate to carbon dioxide and nitrogen gas.
Adds acids (typically sulfuric), polymer, and sometimes alum to
oil-bearing wastewater to break oil/water emulsions for
subsequent gravity separation. Removes oils and solids by
bubbling gas through the wastewater, bringing solids to the
surface for subsequent removal.
Removes free floating oil by gravity separation and mechanical
skimming. This technology does not remove emulsified oils.
Ozone oxidizes cyanide to ammonia, carbon dioxide and oxygen.
Demonstration Status
Number
of Sites
Visited"
11
74
52
12
38
0
Number
of
Survey
Sites"
56
103
53
25
89
1
Estimated
Number of
MP&M Sites
Using the
Technology0
958
1,839
1,136
244
2,087
4
Comments
This technology is included in the
technology options.
This technology is included in the
technology options.
This technology is included in the
technology options.
This technology is included and has
been costed in the technology options
for shipbuilding dry docks and railroad
line maintenance subcategories.
Not as effective as chemical emulsion
breaking followed by gravity flotation
using an oil/water separator or DAF.
This technology is not included in the
technology options.
The generation of ozone requires
expensive equipment and safety
controls. An equivalent technology
(cyanide destruction through alkaline
chlorination) is included in the
technology options. Therefore, this
technology is not included in the
technology options.
-------
9.0 - Technology Options
Table 9-3 (Continued)
Technology
Chelation Breaking/
Precipitation to Remove
Complexed Metals
Ultrafiltration
Activated Carbon
Adsorption
Aerobic Biological
Treatment
Air Stripping
Technology Description
Wastewater from electroless plating and some cleaning
operations contains chelated metals which cannot be removed by
chemical precipitation. Strong reducing agents such as
dithiocarbamate are added to break the metal-organic chelate
bond and precipitate the metal.
Generally used to remove emulsified or free-floating oils. This
technology also removes other solids. Uses a membrane of very
small pore size.
Removes dissolved organic pollutants by filtration through
activated carbon. The dissolved organics are removed by the
process of adsorption. This technology requires preliminary
treatment to remove suspended solids and oil and grease.
Biochemically decomposes organic materials in the presence of
oxygen. The decomposition is performed by microorganisms.
Removes dissolved volatile organic pollutants by contacting the
organics in the wastewater with a continuous stream of air
bubbles. Volatile organic pollutants are transferred from the
wastewater to the air.
Demonstration Status
Number
of Sites
Visited"
11
17
8
1
0
Number
of
Survey
Sites"
49
23
21
4
2
Estimated
Number of
MP&M Sites
Using the
Technology0
555
351
165
130
14
Comments
Used to treat electroless plating
wastewater prior to chemical
precipitation. This technology is
included and costed in the technology
options.
This technology is included in the
technology options for new sources.
Applicable to wastewater containing
dilute concentrations of nonpolar
organic pollutants. MP&M treatment
influent streams typically do not
contain dilute concentrations of
nonpolar organic pollutants. This
technology is not included in the
technology options.
Applicable to wastewater with high
concentrations of organic pollutants.
MP&M treatment influent streams
typically do not contain high
concentrations of organic pollutants.
EPA visited one site that operated this
technology to treat nonprocess
wastewater. This technology is not
included in the technology options.
Applicable to wastewater containing
high concentrations of volatile organic
pollutants. MP&M treatment influent
streams typically do not contain high
concentrations of volatile organic
pollutants. This technology is not
included in the technology options.
9-16
-------
9.0 - Technology Options
Table 9-3 (Continued)
Technology
Neutralization
Chemical Precipitation
and Gravity
Sedimentation
Chemical Precipitation
and Membrane Filtration
Atmospheric
Evaporation
Ion Exchange
Technology Description
Acidic or alkaline chemicals used to neutralize high or low pH
wastewater to within an acceptable range. Common acids
include sulfuric and hydrochloric. Common alkaline chemicals
include lime (calcium hydroxide) and sodium hydroxide.
Removes metals by precipitating insoluble compounds such as
hydroxides, sulfides, or carbonates. Precipitation as metal
hydroxides using lime (calcium hydroxide) or sodium hydroxide
is the most common. Precipitated and flocculated solids are
removed by gravity sedimentation in a clarifier.
Removes metals by precipitating insoluble compounds such as
hydroxides, sulfides, or carbonates. Precipitation as metal
hydroxides using lime (calcium hydroxide) or sodium hydroxide
is the most common. Precipitated and flocculated solids are
removed by micro filtration through a porous membrane.
Includes both natural solar evaporation and forced atmospheric
evaporation by which the evaporation rate is accelerated by
increased temperature, air flow, and surface area.
Polishing technique after metals precipitation to scavenge low
concentrations of residual metals (cations). Anions remain in
solution and are discharged. Concentrated metal containing
regenerants are typically returned to the metals precipitation
system.
Demonstration Status
Number
of Sites
Visited"
51
117
5
3
13
Number
of
Survey
Sites"
233
203
5
12
39
Estimated
Number of
MP&M Sites
Using the
Technology0
3,713
2,981
36
142
251
Comments
Adjusts pH, but does not remove
suspended solids and dissolved metals.
This technology is not included in the
technology options.
This technology is included and costed
in the technology options.
This technology is included and costed
in the new source technology options.
Usually occurs in ponds or lagoons
with large space requirements. Also,
atmospheric evaporators have
significant energy requirements as well
as possible cross-media impacts. This
technology is not included in the
technology options.
Usually used in conjunction with
another end-of-pipe technology (e.g.,
following chemical precipitation).
Based on analytical data collected
during the MP&M sampling program,
this technology does not provide
significant metal removals beyond
chemical precipitation and
sedimentation. This technology is not
included in the technology options.
9-17
-------
9.0 - Technology Options
Table 9-3 (Continued)
Technology
Multimedia Filtration
Sand Filtration
Gravity Settling
Centrifugation of Sludge
Technology Description
Uses filter media of different grain size to remove solids from
wastewater. Larger particles are removed by the coarser media
and the smaller particles are removed by the finer media. Media
include garnet, sand, and anthracite coal. The filter is
periodically backwashed to remove solids.
Uses a sand filter to remove solids from wastewater. The filter
is periodically backwashed to remove solids.
Physically removes suspended particles by gravity. This
process does not include the addition of any chemicals.
Uses centrifugal force to separate water from solids.
Centrifugation dewaters sludges, reducing the volume and
creating a semisolid cake. Centrifugation of sludge can typically
achieve a sludge of 20-35% solids.
Demonstration Status
Number
of Sites
Visited"
11
37
7
4
Number
of
Survey
Sites"
16
41
46
9
Estimated
Number of
MP&M Sites
Using the
Technology0
354
830
1,679
127
Comments
Usually used in conjunction with
another end-of-pipe technology (e.g.,
following chemical precipitation).
Based on analytical data collected
during the MP&M sampling program,
this technology does not provide
significant additional metal removals
beyond chemical precipitation and
sedimentation. EPA evaluated this
technology in the BCT technology
options.
Usually used in conjunction with
another end-of-pipe technology (e.g.,
following chemical precipitation).
Based on analytical data collected
during the MP&M sampling program,
this technology does not provide
significant metal removals beyond
chemical precipitation and
sedimentation. This technology was
not included in the technology options.
Only settles suspended solids and does
not remove dissolved metals. This
technology is not included in the
technology options.
Energy intensive, and is therefore not
included in the technology options.
Equivalent sludge dewatering
technologies (gravity thickening and
pressure filtration) are included and
costed in the technology options.
9-18
-------
9.0 - Technology Options
Table 9-3 (Continued)
Technology
Gravity Thickening of
Sludge
Pressure Filtration of
Sludge
Sludge Drying
Vacuum Filtration of
Sludge
Technology Description
Physically separates solids and water by gravity. Water
separates from the sludge and is decanted from the top of the
mixture. Gravity thickening can typically thicken sludge to 5%
solids.
Physically separates solids and water by pressure filtration.
Most commonly performed in a plate-and-frame filter press
where the sludge builds up between the filter plates and water is
filtered through a cloth. Pressure filtration can produce a sludge
cake with greater than 40% solids.
Dries sludge by heating, which causes the water in the sludge to
evaporate.
The MP&M cost model evaluates the level of rinse flow control
in place prior to estimating costs for countercurrent cascade
rinsing.
Demonstration Status
Number
of Sites
Visited"
60
113
22
8
Number
of
Survey
Sites"
85
189
48
9
Estimated
Number of
MP&M Sites
Using the
Technology0
1,161
3,106
835
193
Comments
This technology is included and costed
in the technology options.
This technology is included in the
technology options.
This technology is energy intensive, and
is therefore not included in the
technology options. Equivalent
technologies (gravity thickening and
pressure filtration) are included in the
technology options.
Energy intensive and typically does not
achieve as high a percent solids as
pressure filtration. This technology is
not included in the technology options.
Equivalent sludge dewatering
technologies (gravity thickening and
pressure filtration) are included in the
technology options.
9-19
EMH - Environmental Management Hierarchy.
NA - Numerical data are not available.
Source: MP&M site visits, MP&M sampling episodes, MP&M surveys and technical literature.
indicates the number of MP&M sites visited by EPA using the listed technology. EPA visited a total of 162 sites.
Indicates the number of model sites that reported using this technology. Based on 691 MP&M survey respondents.
Indicates the estimated number of MP&M sites currently performing this technology. EPA estimates that the MP&M industry includes 63,000 wastewater discharging sites.
EPA estimated numbers in this column using statistical weighting factors for the MP&M survey respondents.
-------
Table 9-4
9.0 - Technology Options
Technology Options by Subcategory
Treatment or Source Reduction
Technology
Chemical Precipitation
Gravity Clarification for Metal Hydroxide
Removal
Microfiltration for Metal Hydroxide Removal
Emulsion Breaking and Gravity Separation for
Oil Removal
Ultrafiltration for Oil Removal
Emulsion Breaking and DAF for Oil Removal
Alkaline Chlorination for Cyanide Removal
Hexavalent Chromium Reduction
Reduction/Precipitation of Chelated Metals
Contract Hauling of Organic Solvent-Bearing
Wastewater
Countercurrent Cascade Rinsing
Centrifugation and Recycling of Painting
Water Curtains
Centrifugation and Pasteurization to Extend
Life of Water Soluble Machining Coolants
General Metals, Metal Finishing Job Shops,
Printed Wiring Boards, Steel Forming and
Finishing, and Non-Chromium Anodizing
Subcategories
Option 1
•
•
•
•
•
•
•
Option 2
•
•
•
•
•
•
•
•
•
•
Option 3
•
•
•
•
•
•
•
Option 4
•
•
•
•
•
•
•
•
•
•
Oily Waste Subcategory
Option 5
•
•
Option 6
•
•
•
•
•
Option
T
•
•
Option
8a
•
•
•
•
•
Shipbuilding Dry
Dock and Railroad
Line Maintenance
Subcategories
Option 9
•
•
Option 10
•
•
•
•
•
9-20
DAF: Dissolved air flotation
"EPA evaluated this option for Shipbuilding Dry Dock and Railroad Line Maintenance Subcategories along with Options 9 and 10.
-------
GENERAL METAL-BEARING
WASTEWATER
9.0 - Technology Options
REDUCING AGENT
9-21
HEXAVALENT CHROMIUM-
BEARING WASTEWATER
CYANIDE-BEARING
WASTB/VATER
OILY WASTB/VATER
REDUCIls
CHELATED METAL-
BEARING WASTEWATER
1
Chromium
Reduction
OXIDIZING AGENT
1
Cyanide
Destruction
Chemical
Emulsion
Breaking
JG/PRECIPTTATIONA
1
Chelated
Metals
Treatment
i
i
GENT
< \
i i
OIL TO RECLAIM
t
Gravity
Oil/ Water *
Separation
PRECIPTTATION
AND
FLOCCULATION
CHEMICALS
4
, Chemical Solids Removed
- * Precipitation * !? ¥*P
Clanfication
SLUDGE
Sludge 4
FILTRATE Dewatering
.SLUDGE TO
* DISPOSAL
WASTEWATER
DISCHARGE
SOLVENT-BEARING
WASTEWATER
Contract
Hauling
OFF-SFTE TREATMENT
AND DISPOSAL
Figure 9-1. End-of-Pipe Treatment Train for Options 1 and 2 Considered for the Following Subcategories:
General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Boards, and Steel Forming and Finishing
-------
9.0 - Technology Options
9-22
RECYCLED WATER
V
Painting Water
Curtains
1
Centrifuge
i k
p*m WASTEWATER
FRESH SLUDGE
WATER WATER
L
Cleaning or PRODUCTS PRODUCTS
riniainny w w
Operation RECYCLED
.
PRODUCT i '
FLOW
Countercurrent Machining
Cascade Rinse Coolant
OIL TO
RECLAIM
COOLANT A
_L
Centrifuge and
Pasteurization
" 1
DISCHARGE
TO
TREATMENT
SPENT COOLANT SLUDGE
Figure 9-2. In-Process Water Use Reduction Technologies for Options 2 and 4 Considered for the Following Subcategories:
General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Boards,
and Steel Forming and Finishing
-------
9.0 - Technology Options
GENERAL METAL-BEARING
9-23
WASTEWATER
HEXAVALENT CHROMIUM-
BEARING WASTEWATER
CYANIDE-BEARING
WASTEWATER
OILYWASTEWATER
REDUCI
CHELATED METAL-
BEARING WASTEWATER
SOLVENT-BEARING
WASTEWATER
REDUCING AGENT
1
Chromium
Reduction
OXIDIZING AGENT
1
Cyanide
Destruction
OIL TO RECLAIM
t
Ultrafiltration
MG/PRECIPFTATIONy
1
Chelated
Metals
Treatment
Contract
Hauling
i
t
\GEm
t
w
f i
l i
OFF-SrTE TREATMENT
AND DISPOSAL
PRECIPFTATDN
AND
FLOCCULATON
CHEMICALS
1
r ^ Chemical h Sollds Removed WASTEWATER
k ^ Precioitation By DISCHARGE
\\ CwllJILdLIUI 1 . _. t-ti. i-
Microfiltration
SLUDGE
Sludge ^
FILTRATE Dewatering
fc SLUDGE TO
* DISPOSAL
Figure 9-3. End-of-Pipe Treatment Train for Options 3 and 4 Considered for the Following Subcategories:
General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Boards, and Steel Forming and Finishing
-------
9.0 - Technology Options
Polymer,
Alum,
Acid
Oil to Reclaim
9-24
Oily
Wastewater
Chemical
Emulsion
Breaking
Gravity
Oil/Water
Separation
Wastewater
Discharge
Figure 9-4. End-of-Pipe Treatment Train for Options 5 and 6
Considered for the Oily Wastes Subcategory
-------
9.0 - Technology Options
Oil to Reclaim
Oily
Wastewater
Ultrafiltration
Wastewater
Discharge
9-25
Figure 9-5. End-of-Pipe Treatment Train for Option 7 and 8
Considered for the Following Subcategories: Oily Wastes,
Railroad Line Maintenance, Shipbuilding Dry Dock
-------
9.0 - Technology Options
Acid Polymer
Oil to Reclaim
9-26
Oily
Wastewater
V 1
r
Chemical
Emulsion
Breaking
^
i
L
Dissolved
Air
Flotation
Wastewater
Discharge
Figure 9-6. End-of-Pipe Treatment Train for Options 9 and 10 Considered for the
Railroad Line Maintenance and Shipbuilding Dry Dock Subcategories
-------
io.o LONG-TERM AVERAGES AND VARIABILITY FACTORS
This section summarizes the technology effectiveness evaluation and the long-
term average (LTA) concentrations and variability factors calculated for the selected end-of-pipe
MP&M wastewater treatment technologies. These technologies are:
• Chemical precipitation and clarification (using sedimentation or
membrane filtration) with preliminary treatment, where applicable, for
treatment of regulated metals and suspended solids. Preliminary treatment
may include chromium reduction, batch chemical precipitation for
concentrated waste streams, and chemical reduction/precipitation of
chelated metals.
• Ultrafiltration for treatment of oil and grease and organic pollutants.
• Dissolved air flotation (DAF) for treatment of oil and grease and organic
pollutants.
• Chemical emulsion breaking and oil-water separation for treatment of oil
and grease and organic pollutants.
• Cyanide destruction with alkaline chlorination for treatment of cyanide.
Section 8.3 describes these technologies in detail, as well as the physical and
chemical principles underlying their operation. Section 3.3 describes EPA's data-gathering
activities at MP&M sites that use each of these technologies.
This section describes the data sources used in the technology effectiveness
evaluation (Section 10.1); the data-editing procedures used in assessing the technologies (Section
10.2); and the LTA concentrations, variability factors, and limitations calculated from this
assessment (Sections 10.3 and 10.4).
EPA used the following methodology to estimate the daily maximum and monthly
average limitations for the regulated pollutants:
1. Identify the sampling episodes that match the technology option (Section
10.1).
2. Evaluate the data from each episode to identify data that demonstrate
effective treatment (Section 10.2).
3. Calculate the LTA for each sampling episode data set from the daily
effluent concentrations for each pollutant passing the technology
effectiveness evaluation. The episode-level LTA for each pollutant is the
arithmetic average of the daily concentration at each sampling episode.
For samples where a pollutant was not detected, EPA used the sample
detection limit to calculate the LTA. The Agency defined the LTA for
each pollutant as the median of the episode-level LTAs (Section 10.3.4).
10-1
-------
10.0 - Long-Term Averages and Variability Factors
4. Use the modified delta-lognormal model to estimate episode-level daily
and episode-level 4-day average variability factors (Section 10.3.1) for
those episode data sets that had at least four samples of a pollutant passing
the technology effectiveness evaluation, including at least two detected
values.
5. Determine the daily variability factor and the 4-day average variability
factor. EPA defines the daily variability factor for a pollutant as the
average of the episode-level daily variability factors and defines the 4-day
average variability factor as the average of the episode-level 4-day average
variability factors (Section 10.3.5).
6. Calculate the daily and monthly average limitations by multiplying the
constituent LTA by the daily and 4-day constituent variability factors,
respectively (Section 10.3.7).
10.1 Sources of Technology Performance Data
EPA, industry, and local sanitation districts collected data from wastewater
treatment systems during separate sampling episode programs conducted at MP&M facilities.
Sampling episode reports maintained in the administrative record for this rulemaking present the
data collected during each sampling episode. All sampling episodes were conducted using the
EPA sampling and chemical analysis protocols as described in Section 3.3. The following
subsections describe sampling programs conducted by EPA and other entities as well as industry-
supplied monitoring data.
To determine the limits for each subcategory for each technology option, EPA
subdivided the data by subcategory and technology option. Section 7.0 discusses regulated
pollutants for MP&M subcategories. Table 10-1 lists the number of evaluated treatment systems
per subcategory.
10.1.1 EPA Sampling Program
EPA conducted 57 sampling episodes at MP&M sites ranging from one to five
days as discussed in Section 3.3. To assess possible influent and effluent variability caused by
variations in site operations, EPA conducted multiple sampling episodes at three of these sites.
Data from these sampling episodes are stored in the LTA Database. Table 10-2 summarizes the
number of sampling episodes and data points in the LTA Database from EPA-conducted
sampling episodes.
For some sampling points on some days, EPA collected duplicate samples for
quality assurance checks, or multiple sample fractions to develop manual composite samples.
EPA averaged the concentrations as described below for evaluating treatment performance and
calculating long-term averages and variability factors.
10-2
-------
10.0 - Long-Term Averages and Variability Factors
• Duplicate samples. As discussed in Section 4.0, EPA collected duplicate
samples at many sampling points as a quality control measure. EPA
averaged the concentrations for the original and duplicate samples for each
parameter. For samples where a pollutant was not detected in a sample,
EPA used the sample detection limit to calculate the average.
• Multiple composite fractions. EPA collected multiple grab composite
samples for oil and grease and total petroleum hydrocarbons. For these
samples, EPA averaged the composite results over the sample day. When
a pollutant was not detected in a sample, EPA used the sample detection
limit to calculate the average.
10.1.2 Sampling Episodes Conducted by Industry and Local Sanitation Districts
Local sanitation districts and the industry conducted sampling episodes ranging
from three to five days as discussed in Section 3.3. To assess possible influent and effluent
variability caused by variations in site operations, sanitation districts conducted multiple
sampling episodes at two sites, one of which EPA also sampled. Data from these sampling
episodes are stored in the LTA Database. Table 10-3 summarizes the number of sampling
episodes and data points in the LTA Database associated with samples collected by industry and
local sanitation districts.
10.1.3 Industry-Supplied Effluent Monitoring Data
To augment data collected during sampling episodes, EPA requested effluent
monitoring data from sampled sites to further evaluate and refine variability factors. EPA
attempted to obtain effluent monitoring data that represented each regulated subcategory and
each technology option and used industry effluent data that met the following criteria:
• Data were from a treatment system passing all criteria in the technology-
effectiveness evaluation (see Section 10.2).
• The site collected effluent monitoring data from a location comparable to
the one used by EPA during the sampling episode (e.g., the site did not
typically commingle the effluent with other waste streams, such as storm
water or sanitary waste, before the sampling point). As an exception, EPA
used a site's data even when the monitoring location followed pH
adjustment, since this treatment step would not change the concentrations
of regulated pollutants.
• Wastewater treatment processes were comparable to those at the time of
the sampling episode (i.e., no changes were made to the system that could
change treatment effectiveness). If the wastewater treatment process had
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been modified, EPA requested data for a period when the treatment
processes were similar to those at the time of the sampling episode.
• Wastewater treatment influent characteristics were comparable to those at
the time of the sampling episode (i.e., the site made no major
manufacturing process changes that would change the influent
characteristics). If changes had occurred subsequent to the sampling
episode, EPA requested data for a period when processes were similar to
those during the sampling episode.
EPA collected data during site visits and sampling episodes, from voluntary
submissions by sites, or by written request. The database contained additional effluent data from
14 sites. Table 10-4 summarizes supplementary effluent monitoring data obtained from sites.
Because these data are not in a form that allows direct use for calculating limits or for
comparison to the proposed limits, EPA was not able to use these data in setting or evaluating the
compliance aspects of the proposed limits and standards. However, following proposal, EPA
will reformat and evaluate these long-term effluent monitoring data in relation to the proposed
limits.
10.2 Evaluation of Treatment Effectiveness
EPA reviewed MP&M sampling data to identify data from well-designed and
well-operated treatment systems to calculate the LTA concentrations and variability factors.
During the review, EPA focused on data for pollutants processed and treated by the MP&M
industry. Figure 10-1 summarizes the technology effectiveness data-editing procedures discussed
in this section. As shown on this figure, the data editing process consisted of four major steps:
1. Identification of pollutants not present in the raw wastewater at sufficient
concentrations to evaluate treatment effectiveness;
2. Assessment of general performance of the treatment system;
3. Identification of process upsets that could affect treatment effectiveness
and sampling techniques that could affect data quality; and
4. Identification of wastewater treatment chemicals.
EPA did not calculate LTAs for pollutants that were not MP&M pollutants of
concern (see Section 7.0). The LTA database contains 59,211 influent and effluent data points
for MP&M pollutants of concern associated with the MP&M end-of-pipe technology options. Of
these data points, 29,639 were influent data points. A data point is a concentration of a specific
constituent from a given sampling day at a sampled point.
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Identification of pollutants in the wastewater at sufficient
concentrations to evaluate removal:
(1) Pollutant not detected in any (Flag=N) raw influent
samples to a treatment system.
(2) Pollutant not detected at an average concentration
greater than 10 times the minimum level of detection
(Flag=C) in the raw influent wastewater samples to a
treatment system.
(3) Pollutant not detected in most (Flag=F) raw influent
samples to a treatment system.
(4) Pollutants detected at low concentrations on all
sampling days (Flag=LC) or all targeted pollutants
detected at low concentration (Flag=LA) in the
raw influent to a treatment system.
(5) Metal type not processed on site (Flag=1).
(6) Metal type not present in raw wastewater because
of potential dilution from poor water-use practices
(Flag=2).
Assessment of treatment system performance:
(1) Treatment unit initially included in analysis, but upon
further research, technology was not an MP&M
technology option (Flag=O).
(2) Treatment system not operated at proper pH for
optimal removal of targeted metals (Flag=P).
(3) Poor removal of most targeted pollutants processed on
site, poor removal of solids, and/or effluent
concentrations that did not reflect BPT/BAT level of
performance (Flag=A).
Identification of process upsets on site during sampling
(Flag=V).
Identification of wastewater treatment chemicals (Flag=G).
LTA DATABASE
Contains treatment influent and effluent analytical
data from 58 sites collected during 63 sampling episodes,
including flags identified in preceding steps.
Figure 10-1. Summary of Technology Performance Data-Editing Procedures
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EPA flagged each data point failing an evaluation criterion and only included
unflagged effluent data points in the LTA and variability factor calculations. One pollutant at a
sampling point could have multiple flags, depending on the number of evaluation criteria it did
not meet. Where EPA conducted multiple episodes at one site, the Agency evaluated each
episode separately; therefore, EPA may have flagged a pollutant for a different reason for each
episode. Sections 10.2.1 through 10.2.4 describe the flags used in editing the database. Table
10-5 lists the number of effluent data points flagged for each technology option. The number of
flagged data points listed in this table reported only the initial flag for a pollutant. For example,
as shown in Table 10-5, EPA flagged 2,061 data points with a "N" flag. Of the remaining
unflagged points, the Agency flagged 453 with a "C" flag, then of the remaining unflagged data,
it flagged 10 with an F (see Figure 10-1 for a description of each flag).
Table 10-6A presents data from sampled facilities from all applicable
subcategories for total and amenable cyanide. Tables 10-6B through 10-6J present, for each
pollutant proposed for regulation and each subcategory, the daily effluent concentration for all
other data points that passed the data editing criteria. The Steel Forming and Finishing
Subcategory's mass-based limits are based on the General Metals Subcategory concentration
limits; therefore, data for both subcategories are presented together on Table 10-6B through
10-6J. Tables 10-6B only list data from sampled facilities within each subcategory. In
developing the proposed effluent limitations and standards, EPA, in certain cases, transferred
LTAs and variability factors from other subcategories (see Tables 10-8B through 10-8K).
10.2.1 Identification of Pollutants Not Present in the Raw Wastewater at Sufficient
Concentrations to Evaluate Treatment Effectiveness
EPA evaluated the concentrations of pollutants of concern in the influent to each
treatment system to determine which pollutants were present at concentrations high enough to
assess the treatment effectiveness of the system. EPA flagged the influent and corresponding
effluent data points for all specific pollutants in a treatment system that met the following
criteria:
1. EPA assigned a flag of "N" to a pollutant if EPA did not detect the
pollutant in any of the raw influent wastewater samples to a treatment
system during a sampling episode.
2. EPA assigned a flag of "C" to a pollutant if EPA did not detect the
pollutant in the raw influent wastewater to a treatment system at an
average concentration of greater than 10 times the minimum level of
detection during the sampling episode. The minimum level is the lowest
concentration that can be reliably measured by an analytical method. EPA
calculated the average influent concentration using the sample detection
limit when the pollutant was not detected in the influent.
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3. EPA assigned a flag of "F" to a pollutant if EPA detected the pollutant in
the raw influent to a treatment system at an average concentration greater
than 10 times the minimum level (see Step 2), but the Agency did not
detect the pollutant on most sampling days, and, when detected, EPA
detected it at a low concentration. EPA assigned this flag on a case-by-
case basis for each pollutant.
4. EPA assigned a flag of "LC" to a pollutant if EPA detected the pollutant in
the influent to a treatment system at an average concentration greater than
10 times the minimum level (see Step 2) but EPA did not detect the
pollutant on all sampling days at concentrations high enough to assess
treatment effectiveness. EPA assigned this flag on a case-by-case basis for
each pollutant.
5. EPA assigned a flag of "LA" on a case-by-case basis to all pollutants
associated with a treatment system if the concentrations of all the targeted
pollutants detected in the raw influent were not detected at high enough
concentrations to assess treatment effectiveness. EPA assigned this flag to
all effluent points associated with three episode-specific treatment units:
one ultrafiltration unit, one DAF unit, and one chemical precipitation with
microfiltration for clarification.
6. If a sampled site did not process a raw material associated with a pollutant
(e.g., cadmium or cyanide) then EPA assigned all unflagged data points for
that pollutant a flag of "1." EPA assigned this flag to specific pollutants at
effluent points associated with 14 chemical precipitation systems.
7. Because the proposed MP&M effluent limitations guidelines and standards
include water conservation practices and pollution prevention
technologies, EPA reviewed information obtained from sampled sites to
identify unit operations for which sites did not have water conservation
and pollution prevention technologies in place. EPA assigned a flag of "2"
to pollutants affected by poor water-use practices. If the poor water-use
practices only affected a specific pollutant (for example, a cadmium
electroplating line that did not have water conservation practices in place),
EPA assigned this flag only to the affected pollutant.
EPA assigned this flag to specific metals in the effluent data for seven
chemical precipitation systems and cyanide effluent data for one cyanide
destruction system. EPA also assigned this flag to all effluent data points
for a chemical precipitation system sampled during two episodes because
sampling personnel discovered that overflow rinses from metal finishing
operations flowed to the treatment system when the site discontinued
production, thus diluting the influent stream to the treatment system.
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10.2.2 Assessment of General Treatment System Performance
EPA assessed the performance of each sampled treatment system to identify well-
designed and well-operated systems. For this assessment, EPA first identified MP&M unit
operations performed on site to determine which pollutants (e.g., metals, cyanide, and oil and
grease) the site generated. EPA focused on these pollutants to assess treatment systems because
sites design systems to treat the specific pollutants generated on site. In some cases, complete
data on the types of pollutants generated at a site were unavailable because EPA toured only a
portion of the site. In these cases, EPA reviewed the concentrations of pollutants in the raw
wastewater to identify pollutants generated on site. EPA then performed the following technical
analyses of the treatment systems to determine which data would be included in the LTA
concentrations and variability factors.
1. EPA identified treatment systems that included technologies that were not
a part of EPA's technology options.
• EPA identified one chemical precipitation and sedimentation
system that included biological treatment and assigned an "O" flag
to all the effluent data associated with this treatment system.
• EPA identified a cyanide destruction system that added chlorine
gas for treatment and assigned an "O" flag to cyanide data for the
effluent associated with this treatment system.
2. EPA identified chemical precipitation and cyanide destruction systems that
the site did not operate at the optimum pH for treatment of the targeted
pollutants. The optimum pH for removal of metals by a chemical
precipitation system varies with the combination of metals processed at a
site; therefore, EPA based its evaluation of each chemical precipitation
system on the site-specific metals processed or treated.
• EPA assigned a flag of "P" to all effluent data associated with four
chemical precipitation and sedimentation systems identified as
operating outside pH ranges considered to be optimum for removal
of the site-specific targeted metals.
• EPA assigned flag of "P" to all amenable and total cyanide effluent
data associated with two cyanide destruction systems identified as
operating outside the optimum pH range for cyanide oxidation.
3. EPA identified treatment systems where the targeted pollutants present in
the influent did not decrease across the treatment system, the system had
poor removal efficiencies for targeted pollutants, or the effluent
concentrations for particular pollutants did not reflect BPT/BAT level of
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performance. Because pollutants targeted for removal depend on the
pollutants processed at a site and by the treatment technology, EPA
evaluated each treatment system separately, depending on the site
operations and treatment technology.
Chemical precipitation and sedimentation systems remove metals by
sedimentation of metal hydroxides in the form of suspended solids; poor
removal of total suspended solids (TSS) typically indicates poor removal
of metals in these systems. Therefore, in addition to analyzing for poor
metals removal, EPA identified chemical precipitation systems that did not
have good TSS removal.
• Of the unflagged data, EPA identified four chemical precipitation
systems with poor removal of targeted metals and assigned an "A"
flag to all effluent data associated with these systems.
• EPA assigned an "A" flag to amenable and total cyanide effluent
data for one cyanide destruction unit identified with poor cyanide
removal.
• EPA identified two chemical precipitation systems at two indirect
discharging facilities where the average copper and total suspended
solids effluent concentrations were greater than the current BPT
regulations for these pollutants under 40 CFR 433; therefore,
treatment was not indicative of BPT/BAT for direct dischargers.
EPA assigned an "A" flag for all copper and total suspended solids
data for these two sites.
• EPA identified two indirect discharging facilities where the
average total suspended solids effluent concentration in the
chemical precipitation system was greater than the current BPT
regulation for total suspended solids under 40 CFR 433; therefore,
treatment was not indicative of BPT/BAT for direct dischargers.
EPA assigned an "A" flag to effluent data for total suspended
solids for these treatment systems.
• EPA identified four oily waste facilities that were indirect
dischargers and were not required by their publicly owned
treatment works (POTW) to control oil and grease to BPT levels.
EPA assigned an "A" flag to the effluent data for oil and grease for
these four sites.
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10.2.3 Identification of Process Upsets That Could Affect Data Quality
EPA reviewed sampling episode reports and data for each sampling episode to
identify process upsets occurring on site that could impact treatment efficiency. In this review,
EPA also identified any sampling techniques that could affect the validity of analytical data.
EPA assigned a flag of "V" to affected pollutants on the days that a system could have been
impacted by a process upset or sampling technique. For example, if a process upset or poor
sampling technique only occurred on one day, EPA assigned only the data for that day a "V" flag,
or if a process upset or poor sampling technique affected only specific pollutants, EPA assigned
only the affected pollutants a "V" flag. Because a treatment system may have been sampled
during multiple sampling episodes and EPA evaluated each episode separately, the Agency may
have flagged a system or pollutant with a "V" during one episode but not for another episode.
Below are the results of this analysis.
• EPA identified a chemical precipitation system in which site personnel
used barrel finishing wastewater containing iron and aluminum as a
flocculation agent. During two sampling days, site personnel used a
different barrel finishing solution. On those days, the concentration of
metals in the effluent increased, indicating the new solution was not an
effective flocculation agent. EPA assigned a "V" flag to all effluent data
associated with the two sampling days when the site used the new
solution.
• EPA identified a chemical precipitation system in which the effluent
concentrations of copper were elevated and copper removal efficiencies
were lower than other metals treated by the system. The concentration of
cyanide in the influent system was also elevated compared to cyanide
concentrations typically seen at other MP&M facilities. These data
indicated that the site discharged some copper-cyanide chelates to the
system, affecting the system's ability to effectively precipitate copper.
EPA sampled this unit during multiple sampling episodes, and it assigned
a "V" flag to all effluent data for copper during these sampling episodes.
• EPA identified a chemical precipitation system where the effluent
concentrations of chromium were elevated compared to other metals
treated by the system. The site had a chromium reduction system that EPA
did not sample; however, based on data for hexavalent chromium in the
chemical precipitation system, EPA determined that the chromium
reduction system was not operating optimally during the sampling episode.
EPA assigned a "V" flag to the chromium data for this chemical
precipitation system.
• EPA identified a chemical precipitation system where the effluent
concentrations of nickel were elevated compared to other metals treated.
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EPA sampled this system during two sampling episodes. The elevated
nickel concentrations indicated that the batch chelation-breaking system
for electroless nickel rinses may not have been operating optimally. The
site combined the electroless nickel treatment sludges with other
wastewater prior to chemical precipitation. The liquid fraction of the
sludge likely contained chelated nickel, which then entered the chemical
precipitation system and could not be efficiently precipitated. EPA
assigned a "V" flag to all nickel effluent data for this treatment unit for
two sampling episodes.
EPA identified a cyanide destruction system where cyanide samples could
not be preserved until the end of the compositing period. Because some
degradation of cyanide may have occurred during this time, actual values
for cyanide may be higher than the measured value; therefore, EPA could
not accurately evaluate the data. EPA assigned a "V" flag to all cyanide
effluent data for this system during the sampling episode.
EPA identified a cyanide destruction system where the concentration of
cyanide and metals in the effluent were very high and comparable to those
seen in the influent to treatment systems. The data indicate that the
effluent samples may have been collected at an incorrect location so the
data could not be evaluated for this sampling episode. EPA assigned a
"V" flag to all cyanide effluent data for this system during the sampling
episode.
EPA identified a chemical oil-emulsion breaking system where site
personnel did not add oil-emulsion breaking polymer on one sampling day.
On this day, the concentration of oil and grease, total petroleum
hydrocarbons, and total suspended solids was higher in the effluent than
on the other sampling days, indicating that omission of the polymer may
have affected treatment on that day. EPA assigned a "V" flag to oil and
grease, total petroleum hydrocarbons, and total suspended solids effluent
data for that sampling day.
EPA identified an ultrafiltration system where the concentration of
chromium in the influent was significantly higher on one sampling day
than on the other days, and the concentration increased across the system.
These data indicated that the site had an unintended discharge of
chromium to the treatment system on that day at concentrations that were
too high for the system to effectively treat. EPA assigned a "V" flag to the
chromium data for the effluent on this sampling day.
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10.2.4 Identification of Wastewater Treatment Chemicals
EPA identified wastewater treatment chemicals used in each of the sampled
treatment systems. EPA assigned a flag of "G" to the treatment chemicals if they did not have
removals comparable to other metals on site, indicating a well-designed and well-operated
system. EPA assigned this flag to 194 effluent data points. Treatment chemicals typically
flagged included sodium, magnesium, aluminum, iron, and calcium. EPA flagged total dissolved
solids along with specific treatment chemicals, because the total dissolved solids concentration
generally increases as a result of treatment chemical addition.
10.3 Development of Long-Term Averages and Variability Factors
EPA used all unflagged data in the LTA Database to calculate the LTA
concentrations and variability factors that are the basis for the proposed effluent limitations and
standards. EPA calculated LTAs and variability factors from actual concentrations of
constituents measured in MP&M wastewater and treated by MP&M end-of-pipe technology
options (see Section 10.2). As described in Section 10.1, EPA sampling, industry trade
association sampling, and sanitation district sampling episodes at MP&M facilities provided the
data sets of daily effluent concentrations. The following sections discuss development of LTAs
and variability factors (VFs).
For each sampling episode, EPA calculated LTAs for all pollutants that had at
least one sample that passed the data editing review (Section 10.2). The Agency calculated the
LTA for each pollutant as the arithmetic average of the daily concentration values. For samples
where a pollutant was not detected in a sample, EPA used the sample detection limit to calculate
the LTA. EPA calculated the LTA for each pollutant for each subcategory by taking the median
value of the sampling episode LTAs for those episodes within each subcategory. EPA
transferred effluent data from one subcategory to another subcategory when sufficient data were
not available to calculate the limit for a specific pollutant within the original subcategory.
As discussed in Section 7.0, EPA is proposing a limitation for a Total Organics
Parameter (TOP). Table 10-7 lists the priority and nonconventional organics that are included as
part of this parameter. Section 10.4 presents EPA's methodology for calculating the proposed
TOP limitations. Table 10-8A presents LTAs and VFs for total and amenable cyanide for all
options for the applicable subcategories. Tables 10-8B through 10-8K show LTAs and VFs for
each pollutant for each technology option in each subcategory. Tables 10-9A through 10-9J list
the LTAs, VFs, and limitations for each subcategory.
10.3.1 Derivation of the Proposed Limitations
The limitations and standards are the result of multiplying the LTAs by the
appropriate variability factors. The same basic procedures apply to the calculation of all
limitations and standards for this industry, regardless of whether the technology is BPT, BCT,
BAT, NSPS, PSES or PSNS.
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The limitations for pollutants for each option are provided as 'daily maximums'
and 'maximums for monthly averages.' Definitions provided in 40 CFR 122.2 state that the daily
maximum limitation is the "highest allowable 'daily discharge'" and the maximum for monthly
average limitation (also referred to as the "monthly average limitation") is the "highest allowable
average of 'daily discharges' over a calendar month, calculated as the sum of all 'daily
discharges' measured during a calendar month divided by the number of 'daily discharges'
measured during that month." EPA defines daily discharges as the '"discharge of a pollutant'
measured during a calendar day or any 24-hour period that reasonably represents the calendar day
for purposes of samplings."
EPA calculates the limitations based upon percentiles that reflect both the
variability within control of the facility and a level of performance consistent with the Clean
Water Act requirement that these effluent limitations be based on the "best" technologies. The
daily maximum limitation is an estimate of the 99th percentile of the distribution of the daily
measurements. The monthly average limitation is an estimate of the 95th percentile of the
distribution of the monthly averages of the daily measurements.
In establishing daily maximum limitations, EPA's objective is to restrict the
discharges on a daily basis at a level that is achievable for a facility that targets its (well-operated
and well designed) treatment at the long-term average. EPA acknowledges that variability
around the long-term average results from normal operations. This variability means that
occasionally facilities may discharge at a level that is greater than the long-term average. This
variability also means that facilities may occasionally discharge at a level that is considerably
lower than the long-term average. To allow for these possibly higher daily discharges, EPA has
established the daily maximum limitation. A facility that discharges consistently at a level near
the daily maximum limitation would not be operating its treatment to achieve the long-term
average which is part of EPA's objective in establishing the daily maximum limitations.
In establishing monthly average limitations, EPA's objective is to provide an
additional restriction that supports EPA's objective of having facilities target their average
discharges to achieve the long-term average. The monthly average limitation requires continuous
dischargers to provide on-going control, on a monthly basis, that complements controls imposed
by the daily maximum limitation. To meet the monthly average limitation, a facility must
counterbalance a value near the daily maximum limitation with one or more values well below
the daily maximum limitation. To achieve compliance, these values must result in a monthly
average value at or below the monthly average limitation.
In the first of two steps in estimating both types of limitations, EPA determines an
average performance level (the "long-term average" discussed in Section 10.3.4) that a facility
with well-designed and operated model technologies (which reflect the appropriate level of
control) is capable of achieving. This long-term average is calculated from the data from the
facilities using the model technologies for the option. EPA expects that all facilities subject to
the limitations will design and operate their treatment systems to achieve the long-term average
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performance level on a consistent basis because facilities with well-designed and operated model
technologies have demonstrated that this can be done.
In the second step of developing a limitation, EPA determines an allowance for
the variation in pollutant concentrations when processed through extensive and well designed
treatment systems. This allowance for variance incorporates all components of variability
including treatment process sampling and analytical variability. This allowance is incorporated
into the limitations through the use of the variability factors (discussed in Section 10.3.5) which
are calculated from the data from the facilities using the model technologies. If a facility
operates its treatment system to meet the relevant long-term average, EPA expects the facility to
be able to meet the limitations. Variability factors assure that normal fluctuations in a facility's
treatment are accounted for in the limitations. By accounting for these reasonable excursions
above the long-term average, EPA's use of variability factors results in limitations that are
generally well above the actual long-term averages.
Tables 10-9A through 10-9J present the limitations.
10.3.2 Steps Used to Derive Concentration-Based Limitations
The derivation of the concentration-based daily and monthly maximum
limitations uses the pollutant-specific LTAs and respective VFs. The following steps are used to
derive the concentration-based limitations.
Step 1: Calculate the facility-specific LTAs and 1-day and 4-day VFs for all facilities.
Calculation of VFs is performed when the facility has four or more observations
with two or more distinct detected values.
Step 2: For each option in the subcategory, calculate the median of the facility-specific
LTAs and the mean of the facility-specific 1-day and 4-day VFs to provide
pollutant-specific LTAs and 1-day and 4-day VFs.
Step 3: Calculate the daily limitations for a pollutant using the product of the pollutant-
specific LTA and the pollutant-specific 1-day VF. Calculate monthly average
limitations using the product of the pollutant-specific LTA and the pollutant-
specific 4-day VF.
10.3.3 Modified Delta-Lognormal Model
EPA selected the modified delta-lognormal distribution to model pollutant
effluent concentrations from the MP&M industry in developing the variability factors. A typical
effluent data set from a facility in this industry consists of a mixture of measured (detected) and
nondetected values. Within a data set, gaps between the values of detected measurements and
the sample-specific detection limits associated with nondetected measurements may indicate that
different pollutants were present in the different industrial wastes treated by a facility.
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Nondetected measurements may indicate that the pollutant is not generated by a particular source
or industrial process. The modified delta-lognormal distribution is appropriate for such data sets
because it models the data as a mixture of measurements that follow a lognormal distribution and
nondetect measurements that occur with a certain probability. The generalized form of the model
also allows for the possibility that nondetect measurements occur at multiple sample- specific
detection limits. Because the data appear to fit the modified delta-lognormal model reasonably
well, EPA believes this model is an appropriate model for the MP&M industry data.
The modified delta-lognormal distribution is a modification of the 'delta
distribution' originally developed by Aitchison and Brown1. The resulting mixed distributional
model, which combines a continuous density portion with a discrete-valued spike at zero, is also
known as the delta-lognormal distribution. The delta in the name refers to the proportion of the
overall distribution contained in the discrete distributional spike at zero, that is, the proportion of
zero amounts. The remaining non-zero, non-censored (NC) values are grouped together and fit
to a lognormal distribution.
EPA modified this delta-lognormal distribution to incorporate multiple detection
limits. In the modification of the delta portion, the single spike located at zero is replaced by a
discrete distribution made up of multiple spikes. Each spike in this modification is associated
with a distinct sample-specific detection limit associated with nondetected (ND) measurements
in the database. A lognormal density is used to represent the set of measured values. Figure 10-2
shows this modification of the delta-lognormal distribution.
Detects
0 5101520
Figure 10-2. Modified Delta-Lognormal Model
In the modified model, • represents the proportion of NDs, but is divided into the sum of smaller
fractions, •;, each representing the proportion of NDs associated with a particular and distinct
detection limit. Thus it is written as
'Aitchison, J. and Brown, J.A.C. (1963) The Lognormal Distribution. Cambridge University Press, pages 87-99.
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If D; equals the value of the ith smallest distinct detection limit in the data set, and the random
variable XD represents a randomly chosen ND sample, then the discrete distribution portion of
the modified delta-lognormal model is mathematically expressed as
EPA uses the following formulas to calculate the mean and variance of this discrete distribution:
Var(XD) = -L]
10.3.4 Estimation Under the Modified Delta-Lognormal Model
A wide variety of observed effluent data sets fit the modified model. The model
also handles multiple detection limits for NDs. The same basic framework is used even if there
are no ND values or censored data.
U is the modified delta lognormal random variable which combines the discrete
portion of the model with the continuous portion. The following equation expresses the
cumulative probability distribution of the modified delta-lognormal model, where Dk denotes the
largest distinct detection limit observed among the NDs and the first summation is taken over all
those values, D:, that are less than u.
Pr(U [(log(M) - n)/o)] if
(10-4)
Again combining the discrete and continuous portions of the modified model, the
expected value of the random variable U is derived as a weighted sum of the expected values of
the discrete and continuous lognormal portions of the distribution. This follows because the
modified delta-lognormal random variable U is expressed again as a combination of three other
independent variables, that is,
U = IUXD + (\-Iu)Xc (10-5)
where this time XD represents a random ND from the discrete portion of the model, Xc represents
a random detected measurement from the continuous lognormal portion, and Iu is an indicator
10-16
-------
10.0 - Long-Term Averages and Variability Factors
variable signaling whether any particular random measurement is detected or not. Then the
expected value and variance of U have the form
E(U) = £ 6.Z). + (1 - 6)expOi + 0.5o2) (10_6)
Var(U) = -^LJ + (1 - 6)exp(2|i + o2)(exp(o2) - 1)
6
6(1-6)
2 (1°-7)
6
0.5o2)
where D; = detection limit for the ith smallest ND value
Dj = detection limit for the jth smallest ND value, where i < j
• ; = proportion of NDs with detection limit = D;
• j = proportion of NDs with detection limit = Dj
• = proportion of all NDs
• = mean log concentrations of NC values
• = standard deviation of log NC values.
10.3.5 Estimation of LTAs and VFs (Data Groups)
To estimate facility-specific long-term averages (LTAs) and variability factors
(VFs), EPA divided the MP&M data sets into two groups based on their size (number of
samples) and the type of samples in the subset because the computations differ for each group.
EPA defined the groups as follows:
Group 1: Less than 2 NC (detectable) samples or less than 4 total samples at
a facility. Specifically, Group 1 contains all data subsets with all
NDs or only one detect. Sample-specific detection limits are
substituted as the values associated with nondetected pollutants.
Group 2: Two or more NC (detectable) samples and 4 or more total samples.
Sample-specific detection limits are substituted as the values
associated with nondetected pollutants.
10.3.6 Estimation of LTAs
EPA first calculated facility-specific LTAs as the arithmetic average of the
samples using data from Groups 1 and 2. EPA then derived pollutant-specific LTAs from the
10-17
-------
10.0 - Long-Term Averages and Variability Factors
facility-specific LTAs. Pollutant-specific LTAs provide one concentration for a specific
pollutant for all facilities within a subcategory and option.
Within each subcategory and option combination, EPA calculated pollutant-
specific LTAs as the median of the facility-specific LTAs for that pollutant. The median is the
midpoint of the values ordered (i.e., ranked) from smallest to largest. If there is an odd number
of values (with n=number of values), then the value of the (n+l)/2 ordered observation is the
median. If there is an even number of values, then the two values of the n/2 and [(n/2)+l]
ordered observations are arithmetically averaged to obtain the median value.
10.3.7 Estimation of VFs
EPA developed 1-day and 4-day facility-specific VFs for all regulated pollutants
using Group 2 data only. EPA did not use Group 1 data to estimate VFs because the data were
insufficient for estimating variability using the modified delta-lognormal methodology.
For Group 2, EPA calculated the parameters for the lognormal portion of the data
using maximum likelihood estimation in the log-domain. Upper percentiles and VFs are
calculated using these estimated parameters. Calculation of these VFs is described in Section
10.3.7.1 and 10.3.7.2.
10.3.7.1 Estimation of 1-day VFs
The 1-day facility-specific VFs are a function of the facility-specific LTA and the
99th percentile. The 99th percentile of each data subset is calculated using the modified delta-
lognormal methodology by first defining D0=0, • 0=0, and Dk+1 = • as boundary conditions,
where D; equals the ith smallest detection limit, and •; is the associated proportion of NDs at the
ith detection limit. A cumulative distribution function, p, for each data subset is computed as a
function ranging from 0 to 1. The general form for p, for a given value c, is
p = P(U < c) =
log(c) k n , „ <, n m=c\ 1 j. nO-8)
where
t=i ' (10-9)
5
n
10-18
-------
10.0 - Long-Term Averages and Variability Factors
(10-10)
and • is the standard normal cumulative distribution function. EPA calculated the estimated 99th
percentile of each data subset as follows:
1. k values of p at c=Dm, m=l,...k are computed and labeled pm.
2. The smallest value of m, such that pm • 0.99, is determined and labeled as
Pj. If no such m exists, steps 3 and 4 are skipped and step 5 is computed
instead.
3. p* = PJ - • j is computed.
4. If p*< 0.99, then P99 = Dj,
elseifp** 0.99, then
,-1
^ \
0.99-£,6J
(1-6)
(10-11)
5. If no such m exists, such that pm • 0.99 (m=l,...k), then
(1 +
,-1
0.99 - 6
o
The daily VF, VF1, is then calculated as
VF1 =
99
E(U)
(10-12)
(10-13)
where
(l-6)exp(|l+0.5d2).
A pollutant-specific 1-day VF is the mean of the facility-specific daily VFs for
that pollutant in the subcategory and option combination.
10-19
-------
10.0 - Long-Term Averages and Variability Factors
10.3.7.2 Estimation of 4-day VFs
EPA calculated a facility-specific VF for monthly averages based on the
distribution of 4-day averages. To calculate the 4-day facility-specific VF, EPA assumed that the
approximating distribution of • 4, the sample mean for a random sample of four independent
concentration values, also is derived from this modified delta-lognormal distribution with the
same mean as the distribution of the concentration values. The mean of this distribution of 4-day
averages is
E(U4) = 64£(14)Z) + (l-64)£(!4)c (10-14)
where E(X4)D denotes the mean of the discrete portion of the distribution of the average of four
independent concentration values (i.e., when all observations are not detected), and E(X4)C
denotes the mean of the continuous lognormal portion of the distribution.
First, EPA assumed that the probability of nondetection (• ) on each of the four
days is independent of that on the other days, and the nondetected values are therefore not
correlated; consequently, • 4 = •4. Also, because
- E(XD)
then
E(U4) = 842^ -!—!• + (1 -64)exp(n4 + 0.5o24) (10-15)
t=\ 8
and since £(• 4) = E(U), then
1=1
-5^, -°-5^
The expression for • 24 is derived from the following relationship:
i + 84(1-84)[JE(X4)Z)-JE:(X4)C]2. (10-17)
Because
Var((X4)D) = -1, E(XJD = E(XJ, and 64 = 64 (10-18)
then
10-20
-------
10.0 - Long-Term Averages and Variability Factors
64(1 -
(10-19)
This further simplifies to
84(1 - 64)
462
t^
-84)exp(2ki4 + o24)[exp(o24)
12
(10-20)
i=\
6
- exp(|i4 + 0.5a24)
and furthermore,
- 62(1 - 64)
exp(o24)-l =
Then, from (10-15) above,
1=1
>.-8exp(|i4 + 0.5o24)
- 64)exp(2ki4 + o24)
- 64)
(1-64)
-, because £(£/4) =
(10-21)
(10-22)
and letting
r\ -
then, exp(|i4 + 0.5a24) = —3_—. (10-23)
(1-84)
Furthermore,
024 - log
1 +
-82(l-64)
' C1-64),
42
- 84)
(10-24)
10-21
-------
Since Var(» 4) = Var(U)/4, then, by rearranging terms,
024 = log
4T1
4if
10.0 - Long-Term Averages and Variability Factors
1=1
(10-25)
Thus, estimates of • 4 and • 4 are derived by using estimates of • lv..» k (sample proportion of NDs
at observed detection limits Dlv..Dk), • (maximum likelihood estimate (MLE) of logged values),
and • 2 (MLE logvariance multiplied by
above.
to reflect estimation from sample) in the equations
To find the estimated 95th percentile of the average of four observations, four
NDs, not all at the same detection limit, an average is generated that is not necessarily equal to
Dl3 D2,..., or Dk. Consequently, more than k discrete points exist in the distribution of the 4-day
averages. For example, the average of four NDs at k=2 detection limits are at the following
discrete points with the associated probabilities:
1
2
3
4
5
D
(D1+3D2)/4
6*
(3Z)!+Z)2)/4 46 ^6.
In general, when all four observations are not detected, and when k detection
limits exist, the multinomial distribution is used to determine associated probabilities; that is,
Pr
^4 =
4!
-136"'.
(10-26)
where u; is the number of nondetected measurements in the data set with the D; detection limit.
The number of possible discrete points, k*, for k= 1,2,3,4, and 5 are given below:
k
1
2
3
4
5
k
1
5
15
35
70
10-22
-------
10.0 - Long-Term Averages and Variability Factors
To find the estimated 95th percentile of the distribution of the average of four
observations, the same basic steps (described in Section 10.3.7.1) as used for the 99th percentile
of the distribution of daily observations are followed, with the following changes:
1. Change P99 to P95, and 0.99 to 0.95.
2. Change Dm to Dm*, the weighted averages of the detection limits.
3. Change •; to • ;*.
4. Change k to k*, the number of possible discrete points based on k detection
limits.
5. Change the estimates of •, •, and • to estimates of •4, • 4, and • 4,
respectively.
Then, the estimate of the 95th percentile 4-day facility-specific mean VF is:
As
VF4 = ——. (10-27)
E(U)
A pollutant-specific 4-day VF is the mean of the facility-specific 4-day VFs for that pollutant in
the subcategory and option combination.
10.4 Methodology for Development of TOP Long-Term Averages and Variability
Factors
EPA used the following steps to calculate the LTAs and VFs for the Total Organic
Parameter:
• Determine the LTA for each organic component;
• Sum the component LTAs;
• Multiply the total LTA by the mean VF across the individual organic
components; and
• Add the sum of nominal quantitation limits for top pollutants that are not
in the LTA database.
Table 10-7 lists the nominal quantitation values for all of the TOP pollutants and
indicates which TOP pollutants EPA had sufficient data for in its LTA database to calculate an
LTA. For those without data in the LTA database, EPA used the nominal quantitation limit in
calculating the TOP limits. See the Statistical Support Document for Proposed Effluent
Limitations Guidelines and Standards for the Metal Products and Machinery Industry for more
information on the statistical procedures used to develop the TOP limitations.
10-23
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-1
Number of Evaluated Treatment Systems for Each Subcategory
MP&M End-of-Pipe Technology Option
Cyanide destruction (applies to all subcategories where cyanide is a regulated
pollutant)
Number of Treatment Units
13
General Metals Subcategory
Chemical precipitation and clarification using sedimentation (Option 2)
Chemical precipitation and clarification using membrane filtration (Option 4)
29
4
Metal Finishing Job Shop Subcategory
Chemical precipitation and clarification using sedimentation (Option 2)
6
Printed Wiring Boards Subcategory
Chemical precipitation and clarification using sedimentation (Option 2)
Chemical precipitation and clarification using membrane filtration (Option 4)
2
1
Shipbuilding Drydock Subcategory
DAF
o
6
Oily Wastes Subcategory
Chemical emulsion breaking and oil-water separation (Option 2)
5
Railroad Line Maintenance Subcategory
DAF (Option 2)
1
Nonchromium Anodizing Subcategory
Chemical precipitation and clarification using sedimentation (Option 2)
2
Source: MP&M LTA Database.
10-24
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-2
Influent and Effluent Data Points from EPA Sampling Episodes
MP&M End-of-Pipe
Technology Option
Chemical precipitation and
clarification using
sedimentation
Chemical precipitation and
clarification using membrane
filtration
Ultrafiltration
DAF
Chemical emulsion breaking and
oil-water separation
Cyanide destruction
Total
Number of Sites3
39
5
15
2
5
17
53
Number of
Sampling
Episodes3
42
5
15
3
5
19
57
Number of
Treatment
Units
42
5
16
2
5
17
87
Number of
Data Points"
62,892
12,824
28,150
4,872
11,926
218
120,882
aEPA conducted multiple sampling episodes at some sites and sampled multiple treatment units at some sites;
therefore, the total does not equal the sum of a column.
bThe database contains 137,823 influent and effluent data points from EPA sampling episodes. For cyanide
destruction, EPA included only data points for amenable and total cyanide in the LTA analysis (to calculate LTAs,
the Agency did not use 16,843 data points associated with analytes other than cyanide across cyanide destruction
treatment units). EPA used data points for organic, metal, conventional, and nonconventional pollutants in the LTA
analysis for treatment units other than cyanide destruction; however, it did not include cyanide (total and amenable)
in the analysis for these other treatment units (98 data points associated with cyanide data across treatment units not
designed for cyanide destruction were not evaluated).
Source: MP&M LTA Database.
10-25
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-3
Influent and Effluent Data Points from Industry and
Local Sanitation District Sampling Episodes
MP&M End-of-Pipe Technology Option
Chemical precipitation and clarification using
sedimentation
DAF
Cyanide destruction
Total
Number of
Sites3
3
2
4
5
Number of
Sampling
Episodes3
4
2
5
6
Number of
Treatment
Units
3
2
4
9
Number of
Data
Points"
1,752
2,759
83
4,594
Sanitation districts conducted multiple episodes at some sites and sampled multiple treatment units at some sites;
therefore, the total does not equal the sum of a column.
bThe database contains 6,616 influent and effluent data points from industry and local sanitation district sampling.
For cyanide destruction, EPA included only data points for amenable and total cyanide in the LTA analysis;
therefore, to calculate LTAs, it did not use 2,022 data points associated with analytes other than cyanide cross
cyanide destruction treatment units. EPA used data points for organic, metal, conventional, and nonconventional
pollutants in the LTA analysis for all treatment units other than cyanide destruction; however, it did not include
cyanide (total and amenable) in the analysis for these other treatment units.
Source: MP&M LTA Database.
Table 10-4
Industry-Supplied Effluent Monitoring Data
Treatment Type
Chemical precipitation and clarification
using sedimentation
Chemical precipitation and clarification
using membrane filtration
Ultrafiltration
DAF for oily waste streams
Chemical oil-emulsion breaking
Cyanide destruction
Number of Sites
5
o
J
2
2
1
3
Number of
Treatment Units
5
3
2
2
1
3
Number of Effluent
Data Points
2,505
708
393
439
355
109
Source: MP&M LTA Database.
10-26
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-5
Number of Effluent Data Points Flagged for Each MP&M Technology Option
MP&M End-of-Pipe
Technology Option
Chemical Precipitation with
Membrane Filtration
Chemical Precipitation with
Sedimentation
Cyanide Destruction
Ultrafiltration
Chemical Emulsion
Breaking and Oil/Water
Separation
DAF
Total
Number of
Effluent Data
Points Evaluated a
2,856
15,743
151
6,442
2,626
1,754
29,572
Number of Flagged Effluent Data Points
N
2,061
9,091
2
3,828
1,492
1,013
17,487
C
453
3,665
19
1,044
519
444
6,144
F
10
36
0
8
25
6
85
LC
35
259
4
163
51
25
537
LA
12
0
0
35
0
10
57
1
0
147
0
0
0
0
147
2
0
109
5
0
8
0
122
O
0
33
1
0
0
0
34
P
0
155
10
0
0
0
165
A
10
178
1
0
14
0
203
V
0
40
13
1
3
0
57
G
55
309
0
0
47
29
440
Number of
Unflagged
Effluent Data
Points
220
1,721
96
1,363
475
227
4,102
10-27
a EPA only evaluated data for pollutants of concern. Data for cyanide destruction units are for amenable and total cyanide only. Data points for treatment units (other than cyanide
destruction) are for priority metals and organics, nonconventional metals and organics, and conventional and nonconventional pollutant parameters, and exclude cyanide data.
Section 7.0 lists the pollutants of concern.
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6A
MP&M Technology Effectiveness Concentrations for
Total and Amenable Cyanide Destruction3
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Total Cyanide
4274
4279
4384
4460A
4807
4817
4828
4834
4847
4891
4904
6048
6186
CBI
9.9
CBI
—
—
345
—
CBI
0.024
CBI
6.33
7.38
97.7
Day 2
Day 3
CBI
7.6
CBI
21.1
0.077
368
—
CBI
2.3
CBI
12.70
9.72
66.2
CBI
11.0
CBI
—
47.8
371
8.64
CBI
0.026
CBI
6.80
6.59
69.0
Day 4
Day 5
CBI
50.0
CBI
—
4.25
394
17.9
CBI
0.01
CBI
10.90
5.14
75.3
CBI
48.0
CBI
—
0.094
—
2.99
CBI
3.22
CBI
7.29
10.40
102.0
Amenable Cyanide
4807
4817
4828
4834
4847
4904
6048
6186
—
345
—
CBI
0.01
6.33
6.96
97.4
0.077
368
—
CBI
2.21
12.50
9.21
65.7
47.7
371
8.62
CBI
0.03
6.53
6.13
68.5
4.25
394
17.40
CBI
0.01
10.30
4.87
74.8
0.02
—
2.91
CBI
3.15
4.43
9.60
102.0
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
0.01
0.01
0.99
—
0.021
0.58
0.062
0.02
—
0.056
0.175
0.17
0.13
0.01
0.01
0.69
0.02
0.028
0.81
0.180
0.02
0.019
0.110
0.117
0.30
0.20
Day 3
Day 4
Day 5
0.01
0.01
0.76
—
0.047
0.20
0.092
0.02
0.010
0.044
0.325
0.19
0.21
—
0.01
0.94
—
0.020
0.61
0.076
0.02
0.010
0.071
0.309
0.17
0.24
—
0.01
0.46
—
0.020
0.02
0.049
0.02
0.010
0.160
0.359
0.20
0.20
0.02
0.58
0.035
0.02
—
0.162
0.02
0.049
0.02
0.81
0.160
0.02
0.01
0.073
0.037
0.022
0.02
0.20
0.063
0.02
0.01
0.143
0.005
0.017
0.02
0.58
0.038
0.02
0.01
0.134
0.005
0.110
0.02
—
0.024
0.02
0.01
0.082
0.014
0.110
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
— No samples collected on this day.
CBI - Confidential Business Information.
10-28
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6B
MP&M Technology Effectiveness Concentrations for
General Metals and Steel Forming and Finishing Subcategories (Option 2)a'b
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Oil and Grease
4737
4871
CBI
114.0
CBI
53.1
CBI
39.9
CBI
92.0
CBI
37.4
Total Suspended Solids (TSS)
11 97 A
4011
4079
4277
4384
4415
4417
4438
4470
4737
4761
4762
4807
4811
4817
4833
4834
4871
4904
12
CBI
CBI
320
CBI
—
430
410
CBI
CBI
CBI
CBI
172
CBI
46
115
CBI
724
6230
54
CBI
CBI
20
CBI
77.1
70
—
CBI
CBI
CBI
CBI
150
CBI
14
150
CBI
538
8080
260
CBI
CBI
11
CBI
119.0
32
—
CBI
CBI
CBI
CBI
144
CBI
66
129
CBI
193
8920
—
CBI
CBI
13
CBI
130.6
22
10
CBI
CBI
CBI
CBI
124
CBI
108
244
CBI
647
7520
—
CBI
CBI
16
CBI
—
4
11
CBI
CBI
CBI
CBI
124
CBI
61
230
CBI
258
6240
Manganese
4762
4807
4871
4904
CBI
0.446
8.67
3.53
CBI
0.358
7.83
6.11
CBI
0.469
3.97
5.20
CBI
1.60
10.10
5.69
CBI
1.31
5.49
4.33
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
14.4
6.02
16.5
6.22
14.1
6.17
10.0
6.12
13.0
6.15
28.0
28.0
9.0
14.0
50.0
—
12.0
7.0
14.5
20.0
17.0
14.0
6.0
4.0
8.0
6.5
4
7
4.5
20.0
30.0
5.0
14.0
32.0
1.0
10.0
—
10.0
14.5
24.0
16.0
16.0
4.0
4.0
7.0
14
8
4.0
32.0
22.0
5.0
17.0
55.0
1.0
7.0
—
10.0
35.0
25.0
13.0
7.5
4.0
21.0
17.5
4
6
4.0
—
—
—
10.0
23.0
1.0
4.0
8.0
22.0
12.5
—
16.0
8.0
4.0
18.0
5.5
44
4
8.5
—
—
—
17.0
68.0
—
2.0
5.0
32.0
38.0
—
13.0
4.0
4.0
8.0
5.5
7
4
7.5
0.168
0.030
0.103
0.0144
0.165
0.047
0.104
0.0209
0.097
0.040
0.088
0.0132
0.130
0.071
0.076
0.0079
0.134
0.061
0.087
0.0097
10-29
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6B (Continued)
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Molybdenum
4806
4904
1.15
0.634
1.15
1.28
1.27
1.39
0.592
1.5
1.16| 1.44
0.942| 0.028
0.639
0.034
0.501
0.036
0.665
0.031
0.371
0.027
Tin
4817
4834
6.33
CBI
4.65
CBI
5.17
CBI
13.9
CBI
6.92| 0.034
CBl|| 0.59
0.030
0.57
0.028
0.72
0.086
1.37
0.122
0.82
Total Organic Carbon (TOC) (as indicator parameter)
4737
4761
4762
4806
4807
4817
4833
4834
4871
4904
CBI
CBI
CBI
8.26
20.2
29.6
26
CBI
174
10
CBI
CBI
CBI
12.9
26.3
29.6
41
CBI
102
24
CBI
CBI
CBI
13.8
17.4
51.3
73
CBI
149
10
CBI
CBI
CBI
12.5
17.3
57.4
10
CBI
206
10
CBI
CBI
CBI
27.9
24.1
47.3
22
CBI
124
18
75
52
172
29.3
16.2
16.4
10
87.1
117
10
106
46
180
12.9
23.6
17.4
12
77.9
87
10
71
51
147
9.3
27.4
21.6
34
90.7
117
10
108
—
182
37.0
10.2
25.7
10
67.6
91
10
71
—
172
20.4
8.91
31.7
10
42
101
10
Cadmium
11 97 A
4277
4415
4460
6048
—
18.9
—
0.068
13.9
1.49
3.42
0.443
0.347
21.6
0.271
0.903
0.0358
0.141
8.50
—
2.93
0.0483
—
6.56
—
5.27
—
—
6.73
—
0.230
—
0.021
0.857
0.08
0.202
0.005
0.049
1.09
0.06
0.0779
0.005
0.035
0.942
—
0.140
0.005
—
0.765
—
0.219
—
—
0.801
Chromium
11 97 A
4011
4079
4310
4330
4384
4415
4417
28.7
CBI
CBI
CBI
CBI
CBI
—
5.10
1.4
CBI
CBI
CBI
CBI
CBI
5.303
3.31
0.027
CBI
CBI
CBI
CBI
CBI
1.475
3.56
—
CBI
CBI
CBI
CBI
CBI
0.973
2.77
—
CBI
CBI
CBI
CBI
CBI
—
1.57
1.23
0.756
0.635
0.395
0.066
0.593
—
0.0199
0.656
0.726
1.82
1.77
0.131
0.603
0.015
0.0133
0.027
1.13
0.456
4.65
0.043
0.785
0.020
0.0292
—
—
—
—
0.050
0.411
0.112
0.0098
—
—
—
—
0.043
0.532
—
0.0216
10-30
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6B (Continued)
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Chromium (continued)
4438
4460
4470
4811
4817
4833
4847
4871
4904
28.1
4.24
CBI
CBI
2.73
8.85
8.32
1.54
7.7
—
8.8
CBI
CBI
2.55
19.1
8.07
0.82
12.1
—
3.06
CBI
CBI
2.15
18.1
28.7
0.41
15.6
17.4
—
CBI
CBI
0.33
62.2
10.0
1.57
14.8
19.3
—
CBI
CBI
1.64
37.4
102
0.515
11.0
0.099
1.33
0.0825
0.008
0.0576
0.0369
0.380
0.01
0.017
—
1.21
0.0555
0.008
0.314
0.0281
0.201
0.01
0.012
—
0.984
0.0686
0.008
0.0805
0.0675
0.194
0.01
0.011
0.091
—
0.1083
0.010
0.0217
0.0891
0.190
0.01
0.022
0.088
—
0.0716
0.009
0.2715
0.118
0.543
0.01
0.012
Copper
4277
4737
4806
4807
4817
4833
4834
4847
4904
29.50
CBI
13.6
29.5
32.8
0.402
CBI
1.65
157
7.74
CBI
8.57
27.7
30.0
1.48
CBI
2.43
251
5.16
CBI
8.18
23.0
32.6
2.91
CBI
3.57
251
13.1
CBI
4.47
22.4
36.8
3.70
CBI
0.944
273
14.6
CBI
1.66
23.5
30.1
2.63
CBI
1.03
224
0.638
0.507
1.07
1.31
0.199
0.110
0.0519
0.118
0.037
0.701
0.235
0.265
1.43
0.149
0.127
0.0454
0.100
0.040
0.610
0.022
0.301
1.36
0.154
0.098
0.0477
0.103
0.031
0.462
0.040
0.926
0.71
0.260
0.131
0.0772
0.035
0.049
0.385
0.073
0.484
0.426
0.428
0.175
0.0796
0.046
0.073
Lead
11 97 A
4761
4762
4834
4871
0.20
CBI
CBI
CBI
1.47
0.223
CBI
CBI
CBI
1.95
159
CBI
CBI
CBI
1.04
—
CBI
CBI
CBI
1.80
—
CBI
CBI
CBI
1.12
0.47
0.012
0.0248
0.0256
0.0087
4.97
0.012
0.0248
0.016
0.0130
0.20
0.012
0.0248
0.0181
0.011
—
—
0.0248
0.0186
0.0061
—
—
0.0248
0.0244
0.0083
Nickel
11 97 A
4277
4438
4470
4761
4762
4807
0.082
27.4
34.2
CBI
CBI
CBI
6.56
6.29
2.705
—
CBI
CBI
CBI
5.73
0.071
1.05
—
CBI
CBI
CBI
6.67
—
3.54
32.4
CBI
CBI
CBI
6.90
—
6.38
31.7
CBI
CBI
CBI
5.95
0.209
0.173
0.378
0.339
0.319
0.304
0.287
1.390
0.180
—
0.229
0.254
0.232
0.354
1.390
0.161
—
0.143
0.225
0.124
0.319
—
0.180
0.518
0.222
—
0.158
0.220
—
0.197
0.348
0.224
—
0.211
0.138
10-31
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6B (Continued)
Episode
4811
Daily Influent Concentration
(mg/L, ppm)
Dayl
CBI
Day 2
CBI
Day 3
CBI
Day 4
CBI
Day5
CBI
Daily Effluent Concentration
(mg/L, ppm)
Dayl
0.0160
Day 2
0.057
Day 3
0.063
Day 4
0.018
Day5
0.037
Nickel (continued)
4817
4833
4834
4847
4871
4904
6048
0.209
0.507
CBI
0.639
8.97
6.60
0.718
0.329
0.651
CBI
0.918
8.48
11.4
22.4
0.721
0.724
CBI
2.64
4.70
10.8
4.56
0.944
0.864
CBI
1.52
10.3
12.4
8.95
1.38
5.02
CBI
0.43
6.11
8.99
21.2
0.0209
0.192
0.212
0.043
0.697
0.026
0.135
0.0284
0.016
0.216
0.031
0.620
0.026
0.518
0.0282
0.016
0.310
0.027
0.602
0.026
0.270
0.0472
0.016
0.430
0.061
0.536
0.026
0.284
0.0473
0.016
0.484
0.110
0.802
0.026
0.525
Silver
11 97 A
4277
4807
4817
0.005
4.230
0.999
0.910
3.2
0.138
1.670
0.793
0.029
0.0165
1.010
1.040
—
0.121
0.683
0.946
—
0.303
0.923
0.548
0.559
0.005
0.0202
0.0160
0.430
0.005
0.0472
0.0782
0.029
0.010
0.0701
0.051
—
0.005
0.0006
0.0613
—
0.027
0.0218
0.1025
Zinc
11 97 A
4277
4415
4417
4470
4737
4761
4762
4807
4811
4817
4871
4904
—
3.48
—
142
CBI
CBI
CBI
CBI
4.13
CBI
57.6
32
3.91
0.153
1.335
2.303
66.1
CBI
CBI
CBI
CBI
3.97
CBI
55.5
25.7
6.21
0.062
0.925
1.923
45.9
CBI
CBI
CBI
CBI
4.19
CBI
30.6
13
4.62
—
0.801
3.012
4.55
CBI
CBI
CBI
CBI
3.56
CBI
51.5
34.9
4.21
—
2.64
—
19.9
CBI
CBI
CBI
CBI
3.02
CBI
23.4
17.5
3.03
—
0.0218
—
0.15
1.596
0.0655
0.136
0.269
0.137
0.0521
0.447
0.203
0.015
0.041
0.0469
0.070
0.213
0.98
0.0882
0.140
0.175
0.165
0.0556
0.300
0.215
0.018
0.020
0.0416
0.058
0.173
1.35
0.386
0.2015
0.173
0.194
0.0629
0.196
0.139
0.015
—
0.0126
0.541
0.0778
1.18
0.0557
—
0.163
0.097
0.0473
0.411
0.126
0.015
—
0.0153
—
0.212
1.792
0.0926
—
0.224
0.051
0.0468
0.309
0.141
0.015
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
bThe Steel Forming and Finishing Subcategory has mass-based limits, which are being proposed based on the
General Metals Subcategory concentration-based limits. Section 14.0 provides the mass-based limits for the Steel
Forming and Finishing Subcategory and methodology for deriving the limits.
— No samples collected on this day.
CBI - Confidential Business Information.
10-32
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6C
MP&M Technology Effectiveness Concentrations for
General Metals and Steel Forming and Finishing Subcategory (Option 4)a'b
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Cadmium
4882
3.59
4.52
3.82
3.18
1.27|| 0.0072
0.005
0.0056
0.0073
0.0102
Chromium
4807
4854
4882
0.71
CBI
35.3
0.164
CBI
23.0
0.51
CBI
25.4
0.412
CBI
24.1
1.24
CBI
11.0
0.085
0.0098
0.0159
0.0154
0.0119
0.0330
0.0368
0.0170
0.0867
0.0248
0.0142
0.0954
0.017
0.017
0.468
Copper
4807
4854
4882
17.2
CBI
1.5
9.71
CBI
0.74
26.6
CBI
0.432
20.7
CBI
0.372
89.8
CBI
0.219
0.127
0.008
0.0660
0.0416
0.008
0.0205
0.0418
0.034
0.0168
0.0663
0.330
0.0124
0.0929
0.0394
0.0126
Manganese
4807
4.78
1.16
4.19
1.51
5.95|| 0.117
0.132
0.162
0.171
0.067
Nickel
4807
4854
29.0
CBI
5.06
CBI
12.3
CBI
6.94
CBI
30.9| 1.58
CBI 0.022
0.48
0.016
0.55
0.017
0.54
0.016
0.60
0.101
Silver
4807
3.13
1.79
3.39
1.92
2.48|| 0.0184
0.0006
0.0331
0.0252
0.0006
Tin
4807
0.394
1.74
2.17
0.60
1.29|| 0.0184
0.0184
0.0184
0.0184
0.0184
Zinc
4807
4854
4882
9.01
CBI
34.8
3.01
CBI
44.6
7.91
CBI
37.8
4.39
CBI
32.7
13.4
CBI
14.0
0.0576
0.008
0.028
0.0584
0.017
0.029
0.0398
0.020
0.067
0.0452
0.008
0.046
0.0002
0.008
0.011
Total Suspended Solids (TSS)
4807
4882
3080
33
152
61
2380
76
380
—
2920| 30.0
22l 4.5
17.0
4.0
23.0
4.0
13.0
4.0
27.0
4.0
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
bThe Steel Forming and Finishing Subcategory has mass-based limits, which are being proposed based on the
General Metals Subcategory concentration-based limits. Section 14.0 provides the mass-based limits for the Steel
Forming and Finishing Subcategory and methodology for deriving the limits.
— No samples collected on this day.
CBI - Confidential Business Information.
10-33
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6D
MP&M Technology Effectiveness Concentrations for
Metal Finishing Job Shops Subcategory (Option 2)a
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Total Suspended Solids (TSS)
4788
6178
6187
175.2
250.5
6266.5
97.6
534
6307.5
86.8
170.5
8532.5
103.2
—
—
708.8
—
—
13.0
16
10.5
21.0
43
12.0
12.0
10
11.0
6.5
—
—
9.0
—
—
Manganese
4278
4279
6178
6187
CBI
2.176
0.5005
9.4873
CBI
1.033
1.6975
17.312
CBI
1.236
1.7425
47.339
CBI
0.620
—
—
CBI
5.713
—
—
0.181
0.035
0.0127
0.0043
0.166
0.093
0.0216
0.0036
0.115
0.076
0.0167
0.0064
0.172
0.007
—
—
—
0.195
—
—
Tin
4788
50.95
36.51
63.67
52.71
75.34| 1.08
0.94
1.36
1.46
1.22
Total Organic Carbon (TOC) (as indicator parameter)
4788
36.4
37.0
57.6
39.6
46.4|| 48.0
42.0
68.5
50.5
43.0
Cadmium
4279
4788
6178
6187
7.6391
1.3988
2.9685
63.935
2.6358
3.436
0.9908
117.034
2.4367
1.9368
1.6622
322.825
1.4307
2.1336
—
—
7.7302
11.5484
—
—
0.0864
0.0118
0.041
0.0286
0.1756
0.0427
0.035
0.0707
0.2105
0.0225
0.029
0.0661
0.0222
0.0105
—
—
0.1896
0.0198
—
—
Chromium
4278
4279
4788
4893
6178
6187
CBI
22.559
5.568
0.269
1.084
14.358
CBI
11.269
8.062
1.82
1.82
31.745
CBI
9.668
13.198
—
4.365
93.393
CBI
7.609
11.907
—
—
—
CBI
10.352
10.887
—
—
—
0.019
0.364
0.336
0.126
0.141
0.169
0.007
0.507
0.188
0.382
0.282
0.478
0.007
0.576
0.475
—
0.626
0.396
0.033
0.180
0.236
—
—
—
—
0.834
0.05
—
—
—
Copper
4278
4279
4883
4894
CBI
3.663
0.998
0.904
CBI
1.8121
1.160
1.14
CBI
1.1632
1.06
—
CBI
0.9302
0.645
—
CBI
2.1929
1.04
—
0.035
0.0990
0.176
0.463
0.329
0.1235
0.596
0.253
0.087
0.1748
0.358
—
0.061
0.0344
0.407
—
—
0.0929
0.304
—
10-34
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6D (Continued)
Episode
Daily Influent Concentration
(mg/L, ppm)
Day 1
Day 2
Day 3
Day 4
Day 5
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day 5
Copper (continued)
6178
6187
5.74
122.18
23.875
201.475
17.0
344.128
—
—
— I! 0.221
— | 0.420
0.653
0.208
0.439
0.277
—
—
—
—
Lead
4788
6178
6187
8.314
2.840
36.585
8.074
13.595
72.053
9.726
19.643
74.443
11.084
—
—
16.168
—
—
0.165
0.035
0.084
0.127
0.070
0.044
0.152
0.055
0.075
0.244
—
—
0.196
—
—
Nickel
4278
4279
4788
4883
4894
CBI
7.141
21.267
2.05
1.71
CBI
3.847
13.464
0.786
1.12
CBI
2.619
16.572
3.36
—
CBI
3.537
15.403
1.99
—
CBI
13.153
53.733
0.605
—
0.318
0.477
0.690
0.315
0.305
0.157
0.481
0.790
0.205
0.233
0.317
0.363
0.748
0.534
—
0.596
0.058
0.679
0.465
—
—
0.527
0.342
0.182
—
Silver
4788
6178
6187
0.3122
0.2425
0.9715
0.4425
1.6425
0.8013
0.1738
2.0275
1.146
0.2374
—
—
1.4206
—
—
0.0296
0.035
0.043
0.0296
0.010
0.033
0.0068
1.080
0.020
0.005
—
—
0.0196
—
—
Zinc
4278
4279
4788
4883
4893
4894
6178
6187
CBI
93.67
1.099
0.996
0.292
0.532
1.3842
19.2285
CBI
40.33
2.074
1.13
1.67
1.40
0.813
69.7393
CBI
34.26
1.610
0.837
—
—
0.9343
175.9742
CBI
44.99
1.260
1.10
—
—
—
—
CBI
100.47
4.907
0.592
—
—
—
—
0.022
1.23
0.011
0.177
0.087
0.114
0.0463
0.0177
0.027
3.53
0.032
0.269
0.352
0.255
0.0169
0.0162
0.011
2.06
0.024
0.230
—
—
0.0161
0.0221
0.011
0.263
0.011
0.322
—
—
—
—
—
2.87
0.013
0.164
—
—
—
—
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2). Section 14.0 provides the
mass-based limits for the Steel Forming and Finishing Subcategory and methodology for deriving the limits.
— No samples collected on this day.
CBI - Confidential Business Information.
10-35
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6E
MP&M Technology Effectiveness Concentrations for
Nonchromium Anodizers Subcategory (Option 2)a
Episode
Daily Influent Concentration Daily Effluent Concentration
(mg/L, ppm) (mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day 5 Day 1
Day 2
Day 3
Day 4
Day5
Total Suspended Solids (TSS)
4856
4869
CBI
502
CBI
21
CBI
9
CBI
46
CBlll 7.0
— | 4.0
6.0
12.0
6.0
10.0
8.0
52.0
11.0
4.0
Aluminum
4856
4869
CBI
132
CBI
14.8
CBI
16.1
CBI
8.24
CBlll 2.91
— 1 1.08
2.23
0.64
3.04
1.14
3.4
4.65
5.29
0.80
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
— No samples collected on this day.
CBI - Confidential Business Information.
Table 10-6F
MP&M Technology Effectiveness Concentrations for
Printed Wiring Boards Subcategory (Option 2)a
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Manganese
4866
0.385
0.574
0.860
1.940
1.070
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
DayS
0.212
0.235
0.289
0.666
0.641
Nickel
4866
4867
2.5
0.0388
0.499
0.029
0.325
2.30
0.449
0.372
0.279
0.505
0.121
0.017
0.148
0.016
0.091
0.126
0.107
0.019
0.090
0.067
Tin
4866
4867
6.74
3.26
3.89
5.13
5.07
2.65
4.11
1.61
4.92
1.71
0.051
0.025
0.141
0.093
0.082
0.016
0.097
0.014
0.229
0.039
Total Organic Carbon (TOC) (as indicator parameter)
4866
4867
11.2
87.6
22.1
152
17.7
116
62.0
86.3
16.6
108
11.0
70.7
17.7
86.1
16.5
99.7
35.6
84.4
13.8
88.4
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
— No samples collected on this day.
CBI - Confidential Business Information.
10-36
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6G
MP&M Technology Effectiveness Concentrations for
Printed Wiring Boards Subcategory (Option 4)a
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Copper
4855
19.4
48.8
38.6
16.9
33.9|| 0.0018
0.0018
0.0018
0.0018
0.0081
Lead
4855
3.1
2.61
2.38
2.18
1.75|| 0.021
0.021
0.021
0.021
0.021
Tin
4855
6.94
5.77
4.48
4.35
2.9711 0.0403
0.0718
0.0548
0.0549
0.0517
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
— No samples collected on this day.
CBI - Confidential Business Information.
Table 10-6H
MP&M Technology Effectiveness Concentrations for
Oily Wastes Subcategory (Option 6)a
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
DayS
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
DayS
Oil and Grease (as HEM)
4851
4872
4876
4877
6883.8
696.0
2030
556.5
16642
2182.5
2230
1937.5
379.5
502.0
1760
996.7
7569.7
—
1110
544.3
334
—
3440
469
14.9
52.0
25.6
24.0
18.3
44.8
24.7
63.75
15.4
55.6
105
14.75
14.2
—
54.7
21.25
12.1
—
188
15.0
Total Sulfide (as S)
4877
14.0
5.0
4.0
14.0
17.0|| 4.5
8.0
3.0
17.0
3.0
Total Suspended Solids (TSS)
4471
4851
4872
4876
4877
96
1720
244
1670
90
82
508
242
833
275
77
373
165
1580
162
98
615
—
84
303
—
71
—
620
241
100
40
12.5
18
17
40
35
10.0
15
62
36
49
13.0
20
26
6
48
—
10
14
—
34
—
12
21
10-37
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6H (Continued)
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day 5
Total Organic Carbon (TOC) (as indicator parameter)
4851
4872
1520
1340
517
963
280
797
216
—
232
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day 5
202.0
— | 173.5
254.5
131
299.5
260
480.0
—
240.0
—
Total Organic Carbon (TOC) (as indicator parameter) - (continued)
4876
4877
928
659
1090
158
1690
289
1120
569
1650
282
493
269
313
206.5
1110
264
605
329
1270
269
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
— No samples collected on this day.
CBI - Confidential Business Information.
Table 10-61
MP&M Technology Effectiveness Concentrations for
Railroad Line Maintenance Subcategory (Option 10)a
Episode
Daily Influent Concentration Daily Effluent Concentration
(mg/L, ppm) (mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day 5 Day 1
Day 2
Day 3
Day 4
Day5
Biochemical Oxygen Demand (BOD) 5-Day (Carbonaceous)
6179
114
94
256
—
HI 4.5
5.0
6.0
—
—
Oil and Grease (as HEM)
6179
255.5
250.7
268
—
-|| 6.7
6.7
5.3
—
—
Total Suspended Solids (TSS)
6179
122
155
339
—
-II 14.5
8.5
9.0
—
—
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
— No samples collected on this day.
CBI - Confidential Business Information.
10-38
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-6J
MP&M Technology Effectiveness Concentrations for
Shipbuilding and Drydock Subcategory (Option 10)a
Episode
Daily Influent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Daily Effluent Concentration
(mg/L, ppm)
Dayl
Day 2
Day 3
Day 4
Day5
Oil and Grease (as HEM)
4891
4892
CBI
180.3
CBI
206.8
CBI
595.5
CBI
661.3
CBl| 5.6
1823| 9.3
5.5
8.5
8.3
12.0
5.3
11.7
6.3
17.2
Total Suspended Solids (TSS)
4805
4891
4892
1070
CBI
39
9
CBI
47
—
CBI
50
—
CBI
88
—
CBI
221
38
17
37.5
21
11
41
—
5
44.5
—
18
50
—
7
102
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
— No samples collected on this day.
CBI - Confidential Business Information.
10-39
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-7
Calculation of Total Organics Parameter (TOP) Limit
Total Organics Parameter Pollutants
that are also POCs
Acrolein
Benzole acid
Carbon disulfide
Dibenzofuran
Dibenzothiophene
Isophorone
n-Hexadecane
n-Tetradecane
Aniline
Chloroform (trichloromethane)
Methylene chloride (dichloromethane)
Chloroethane (ethyl chloride)
1 , 1 -Dichloroethane
1,1,1 -Trichloroethane
(methylchloroform)
1,1-Dichloroethylene (vinylidene
chloride)
Tetrachloroethylene (perchloroethylene)
Trichloroethylene
Biphenyl
p-Cymene
Ethylbenzene
Toluene
N-Nitrosodimethylamine
N-Nitrosodiphenylamine
Chlorobenzene
2,6-Dinitrotoluene
Phenol
4-Chloro-7w-cresol (/?arachloro/wetacresol
or 4-chloro-3- methylphenol)
2,4-Dinitrophenol
2,4-Dimethylphenol
2-Nitrophenol (o-nitrophenol)
4-Nitrophenol (/>-nitrophenol)
CAS Number
107-02-8
65-85-0
75-15-0
132-64-9
132-65-0
78-59-1
544-76-3
929-59-4
62-53-3
67-66-3
75-09-2
75-00-3
75-34-3
71-55-6
75-35-4
127-18-4
79-01-6
92-52-4
99-87-6
100-41-4
108-88-3
62-75-9
86-30-6
108-90-7
606-20-2
108-95-2
59-50-7
51-28-5
105-67-9
88-75-5
100-02-7
Nominal
Quantitation
Limit (mg/L)
0.05
0.05
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.05
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.05
0.02
0.01
0.01
0.01
0.01
0.05
0.01
0.02
0.05
Pollutant has data in
the LTA database
for Option 2a
X
X
X
X
X
X
X
X
X
X
X
X
10-40
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-7 (Continued)
Total Organics Parameter Pollutants
that are also POCs
Acenaphthene
Anthracene
3 ,6-Dimethylphenanthrene
Fluorene
Fluoranthene
2-Isopropylnaphthalene
1-Methylfluorene
2-Methylnaphthalene
1 -Methylphenanthrene
Naphthalene
Phenanthrene
Pyrene
Benzyl butyl phthalate
Dimethyl phthalate
Di-n-butyl phthalate
Di-n-octyl phthalate
Di(2-ethylhexyl) phthalate
Sum of nominal quantitation limits for
pollutants that are not in the LTA database
CAS Number
83-32-9
120-12-7
1576-67-6
86-73-7
206-44-0
2027-17-0
1730-37-6
91-57-6
832-69-9
91-20-3
85-01-8
129-00-0
85-68-7
131-11-3
84-74-2
117-84-0
117-81-7
Nominal
Quantitation
Limit (mg/L)
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Pollutant has data in
the LTA database
for Option T
X
X
X
X
X
X
X
X
X
X
X
0.47
1 x indicates that the pollutant has data in the LTA database for Option 2.
10-41
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8A
Episode-Level Long-Term Averages and Variability Factors for
Total and Amenable Cyanide Destruction
(All Options for Applicable Subcategories)3
Regulated
Pollutant
Total Cyanide
Amenable
Cyanide
Subcategory
General Metals
Metal Finishing
Job Shop
General Metals
General Metals
General Metals
General Metals
Metal Finishing
Job Shop
General Metals
General Metals
Shipbuilding
and Dry dock
General Metals
General Metals
Metal Finishing
Job Shop
General Metals
General Metals
Metal Finishing
Job Shop
General Metals
General Metals
General Metals
General Metals
Metal Finishing
Job Shoo
Episode
4274
4279
4384
4460A
4807
4817
4828
4834
4847
4891
4904
6048
6186
4807
4817
4828
4834
4847
4904
6048
6186
Long- Term
Average
Concentration
(mg/L, ppm)
0.01
0.01
0.77
0.02
0.027
0.443
0.092
0.02
0.012
0.088
0.257
0.207
0.196
0.02
0.54
0.064
0.020
0.010
0.119
0.016
0.0618
1-Day Variability
Factor
—
—
1.94
—
2.60
2.18
2.80
—
2.63
2.92
2.74
1.66
1.67
—
1.83
4.20
—
—
2.14
3.70
5.12
4-Day Variability
Factor
—
—
1.27
—
1.41
1.60
1.48
—
1.39
1.51
1.47
1.20
1.20
—
1.37
1.79
—
—
1.33
1.76
1.99
aData used for limits for General Metals, Metal Finishing Job Shops, Printed Wiring Board, and Steel Forming and
Finishing Subcategories.
10-42
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8B
Episode-Level Long-Term Averages and Variability Factors for
General Metals and Steel Forming and Finishing Subcategories (Option 2)a
Regulated Pollutant
Manganese
Molybdenum
Tin
Total Organic Carbon (TOC)
(as indicator parameter)
Cadmium
Chromium
Episode
4762
4807
4871
4904
4806
4904
4817
4834
4737
4761
4762
4806
4807
4817
4833
4834
4871
4904
11 97 A
4277
4415
4460
6048
11 97 A
4011
4079
4310
4330
4384
4415
Long-Term Average
Concentration6
(mg/L, ppm)
0.139
0.050
0.092
0.013
0.723
0.031
0.060
0.815
86.5
49.7
170.6
21.8
17.3
22.6
15.2
73.1
102.6
10.0
0.0705
0.174
0.0052
0.0349
0.891
0.638
0.871
0.970
2.272
0.067
0.585
0.0488
1-Day Variability
Factor
1.64
2.08
1.35
2.22
2.84
1.32
3.85
2.14
1.61
—
1.22
3.20
2.80
1.82
5.15
1.97
1.37
—
—
2.59
—
—
1.37
—
—
—
—
2.65
1.68
—
4-Day Variability
Factor
1.20
1.31
1.11
1.35
1.49
1.11
1.72
1.32
1.19
—
1.07
1.57
1.48
1.24
1.95
1.28
1.12
—
—
1.43
—
—
1.12
—
—
—
—
1.45
1.21
—
10-43
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8B (Continued)
Regulated Pollutant
Chromium (continued)
Copper
Lead
Nickel
Episode
4417
4438
4460
4470
4811
4817
4833
4847
4871
4904
4277
4737
4806
4807
4817
4833
4834
4847
4904
11 97 A
4761
4762
4834
4871
11 97 A
4277
4438
4470
4761
4762
4807
4811
4817
4833
4834
4847
4871
4904
6048
Long-Term Average
Concentration6
(mg/L, ppm)
0.0188
0.093
1.175
0.0773
0.0085
0.0925
0.0679
0.301
0.0101
0.0147
0.559
0.175
0.609
1.049
0.238
0.128
0.060
0.080
0.046
1.88
0.012
0.025
0.020
0.009
0.557
0.178
0.415
0.231
0.266
0.206
0.264
0.047
0.034
0.051
0.330
0.054
0.652
0.026
0.346
1-Day Variability
Factor
2.47
—
—
1.73
1.19
6.02
3.37
2.73
—
1.91
1.73
8.73
3.58
2.98
2.50
1.63
1.81
3.05
2.03
—
—
—
1.55
1.88
—
1.18
—
1.95
—
2.11
2.24
1.93
2.16
—
2.26
3.16
1.41
—
3.15
4-Day Variability
Factor
1.41
—
—
1.22
1.07
2.19
1.61
1.46
—
1.27
1.22
2.82
1.66
1.52
1.41
1.19
1.24
1.54
1.30
—
—
—
1.18
1.26
—
1.06
—
1.28
—
1.32
1.35
1.36
1.33
—
1.35
1.56
1.13
1.56
10-44
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8B (Continued)
Regulated Pollutant
Silver
Zinc
Oil and Grease (as HEM)
Total Suspended Solids (TSS)
Episode
11 97 A
4277
4807
4817
11 97 A
4277
4415
4417
4470
4737
4761
4762
4807
4811
4817
4871
4904
4737
4871
11 97 A
4011
4079
4277
4384
4415
4417
4438
4470
4737
4761
4762
4807
4811
4817
Long-Term Average
Concentration6
(mg/L, ppm)
0.339
0.010
0.032
0.062
0.030
0.028
0.223
0.165
1.381
0.137
0.159
0.201
0.129
0.053
0.333
0.165
0.016
13.6
6.1
26.7
26.7
6.3
14.4
45.6
1.0
7.0
6.7
17.7
24.0
22.0
14.4
8.3
4.0
11.8
1-Day Variability
Factor
—
5.89
4.02
4.08
—
3.30
—
2.41
1.69
4.45
—
1.60
3.00
1.32
2.02
1.71
—
1.51
—
—
—
—
1.62
2.52
—
3.11
—
2.87
2.84
—
1.27
2.67
—
3.54
4-Day Variability
Factor
—
2.13
1.84
1.76
—
1.59
—
1.39
1.21
1.84
—
1.19
1.53
1.10
1.29
1.22
—
1.16
—
—
—
—
1.19
1.42
—
1.60
1.50
1.49
—
1.09
1.47
—
1.67
10-45
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8B (Continued)
Regulated Pollutant
Total Suspended Solids (TSS)
(continued)
Total Sulfides (as S)c
Total Cyanide
Amenable Cyanide
Episode
4833
4834
4871
4904
4877
(d)
(d)
Long-Term Average
Concentration6
(mg/L, ppm)
8.4
14.6
5.8
5.7
7.1
(d)
(d)
1-Day Variability
Factor
2.74
7.06
2.00
2.33
4.25
(d)
(d)
4-Day Variability
Factor
1.47
2.40
1.29
1.37
1.80
(d)
(d)
aThe Steel Forming and Finishing Subcategory has mass-based limits, which are being proposed based on the
General Metals Subcategory concentration-based limits. Section 14.0 provides the mass-based limits for the Steel
Forming and Finishing Subcategory and methodology for driving the limits.
bConcentrations for pollutants not detected in a sample are reported at the detection limit. In these cases, the
detection limit was used to calculate the LTAs and variability factors.
°Data transfer from Oily Wastes Subcategory.
dSee Table 10-8A, Total and Amenable Cyanide.
— Not calculated due to insufficient data.
CBI - Confidential Business Information.
10-46
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8C
Episode-Level Long-Term Averages and Variability Factors for
General Metals and Steel Forming and Finishing Subcategories (Option 4)a
Regulated Pollutant
Cadmium
Chromium
Copper
Manganese
Nickel
Silver
Tin
Zinc
Total Suspended Solids (TSS)
Total Organic Carbon (TOC)
(as indicator parameter) d
Leadc
Oil and Grease
(as HEM)d
Molybdenum*
Episode
4882
4807
4854
4882
4807
4854
4882
4807
4807
4854
4807
4807
4855
4807
4854
4882
4807
4882
4737
4761
4762
4806
4807
4817
4833
4834
4871
4904
4855
4737
4871
4806
Long-Term Average
Concentration6
(mg/L, ppm)
0.007
0.036
0.014
0.140
0.074
0.084
0.026
0.130
0.751
0.034
0.016
0.018
—
0.040
0.012
0.036
22.0
4.1
86.5
49.7
170.6
21.8
17.3
22.6
15.2
73.1
102.6
10.0
0.021
13.6
6.136
0.723
1-Day Variability
Factor
1.81
3.95
1.69
8.61
2.78
10.79
3.91
2.21
2.75
6.80
2.94
—
1.58C
1.87
1.84
2.70
2.10
—
1.61
—
1.22
3.20
2.80
1.82
5.15
1.97
1.37
—
—
1.51
—
2.84
4-Day Variability
Factor
1.25
1.74
1.21
2.80
1.48
3.16
1.73
1.34
1.47
2.33
1.79
—
1.18°
1.49
1.36
1.52
1.31
—
1.19
—
1.07
1.57
1.48
1.24
1.95
1.28
1.12
—
—
1.16
—
1.49
10-47
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8C (Continued)
Regulated Pollutant
Total Sulfide6
Amenable Cyanide
Total Cyanide
Episode
4904
4877
(f)
(f)
Long- Term Average
Concentration6
(mg/L, ppm)
0.031
7.1
(f)
(f)
1-Day Variability
Factor
1.32
4.25
(f)
(f)
4-Day Variability
Factor
1.11
1.80
(f)
(f)
aThe Steel Forming and Finishing Subcategory has mass-based limits, which are being proposed based on the
General Metals Subcategory concentration-based limits. Section 14.0 provides the mass-based limits for the Steel
Forming and Finishing Subcategory and methodology for driving the limits.
bConcentrations for pollutants not detected in a sample are reported at the detection limit. In these cases, the
detection limit was used to calculate the LTAs and variability factors.
"Data transfer from Printed Wiring Board Subcategory Option 4.
dData transfer from General Metals Subcategory Option 2.
eData transfer from Oily Wastes Subcategory.
fSee Table 10-8A, Total and Amenable Cyanide.
— Not calculated due to insufficient data.
CBI - Confidential Business Information.
10-48
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8D
Episode-Level Long-Term Averages and Variability Factors for
Metal Finishing Job Shops Subcategory (Option 2)
Regulated Pollutant
Manganese
Tin
Total Organic Carbon (TOC)
(as indicator parameter)
Cadmium
Chromium
Copper
Lead
Silver
Episode
4278
4279
6178
6187
4788
4788
4279
4788
6178
6187
4278
4279
4788
4893
6178
6187
4278
4279
4883
4894
6178
6187
4788
6178
6187
4788
6178
6187
Long-Term
Average
Concentration3
(mg/L, ppm)
0.158
0.081
0.017
0.005
1.213
50.4
0.137
0.021
0.035
0.055
0.016
0.492
0.257
0.254
0.350
0.348
0.128
0.105
0.368
0.358
0.438
0.302
0.177
0.053
0.068
0.0181
0.3750
0.0323
1-Day Variability
Factor
1.58
8.27
—
—
1.49
1.55
5.75
3.16
—
—
4.45
3.25
5.12
—
—
—
5.79
3.41
2.56
—
—
—
1.73
—
—
4.42
—
—
4-Day Variability
Factor
1.18
2.71
—
—
1.15
1.17
2.13
1.56
—
—
1.85
1.58
1.99
—
—
—
2.14
1.62
1.42
—
—
—
1.22
—
—
1.86
—
—
10-49
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8D (Continued)
Regulated Pollutant
Zinc
Molybdenum15
Nickel
Total Organic Carbon (TOC)
(as indicator parameter)
Total Sulfidec
Total Cyanide
Amenable Cyanide
Episode
4278
4279
4788
4883
4893
4894
6178
6187
4806
4904
4278
4279
4788
4883
4894
4788
4877
(d)
(d)
Long-Term
Average
Concentration3
(mg/L, ppm)
0.0178
1.989
0.018
0.232
0.220
0.185
0.026
0.019
0.723
0.031
0.070
0.381
0.650
0.340
0.269
50.4
7.1
(d)
(d)
1-Day Variability
Factor
1.82
6.54
2.76
1.85
—
—
—
—
2.84
1.32
4.36
5.68
2.09
2.71
—
1.55
4.25
(d)
(d)
4-Day Variability
Factor
1.35
2.31
1.47
1.25
—
—
—
—
1.49
1.11
1.83
2.12
1.31
1.46
—
1.17
1.80
(d)
(d)
a Concentrations for pollutants not detected in a sample are reported at the detection limit. In these cases, the
detection limit was used to calculate the LTAs and variability factors.
b Data transfer from General Metals Subcategory Option 2.
0 Data transfer from Oily Wastes Subcategory.
d See first table under Table 10-8A, Total and Amenable Cyanide.
— Not calculated due to insufficient data.
CBI - Confidential Business Information.
10-50
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8E
Episode-Level Long-Term Averages and Variability Factors for
Metal Finishing Job Shops (Option 4)
Regulated Pollutant
Total Suspended Solidsb
Manganese15
Tin
Total Organic Carbon (TOC) (as
indicator parameter)
Cadmium
Chromiumb
Copperb
Leadd
Silverb
Zincb
Oil and Grease (as HEM)C
Molybdenum0
Nickelb
Total Organic Carbon (TOC) (as
indicator parameter)
Episode
4807
4882
4807
4807 (a)
4855 (c)
4788
4882
4807
4854
4882
4807
4854
4882
4855
4807
4807
4854
4882
4737
4871
4806
4904
4807
4854
4788
Long-Term
Average
Concentration3
(mg/L, ppm)
22.0
4.10
0.130
0.018
—
50.4
0.007
0.036
0.014
0.140
0.074
0.084
0.026
0.021
0.016
0.040
0.012
0.036
13.6
6.14
0.031
0.315
0.751
0.034
50.4
1-Day Variability
Factor
2.10
—
2.21
—
1.58
1.55
1.8
3.95
1.69
8.61
2.78
10.79
3.91
—
2.94
1.87
1.84
2.70
1.51
—
2.84
1.32
2.75
6.80
1.55
4-Day Variability
Factor
1.31
—
1.34
—
1.18
1.17
1.25
1.74
1.21
2.80
1.48
3.16
1.73
—
1.79
1.49
1.36
1.52
1.16
—
1.49
1.11
1.47
2.33
1.17
10-51
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8E (Continued)
Regulated Pollutant
Total Sulfide (e)
Total Cyanide
Amenable Cyanide
Episode
4877
(f)
(f)
Long-Term
Average
Concentration3
(mg/L, ppm)
7.1
(f)
(f)
1-Day Variability
Factor
4.25
(f)
(f)
4-Day Variability
Factor
1.80
(f)
(f)
a Concentrations for pollutants not detected in a sample are reported at the detection limit. In these cases, the
detection limit was used to calculate the LTAs and variability factors.
b Data transfer from General Metals Subcategory Option 4.
0 Data transfer from General Metals Subcategory Option 2.
dData transfer from Printed Wiring Board Subcategory Option 4.
e Data transfer from Oily Wastes Subcategory.
f See Table 10-8A, Total and Amenable Cyanide.
— Not calculated due to insufficient data.
CBI - Confidential Business Information.
10-52
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8F
Episode-Level Long-Term Averages and Variability Factors for
Nonchromium Anodizing Subcategory (Option 2)
Regulated Pollutant
Total Suspended Solids (TSS)
Aluminum
Manganese15
Nickelb
Zincb
Episode
4856
4869
4856
4869
4762
4807
4871
4904
11 97 A
4277
4438
4470
4761
4762
4807
4811
4817
4833
4834
4847
4871
4904
6048
11 97 A
4277
4415
4417
4470
4737
4761
4762
Long-Term Average
Concentration3
(mg/L, ppm)
7.6
16.4
3.374
1.663
0.139
0.050
0.092
0.013
0.557
0.178
0.415
0.231
0.266
0.206
0.264
0.047
0.034
0.051
0.330
0.054
0.652
0.026
0.346
0.030
0.028
0.223
0.165
1.380
0.137
0.159
0.201
1-Day Variability
Factor
1.74
6.92
1.98
4.48
1.64
2.08
1.35
2.22
—
1.18
—
1.95
—
2.11
2.24
1.93
2.16
—
2.26
3.16
1.41
—
3.15
—
3.30
—
2.41
1.69
4.45
—
1.60
4-Day Variability
Factor
1.22
2.38
1.29
1.85
1.20
1.31
1.11
1.35
—
1.06
—
1.28
—
1.32
1.35
1.36
1.33
—
1.35
1.56
1.13
1.56
—
1.59
—
1.39
1.21
1.84
—
1.19
10-53
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8F (Continued)
Regulated Pollutant
Zinc (continued)
Oil and Grease (as HEM) b
Episode
4807
4811
4817
4871
4904
4737
4871
Long-Term Average
Concentration3
(mg/L, ppm)
0.129
0.053
0.333
0.165
0.016
13.6
6.13
1-Day Variability
Factor
3.00
1.32
2.02
1.71
—
1.51
—
4-Day Variability
Factor
1.53
1.10
1.29
1.22
—
1.16
—
""Concentrations for pollutants not detected in a sample are reported at the detection limit. In these cases, the
detection limit was used to calculate the LTAs and variability factors.
bData transfer from General Metals Subcategory Option2.
— Not calculated due to insufficient data.
CBI - Confidential Business Information.
10-54
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8G
Episode-Level Long-Term Averages and Variability Factors for
Printed Wiring Boards Subcategory (Option 2)
Regulated Pollutant
Total Cyanide
Amenable Cyanide
Chromium0
Copper0
Episode
(b)
(b)
11 97 A
4011
4079
4310
4330
4384
4415
4417
4438
4460
4470
4811
4817
4833
4847
4871
4904
4277
4737
4806
4807
4817
4833
4834
4847
4904
Long- Term Average
Concentration3
(mg/L, ppm)
(b)
(b)
0.638
0.871
0.970
2.272
0.067
0.585
0.0488
0.0188
0.093
1.175
0.0773
0.0085
0.0925
0.0679
0.301
0.0101
0.0147
0.559
0.175
0.609
1.049
0.238
0.128
0.060
0.080
0.046
1-Day Variability
Factor
(b)
(b)
—
—
—
—
2.65
1.68
—
2.47
—
—
1.73
1.19
6.02
3.37
2.73
—
1.91
1.73
8.73
3.58
2.98
2.50
1.63
1.81
3.05
2.03
4-Day Variability
Factor
(b)
(b)
—
—
—
—
1.45
1.21
—
1.41
—
—
1.22
1.07
2.19
1.61
1.46
—
1.27
1.22
2.82
1.66
1.52
1.41
1.19
1.24
1.54
1.30
10-55
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8G (Continued)
Regulated Pollutant
Leacf
Manganese
Nickel
Tin
Zincb
Total Organic Carbon (TOC)
(as indicator parameter)
Total Sulfided
Episode
11 97 A
4761
4762
4834
4871
4866
4866
4867
4866
4867
11 97 A
4277
4415
4417
4470
4737
4761
4762
4807
4811
4817
4871
4904
4866
4867
4877
Long-Term Average
Concentration3
(mg/L, ppm)
1.88
0.012
0.025
0.020
0.009
0.409
0.111
0.049
0.120
0.037
0.030
0.028
0.223
0.165
1.381
0.137
0.159
0.201
0.129
0.053
0.333
0.165
0.016
19.0
85.9
7.1
1-Day Variability
Factor
—
—
—
1.55
1.88
3.10
1.58
5.81
3.17
4.69
—
3.30
—
2.41
1.69
4.45
—
1.60
3.00
1.32
2.02
1.71
—
2.53
1.32
4.25
4-Day Variability
Factor
—
—
—
1.18
1.26
1.55
1.18
2.15
1.56
1.90
—
1.59
—
1.39
1.21
1.84
—
1.19
1.53
1.10
1.29
1.22
—
1.42
1.11
1.80
""Concentrations for pollutants not detected in a sample are reported at the detection limit. In these cases, the
detection limit was used to
calculate the LTAs and variability factors.
b See Table 10-8A, Total and Amenable Cyanide.
0 Data transfer from General Metals Subcategory Option 2.
d Data transfer from Oily Wastes Subcategory.
— Not calculated due to insufficient data.
CBI - Confidential Business Information.
10-56
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8H
Episode-Level Long-Term Averages and Variability Factors for
Printed Wiring Boards Subcategory (Option 4)
Regulated Pollutant
Chromiumb
Copper
Lead
Manganese15
Nickelb
Oil and Grease (as HEM)b
Total Sulfided
Tin
Total Organic Carbon (TOC)
(as indicator parameter)6
Total Suspended Solids (TSS) b
Zincb
Amenable Cyanide
Total Cyanide
Episode
4807
4854
4882
4855
4855
4807
4807
4854
4737
4871
4877
4855
4866
4867
4807
4882
4807
4854
4882
(f)
(f)
Long-Term Average
Concentration3
(mg/L, ppm)
0.036
0.014
0.140
0.003
0.021
0.130
0.751
0.034
13.6
6.13
7.1
0.0547
19.0
85.9
22.0
4.1
0.040
0.012
0.036
(f)
(f)
1-Day Variability
Factor
3.95
1.69
8.61
—
—
2.21
2.75
6.80
1.51
—
4.25
1.58
2.53
1.32
2.10
—
1.87
1.84
2.70
(f)
(f)
4-Day Variability
Factor
1.74
1.21
2.80
—
—
1.34
1.47
2.33
1.16
—
1.80
1.18
1.42
1.11
1.31
—
1.49
1.36
1.52
(f)
(f)
a Concentrations for pollutants not detected in a sample are reported at the detection limit. In these cases, the
detection limit was used to calculate the LTAs and variability factors.
b Data transfer from General Metals Subcategory Option 4.
c Data transfer from General Metals Subcategory Option 2.
d Data transfer from Oily Wastes Subcategory.
e Data transfer from Printed Wiring Board Subcategory Option 2.
f See Table 10-8A, Total and Amenable Cyanide.
— Not calculated due to insufficient data.
CBI - Confidential Business Information.
10-57
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-81
Episode-Level Long-Term Averages and Variability Factors for
Oily Waste Subcategory (Option 6)
Regulated Pollutant
Oil and Grease (as HEM)
Total Sulfide
Total Organic Carbon (TOC)
(as indicator parameter)
Total Suspended Solids (TSS)
Episode
4851
4877
4877
4851
4872
4876
4877
4471
4851
4872
4876
4877
Long-Term Average
Concentration3
(mg/L, ppm)
15.0
18.8
7.1
295
188
758
267
45.5
41.2
11.8
15.0
19.5
1-Day Variability
Factor
1.4
1.72
4.25
2.04
—
3.26
1.45
7.73
1.47
—
1.86
1.80
4-Day Variability
Factor
1.13
1.22
1.80
1.30
—
1.58
1.14
2.59
1.15
—
1.26
1.24
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
10-58
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-8J
Railroad Line Maintenance Subcategory (Option 10)
Regulated Pollutant
BOD 5-Day (Carbonaceous)
Total Suspended Solids (TSS)
Oil and Grease (as HEM)
Episode
6179
4891b
4892 b
4891b
4892b
6179
4892b
4891b
6179
Long-Term
Average
Concentration3
(mg/L, ppm)
5.17
—
—
—
—
10.7
—
—
6.22
1-Day Variability
Factor
—
6.90
6.03
3.13
2.34
—
1.71
1.82
—
4-Day Variability
Factor
—
2.39
2.19
1.55
1.37
—
1.19
1.25
—
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
bData transfer from Shipbuilding Dry Dock Subcategory.
—No samples collected on this day.
CBI - Confidential Business Information.
Table 10-8K
Shipbuilding Dry Dock Subcategory (Option 10)
Regulated Pollutant
Oil and Grease (as HEM)
Total Suspended Solids (TSS)
Episode
4891
4892
4805
4891
4892
Long- Term Average
Concentration3
(mg/L, ppm)
6.2
11.8
29.5
11.6
55.0
1-Day Variability
Factor
1.71
1.82
—
3.13
2.34
4-Day Variability
Factor
1.19
1.25
—
1.55
1.37
Tollutants not detected in an effluent sample are reported at the detection limit. In these cases, concentrations at
influent to treatment were determined to be at treatable concentrations (see Section 10.2).
—No samples collected on this day.
CBI - Confidential Business Information.
10-59
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9A
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
General Metals Option 2
Regulated
Parameter
Total Suspended Solids
(TSS)
Oil and Grease
(as HEM)
Total Organic Carbon
(TOC) (as indicator
parameter)
Total Organics
Parameter (TOP)
Cadmium
Chromium
Copper
Total Cyanide
Amenable Cyanide
Lead
Manganese
Molybdenum
Nickel
Silver
Total Sulfide
Tin
Zinc
Number of
Sites (LTA)
19
2
10
42
5
17
9
13
8
5
4
2
15
4
1
2
13
Number of
Sites (VF)
12
1
8
12
2
9
9
9
5
2
4
2
10
3
1
2
9
Median
LTA
(mg/L,
ppm)
12
9.9
37
2.3
0.08
0.10
0.17
0.09
0.04
0.02
0.07
0.38
0.24
0.05
7.1
0.44
0.16
1-Day
Variability
Factor
2.9
1.6
2.4
3.9
2.0
2.7
3.2
2.4
3.4
1.8
1.9
2.1
2.2
4.7
4.3
3.0
2.4
4-Day
Variability
Factor
1.5
1.2
1.4
1.8
1.3
1.5
1.6
1.4
1.65
1.3
1.3
1.3
1.4
2.0
1.80
1.6
1.4
Maximum
Daily
(mg/L,
ppm)
34
15
87
9.0
0.14
0.25
0.55
0.21
0.14
0.04
0.13
0.79
0.50
0.22
31
1.4
0.38
Maximum
Monthly
Avg.
(mg/L,
ppm)
18
12
50
4.3
0.09
0.14
0.28
0.13
0.07
0.03
0.09
0.49
0.31
0.09
13
0.67
0.22
10-60
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9B
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
General Metals Subcategory (Option 4)
Regulated
Parameter
Total Suspended Solids
(TSS)
Oil and Grease (as
HEM)
Total Organic Carbon
(TOC) (as indicator
parameter)
Total Organics
Parameter
Cadmium
Chromium
Copper
Total Cyanide
Amenable Cyanide
Lead
Manganese
Molybdenum
Nickel
Silver
Total Sulfide
Tin
Zinc
Number of
Sites (LTA)
2
2
10
42
1
3
3
13
8
1
1
2
2
1
1
1
o
J
Number of
Sites (VF)
1
1
8
12
1
3
o
6
9
5
—
1
2
2
1
1
1
o
J
Median
LTA
(mg/L,
ppm)
13
9.9
37
2.3
0.01
0.04
0.08
0.09
0.04
0.03
0.13
0.38
0.40
0.02
7.1
0.02
0.04
1-Day
Variability
Factor
2.1
1.6
2.4
3.9
1.8
4.8
5.9
2.4
3.4
1.6
2.3
2.1
4.7
3.0
4.3
1.6
2.2
4-Day
Variability
Factor
1.4
1.2
1.4
1.8
1.3
2.0
2.2
1.4
1.7
1.2
1.4
1.3
1.9
1.8
1.8
1.2
1.5
Maximum
Daily
(mg/L,
ppm)
28
15
87
9.0
0.02
0.17
0.44
0.21
0.14
0.04
0.29
0.79
1.88
0.05
31
0.03
0.08
Maximum
Monthly
Avg.
(mg/L,
ppm)
18
12
50
4.3
0.01
0.07
0.16
0.13
0.07
0.03
0.18
0.49
0.75
0.03
13
0.03
0.06
10-61
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9C
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
Metal Finishing Job Shops Subcategory (Option 2)
Regulated
Parameter
Total Suspended Solids
(TSS)
Oil and Grease
(as HEM)
Total Organic Carbon
(as indicator parameter)
Total Organics
Parameter
Cadmium
Chromium
Copper
Total Cyanide
Amenable Cyanide
Lead
Manganese
Molybdenum
Nickel
Silver
Total Sulfide
Tin
Zinc
Number of
Sites (LTA)
NA
NA
1
42
4
6
6
13
8
3
4
2
5
3
1
1
8
Number of
Sites (VF)
NA
NA
1
12
2
3
3
9
5
1
2
2
4
1
1
1
4
Median
LTA (mg/L,
ppm)
NA
NA
51
2.3
0.05
0.31
0.34
0.09
0.04
0.07
0.05
0.38
0.39
0.04
7.1
1.3
0.11
1-Day
Variability
Factor
NA
NA
1.6
3.9
4.5
4.3
4.0
2.4
3.4
1.8
5.0
2.1
3.7
4.5
4.3
1.5
3.3
4-Day
Variability
Factor
NA
NA
1.2
1.8
1.9
1.8
1.8
1.4
1.7
1.3
2.0
1.3
1.7
1.9
1.8
1.2
1.6
Maximum
Daily
(mg/L,
ppm)
60a
52a
78
9.0
0.21
1.3
1.3
0.21
0.14
0.12
0.25
0.79
1.5
0.15
31
1.8
0.35
Maximum
Monthly
Avg.
(mg/L,
ppm)
31a
26a
59
4.3
0.09
0.55
0.58
0.13
0.07
0.09
0.10
0.49
0.64
0.06
13
1.4
0.17
a For existing sources, limits are transferred from 40 CFR 433 (Metal Finishing).
NA - Not applicable.
10-62
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9D
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
Metal Finishing Job Shops Subcategory (Option 4)
Regulated
Parameter
Total Suspended Solids
(TSS)
Oil and Grease (as
HEM)
Total Organic Carbon
(TOC) (as indicator
parameter)
Total Organics
Parameter
Cadmium
Chromium
Copper
Total Cyanide
Amenable Cyanide
Lead
Manganese
Molybdenum
Nickel
Silver
Total Sulfide
Tin
Zinc
Number of
Sites (LTA)
2
2
1
42
1
3
o
5
13
8
1
1
2
2
1
1
1
o
J
Number of
Sites (VF)
1
1
1
12
1
3
o
5
9
5
—
1
2
2
1
1
1
o
J
Median
LTA
(mg/L,
ppm)
13
9.9
51
2.3
0.01
0.04
0.08
0.09
0.04
0.03
0.13
0.38
0.40
0.02
7.1
0.02
0.04
1-Day
Variability
Factor
2.1
1.6
1.6
3.9
1.8
4.8
5.9
2.4
3.4
1.6
2.3
2.1
4.7
3.0
4.3
1.6
2.2
4-Day
Variability
Factor
1.4
1.2
1.2
1.8
1.3
2.0
2.2
1.4
1.7
1.2
1.4
1.3
1.9
1.8
1.8
1.2
1.5
Maximum
Daily
(mg/L,
ppm)
28
15
78
9.0
0.02
0.17
0.44
0.21
0.14
0.04
0.29
0.79
1.88
0.05
31
0.03
0.08
Maximum
Monthly
Avg.
(mg/L,
ppm)
18
12
59
4.3
0.01
0.07
0.16
0.13
0.07
0.03
0.18
0.49
0.75
0.03
13
0.03
0.06
10-63
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9E
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
Non-Chromium Anodizing Subcategory (Option 2)
Regulated
Parameter
Total Suspended Solids
(TSS)
Oil and Grease (as
HEM)
Aluminum
Manganese
Nickel
Zinc
Number of
Sites (LTA)
2
2
2
4
15
13
Number of
Sites (VF)
2
1
2
4
10
9
Median
LTA
(mg/L,
ppm)
12
9.9
2.6
0.07
0.24
0.16
1-Day
Variability
Factor
4.4
1.6
3.3
1.9
2.2
2.4
4-Day
Variability
Factor
1.8
12
1.6
1.3
1.4
1.4
Maximum
Daily
(mg/L,
ppm)
52 a
15a
8.2
0.13
0.50
0.38
Maximum
Monthly
Avg.
(mg/L,
ppm)
22 a
12 a
4.0
0.09
0.31
0.22
a As shown in Section 14.0 EPA transferred limits for TSS and oil and grease for existing sources from 40 CFR 433 (Metal Finishing).
The limits for TSS and oil and grease shown in this table are being proposed for new sources.
10-64
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9F
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
Printed Wiring Boards (Option 2)
Regulated
Parameter
Total Suspended Solids
(TSS)
Oil and Grease (as
HEM)
Total Organic Carbon
(TOC) (as indicator
parameter)
Total Organics
Parameter
Chromium
Copper
Total Cyanide
Amenable Cyanide
Lead
Manganese
Nickel
Total Sulfide
Tin
Zinc
Number of
Sites (LTA)
NA
NA
2
42
17
9
13
8
5
1
2
1
2
13
Number of
Sites (VF)
NA
NA
2
12
9
9
9
5
2
1
2
1
2
9
Median
LTA
(mg/L,
ppm)
NA
NA
53
2.3
0.10
0.18
0.09
0.04
0.02
0.41
0.08
7.1
0.08
0.16
1-Day
Variability
Factor
NA
NA
2.0
3.9
2.7
3.2
2.4
3.4
1.8
3.1
3.7
4.3
4.0
2.4
4-Day
Variability
Factor
NA
NA
1.3
1.8
1.5
1.6
1.4
1.7
1.3
1.6
1.7
1.8
1.8
1.4
Maximum
Daily
(mg/L,
ppm)
60 a
52 a
101
9.0
0.25
0.55
0.21
0.14
0.04
1.3
0.30
31
0.31
0.38
Maximum
Monthly
Avg.
(mg/L,
ppm)
31a
26a
67
4.3
0.14
0.28
0.13
0.07
0.03
0.64
0.14
13
0.14
0.22
1 For existing sources, limits are transfered from 40 CFR 433 (Metal Finishing).
10-65
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9G
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
Printed Wiring Boards (Option 4)
Regulated
Parameter
Total Suspended Solids (TSS)
Oil and Grease (as HEM)
Total Organic Carbon (TOC)
(as indicator parameter)
Total Organics Parameter
(TOP)
Chromium
Copper
Total Cyanide
Amenable Cyanide
Lead
Manganese
Nickel
Total Sulfide
Tin
Zinc
Number
of Sites
(LTA)
2
2
2
42
3
1
13
8
1
1
2
1
1
3
Number
of Sites
(VF)
1
1
2
12
o
J
9
5
1
2
1
1
3
Median
LTA
(mg/L,
ppm)
13
9.9
53
2.3
0.4
0.01
0.09
0.04
0.03
0.13
0.40
7.1
0.06
0.04
1-Day
Variabilit
y Factor
2.1
1.6
2.0
3.9
4.8
1.6
2.4
3.4
1.6
2.3
4.7
4.3
1.6
2.2
4-Day
Variability
Factor
1.4
1.2
1.3
1.8
2.0
1.2
1.4
1.7
1.2
1.4
1.9
1.8
1.2
1.5
Maximum
Daily1
28
15
101
9.0
0.17
0.01
0.21
0.14
0.04
0.29
1.88
31
0.09
0.08
Maximum
Monthly
Avg.1
18
12
67
4.3
0.07
0.01
0.13
0.07
0.03
0.18
0.75
13
0.07
0.06
10-66
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9H
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
Oily Wastes Subcategory (Option 6)
Regulated
Parameter
Total Suspended Solids
(TSS)
Oil and Grease
(as HEM)
Total Organic Carbon
(TOC) (as indicator
parameter)
Total Organics
Parameter
Total Sulfide
Number of
Sites (LTA)
5
2
4
42
1
Number of
Sites (VF)
4
2
3
12
1
Median
LTA
(mg/L,
ppm)
20
17
282
2.3
7.1
1-Day
Variability
Factor
3.3
1.6
2.3
3.9
4.3
4-Day
Variability
Factor
1.6
1.2
1.4
1.8
1.8
Maximum
Daily
(mg/L,
ppm)
63
27
633
9.0
31
Maximum
Monthly
Avg.
(mg/L,
ppm)
31
20
378
4.3
13
Table 10-91
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
Railroad Line Maintenance Subcategory (Option 10)
Regulated
Parameter
5-Day Biochemical
Oxygen Demand
(BOD5)
Total Suspended Solids
(TSS)
Oil and Grease
(as HEM)
Number of
Sites (LTA)
1
1
1
Number of
Sites (VF)
2
2
2
Median
LTA
(mg/L,
ppm)
5.2
11
6.3
1-Day
Variability
Factor
6.5
2.8
1.8
4-Day
Variability
Factor
2.3
1.5
1.3
Maximum
Daily
(mg/L,
ppm)
34
30
11
Maximum
Monthly
Avg.
(mg/L,
ppm)
12
16
7.6
10-67
-------
10.0 - Long-Term Averages and Variability Factors
Table 10-9J
Pollutant-Level Long-term Averages, Variability Factors and Limitations for
Shipbuilding Dry Docks Subcategory (Option 10)
Regulated
Parameter
Total Suspended Solids
(TSS)
Oil and Grease
(as HEM)
Number of
Sites (LTA)
3
2
Number of
Sites (VF)
2
2
Median
LTA (mg/,
ppml)
30
9.0
1-Day
Variability
Factor
2.8
1.8
4-Day
Variability
Factor
1.5
1.3
Maximum
Daily
(mg/L,
ppm)
81
16
Maximum
Monthly
Avg.
(mg/L,
ppm)
44
11
Source: MP&M LTA Database.
10-68
-------
11.0 - Costs of Technology Bases for Regulations
11.0 COSTS OF TECHNOLOGY BASES FOR REGULATIONS
This section describes the methodology used to estimate the costs for
implementing each of the technology options under consideration for the MP&M Point Source
Category. Section 8.0 describes the technologies considered and Section 9.0 describes the
combination of these technologies into options for in-process source reduction and recycling and
end-of-pipe wastewater treatment. The cost estimates, together with the pollutant reduction
estimates described in Section 12.0, provide a basis for evaluating the options discussed in
Section 9.0. The cost estimates also provide a basis for determining the economic impact of the
regulation on the industry as discussed in the report titled Economic. Environmental & Benefit
Analysis of the Proposed Metal Products & Machinery Rule (EEBA) (1). The EEBA is included
in the public record for this rulemaking.
EPA used the following approach to estimate compliance costs for the MP&M
industry.
Select probability samples of MP&M industry sites to receive industry
surveys (see Section 3.0). EPA estimated costs of compliance for each
survey site (i.e., model site) based on factors such as unit operations,
wastewater characteristics, treatment currently in place, etc. (see Section
11.2).
Analyze field sampling data for unit operations to determine the pollutant
concentrations of untreated wastewater in the industry (see Section 12.0).
• Identify candidate in-process source reduction and recycling and end-of-
pipe wastewater treatment technologies, and group them into technology
options. The technology options serve as the basis of compliance cost and
pollutant loading calculations (see Section 9.0).
Analyze field sampling data for wastewater treatment systems to
determine pollutant removal performance of the selected technologies (see
Section 10.0).
Develop cost equations for capital and operating and maintenance (O&M)
costs for each of the technologies (see Section 11.4).
• Evaluate the current (baseline) treatment technology in place at each
model site (i.e., survey site) and estimate baseline pollutant loadings and
operating and maintenance costs using a computerized design and cost
model (the MP&M Design and Cost Model).
11-1
-------
11.0 - Costs of Technology Bases for Regulations
Use the MP&M Design and Cost Model to estimate compliance costs
(presented in Section 11.2) and pollutant loadings (presented in Section
12.0) for each model site for each option.
Use sample weights based on survey sample frame to estimate, for
national population, industry compliance costs and pollutant loadings.
• Estimate total annualized costs, cost effectiveness, and the economic
impact to the industry (presented in the EEB A) using output from the
MP&M Design and Cost Model.
EPA estimated industry-wide costs for 10 technology options by computing
compliance costs for technology trains at 890 model sites. The Agency used these model sites to
estimate costs for 63,000 water-discharging MP&M sites using statistically calculated industry
weighting factors (i.e., sample weights). Many of these 63,000 MP&M sites are indirect
dischargers with flows under the proposed low flow exclusions and are not included in the final
cost estimates of the proposed rule. Section 11.1 summarizes the results of the costing effort.
Section 11.2 presents the methodology used to select and develop model sites. Section 11.3
presents the methodology for estimating costs, including descriptions of the components that
define capital and annual costs, sources of cost data, standardization of cost data, an overview of
the MP&M Design and Cost Model, and general assumptions used for costing. Section 11.4
describes the design and costing methodology for each in-process and end-of-pipe technology
used in the options. Tables are presented in the text and figures are located at the end of this
section.
11.1 Summary of Costs
EPA identified several in-process and end-of-pipe technologies applicable to
MP&M wastewater (Section 8.0), and combined these into technology options (Section 9.0).
Overall, EPA considered 10 technology options, although several options are only applicable to
certain MP&M subcategories. Based on the technologies included in each option and the
specific wastewater generated at the MP&M model sites (based on questionnaire responses),
EPA used the MP&M Design and Cost Model to estimate compliance costs for each model site
for each option.
Table 11-1 presents annualized costs for both direct and indirect dischargers by
subcategory for all proposed options for existing sources (Options 2, 6, 10). Costs for options
that EPA did not propose are not presented in this section but are discussed in Section 14. EPA
notes that costs for options 1, 3, 5, 7, and 9 (those options without pollution prevention (P2) cost
more and remove fewer pollutants than the comparable technology with pollution prevention (see
Section 14).
Cost estimates presented in Table 11-1 will not equate with those presented in the
EEBA because those costs include other system annual costs (e.g., taxes and amortization). In
11-2
-------
11.0 - Costs of Technology Bases for Regulations
addition, EEBA cost estimates are presented in 1999 dollars (where costs in this section are in
1996 dollars), and the EEBA cost estimates do not include costs for facilities that are projected to
close in the baseline based on a site's responses to EPA's economic portion of industry
questionnaires, (i.e., based on a site's responses to EPA's economic portion of industry
questionnaires, EPA estimates these facilities will close, regardless of the MP&M effluent
guidelines, prior to the implementation of the MP&M guidelines).
11-3
-------
Table 11-1
11.0 - Costs of Technology Bases for Regulations
MP&M Total Estimated Annualized Costs
at the Proposed Options for Existing Sources
Subcategory
General Metals
Metal Finishing Job Shop
Non-Chromium Anodizing
Printed Wiring Board
Steel Forming and Finishing
Oily Waste
Railroad Line Maintenance
Shipbuilding Dry Dock
All Categories: Annualized Costs
Proposed
Option
Number
2
2
2
2
2
6
10
10
2/6/10
Direct Dischargers
Number of
Sites
3,794
15
NA
11
43
911
34
6
4.814
Total Annualized Cost
(millions of 1996 dollars)
230
1.3
NA
2.5
29.3
11.2
1.18
2.15
280
Indirect Dischargers
Number of
Sites
3,055
1,514
Not
Proposed
621
110
226
Not
Proposed
Not
Proposed
5.530
Flow
Cutoff
1MGY
None
None
None
None
2MGY
None
None
Total Annualized Cost
(millions of 1996
dollars)
1,570
178
Not Proposed
147
24
10
Not Proposed
Not Proposed
1.930
Source: MP&M Design and Cost Model.
NA - Not applicable, EPA's data collection efforts have not identified any direct discharging non-chromium anodizing facilities.
Note: Cost estimates presented in this table will not equate with those presented in the EEBA. The cost estimates in the EEBA are presented in 1999 dollars and
do not include costs for facilities that are projected to close in the baseline.
-------
11.0 - Costs of Technology Bases for Regulations
11.2 Model Site Development
The Agency used a model site approach to estimate costs for the 63,000 water-
discharging sites in the MP&M Point Source Category based on cost estimates for a statistically
sampled subset of sites. To account for the variability in processes and treatment systems in
place within the MP&M Point Source Category, EPA developed a model site from each survey
(see Section 3.0) that met the criteria described below.
11.2.1 Site Selection
EPA selected model sites from sites receiving industry surveys. Section 3.1
discuss data collection and survey activities. The Agency selected a site as a model site if it met
the following criteria:
The site discharged wastewater (treated or untreated) to either a surface
water or publicly owned treatment works (POTW); and
• The site supplied sufficient technical data required to estimate compliance
costs and pollutant loadings reductions associated with the technology
options.
Based on these criteria, EPA selected 890 survey respondents for model site
development. The Agency used statistically-determined survey weights to estimate the national
MP&M industry population of 63,000 sites. Development of the survey weights and the
statistical methodology used to characterize the industry are documented in the public record for
this rulemaking.
11.2.2 Wastewater Stream Parameters
Based on the information provided by the sites in their survey responses, follow-
up letters, and phone calls, EPA classified each process wastewater stream at each site by the
type of unit operation (e.g., machining, electroplating, acid treatment) generating the wastewater.
For each operation, EPA used survey data to obtain the following parameters:
• Wastewater discharge flow rate. For each process wastewater stream,
sites reported the total wastewater discharge flow rate from the unit
operation. For sites that did not report wastewater discharge data, EPA
statistically imputed wastewater flow rates using other data provided in the
site's survey or by using data for similar unit operations reported in other
surveys. The approach for this modeling is documented in the public
record for this rulemaking.
Production rate. Sites reported production rates in either surface area
processed, mass of metal removed, or air flow rate. The production
11-5
-------
11.0 - Costs of Technology Bases for Regulations
parameter used depended on the unit operation. EPA used surface area for
surface finishing or cleaning operations, mass of metal removed for metal
removal operations such as machining and grinding, and air flow rate for
air pollution control operations. For sites that did not report production
data, EPA statistically imputed production rates using other data provided
in the site's survey or by using data for similar unit operations reported in
other surveys. The approach for this modeling is documented in the public
record for this rulemaking.
Operating schedule. EPA used survey responses to estimate the
operating rate (hours per day (hpd) and days per year (dpy)) of each unit
operation when supplied by sites. For blank responses, EPA used the
following:
- The maximum hpd and dpy reported by the site for other unit
operations;
The survey response for wastewater treatment system operating
schedule, if all hpd and dpy responses at the unit operation level
were blank; or
8 hpd and 250 dpy, if all unit operation operating rate survey
responses were blank and no wastewater treatment system
operating schedule was provided.
• Discharge destination. EPA used survey responses to determine whether
each unit operation discharged process wastewater, and if so, whether the
wastewater was discharged to a surface water or POTW. EPA also
determined from the survey responses whether the wastewater was treated
on site prior to discharge. The MP&M Design and Cost Model did not
assign costs to wastewater that sites reported to be contract hauled off site,
deep-well injected, discharged to septic systems, not discharged, or reused
on site. For sites that did not report a discharge destination for some or all
operations, EPA modeled the destination based on other technical
information provided in the survey (e.g., types of discharge permits,
discharge destination of other unit operations, process flow diagrams).
11.2.3 Pollutant Concentrations
The Agency estimated the concentration of each pollutant in each model site's
process wastewater stream using field sampling data for raw wastewater discharged from MP&M
unit operations. Section 3.0 discusses the field sampling program. EPA used these data with
survey flow and production data to calculate the pollutant loadings. Section 12.0 discusses these
calculations in more detail as well as the calculations for estimating site specific pollutant
11-6
-------
11.0 - Costs of Technology Bases for Regulations
removals. In addition, Section 10 provides information about the data used to estimate pollutant
concentrations in the effluent stream following treatment for the various technology options.
11.2.4 Technology in Place
The term "technology in place" refers to those technologies that the Agency
considered to be installed and operating at a model site at the time the facility completed the
detailed industry survey. EPA accounted for technology in place in the costing and pollutant
removal efforts to ensure that EPA accurately assessed the treatment costs associated with a
facility upgrading its treatment system (including P2) to meet the MP&M standards and the
current level of pollutant being discharged by facilities with treatment in place.
Although both the 1989 and 1996 MP&M Detailed Surveys requested detailed
information on end-of-pipe treatment-in-place, only the 1996 MP&M Detailed Survey requested
information about a facility's in-process pollution prevention technologies. For the 1996 MP&M
Detailed Surveys, EPA assigned pollution prevention technology in place based on information
contained in the responses to this survey. For other model sites, the Agency assumed in-process
pollution prevention technologies were in place for a particular unit operation if the model site's
process wastewater stream had a production-normalized flow rate (PNF, volume of wastewater
per unit of production) below the median PNF calculated from the 1996 MP&M Detailed Survey
for processes incorporating that pollution prevention technology. For example, if a 1989 survey
site reported a machining wastewater stream with a PNF below the median PNF for
centrifugation and pasteurization of machining coolant, then the Agency assumed that the model
site had a machining coolant regeneration system in place. The median PNFs for each
technology are listed in Section 15 and documented in the public record for this rulemaking.
EPA used a similar method to give credit to sites using efficient rinse schemes.
EPA used the following parameters to compute flow reductions and costs for incorporating
pollution prevention in rinse lines by converting the rinse to a two-stage countercurrent rinse.
Additional information on the in-process pollution prevention and rinse flow reduction
methodology can be found in the public record for this rulemaking.
• Tank volume. Although tank volume is a design parameter for
countercurrent cascade rinsing, the Agency did not request this
information in the surveys. EPA used a linear relationship between tank
size and annual discharge flow rate to estimate the volume of the existing
tank and for the estimated volumes of additional rinse tank(s) that may
need to be installed in order to incorporate countercurrent cascade rinsing.
• Rinse code. EPA uses the rinse code parameter to compute a flow
reduction for conversion of the model site's current rinse scheme to a two-
stage countercurrent rinse. The 1996 MP&M Detailed Surveys contained
specific information about each rinse. EPA used this information to
determine the median PNF for each of the five general rinse categories.
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As documented in the public record for this rulemaking, EPA assigned
rinses from all surveys one of the five general rinse codes based on
specific rinse code information contained in the survey or the PNF for the
rinse stream. The Agency used these codes to estimate rinse flow
reduction costs for model sites that do not currently use countercurrent
rinsing.
Equipment code. EPA determined the type of rinse equipment in place
and assigned an equipment code based on the detailed rinse information in
the 1996 surveys. For surveys that did not contain detailed information,
EPA used the model site's PNF to assign an equipment code.
EPA reviewed survey data for each model site to assess the types of preliminary
and end-of-pipe technologies in place at each site (e.g., chemical reduction of chromium, sludge
pressure filtration). EPA identified end-of-pipe technologies on site that, based on technical
considerations, it considered equivalent to technologies included in the technology options. For
example, the Agency considered vacuum filtration to be equivalent to pressure filtration for
sludge dewatering. EPA also identified technologies that it did not consider equivalent, and for
which it assigned no credit for technology in place. For example, EPA did not consider oil/water
separation equivalent to ultrafiltration in the technology options; however, it did consider
ultrafiltration to be treatment in place for treatment options specifying oil/water separation or
dissolved air flotation. EPA assumed that sites specifying only chemical precipitation also had a
clarifier. In addition, the Agency assumed sites with treatment systems in place have the
associated chemical feed systems in place. Site-specific assumptions regarding treatment
technologies in place at model sites are included in the administrative record for this rulemaking
(Technology in Place Documentation for MP&M Phase I/II Survey Respondents, DCN
16323/15799).
EPA used survey data for the following parameters to assess the capacity of the
end-of-pipe technologies in place at the model sites:
• Operating schedule. EPA used survey responses to estimate the
operating schedule (hours per day (hpd) and days per year (dpy)) for each
treatment unit when supplied by sites. For blank responses, EPA
determined the schedule using the following:
The maximum hpd and dpy reported for the unit operations, if all
hpd and dpy responses for the treatment unit were blank;
- The maximum hpd and dpy reported by the site for other unit
operations associated with other treatment units; or
8 hpd and 250 dpy, if all hpd and dpy survey responses were blank
for unit operations and treatment units.
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Wastewater streams treated. EPA determined the unit operation
wastewater streams treated by each end-of-pipe technology in place using
the following:
Survey process flow diagrams or responses to survey questions
regarding the destination of individual process wastewater streams,
and
The logic used by the model for assigning streams to technologies
if information provided in the survey was insufficient, (e.g., EPA
assumed that sites treated cyanide-bearing streams using cyanide
destruction if the site currently had it in place). This logic is
described in Section 11.3.
EPA used the baseline operating schedule and wastewater streams treated by the
technology to define the maximum operating capacity for each technology. The Agency
determined design capacity flow from the larger of the survey response flow (when available) or
the model design capacity flow as derived from the baseline flow. EPA assumed that each model
site with end-of-pipe treatment technologies in place operated their system at 78 percent of full
capacity (at baseline). The Agency estimated the operating capacity based on an average of
survey data (documentation is included in the public record for this rulemaking). Because a site
may need to increase its wastewater treatment capacity as a result of the process changes
associated with some of EPA's technology options, Section 11.3.4 presents assumptions
regarding how the model accounted for baseline end-of-pipe technologies with insufficient
capacity.
11.3 Methodology for Estimating Costs
This section discusses the methodology for estimating costs, including the
components of cost (Section 11.3.1), the sources and standardization of cost data (Section
11.3.2), the MP&M Design and Cost Model (Section 11.3.3), and the general assumptions made
during the costing effort (Section 11.3.4).
11.3.1 Components of Cost
The components of the capital and annual costs and the terminology used in
developing these costs are presented below.
Capital Costs
The capital costs consist of two major components: direct capital costs and
indirect capital costs. The direct capital costs include:
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Purchased equipment cost, including ancillary equipment (e.g., piping,
valves, controllers);
• Delivery cost (based on the equipment weight and a shipping distance of
500 miles); and
Installation cost (including labor and site work).
EPA derived the direct components of the total capital cost separately for each
treatment unit or pollution prevention technology. When possible, EPA obtained costs for
various sizes of preassembled, skid-mounted treatment units from equipment vendors. If costs
for preassembled, skid-mounted treatment units were not available, EPA obtained catalog prices
for individual system components (e.g., pumps, tanks, feed systems) and summed these prices to
estimate the cost for the treatment unit.
Indirect capital costs consist of secondary containment, engineering, contingency,
and contractor fees. When combined with the direct capital costs, these form the total capital
investment. EPA estimates the indirect costs as percentages of the total direct capital cost, as
shown in Table 11-2.
Table 11-2
Components of Total Capital Investment
Item
Number
1
2
3
4
5
6
7
Item
Equipment capital costs including required accessories,
installation, delivery, electrical and instrumentation, yard
piping, enclosure, pumping, and retrofit allowance
Engineering/administrative and legal
Secondary containment/land costs
Total plant cost
Contingency
Contractor's fee
Total capital investment
Cost
Direct capital cost
10% of item 1
10% of item 1
Sum of items 1 through 3
15% of item 4
5% of item 4
Sum of items 4 through 6
Source: MP&M Design and Cost Model.
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Annual Costs
As with capital costs, the annual costs have both a direct and an indirect
component. The equations used to calculate individual equipment direct annual costs include the
following.
• Raw material costs. Chemicals and other materials used in the treatment
processes (e.g., calcium hydroxide, sulfuric acid, sodium hypochlorite);
• Operating labor and material costs. The labor and materials directly
associated with operation of the process equipment;
• Maintenance labor and material costs. The labor and materials required
for repair and routine maintenance of the equipment; and
• Energy costs. Calculated based on total energy requirements (in kW-hrs).
Indirect annual costs include monitoring, taxes, insurance, and amortization.
Monitoring is the periodic analysis of wastewater effluent samples to ensure that discharge
limitations are being met. Section 11.3.2 discusses assumptions regarding monitoring frequency.
The EEBA discusses taxes and amortization.
Total Annualized Costs
EPA calculated total annualized costs (TAG) from the capital and annual costs
generated by the MP&M Design and Cost Model. The Agency assumed a 7 percent discount rate
over an estimated 15-year equipment life.
11.3.2 Sources and Standardization of Cost Data
EPA obtained capital and annual cost data for the technologies that constitute
EPA's technology options (see Section 9) from equipment vendors, literature, and from existing
MP&M sites. The Agency used specific data from the 1989 and 1996 MP&M Detailed Surveys
whenever possible; however, the required types of data were often either not collected or not
supplied by the sites. The major sources of equipment cost data were equipment vendors, while
the literature provided most of the annual cost information.
Capital and annual cost data were standardized to 1996 dollars (the most current
year in which EPA collected survey data) based on the following:
• Capital Equipment. EPA adjusted capital costs obtained in 1998 dollars
to 1996 dollars using —Means Building Construction Historical Cost
Indexes (see Table 11-3). The values of this index for 1996 and 1998
were 110.2 and 114.4, respectively. EPA decreased capital equipment
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costs by 3.7 percent (110.2/114.4 x 100) to account for inflationary
changes between 1996 and 1998.
Chemicals. EPA used the Chemical Marketing Reporter from December,
1997 to obtain chemical prices.
Water and Sewer Costs. EPA based water and sewer use prices on data
collected through an EPA Internet search of various public utilities located
throughout the United States for years ranging from 1996 to 1999. EPA
adjusted rates to a 1996 basis using the —Means Building Construction
Historical Cost Indexes. The average water and sewer use charges were
$2.03 per 1,000 gallons and $2.25 per 1,000 gallons, respectively.
Energy. EPA determined electricity prices from the U.S. Department of
Energy's Energy Information Administration. The average electrical cost
to industrial users from 1994 to 1996 was $0.047 per kW-hr.
Labor. EPA used labor rate of $29.67 per hour to convert the labor
requirements of each technology into annual costs. The Agency obtained
the base labor rate from the Monthly Labor Review, which is published by
the U.S. Bureau of Labor Statistics of the U.S. Department of Labor.
Excluding the maximum and minimum values, EPA used the largest
remaining monthly value for 1997 for production labor in the fabricated
metals industry, $12.90 per hour, as a conservative estimate. The Agency
added 15 percent of the base labor rate for supervision and 100 percent for
overhead to obtain the labor rate of $29.67 per hour.
Monitoring. EPA did not include the annual cost of wastewater analyses
because it assumed that no incremental monitoring costs would be
incurred at the technology options above a site's current baseline
monitoring.
Contract Hauling. EPA based contract-hauling costs on averaged data
from the 1996 MP&M Detailed and Screener Surveys as discussed in
Section 11.4.4. The Agency estimated costs for contract hauling of RCRA
hazardous metal hydroxide sludge from Pollution Prevention and Control
Technology for Plating Operations (3). The contract hauling costs for
various waste types are provided in Table 11-4.
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Table 11-3
RSMeans Building Construction Historical Cost Indexes
Year
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
Index
92.1
94.3
96.8
99.4
101.7
104.4
107.6
110.2
112.8
114.4
Reference: Historical Cost Indexes, RSMeans Building Construction Cost Data, 56th
Annual Edition, 1998, page 594. (2)
Table 11-4
Contract-Hauling Costs for Various Waste Types
11.3.3
Waste Type
RCRA hazardous non-hazardous paint sludge
RCRA hazardous metal hydroxide sludge (3)
RCRA non-hazardous oil
Solvent (paint and paint stripping waste)
Oily wastewater
General metal-bearing wastewater
Cyanide-bearing wastewater
Hexavalent chromium-bearing wastewater
Chelated metal-bearing wastewater
Cost ($/gallon)
3.70
1.95
0.86
2.85
1.33
2.00
5.64
3.51
1.40
Source: 1996 MP&M Detailed and Screener Surveys.
MP&M Design and Cost Model
The Agency developed cost modules for the in-process source reduction and
recycling and end-of-pipe wastewater treatment technologies and practices included in the
technology options. Table 11-5 presents these technologies and practices. Specific details
regarding the design and costing of each technology and practice are described in Section 11.4.
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Figure 11-1 shows the relationship between in-process and end-of-pipe technologies and
practices.
Table 11-5
Wastewater Treatment Technologies and Source Reduction
and Recycling Practices for Which EPA Developed Cost Modules
In-Process Technologies and Practices
End-Of-Pipe Technologies and Practices
Countercurrent cascade rinsing
Centrifugation and pasteurization of machining
coolants
Centrifugation of painting water curtains
Chemical reduction of hexavalent chromium
Cyanide destruction
Chemical reduction of chelated metals
Chemical emulsion breaking
Gravity oil/water separation
Dissolved air flotation
Gravity oil emulsion breaking (baseline only, see
Section 11.3.4)
Ultrafiltration for oil removal
Contract hauling of solvent degreasing wastewaters
Chemical precipitation
Gravity clarification for solids removal
Microfiltration for solids removal
Sludge thickening
Sludge pressure filtration
Multimedia filter (baseline only, see Section 11.3.4)
Source: MP&M surveys, MP&M site visits, technical literature.
EPA developed a computerized design and cost model to estimate compliance
costs and pollutant loadings for the MP&M technology options, taking into account each site's
treatment in place. The model was programmed with modules, which allowed the user to specify
various combinations of technologies and pollution prevention practices to be costed as required
by the technology options and as required by each model site's wastewater stream characteristics.
A baseline run estimated current annual costs (operating and maintenance) for each site and
assessed the current capacity of treatment equipment in place using the site's specified treatment
equipment and the estimated wastewater flow requiring a particular type of treatment. For
estimating costs and pollutant loadings for each of the technology options, the model costed each
site by assigning a particular type of treatment unit to each wastestream generated by the site
(see Table 11-6). EPA took into account current treatment in place and existing annual costs (for
chemical addition, etc.) from baseline when estimating costs associated with the proposed rule.
EPA designated specifically which unit operations would feed each treatment unit (or pollution
prevention technology) based on the properties of that unit operation's discharge stream (e.g.,
cyanide bearing wastewater feeds cyanide destruction, flowing rinses feed countercurrent cascade
rinsing).
In the context of the MP&M cost program, "model" refers to the overall computer
program and "module" refers to a computer subroutine that generates costs and pollutant
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loadings for a specific in-process or end-of-pipe technology or practice (e.g., chemical
precipitation and sedimentation, contract hauling). EPA adapted some modules from cost
modules used for previous EPA rulemaking efforts for the metals industry, while it developed
others specifically for this rulemaking effort.
Table 11-6
List of Unit Operations Feeding Each Treatment Unit
or In-Process Technology
Treatment Unit / P2 Equipment
Countercurrent cascade rinsing
Unit Operations Feeding Unit3
Acid treatment with chromium rinse
Acid treatment without chromium rinse
Alkaline cleaning for oil removal rinse
Alkaline treatment with cyanide rinse
Alkaline treatment without cyanide rinse
Anodizing with chromium rinse
Anodizing without chromium rinse
Aqueous degreasing rinse
Barrel finishing rinse
Chemical conversion coating without chromium rinse
Chemical milling rinse
Chromate conversion coating rinse
Corrosion preventive coating rinse
Electrochemical machining rinse
Electroless plating rinse
Electrolytic cleaning rinse
Electroplating with chromium rinse
Electroplating with cyanide rinse
Electroplating without chromium or cyanide rinse
Electropolishing rinse
Heat treating rinse
Salt bath descaling rinse
Solvent degreasing rinse
Stripping (paint) rinse
Stripping (metallic coating) rinse
Testing rinse
Washing finished products rinse
Carbon black deposition rinse
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Table 11-6 (Continued)
Treatment Unit / P2 Equipment
Countercurrent cascade rinsing (cont.)
Centrifiguration and pasteurization of
machining coolant
Centrifugation of painting water
curtains
Chemical emulsion breaking and
Oil/water separation
OR
Dissolved air flotation
OR
Ultrafiltration system for oil removal
Unit Operations Feeding Unit3
Galvanizing/hot dip coating rinse
Mechanical plating rinse
Laundering rinse
Cyanide rinsing
Ultrasonic machining rinse
Phosphor deposition rinse
Multiple unit operation rinse
Grinding
Machining
Painting - spray or brush
Painting - immersion
Alkaline cleaning for oil removal and rinse
Aqueous degreasing
Assembly /disassembly
Electrical discharge machining rinse
Electrolytic cleaning
Electroplating without chromium or cyanide
Floor cleaning and rinse
Grinding rinse
Heat treating
Impact deformation and rinse
Machining and rinse
Painting - spray or brush
Painting - immersion
Pressure deformation
Stripping (paint)
Stripping (metallic coating) rinse
Testing
Thermal cutting rinse
Washing finished products and rinse
Bilge water
Mechanical plating
Photo image developing
Photo imaging
Steam cleaning
Vacuum impregnation
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Table 11-6 (Continued)
Treatment Unit / P2 Equipment
Chemical reduction of hexavalent
chromium
Chemical reduction of chelated metals
Cyanide destruction
Solvent hauling
Unit Operations Feeding Unit3
Laundering
Calibration
Centrifugation and pasteurization of machining coolant
Acid treatment with chromium and rinse
Anodizing with chromium and rinse
Chromate conversion coating and rinse
Electroplating with chromium and rinse
Stripping (paint)
Wet air pollution control - chromium
Chromium drag-out reduction and rinse
Electroless plating and rinse
Alkaline treatment with cyanide and rinse
Electroplating with cyanide and rinse
Cyanide rinsing and rinse
Cyanide drag-out destruction and rinse
Wet air pollution control - cyanide
Solvent degreasing
a Note - A unit operation can feed more than one treatment unit or in-process pollution prevention technology. EPA
assumed that the model sites commingled all MP&M wastewater generated for treatment by chemical precipitation,
except for wastewater from the Oily Wastes, the Shipbuilding Dry Dock and Railroad Line Maintenance
subcategories, and except for solvent-bearing wastewater which EPA costed for off-site disposal.
Figure 11-2 shows the logic used by the MP&M Design and Cost Model to apply
the in-process technologies and pollution prevention practices to each site. For streams at model
sites that EPA determined to not have technology in place (see Section 11.2.4), EPA applied flow
reductions for each in-process technology as summarized below:
• EPA estimated a 20 to 80 percent flow reduction achieved by converting
the current rinse scheme in place to countercurrent cascade rinsing.
EPA assumed centrifugation and pasteurization of machining coolants
reduced coolant use by 80 percent.
• EPA assumed centrifugation of painting water curtains achieved zero
discharge of wastewater through 100 percent reuse of the treated
wastewater in the painting booth (sludge removed from the centrifuge is
contract hauled).
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For countercurrent cascade rinsing, EPA estimated costs for each individual rinse
stream at a site. EPA assumed that a site combined all wastewater from machining operations
prior to centrifugation and pasteurization of machining coolants and combined wastewater from
painting streams prior to paint curtain centrifugation.
Figure 11-3 presents the logic used by the MP&M Design and Cost Model to
apply the end-of-pipe treatment technologies and practices for the following subcategories:
General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed Wiring Board,
and Steel Forming and Finishing. In developing costs, EPA assumed sites would segregate
wastewater streams from the unit operations and the in-process pollution prevention technologies
(when applicable) according to pollutant characteristics (chromium, cyanide, chelated metals, oil,
and solvent). Segregation of wastestreams provides for the most efficient and effective treatment
of wastes. Solvent-bearing wastewater streams were contract hauled for off-site disposal, while
the other segregated wastewater streams received preliminary treatment. EPA's Design & Cost
Model combined the effluent from the preliminary treatment technologies with other wastewater
streams not requiring preliminary treatment then treated the combined wastewater by chemical
precipitation and sedimentation. The Cost Model sends the sludge from chemical precipitation
to thickening and pressure filtration prior to contract hauling for off-site disposal. Finally, the
Cost Model assumes a wastewater discharge from the chemical precipitation and sedimentation
system to either a surface water or POTW according to the model site's current discharge
destination (see Section 11.3.4 for general discharge status assumptions for sites with multiple
discharge destinations).
Figure 11-4 presents the logic used by the MP&M Design and Cost Model to
apply the end-of-pipe treatment technologies and pollution prevention practices for the Oily
Wastes, Railroad Line Maintenance, and Shipbuilding Dry Dock subcategories. Each of these
subcategories generates wastewater that primarily contains oily constituents; therefore, EPA did
not include chemical precipitation and sedimentation following oil treatment in the Cost Model.
The model provided the following information, as applicable, for each technology
designed for a model site:
Total direct capital costs;
• Total direct annual costs;
Electricity used and associated cost;
• Sludge generation and associated disposal costs;
Waste oil generation and associated disposal costs;
• Water use reduction and associated cost credit;
Chemical usage reduction and associated cost credit;
• Effluent flow rate; and
Effluent pollutant concentrations.
Section 11.4 provides specific information calculated by each technology module.
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11.3.4 General Assumptions Made During the Costing Effort
This section presents general assumptions that EPA applied throughout the
MP&M Design and Cost Model. Technology-specific assumptions are presented under the
appropriate technology descriptions in Section 11.4.
Calculation of Baseline Parameters
As discussed in Section 11.2.4, EPA determined the technologies in place,
including the operating schedules and the wastewater streams treated as specified in the MP&M
survey by the model site. Using this survey information, EPA modeled each site's current costs
and pollutant loads, referred to as baseline values. EPA uses baseline values as the basis for
determining the incremental costs and loads associated with each technology option. Before
running the Cost Model for any of the technology options, EPA conducted a baseline run of the
model to determine the following:
Baseline (survey year) operating and maintenance costs incurred by sites in
1996 dollars;
• Baseline non-water quality impacts such as electricity usage, sludge
generation, and waste oil generation;
Baseline pollutant loadings; and
Capacity flow rate of each wastewater treatment technology in place.
Because the purpose of the baseline run was to simulate the current treatment
practices at each site, this run included technologies (e.g., batch emulsion breaking and gravity
flotation, multimedia filtration) that EPA did not include in the technology options. The baseline
run also reflected treatment combinations currently used by model sites that the Agency did not
use in the technology options (e.g., gravity oil/water separation followed by ultrafiltration, batch
emulsion breaking and gravity flotation followed by dissolved air flotation). As a conservative
estimate for estimating baseline pollutant loadings (loadings prior to compliance with these
proposed regulations), EPA assumed that all sites with treatment currently in place (including
those sites not currently covered by the Metal Finishing regulations) were currently meeting the
long-term average (LTA) concentrations (i.e., design concentrations) for the pollutants limited
under the Metal Finishing effluent guidelines (40 CFR Part 433) and were meeting the LTA
concentrations achieved by EPA's sampled BAT facilities for other pollutants of concern (i.e.,
those pollutants not regulated under 40 CFR Part 433). For sites that did not report treatment in
place, EPA estimated baseline pollutant loadings on EPA's unit operation-by-unit operation
sampling data for raw wastewater.
EPA subtracted the baseline values for operating and maintenance costs, non-
water quality impacts, and pollutant loadings from the corresponding values calculated from each
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technology option to determine the incremental impact in relation to the baseline for each
technology option.
End-of-Pipe Technology in Place
EPA designed the Cost Model to account for in-process and end-of-pipe operating
equipment already in place at the model sites. For end-of-pipe treatment technologies, EPA
reviewed information in the surveys to assess which of the treatment technologies included in
each option were in place at the sites. Some sites had no technologies in place, some had
incomplete treatment in place, and others had complete treatment in place. EPA also assessed
the design capacity flow for each treatment unit in place to determine whether each site had
sufficient capacity to treat all of its MP&M process wastewater. The Agency derived design
capacity flow from the larger of the site's reported survey value or the site's Cost Model design
capacity flow (as derived from the baseline flow), assuming baseline flow was 78 percent of
capacity (EPA based this assumption on the average value reported in surveys). For some
treatment options, EPA's Cost Model selected treatment for a wastewater stream (see Table 11-
6) that differed from the treatment utilized by the site at baseline. This situation sometimes
required a treatment unit at a model site to treat additional wastewater streams at the EPA option.
In these situations, the treatment capacity of the technology in place at baseline may have been
insufficient. EPA made the following assumptions regarding capital costs and end-of-pipe
technology capacities:
• If the technology was not in place at the model site, then EPA assigned
capital costs to the site for a treatment unit of sufficient capacity;
If the technology was in place at the model site with sufficient capacity to
treat all of the wastewater, then EPA assigned no capital costs; and
• If the technology was in place at the model site but with insufficient
capacity to treat all of the wastewater, then EPA assumed the site would
operate the existing system at full capacity and EPA assigned capital costs
to the site for an additional treatment unit to operate in parallel with the
existing unit to treat the additional flow.
Additionally, EPA assumed that some sedimentation and oil treatment systems
qualified as treatment in place for multiple options. For example, a microfiltration system for
solids removal would be considered treatment in place for either microfiltration or clarification
depending on the technology option, while a clarifier would only be considered treatment in
place for clarification. Table 11-7 lists the technologies that EPA considered treatment in place
for various options for both sedimentation and oil treatment.
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Table 11-7
Sedimentation and Oil Treatment Technologies Considered
Treatment in Place for Various Technology Options
Technology Specified by Option
Microfiltration for solids removal
Clarification
Ultrafiltration for oil removal
Dissolved air flotation
Chemical emulsion breaking and gravity oil/water
separation.
Technologies Considered
Treatment in Place
Microfiltration
Clarification or microfiltration
Ultrafiltration
Dissolved air flotation or Ultrafiltration
Chemical emulsion breaking and gravity oil/water
separation, batch chemical emulsion breaking and
gravity flotation, dissolved air flotation, or
Ultrafiltration
Contract Hauling in Lieu of Treatment
EPA assessed the cost of contract hauling wastewater for off-site treatment
compared to on-site treatment. Because many MP&M sites have flow rates lower than the
minimum design capacity of the treatment unit, EPA determined that it is often less expensive for
a model site to contract haul wastewater for off-site disposal rather than to treat it on site. To
assess contract hauling in lieu of treatment, EPA compared the costs of contract hauling the
wastewater with the costs of the treatment unit that would be used to treat it on site. If contract
hauling was less expensive than treating on site, EPA's Cost Model assigned the site costs
associated with contract hauling the wastewater. EPA based this determination on individual
technologies and their influent flow rates rather than on the total site wastewater treatment
system. For example, for a particular site, it may be less expensive to contract haul cyanide-
bearing wastewater in lieu of treatment while still treating all other wastewater streams on site.
The calculation for determining whether treatment on site was less expensive assumed an
equipment life expectancy of 15 years and an annual interest rate of 7 percent.
EPA compared the following technologies to contract hauling in lieu of treatment:
• Centrifugation and pasteurization of machining coolants;
Centrifugation of painting water curtains (general metal-bearing waste and
paint sludge);
• Chemical reduction of hexavalent chromium;
• Cyanide destruction;
Chemical reduction of chelated metals;
• Chemical emulsion breaking and gravity oil/water separation;
Dissolved air flotation;
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Ultrafiltration for oil removal;
• Chemical precipitation and sedimentation; and
Sludge pressure filtration.
In the case of wastewater requiring chemical precipitation and sedimentation
treatment, EPA compared the costs of contract hauling the untreated end-of-pipe wastewater to
the cost of the entire treatment system, which includes chemical precipitation, sedimentation
(gravity clarification or microfiltration), sludge thickening, and pressure filtration.
Equipment Size Ranges
EPA developed equipment cost equations for each component of the treatment
technologies. The validity ranges represent the minimum and maximum sizes (e.g., flow rates,
volume capacities) for which EPA developed the equations. For wastewater streams requiring
equipment with a capacity below the minimum range of validity, the cost model designed the
equipment at the minimum size. For wastewater streams requiring equipment with a capacity
above the maximum range of validity, the cost model designed multiple units of equal capacity to
operate in parallel such that the equipment sizes were within the range of validity.
Batch Schedules
EPA designed either batch or continuous systems, depending on each model site's
operating schedule and discharge flow rate. For batch systems, EPA determined the batch
volume and operating schedule to minimize costs. If the volume of wastewater to be treated in a
single day was less than the capacity of the minimum batch system size based on vendor
information, then the Agency altered the site's wastewater treatment operating schedule such that
the minimum system would be operated at capacity. For example, if the minimum cyanide
destruction system was 480 gallons per batch, and a site generated 80 gallons of cyanide-bearing
wastewater per day, then the Cost Model designed the cyanide destruction system to treat a 480-
gallon batch once every six days.
Dilute Influent Concentrations
In rare cases, high wastewater flow rates at some sites resulted in pollutant
concentrations below the long-term average technology effectiveness concentrations (discussed
in Section 10.0) even after EPA applied its in-process pollution prevention practices to reduce
the site's flow. In these cases, the Cost Model did not design or provide costs for a technology at
the EPA option for that wastewater stream. When this situation occurred during the baseline run
of the model, the Cost Model assigned costs for technologies in place.
Discharge Status
EPA classified a stream's discharge status as direct, indirect, contract haul, reuse,
or zero discharge. Some model sites discharge their wastewater streams to multiple discharge
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destinations at baseline. Although the Cost Model allows segregated streams to be contract
hauled for off-site disposal, it assumes the model site combines the wastewater sent to treatment
prior to chemical precipitation and sedimentation. Therefore, EPA assigned a single discharge
status to each model site based on the following assumptions:
• EPA considered a site with any combination of individual MP&M streams
with a direct discharging stream a direct discharging site;
• EPA considered a site with any combination of individual MP&M
streams, except direct, with an indirect discharging stream an indirect
discharging site; and
• EPA considered a site with any combination of individual MP&M
streams, except direct and indirect, a zero discharger/contract-hauled site.
11.4 Design and Costs of Individual Technologies
This section discusses in detail the design and costing of the individual
technologies that comprise the technology options. Additional documentation is included in the
public record for this rulemaking. Table 11-8 presents capital and annual cost equations for the
specific equipment mentioned in each technology description below.
11.4.1 Countercurrent Cascade Rinsing
The Agency applied costs for countercurrent cascade rinses for flowing rinses at
the model sites (see Table 11-6). EPA gave treatment in place credit to facilities with
countercurrent cascade rinsing in place at baseline. The countercurrent cascade rinse module
applies a flow reduction to rinses and a cost associated with the conversion to a two-stage
countercurrent rinse. The Agency assigned flow reductions ranging from approximately 20
percent to 80 percent based on the site's current PNF and type of rinsing equipment. EPA used
information from the 1996 MP&M Detailed Survey responses to determine the percentages of
flow reductions, as documented in the public record for this rulemaking. (See Section 15.2.4 for
more information on countercurrent cascade rinsing flow reduction as related to the site's
existing rinse scheme).
EPA applied costs based on the site's current rinse scheme. The module included
capital and annual costs for the following equipment when necessary.
• A second rinse tank with a volume equal to the volume of the existing
tank;
Transfer pumps and piping; and
• An air-agitation system.
EPA did not include additional operating and maintenance costs for
countercurrent cascade rinses because these would be the same as for the original rinse. Direct
annual costs for this module included energy costs and a credit for water-use reduction. EPA
11-23
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11.0 - Costs of Technology Bases for Regulations
based the cost credit for water-use savings on the annual flow reduction for each countercurrent
cascade rinse system and an average source water charge (as determined in Section 11.3.2).
11-24
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Table 11-8
11.0 - Costs of Technology Bases for Regulations
MP&M Equipment Cost Equations8
Equipment
Equation
Range of Validity
Countercurrent cascade A= [(0.0004*TANKVOL + 0.2243)] *DPY*HPD*0.047]
rinsing - [(Y-CCFLOW)*60*HPD*DPY*0.00203]
C= 6.047*TANKVOL + 3784.3 Tank, piping, and
Pump
C= 0.5077*TANKVOL + 1077.8 ^Piping and pump
C= 8*29.67 | Labor only
Machine coolant A = [18*0.047*DPY*HPD] + [(HPD/8)*DPY*29.67] + [(DPY/5)*29.67] + ¥• 14
regeneration system [0.002*Y*60*HPD*DPY*1.95]+ [0.05*Y*60*HPD*DPY*0.86] -
(including holding tanks) [0.05*0.80*Y*60*HPD*DPY*9.03] - [0.95*0.8*Y*60*HPD*DPY*0.00203]
C= 41,422 ¥• 1
^ C= 110,205 !<¥• 2
C= 142,831 2
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11.0 - Costs of Technology Bases for Regulations
Table 11-8 (Continued)
Equipment
Feed system, aluminum
sulfate (alum)
Feed system, calcium
chloride, continuous
Feed system, calcium
hydroxide (lime), continuous
Feed system, ferric sulfate,
continuous
Feed system, polymer
Feed system, sodium
hydroxide, continuous
(caustic)
A =
A =
C =
A =
C =
A =
C =
A =
C =
A =
C =
A =
C =
A =
C =
A =
C =
Equation Range of Validity
[1.36*HPD*DPY*0.047] + [0.0006615*Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] + Y < 350
[(DPY/5)*29.67]
[1.49*HPD*DPY*0.047] + [0.0006615*Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] + Y • 350
[(DPY/5)*29.67] ^
9.7882*Y + 9,718.7
[[(0.0061*Y)+1.1696]*HPD*DPY*0.047] + [0.00125*Y*60*HPD*DPY] + Y • 350
[(HPD/8)*DPY*29.67] + [(DPY/5)*29.67]
28.805*Y+ 10,683
[[(0.0006*Y)+1.2961]*HPD*DPY*0.047] + [0.0001 17*Y*60*HPD*DPY] + Y • 350
[(HPD/8)*DPY*29.67] + [(DPY/5)*29.67]
24.586*Y+ 12,830
[[(0.0009*Y)+1.3313]*HPD*DPY*0.047] + [0.0000434*Y*60*HPD*DPY] + Y • 350
[(HPD/8)*DPY*29.67] + [(DPY/5)*29.67]
11.56*Y + 9,762.9
[0.2833*HPD*DPY*0.047] + [0.001*Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] + Y < 10
[(DPY/5)*29.67]
3,686
[[(0.0034*Y)+1.4171]*HPD*DPY*0.047] + [0.001*Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] + 10 • Y • 4,000
[(DPY/5)*29.67]
20.685*Y + 9,822
[0. 1864*HPD*DPY*0.047] + [0.0042*Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] + Y < 10
[(DPY/5)*29.67]
5,120
[((0.0071*Y)+1.1584)*HPD*DPY*0.047] + [0.0042*Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] 10 • Y • 4,000
+ [(DPY/5)*29.67]
77.564*Y + 21,506
to
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11.0 - Costs of Technology Bases for Regulations
Table 11-8 (Continued)
Equipment
Equation
Range of Validity
Feed system, sulfuric acid A = [0.0373 *HPD*DPY*0.047] + [0.000222*Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] + Y < 10
[(DPY/5)*29.67]
C= 4,938
A = [[(0.0023*Y)+1.683]*HPD*DPY*0.047] + [0.000222*Y*60*HPD*DPY] + 10 • Y • 4,000
[(HPD/8)*DPY*29.67] + [(DPY/5)*29.67]
C= 56.416*Y+17,769
Chemical emulsion breaking, A = [(0.0512*Y+0.4524)*HPD*DPY*0.047] + [29.67*(HPD/8)*DPY] + [(DPY/5)*29.67] + Y • 860
coalescent plate separator [3.664*Y*HPD*DPY]
(gravity oil/water separator) '
[requires sulfuric acid, alum, C= 328.83 *Y +28,104
and polymer feed systems]
Dissolved air flotation See ultrafiltration for oil removal. Y < 4.42
[requires lime, feme sulfate, A = [(o.0728*Y+3.072)*HPD*DPY*0.047] + [0.0045*Y*60*HPD*DPY] + [29.67*HPD*DPY] + 4.42 • Y • 350
^ and polymer feed systems] [(DPY/5)*29.67] + [0.86*0.0003*Y*60*HPD*DPY] + [0.86*0.071*Y*60*HPD*DPY]
C= 1,125.4*Y+137,936
Ultrafiltration for oil A = [(0.71*Y+5.46)*HPD*DPY*0.047] + [0.4*Y+0.3] + [0.5*HPD*DPY*29.67] + [(DPY/5)*29.67] + Y • 406
removal [65.78*Y+193.46] + [(27,123*Y/24*365*60)*0.86*60*HPD*DPY]
C= 3,596*Y +235,146
Batch oil-emulsion breaking See dissolved air flotation. Y < 100
with gravity flotation A= [(0.65*Y+49.7)*HPD*DPY*0.047] + [HPD*DPY*29.67] + [(DPY/5)*29.67] + 100 • Y • 300
[requires sulfuric acid, alum, „ 022*Y*60*HPD*DPY*0 86]
and polymer feed systems] '
C= 17,204*Y + 2,000,000
Chromium reduction system, A = [2.4225*HPD*DPY*0.047] + [0.002608*Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] + Y • 410
sodium metabisulfite [(DPY/5)*29.67]
C= 261.7*Y + 24,249
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11.0 - Costs of Technology Bases for Regulations
Table 11-8 (Continued)
Equipment
Alkaline chlorination with
hypochlorite feed system
(for cyanide destruction)
Chelation breaking with
dithiocarbamate treatment
Chemical precipitation
[requires sulfuric acid,
systems]
Clarifier, slant-plate
(lamella)
Filtration, multimedia
Microfiltration system for
metals removal
Sludge thickening
A =
C =
A =
C =
A =
C =
A =
C =
A =
C =
C =
C =
A =
C =
A =
C =
A =
C =
A =
C =
Equation
[4.845*HPD*DPY*0.047] + [0.012418*Y*HPD*DPY*60] + [0.125*HPD*DPY*29.67] +
[(DPY/5)*29.67]
30,137*Yal866
[2.4225*HPD*DPY*0.047] + [0.000583 *Y*60*HPD*DPY] + [(HPD/8)*DPY*29.67] +
[(DPY/5)*29.67]
261.7*Y + 24,249
[0.932*HPD*DPY*0.047] + [(DPY/5)*29.67] + [(HPD/8)*DPY*29.67]
626.6*Y + 8,550
[((0.0571*Y)+0.0123)*HPD*DPY*0.047] + [(DPY/5)*29.67] + [(HPD/8)*DPY*29.67]
784.547*Y + 34,216
2*(DPY/5)*29.67
9,740
15,057 j
74.896*Y + 31,401
[[(0.0504*Y)+1.0139]*HPD*DPY*0.047] + [(HPD/8)*DPY*29.67] + [(DPY/5)*29.67]
240.85*Y + 27,269
[(0.3*Y+6.3)*HPD*DPY*0.047] + [3.4*Y] + [0.5*HPD*DPY*29.67] + [(DPY/5)*29.67] +
[184.2*Y+155.2]
1,728.3*Y + 69,337
[0.246*HPD*DPY*0.047] + [2*(DPY/5)*29.67]
74.306*Y*60 + 3,746
[3.7*HPD*DPY*0.047] + [2*(DPY/5)*29.67]
35.265*Y + 66,106
Range of Validity
1 • Y • 200
Y« 45
Y<5
5 • Y • 4,000
Y<2
2« Y< 10
10 • Y • 4,000
Y« 4,000
Y« 406
Y<42
42 • Y • 350
to
oo
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11.0 - Costs of Technology Bases for Regulations
Table 11-8 (Continued)
Equipment
Filter press, plate -arid-frame
Equation
A = [(60 + (30 * DPY * 2)) * NUM] + [FT3*DPY*7.48*1.95]
A = [(60 + (60 * DPY * 2)) * NUM] + [FT3*DPY*7.48*1.95]
A = [(60 + (90 * DPY * 2)) * NUM] + [FT3*DPY*7.48*1.95]
C= [1,658.8 *FT3] + 17,505
_
Range of Validity
CFT3 • 6
CFT3 • 12
CFT3 > 12
0.85 < FT3 • 76.5
to
VO
Variable Definitions:
C
A
Y
HPD
DPY
FT3
TANKVOL
CCFLOW
kW
CFT3
NUM
TSS
aAll costs are calculated in 1996 dollars.
= Direct capital costs (1996 dollars).
= Direct annual costs (1996 dollars).
= Influent equipment flow (gallons per minute).
= Operation hours per day.
= Days of operation per year.
= Daily cake volume (FT3) from all presses.
= Volume of countercurrent rinsing tank (gallons).
= Flow rate after countercurrent rinsing is supplied (gallons per minute).
= Kilowatts.
= Cake volume (FT3) per cycle per press (assume two cycles per day).
= Number of filter presses.
= Influent TSS concentration (mg/L).
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11.0 - Costs of Technology Bases for Regulations
11.4.2 Centrifugation and Pasteurization of Machining Coolant
EPA applied costs for centrifugation and pasteurization of machining coolant for
machining and grinding operations discharging water-soluble or emulsified coolant (listed in
Table 11-6). The treatment system used to estimate compliance costs consisted of a liquid-liquid
separation centrifuge for removal of solids and tramp oils and a pasteurization unit to reduce
microbial growth. The module added 50 percent excess capacity to each site's system to account
for fluctuations in production. The Agency based capital and annual costs on packaged systems
of different capacities. Flow rates of greater than 14 gallons per minute required multiple
systems. The various size systems included the following equipment:
• High-speed, liquid-liquid separation centrifuge;
Pasteurization unit; and
• Holding tanks for large volume applications.
Direct annual costs included operating and maintenance labor and materials,
energy costs, sludge and waste oil disposal costs, and a cost credit for water- and coolant-use
reduction. EPA estimated maintenance labor at one hour per week and operating labor at one
hour per shift.
Based on site visit and vendor information, EPA assumed that this technology can
reduce coolant discharge by 80 percent. The Agency based the amount of coolant and water
saved on the site recycling 80 percent of the coolant and discharging a 20 percent blowdown
stream to oil treatment. EPA assumed the coolant solution to be 95 percent water and 5 percent
coolant, based on site visit and vendor information.
11.4.3 Centrifugation of Painting Water Curtains
EPA applied costs for centrifugation of painting water curtains to painting water
curtain operations (listed in Table 11-6). The capital and annual costs include a centrifuge and a
holding tank large enough to hold flow for one hour.
Direct annual costs included operating and maintenance labor and materials,
energy costs, sludge disposal costs, and a cost credit for water-use reduction. EPA estimated
maintenance labor at one hour per week and operating labor at one hour per shift.
EPA assumed that the model site reused all water discharged from the
centrifugation system in painting operations, and the site contract hauled the sludge from the
system as a hazardous/nonhazardous sludge. EPA estimated contract hauling costs using the
average paint sludge hauling costs reported in the 1996 MP&M Detailed Surveys. Because
actual disposal costs will depend on site-specific conditions (e.g., paint type and spray-gun
cleaner requirements), EPA believes that the average cost for all paint sludge disposal reported in
the surveys, regardless of RCRA hazard classification, is a better estimate than using either the
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11.0 - Costs of Technology Bases for Regulations
costs for RCRA hazardous or RCRA nonhazardous paint sludges. (See Table 11-4 for contract
hauling costs and Section 11.4.4 below for more detailed information.)
11.4.4 Contract Hauling
The Agency estimated costs for off-site treatment and disposal of various types of
wastes generated on site. These waste types include:
Painting and paint stripping/solvent wastewater;
• Paint sludge;
Wastewater containing oil and grease and organic pollutants;
• Waste oils/sludges;
Chromium-bearing wastewater;
• Cyanide-bearing wastewater;
Chelated metal-bearing wastewater;
• General metal-bearing wastewater; and
Metal-bearing sludge.
Except for F006 hazardous waste, EPA estimated costs for off-site treatment and
disposal of each waste type in dollars per gallon of waste using averages of cost data provided in
the 1996 MP&M Detailed Surveys for contract hauling specific waste streams. The following
briefly summarizes how EPA applied these costs throughout the MP&M Design and Cost Model
(additional details are provided in the public record for this rulemaking);
EPA estimated a cost of $2.85 per gallon for contract hauling painting and
paint stripping wastewater for off-site treatment and disposal based on the
cost for contract hauling solvent-bearing wastewater as reported in the
1996 MP&M Detailed Surveys.
• EPA estimated a cost of $3.70 per gallon for contract hauling paint sludge
generated by the painting water curtain centrifugation system for
landfilling as a hazardous/nonhazardous waste based on the values
reported in the 1996 MP&M Detailed Surveys.
EPA estimated a cost of $1.33 per gallon for contract hauling wastewater
bearing oil and grease or other organic pollutants for off-site treatment
based on the values reported in the 1996 MP&M Detailed Surveys. EPA
used this estimate for sites at which the Cost Model determined contract
hauling to be less expensive than treatment on site (machining coolant
centrifugation and pasteurization system, chemical emulsion breaking and
gravity oil/water separation, dissolved air flotation, or ultrafiltration for oil
removal).
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11.0 - Costs of Technology Bases for Regulations
EPA estimated a cost of $0.86 per gallon for contract hauling waste oil
generated by machining coolant centrifugation and pasteurization,
chemical emulsion breaking and gravity oil/water separation, dissolved air
flotation, and ultrafiltration for oil removal based on the values reported in
the 1996 MP&M Detailed Surveys. Dissolved air flotation also generated
a waste sludge hauling cost, which was approximated using the waste oil
cost.
EPA estimated a cost of $3.51 per gallon for contract hauling hexavalent
chromium-bearing wastewater for off-site treatment based on the values
reported in the 1996 MP&M Detailed Surveys. EPA used this estimate for
sites at which the Cost Model determined contract hauling to be less
expensive than the chemical reduction of hexavalent chromium system.
EPA estimated a cost of $5.64 per gallon for contract hauling cyanide-
bearing wastewater for off-site treatment based on the values reported in
the 1996 MP&M Detailed Surveys. EPA used this estimate for sites at
which the Cost Model determined contract hauling to be less expensive
than the cyanide destruction system.
EPA estimated a cost of $1.40 per gallon for contract hauling chelated
metal-bearing wastewater for off-site treatment based on the values
reported in the 1996 MP&M Detailed Surveys. EPA used this estimate for
sites at which the Cost Model determined contract hauling to be less
expensive than the chemical reduction of chelated metals system.
EPA estimated a cost of $2.00 per gallon for contract hauling metal-
bearing wastewater for off-site treatment based on the values reported in
the 1996 MP&M Detailed Surveys. EPA used this estimate for sites at
which the Cost Model determined contract hauling to be less expensive
than the chemical precipitation and sedimentation system and the sludge
pressure filtration system.
• EPA estimated a cost of $1.95 per gallon for contract hauling metal-
bearing sludge, generated by the sludge pressure filtration system and the
machining coolant centrifugation and pasteurization system, for landfilling
as an F006 hazardous waste based on the value reported in Pollution
Prevention and Control Technology for Plating Operations (3).
11.4.5 Feed Systems
EPA estimated costs for generic feed systems. Where data were available, EPA
incorporated treatment-specific feed systems and dosages into the treatment system costs. If this
information was unavailable, EPA used literature information or engineering judgement to select
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11.0 - Costs of Technology Bases for Regulations
the dosages. The Agency used the following generic chemical dosages to estimate annual
operating and maintenance costs:
• Polymer feed system - 20 mg/L (3);
Continuous sodium hydroxide feed system -1,685 mg/L (3);
• Continuous hydrated lime feed system - 376 mg/L (3);
Continuous sulfuric acid feed system - 699 mg/L (3);
• Continuous ferric sulfate feed system - 74 mg/L (4);
Continuous aluminum sulfate (alum) feed system - 648mg/L (4); and
• Continuous calcium chloride feed system - 830 mg/L (3).
The discussions for treatment systems that use these generic feed system costs
and/or dosages refer back to this section. Capital and annual costs from these feed systems were
not reported individually in Cost Model outputs but were summed into the overall treatment
system capital and annual costs. The capital and annual costs for the following equipment were
included:
• Raw material storage tank;
Day storage tank with mixer;
• Chemical metering pumps;
pH controller; and
• Supporting piping and valves.
EPA developed low-flow polymer, sodium hydroxide, and sulfuric acid feed
modules with lower fixed capital and energy costs for flow rates less than 600 gallons per hour.
The alum feed system was given lower energy costs for systems below 350 gallons per hour.
Direct annual costs included operating and maintenance labor, energy costs, and chemicals. The
polymer module also included an annual maintenance material cost that was 10 percent of the
capital cost.
11.4.6 Chemical Emulsion Breaking and Gravity Oil/Water Separation
EPA estimated costs for chemical emulsion breaking and gravity oil/water
separation systems to separate and remove oil and grease and organic pollutants. The Agency
assumed that Model sites commingled all oil-bearing wastewater streams prior to treatment.
Table 11-6 lists these wastewater streams.
For chemical emulsion breaking systems, the module included capital and annual
costs for the following equipment:
Flow equalization tank;
• Two emulsion breaking tanks;
• Two mixers;
• Sulfuric acid feed system (see Section 11.4.5);
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11.0 - Costs of Technology Bases for Regulations
Polymer feed system (see Section 11.4.5);
• Alum feed system (see Section 11.4.5); and
Wastewater pumps.
Emulsion breaking was followed by oil removal using a coalescent plate
separator. For oil removal systems, the module included capital and annual costs for the
following equipment:
Feed pumps; and
• Oil/water separator.
Direct annual costs included operating and maintenance labor and materials,
energy costs, raw materials (e.g,. sulfuric acid, alum, polymer), and waste oil disposal costs.
Waste oil was contract hauled for off-site reclamation. EPA adjusted effluent flow rates for
removal of waste oil, which it estimated to be 7.1 percent of the influent flow, based on MP&M
survey data. Depending on the subcategory, EPA assumed model sites discharged the effluent
from this system either to surface water or a POTW or to the chemical precipitation and
sedimentation system. The Cost Model estimated costs associated with achieving the long-term
average effluent concentrations of oil and grease and other pollutants removed by chemical
emulsion breaking and gravity oil/water separation (see Section 10.3).
11.4.7 Dissolved Air Flotation
For the shipbuilding and railroad line maintenance subcategories, EPA estimated
costs for dissolved air flotation systems to separate and remove oil and grease, suspended solids,
and organic pollutants. The Agency assumed that model sites commingled all oil-bearing
wastewater streams prior to treatment. Table 11-6 lists these wastewater streams.
The module included capital and annual costs for the following equipment:
Flow equalization tank;
• Feed pumps;
Oil/water separator;
• Chemical treatment tank;
Lime feed system (see Section 11.4.5);
• Ferric sulfate feed system (see Section 11.4.5);
Polymer feed system (see Section 11.4.5);
• Dissolved air flotation system with pressure tank and programmable logic
controller (PLC);
• Oil storage tank; and
Final pH adjustment tank.
Direct annual costs included operating and maintenance labor and materials,
energy costs, raw materials (e.g., hydrated lime, ferric sulfate, polymer), and waste oil and sludge
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11.0 - Costs of Technology Bases for Regulations
disposal costs. EPA costed waste oil and sludge for contract hauling for off-site reclamation.
Hydrated lime and ferric sulfate were added to the treatment flow, while the polymer volume was
considered negligible. EPA adjusted effluent flow rates for removal of waste oil and sludge,
which were respectively estimated as 7.1 percent and 0.03 percent of the influent flow, based on
the MP&M survey data. EPA assumed model sites discharged effluent from this system either to
surface water or a POTW. The Cost Model estimated costs associated with achieving long-term
average effluent concentrations of oil and grease, total suspended solids, and other pollutants
treated by dissolved air flotation (see Section 10.3). Because dissolved air flotation systems are
not typically used for flow rates less than 265 gallons per hour, EPA costed model sites with
flows less than 265 gph for ultrafiltration for oil removal.
11.4.8 Ultrafiltration System for Oil Removal
EPA estimated costs for ultrafiltration systems to separate and remove oil and
grease, suspended solids, and organic pollutants. The Agency assumed that model sites
commingled all oil-bearing wastewater streams prior to treatment. Table 11-6 lists these
waste water streams.
The module included capital and annual costs for the following equipment:
Spiral-wound membrane filtration modules;
• Process and chemical tanks;
Steel skid;
• Recirculation tank;
Recirculation pump;
• Bag filter;
Fix-mounted cleaning system;
• Sludge pump; and
Electrical components (pH control/monitoring, temperature control, flow
meter, pressure gauges).
Flow rates greater than 406 gallons per minute required multiple systems.
Direct annual costs included operating and maintenance labor and materials,
energy costs, cleaning chemicals, membrane replacement, and waste oil disposal costs. The Cost
Model assumed model sites contract hauled waste oil for off-site reclamation. Depending on the
subcategory, EPA assumed the model sites discharged the effluent from this system either to
surface water or a POTW or to the chemical precipitation and sedimentation system. EPA
adjusted effluent flow rates for removal of waste oil, which was estimated as 5.2 percent of the
influent flow, based on MP&M survey data. The Cost Model estimated costs associated with
achieving long-term average effluent concentrations of oil and grease, total suspended solids, and
other pollutants treated by ultrafiltration (see Section 10.3).
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11.0 - Costs of Technology Bases for Regulations
11.4.9 Batch Oil Emulsion Breaking with Gravity Flotation
EPA estimated costs for batch oil emulsion breaking with gravity flotation
systems to separate and remove oil and grease, suspended solids, and organic pollutants. The
Agency assumed that model sites commingled all oil-bearing wastewater streams prior to
treatment.
Although this technology is not part of the MP&M technology options, EPA gave
treatment in place credit for chemical emulsion breaking and gravity oil/water separation to sites
with batch emulsion breaking with gravity flotation in place at baseline. The module included
capital and annual costs for the following equipment:
Polymer feed system (see Section 11.4.5);
• Sulfuric acid feed system (see Section 11.4.5);
Alum feed system (see Section 11.4.5);
• Two mechanically cleaning bar screens;
Three batch wastewater treatment tanks;
• Two segregated waste tanks;
Three skim and saleable oil storage tanks;
• Two oil cooking tanks;
Pumps;
• One air compressor;
Six mixers (segregation, saleable oil, and oil cooker tanks); and
• Ancillary equipment (pipes and valves, heat trace, controls, and PLC).
Direct annual costs included operating and maintenance labor, energy costs, raw
materials (e.g., polymer, sulfuric acid, alum), and waste oil disposal costs. EPA assumed model
sites contract hauled waste oil for off-site reclamation. Sulfuric acid and alum were added to the
treatment flow, while the polymer volume was considered negligible. The effluent from this
system was discharged to the chemical precipitation and sedimentation system. EPA adjusted
effluent flow rates for removal of waste oil, which was estimated as 2.2 percent of the influent
flow, based on MP&M survey data. The Cost Model estimated costs associated with achieving
long-term average effluent concentrations of oil and grease, total suspended solids, and other
pollutants removed by this technology. For baseline, EPA used this technology for flow rates
greater than 6,000 gallons per hour, whereas EPA used dissolved air flotation for flow rates
between 265 and 6,000 gallons per hour and ultrafiltration for oil removal for flow rates less than
265 gallons per hour.
11.4.10 Chemical Reduction of Hexavalent Chromium
EPA estimated costs for batch and continuous systems to reduce hexavalent
chromium to trivalent chromium prior to chemical precipitation and sedimentation. The Agency
assumed that model sites commingled all chromium-bearing wastewater streams prior to
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11.0 - Costs of Technology Bases for Regulations
treatment and that all chromium in the wastewater was in the hexavalent form. Table 11-6 lists
the chromium-bearing wastewater streams.
The Agency estimated costs for batch treatment for flow rates less than or equal
to 600 gallons per day, and continuous systems for flow rates greater than 600 gallons per day.
The module included capital and annual costs for the following equipment:
• Fiberglass reaction tank;
• Mixer;
• Sulfuric acid feed system;
Sodium metabisulfate feed system;
• Flow equalization tank;
Effluent pump; and
• pH and Oxidation-Reduction Potential (ORP) meters.
Direct annual costs included operating and maintenance labor and materials,
energy costs, and raw materials (e.g., sulfuric acid, sodium metabisulfite). EPA based flow
dependent costs on the volume of wastewater from chromium-bearing unit operations through
the system, before treatment chemicals were added to the flow. EPA assumed model sites
discharged effluent from this system to the chemical precipitation and sedimentation system.
Although hexavalent chromium does not have a long-term average effluent concentration from
chromium reduction systems (see Section 10.3), the Cost Model estimated costs associated with
reducing hexavalent chromium. EPA also assumed that all other pollutant concentrations
(including total chromium) remained unchanged in this treatment unit.
11.4.11 Cyanide Destruction
EPA estimated costs for batch and continuous alkaline chlorination systems to
destroy cyanide prior to chemical precipitation and sedimentation. The Agency assumed that
model sites commingled all cyanide-bearing wastewater streams prior to treatment. Table 11-6
lists these wastewater streams. EPA assumed that model sites did not send wastestreams that did
not contain cyanide to the cyanide destruction system.
The Agency estimated costs for batch treatment for flow rates less than or equal to
600 gallons per day, and continuous systems for flow rates greater than 600 gallons per day. The
cost model included capital and annual costs for the following equipment:
• Two reaction tanks (batch treatment uses a single tank, with the second
tank operating as a batch-holding tank);
• Mixers;
Sodium hydroxide feed system;
• Sulfuric acid feed system;
Sodium hypochlorite feed system;
• Effluent pumps; and
11-37
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11.0 - Costs of Technology Bases for Regulations
pH and ORP meters.
Direct annual costs included operating and maintenance labor and materials,
energy costs, and raw materials (e.g., sodium hydroxide, sulfuric acid, sodium hypochlorite).
EPA based flow dependent costs on the volume of wastewater from cyanide-bearing unit
operation through the system, before treatment chemicals were added to the flow. The Agency
assumed model sites discharged effluent from this system to the chemical precipitation and
sedimentation system. The Cost Model estimated costs associated with achieving the long-term
effluent concentrations of total and amenable cyanide from cyanide destruction systems. EPA
also assumed that all other pollutant concentrations remained unchanged in this treatment unit.
11.4.12 Chemical Reduction/Precipitation of Chelated Metals
EPA estimated costs for batch and continuous chemical reduction/precipitation of
chelated metal systems to break and precipitate electroless plating complexes (e.g., copper or
nickel complexes) prior to chemical precipitation and sedimentation. The Agency assumed that
model sites commingled all chelated-metal-bearing wastewater streams prior to treatment. Table
11-6 lists the chelated-metal-bearing wastewater streams.
The Agency costed batch treatment for flow rates less than or equal to 600 gallons
per day, and continuous systems for flow rates greater than 600 gallons per day. The cost model
included capital and annual costs for the following equipment:
• Fiberglass reaction tank;
• Mixer;
• Sulfuric acid feed system;
Dithiocarbamate feed system;
• Flow equalization tank;
Effluent pump; and
• pH and ORP meters.
Direct annual costs included operating and maintenance labor and materials,
energy costs, and raw materials (e.g., sulfuric acid, dithiocarbamate). EPA based flow dependent
costs on the volume of wastewater from chelated-metal-bearing unit operations through the
system, before treatment chemicals were added to the flow. The Agency assumed that model
sites discharged effluent from this system to the chemical precipitation and sedimentation
system. Based on analytical data for these systems, EPA assumed that concentrations of carbon
disulfide and dithiocarbamate increased across the system.
11.4.13 Chemical Precipitation
The Agency estimated costs for continuous chemical precipitation systems. EPA
costed low-flow systems for model sites with influent flow rates less than or equal to 300 gallons
per hour. EPA assumed that the model sites commingled all MP&M wastewater generated for
11-38
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11.0 - Costs of Technology Bases for Regulations
treatment by this technology, except for wastewater from the Oily Wastes, the Shipbuilding Dry
Dock and the Railroad Line Maintenance subcategories, and except for solvent-bearing
wastewater which EPA costed for off-site disposal.
The module included capital and annual costs for the following equipment:
Sulfuric acid feed system (see Section 11.4.5);
• Polymer feed system (see Section 11.4.5);
Caustic feed system (see Section 11.4.5);
• Equalization tank;
Rapid-mix tank for precipitation;
• Flocculation tank;
Final pH-adjustment tank;
• System feed pumps; and
Rapid and flocculation mixers.
The module assumed that the total suspended solids leaving the chemical
precipitation system was equivalent to the sum of influent total suspended solids and the
dissolved solids that are converted to suspended solids. The approach for calculating suspended
solids from dissolved solids is documented in the public record for this rulemaking. Additional
flow from treatment chemical addition was considered negligible. EPA designed the Cost Model
to include recycled water from the sludge thickener and filter press. The Agency assumed that
model sites discharged effluent from this system to either clarification or microfiltration. Direct
annual costs included operating and maintenance labor, energy costs, and raw materials (e.g.,
sulfuric acid, polymer, caustic).
11.4.14 Slant-Plate Clarifier
The Agency estimated costs for slant-plate (lamella) clarifier systems. EPA
costed low-flow systems for model sites with influent flow rates less than or equal to 600 gallons
per hour. This system treated effluent from the chemical precipitation system.
The module included capital and annual costs for the following equipment:
Slant-plate clarifier; and
• One-time 80-hour training cost for operators to meet MP&M clarifier
limits instead of the baseline 40 CFR Part 433 Metal Finishing effluent
guideline limits.
The Cost Model estimated costs associated with achieving long-term average
effluent concentrations for all pollutants treated by chemical precipitation with clarification (see
Section 10.3). EPA calculated the amount of sludge generated by this system using site-specific
influent pollutant concentration data for the commingled wastewater. The Agency assumed the
sludge to be 3 percent solids and costed for discharge to a sludge-thickening tank. EPA assumed
11-39
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11.0 - Costs of Technology Bases for Regulations
that model sites discharge the effluent from this system to surface water or a POTW. Direct
annual costs included maintenance labor and materials. EPA considered operating labor as part
of chemical precipitation and accounted for pumps in the chemical precipitation and the sludge-
thickening modules.
11.4.15 Multimedia Filtration
The Agency estimated costs for a multimedia filter to continuously remove
filterable suspended solids. The system was designed as a polishing step for effluent from the
clarifier. Although EPA did not include this technology in the MP&M technology options, it
gave treatment in place credit to sites with multimedia filters in place.
The module included capital and annual costs for the following equipment:
• Multimedia filter skid;
• Holding tank for clarifier effluent (clearwell); and
Media filter feed pump.
EPA assumed pollutant concentrations in the effluent from these systems to be
equal to the clarifier long-term average concentrations except for total suspended solids, which
was reduced 35 percent across this system based on MP&M sampling data. The Agency
assumed filter backwash to be 1.2 percent of the influent flow to the chemical precipitation unit.
EPA assumed model sites discharged filtrate from this system to surface water or a POTW.
Direct annual costs included operating and maintenance labor and energy costs. EPA
incorporated waste disposal costs from solids into the filter press module at sites operating
multimedia filters.
11.4.16 Microfiltration for Solids Removal
The Agency estimated costs for continuous chemical precipitation systems
followed by microfiltration for solids separation.
The module included capital and annual costs for the following equipment:
Tubular membrane filtration modules;
• Carbon steel skid;
Recirculation tank;
• Recirculation pump;
Air back pulse system;
• Cleaning system;
Sludge pump; and
• All associated instruments and controls.
Flow rates greater than 406 gallons per minute required multiple systems.
11-40
-------
11.0 - Costs of Technology Bases for Regulations
The Cost Model estimated costs associated with achieving long-term average
effluent concentrations for all pollutants treated by chemical precipitation followed by
microfiltration systems (see Section 10.3). EPA calculated the amount of sludge generated by
this system using site-specific influent pollutant concentration data for the commingled
wastewater. The Agency assumed the sludge to be 3.2 percent solids and costed for discharge to
a sludge-thickening tank. EPA assumed model sites discharged the effluent from this system to
surface water or a POTW. Direct annual costs included operating and maintenance labor and
materials (e.g., replacement membranes, cleaning chemicals), and energy costs.
11.4.17 Sludge Thickening
The Agency estimated costs for sludge thickening by gravity settling for the
sludge discharged from the chemical precipitation and sedimentation system. EPA assumed the
sludge-thickening system to discharge 60 percent of influent flow as sludge, thus increasing the
solids content of the sludge from 3 percent to 5 percent for clarifier effluent and from 3.2 percent
to 5.3 percent for microfiltration effluent prior to further dewatering in the sludge pressure
filtration system. The module included capital and annual costs for the following equipment:
Sludge-thickening unit (package system); and
• Clarified water return pump.
EPA costed for model sites to discharge the sludge from this system to the sludge
pressure filtration system. The Agency assumed model sites returned the remaining 40 percent of
influent flow back to the chemical precipitation system as supernatant and it included this flow in
its design. Direct annual costs included operating and maintenance labor and energy costs.
11.4.18 Sludge Pressure Filtration
The Agency estimated costs for the number of plate-and-frame filter presses
needed to increase the solids content of the sludge from approximately 5 percent to 35 percent
prior to contract hauling for off-site disposal. The module included capital and annual costs for
the following equipment:
• Recessed plate or plate-and-frame filter press; and
Two double-diaphragm sludge pumps.
Direct annual costs included operating and maintenance labor and sludge disposal
costs. The Cost Model assumes model sites discharge the filtrate from this system to the
chemical precipitation and sedimentation system.
11-41
-------
11.0 - Costs of Technology Bases for Regulations
11.5 References
1. U.S. Environmental Protection Agency. Economic. Environmental & Benefits
Analysis of the Proposed Metal Products & Machinery Rule. EPA-821-B-00-008,
December 2000.
2. —Means Building Construction Cost Data. 56th Annual Edition, 1998, page 594.
Historical Cost Indexes.
3. Cushnie, George C., CAI Engineering (prepared for NCMS/NAMF). Pollution
Prevention and Control Technology for Plating Operations.
4. U.S. Environmental Protection Agency. MP&M sampling data.
11-42
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11.0 - Costs of Technology Bases for Regulations
Industrial process
wastewater streams
Is the
current option
being analyzed
2, 4, 6, 8,
or 10?*
Discharge to surface
water or POTW
' See Section 9 for descriptions of the 10 technology options.
Figure 11-1. Relationship Between In-Process and End-of-Pipe Technologies and Practices
11-43
-------
11.0 - Costs of Technology Bases for Regulations
Individual
process wastewater
streams
Is this
rinse stream
applicable for
flow
reduction?
Is this a
wastewater
Countercurrent
cascade rinse
Discharge
to end-of-pipe
treatment
system
No
Zero discharge
to end-of-pipe
treatment
system
Discharge
to end-of-pipe
treatment
^v system J
No
inse
•earn?
,/
\
> W\ v/WMiaiii
/ \ mach
/ \ cool
Yes
r
Combine
paint
curtain
wastewater
streams
\
r
Centrifugation
of
painting
water
curtains
\
r
\
pan u ui
ining
ant? /
r
Combine
machining
coolant
wastewater
streams
\
r
Centrifugation
and
pasteurization
of machining
coolants
\
4
/
^
r
Figure 11-2. Components of Total Capital Investment
11-44
-------
11.0 - Costs of Technology Bases for Regulations
/'vVastewater streams frorrix
( individual processes or )
in-process controls
oes the
wastewater
contain chromium
cyanide, chelated
metal, oil, or
solvent?
solvent-bearing
Contract haul
for off-site
treatment
and disposal
chelated metals
Oil
reclaim/
disposal
Discharge to
H surface water
orPOTW
Contract haul
for off-site
disposal
Figure 11-3. Logic Used to Apply End-of-Pipe Technologies and Practices for the Following
Subcategories: General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing, Printed
Wiring Board, and Steel Forming and Finishing
11-45
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11.0 - Costs of Technology Bases for Regulations
/vVastewater streams frorn\
( individual processes or )
\^ in-process controls ^/
What Railroad line maintenance
Oily wastes SUDCategorv or shipbuilding dry dock
Chemical emulsion
breaking (polymer,
alum, sulfuric acid)
Discharge to
surface water
or POTW
* See Section 9 for descriptions of the 10 technology options.
Figure 11-4. Logic Used to Apply End-of-Pipe Technologies
and Practices for the Following Subcategories: Oily Waste,
Railroad Line Maintenance, and Shipbuilding Dry Dock
11-46
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12.0 - Pollutant Loading and Reduction Estimates
12.0 POLLUTANT LOADING AND REDUCTION ESTIMATES
This section describes EPA's estimation of industry pollutant loadings and
pollutant reductions for each MP&M technology option described in Section 9.0. The Agency
estimated pollutant loadings and reductions from MP&M sites to evaluate loadings to surface
waters and publicly owned treatment works (POTWs), and to assess the effectiveness of each
MP&M technology option in reducing these loadings. An assessment of the water-quality
impacts and benefits associated with the reduced pollutant loadings from MP&M facilities as
estimated in this section is presented in the report "Economic, Environmental, and Benefits
Assessment of the Proposed MP&M Rule." This report is located in the public record for this
proposal.
In estimating the pollutant loadings, EPA assumed that all nondetected pollutants
of concern are present at the detection limit. EPA did not use the same assumptions in all cases
when calculating limits (see Section 10.0). Throughout this section, the terms "sampling point"
and "sample" are used as defined below:
Sampling Point. A sampling point is the physical location at which samples are
collected. Example sampling points include a wastewater treatment influent
stream, an electroplating bath, or a cleaning rinse.
Sample. A sample is the unique volume of wastewater collected for analysis at a
sampling point. A sample can include several different aliquots collected for
analysis of multiple parameters. Each sample represents a unique period of time.
EPA typically collected multiple samples from sampling points that represented
flowing wastestreams (e.g., wastewater treatment systems, rinses).
Figure 12-1 summarizes the steps used to estimate the MP&M pollutant loadings
and reductions for each technology option. These steps are described in Sections 12.1 and 12.2.
Section 12.1 describes the calculation of pollutant concentrations for each unit operation.
Section 12.2. presents the results of the raw, baseline, and post-compliance pollutant loading and
reduction calculations for the industry.
12-1
-------
Collect analytical data from MP&M field
sampling. QA/QC procedures have been applied
to all samples.
12.0 - Pollutant Loading and Reduction Estimates
Identify Available
Analytical Data from
Field Sampling
to
to
Average multiple samples for
each sampling point and
duplicate samples.
Identify unit operation, base
metal/metal applied, and
pollutant concentration for each
pollutant of concern for each
unit operation sampling point.
Calculate Pollutant
Concentrations for
each Sampling Point
Average across all sampled
sites for each sampled unit
operation.
Estimate Pollutant
Concentrations for
each Unit Operation
Transfer pollutant loadings to
unit operations in the survey
data without analytical data
from field sampling for each
unit operation a site reported.
Multiply by annual flow for each raw
wastewater stream at each model site, apply
weighting factors to estimate national
industry loadings across all model sites.
Subtract estimated pollutant
loadings removed by each MP&M
technology option using
technology-specific treatment
effectiveness concentrations
transferred from sampled BAT
sites. For indirect dischargers,
Estimate Industry
Raw Wastewater
Pollutant Loadings
•^
Subtract estimated pollutant
loadings removed by technology
in nla^fi at e,ach tnnHftl site
Estimate Industry
Baseline Pollutant
Loadings
reduce the pollutant removals by
the corresponding POTW percent
removal.
Estimated Option-
Specific Industry
Pollutant
Reductions
Figure 12-1. Estimation of MP&M Pollutant Loadings and Reductions
-------
12.0 - Pollutant Loading and Reduction Estimates
12.1 Estimation of Unit Operation Pollutant Concentrations
EPA used data collected during the MP&M sampling program to estimate
pollutant concentrations in wastewater streams from each of the MP&M unit operations reported
by questionnaire respondents as generating wastewater. EPA developed these estimates for each
pollutant of concern (see Section 7.0). These data are included in Sampling Episode Reports
(SERs) in the administrative record for this rulemaking. To develop the unit operation
concentrations, EPA calculated pollutant concentrations for each sampling point (Section 12.1.1),
then calculated the pollutant concentrations for each unit operation (Section 12.1.2).
The first step in estimating pollutant concentrations for each unit operation was to
identify unit operations for which pollutant concentrations depend on metal type. This was
important when transferring concentrations across unit operations (Section 12.1.2). EPA
reviewed the unit operation descriptions and analytical data to identify those unit operations for
which pollutant concentrations would be most dependent on metal type processed. While most
MP&M unit operations are somewhat dependent on metal type processed, EPA identified two
operations (and their associated rinses) for which pollutant concentrations are heavily dependent
on metal type: electroplating and electroless plating. In both of these operations and associated
rinses, pollutant concentrations depend on the metal type being applied in the operation. For
example, chromium electroplating operations and rinses contain higher concentrations of
chromium than other metals, while electroless nickel plating operations and rinses contain higher
concentrations of nickel than other metals.
12.1.1 Calculate Pollutant Concentrations for Each Sampling Point
EPA developed a pollutant profile (i.e., concentrations for each pollutant of
concern) for each sampling point. EPA used the following approach to calculate pollutant
concentrations for each sampling point:
• Average duplicate sample concentrations. As discussed in Section 4.0,
EPA collected duplicate samples at many sampling points as a quality
control measure. EPA averaged the concentrations for the original and
duplicate samples.
• Average multiple sample concentrations for each sampling point. At
sampling points representing flowing wastewater streams (e.g., rinses),
EPA typically collected multiple samples over time. EPA collected these
samples to account for variability over time of the discharges from these
streams. EPA averaged the concentrations for the samples collected on
multiple days at the same sampling point. For example, if EPA collected
three one-day composite samples for acid treatment rinsing at the same
sampling point, it averaged the concentrations for each pollutant on each
of the three days to estimate the pollutant concentration for the sampling
point.
12-3
-------
12.0 - Pollutant Loading and Reduction Estimates
12.1.2 Estimate Pollutant Concentrations for Each Unit Operation
EPA estimated pollutant concentrations for each unit operation reported in the
MP&M detailed surveys. For electroplating and electroless plating operations, EPA estimated
concentrations for each unit operation and metal type combination reported in the surveys. EPA
used the following steps to estimate the pollutant concentrations:
• Identify all unit operations reported in the detailed surveys. EPA queried
the MP&M detailed survey database to identify all unit operations reported
as discharging wastewater, as well as all unit operation and metal type
combinations (based on applied metal) for electroplating and electroless
plating. EPA considered unit operations performed at facilities in the
Non-chromium Anodizing subcategory to be unique from unit operations
performed in other subcategories because the non-chromium anodizing
process primarily aluminum and perform a limited subset of unit
operations, as described in Section 6.2.4. Therefore, EPA developed
unique pollutant concentrations for operations performed at Non-
chromium Anodizing facilities.
• Estimate pollutant concentrations for each unit operation for which
sampling analytical data are available. EPA averaged the pollutant
concentrations for each unit operation and each unit operation and metal
type combination (for electroplating and electroless plating) across sites.
For example, EPA averaged the site-level pollutant concentrations for all
acid cleaning operations.
• Transfer data to unit operations for which sampling data are not
available. The final step in estimating unit operation pollutant
concentrations consisted of transferring data to unit operations for which
EPA did not collect sampling data. EPA transferred pollutant
concentrations from unit operations expected to have similar wastewater
characteristics based on process considerations, including the following:
the purpose of the unit operation (e.g., metal removal, contaminant
removal); the purpose of the process water use (e.g., contact cooling water,
cleaning solution, rinsewater); and the wastewater flow per unit of
production as reported in the MP&M surveys. Supporting documentation
for all data transfers of unit operation pollutant concentrations is contained
in the administrative record for this rulemaking.
12.2 Calculation of Industry Pollutant Loadings and Reductions
EPA estimated the pollutant loadings for each pollutant of concern for each
wastewater discharging unit operation at each model site (model site development is described in
Section 11.2). EPA estimated industry-wide raw wastewater pollutant loadings, baseline
12-4
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12.0 - Pollutant Loading and Reduction Estimates
pollutant loadings, and option-specific loadings for each MP&M technology option as described
in Sections 12.2.1 through 12.2.3. EPA subtracted the option-specific post-compliance pollutant
loading estimates from the baseline loadings to estimate pollutant reductions for each option.
12.2.1 Industry Raw Wastewater Pollutant Loadings
Industry raw wastewater pollutant loadings represent the industry pollutant
loadings before removal by treatment technologies currently in place at MP&M sites. EPA used
the following steps to estimate the raw wastewater loadings:
• Estimate site-specific raw wastewater pollutant loadings. For each
wastewater discharging unit operation at each model site, EPA multiplied
the unit operation concentrations by its wastewater flow rate (as reported
in the questionnaire) to obtain a mass loading. EPA then summed the
loadings for each pollutant across all unit operations performed at each
model site to develop a site-specific raw wastewater pollutant loading.
• Estimate industry-wide raw wastewater pollutant loadings. EPA
multiplied the site-specific raw wastewater pollutant loadings for each
pollutant of concern by the corresponding site-specific statistically derived
weighting factors discussed in the report "Statistical Summary for the
MP&M Industry Surveys." EPA summed the weighted loadings across all
sites in each subcategory to develop subcategory-specific raw wastewater
pollutant loadings. EPA also summed the weighted loadings across all
sites to develop industry-wide raw wastewater pollutant loadings.
Tables 12-1 and 12-2 present the results of the estimation for industry raw
wastewater annual pollutant loadings by subcategory for direct and indirect dischargers,
respectively.
12.2.2 Industry Baseline Pollutant Loadings
Industry baseline pollutant loadings represent the industry pollutant loadings after
accounting for pollutant removals by technologies already in place at MP&M sites. Section 11.0
describes the assessment of technology in place for each model site. EPA used the following
steps to estimate the baseline pollutant loadings:
• Estimate site-specific baseline pollutant loadings. EPA performed a
baseline run of the MP&M Design and Cost Model to estimate site-
specific baseline pollutant loadings for each model site. The baseline run
used the technologies in place at each site rather than the MP&M
technology options. EPA estimated the site-specific baseline loadings as
the pollutants being discharged after the application of the treatment
technologies currently in place at model sites.
12-5
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12.0 - Pollutant Loading and Reduction Estimates
• Estimate industry-wide baseline pollutant loadings. EPA multiplied the
site-specific baseline pollutant loadings for each pollutant of concern by
the corresponding site-specific statistically-derived weighting factors
discussed in the report "Statistical Summary for the MP&M Industry
Surveys." EPA summed the weighted loadings across all sites in each
subcategory to develop subcategory-specific baseline pollutant loadings.
EPA also summed the weighted loadings across all sites to develop
industry-wide baseline pollutant loadings.
Tables 12-1 and 12-2 present the results of the estimation for industry baseline
pollutant loadings by subcategory for direct and indirect dischargers, respectively.
12.2.3 Option-Specific Industry Pollutant Loadings and Pollutant Reductions
Option-specific pollutant loadings (i.e., post-compliance pollutant loadings for
each technology option) represent the total industry pollutant loadings after the application of
each MP&M technology option. Option-specific pollutant reductions represent the total industry
pollutant removals for each technology option. EPA estimated option-specific loadings and
reductions as follows:
• Estimate site-specific, option-specific pollutant loadings. EPA used the
MP&M Design and Cost Model (see Section 11.0) to estimate pollutant
loadings for each site for each technology option.
• Estimate site-specific, option-specific pollutant removals. EPA estimated
the option-specific pollutant removals as the difference between the site-
specific baseline pollutant loadings and the option-specific pollutant
loadings. For indirect dischargers, EPA then reduced the site-specific,
option-specific pollutant removals by their corresponding POTW percent
removal (see Table 12-3) to account for treatment that will occur at the
POTW.
• Estimate industry-wide, option-specific pollutant loadings and removals.
For each option, EPA multiplied the site-specific pollutant loadings and
removals (accounting for POTW removals for indirect dischargers) for
each pollutant of concern by the corresponding site-specific statistically-
derived weighting factors discussed in the report "Statistical Summary for
the MP&M Industry Surveys." EPA summed the weighted loadings and
removals across all sites in each subcategory to develop subcategory-
specific pollutant loadings and removals. EPA also summed the weighted
loadings and removals across all sites to develop industry-wide pollutant
loadings and reductions.
12-6
-------
12.0 - Pollutant Loading and Reduction Estimates
Tables 12-2 and 12-3 present the estimated Selected Option pollutant loadings by
subcategory for direct and indirect dischargers, respectively. Tables 12-4 and 12-5 present the
estimated pollutant removals by the Selected Option for direct and indirect dischargers,
respectively. Tables 12-6 through 12-20 present the top pollutants removed (in toxic pound
equivalents) by the Selected Option by subcategory for direct and indirect dischargers.
12-7
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12.0 - Pollutant Loading and Reduction Estimates
Table 12-1
Summary of Annual Pollutant Loadings for MP&M Direct Dischargers by Subcategory
Subcategory
General Metals
Metal Finishing
Job Shops
Non-Chromium
Anodizing (e)
Printed Wiring
Board
Steel Forming and
Finishing
Oily Wastes
Railroad Line
Maintenance (f)
Shipbuilding Dry
Dock
Total
No. of
Sites
3,784
16
-
12
43
912
34
6
Industry Raw Wastewater Pollutant Loadings (a)
(Ibs-eq/yr)
6,521,910
34,622
-
249,276
3,327,437
81,407
2,145
27,903
(Ibs/yr)
Priority &
Nonconventional
Metals/
Organics(d)
46,976,587
151,584
-
1,167,185
23,205,748
1,639,048
187,605
3,393,475
TSS/Oil and
Grease
(as HEM)
115,775,867
261,057
-
729,629
11,374,652
12,343,318
990,500
8,946,211
Baseline Pollutant Loadings (b)
(Ibs-eq/yr)
1,248,018
15,672
-
59,340
124,972
21,060
1,128
1,815
(Ibs/yr)
Priority &
Nonconventional
Metals/
Organics(d)
10,653,897
56,102
-
278,370
941,572
730,372
55,611
94,772
TSS/Oil
and Grease
(as HEM)
19,050,051
38,319
-
362,431
1,276,363
1,378,666
70,158
8,515,131
Selected Option Pollutant Loadings (c)
(Ibs-eq/yr)
133,429
1,608
-
11,922
208,877
22,535
1,267
1,896
(Ibs/yr)
Priority &
Nonconventional
Metals/
Organics(d)
1,420,008
11,992
-
83,015
630,756
661,310
179,157
95,936
TSS/Oil
and Grease
(as HEM)
1,161,143
10,776
-
73,770
38,891,453
356,912
16,021
102,502
to
oo
Source: MP&M pollutant loadings.
(a) These raw loads do not reflect treatment currently in place.
(b) These baseline loads reflect treatment currently in place.
(c) These loads reflect the load after the implementation of the MP&M technology basis for each Subcategory.
(d) Does not include sodium, calcium, total dissolved solids, and potassium.
(e) EPA's data collection efforts did not identify any direct discharging non-chromium anodizing facilities.
(f) The baseline and the Selected Option pollutant loadings for BOD5 for Railroad Line Maintenance is 59,814 and 57,150 Ibs/yr, respectively.
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-2
Summary of Annual Pollutant Loadings for MP&M Indirect Dischargers by Subcategory
(a)
Subcategory
General Metals
Metal Finishing
Job Shops
Non-Chromium
Anodizing
Printed Wiring
Board
Steel Forming and
Finishing
Oily Wastes
Railroad Line
Maintenance
Shipbuilding Dry
Dock
Total
No. of
Sites
26,195
1,515
191
621
111
28,514
799
6
Industry Raw Wastewater Pollutant Loadings (b)
(Ibs-eq/yr)
116,275,842
20,417,884
122,359
5,732,973
1,248,907
1,002,116
3,794
397
(Ibs/yr)
Priority &
Nonconventional
Metals/ Organics
(f>
555,129,426
38,428,372
869,757
21,773,732
9,120,891
17,206,229
40,084
38,542
TSS/Oil and
Grease
(as HEM)
737,700,419
15,780,889
1,718,224
26,175,775
6,328,042
75,298,418
10,463,731
13,482
Baseline Pollutant Loadings (c)
(Ibs-eq/yr)
23,804,767
5,598,845
117,647
2,727,103
400,524
496,626
1,712
257
(Ibs/yr)
Priority &
Nonconventional
Metals/ Organics
(f)
155,478,167
12,741,874
808,018
9,103,518
2,667,746
13,396,099
14,759
25,984
TSS/Oil
and Grease
(as HEM)
398,844,708
10,406,023
1,473,802
20,019,186
1,045,957
24,366,355
71,136
5,356
Selected Option Pollutant Loadings (d,e)
(Ibs-eq/yr)
1,241,465
118,988
NR
149,959
104,606
506,597
NR
NR
(Ibs/yr)
Priority &
Nonconventional
Metals/ Organics
(f)
11,732,601
1,015,185
NR
1,226,487
336,249
3,333,132
NR
NR
TSS/Oil and
Grease
(as HEM)
11,082,451
813,455
NR
941,657
22,531,113
4,822,848
NR
NR
to
Source: MP&M pollutant loadings.
NR - Not regulated. EPA is not proposing to regulate these sites under the MP&M rule.
(a) These loads do not reflect removals by publicly owned treatment works (see Table 12-4 for incorporation of POTW removals).
(b) These raw loads do not reflect treatment currently in place.
(c) These baseline loads reflect treatment currently in place.
(d) These loads include only those for the regulated sites; this accounts for 3,056 General Metals facilities discharging greater than 1 MGY and 226 Oily Wastes
facilities discharging greater than 2 MGY.
(e) These loads reflect the load after the implementation of the MP&M technology basis for each Subcategory.
(f) Does not include sodium, calcium, total dissolved solids, and potassium.
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-3
Publicly Owned Treatment Works (POTW) Removal Percents For Each
MP&M Pollutants of Concern
Chemical Name
1,1,1 -Trichloroethane
1 , 1 -Dichloroethane
1, 1-Dichloroethene
1,4-Dioxane
l-Bromo-2-Chlorobenzene
l-Bromo-3-Chlorobenzene
1 -Methy Ifluorene
1 -Methy Iphenanthrene
2,4-Dimethylphenol
2,4-Dinitrophenol
2,6-Dinitrotoluene
2-Butanone
2-Hexanone
2-Isopropylnaphthalene
2-Methylnaphthalene
2-Nitrophenol
2-Propanone
3,6-Dimethylphenanthrene
4-Chloro-3 -Methy Iphenol
4-Methyl-2-Pentanone
4-Nitrophenol
Acenaphthene
Acetophenone
Acrolein
Alpha-Terpineol
Aluminum
Amenable Cyanide
Ammonia As Nitrogen
Aniline
POTW
Removal
Percent
90.45
70
77.51
45.8
77.32
77.32
84.55
84.55
77.51
77.51
77.51
96.6
77.32
77.32
28
26.83
83.75
84.55
63
87.87
77.51
98.29
95.34
77.51
94.4
91.36
57.41
38.94
93.41
Source30
a
a
c
b
c
c
b
b
c
c
c
b
c
c
b
a
b
b
b
b
c
a
b
c
b
a
c
a
b
12-10
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-3 (Continued)
Chemical Name
Anthracene
Antimony
Arsenic
Barium
Benzoic Acid
Benzyl Alcohol
Beryllium
Biphenyl
Bis(2-Ethylhexyl) Phthalate
Bod 5 -Day (Carbonaceous)
Boron
Butyl Benzyl Phthalate
Cadmium
Calcium
Carbon Bisulfide
Chemical Oxygen Demand (COD)
Chloride
Chlorobenzene
Chloroethane
Chloroform
Chromium
Cobalt
Copper
Cyanide
Di-N-Butyl Phthalate
Di-N-Octyl Phthalate
Dibenzofuran
Dibenzothiophene
Dimethyl Phthalate
Diphenyl Ether
Diphenylamine
Ethylbenzene
POTW
Removal
Percent
77.51
66.78
65.77
15.98
80.5
78
71.66
96.28
59.78
89.12
30.42
81.65
90.05
8.54
84
81.3
57.41
96.37
77.51
73.44
80.33
6.11
84.2
70.44
84.66
68.43
77.32
84.68
77.51
77.32
77.32
93.79
Source30
c
a
a
a
b
b
c
b
a
a
a
a
a
a
b
a
c
a
c
a
a
a
a
a
a
a
c
b
c
c
c
a
12-11
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-3 (Continued)
Chemical Name
Fluoranthene
Fluorene
Fluoride
Gold
Hexanoic Acid
Hexavalent Chromium
Iron
Isobutyl Alcohol
Isophorone
Lead
M+P Xylene
M-Xylene
Magnesium
Manganese
Mercury
Methyl Methacrylate
Methylene Chloride
Molybdenum
N,N-Dimethylformamide
N-Decane
N-Docosane
N-Dodecane
N-Eicosane
N-Hexacosane
N-Hexadecane
N-Nitrosodimethylamine
N-Nitrosodiphenylamine
N-Nitrosopiperidine
N-Octacosane
N-Octadecane
N-Tetracosane
N-Tetradecane
POTW
Removal
Percent
42.46
69.85
61.35
32.52
84
57.41
81.99
28
77.51
77.45
77.32
95.07
14.14
35.51
71.66
99.96
54.28
18.93
87
9
88
95.05
92.4
71.11
71.11
77.51
90.11
77.32
71.11
71.11
71.11
71.11
Source30
a
a
c
b
c
a
b
c
a
c
b
a
a
c
b
a
a
b
b
b
b
b
b
b
c
b
c
b
b
b
b
12-12
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-3 (Continued)
Chemical Name
N-Triacontane
Naphthalene
Nickel
O+P Xylene
O-Cresol
O-Xylene
Oil And Grease (As HEM)
P-Cresol
P-Cymene
Phenanthrene
Phenol
Phosphorus
Pyrene
Pyridine
Selenium
Silver
Sodium
Styrene
Sulfate
Tetrachloroethene
Thallium
Tin
Titanium
Toluene
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Organic Carbon (TOC)
Total Petroleum Hydrocarbons (As SGT-HEM)
Total Phosphorus
Total Recoverable Phenolics
Total Sulfide
Total Suspended Solids
POTW
Removal
Percent
77.32
94.69
51.44
65.4
52.5
77.32
86.08
71.67
99.79
94.89
95.25
32.52
83.9
95.4
34.33
88.28
2.69
93.65
84.61
84.61
71.66
42
91.82
96.18
8
57.41
70.28
57.41
57.41
57.41
57.41
89.55
Source30
c
a
a
b
b
c
a
b
b
a
a
c
b
b
b
a
a
b
b
a
c
a
a
a
b
c
a
c
c
c
c
a
12-13
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-3 (Continued)
Chemical Name
Trichloroethene
Trichlorofluoromethane
Tripropyleneglycol Methyl Ether
Vanadium
Weak-Acid Dissociable Cyanide
Yttrium
Zinc
POTW
Removal
Percent
77.51
77.32
52.4
9.51
57.41
32.52
79.14
Source30
c
c
b
a
c
c
a
Note: See public record for further detail for the sources.
a November 5, 1999 Updated 50-POTW Study. Influent Concentration lOxML, 5xML, then 20 ppb.
b RREL Database. Compiled for the CWT effluent guideline or the 1995 Phase I Proposal.
0 Average POTW removals calculated by classification code from sources a and b.
12-14
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-4
Summary of Annual Pollutant Reductions for MP&M Direct Dischargers by Subcategory
(a,b)
Subcategory
General Metals
Metal Finishing Job Shops
Non-Chromium Anodizer
Printed Wiring Board
Steel Forming and Finishing
Oily Wastes
Railroad Line Maintenance
Shiubuilding Dry Dock
Total No. of
Regulated
Sites
3,795
16
NA(d)
12
43
912
34
6
Baseline Pollutant Loadings
Ib-eq/yr
1,248,018
15,672
-
59,340
124,972
21,060
1,128
1.815
Ibs/yr (c)
29,703,949
94,422
-
640,801
2,217,935
2,109,039
125,770
8.609.903
Pollutant Removals by Selected Option
Ib-eq/yr
1,123,797
14,377
-
48,366
85,070
9,899
154
111
Ibs/yr (c)
27,224,783
71,766
-
485,395
1,448,450
1,441,671
57,538
8.453.293
% Reduction from
Baseline (Ib-eq/yr)
90.0%
91.7%
-
81.5%
68.1%
47.0%
13.6%
6.1%
to
Source: MP&M pollutant loadings.
(a) Pollutant loadings and removal estimates presented in this table will not equate with those presented in the Cost-Effectiveness Analysis and the EEBA. The
estimates in those documents do not include pollutant loadings from facilities that are projected to close in the baseline.
(b) See Tables 12-6 through 12-12 for pollutant-specific removals by Subcategory.
(c) Does not include sodium, calcium, total dissolved solids, chemical oxygen demand, and potassium.
(d) EPA's data collection efforts did not identify any direct discharging non-chromium anodizing facilities.
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-5
Summary of Annual Pollutant Reductions for MP&M Indirect Dischargers by Subcategory
(a,b)
Subcategory
General Metals
Metal Finishing Job Shops
Non-Chromium Anodizer
Printed Wiring Board
Steel Forming and Finishing
Oily Wastes
Railroad Line Maintenance
Shiubuilding Dry Dock
Total No. of
Regulated
Sites
3,795
16
NA(e)
12
43
912
NA(4)
NA(4)
Baseline Pollutant Loadings
Ib-eq/yr
21,859,748
5,598,845
-
2,727,103
400,524
257,894
-
-
Ibs/yr (d)
508,792,176
23,147,897
-
29,122,704
3,713,703
12,942,097
-
-
Pollutant Removals by Selected Option (c)
Ib-eq/yr
5,513,689
1,626,502
-
920,640
115,624
36,866
-
-
Ibs/yr (d)
75,222,259
4,595,928
-
5,128,256
731,264
1,471,328
-
-
% Reduction from
Baseline (Ib-eq/yr)
25.2%
29.1%
-
33.8%
28.9%
14.3%
-
-
to
Source: MP&M pollutant loadings.
(a) Pollutant loadings and removal estimates presented in this table will not equate with those presented in the Cost-Effectiveness Analysis and the EEBA. The
estimates in those documents do not include pollutant loadings from facilities that are projected to close in the baseline.
(b) See Tables 12-13 through 12-20 for pollutant-specific removals for each Subcategory.
(c) These removals account for removals by publicly owned treatment works for each pollutant for the Selected Option.
(d) Does not include sodium, calcium, total dissolved solids, chemical oxygen demand and potassium.
(e) EPA is not proposing pretreatment standards for these subcategories.
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-6
Top Pollutants Removed by Proposed Option for
General Metals Direct Dischargers
Pollutant Name
TOTAL SULFIDE
TIN
COPPER
CYANIDE
SILVER
BORON
LEAD
MOLYBDENUM
ALUMINUM
ZINC
ANTHRACENE
NICKEL
CHROMIUM
CADMIUM
HEXAVALENT CHROMIUM
MANGANESE
ANILINE
[RON
FLUORANTHENE
FLUORIDE
FLUORENE
BIS(2-ETHYLHEXYL) PHTHALATE
ACROLEIN
N-NITROSODIMETHYLAMINE
PHENANTHRENE
3 ,6-DIMETHYLPHENANTHRENE
CARBON DISULFIDE
DI-N-OCTYL PHTHALATE
DIBENZOFURAN
Toxic Pound Equivalents
Removed (Ib-eq/yr)
421,356
251,019
242,366
202,008
119,080
82,034
62,838
25,118
19,104
15,234
14,466
14,075
10,602
10,317
8,309
7,814
7,640
5,338
4,643
4,496
4,051
3,080
3,076
1,771
1,703
1,596
1,482
1,272
1,091
Pounds Removed (Ib/yr)
150,484
836,729
384,707
183,644
7,442
455,746
28,563
125,590
298,496
324,130
5,786
127,953
139,495
3,968
16,293
111,630
5,457
953,206
5,804
128,464
5,787
32,421
3,171
25,302
5,873
5,910
529
5,781
5,455
12-17
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-6 (Continued)
Pollutant Name
BENZOIC ACID
SELENIUM
AMMONIA AS NITROGEN
2,6-DINITROTOLUENE
PYRENE
N-TETRADECANE
1 -METHYLPHENANTHRENE
ARSENIC
Toxic Pound Equivalents
Removed (Ib-eq/yr)
997
910
817
645
637
619
610
543
Pounds Removed (Ib/yr)
3,019,908
827
326,833
6,449
5,786
143,925
6,102
155
Source: MP&M pollutant loadings.
12-18
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-7
Top Pollutants Removed by Proposed Option for Metal Finishing
Job Shops Direct Dischargers
Pollutant Name
CYANIDE
TIN
COPPER
TOTAL SULFIDE
NICKEL
BORON
CHROMIUM
LEAD
ANTHRACENE
ZINC
ANILINE
HEXAVALENT CHROMIUM
FLUORANTHENE
FLUORENE
ACROLEIN
SILVER
MOLYBDENUM
ALUMINUM
PHENANTHRENE
3 ,6-DIMETHYLPHENANTHRENE
[RON
DI-N-OCTYL PHTHALATE
DIBENZOFURAN
MANGANESE
CADMIUM
FLUORIDE
BIS(2-ETHYLHEXYL) PHTHALATE
N-NITROSODIMETHYLAMINE
PYRENE
AMMONIA AS NITROGEN
Toxic Pound Equivalents
Removed (Ib-eq/yr)
6,257
3,508
2,496
2,133
585
356
246
179
157
94
88
77
50
44
39
37
35
30
18
17
17
14
13
11
9
8
7
7
7
7
Pounds Removed (Ib/yr)
5,688
11,694
3,962
762
5,316
1,976
3,239
81
63
2,008
63
150
63
63
40
2
174
475
63
64
3,038
63
63
154
4
215
74
100
63
2,756
12-19
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-7 (Continued)
Pollutant Name
2,6-DINITROTOLUENE
1 -METHYLPHENANTHRENE
2-METHYLNAPHTHALENE
2-ISOPROPYLNAPHTHALENE
N-NITROSODIPHENYLAMINE
1-METHYLFLUORENE
DIBENZOTHIOPHENE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
6
6
5
5
4
3
3
Pounds Removed (Ib/yr)
65
65
61
66
102
62
63
Source: MP&M pollutant loadings.
12-20
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-8
Top Pollutants Removed by Proposed Option for Printed
Wiring Board Direct Dischargers
Pollutant Name
TIN
TOTAL SULFIDE
COPPER
CARBON DISULFIDE
NICKEL
CYANIDE
LEAD
BORON
ZINC
ALUMINUM
[RON
MOLYBDENUM
CHROMIUM
MANGANESE
SILVER
ACROLEIN
ANTHRACENE
AMMONIA AS NITROGEN
FLUORIDE
ARSENIC
ANILINE
FLUORANTHENE
FLUORENE
TITANIUM
COBALT
N-NITROSODIMETHYLAMINE
BENZOIC ACID
PHENANTHRENE
BIS(2-ETHYLHEXYL) PHTHALATE
3 ,6-DIMETHYLPHENANTHRENE
DI-N-OCTYL PHTHALATE
DIBENZOFURAN
1, 1-DICHLOROETHENE
SULFATE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
23,886
16,121
14,562
3,311
2,155
1,487
1,013
623
263
208
176
155
146
76
57
56
43
43
30
26
24
14
12
10
7
6
6
5
5
5
4
3
3
3
Pounds Removed (Ib/yr)
79,619
5,757
23,114
1,183
19,593
1,351
460
3,460
5,594
3,244
31,420
774
1,926
1,083
4
57
17
17,090
870
7
17
17
17
335
59
88
17,689
17
50
17
17
17
16
474.868
Source: MP&M pollutant loadings.
12-21
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-9
Top Pollutants Removed by Proposed Option for Steel Forming
and Finishing Direct Dischargers
Pollutant Name
TOTAL SULFIDE
TIN
COPPER
BORON
LEAD
NICKEL
SILVER
ALUMINUM
CYANIDE
CHROMIUM
FLUORIDE
ACROLEIN
ANTHRACENE
ZINC
CARBON DISULFIDE
ANILINE
MOLYBDENUM
MANGANESE
FLUORANTHENE
ARSENIC
FLUORENE
VANADIUM
SELENIUM
AMMONIA AS NITROGEN
[RON
CHLORIDE
N-NITROSODIMETHYLAMINE
3 ,6-DIMETHYLPHENANTHRENE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
252,728
29,991
23,848
11,125
4,515
2,365
2,209
1,899
1,228
1,117
924
911
864
843
575
438
298
293
273
250
239
214
172
160
132
119
111
107
Pounds Removed (Ib/yr)
90,260
99,970
37,854
61,804
2,052
21,501
138
29,672
1,116
14,701
26,392
939
346
17,935
205
313
1,490
4,193
342
71
342
346
156
64,119
23,646
4,939,545
1,588
398
12-22
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-9 (Continued)
Pollutant Name
MERCURY
PHENANTHRENE
BIS(2-ETHYLHEXYL) PHTHALATE
DI-N-OCTYL PHTHALATE
DIBENZOFURAN
MAGNESIUM
HEXAVALENT CHROMIUM
2,6-DINITROTOLUENE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
103
103
94
75
63
59
51
50
Pounds Removed (Ib/yr)
1
353
984
341
313
67,510
100
500
Source: MP&M pollutant loadings.
12-23
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-10
Top Pollutants Removed by Proposed Option for
Oily Wastes Direct Dischargers
Pollutant Name
TOTAL SULFIDE
LEAD
BORON
COPPER
MOLYBDENUM
SILVER
CADMIUM
ANTHRACENE
ALUMINUM
ANILINE
FLUORANTHENE
[RON
FLUORENE
ZINC
PHENANTHRENE
ACROLEIN
3 ,6-DIMETHYLPHENANTHRENE
DI-N-OCTYL PHTHALATE
N-NITROSODIMETHYLAMINE
DIBENZOFURAN
NICKEL
BENZOIC ACID
BIS(2-ETHYLHEXYL) PHTHALATE
2,6-DINITROTOLUENE
PYRENE
TIN
ARSENIC
2-ISOPROPYLNAPHTHALENE
MAGNESIUM
FLUORIDE
N-NITROSODIPHENYLAMINE
2-METHYLNAPHTHALENE
CHROMIUM
1 -METHYLPHENANTHRENE
MANGANESE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
6,141
1,973
1,556
1,160
865
823
709
646
312
288
207
196
181
170
77
64
63
63
56
41
36
36
35
29
28
21
20
20
18
17
17
16
16
13
12
Pounds Removed (Ib/yr)
2,193
897
8,643
1,842
4,325
51
273
258
4,870
206
259
34,979
258
3,607
266
66
235
285
800
206
325
108,125
372
289
258
71
6
271
20,363
487
421
202
207
127
170
Source: MP&M pollutant loadings.
12-24
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-11
Top Pollutants Removed by Proposed Option for Railroad
Line Maintenance Direct Dischargers
Pollutant Name
BORON
LEAD
TOTAL SULFIDE
ALUMINUM
SILVER
TIN
CADMIUM
COPPER
[RON
ZINC
MANGANESE
ANTHRACENE
ANILINE
MOLYBDENUM
CHROMIUM
NICKEL
FLUORANTHENE
N-NITROSODIMETHYLAMINE
FLUORENE
TITANIUM
3 ,6-DIMETHYLPHENANTHRENE
2-METHYLNAPHTHALENE
DIBENZOFURAN
PHENANTHRENE
1 -METHYLPHENANTHRENE
BIS(2-ETHYLHEXYL) PHTHALATE
VANADIUM
2-ISOPROPYLNAPHTHALENE
N-NITROSODIPHENYLAMINE
DI-N-OCTYL PHTHALATE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
87
24
21
9.036
7.803
5.876
4.975
4.541
1.746
1.551
1.396
0.909
0.868
0.490
0.490
0.296
0.291
0.279
0.255
0.197
0.181
0.128
0.124
0.107
0.100
0.082
0.068
0.058
0.051
0.050
Pounds Removed (Ib/yr)
485
11
7.332
141
0.488
20
1.914
7.208
312
33
20
0.364
0.620
2.451
6.443
2.695
0.364
3.982
0.364
6.777
0.672
1.598
0.620
0.368
1.003
0.860
0.110
0.799
1.268
0.228
Source: MP&M pollutant loadings.
12-25
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-12
Top Pollutants Removed by Proposed Option for Shipbuilding Dry Dock
Direct Dischargers
Pollutant Name
CHROMIUM
MANGANESE
NICKEL
MOLYBDENUM
BENZOIC ACID
1 -METHYLPHENANTHRENE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
63
36
7.71
3.53
0.235
0.041
Pounds Removed (Ib/yr)
832
515
70
17.64
712
0.409
Source: MP&M pollutant loadings.
12-26
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-13
Top Pollutants Removed by Proposed Option for
General Metals Indirect Dischargers3
Pollutant Name
COPPER
TOTAL SULFIDE
TIN
BORON
LEAD
NICKEL
CYANIDE
MOLYBDENUM
MANGANESE
FLUORIDE
VANADIUM
ZINC
CHROMIUM
ALUMINUM
[RON
SILVER
ANTHRACENE
CADMIUM
AMMONIA AS NITROGEN
FLUORANTHENE
ARSENIC
COBALT
FLUORENE
SELENIUM
HEXAVALENT CHROMIUM
ACROLEIN
TITANIUM
BIS(2-ETHYLHEXYL) PHTHALATE
BENZOIC ACID
ANILINE
MAGNESIUM
CARBON DISULFIDE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
1,792,625
1,383,215
1,212,529
559,185
527,231
315,515
312,109
241,330
229,618
126,412
57,919
44,761
42,165
40,314
34,230
26,973
11,743
10,250
10,126
9,817
4,871
4,444
4,423
4,179
3,380
2,665
2,577
2,531
2,180
1,792
1,787
1,714
Pounds Removed (Ib/yr)
2,845,436
494,006
4,041,764
3,106,581
239,651
2,868,315
283,735
1,206,652
3,280,260
3,611,778
93,417
952,356
554,801
629,903
6,112,555
1,686
4,697
3,942
4,050,566
12,271
1,392
40,402
6,319
3,800
6,628
2,748
88,874
26,643
6,607,285
1,280
2,053,495
612
12-27
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-13 (continued)
Pollutant Name
CHLORIDE
DI-N-OCTYL PHTHALATE
N-NITROSODIMETHYLAMINE
2-METHYLNAPHTHALENE
3 ,6-DIMETHYLPHENANTHRENE
raALLIUM
DIBENZOFURAN
2.6-DINITROTOLUENE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
1,594
1,481
1,447
1,290
954
923
872
569
Pounds Removed (Ib/yr)
66,435,600
6,731
20,669
16,126
3,532
923
4,358
5.693
Source: MP&M pollutant loadings.
(a) The Proposed Option for General Metals indirect dischargers includes only those facilities that discharge greater
than 1 MGY of process wastewater.
12-28
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-14
Top Pollutants Removed by Proposed Option for Metal Finishing
Job Shops Indirect Dischargers
Pollutant Name
CYANIDE
TIN
COPPER
TOTAL SULFIDE
BORON
NICKEL
LEAD
CHROMIUM
MANGANESE
FLUORIDE
SILVER
ZINC
CADMIUM
[RON
MOLYBDENUM
CARBON DISULFIDE
3EXAVALENT CHROMIUM
ALUMINUM
AMMONIA AS NITROGEN
VANADIUM
ANTHRACENE
-LUORANTHENE
ARSENIC
ACROLEIN
THALLIUM
-LUORENE
COBALT
CHLORIDE
SELENIUM
3IS(2-ETHYLHEXYL) PHTHALATE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
1,113,405
242,337
148,476
122,061
44,719
25,840
11,537
7,741
7,186
5,055
4,598
4,149
3,681
2,930
2,700
2,647
1,266
1,219
964
605
440
360
277
272
185
165
164
150
92
81
Pounds Removed (Ib/yr)
1,012,187
807,789
235,676
43,593
248,436
234,910
5,244
101,853
102,654
144,432
287
88,282
1,416
523,164
13,498
945
2,483
19,053
385,723
977
176
450
79
280
185
236
1,488
6,256,880
84
851
12-29
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-14 (Continued)
Pollutant Name
TITANIUM
ANILINE
MAGNESIUM
N-NITROSODIMETHYLAMINE
2-METHYLNAPHTHALENE
DI-N-OCTYL PHTHALATE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
78
71
59
58
56
54
Pounds Removed (Ib/yr)
2,676
51
68,292
832
695
247
Source: MP&M pollutant loadings.
12-30
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-15
Top Pollutants Removed by Option 2 for Non-Chromium
Anodizing Indirect Dischargers3
Pollutant Name
NICKEL
MANGANESE
BORON
TOTAL SULFIDE
ZINC
FLUORIDE
ALUMINUM
COPPER
CADMIUM
TIN
[RON
ANTHRACENE
FLUORANTHENE
CHROMIUM
MAGNESIUM
FLUORENE
ACROLEIN
Toxic Pound Equivalents
Removed (Ib-eq/yr)
3,218
2,393
1,917
1,028
966
350
267
71
44
39
22
15
12
9
6
5
5
Pounds Removed (Ib/yr)
29,251
34,185
10,652
367
20,552
9,999
4,165
112
17
129
3,868
6
15
122
6,833
8
5
Source: MP&M pollutant loadings.
(a) EPA is not proposing pretreatment standards for all indirect discharging facilities in the Non-Chromium
Anodizing subcategory. Therefore, the removals are presented only for informational purposes.
12-31
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-16
Top Pollutants Removed by Proposed Option for Printed
Wiring Board Indirect Dischargers
Pollutant Name
TIN
TOTAL SULFIDE
CYANIDE
COPPER
NICKEL
LEAD
BORON
MANGANESE
CHROMIUM
ZINC
[RON
FLUORIDE
CARBON DISULFIDE
ALUMINUM
AMMONIA AS NITROGEN
SILVER
MOLYBDENUM
COBALT
ANTHRACENE
FLUORANTHENE
ACROLEIN
FLUORENE
VANADIUM
CADMIUM
SELENIUM
TITANIUM
ANILINE
CHLORIDE
N-NITROSODIMETHYLAMINE
DI-N-OCTYL PHTHALATE
HEXAVALENT CHROMIUM
BIS(2-ETHYLHEXYL) PHTHALATE
2-METHYLNAPHTHALENE
MAGNESIUM
Toxic Pound Equivalents Removed
(Ib-eq/yr)
468,973
257,025
253,216
104,235
39,774
23,781
14,805
4,067
2,374
2,090
,732
,568
,510
,164
,065
740
701
247
245
200
112
92
69
66
63
48
40
36
34
30
26
24
23
21
Pounds Removed (Ib/yr)
1,563,245
91,795
230,197
165,453
361,578
10,810
82,250
58,107
31,243
44,460
309,307
44,797
539
18,187
425,901
46
3,507
2,247
98
250
116
131
111
25
57
1,664
28
1,515,053
489
137
52
252
286
24.041
Source: MP&M pollutant loadings.
12-32
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-17
Top Pollutants Removed by Proposed Option for Steel Forming
and Finishing Indirect Dischargers
Pollutant Name
TIN
TOTAL SULFIDE
COPPER
BORON
FLUORIDE
[RON
NICKEL
ZINC
AMMONIA AS NITROGEN
VANADIUM
CHROMIUM
ANTHRACENE
LEAD
MANGANESE
FLUORANTHENE
CYANIDE
CHLORIDE
MOLYBDENUM
FLUORENE
ALUMINUM
TITANIUM
DI-N-OCTYL PHTHALATE
ANILINE
ACROLEIN
SELENIUM
SILVER
ARSENIC
COBALT
BIS(2-ETHYLHEXYL) PHTHALATE
2-METHYLNAPHTHALENE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
68,545
53,018
37,074
4,355
3,093
1,425
1,229
522
359
295
290
270
257
250
221
199
160
118
101
72
42
33
28
28
26
25
22
21
19
17
Pounds Removed (Ib/yr)
228,482
18,935
58,848
24,193
88,365
254,463
11,174
11,104
143,769
476
3,812
108
117
3,565
276
181
6,684,396
591
145
1,122
1,436
152
20
29
24
2
6
187
202
216
12-33
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-17 (Continued)
Pollutant Name
CADMIUM
MAGNESIUM
DIBENZOFURAN
3 ,6-DIMETHYLPHENANTHRENE
2,6-DINITROTOLUENE
N-NITROSODIMETHYLAMINE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
16
15
14
13
11
11
Pounds Removed (Ib/yr)
6
16,829
69
48
111
158
Source: MP&M pollutant loadings.
12-34
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-18
Top Pollutants Removed by Proposed Option for
Oily Wastes Indirect Dischargers3
Pollutant Name
TOTAL SULFIDE
MOLYBDENUM
BENZOIC ACID
LEAD
COPPER
ANTHRACENE
FLUORANTHENE
CADMIUM
SELENIUM
FLUORENE
ARSENIC
ZINC
NICKEL
[RON
BIS(2-ETHYLHEXYL) PHTHALATE
DI-N-OCTYL PHTHALATE
2-METHYLNAPHTHALENE
ANILINE
ACROLEIN
ALUMINUM
MAGNESIUM
3 ,6-DIMETHYLPHENANTHRENE
DIBENZOFURAN
CHROMIUM
N-NITROSODIMETHYLAMINE
2,6-DINITROTOLUENE
N-TETRADECANE
PYRENE
2-ISOPROPYLNAPHTHALENE
PHENANTHRENE
1 -METHYLPHENANTHRENE
MANGANESE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
40,158
35,485
366
166
137
117
96
93
89
44
34
33
26
25
20
14
14
14
10
8
7
7
7
6
6
5
5
4
3
3
o
J
2
Pounds Removed (Ib/yr)
14,342
177,425
1,108,465
75
217
47
120
36
81
63
10
710
236
4,411
216
66
178
10
11
119
7,949
26
33
82
86
54
1,204
34
47
11
27
30
Source: MP&M pollutant loadings.
(a) The Proposed Option for Oily Wastes indirect dischargers includes only those facilities that discharge greater
than 2 MGY of process wastewater. The pollutant removals on this table reflect those associated with the Selected
Option.
12-35
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-19
Top Pollutants Removed by Option 10 for Railroad
Line Maintenance Indirect Dischargers
Pollutant Name
LEAD
MANGANESE
ANTHRACENE
FLUORANTHENE
TIN
COPPER
BORON
FLUORENE
FLUORIDE
CADMIUM
SILVER
SELENIUM
DI-N-OCTYL PHTHALATE
ALUMINUM
MERCURY
ANILINE
ZINC
MOLYBDENUM
VANADIUM
2-METHYLNAPHTHALENE
CARBON DISULFIDE
NICKEL
[RON
BIS(2-ETHYLHEXYL) PHTHALATE
ARSENIC
HEXAVALENT CHROMIUM
DIBENZOFURAN
3 ,6-DIMETHYLPHENANTHRENE
COBALT
2,6-DINITROTOLUENE
N-NITROSODIMETHYLAMINE
PYRENE
ACROLEIN
PHENANTHRENE
Toxic Pound Equivalents
Removed (Ib-eq/yr)
2.67
2.13
2.13
1.74
1.39
1.00
0.801
0.798
0.527
0.427
0.299
0.274
0.221
0.216
0.214
0.208
0.192
0.190
0.184
0.147
0.140
0.124
0.120
0.115
0.114
0.106
0.102
0.094
0.086
0.085
0.073
0.067
0.066
0.056
Pounds Removed (Ib/yr)
1.21
30.4
0.85
2.18
4.62
1.59
4.45
1.14
15.1
0.164
0.019
0.249
1.00
3.38
0.002
0.149
4.09
0.950
0.296
1.84
0.050
1.13
21.4
1.21
0.032
0.208
0.512
0.346
0.780
0.850
1.05
0.609
0.068
0.193
Source: MP&M pollutant loadings.
12-36
-------
12.0 - Pollutant Loading and Reduction Estimates
Table 12-20
Top Pollutants Removed by Option 10 for Shipbuilding
Dry Dock Indirect Dischargers
Pollutant Name
BORON
MOLYBDENUM
MANGANESE
Toxic Pound Equivalents Removed
(Ib-eq/yr)
26.1
0.062
0.030
Pounds Removed (Ib/yr)
145
0.309
0.426
Source: MP&M pollutant loadings.
12-37
-------
13.0 Non-Water Quality Impacts
is.o NON-WATER QUALITY IMPACTS
Sections 304(b) and 306 of the Clean Water Act require EPA to consider non-
water quality environmental impacts (including energy requirements) associated with effluent
limitations guidelines and standards. To comply with these requirements, EPA considered the
potential impact of the proposed MP&M rule on energy consumption, air emissions, and solid
waste generation. A discussion of the proposed technology options is given in Section 14 of this
document.
Considering energy use and environmental impacts across all media, the Agency
has determined that the impacts identified in this section are justified by the benefits associated
with compliance with the proposed limitations and standards.
Section 13.1 discusses the energy requirements for implementing wastewater
treatment technologies at MP&M facilities. Section 13.2 presents the impact of the proposed
technologies on air emissions, and section 13.3 discusses the impact on wastewater treatment
sludge and waste oil generation.
13.1 Energy Requirements
EPA estimates that compliance with this rule will result in a net increase in energy
consumption at MP&M facilities. Table 13-1 presents estimates of energy usage by technology
option.
Table 13-1
Energy Usage by Option
Option
Basic Technology (Options 1,5, and 9)
Basic Technology with Water Conservation and Pollution Prevention (Options 2, 6, and 10)
Advanced Technology (Options 3 and 7)
Advanced Technology with Water Conservation and Pollution Prevention (Options 4 and 8)
Selected Option for Existing Sources'5 (Options 2, 6, and 10 with flow cutoffs)
Incremental
Energy Required3
(106 kilowatt
hrs/yr)
181
208
1,747
1,736
116
Source: MP&M Design and Cost Model output.
a The amount of additional energy required (from baseline) if the technology option is implemented, summed for all
regulated facilities.
b The Selected Option for Existing Sources regulates fewer MP&M facilities than other options shown in the table
due to flow cutoffs (see Section 14).
13-1
-------
13.0 Non-Water Quality Impacts
For the Basic Technology option, EPA found that options with pollution
prevention and water conservation practices (Options 2, 6, 10) may use slightly more additional
energy as compared to those without pollution prevention and water conservation (Options 1, 5,
9). This may be due to the number of facilities that have the Basic Technology option treatment
in place prior to the regulation (leading to a smaller incremental energy requirement) compared
to the number of facilities that have pollution prevention and water conservation in place prior to
the regulation (leading to a higher incremental energy requirement). Note that the reverse is true
for the Advanced Technology option. However, the Advanced Technology option (with or
without pollution prevention) consumes much more additional energy than the basic option.
The Advanced Technology options (3/7 and 4/8) include ultrafiltration and
microfiltration technologies which require significant amounts of energy in comparison to the
oil/water separators and clarifiers required for Basic Technology options (1/5/9 and 2/6/10). The
Selected Option for Existing Sources requires the least amount of additional energy consumption
because fewer MP&M facilities will be affected than other options shown in the table due to
proposed flow cutoffs. (See Section 14 for a discussion of flow cutoffs).
Approximately 3,123 billion kilowatt hours of electric power were generated in
the United States in 1997 (1). Additional energy requirements to implement EPA's proposed
option correspond to approximately 0.01 percent of the national requirements. The increase in
energy requirements due to the implementation of MP&M technologies will in turn cause an air
emissions impact from the electric power generation facilities providing the additional energy.
EPA expects the increase in air emissions to be minimal as it is proportional to the increase in
energy requirements, or approximately 0.01 percent.
13.2 Air Emissions Impacts
The Agency believes that the in-process and end-of-pipe technologies included in
the technology options for this rule do not generate significant air emissions.
EPA is developing National Emission Standards for Hazardous Air Pollutants
(NESHAPs) under Section 112 of the Clean Air Act (CAA) to address air emissions of the
hazardous air pollutants (HAPs) listed in Title III of the CAA Amendments of 1990 (CAAA).
Below is a list of current and upcoming NESHAPs that may potentially affect HAP-emitting
activities at MP&M sites:
• Chromium Emissions from Hard and Decorative Chromium Electroplating
and Chromium Anodizing Tanks - Proposed December 16, 1993 and
promulgated on January 25, 1995;
Halogenated Solvent Cleaning - Proposed November 29, 1993 and
promulgated on December 2, 1994;
13-2
-------
13.0 Non-Water Quality Impacts
Aerospace Manufacturing - Proposed June 6, 1994 and promulgated on
July 31, 1995;
• Shipbuilding and Ship Repair (Surface Coating);
• Large Appliances (Surface Coating);
• Metal Furniture (Surface Coating);
• Automobile and Light-Duty Truck Manufacturing (Surface Coating); and
• Miscellaneous Metal Parts and Products (Surface Coating) - scheduled for
promulgation on November 15, 2000.
These NESHAPs define the maximum achievable control technology (MACT) for
emissions of HAPS. Like effluent guidelines, MACT standards are technology-based. The
CAAA set maximum control requirements on which MACT can be based for new and existing
sources.
Halogenated HAP solvents (e.g., methylene chloride, perchloroethylene,
trichloroethylene, 1,1,1-trichloroethane, carbon tetrachloride, and chloroform) used for cleaning
in the MP&M industry can be a source of hazardous air emissions. EPA believes the proposed
MP&M rule will not affect the use of solvents containing halogenated hazardous air pollutants in
the MP&M industry. This rule neither requires nor discourages the use of aqueous cleaners in
lieu of halogenated hazardous air pollutant solvents.
13.3 Solid Waste Generation
Solid waste generated at MP&M sites includes hazardous and nonhazardous
wastewater treatment sludge as well as waste oil removed in wastewater treatment. EPA
estimates that compliance with this proposed rule will result in a decrease in wastewater
treatment sludge and an increase in waste oil generated at MP&M facilities. Sections 13.3.1 and
13.3.2 discuss the impacts of the proposed rule on the generation of wastewater treatment sludge
and waste oil, respectively.
13.3.1 Wastewater Treatment Sludge
Based on EPA's detailed questionnaires (see Section 3.0), the Agency estimates
that MP&M facilities generated 267 million gallons of wastewater treatment sludge in 1996.
EPA estimates that implementing the proposed wastewater treatment technology options (which
incorporate water conservation and pollution prevention practices) will reduce sludge generation.
Table 13-2 presents the amount of wastewater treatment sludge expected to be reduced as a result
of implementing each of the technology options.
13-3
-------
13.0 Non-Water Quality Impacts
Table 13-2
Wastewater Treatment Sludge by Option
Option
Basic Technology (Options 1, 5, and 9)
Basic Technology with Water Conservation and Pollution Prevention (Options 2, 6, and 10)
Advanced Technology (Options 3 and 7)
Advanced Technology with Water Conservation and Pollution Prevention (Options 4 and 8)
Selected Option for Existing Sourcesb (Options 2, 6, and 10 with flow cutoffs)
Reduction in
Sludge
Generated3
(million
gal/yr)
62.9
63.6
62.8
62.9
61.1
Source: MP&M Design and Cost Model output
deduction in the amount of sludge generated (from baseline) if the technology option is implemented, summed for
all regulated facilities.
bThe Selected Option for Existing Sources regulates fewer MP&M facilities than other options shown in the table
due to flow cutoffs (see Section 14).
As shown in Table 13-2, wastewater treatment sludge generation decreases with
implementation of the wastewater treatment technology options. These options include sludge
dewatering, which decreases sludge generation at sites that have chemical precipitation and
settling technologies without sludge dewatering in place at baseline. EPA did not estimate
sludge reduction at sites that already practice sludge dewatering.
The water conservation and pollution prevention technologies result in a greater
sludge reduction. EPA expects these technologies to reduce sludge generation for the following
reasons:
• Water conservation technologies reduce the amount of source water used
and thus mass of metals in the source water entering the unit processes at a
site (e.g., calcium, sodium), which reduces the amount of sludge generated
during metals removal.
Recycling of coolants and paint curtain wastewater reduces the mass of
metal pollutants in treatment system influent streams, which reduces the
amount of sludge generated during metals removal.
Bath maintenance practices, including good operational practices
regarding drag-out in plating processes, reduce the mass of metal
pollutants in treatment system influent streams, which in turn reduces the
amount of sludge generated during metals removal.
13-4
-------
13.0 Non-Water Quality Impacts
EPA classifies many sludges generated at MP&M facilities as either listed or
characteristic hazardous wastes under the Resource Conservation and Recovery Act (RCRA) as
follows:
EPA classifies the sludge resulting from electroplating operations as EPA
hazardous waste code F006 (40 CFR 261.31). If the facility mixes the
wastewater from these electroplating operations with other
nonelectroplating wastewater for treatment, EPA still considers all of the
sludge generated from the treatment of this commingled waste stream to
be a listed hazardous waste F006; or
• If the sludge or waste oil from wastewater treatment exceeds the standards
for the Toxicity Characteristic (i.e, is hazardous), or exhibits other RCRA-
defmed hazardous characteristics (e.g., reactive, corrosive, or flammable),
EPA considers it a characteristic hazardous waste (40 CFR 261.24).
EPA does not include chemical conversion coating, electroless plating, and
printed circuit board manufacturing under the F006 listing (51 FR 43351, December 2, 1986). If
the facility performs certain chemical conversion coating operations on aluminum, EPA
classifies the resulting sludge as EPA hazardous waste number F019.
State and local regulations may also define MP&M sludges as hazardous wastes.
Facilities should check with the applicable authorized authority to determine if other regulations
apply.
Based on information collected during site visits and sampling episodes, the
Agency believes that some of the solid waste generated at MP&M facilities would not be
classified as hazardous. However, for the purpose of compliance cost estimation, the Agency
assumed that all solid waste generated as a result of implementing the proposed technology
options would be hazardous.
13.3.2 Waste Oil
Based on the Agency's detailed questionnaire, EPA estimates that MP&M
facilities generated 805 million gallons of waste oil in 1996. Table 13-3 presents the amount of
additional waste oil expected to be removed as a result of implementing each of the technology
options.
13-5
-------
13.0 Non-Water Quality Impacts
Table 13-3
Waste Oil Removed by Option
Option
Basic Technology (Options 1, 5, and 9)
Basic Technology with Water Conservation and Pollution Prevention (Options 2, 6, and 10)
Advanced Technology (Options 3 and 7)
Advanced Technology with Water Conservation and Pollution Prevention (Options 4 and 8)
Selected Option for Existing Sources'5 (Options 2, 6, and 10 with flow cutoffs)
Incremental
Waste Oil
Removed3
(million gal/yr)
1,350
944
597
585
841
Source: MP&M Design and Cost Model output.
aThe amount of additional oil removed (from baseline) if the technology option is implemented, summed for all
regulated facilities.
bThe Selected Option for Existing Sources regulates fewer MP&M facilities than other options shown in the table
due to flow cutoffs (see Section 14).
The removal of oil from MP&M wastewater prior to discharge to POTWs or
surface waters results in an increase in waste oil generation from baseline to the proposed
options. MP&M facilities usually either recycle waste oil on or off site, or contract haul it for
disposal as either a hazardous or nonhazardous waste. The increase in waste oil generation
reflects better removal of oil from the wastewater, and does not reflect an increase in overall oil
use at MP&M facilities. For the purpose of compliance cost estimation, EPA assumed that all
waste oil was contract hauled for disposal; however, EPA expects that some of the waste oil can
be recycled either on or off site.
The decrease in waste oil removed from Options (1/5/9) to Options (2/6/10) is due
to the 80 percent reduction of coolant discharge using the recycling technology included in the
Options (2/6/10) technology trains. This system recovers and recycles oil-bearing machining
coolants at the source, reducing the generation of spent coolant and extending the useful life of
the coolant. The decrease in waste oil removed from Options (2/6/10) to the Selected Option for
Existing Sources is due to the decrease in the number of regulated MP&M facilities as a result of
the proposed flow cutoffs. (See Section 14 for discussion of flow cutoffs).
13.4 References
1. The Energy Information Administration. Electric Power Annual 1998 Volume 1.
Table Al, 1998.
13-6
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14.0 - Effluent Limitations and Standards
14.0 EFFLUENT LIMITATIONS AND STANDARDS
This section presents the proposed MP&M effluent limitations guidelines and
standards for each regulatory level of control required by the Clean Water Act (CWA) and
discusses the technology options. Section 1.0 discusses these levels of control. The proposed
limitations and standards are based on the technologies included in Options 2, 4, 6 and 10, as
discussed in Section 9.0. Except for the Steel Forming and Finishing Subcategory, the proposed
MP&M effluent limitations guidelines and standards consist of concentration-based limitations
for all new and existing direct and indirect dischargers within the scope of the proposed rule.
The proposed MP&M effluent limitations guidelines and standards for the Steel Forming and
Finishing Subcategory consist of mass-based limitations for all new and existing direct and
indirect dischargers. In this Section, EPA provides its rationale for proposing different levels for
the low flow exclusion for indirect dischargers in various subcategories. Direct dischargers are
sites that discharge wastewater to a surface water. Indirect dischargers are sites that discharge
wastewater to a publicly owned treatment works (POTW).
Sections 14.1 through 14. 7 discuss EPA's rationale for selecting the proposed
option and summarizes the effluent limitations and standards for each of the regulatory levels of
control for each Subcategory. The Statistical Support Document for the Proposed Effluent
Limitations Guidelines and Standards for the Metal Products & Machinery Industry [EPA-821-
B-00-006] contains detailed information on those facilities EPA used in calculating the proposed
BPT limitations and establishes the statistical methodology for developing numerical discharge
limitations. Section 10.0 of this document summarizes EPA's methodology for calculating
effluent limits, Section 9.0 discusses in detail all of the MP&M technology options, and Sections
11.0 and 12.0 discuss costs and loads, respectively.
14.1 Best Practicable Control Technology Currently Available (BPT)
EPA defines BPT effluent limits for conventional, toxic (priority), and non-
conventional pollutants for direct discharging facilities. In specifying BPT, EPA looks at a
number of factors. EPA first considers the cost of achieving effluent reductions in relation to the
effluent reduction benefits. The Agency also considers the age of the equipment and facilities,
the processes employed and any required process changes, engineering aspects of the control
technologies, non-water quality environmental impacts (including energy requirements), and
such other factors as the Agency deems appropriate (CWA 304(b)(l)(B)). Traditionally, EPA
establishes BPT effluent limitations based on the average of the best performances of facilities
within the industry of various ages, sizes, processes, or other common characteristics. Where
existing performance is uniformly inadequate, EPA may require higher levels of control than are
currently in place in an industrial category if the Agency determines that the technology can be
practically applied. See "A Legislative History of the Federal Water Pollution Control Act
Amendments of 1972," U.S. Senate Committee of Public Works, Serial No. 93-1, January 1973,
p. 1468.
14-1
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14.0 - Effluent Limitations and Standards
In addition, CWA Section 304(b)(l)(B) requires a cost-reasonableness assessment
for BPT limitations. In determining the BPT limits, EPA must consider the total cost of
treatment technologies in relation to the effluent reduction benefits achieved. This inquiry does
not limit EPA's broad discretion to adopt BPT limitations that are achievable with available
technology unless the required additional reductions are "wholly out of proportion to the costs of
achieving such marginal level of reduction." See Legislative History, op. cit. p. 170. Moreover,
the inquiry does not require the Agency to quantify benefits in monetary terms. See, for
example, American Iron and Steel Institute v. EPA, 526 F. 2d 1027 (3rd Cir., 1975). For the
BPT cost-reasonableness assessment, EPA used the total pounds of chemical oxygen demand
(COD) removed for the General Metals, Metal Finishing Job Shops, Non-Chromium Anodizing,
Steel Forming and Finishing, Oily Wastes, and Railroad Line Maintenance subcategories because
this parameter best represented the pollutant removals without counting removals of individual
pollutants more than once. EPA used oil and grease for the cost-reasonableness assessment for
the Shipbuilding Dry Dock Subcategory because it best represented the pollutant removals for
this subcategory without counting removals of individual pollutants more than once.
In balancing costs against the benefits of effluent reduction, EPA considers the
volume and nature of expected discharges after application of BPT, the general environmental
effects of pollutants, and the cost and economic impacts of the required level of pollution control.
In past effluent limitations guidelines and standards, BPT cost-reasonableness has ranged from
$0.94/lb removed to $34.34/lb removed in 1996 dollars. In developing guidelines, the CWA
does not require or permit consideration of water quality problems attributable to particular point
sources, or water quality improvements in particular bodies of water. Therefore, EPA did not
consider these factors in developing the proposed MP&M limitations. See Weyerhaeuser
Company v. Costle, 590 F. 2d 1011 (D.C. Cir. 1978).
Table 14-1 summarizes the pounds of pollutants removed for direct dischargers,
and Table 14-2 summarizes the costs, costs per pound removed, and economic impacts for direct
dischargers associated with each of the proposed options by subcategory. (See Section 14.4 for
summary tables for indirect dischargers.)
EPA notes that the pounds removed presented in Table 14-1 may differ from the
pounds removed presented in the Economic. Environmental, and Benefits Analysis of the
Proposed Metal Products & Machinery Rule [EPA-821-B-00-0058]. This document presents the
methodology employed to assess economic and environmental impacts of the proposed rule and
the results of the analysis. The difference in pounds removed occurs because the Agency does
not include facilities (or the associated pollutant loadings and removals) that closed at the
baseline (i.e., EPA predicted that these facilities would close prior to the implementation of the
MP&M rule) when performing certain economic analyses (e.g., cost-effectiveness). Table 14-1
estimates the annual pounds removed by the selected option for all of the direct discharging
facilities in EPA's questionnaire database that discharged wastewater at the time EPA collected
the data.
14-2
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14.0 - Effluent Limitations and Standards
Table 14-1
Pounds of Pollutants Removed by the Proposed BPT Option for Direct Dischargers by Subcategory
Subcategory a
(Number of Facilities)
General Metals (3 ,794)
Metal Finishing Job Shops (15)b
Printed Wiring Boards (1 l)b
Steel Forming and Finishing (43)
Oily Wastes (9 11)
Railroad Line Maintenance (34)
Shipbuilding Dry Dock (6)
Selected
Option
Option 2
Option 2
Option 2
Option 2
Option 6
Option
10
Option
10
Total
Suspended
Solids
(Ibs
removed/yr)
10.1 million
13,000
51,000
884,000
349,000
9,000
650
Oil and
Grease
(Ibs
removed/yr)
7.8 million
14,400
238,000
101,000
885,000
47,400
8.5 million
Chemical
Oxygen
Demand
(Ibs
removed/yr)
181 million
232,000
1.3 million
4.5 million
5.1 million
59,000
0
Priority and
Nonconventional
Metals
(Ibs removed/yr)
4 million
34,000
172,000
387,000
81,000
1,000
1,400
Priority and
Nonconventional
Organics
(Ibs removed/yr)
5 million
4,600
22,000
76,000
127,000
78
700
Cyanide
(Ibs
removed/yr)
184,000
5,700
1,400
1,100
10
0
0
a EPA did not identify any direct discharging facilities in the Non-Chromium Anodizing Subcategory; therefore, there are no estimated removals. See Section
14.1.3.
bAlthough EPA is not revising limits for TSS and O&G for these two subcategories, removals are reported based on incidental removals for the proposed
MP&M Option 2 technology for BPT control of toxic and nonconventional pollutants.
-------
14.0 - Effluent Limitations and Standards
Table 14-2
Annualized Costs and Economic Impacts of the Proposed BPT Option for
Direct Dischargers by Subcategory
Subcategory a
(Number of
Facilities)
General Metals
(3,794)
Metal Finishing
Job Shops (15)
Printed Wiring
Boards (11)
Steel Forming
and Finishing
(43)
Oily Wastes
(911)
Railroad Line
Maintenance
(34)
Shipbuilding
Dry Dock (6)
Selected
Option
Option 2
Option 2
Option 2
Option 2
Option 6
Option
10
Option
10
Annualized Compliance
Costs for Selected Option
($1996)
230 million
1.3 million
2.5 million
29.3 million
11. 2 million
1.18 million
2.15 million
Economic Impacts
(Facility Closures) of
Selected Option
(Percentage of
Regulated
Subcategory)
20 (<1%)
0
0
0
0
0
0
BPT Cost per
Pound Removed b
(1996 $/pound
removed)
1.22
5.60
1.92
6.51
2.18
20.00
0.25
a EPA did not identify any direct discharging facilities in the Non-Chromium Anodizing Subcategory; therefore,
there are no estimated costs. See Section 14.1.3 for estimates based on a model facility.
b EPA based the pounds used in calculating the BPT cost reasonableness on the COD removals only (shown in
Table 14-1) for each Subcategory, except for the use of oil and grease removals only (shown in Table 14-1) for the
Shipbuilding Dry Dock Subcategory.
14-4
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14.0 - Effluent Limitations and Standards
14.1.1 BPT Technology Selection for General Metals Subcategory
Section 6.2.1 describes the General Metals Subcategory. The Agency estimates
that there are approximately 3,800 direct discharging facilities in the General Metals
Subcategory. EPA estimates that the direct discharging facilities in the General Metals
Subcategory currently discharge substantial quantities of pollutants into the surface waters of the
United States, including 8.2 million pounds per year of oil and grease, 10.9 million pounds per
year of total suspended solids (TSS), 187 million pounds of COD, 5.2 million pounds per year of
priority and nonconventional metal pollutants, 5.2 million pounds of priority and
nonconventional organic pollutants, and 187,000 pounds per year of cyanide. As a result of the
quantity of pollutants currently discharged directly to the nation's waters by General Metals
facilities, EPA determined that there was a need for BPT regulation for this Subcategory.
Facilities in the General Metals Subcategory generally perform unit operations
such as cleaning, etching, electroplating, electroless plating, and conversion coating that produce
metal-bearing wastewater. In addition, some of these facilities also perform machining and
grinding, impact deformation, and surface preparation operations that generate oily wastewater.
Therefore, EPA considered technology options 1 through 4 for this Subcategory because
technologies included in these options treat both oily wastewater and metal-bearing wastewater.
As explained above, EPA only discusses options 2 and 4 in detail in this section since these
options costed less and removed more pollutants than options 1 and 3, respectively. See Section
9.0 for a discussion of technology options.
The Agency selected Option 2 as the basis for BPT regulation for the General
Metals Subcategory. EPA's decision to base BPT limitations on Option 2 treatment reflects
primarily two factors: (1) the degree of effluent reductions attainable, and (2) the total cost of the
proposed treatment technologies in relation to the effluent reductions achieved. EPA found no
basis for identifying different BPT limitations based on age, size, process, or other engineering
factors. Neither the age nor the size of a facility in the General Metals Subcategory will directly
affect the treatability of MP&M process wastewater. For facilities in this Subcategory, the most
pertinent factors for establishing the limitations are costs of treatment and the level of effluent
reductions obtainable.
Tables 14-1 and 14-2 present the annual pollutant removals for direct dischargers
for Option 2 and the cost per pound removed using only the pounds of COD removed,
respectively. EPA estimates that implementation of Option 2 will cost $1.22 per pound of COD
removed (1996 dollars). The Agency has concluded that the costs of BPT Option 2 are
achievable and are reasonable as compared to the removals achieved by this option.
The technology proposed in Option 2 represents the average of the best
performing facilities due to the prevalence of chemical precipitation followed by sedimentation
in this Subcategory. Approximately 22 percent of the direct discharging facilities in the General
Metals Subcategory employ chemical precipitation followed by a clarifier (Option 2), while less
than 1 percent employ microfiltration after chemical precipitation (Option 4).
14-5
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14.0 - Effluent Limitations and Standards
Based on the available database, Option 4 only removes, on an annual basis, an
additional 66,000 pounds of TSS, 12,300 pounds of oil and grease, 15,000 pounds of priority
metals, and 880,000 pounds of nonconventional metals, while removing 324,000 pounds less
COD and 31,000 pounds less priority and nonconventional organic pollutants than Option 2.
Although there is a large amount of additional removals of TSS and nonconventional metals for
Option 4 when considered across the entire population (3,800 facilities), the Agency determined
that these additional removals were not significant when considered on a per-facility basis. In
addition, Option 4's annualized cost is $52 million more than Option 2. EPA concluded that the
lack of significant additional pollutant removals per facility achieved by Option 4 (and the fact
that it removes less COD and organic pollutants) support the selection of Option 2 as the BPT
technology basis. Table 14-3 lists the proposed BPT limitations for existing point sources in the
General Metal Subcategory. EPA's data editing procedures and statistical methodology for
calculating BPT limitations are explained in Section 10.0.
Existing direct discharging facilities in the General Metals Subcategory must
achieve the following effluent limitations representing the application of BPT. Discharges must
remain within the pH range 6 to 9 and must not exceed the following.
14-6
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14.0 - Effluent Limitations and Standards
Table 14-3
BPT/BAT Effluent Limitations for the General Metals Subcategory
Regulated Parameter
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
Total Suspended Solids (TSS)
Oil and Grease (as HEM)
Total Organic Carbon (TOC) (as indicator)
Total Organics Parameter (TOP)
Cadmium
Chromium
Copper
Total Cyanide
Amenable Cyanide
Lead
Manganese
Molybdenum
Nickel
Silver
Sulfide, Total
Tin
Zinc
Maximum
Daily (mg/L (ppm))
34
15
87
9.0
0.14
0.25
0.55
0.21
0.14
0.04
0.13
0.79
0.50
0.22
31
1.4
0.38
Maximum
Monthly Avg.
(mg/L (ppm))
18
12
50
4.3
0.09
0.14
0.28
0.13
0.07
0.03
0.09
0.49
0.31
0.09
13
0.67
0.22
As explained in Section 15.2.7, upon agreement with the permitting authority,
facilities with cyanide treatment have the option of achieving the limitation for either total or
amenable cyanide. Additionally, upon agreement with the permitting authority, facilities must
choose to monitor for TOP or TOC, or implement a management plan for organic chemicals as
specified in Section 15.2.7.
14.1.2
BPT Technology Selection for Metal Finishing Job Shops Subcategory
Section 6.2.2 describes the Metal Finishing Job Shops Subcategory. The Agency
estimates that there are approximately 15 direct discharging facilities in the Metal Finishing Job
Shops Subcategory. EPA previously promulgated BPT and best available technology
economically achievable (BAT) limitations for all of the facilities in this Subcategory at 40 CFR
Part 413 (Electroplating Pretreatment Standards) and at 40 CFR Part 433 (Metal Finishing
Effluent Limitations Guidelines and Pretreatment Standards). However, EPA developed the
existing regulations applicable to the facilities in the Metal Finishing Job Shops Subcategory
approximately 20 years ago, and since that time, advances in electroplating and metal finishing
14-7
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14.0 - Effluent Limitations and Standards
processes, water conservation, pollution prevention, and wastewater treatment have occurred.
EPA is proposing new BPT effluent limitations guidelines for this subcategory.
EPA estimates that direct discharging facilities in the Metal Finishing Job Shops
Subcategory currently discharge substantial quantities of pollutants to the surface waters of the
United States, including 17,900 pounds per year of oil and grease, 20,500 pounds per year of
TSS, 287,400 pounds per year of COD, 44,000 pounds per year of priority and nonconventional
metal pollutants, 6,000 pounds per year of priority and nonconventional organic pollutants, and
6,000 pounds per year of cyanide. As a result of the quantity of pollutants currently discharged
directly to the nation's waters by metal finishing job shop facilities, EPA determined that there is
a need for BPT regulation for this subcategory.
Facilities in the Metal Finishing Job Shops Subcategory generally perform unit
operations such as cleaning, etching, electroplating, electroless plating, passivating, and
conversion coating that produce metal-bearing wastewater. In addition, some of these facilities
also perform machining and grinding, impact deformation, and surface preparation operations
that generate oily wastewater. Therefore, EPA considered technology options 1 through 4 for
this subcategory because technologies included in these options treat both oily wastewater as well
as metal-bearing wastewater. As explained above, EPA only discusses Options 2 and 4 in detail
in this section since these options costed less and removed more pollutants than Options 1 and 3,
respectively.
The Agency selected Option 2 as the basis for BPT regulation for the Metal
Finishing Job Shops Subcategory. The new BPT limitations incorporate more stringent effluent
requirements for priority metals, nonconventional pollutants, cyanide, and organic pollutants (by
way of an indicator parameter) as compared to the limitations contained in 40 CFR 433.13. EPA
has included the conventional pollutants, TSS and oil and grease, in the new BPT regulation for
this subcategory at the same level as 40 CFR 433.13. EPA's decision to base BPT limitations on
Option 2 treatment reflects primarily two factors: (1) the degree of effluent reductions attainable
and (2) the total cost of the proposed treatment technologies in relation to the effluent reductions
achieved. No basis could be found for identifying different BPT limitations based on age, size,
process, or other engineering factors. Neither the age nor the size of a facility in the Metal
Finishing Job Shops Subcategory will directly affect the treatability of MP&M process
wastewater. For facilities in this subcategory, the most pertinent factors for establishing the
limitations are costs of treatment and the level of effluent reductions obtainable. EPA based its
decision not to revise the conventional pollutant limitations on the use of the alternate organics
control parameters (i.e., TOC or TOP) and the small additional removals of TSS obtainable after
the incidental removal due to control of the metals.
Table 14-1 presents the annual pollutant removals for direct dischargers for
Option 2; Table 14-2 presents the cost per pound removed using only the pounds of COD
removed. EPA estimates that implementation of Option 2 will cost $5.60 per pound of COD
removed (1996 dollars). The Agency has concluded that the costs of BPT Option 2 are
achievable and are reasonable as compared to the removals achieved by this option.
14-8
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14.0 - Effluent Limitations and Standards
The technology proposed in Option 2 represents the average of the best
performing facilities due to the prevalence of chemical precipitation followed by sedimentation
in the subcategory. The Agency estimates that 100 percent of the direct discharging facilities in
the Metal Finishing Job Shops Subcategory employ chemical precipitation followed by a clarifier
(Option 2) while no facilities employ microfiltration after chemical precipitation (Option 4).
Because no facilities in this subcategory employ microfiltration after chemical precipitation for
solids separation, the Agency concluded that Option 4 does not represent the average of the best
treatment.
Based on the available data base, Option 4 only removes, on an annual basis, an
additional 6,900 pounds of priority and nonconventional metals, while removing 1,500 pounds
less COD, and 600 pounds less priority and nonconventional organic pollutants than Option 2.
EPA concluded that the lack of significant overall additional pollutant removals achieved by
Option 4 (and the fact that it removes less COD and organic pollutants) support the selection of
Option 2 as the BPT technology basis. Table 14-4 lists the proposed BPT limitations for the
Metal Finishing Job Shops Subcategory.
EPA's data editing procedures and statistical methodology for calculating BPT
limitations are explained in Section 10.0. In general, EPA calculated the new BPT limitations for
this subcategory using data from facilities in the Metal Finishing Job Shops Subcategory
employing Option 2 technology. As discussed above, EPA did not calculate new limitations for
TSS or oil and grease for this subcategory. Instead, EPA set them at the same level as in the
Metal Finishing effluent guidelines (40 CFR 433.13). For cyanide limitations, EPA used data
from all subcategories where cyanide destruction systems were sampled. If data was not
sufficient for developing BPT limitations for an individual pollutant in this subcategory, the
Agency transferred data from another subcategory.
Existing direct discharging facilities in the Metal Finishing Job Shops
Subcategory must achieve the following effluent limitations representing the application of BPT.
Discharges must remain within the pH range 6 to 9 and must not exceed the following.
14-9
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14.0 - Effluent Limitations and Standards
Table 14-4
BPT/BAT Effluent Limitations for the
Metal Finishing Job Shops Subcategory
Regulated Parameter
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
Total Suspended Solids (TSS)
Oil and Grease (as HEM)
Total Organic Carbon (TOC) (as indicator)
Total Organics Parameter (TOP)
Cadmium
Chromium
Copper
Total Cyanide
Amenable Cyanide
Lead
Manganese
Molybdenum
Nickel
Silver
Sulfide, Total
Tin
Zinc
Maximum
Daily (mg/L (ppm))
60
52
78
9.0
0.21
1.3
1.3
0.21
0.14
0.12
0.25
0.79
1.5
0.15
31
1.8
0.35
Maximum
Monthly Avg.
(mg/L (ppm))
31
26
59
4.3
0.09
0.55
0.57
0.13
0.07
0.09
0.10
0.49
0.64
0.06
13
1.4
0.17
As explained in Section 15.2.7, upon agreement with the permitting authority,
facilities with cyanide treatment have the option of achieving the limitation for either total or
amenable cyanide. Additionally, upon agreement with the permitting authority, facilities must
choose to monitor for TOP or TOC, or implement a management plan for organic chemicals as
specified in Section 15.2.7.
14.1.3
BPT Technology Selection for Non-Chromium Anodizing Subcategory
Section 6.2.3 describes the Non-Chromium Anodizing Subcategory. EPA's
survey of the MP&M industry did not identify any non-chromium anodizing facilities
discharging directly to surface waters. All of the non-chromium anodizing facilities in EPA's
data base are either indirect or zero dischargers. EPA consequently could not evaluate any
treatment systems in place at direct discharging non-chromium anodizing facilities for
establishing BPT limitations. Therefore, EPA relied on technology transfer based on information
14-10
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14.0 - Effluent Limitations and Standards
and data from indirect discharging facilities in the Non-Chromium Anodizing Subcategory. The
Agency concluded that the technology in place at some indirect discharging non-chromium
anodizing facilities is appropriate to use as the basis for regulation of direct dischargers because
the pollutant profile of the wastewater generated at those facilities discharging directly would be
similar in character to that from indirect discharging non-chromium anodizing facilities and the
model technologies in place at indirect dischargers are effective in treating the conventional
pollutants that are generally not regulated in pretreatment standards.
EPA previously promulgated BPT and BAT limitations for all of the facilities in
this subcategory at 40 CFR Part 433 (Metal Finishing Effluent Limitations Guidelines and
Pretreatment Standards). However, EPA developed the regulations applicable to this
subcategory approximately 20 years ago, and since that time, advances in anodizing processes,
water conservation, pollution prevention, and wastewater treatment have occurred. EPA is
proposing to set new BPT effluent limitations guidelines for this subcategory for metals, but is
not revising the limitations for conventional pollutants (TSS and oil and grease). EPA based its
decision not to revise the limitations for conventional pollutants on the small additional removals
attainable after the incidental removal due to control of the metals.
In addition, the current regulations in 4 |