United States
Environmental Protection
Agency
Office of \Afeter
(4303)
EPA-821-R-97-022
January 1998
Development Document
for Proposed Effluent
Limitations Guidelines and
Standards for the Landfills
Point Source Category
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DEVELOPMENT DOCUMENT
FOR
PROPOSED EFFLUENT LIMITATIONS
GUIDELINES AND STANDARDS
FOR THE
LANDFILLS
POINT SOURCE CATEGORY
Carol M. Browner
Administrator
Robert Perciasepe
Assistant Administrator, Office of Water
Tudor T. Davies
Director, Office of Science and Technology
Sheila E. Frace
Acting Director, Engineering and Analysis Division
Elwood H. Forsht
Chief, Chemicals and Metals Branch
John Tinger and Michael C. Ebner
Project Managers
January 1998
U.S. Environmental Protection Agency
Office of Water
Washington, DC 20460
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ACKNOWLEDGEMENTS AND DISCLAIMER
This document has been reviewed and approved for publication by the Engineering Analysis Division,
Office of Science and Technology, U.S. Environmental Protection Agency. This document was
prepared with the support of Science Applications International Corporation under Contract 68-C5-
0041, under the direction and review of the Office of Science and Technology. 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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LANDFILLS DEVELOPMENT DOCUMENT
TABLE OF CONTENTS
1.0
LEGAL AUTHORITY 1-1
1.1 Legal Authority 1-1
1.2 Background 1-1
1.2.1 Clean Water Act (CWA) 1-1
1.2.1.1 Best Practicable Control Technology Currently Available
(BPT) 1-1
1.2.1.2 Best Conventional Pollutant Control Technology (BCT) 1 -2
1.2.1.3 Best Available Technology Economically Achievable
(BAT) 1-2
1.2.1.4 New Source Performance Standards (NSPS) 1-3
1.2.1.5 Pretreatment Standards for Existing Sources (PSES) . . 1-3
1.2.1.6 Pretreatment Standards for New Sources (PSNS) 1-4
1.2.2 Section 304(m) Requirements 1-4
2.0 SUMMARY AND SCOPE 2-1
2.1 Introduction 2-1
2.2 Subcategorization •. ; 2-1
2.3 Scope of Proposed Regulation 2-2
2.4 Best Practicable Control Technology Currently Available (BPT) 2-3
2.5 Best Conventional Pollutant Control Technology (BCT) 2-3
2.6 Best Available Technology Economically Achievable (BAT) 2-3
2.7 New Source Performance Standards (NSPS) 2-3
2.8 Pretreatment Standards for Existing Sources (PSES) 2-3
2.9 Pretreatment Standards for New Sources (PSNS) 2-4
3.0 INDUSTRY DESCRIPTION 3-1
3.1 Regulatory History of the Landfills Industry 3-3
3.1.1 RCRA Subtitle C 3-3
3.1.1.1 Land Disposal Restrictions 3-4
3.1.1.2 Minimum Technology Requirements 3-6
3.1.2 RCRA Subtitle D 3-6
3.1.2.1 40 CFR Part 257, Subpart A Criteria 3-7
3.1.2.2 40 CFR Part 258 Revised Criteria for Municipal 'Solid
Waste Landfills 3-7
3.1.2.3 40 CFR Part 257, Subpart B Conditionally Exempt Small
Quantity Generator Revised Criteria 3-9
3.1.3 Current Wastewater Regulations 3-9
3.2 Industry Profile 3-10
3.2.1 Industry Population 3-11
3.2.2 Number and Location of Facilities 3-11
3.2.2.1 Captive Landfill Facilities 3-12
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TABLE OF CONTENTS
3.2.3 General Information on Landfill Facilities 3-13
3.2.4 Waste Receipts and Types 3-14
3.2.5 Sources of Wastewater 3-16
3.2.5.1 Landfill Leachate 3-16
3.2.5.2 Landfill Gas Condensate 3-16
3.2.5.3 Truck/Equipment Washwater 3-17
3.2.5.4 Drained Free Liquids 3-17
3.2.5.5 Laboratory-Derived Wastewater 3-18
3.2.5.6 Recovering Pumping Wells 3-18
3.2.5.7 Contaminated Ground-water 3-18
3.2.5.8 Storm Water 3-19
3.2.6 Leachate Collection Systems 3-19
3.2.7 Pretreatment Methods 3-20
3.2.8 Baseline Treatment 3-21
3.2.9 Discharge Types 3-22
4.0 DATA COLLECTION ACTIVITIES .4-1
4.1 Introduction 4-1
4.2 Preliminary Data Summary 4-1
4.3 Clean Water Act Section 308 Questionnaires 4-3
4.3.1 Screener Surveys 4-4
4.3.1.1 Recipient Selection and Mailing 4-4
4.3.1.2 Information Collected 4-5
4.3.1.3 Data Entry, Coding, and Analysis 4-6
4.3.1.4 Mailout Results 4-6
4.3.2 Detailed Technical Questionnaires 4-7
4.3.2.1 Recipient Selection and Mailing 4-7
4.3.2.2 Information Collected 4-8
4.3.2.3 Data Entry, Coding, and Analysis 4-9
4.3.2.4 Mailout Results 4-9
4.4 Detailed Monitoring Questionnaire 4-9
4.4.1 Recipient Selection and Mailing 4-10
4.4.2 Information Collected 4-10
4.4.3 Data Entry, Coding, and Analysis 4-10
4.5 Engineering Site Visits - 4-10
4.6 Wastewater Characterization Site Visits 4-11
4.7 EPA Week-Long Sampling Program 4-12
4.8 Other Data Sources 4-13
4.8.1 Industry Supplied Data 4-13
4.8.2 Comprehensive Environmental Response, Compensation and Liability Act
(CERCLA)/Superfund Amendments and Reauthorization Act (SARA)
Groundwater Data 4-13
4.8.3 POTW Study 4-14
11
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TABLE OF CONTENTS
4.8.4 National Risk Management Research Laboratory Data 4-15
4.9 QA/QC and Other Data Editing Procedures 4-15
4.9.1 QA/QC Procedures 4-16
4.9,2 Analytical Database Review 4-16
4.9.2.1 Data Review Narratives 4-16
4.9.2.2 Completeness Checks 4-16
4.9.2.3 Trip Blanks and Equipment Blanks 4-17
4.9.2.4 Field Duplicates 4-18
4.9.2.5 Grab Samples 4-19
4.9.2.6 Non-Detect Data 4-19
4.9.2.7 Bi-Phasic Samples 4-19
4.9.2.8 Conversion of Weight/Weight Data 4-20
4.9.2.9 Average Concentration Data 4-21
4.9.3 Detailed Questionnaire Database Review 4-21
4.9.4 Detailed Monitoring Questionnaire Review 4-22
5.0 INDUSTRY SUBCATEGORIZATION 5-1
5.1 Subcategorizatiori Approach 5-1
5.2 Proposed Subcategories 5-2
5.3 Other Factors Considered for Basis of Subcategorization 5-2
5.3.1 Types of Wastes Received 5-3
• 5.3.2 Wastewater Characteristics 5-5
5.3.3 Facility Size 5-6
5.3.4 Ownership . 5-7
5.3.5 Geographic Location 5-7
5.3.6 Facility Age 5-8
5.3.7 Economic Characteristics 5-9
5.3.8 Treatment Technologies and Costs 5-10
5.3.9 Energy Requirements . 5-10
5.3.10 Non-Water Quality Impacts 5-11
6.0 WASTEWATER GENERATION AND CHARACTERIZATION 6-1
6.1 Wastewater Generation and Sources of Wastewater 6-1
6.2 Wastewater Flow and Discharge 6-5
6.2.1 Wastewater Flow and Discharge at Subtitle D
Non-Hazardous Landfills 6-6
6.2.2 Wastewater Flow and Discharge at Subtitle C Hazardous Landfills ... 6-6
6.3 Wastewater Characterization 6-7
6.3.1 Background Information 6-8
6.3.1.1 Landfill Leachate 6-8
6.3.1.1.1 Additional Sources of Non-Hazardous Leachate
Characterization Data 6-11
6.3.1.2 Landfill Gas Condensate 6-13
111
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TABLE OF CONTENTS
6.3.1.3 Truck and Equipment Washwater 6-14
6.3.1.4 Drained Free Liquids 6-14
6.3.2 Pollutant Parameters Analyzed at EPA Sampling Episodes 6-15
6.3.3 Raw Wastewater Characterization Data 6-16
6.3.4 Conventional, Toxic, and Selected Nonconventional Pollutant
Parameters 6-17
6.3.5 Toxic Pollutants and Remaining Nonconventional Pollutants 6-19
6.3.6 Raw Wastewater at Subtitle D Non-Hazardous Landfills 6-20
6.3.6.1 Raw Wastewater at Subtitle D Non-Hazardous Landfills:
Municipal 6-20
6.3.6.2 Raw Wastewater at Subtitle D Non-Hazardous Landfills:
Non-Municipal 6-20
6.3.6.3 Dioxins and Furans in Raw Wastewater at Subtitle D Non-
Hazardous Landfills 6-22
6.3.7 Raw Wastewater at Subtitle C Hazardous Landfills 6-23
6.3.7.1 Dioxins and Furans in Raw Wastewater at Subtitle C
Hazardous Landfills 6-23
7.0 POLLUTANT PARAMETER SELECTION 7-1
7.1 Introduction 7-1
7.2 Pollutants Considered for Regulation 7-1
7.3 Selection of Pollutants of Interest 7-2
7.4 Development of Pollutant Discharge Loadings 7-3
7.4.1 Development of Current Discharge Concentrations 7-4
7.4.1.1 Alternate Methodology for Subtitle D Non-Hazardous
Subcategory: Non-Municipal 7-5
7.4.1.2 Alternate Methodology for Subtitle C Hazardous
Subcategory 7-6
7.4.2 Development of Pollutant Mass Loading Values 7-7
7.5 Assessment of Pollutants of Interest 7-8
7.6 Selection of Pollutants to be Regulated for Direct Dischargers 7-9
7.6.1 Non-Hazardous Subcategory Pollutants to be Regulated for Direct
Dischargers 7-9
7.6.2 Hazardous Subcategory Pollutants to be Regulated for Direct
Dischargers ''. : 7-14
7.7 Selection of Pollutants to be Regulated for Indirect Dischargers 7-21
7.7.1 Pass-Through Analysis for Indirect Dischargers 7-21
7.7.2 Non-Hazardous Subcategory Pollutants to be Regulated for Indirect
Dischargers 7-22
7.7.3 Hazardous Subcategory Pollutants to be Regulated for Indirect
Dischargers 7-23
8.0 WASTEWATER TREATMENT TECHNOLOGY DESCRIPTION 8-1
IV
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TABLE OF CONTENTS
8.1 Available BAT and PSES Technologies 8-1
8.1.1 Best Management Practices 8-1
8.1.2 Physical/Chemical Treatment 8-2
8.1.2.1 Equalization 8-2
8.1.2.2 Neutralization 8-4
8.1.2.3 Flocculation 8-4
8.1.2.4 Gravity Assisted Separation 8-5
8.1.2.5 Chemical Precipitation 8-8
8.1.2.6 Chemical Oxidation/Reduction 8-10
8.1.2.7 Stripping 8-11
8.1.2.7.1 Air Stripping , 8-12
8.1.2.8 Filtration 8-12
8.1.2.8.1 Sand Filtration 8-13
8.1.2.8.2 Diatomaceous Earth 8-14
8.1.2.8.3 Multimedia Filtration 8-15
8.1.2.8.4 Membrane Filtration 8-16
8.1.2.8.4.1 Ultrafiltration 8-16
8.1.2.8.4.2 Reverse Osmosis 8-16
8.1.2.8.5 Fabric Filters 8-19
8.1.2.9 Carbon Adsorption 8-19
8.1.2.10 Ion Exchange 8-21
8.1.3 Biological Treatment 8-22
8.1.3.1 Lagoon Systems 8-24
8.1.3.2 Anaerobic Systems 8-27
8.1.3.3 Attached Growth Biological Treatment Systems .... 8-28
8.1.3.4 Activated Sludge 8-31
8.1.3.5 Powdered Activated Carbon Biological Treatment ... 8-36
8.1.3.6 Sequencing Batch Reactors (SBRs) 8-37
8.1.3.7 Nitrification Systems 8-38
8.1.3.8 Denitrification Systems 8-38
8.1.3.9 Wetlands Treatment 8-39
8.1.4 Sludge Handling 8-39
8.1.4.1 Sludge Slurrying 8-40
8.1.4.2 Gravity Thickening 8-40
8.1.4.3 Pressure Filtration ..; 8-40
8.1.4.4 Sludge Drying Beds 8-41
8.1.5 Zero Discharge Treatment Options 8-42
8.2 Treatment Performance 8-43
8.2.1 Performance of EPA Sampled Treatment Processes 8-43
8.2.1.1 Treatment Performance for Episode 4626 8-44
8.2.1.2 Treatment Performance for Episode 4667 8-46
8.2.1.3 Treatment Performance for Episode 4721 8-47
8.2.1.4 Treatment Performance for Episode 4759 8-48
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TABLE OF CONTENTS
8.2.1.5 Treatment Performance for Episode 4687 8-49
9.0 ENGINEERING COSTS 9-1
9.1 Evaluation of Cost Estimation Techniques 9-1
9.1.1 Cost Models 9-1
9.1.2 Vendor Data 9-3
9.1.3 Other EPA Effluent Guideline Studies 9-3
9.1.4 Benchmark Analysis and Evaluation Criteria 9-3
9.1.5 Selection of Final Cost Estimation Techniques 9-5
9.2 Engineering Costing Methodology 9-6
9.2.1 Treatment Costing Methodology 9-7
9.2.1.1 Retrofit Costs 9-9
9.2.2 Land Costs 9-9
9.2.3 Residual Disposal Costs 9-9
9.2.4 Permit Modification Costs 9-10
9.2.5 Monitoring Costs 9-10
9.2.6 Off-Site Disposal Costs 9-11
9.3 Development of Cost Estimates for Individual Treatment Technologies .... 9-11
9.3.1 Equalization 9-12
9.3.2 Flocculation 9-13
9.3.3 Chemical Feed Systems 9-14
Sodium Hydroxide Feed Systems 9-15
Phosphoric Acid Feed Systems 9-17
Polymer Feed Systems 9-18
9.3.4 Primary Clarification 9-19
9.3.5 Activated Sludge Biological Treatment 9-20
9.3.6 Secondary Clarification 9-22
9.3.7 Multimedia Filtration 9-23
9.3.8 Reverse Osmosis 9-24
9.3.9 Sludge Dewatering 9-25
9.4 Costs for Regulatory Options 9-26
9.4.1 BPT Regulatory Costs 9-26
9.4.1.1 Subtitle D Non-Hazardous Subcategory BPT Costs 9-26
9.4.1.2 Subtitle C Hazardous Subcategory BPT Costs 9-27
9.4.2 BCT Regulatory Costs 9-27
9.4.2.1 Subtitle D Non-Hazardous Subcategory BCT Costs 9-28
9.4.2.2 Subtitle C Hazardous Subcategory BCT Costs 9-28
9.4.3 BAT Regulatory Costs 9-28
9.4.3.1 Subtitle D Non-Hazardous Subcategory BAT Costs 9-28
9.4.3.2 Subtitle C Hazardous Subcategory BAT Costs 9-29
9.4.4 PSES Regulatory Costs 9-29
9.4.4.1 Subtitle D Non-Hazardous Subcategory PSES Costs 9-30
VI
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TABLE OF CONTENTS
9.4.4.2 Subtitle C Hazardous Subcategory PSES Costs 9-30
9.4.5 NSPS Regulatory Costs 9-30
9-4.5.1 Subtitle D Non-Hazardous Subcategory NSPS Costs 9-30
9.4.5.2 Subtitle C Hazardous Subcategory NSPS Costs 9-31
9.4.6 PSNS Regulatory Costs 9-31
9.4.6.1 Subtitle D Non-Hazardous Subcategory PSNS Costs 9-31
9.4.6.2 Subtitle C Hazardous Subcategory PSNS Costs 9-31
10.0 NON-WATER QUALITY IMPACTS 10-1
10.1 Air Pollution 10-1
10.2 Solid and Other Aqueous Wastes 10-3
10.3 Energy Requirements 10-4
11.0 DEVELOPMENT OF EFFLUENT LIMITATIONS GUIDELINES
AND STANDARDS 11-1
11.1 Development of Long Term Averages, Variability Factors, and Effluent
Limitations ,. 11-1
11.1.1 Calculation of Long Term Averages 11-2
11.1.2 Calculation of Variability Factors ... 11-4
11.1.3 Calculation of Effluent Limitations - 11-5
11.2 Best Practicable Control Technology Currently Available (BPT) 11-6
11.2.1 BPT Technology Options for the Subtitle D Non-Hazardous
Subcategory 11-7
11.2.2 BPT Limits for the Subtitle D Non-Hazardous Subcategory 11-10
11.2.3 BPT Technology Options for the Subtitle C Hazardous Subcategory 11-15
11.2.4 BPT Limits for the Subtitle C Hazardous Subcategory 11-18
11.3 Best Conventional Pollutant Control Technology (BCT) 11-19
11.4 Best Available Technology Economically Achievable (BAT) 11-20
11.4.1 BAT Limits for the Subtitle D Non-Hazardous Subcategory 11-21
11.4.2 BAT Limits for the Subtitle C Hazardous Subcategory 11-22
11.5 New Source Performance Standards (NSPS) 11-23
11.6 Pretreatment Standards for Existing Sources (PSES) 11-23
11.6.1 PSES Limits for the Subtitle D Non-Hazardous Subcategory 11-24
11.6.2 PSES Limits for the Subtitle C Hazardous Subcategory 11-27
11.7 Pretreatment Standards for New Sources (PSNS) 11-29
12.0 REFERENCES 12-1
APPENDIX A
APPENDIX B
INDEX
Section 308 Survey for Landfills - Industry Population Analysis
Definitions, Acronyms, and Abbreviations
Vll
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LIST OF TABLES
2-1 Proposed Concentration Limitations for Hazardous Landfill Subcategory, Direct
Discharges 2-5
2-2 Proposed Concentration Limitations for Hazardous Landfill Subcategory, Indirect
Discharges 2-6
2-3 Proposed Concentration Limitations for Non-Hazardous Landfill Subcategory, Direct
Discharges 2-7
3-1 Number of Landfills per U.S. State 3-23
3-2 Ownership Status of Landfill Facilities 3-24
3-3 Total Landfill Facility Area 3-25
3-4 Landfill Facility Land Area Ranges 3-26
3-5 Number of Landfill Cells 3-27
3-6 Household and Non-Household Population Served 3-28
3-7 Household vs. Non-Household Customers 3-29
3-8 Wastes Received by Landfills in the United States 3-30
3-9 Total Volume of Waste Received by Landfills in 1992 by Regulatory Classification . 3-31
3-10 Annual Tonnage of Waste Accepted by Landfills 3-32
3-11 Wastewater Flows Generated by Individual Landfills 3-33
3-12 Type of Leachate Collection Systems Used at Individual Landfills 3-34
3-13 Pretreatment Methods in Use at Individual Landfills 3-35
3-14 Types of Wastewater Treatment Employed by the Landfills Industry 3-36
3-15 Wastewater Treatment Facility Hours of Operation per Day 3-37
3-16 Wastewater Treatment Facility Average Hours of Operation per Day 3-38
3-17 Wastewater Treatment Facility Days of Operation per Week 3-39
3-18 Wastewater Treatment Facility Average Days of Operation per Week 3-40
3-19 Total Number of Facilities by Discharge Type 3-41
4-1 Screener Questionnaire Strata 4-5
4-2 Types of Facilities Included in EPA's Characterization and Engineering Site Visits .. 4-23
4-3 Types of Facilities Included in EPA's Week-Long Sampling Program 4-24
5-1 Subtitle D Non-Hazardous Landfill Data Comparison 5-12
5-2 Hazardous and Non-Hazardous Groundwater Results 5-14
5-3 Comparison of Untreated Wastewater Characteristics at Landfills of Vary ing Age .. 5-17
6-1 Wastewater Generation in 1992: Hazardous and Non-Hazardous Subcategory 6-25
6-2 Quantity of In-Scope Wastewater Generated in 1992 6-29
6-3 Contaminant Concentration Ranges in Municipal Leachate as Reported in Literature
Sources 6-30
6-4 Landfill Gas Condensate (from Detailed Questionnaire) 6-31
6-5 EPA Sampling Episode Pollutants Analyzed 6-32
6-6 EPA Sampling Episode List of Analytes Never Detected 6-36
6-7 Subtitle D Non-Hazardous Subcategory Master File 6-43
6-8 Subtitle C Hazardous Subcategory Master File 6-44
6-9 Range of Conventional and Selected Nonconventional Pollutants Raw Wastewater
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LIST OF TABLES
Concentrations 6-45
6-10 Range of Metals and Toxic Pollutants Raw Wastewater Concentrations 6-46
6-11 Range of Organic Pollutants Raw Wastewater Concentrations 6-47
6-12 Dioxins and Furans at Non-Hazardous EPA Sampling Episodes by Episode and Sample
Point 6-48
6-13 Dioxins and Furans at Hazardous EPA Sampling Episodes by Episode and Sample
Point 6-49
7-1 Non-Hazardous Subcategory Pollutants of Interest 7-24
7-2 Hazardous Subcategory Pollutants of Interest 7-25
7-3 Pass-Through Analysis for Pollutants to be Regulated in the Hazardous Subcategory 7-26
8-1 Wastewater Treatment Technologies Employed at In-Scope Landfill Facilities 8-51
8-2 Treatment Technology Performance for Facility 4626 - Subtitle D Municipal 8-52
8-3 Treatment Technology Performance for Facility 4667 - Subtitle D Municipal 8-53
8-4 Treatment Technology Performance for Facility 4721 - Subtitle C Hazardous .... 8-54
8-5 Treatment Technology Performance for Facility 4759 - Subtitle C Hazardous .... 8-56
8-6 Treatment Technology Performance for Facility 4687 - Subtitle D Municipal 8-58
9-1 Cost Comparison 9-33
9-2 Costing Source Comparison 9-34
9-3 Breakdown of Costing Method by Treatment Technology 9-35
9-4 Additional Cost Factors 9-36
9-5 Analytical Monitoring Costs , 9-37
9-6 Subtitle D Non-Hazardous Facilities Costed for Off-Site Disposal 9-38
9-7 Unit Process Breakdown by Regulatory Option 9-39
9-8 Chemical Addition Design Method 9-40
9-9 Treatment Chemical Costs 9-41
9-10 Sodium Hydroxide Requirements for Chemical Precipitation 9-42
9-11 BPT/BCT/BAT Option I Subtitle D Non-Hazardous Subcategory 9-43
9-12 BPT/BCT/BAT Option II Subtitle D Non-Hazardous Subcategory 9-54
9-13 BAT Option III Subtitle D Non-Hazardous Subcategory 9-65
9-14 PSES Option I Subtitle D Non-Hazardous Subcategory 9-76
11-1 Removal of Pollutant of Interest Metals in the Non-Hazardous Subcategory 11-30
11-2 List of Subtitle D Municipal Solid Waste Facilities Employing Biological Treatment
Considered for BPT hi the Non-Hazardous Subcategory 11-31
11-3 Comparison of Raw Wastewater Mean Concentrations of Non-Hazardous Pollutants of
Interest for Municipal Solid Waste Landfills and Hazardous Facility 16041 11-32
11 -4 Candidate BPT Facilities for the Non-Hazardous Subcategory Without BOD5 Effluent
Data 11-33
11-5 Landfill Facilities Considered for BPT in the Non-Hazardous Subcategory which Supplied
BODS Effluent Data . . 11-34
11-6 National Estimates of Pollutant of Interest Reductions for BPT/B AT Options for Municipal
Solid Waste Landfills - Direct Dischargers 11-35
11-7 National Estimates of Pollutant of Interest Reductions for BPT/B AT Options for Non-
Municipal Solid Waste Landfills - Direct Dischargers 11-36
IX
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LIST OF TABLES
11-8 Annual Pollutant Discharge Before and After the Implementation of BPT for Subtitle D
Municipal Solid Waste Landfill Facilities in the Non-Hazardous Subcategory 11-37
11-9 Annual Pollutant Discharge Before and After the Implementation of BPT for Subtitle D Non-
Municipal Landfill Facilities in the Non-Hazardous Subcategory 11-38
11-10 BPT Limitations for the Non-Hazardous Subcategory 11-39
11-11 BPT Limitations for the Hazardous Subcategory 11-40
11-12 Comparison of Long Term Averages for Nonconventional and Toxic Pollutants Proposed to
be Regulated under BPT and BAT 11-41
11-13 Comparison of Ammonia Concentrations in Wastewaters 11-42
11-14 National Estimates of Pollutant of Interest Reductions for PSES/PSNS Options for Municipal
Solid Waste Landfills - Indirect Dischargers 11-43
11-15 National Estimates of Pollutant of Interest Reductions for PSES/PSNS Option I for Non-
Municipal Solid Waste Landfills - Indirect Dischargers 11-44
11-16 PSES and PSNS Limitations for the Hazardous Subcategory 11-45
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LIST OF FIGURES
3-1 Development of National Estimates for the Landfills Industry 3-42
7-1 Development of Pollutants of Interest 7-27
7-2 Selection of Pollutants to be Regulated 7-28
8-1 Equalization 8-59
8-2 Neutralization 8-59
8-3 Clarification System Incorporating Coagulation and Flocculation 8-60
8-4 Calculated Solubilities of Metal Hydroxides 8-61
8-5 Chemical Precipitation System Diagram 8-62
8-6 Cyanide Destruction 8-63
8-7 Chromium Reduction 8-64
8-8 Typical Air Stripping System 8-65
8-9 Multimedia Filtration 8-66
8-10 Ultrafutration System Diagram 8-67
8-11 Tubular Reverse Osmosis Module 8-68
8-12 Granular Activated Carbon Adsorption 8-69
8-13 Ion Exchange 8-70
8-14 Aerated Lagoon 8-71
8-15 Facultative Pond ' 8-72
8-16 Completely Mixed Digester System 8-73
8-17 Rotating Biological Contactor Cross-Section 8-74
8-18 Trickling Filter 8-75
8-19 Fluidized Bed Reactor 8-76
8-20 Activated Sludge System 8-77
8-21 Powdered Activated Carbon Treatment System 8-78
8-22 Sequencing Batch Reactor Process Diagram 8-79
8-23 Gravity Thickening 8-80
8-24 Plate and Frame Pressure Filtration System Diagram 8-81
8-25 Drying Bed 8-82
8-26 EPA Sampling Episode 4626 - Landfill Waste Treatment System Block Flow Diagram with
Sampling Locations 8-83
8-27 EPA Sampling Episode 4667 - Landfill Waste Treatment System Block Flow Diagram with
Sampling Locations 8-84
8-28 EPA Sampling Episode 4721 - Landfill Waste Treatment System Block Flow Diagram with
Sampling Locations 8-85
8-29 EPA Sampling Episode 4759 - Landfill Waste Treatment System Block Flow Diagram with
Sampling Locations 8-86
8-30 EPA Sampling Episode 4687 - Landfill Waste Treatment System Block Flow Diagram with
Sampling Locations 8-87
XI
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LIST OF FIGURES
9-1 Option Specific Costing Logic Flow Diagram 9-87
9-2 Equalization Capital Cost Curve 9-88
9-3 Flocculation Capital Cost Curve 9-89
9-4 Flocculation O&M Cost Curve 9-90
9-5 Sodium Hydroxide Capital Cost Curve 9-91
9-6 Sodium Hydroxide O&M Cost Curve 9-92
9-7 Phosphoric Acid Feed Capital Cost Curve 9-93
9-8 Phosphoric Acid Feed O&M Cost Curve 9-94
9-9 Polymer Feed Capital Cost Curve 9-95
9-10 Polymer Feed O&M Cost Curve 9-96
9-11 Primary Clarifier Capital Cost Curve 9-97
9-12 Primary Clarifier O&M Cost Curve 9-98
9-13 Aeration Basin Capital Cost Curve 9-99
9-14 Air Diffusion System Capital Cost Curve 9-100
9-15 Air Diffusion System O&M Cost Curve 9-101
9-16 Secondary Clarifier Capital Cost Curve 9-102
9-17 Secondary Clarifier O&M Cost Curve 9-103
9-18 Multimedia Filtration Capital Cost Curve 9-104
9-19 Multimedia Filtration O&M Cost Curve 9-105
9-20 Reverse Osmosis Capital Cost Curve 9-106
9-21 Sludge Drying Beds Capital Cost Curve 9-107
9-22 Sludge Drying Beds O&M Cost Curve . 9-108
11-1 BPT/BCT/BAT/PSES/PSNS Non-Hazardous Subcategory Option I Flow Diagram 11-46
11-2 BPT/BCT/BAT Non-Hazardous Subcategory Option II & NSPS Flow Diagram .. 11-47
11-3 BPT/BCT/BAT/PSES Hazardous Subcategory Option I & NSPS/PSNS Flow
Diagram 11-48
11-4 BAT Hazardous Subcategory Option III Flow Diagram 11-49
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1.0 LEGAL AUTHORITY
1.1 Legal Authority
Effluent limitations guidelines and standards for the Landfills industry are being proposed under the
authority of Sections 301, 304, 306, 307, 308, and 501 of the Clean Water Act, 33 U.S.C. 1311,
1314, 1316, 1317, 1318, and 1361.
1.2 Background
1.2.1 Clean Water Act (CWA)
The Federal Water Pollution Control Act Amendments of 1972 established a comprehensive program
to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters"
(Section 101(a)). To implement the Act, EPA is to issue effluent limitations guidelines, pretreatment
standards, and new source performance standards for industrial dischargers. These guidelines and
standards are summarized briefly in the following sections.
1.2.1.1 Best Practicable Control Technology Currently Available (BPT)
(Section 304(b)(l) of the CWA)
In the guidelines for an industry category, EPA defines BPT effluent limits for conventional, priority,1
and non-conventional pollutants. In specifying BPT, EPA looks at a number of factors. EPA first
considers the cost of achieving effluent reductions in relation to the effluent reduction benefits. The
Agency also considers: the age of the equipment and facilities; the processes employed and any
required process changes; engineering aspects of the control technologies; non-water quality
'In the initial stages of EPA CWA regulation, EPA efforts emphasized the achievement of BPT
limitations for control of the "classical" pollutants (e.g., TSS, pH, BOD5). However, nothing on *
the face of the statute explicitly restricted BPT limitation to such pollutants. Following passage of
the Clean Water Act of 1977 with its requirement for points sources to achieve best available
technology limitations to control discharges of toxic pollutants, EPA shifted its focus to address
the listed priority pollutants under the guidelines program. BPT guidelines continue to include
limitations to address all pollutants.
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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 characteristic. Where, however, 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.
1.2.1.2 Best Conventional Pollutant Control Technology (BCT)
(Section 304(b)(4) of the CWA)
The 1977 amendments to the CWA required EPA to identify effluent reduction levels for
conventional pollutants associated with BCT technology for discharges from existing industrial point
sources. In addition to other factors specified in Section 304(b)(4)(B), the CWA requires that EPA
establish BCT limitations after consideration of a two part "cost-reasonableness" test. EPA explained
its methodology for the development of BCT limitations in July 1986 (51 FR 24974).
Section 304(a)(4) designates the following as conventional pollutants: biochemical oxygen demand
(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).
1.2.1.3 Best Available Technology Economically Achievable (BAT)
(Section 304(b)(2) of the CWA)
In general, BAT effluent limitations guidelines represent the best economically achievable
performance of plants in the industrial subcategory or category. The factors considered in assessing
BAT include the cost of achieving BAT effluent reductions, the age of equipment and facilities
> involved, the process employed, potential process changes, and non-water quality environmental
impacts, including energy requirements. The Agency retains considerable discretion in assigning the
weight to be accorded these factors. Unlike BPT limitations, BAT limitations may be based on
effluent reductions attainable through changes in a facility's processes and operations. As with BPT,
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where existing performance is uniformly inadequate, BAT may require a higher level of performance
than is currently being achieved based on technology transferred from a different subcategory or
category. BAT may be based upon process changes or internal controls, even when these
technologies are not common industry practice.
1.2.1.4 New Source Performance Standards (NSPS)
(Section 306 of the CWA)
NSPS reflect effluent reductions that are achievable based on the best available demonstrated control
technology. New facilities have the opportunity to install the best and most efficient production
processes and wastewater treatment technologies. As a result, NSPS should represent the most
stringent controls attainable through the application of the best available control technology for all
pollutants (i.e., conventional, nonconventional, and priority pollutants). In establishing NSPS, EPA
is directed to take into consideration the cost of achieving the effluent reduction and any non-water
quality environmental impacts and energy requirements.
1.2.1.5 Pretreatment Standards for Existing Sources (PSES)
(Section 307(b) of the CWA)
PSES are designed to prevent the discharge of pollutants that pass through, interfere-with, or are
otherwise incompatible with the operation of publicly-owned treatment works (POTWs). The CWA
authorizes EPA to establish pretreatment standards for pollutants that pass through POTWs or
interfere with treatment processes or sludge disposal methods at POTWs. Pretreatment standards
are technology-based and analogous to BAT effluent limitations guidelines.
The General Pretreatment Regulations, which set forth the 'framework for the implementation of
categorical pretreatment standards, are found at 40 CFR Part 403. Those regulations contain a
definition of pass-through that addresses localized rather than national instances of pass-through and
establish pretreatment standards that apply to all non-domestic dischargers (see 52 FR 1586, January
14,1987).
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1.2.1.6 Pretreatment Standards for New Sources (PSNS)
(Section 307(b) of the CWA)
Like PSES, PSNS are designed to prevent the discharges of pollutants that pass through, interfere-
with, or are otherwise incompatible with the operation of POTWs. PSNS are to be issued at the same
time as NSPS. New indirect dischargers have the opportunity to incorporate into their plants the best
available demonstrated technologies. The Agency considers the same factors in promulgating PSNS
as it considers in promulgating NSPS.
1.2.2 Section 304(m) Requirements
Section 304(m) of the CWA, added by the Water Quality Act of 1987, requires EPA to establish
schedules for (1) reviewing and revising existing effluent limitations guidelines and standards
("effluent guidelines") and (2) promulgating new effluent guidelines. On January 2, 1990, EPA
published an Effluent Guidelines Plan (55 FR 80) that established schedules for developing new and
revised effluent guidelines for several industry categories. One of the industries for which the Agency
established a schedule was the Centralized Waste Treatment industry.
The Natural Resources Defense Council (NRDC) and Public Citizen, Inc. filed suit against the
Agency, alleging violation of Section 304(m) and other statutory authorities requiring promulgation
of effluent guidelines rNRDC et al. v. Reillv. Civ. No. 89-2980 (D.D.C.V). Under the terms of a
consent decree dated January 31,1992, which settled the litigation, EPA agreed, among other things,
to propose effluent guidelines for the "Landfills and Industrial Waste Combusters" category2 by
December 1995 and take final action on these effluent guidelines by December 1997. On February
4, 1997, the court approved modifications to the Decree which revise the deadlines to November
1997 for proposal and November 1999 for final action. EPA provided notice of these modifications
on February 26,1997, at 62 FR 8726. Although the Consent Decree lists "Landfills and Industrial
2 In the 1990 304(m) plan and the 1992 Decree, the category name was "Hazardous Waste
Treatment, Phase II", subsequently renamed as "Landfills and Industrial Waste Combusters."
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Waste Combusters" as a single entry, EPA is publishing separate rulemaking proposals for Industrial
Waste Combusters and for Landfills.
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2.0 SUMMARY AND SCOPE
2.1 Introduction
The proposed regulations for the Landfills industry include effluent limitations guidelines and
standards for the control of wastewater pollutants. This document presents the information and
rationale supporting these proposed effluent limitations guidelines and standards. Section 2.2
presents the proposed subcategorization approach, Section 2.3 describes the scope of the proposed
regulations, and Section 2.4 through 2.9 summarizes the proposed effluent limitations and standards.
2.2 Subcategorization
EPA is proposing to subcategorize the landfills category according to the landfill classifications
established under the Resource Conservation and Recovery Act (RCRA). These subcategories are
summarized below:
Subcategory I: Subtitle D Non-Hazardous Landfills
Subcategory I would apply to wastewater discharges from all landfills classified as RCRA Subtitle
D non-hazardous landfills subject to either of the criteria established in 40 CFR Parts 257 (Criteria
for Classification of Solid Waste Disposal Facilities and Practices) or 258 (Criteria for Municipal
Solid Waste Landfills).
Subcategory II: Subtitle C Hazardous Landfills
Subcategory II would apply to wastewater discharges from a solid waste disposal facility subject to
the criteria in 40 CFR 264 Subpart N - Standards for Owners and Operators of Hazardous Waste
Treatment, Storage, and Disposal Facilities and 40 CFR 265 Subpart N - Interim Standards for
Owners and Operators of Hazardous Waste Treatment, Storage, and Disposal Facilities.
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2.3 Scope of Proposed Regulation
EPA is proposing effluent limitations guidelines and pretreatment standards for wastewater discharges
associated only with the operation and maintenance of landfills regulated under Subtitles C and D of
the Resource Conservation and Recovery Act. EPA's proposal would not apply to wastewater
discharges associated with the operation and maintenance of land application or treatment units,
surface impoundments, underground injection wells, waste piles, salt dome or bed formations,
underground mines, caves or corrective action units. Additionally, this guideline would not apply to
waste transfer stations, or any wastewater not directly attributed to the operation and maintenance
of Subtitle C or Subtitle D landfill units. Consequently, wastewaters such as those generated in off-
site washing of vehicles used in landfill operations are not within the scope of this guideline.
The wastewater flows which are covered by the rule include leachate, gas collection condensate,
drained free liquids, laboratory-derived wastewater, contaminated storm water and contact washwater
from truck exteriors and surface areas which have come in direct contact with solid waste at the
landfill facility. Groundwater, however, which has been contaminated by a landfill and is collected,
treated, and discharged is excluded from this guideline.
EPA is proposing to exclude landfills operated in conjunction with other industrial or commercial
operations which only receive waste generated on site (captive facility) and/or receive waste from off-
site facilities under the same corporate structure (intra-company facility), so long as the wastewater
is commingled for treatment with other non-landfill process wastewaters. A landfill which accepts
off-site waste from a company not under the same ownership as the landfill would not be considered
a captive or intracompany facility and would be subject to the landfills category effluent guideline
when promulgated.
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2.4 Best Practicable Control Technology Currently Available (BPT)
EPA is proposing to establish BPT effluent limitations guidelines for conventional, priority, and non-
conventional pollutants for both subcategories. For RCRA Subtitle D non-hazardous waste landfills,
EPA proposes to establish effluent limitations standards based on equalization, biological treatment,
and multimedia filtration. For RCRA Subtitle C hazardous waste landfills, EPA proposes to establish
effluent limitations standards based on equalization, chemical precipitation, and biological treatment.
2.5 Best Conventional Pollutant Control Technology (BCT)
EPA is proposing to establish BCT effluent limitations guidelines equivalent to the BPT guidelines
for the control of conventional pollutants for both subcategories.
2.6 Best Available Technology Economically Achievable (BAT)
EPA is proposing to establish BAT effluent limitations guidelines equivalent to the BPT guidelines
for control of priority and non-conventional pollutants for both subcategories.
2.7 New Source Performance Standards (NSPS)
EPA is proposing to establish NSPS effluent limitations guidelines equivalent to the BPT, BCT, and
BAT guidelines for the control of conventional, priority and non-conventional pollutants for both
subcategories.
2.8 Pretreatment Standards for Existing Sources (PSES)
EPA is proposing to establish PSES standards for priority, and non-conventional pollutants for
Subtitle C hazardous landfills only. EPA is proposing to establish PSES standards based on
equalization, chemical precipitation, and biological treatment. EPA is not proposing to establish
PSES standards for Subtitle D non-hazardous landfills.
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2.9 Pretreatment Standards for New Sources (PSNS)
EPA is proposing to establish PSNS effluent limitations guidelines equivalent to PSES guidelines for
the control of priority and non-conventional pollutants for Subtitle C hazardous landfills. EPA is not
proposing to establish PSNS for Subtitle D non-hazardous landfills.
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Table 2-1: Proposed Concentration Limitations for Hazardous Landfill Subcategory,
Direct Discharges
Pollutant or
Pollutant Property
BOD5
TSS
Ammonia
Arsenic
Chromium (Total)
Zinc
Alpha Terpineol
Aniline
Benzene
Benzoic Acid
Naphthalene
P-Cresol
Phenol
Pyridine
Toluene
pH
Maximum for 1 day
(mg/1)
160
89
5.9
1.0
0.86
0.37
0.042
0.024
0.14
0.12
0.059
0.024
0.048
0.072
0.080
Monthly average shall not exceed
(mg/1) '
40
27
2.5
0.52
0.40
0.21
0.019
0.015
0.036
0.073
0.022
0.015
0.029
0.025
0.026
Shall be in the range 6.0 - 9.0 pH units.
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Table 2-2: Proposed Concentration Limitations for Hazardous Landfill Subcategory,
Indirect Discharges
Pollutant or
Pollutant Property
Ammonia
Alpha Terpineol
Aniline
Benzoic Acid
P-Cresol
Toluene
Maximum for 1 day
(mg/1)
5.9
6.042
0.024
0.12
0.024
0.080
Monthly average shall not exceed
(mg/1)
2.5
0.019
0.015
0.073
0.015 '
0.026
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Table 2-3: Proposed Concentration Limitations for Non-Hazardous Landfill Subcategory,
Direct Discharges
Pollutant or
Pollutant Property
BOD5
TSS
Ammonia
Zinc
Alpha Terpineol
Benzoic Acid
P-Cresol
Phenol
Toluene
PH
Maximum for 1 day
(mg/1)
160
89
5.9
0.20
0.059
0.23
6.046
0.045
0.080
Monthly average shall not exceed
(mg/1)
40
27
2.5
0.11
0.029
0.13
0.026
0.026
0.026
Shall be in the range 6.0 - 9.0 pH units.
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3.0 INDUSTRY DESCRIPTION
The Landfills industry consists of facilities that receive wastes either as commercial or municipal
operations, or as on-site (captive) operations owned by waste generators, and discharge wastewater
to surface waters and/or Publicly Owned Treatment Works (POTWs) as a result of these operations.
The Resource Conservation and Recovery Act (RCRA) defines a landfill as "an area of land or an
excavation in which wastes are placed for permanent disposal, and that is not a land application unit,
surface impoundment, injection well, or waste pile" (40 CFR 257.2). RCRA classifies landfills as
either Subtitle. C hazardous or Subtitle D non-hazardous. Wastewaters generated and discharged by
landfills can include leachate, gas collection condensate, contaminated groundwater, contaminated
storm water, drained free liquids, truck/equipment washwater, laboratory-derived wastewater, and
wastewaters recovered from pump wells.
Landfills are commonly classified by the types of wastes they accept and/or by their ownership status.
Some of the terms used to describe a landfill include municipal, sanitary, chemical, industrial, RCRA,
hazardous waste, Subtitle C, and Subtitle D. Although non-hazardous landfills do not knowingly
accept hazardous wastes, these facilities may contain hazardous wastes due to disposal practices that
occurred prior to 1980 and the enactment of RCRA and its associated regulations. The following
section includes definitions of the various types of landfills, landfill operations, and the wastes
processed in each:
Ownership Status
• Municipal:
Commercial:
Municipally owned landfills are those "that are owned by local governments.
Municipally owned landfills may be designed to accept either Subtitle D or
Subtitle C wastes (see "Regulatory Type").
Commercial landfills are privately owned facilities and can be designed to
receive either municipal, hazardous, or non-hazardous industrial wastes.
Typical non-hazardous industrial wastes include packaging and shipping
materials, construction and demolition debris, ash, and sludge.
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Captive:
Intra-company:
Regulatory Type
• Subtitle C:
Subtitle D:
Captive sites are landfill facilities operated in conjunction with other industrial
or commercial operations which only receive waste generated on-site.
Captive landfills are located on, or adjacent to, the facility they service and are
common at major hazardous waste generators, such as chemical and
petrochemical manufacturing plants.
Landfill facilities operated in conjunction with other industrial or commercial
operations which only receive waste from off-site facilities under the same
corporate structure, ownership, or control. These landfills are similar to
captive sites but are used to receive wastes from multiple locations of one
company.
Subtitle C landfills are those disposal operations authorized by RCRA to
accept hazardous wastes as defined in 40 CFR Part 261. Subtitle C hazardous
landfills are subject to the criteria in 40 CFR Subpart N (Standards for
Owners and Operators of Hazardous Waste Treatment, Storage, and Disposal
Facilities). More details on the regulatory requirements of Subtitle C are
presented in Section 3.1
Subtitle D landfills are those disposal operations that are authorized by RCRA
to receive municipal, commercial, or industrial wastes not defined as
hazardous or which are excluded from regulation under Subtitle C, as defined
in 40 CFR Parts 257 and 258. The wastes received at Subtitle D landfills
include municipal refuse, ash, sludge, construction and demolition debris, and
non-hazardous industrial waste. These facilities were not designed to receive
hazardous wastes; however, prior to 1980 and the enactment of RCRA, older
landfills may have received waste later classified as hazardous under RCRA.
Any Subtitle D landfill accepting municipal refuse after October 9, 1993 is
classified as a Municipal Waste Disposal Unit, and is regulated under 40 CFR
258. Any Subtitle D landfill not accepting municipal waste after October 9,
1993 continues to be regulated under 40 CFR 257. For the purposes of this
document, Subtitle D landfills not accepting municipal refuse are referred to
as "Subtitle D non-municipal" landfills.
The following discussions present a regulatory history of this industry and past EPA studies.
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3.1 Regulatory History of the Landfills Industry
Depending on the type of wastes disposed of at a landfill, the landfill may be subject to regulation and
permitting under either Subtitle C or Subtitle D of the Resource Conservation and Recovery Act
(RCRA). Subtitle C facilities receive wastes that are identified or listed as hazardous wastes under
EPA regulations. Subtitle D landfills can accept wastes that are not required to be sent to Subtitle
C facilities. The following sections outline some of the key regulations that have been developed to
control the environmental impacts of Subtitle C and Subtitle D landfills.
3.1.1 RCRA Subtitle C
Subtitle C of the RCRA of 1976 directed EPA to promulgate regulations to protect human health and
the environment from the improper management of hazardous wastes. Based on this statutory
mandate, the goal of the RCRA program was to provide comprehensive, "cradle-to-grave"
management of hazardous waste. These regulations establish a system for tracking the disposal of
hazardous wastes and special design requirements for landfills depending on whether a landfill
accepted hazardous or non-hazardous waste. Key statutory provisions in RCRA Subtitle C include:
Section 3001: Requires the promulgation of regulations identifying the characteristics of
hazardous waste and listing particular hazardous wastes.
Section 3002: Requires the promulgation of standards, such as manifesting, record keeping,
etc., applicable to generators of hazardous waste.
Section 3003: Requires the promulgation of standards, such as manifesting, record keeping,
etc., applicable to transporters of hazardous waste.
Section 3004: Requires the promulgation of performance standards applicable to the owners
and operators of facilities for the treatment, storage, or disposal of hazardous
waste.
Section 3005: Requires the promulgation of regulations requiring each person owning or
operating a treatment, storage, or disposal facility to obtain a permit.
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These regulations establish a system for tracking the disposal of hazardous wastes and performance
and design requirements for landfills accepting hazardous waste. Under RCRA, requirements are
initially triggered by a determination that a waste is hazardous as defined in 40 CFR Part 261. Any
party, including the original generator, that treats, stores, or disposes of a hazardous waste must
notify EPA and obtain an EPA identification number. There are existing performance regulations
governing the operation of hazardous waste landfills included in 40 CFR Parts 264 and 265. RCRA
Subtitle C hazardous waste regulations apply to landfills that presently accept hazardous wastes or
have accepted hazardous waste at any tune after November 19, 1980.
3.1.1.1
Land Disposal Restrictions
The Hazardous and Solid Waste Amendments (HSWA) to the RCRA, enacted on November 8, 1984,
largely prohibit the land disposal of untreated hazardous wastes. Once a hazardous waste is
prohibited from land disposal, the statute provides only two options for legal land disposal: 1) meet
the EPA-established treatment standard for the waste prior to land disposal, or 2) dispose of the
waste in a land disposal unit that has been found to satisfy the statutory no migration test. A no
migration unit is one from which there will be no migration of hazardous constituents for as long as
the waste remains hazardous. (RCRA Sections 3004 (d),(e),(g)(5)).
Under Section 3004, the treatment standards that EPA develops may be expressed as either
constituent concentration levels or as specific methods of treatment. Under RCRA Section
3004(m)(l), the criteria for these standards is that they must substantially diminish the toxicity of the
waste or substantially reduce the likelihood of migration of hazardous constituents from the waste
so that short-term and long-term threats to human health and the environment are minimized. For
purposes of the restrictions, the RCRA program defines land disposal to include, among other things,
any placement of hazardous waste in a landfill. Land disposal restrictions are published in 40 CFR
Part 268.
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EPA has vised hazardous waste treatability data as the basis for land disposal restrictions standards.
First, EPA has identified Best Demonstrated Available Treatment Technology (BDAT) for each listed
hazardous waste. BDAT is the treatment technology that EPA finds to be the most effective in
treating a waste and that also is readily available to generators and treaters. In some cases, EPA has
designated as BDAT for a particular waste stream a treatment technology shown to have successfully
treated a similar but more difficult to treat waste stream. This ensured mat the land disposal
restrictions standards for a listed waste stream were achievable since they always reflected the actual
treatability of the waste itself or of a more refractory waste.
As part of the Land Disposal Restrictions (LDRs), Universal Treatment Standards (UTS) were
promulgated as part of the RCRA phase two final rule (July 27,1994). The UTS are a series of
concentrations for wastewaters and non-wastewaters that provide a single treatment standard for each
constituent. Previously, the LDR regulated constituents according to the identity of the original
waste; thus several numerical treatment standards existed for each constituent. The UTS simplified
the standards by having only one treatment standard for each constituent in any waste residue. The
LDR and the UTS restricted the concentrations of wastes that could be disposed of in landfills, thus
improving the environmental quality of the leachate from landfills.
The LDR treatment standards established under RCRA may differ from the Clean Water Act effluent
guidelines both in their format and in the numerical values set for each constituent. The differences
result from the use of different legal criteria for developing the limits and resulting differences in the
technical and economic criteria and data sets used for establishing the respective limits.
The differences in format of the LDR and effluent guidelines are that the LDR establish a single daily
limit for each pollutant parameter whereas the effluent guidelines establish monthly and daily limits.
Additionally, the effluent guidelines provide for several types of discharge, including new and existing
sources, and indirect and direct discharge.
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The differences in numerical limits established under the Clean Water Act may differ not only from
LDR and UTS but also from point-source category to point-source category (e.g., Electroplating,
40 CFR 413; and Metal Finishing, 40 CFR 433). The effluent guidelines limitations and standards
are industry-specific, subcategory-specific, and technology-based. The numerical limits are typically
based on different data sets that reflect the performance of specific wastewater management and
treatment practices. Differences in the limits reflect differences in the statutory factors that the
Administrator is required to consider in developing technically and economically achievable
limitations and standards: manufacturing products and processes (which for landfills involves types
of waste disposed), raw materials, wastewater characteristics, treatability, facility size, geographic
location, age of facility and equipment, non-water quality environmental impacts, and energy
requirements. A consequence of these differing approaches is that similar or identical waste streams
are regulated at different levels dependent on the receiving body of the wastewater (e.g. a POTW,
a surface water, or a land disposal facility).
3.1.1.2
Minimum Technology Requirements
To further protect human health and the environment from the adverse affects of hazardous waste
disposed of in landfills, the 1984 HSWA to RCRA established minimum technology requirements
for landfills receiving hazardous waste. These provisions required the installation of double liners and
leachate collection systems at new landfills, at replacements of existing units, and at lateral expansions
of existing units. The Amendments also required all hazardous waste landfills to install groundwater
monitoring wells by November 8, 1987. Performance regulations governing the operation of
hazardous waste landfills are included 40 CFR Parts 264 and 265.
3.1.2 RCRA Subtitle D
Landfills managing non-hazardous wastes are currently regulated under the RCRA Subtitle D
program. These landfills include municipal, private intra-company, private captive, and commercial
facilities used for the management of municipal refuse, incinerator ash, sewage sludge, and a range
of industrial wastes.
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3.1.2.1 40 CFR Part 257, Subpart A Criteria
EPA promulgated these criteria on September 13, 1979 (44 FR 53460) under the authority of RCRA
Sections 1008(a) and 4004(a) and Sections 405(d) and (e) of the Clean Water Act. These criteria
apply to all solid waste disposal facilities and practices. However, certain facilities and practices are
not covered by the criteria, such as agricultural wastes returned to the soil as fertilizers or soil
conditioners; overburden resulting from mining operations; land application of domestic sewage or
treated domestic sewage; hazardous waste disposal facilities which are subject to regulations under
RCRA Subtitle C (discussed above); municipal solid waste landfills that are subject to the revised
criteria in 40 CFR Part 258 (discussed below); and use or disposal of sewage sludge on the land when
the sewage sludge is used or disposed of in accordance with 40 CFR Part 503 (See 40 CFR Part
The criteria include general environmental performance standards addressing eight major areas: flood
plains, protection of endangered species, protection of surface water, protection of groundwater,
limitations on the land application of solid waste, periodic application of cover to prevent disease
vectors, air quality standards (prohibition against open burning), and safety practices ensuring
protection from explosive gases, fires, and bird hazards to airports. Facilities that fail to comply with
any of these criteria are considered open dumps, which are prohibited by RCRA Section 4005. Those
facilities that meet the criteria are considered sanitary landfills under RCRA Section 4004(a).
3.1.2.2 40 CFR Part 258 Revised Criteria for Municipal Solid Waste Landfills
On October 9, 1991, EPA promulgated revised criteria for municipal solid waste landfills in
accordance with the authority provided in RCRA Sections 1008(a)(3), 4004(a), 4010 (c) and CWA
Sections 405(d) and (e) (see 56 FR 50978). Under the terms of these revised criteria, municipal solid
waste landfills are defined to mean a discrete area of land or an excavation that receives household
waste, and is not a land application unit, surface impoundment, injection well, or waste pile, as those
terms are defined in 40 CFR 257.2 and 258.2. In addition to household waste, a municipal solid
waste landfill unit also may receive other types of RCRA Subtitle D wastes, such as commercial solid
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waste, non-hazardous sludge, and industrial solid waste. Such a landfill may be publicly or privately
owned. A municipal solid waste landfill unit may be a new unit, existing municipal solid waste landfill
unit or a lateral expansion.
The municipal solid waste landfill revised criteria include location standards (Subpart B), operating
criteria (Subpart C), design criteria (Subpart D), groundwater monitoring and corrective action
(Subpart E), closure and post-closure care criteria (Subpart F), and financial assurance requirements
(Subpart G). The design criteria provide that new municipal solid waste landfill units and lateral
expansions of existing units (as defined in Section 258.2) must be constructed in accordance with
either: (1) a design approved by a Director of a State whose municipal solid waste landfill permit
program has been approved by EPA and which satisfies a performance standard to ensure that
unacceptable levels of certain chemicals do not migrate beyond a specified distance from the landfill
(Sections 258.40(a)(l), (c), (d), Table 1); or (2) a composite liner and a leachate collection system
(Sections 258.40(a)(2), (b)). The groundwater monitoring criteria generally require owners or
operators of municipal solid waste landfills to monitor groundwater for contaminants and generally
implement a corrective action remedy when monitoring indicates that a groundwater protection
standard has been exceeded. However, certain small municipal solid waste landfills located in arid
or remote locations are exempt from both design and groundwater monitoring requirements. The
closure standards require that a final cover be installed to minimize infiltration and erosion. The post-
closure provisions generally require, among other things, that groundwater monitoring continue and
that the leachate collection system be maintained and operated for 30 years after the municipal solid
waste landfill is closed. The Director of an approved State may increase or decrease the length of
the post-closure period.
Again, as is the case with solid waste disposal facilities that fail to meet the open dumping criteria hi
40 CFR Part 257, Subpart A, municipal solid waste landfills that fail to satisfy the revised criteria in
Part 258 constitute open dumps and are therefore prohibited by RCRA Section 4005 (40 CFR
258.1(h)). All solid waste disposal facilities (i.e., municipal solid waste landfills) that are subject to
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the requirements in the Part 258 revised criteria and that collect and discharge landfill-generated
waste waters are included in this category.
3.1.2.3 40 CFR Part 257, Subpart B Conditionally Exempt Small Quantity Generator
Revised Criteria
A conditionally exempt small quantity generator is generally defined as one who generates no more
than 100 kilograms of hazardous waste per month in a calendar year (40 CFR 261.5(a)). Such
conditionally exempt small quantity generators (with certain exceptions) are not subject to RCRA
Subtitle C requirements. However, on July 1, 1996, EPA: (1) amended Part 257 to establish criteria
that must be met by non-municipal, non-hazardous solid waste disposal units that receive
conditionally exempt small quantity generator waste; and (2) established separate management and
disposal standards (in 40 CFR 261.5(f)(3) and (g)(3) ) for those who generate conditionally exempt
small quantity generator waste (see 61 FR 342169). The conditionally exempt small quantity
generator revised criteria for such disposal units include location standards, groundwater monitoring,
and corrective action requirements.
3.1.3 Current Wastewater Regulations
Prior to this regulatory initiative, EPA has not promulgated national effluent guidelines for the
discharge of wastewaters from the landfills industry. In the absence of these guidelines, permit
writers have had to rely on a combination of their own best professional judgement (BPJ), water
quality standards, and technology transfer from other industrial guidelines in setting permit limitations
for direct discharges from landfills to surface waters. In addition, municipalities also have had to rely
on their own best professional judgement, pass-through analyses, and other local factors in
establishing pretreatment standards for the discharge of wastewaters to their municipal sewage
systems and POTWs.
In 1989, EPA completed a preliminary study of the Landfills industry. In a report entitled
"Preliminary Data Summary for the Hazardous Waste Treatment Industry," EPA concluded that
wastewater discharges from landfills can be a significant source of toxic pollutants being discharged
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to surface waters and POTWs. In a consent decree between NRDC and EPA, dated January 31,
1992, it was agreed that EPA would propose effluent limitations guidelines for the landfills point
source category.
3.2 Industry Profile
The growth of the Landfills industry is a direct result of RCRA and subsequent EPA and State
regulations that establish the conditions under which solid waste may be disposed. The adoption of
increased control measures required by RCRA has had a number of ancillary effects.
The RCRA requirements have affected the Landfills industry in different ways. On the one hand, it
has forced many landfills to close because they lacked adequate on-site controls to protect against
migration of hazardous constituents in the landfill, and it was not economical to upgrade the landfill
facility. As a result, a large number of landfills, especially facilities serving small populations, have
closed rather than incur me significant expense of upgrading.
Conversely, large landfill operations have taken advantage of economies of scale to serve wide
geographic areas and accept an increasing portion of the nation's solid waste. For example,
responses to the EPA's Waste Treatment Industry Survey indicated that 75 percent of the nation's
municipal solid waste was deposited in large landfills representing only 25 percent of the landfill
population.
EPA has identified several trends hi the waste disposal industry that may increase the quantity of
leachate produced by landfills. More stringent RCRA regulation and the restrictions on the
management of wastes have increased the amount of waste disposed at landfills with leachate
collection systems as well as the number of facilities choosing to send their solid wastes off-site to
commercial facilities in lieu of pursuing on-site management options. As a result of the 'increased
disposal of solid wastes in landfills, the amount of leachate generated, collected, and discharged will
increase, thus potentially putting at risk the integrity of the nation's waters.
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3.2.1 Industry Population
The initial landfill population studied as part of EPA's survey of the industry was defined by a mailing
list database developed by EPA from various sources such as State environmental and solid waste
departments, the National Survey of Hazardous Waste Treatment, Storage, Disposal, and Recycling
Facilities respondent list, Environmental Ltd.'s 1991 Directory of Industrial and Hazardous Waste
Management Firms, and other sources discussed in Chapter 4. A total of 10,477 landfills (plus one
pre-test facility) were identified as the initial landfill population in the United States in 1992,
representing 9,882 Subtitle D non-hazardous landfills and 595 Subtitle C hazardous landfills,
presented in Table 3-1 by state. A sampling of this initial population was solicited for technical
information via screener surveys, and a. sampling of the screener survey respondents were sent
Detailed Questionnaires. A total of 252 landfill facilities received Detailed Questionnaires and 220
facilities responded with sufficient technical data to be included in the questionnaire database. A
detailed discussion of screener survey and Detailed Questionnaire strata is presented in Chapter 4,
Section 4.3.
Because Detailed Questionnaires were only sent to a sampling of the initial industry population, the
information provided by questionnaire respondents needed to be scaled up to represent the entire
Landfills industry. National estimates were calculated by matching up the screener survey stratum
with the Detailed Questionnaire stratum. A weighting factor was calculated for each questionnaire
respondent and any data provided by the respondent was scaled up by this factor. Therefore, all data
presented throughout this chapter as national estimates are based on a combination of the Detailed
Questionnaire respondents' data scaled up by their individual weighting factors. Figure,3-1 presents
the logic used for the development of the national estimates. The methodology for calculating
national estimates is presented in the Statistical Development Document for the Landfills industry.
3.2.2 Number and Location of Facilities
Many of the landfill facilities presented in Table 3-1 do not generate and/or collect wastewaters within
the scope of this regulation. Landfill generated wastewaters evaluated for regulation in this guideline
3-11
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include leachate, gas collection condensate, track/equipment washwater, drained free liquids,
laboratory-derived wastewater, floor washings, recovering pumping wells, and contaminated storm
water. Contaminated groundwater and non-contaminated storm water are not proposed to be subject
to the proposed regulation.
National estimates of the Landfills industry indicate that only 1,662 of the total population of landfill
facilities collect in-scope wastewaters. EPA's survey of the industry was limited to those facilities
that collect in-scope landfill generated wastewaters, or about 16 percent of the total number of
landfills located in the U.S. Table 3-2 presents these Subtitle D and Subtitle C landfills that collect
in-scope wastewater by ownership type. The national estimates for the industry indicate that
approximately 43 percent of these landfills are municipally-owned facilities, 41 percent are
commercially-owned, and 13 percent are non-commercial captives. Table 3-2 also shows that the
majority of non-hazardous landfills are municipally- or commercially-owned facilities whereas
hazardous landfills are primarily commercially-owned and captive facilities.
3.2.2.1 Captive Landfill Facilities
Based on EPA's survey of the Landfills industry for this guideline, over 200 captive and intra-
company facilities with on-site landfills were identified. EPA has decided not to include within the
scope of the guideline landfill facilities operated in conjunction with other industrial or commercial
operations which only receive waste from off-site facilities under the same corporate structure (intra-
company facility) and/or receive waste generated on-site (captive facility) so long as the wastewater
is commingled for treatment with other process wastewaters.
A majority of these landfills were found at industrial facilities that are or will be subject to three
effluent guidelines: Pulp and Paper (40 CFR Part 430), Centralized Waste Treatment (proposed 40
CFR Part 437, 60 FR 5464 January 27,1995), or Organic Chemicals, Plastics and Synthetic Fibers
(40 CFR Part 414). In addition, EPA identified approximately 30 landfills subject to one or more of
the following categories: Nonferrous Metals Manufacturing (40 CFR Part 421), Petroleum Refining
(40 CFR 419), Timber Products Processing (40 CFR Part 429), Iron and Steel Manufacturing (40
3-12
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CFR Part 420), Transportation Equipment Cleaning (new category to be proposed in 1998), and
Pesticide Manufacturing (40 CFR Part 455).
Industry supplied data estimates that there are over 118 Pulp and Paper facilities with on-site landfills
and that over 90 percent commingle landfill leachate with process wastewater for treatment on-site.
The wastewater flow originating from landfills typically represents less than one percent of the total
flow through the facilities' wastewater treatment plant and in no case exceeds three percent of the
treated flow. Approximately six percent of pulp and paper mills send landfill generated wastewater
to a POTW along with process wastewater.
Based on responses to the 1992 Waste Treatment Industry: Landfills Questionnaire, EPA estimates
that there are more than 30 facilities subject to the Organic Chemicals, Plastics and Synthetic Fibers
(OCPSF) guideline with on-site landfills. At OCPSF facilities with on-site landfills, landfill leachate
typically represents less than one percent of the industrial flow at the facility, in no case exceeds six
percent of the flow, and is typically commingled with process wastewater for treatment.
3.2.3 General Information on Landfill Facilities
Landfill facilities located throughout the U.S. are estimated to cover approximately 726,000 acres of
land area, 20 percent of which is used as actual disposal area (landfill), 3 percent is used for
wastewater treatment operations, and 63 percent is undeveloped land. Table 3-3 presents national
estimates of the total landfill area covered by non-hazardous and hazardous landfill facilities. National
estimates indicate that hazardous facilities use less of their total facility area for waste disposal, only
about 5 percent, compared to non-hazardous facilities which use approximately 30 percent of their
total facility area for waste disposal. Table 3-4 presents facility land area ranges for non-hazardous
and hazardous facilities as well as totals for the industry. These frequency distributions show that a
typical facility is 100 to 1,000 acres in size, and the landfill covers between 10 and 100 acres of that
area. The majority of non-hazardous and hazardous landfill facilities have from 10 acres to 1,000
acres of undeveloped land available; larger facilities may have as much as 1,000 to 10,000 acres of
undeveloped land.
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Landfills are made up of individual cells which may be dedicated to one type of waste or may accept
many different types of waste. When a landfill cell reaches capacity volume, it is closed and is
referred to as an "inactive" cell. Landfill cells that are not at capacity and continue to accept waste
are considered to be "active" cells. Table 3-5 presents national estimates of the number of landfill
cells, both active and inactive, at non-hazardous and hazardous landfills. National estimates of landfill
facilities in the U.S. indicate that the average number of cells in a landfill is approximately six, with
facilities averaging anywhere from 2.75 active cells to six inactive cells. For hazardous facilities, most
landfills average 7.6 cells, with 4.2 active cells and 8.2 inactive cells. For non-hazardous facilities,
landfills average 5.7 cells with 2.5 active cells and 5.4 inactive cells. The number of survey
respondents was lower for "active" cells compared to "inactive" cells because these facilities reflect
the number of landfills in the U.S. that are presently open or active. There are fewer active landfills
in the U.S. than inactive, or closed landfills.
The number and type of customers served helps to define the size of a landfill. Table 3-6 presents
the national estimates of the household and non-household population served by landfills that collect
in-scope landfill wastewaters. The total population served by the Landfills industry is 46.3 million
household and 5.2 million non-household customers. Non-hazardous landfills serve 99 percent of
these customers. Hazardous landfills account for only 307,000 household customers and 170,000
non-household customers. Table 3-7 presents the frequency distributions of the number of household
and non-household customers for the non-hazardous and hazardous subcategories as well as for both
subcategories combined. Most non-hazardous facilities serve between 100 and 1,000 non-household
customers and 10,000 to 100,000 household customers. Hazardous facilities serve all ranges of non-
household customers, from zero to 10,000, but serve very few household customers.
3.2.4 Waste Receipts and Types
Wastes received by landfills in the United States vary from municipal solid waste to highly toxic
materials. Table 3-8 presents the national estimates of the types of waste received at landfills and the
percentage each waste represents of the total waste received during the following three periods: pre-
1980; 1980-1985; and 1986-1992. The primary waste types landfilled during the pre-1980 time
3-14
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period were municipal solid waste and industrial wastes, making up 61 percent of the waste, and
commercial solid waste and construction and demolition debris making up 17 percent of the waste.
Similar lypes of waste were landfilled after 1980; however, the percentage of municipal solid waste
and industrial waste decreased, and the amount of commercial solid waste, incinerator residues,
PCB/TSCA wastes, and asbestos-containing wastes increased. The landfilling of "other" waste types
which include contaminated soils, auto shredder scrap, and tires, also increased after 1980.
Table 3-9 presents the national estimates of wastes received by the Landfills industry in 1992 by
regulatory classification. These data indicate that landfills contained approximately 6.1 billion tons
of waste in 1992, and project a future capacity of 8.3 billion tons. However, the estimated future
capacity of Subtitle D landfills is much larger than the future capacity of Subtitle C landfills. On
average, Subtitle D landfills represent almost 75 percent of the future capacity of U.S. landfills.
Table 3-10 presents the national estimates of the annual tonnage of waste accepted by landfills from
1988 through 1992. In 1988, the annual tonnage of waste accepted by Subtitle C and Subtitle D
landfills was 221 million tons and by 1992, the amount of waste accepted annually increased by 94
million tons. The annual tonnage of waste accepted by the industry increased 17 percent from 1989
to 1990, and 12 percent from 1990 to 1991. However, Subtitle C landfills experienced the greatest
increase and in annual waste accepted from 1989 to 1991; in 1990 the amount of waste increased 23
percent from 1989, and in 1991 the amount of waste increased 43 percent from 1990. Over the three
year period,from 1989 to 1991, the annual tonnage of waste landfilled in Subtitle C landfills increased
56 percent. Conversely, the annual tonnage of waste accepted by Subtitle D landfills increased by
only 4 percent from 1990 to 1991 and 1991 to 1992, down from a 15 percent increase in 1990. This
increase in annual waste deposited in Subtitle C landfills may reflect the more strict enforcement of
RCRA regulations regarding what types of waste can be deposited in a Subtitle D landfill (Subtitle
C hazardous waste is now restricted from Subtitle D landfills and is disposed in Subtitle C landfills).
3-15
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3.2.5 Sources of Wastewater
As noted earlier, wastewater is generated from a number of landfill operations. In general, the types
of wastewater generated by activities associated with landfills and collected for treatment, discharge,
or recycled back to the landfill are leachate, landfill gas condensate, truck/equipment washwater,
drained free liquids, laboratory-derived wastewater, floor washings, recovering pumping wells,
contaminated groundwater, and storm water. Table 3-11 presents the national estimates of the
number of landfills that generate each type of wastewater and the minimum, maximum, and mean
flows. Each of these wastewater sources are discussed below.
3.2.5.1
Landfill Leachate
Landfill leachate is a liquid that has passed through or emerged from solid waste and contains soluble,
suspended, or miscible materials removed from such waste (40 CFR 258.2). Leachate typically is
collected from a liner system above which waste is placed for disposal. Leachate also may be
collected through the use of slurry walls, trenches or other containment systems. The leachate
generated varies from site-to-site, based on a number of characteristics which include the types of
waste accepted, operating practices including shedding, daily cover and capping, the depth of fill,
compaction of wastes, and landfill age. Based on EPA's survey of the industry, a total of 1,989
landfill facilities generate wastewater at flows ranging from one gallon per day to 533,000 gallons per
day, with a daily mean of approximately 13,600 gallons. Landfill leachate accounts for over 95
percent of in-scope wastewaters in the Landfills industry.
O.u.u.u
Landfill Gas Condensate
Landfill gas condensate is a liquid that has condensed in the landfill gas collection system during the
extraction of gas from within the landfill. Gases such as methane and carbon dioxide are generated
due to microbial activity within the landfill and must be removed to avoid hazardous conditions. In
the gas collection systems, gases containing high concentrations of water vapor condense in traps
staged throughout the gas collection network. The gas collection condensate contains volatile
compounds and typically accounts for a small portion of flow from a landfill. The national estimates
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presented on Table 3-11 report a total of 158 landfill facilities that generate landfill gas condensate
at daily flows ranging from 3 gallons to 11,700 gallons. The mean flow of landfill gas condensate for
the Landfills industry is approximately 510 gallons per day.
3.2.5.3
Truck and Equipment Washwater
Truck and equipment washwater is generated during either truck or equipment washes at landfills.
During routine maintenance or repair operations, trucks and/or equipment used within the landfill
(e.g., loaders, compactors, or dump trucks) are washed, and the resultant washwaters are collected
for treatment. In addition, it is common practice in hazardous landfills to wash the wheels, body, and
undercarriage of trucks used to deliver the waste to the open landfill face upon leaving the landfill.
On-site wastewater treatment equipment and storage tanks also are periodically cleaned with their
washwaters collected. It is estimated that 416 landfill facilities generate truck and equipment
washwater at a mean flow of 786 gallons per day and at daily flows ranging from 5 gallons per day
to 15,000 gallons per day.
Floor washings are also generated during routine cleaning and maintenance of landfill facilities.
National estimates presented on Table 3-11 indicate there are 70 landfill facilities that generate and
collect floor washings at flows ranging from 10 gallons per day to 5,450 gallons per day. The mean
flow of floor washings for the Landfills industry is approximately 1,760 gallons per day.
3.2.5.4 Drained Free Liquids
Drained free liquids are aqueous wastes drained from waste containers (e.g., drums, trucks, etc.) or
wastewater resulting from waste stabilization prior to landfilling. Landfills that accept containerized
waste may generate this type of wastewater. Wastewaters generated from these waste processing
activities are collected and usually combined with other landfill generated wastewaters for treatment.
National estimates presented on Table 3-11 identify 33 landfill facilities that generate drained free
liquids at a mean daily flow of 12,400 gallons. Daily flows range from a minimum of one gallon per
day to a maximum of 82,000 gallons per day.
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3.2.5.5 Laboratory-Derived Wastewater
Laboratory-derived wastewater is generated from on-site laboratories that characterize incoming
waste streams and monitor on-site treatment performance. This source of wastewater is minimal and
is usually combined with leachate and other wastewaters prior to treatment at the wastewater
treatment plant.
3.2.5.6 Recovering Pumping Wells
In addition to the contaminated groundwater generated during groundwater pumping operations,
there are various ancillary operations that also generate a wastewater stream. These operations
include construction and development, well maintenance, and well sampling (i.e. purge water). These
wastewaters will have very similar characteristics to the contaminated groundwater. EPA's survey
of the Landfills industry identified 50 landfill facilities that generate wastewater from recovering
pumping wells. Daily flows range from a minimum of 0.3 gallons to a maximum 80,167 gallons and
a mean daily flow of 16,900 gallons.
3.2.5.7
Contaminated Groundwater
Contaminated groundwater is water below the land surface in the zone of saturation that has been
contaminated by landfill leachate. Contamination of groundwater may occur at landfills without
liners or at facilities that have released contaminants from a liner system into the surrounding
groundwater and is collected and treated by landfills. Groundwater also can infiltrate the landfill or
the leachate collection system if the water table is high enough to penetrate the landfill area. EPA
identified approximately 163 landfill facilities that generate contaminated groundwater. Daily flows
ranged from 6 gallons per day to 987,000 gallons per day, with a mean daily flow of approximately
48,000 gallons. Contaminated groundwater has been excluded from regulation under this guideline
as discussed in Chapter 2 of this document.
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3.2.5.8
Storm Water
There are two types of storm water, contaminated and non-contaminated. Contaminated storm water
is runoff that comes in direct contact with the solid waste, waste handling and treatment areas, or
wastewater flows that are covered under this rule. Non-contaminated (non-contact) storm water
does not come in direct contact with solid waste, waste handling and treatment areas, or wastewater
flows which are covered under this rule. National estimates indicate that there are 1,135 landfill
facilities that generate storm water at flows ranging from 10 gallons per day to 2 million gallons per
day, with a mean daily flow of approximately 66,200 gallons. Storm water that does not come into
contact with the wastes would not be subject to the proposed limitations and standards.
3.2.6 Leachate Collection Systems
All facilities included in EPA's survey of the Landfills industry generate and collect landfill leachate.
To prevent waste material, products of waste decomposition, and free moisture from traveling beyond
the limits of the disposal site, landfill facilities utilize some type of leachate collection system. The
purpose of the leachate collection system is to collect leachate for treatment or alternate disposal and
to reduce the depths of leachate buildup or level of saturation over the liner.
The leachate collection system usually contains several individual components. Two main leachate
collection systems may be necessary: an underdrain system and a peripheral system. The underdrain
system is constructed prior to landfilling and consists of a drainage system that removes the leachate
from the base of the fill. The peripheral system can be installed after landfilling has occurred and,
as such, is commonly used as a remedial method. The underdrain system includes a drainage layer
of high permeability granular material, drainage tiles to collect the diverted flow laterally toward
them, and a low permeability liner underlying the system to retard the leachate that percolates
vertically through the unsaturated zone of refuse. Where the leachate meets the low permeability
layer, saturated depths of leachate develop and leachate flow is governed by hydraulic gradients
within the drainage layer (see reference 8).
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There are several different types of leachate collection systems employed by the Landfills industry to
collect the wastewaters generated by landfill operations. Table 3-12 presents the different types of
leachate collections systems and the national estimates of the number of facilities which employ each
system. A simple gravity flow drain field is the most basic and commonly used type of collection
system employed by 50 percent of the industry. Compound leachate collection systems, which are
comprised of a liner system and collection pipes, were used by 20 percent of the industry and trench
drains, which are gravel channels used to facilitate leachate drainage, were used by 15 percent of
landfill facilities in the U.S. Other types of leachate collection systems utilized by 10 percent of the
Landfills industry include collection sumps and risers, combined gas/leachate extraction wells,
perforated toe drains to pump stations, and gravity flow in pipes to a holding pond, basin, or pump
station to storage tanks.
3.2.7 Pretreatment Methods
Several types of waste accepted by landfills for disposal may require some type of pretreatment
Wastes that may require pretreatment include free liquids, containerized waste, and bulk wastes. Free
liquids may be drained or removed, or stabilized. Containerized waste and bulk wastes may be
shredded, stabilized, or solidified. Table 3-13 presents the types of pretreatment methods currently
in use by the Landfills industry and national estimates of the number of facilities that pretreat these
wastes.
Approximately 75 percent of non-hazardous landfill facilities do not accept free liquids, and of those
that do, 20 percent do not pretreat the liquids before treatment at an on-site wastewater treatment
facility or treatment off-site. In comparison, approximately 65 percent of hazardous landfill facilities
accept free liquids and pretreat by stabilizing, draining or removing the liquid. Containerized waste
is accepted by only 40 percent of non-hazardous landfill facilities, but is accepted by almost 75
percent of hazardous landfill facilities. The most common type of pretreatment for containerized
waste is solidification followed by stabilization. Bulk wastes are accepted by most landfills, although
many facilities do not pretreat this type of waste. Bulk wastes are usually treated by stabilization or
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solidification and stabilization; however, other types of pretreatment include compaction, chemical
treatment, flocculation, macro/microencapsulation, and recycling.
3.2.8 Baseline Treatment
Many landfills in the United States currently have wastewater treatment systems in place. The most
common treatment system used by landfills is biological treatment. However, chemical precipitation
and combinations of biological treatment, chemical precipitation, equalization, and filtration also are
used widely. Table 3-14, as well as Table 8-1, presents the types of treatment and the national
estimates of the number of facilities that employ each type of wastewater treatment. As expected,
indirect and zero dischargers often do not employ on-site treatment because they either ship their
waste waters off-site or use alternate disposal methods such as deep well injection, incineration,
evaporation, land application, or recirculation. A detailed discussion of treatment technology and
performance is presented in Chapter 8.
EPA's survey of the Landfills industry solicited wastewater treatment facility operating information
from non-hazardous and hazardous landfills. Table 3-15 presents the national estimates of the
number of landfill facilities that operate wastewater treatment systems between 1 and 24 hours per
day. Direct and zero or alternative discharge facilities tend to operate treatment systems
continuously, whereas many indirect discharge facilities operate less than 24 hours per day. Table
3-16 presents the average daily hours of operation of a typical on-site wastewater treatment facility.
Table 3-17 presents the national estimates of the number of landfill facilities that operate wastewater
treatment systems between 1 and 7 days per week. Again, direct and zero or alternative discharge
facilities commonly operate their treatment systems continuously, whereas indirect dischargers do not.
Table 3-18 presents the average number of days per week a typical wastewater treatment facility is
in operation.
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3.2.9 Discharge Types
Landfill facilities surveyed by the EPA are often grouped by discharge types. Direct dischar^
facilities are those that discharge their waste-waters directly to a receiving stream or body of water.
Indirect discharging facilities discharge their wastewater indirectly to a POTW. Zero or alternative
discharge facilities use treatment and disposal practices that result in no discharge of wastewater to
surface waters. Zero or alternative disposal options for landfill generated wastewater include off-site
treatment at another landfill wastewater treatment system or a Centralized Waste Treatment facility,
deep well injection, incineration, evaporation, land application, solidification, and recirculation.
Table 3-19 presents the national estimates of the number of landfill facilities grouped by discharge
type. These estimates show that the majority of non-hazardous facilities-included in the survey were
indirect dischargers, whereas the majority of hazardous facilities were mainly direct and zero
dischargers.
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Table 3-1: Number of Landfills per U.S. State
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
Guam
Total
Subtitle D
Landfills
238
201
90
134
630
216
125
8
91
277
15
112
182
101
118
118
121
73
291
50
722
762
257
97
128
257
41
127
58
467
121
565
244
85
119
189
231
41
12
127
193
112
601
92
73
440
72
57
183
218
0
0
9,882
Subtitle C
Landfills
38
1
2
3
16
12
22
14
9
17
1
6
14
29
13
8
33
17
2
5
1
9
4
3
7
1
8
3
0
8
7
10
39
1
24
7
10
22
0
9
o -
9
70
7
0
8
9
5
3
45
3
1
595
Total
Landfills
276
202
92
137
646
228
147
22
100
294
16
118
196
130
131
126
154
90
293
55
723
771
261
100
135
258
49
130
58
475
128
575
283
86
143
196
241
63
12
136
193
121
671
99
73
448
81
62
186
263
3
1
10.477
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Table 3-2: Ownership Status of Landfill Facilities
Ownership Status
Commercial
Non-Commercial (intra-company)
Non-Commercial (captive)
Municipal
Federal Government
Government (other than Federal or
Municipal)
Indian Tribal Interest
Other
Total
Number of Facilities
Subtitle D
Non-Hazardous
Subcategory
506
5
121
708
4
0
0
1
1,345
Subtitle C
Hazardous
Subcategory
171
48
94
2
2
0
0 .
0
317
Industry Total
677
53
215
710
6
0
0
1
1,662
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Table 3-3: Total Landfill Facility Area
Facility Land Type
Total Facility Area
Wastewater Treatment Area
Waste Disposal Area (landfill)
Undeveloped Land
Landfill Facility Area (acres)
Subtitle D
Non-Hazardous
Subcategory
416,733
9,424
119,700
254,610
Subtitle C
Hazardous
Subcategory
309,194
10,147
16,552
207,085
Industry Total
725,927
19,571
136,323
459,811
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Table 3-4: Landfill Facility Land Area Ranges
Subcategory
All Facilities
Land Area Range
(acres)
0
>0-1
>1-10
>10-100
>100-1,000
>1,000-10,000
Total
Subtitle C
Hazardous
Subtitle D
Non-Hazardous
0
>0-1
>1-10
>10-100
>100-1,000
>1,000-10,000
Total
0
>0-1
>1-10
>10-100
>100-1,000
>1,000-10,000
Total
Number of Landfill Facilities
Total Facility
Area
0
0
9
490
1,044
119
1,662
0
0
2
95
136
84
317
0
0
7
395
909
34
1,345
Wastewater
Treatment
Area
747
320
437
136
22
0
1,662
38
128
70
65
15
0
316
708
191
366
72
7
0
1,344
Waste
Disposal Area
(landfill)
28
16
126
1,128
362
0
1,660
5 ,
14
47
199
52
0
317
23
2
79
930
310
0
1,344
Undeveloped
Land
110
2
69
561
745
85
1,662
49
0
2
99
106
60
316
61
2
67
551
638
25
1,344
3-26
-------
Table 3-5: Number of Landfill Cells
Subcategory
All Facilities
Subtitle C
Hazardous
Subtitle D
Non-Hazardous
Type of Landfill Cell
Total cells
Active cells
Inactive cells
Total cells
Active cells
Inactive cells
Total cells
Active cells
Inactive cells
Number of Cells
Estimated Mean
6.12
2.75
6.05
7.64
.4.23
8.24
5.68
2.48
5.41
Estimated Total
13,299
4,608
8,690
3,776
1,112
2,663
9,523
3,496
6,027
3-27
-------
Table 3-6: Household and Non-Household Population Served
Population Served
Non-Household
Household
Number of Customers
Subtitle D
Non-Hazardous
Subcategory
5,043,542
46,007,775
Subtitle C
Hazardous
Subcategory
170,420
307,243
Industry Total
5,213,962
46,315,018
3-28
-------
Table 3-7: Household vs. Non-Household Customers
Number of Non-Household Customers
0
1
>1-10
>10-100
> 100- 1,000
>1,000-10,000
>10,000-100,000
>100,000-1,00,000
Total
Number of Household Customers
0
1
>1-10
>10-100
>100-1,000
>1,000-10,000
>10,000-100,000
>100,000-1,00,000
Total
Number of Facilities
Subtitle D
Non-Hazardous
Subcategory
76
83
33
202
544
351
55
2
1,346
180
0
55 '
29
42
195
742
102
1,345
Subtitle C
Hazardous
Subcategory
123
40
12
4
87
51
0
0
317
313
0
0
0
0
2
0
2
317
Industry Total
205
124
45
203
628
400
54
2
1,661
506
0
55
28
42
195
733
103
1,662
3-29
-------
Table 3-8: Wastes Received by Landfills in the United States
Waste Type
Municipal Solid Waste
Household Hazardous Waste
Yard Waste
Commercial Solid Waste
Institutional Wastes
Industrial Wastes
Agricultural Waste
Pesticides
PCB, TSCA Wastes
Asbestos-Containing Waste
Radioactive Waste
Medical or Pathogenic Waste
Superfund Clean-Up Wastes
Mining Wastes
Incinerator Residues
Fly Ash, Not Incinerator Waste
Construction/Demoh'tion Debris
Sewage Sludge
Dioxin Waste
Other Sludge
Other Waste Types
Industry Total
Mean % for
Time Period
Pre-1980
38.3
0.217
4.76
8.56
1.36
22.8
0.340
0.033
0.192
0.905
0.019
0.255
0.000
0.519
1.01
4.49
8.40
1.81
0.000
4.89
1.23
100.09
Mean % for
Time Period
1980-85
33.4
0.218
4.39
9.92
1.43
19.6
0.297
0.009
1.12
3.73
0.002
0.182
0.021
0.47
1.43
5.82
5.91
3.15
0.039
4.90
4.49
100.528
Mean % for
Time Period
1986-92
33.9
0.215
3.76
9.94
2.14
17.4
0.284
0.321
0.980
3.42
0.001
0.123
0.014
0.180
3.14
6.30
7.95
2.88
0.024
2.91
5.25
101.132
3-30
-------
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3-31
-------
Table 3-10: Annual Tonnage of Waste Accepted by Landfills
Year
1988
1989
1990
1991
1992
Annual Tonnage of Waste (tons)
Subtitle D
Non-Hazardous
Subcategory
185,184,608
196,377,576
232,535,432
241,454,300
252,101,069
Subtitle C
Hazardous
Subcategory
36,305,235
28,867,681
37,413,692
65,402,768
63,022,850
Industry Total
221,489,843
225,245,257
269,949,125
306,857,068
315,123,919
3-32
-------
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3-33
-------
Table 3-12: Type of Leachate Collection Systems Used at Individual Landfills
Type of Leachate
Collection
None
Simple Gravity Flow
Drain Field
French Drain System
Compound Leachate
Collection
Suction Lysimeters
Other
Total
Number of Landfills
Subtitle D
Non-Hazardous
Subcategory
46
977
341
416
196
1,976
Subtitle C Hazardous
Subcategory
87
266
38
93
2
49
535
Industry Total
132
1,242
379
509
2
246
2,510
3-34
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Table 3-13: Pretreatment Methods in Use at Individual Landfills
Type of Waste
Free Liquids
Containerized
Waste
Bulk Wastes
Pretreatment Method
No Pretreatment
None Accepted
Drained or Removed
Stabilization
Other
Total
No Pretreatment
None Accepted
Shredded
Stabilized
Solidified
Other
Total
No Pretreatment
None Accepted
Baled
Shredded
Stabilized
Solidified
Other
Total
Number of Landfills
Subtitle D
Non-
Hazardous
Subcategory
324
1,277
51
38
17
1,707
515
1,008
23
6
41
110
1,703
993
414
33
82
15
74
100
1,711
Subtitle C
Hazardous
Subcategory
113
283
115
172
84
767
100
180
70
135
138
80
703
216
61
2
49
201
126
38
693
Industry Total
437
1,560
166
211
101
2,475
616
1,188
94
141
179
190
2,408
1,209
475
35
131
216
200
138
2,404
3-35
-------
Table 3-14: Types of Wastewater Treatment Employed by the Landfills Industry
Type of Treatment
No treatment
Biological treatment
Chemical precipitation
Cherncial precipitation and biological
treatment
Filtration and biological treatment
Equalization and biological treatment
Equalization, biological treatment, and
filtration
Equalization, chemcial precipitation, and
biological treatment
Equalization, chemcial precipitation,
biological treatment, and filtration
Number of Landfills
Direct
Discharge
84
119
63
32
45
65
37
26
26
Indirect
Discharge
689
37
45
10
4
28
4
8
2
Zero
Discharge
468
19
8
0
5
7
5
0
0
3-36
-------
3
O
H
1
a
i — i
OKI C*
3 0
JQ r^3 o
& CS X>
&o EH 2
00
Subtitle D
Mon-Hazardouj
Subcategory
o
ISI
•*-»
i
H- (
-------
Table 3-16: Wastewater Treatment Facility Average Hours of Operation per Day
Subcategory
All Facilities
Subtitle C
Hazardous
Subtitle D
Non-Hazardous
Average Hours of Operation/Day
Direct Discharge
22.81
22.78
22.86
Indirect Discharge
19.10
22.18
18.42
Zero Discharge
22.55
23.46
21.89
3-38
-------
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r-
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Subtitle D
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Subcategory
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3-39
-------
Table 3-18: Wastewater Treatment Facility Average Days of Operation per Week
Subcategory
All Facilities
Subtitle C
Hazardous
Subtitle D
Non-Hazardous
Average Days of Operation/Week
Direct Discharge
6.73
6.56
6.94
Indirect Discharge
6.46
6.83
6.38
Zero Discharge
6.81
6.77
6.84
3-40
-------
Table 3-19: Total Number of Facilities by Discharge Type
Subcategory
All Facilities
Subtitle C
Hazardous
Subtitle D
Non-Hazardous
Discharge Type
Direct
310
134
176
Indirect
823
24
799
Zero
529
159
370
Total
1,662
317
1,345
3-41
-------
Figure 3-1: Development of National Estimates for the Landfills Industry
§
'3
I
&
"3
•S3
a
Collected data on landfill facilities from various sources and
developed initial landfill population
10,477 landfill facilities identified
9,882 Subtitle D non-hazardous landill facilities
595 Subtitle C hazardous landfill facilities
fr
to
I
to
4,996 landfill facilities were selected to
receive screener surveys
3,682 landfill facilities responded to the
screener survey.
Of the 3,682 respondents, 859 were considered
in-scope (i.e., generating some type of landfill
generated wastewater)
252 landfill facilities were selected to receive
Detailed Questionnaire
220 landfill facilities responded to the Detailed
Questionnaire with suffient technical detail to
be included in database
156 Subtitle D non-hazardous landfill facilities
20 Subtitle C hazardous landfill facilities
44 facilities are excluded from regulation
27 landfill facilities were
. selected to complete a
Detailed Monitoring
Questionnaire
1
•a
C
National estimates were calculated based upon assigning a
weighting factor for each facility in the Detailed Questionnaire
database
1,662 total landfill facilities which generate in-scope wastewater
based on national estimates:
1,345 Subtitle D non-hazardous landill facilities
317 Subtitle C hazardous landfill facilities
3-42
-------
4.0 DATA COLLECTION ACTIVITIES
4.1 Introduction
As part of the Landfills industry study, EPA collected data from a variety of different sources. These
sources included existing data from previous EPA and other governmental data collection efforts,
industry provided information, new data collected from questionnaire surveys, and field sampling
data. Each of these data sources is discussed below, as well as the quality assurance/quality control
(QA/QC) and other data editing procedures. Summaries and analyses of the data collected by EPA
are presented in Chapters 5 through 10.
4.2 Preliminary Data Summary
EPA's initial effort to develop effluent limitations guidelines and pretreatment standards for the waste
treatment industry began in 1986. EPA conducted a study of the hazardous waste treatment industry
in which it determined the scope of the industry, its operations, and types of discharges. In this study,
the hazardous waste treatment industry included landfills with leachate collection and treatment
facilities, incinerators with wet scrubbers, and aqueous hazardous waste treatment facilities. This
study characterized the wastewaters generated by facilities in the industry and the wastewater
treatment technologies used to treat these wastewaters. In addition, the study included industry
profiles, the cost of wastewater control and treatment, and environmental assessments. The results
of this study were published by EPA in a report entitled "Preliminary Data Summary for the
Hazardous Waste Treatment Industry" (EPA 440/1-89-100), in September, 1989.
The data presented hi this report were collected from the following sources:
EPA Office of Research and Development databases: includes field sampling efforts
at 13 hazardous waste landfills in 1985.
State Agencies: includes a Wisconsin sampling program of 20 municipal landfills in
1983.
4-1
-------
• EPA Office of Emergency and Remedial Response Contract Laboratory Program
(CLP) Statistical Database, "Most Commonly Occurring Analytes in 56 Leachate
Samples." 1980-83 data.
• National Enforcement Investigations Center (NEIC) sampling program conducted for
the Hazardous Waste Ground-water Task Force during 1985.
EPA sampling at 6 landfill facilities (1986-1987).
• Subtitle D leachate data for miscellaneous Subtitle D landfills, compiled by the EPA
Office of Solid Waste.
The EPA Preliminary Data Summary identified 911 landfills that generate leachate. Of these, 173
discharged their leachate directly to surface waters, and 355 discharged indirectly through publicly
owned treatment works (POTWs). The remaining 383 used other methods of leachate disposal. The
most common "other" disposal method was contract hauling to a commercial aqueous waste
treatment facility. However, some facilities land applied their leachate (spraying of the leachate over
the landfill) or injected it into a deep well for disposal.
The key findings of the EPA Preliminary Data Summary included:
• Some leachates were found to contain high concentrations (e.g., over 100,000
micrograms per liter (ug/1)) of toxic organic compounds.
• Raw leachates were found to contain high concentrations of BOD5, COD, and TOC.
• Leachate flow rates varied widely due to climatic and geological conditions and
landfill size. An average landfill was estimated to have a leachate generation rate of
approximately 30,000 gallons per day (gpd).
• Due to current RCRA regulations, the number of leachate collection systems used at
landfills was expected to increase.
• RCRA regulations also would cause solid waste generators to increase their use of
commercial landfill facilities.
4-2
-------
A wide range of biological and physical/chemical treatment technologies were found to be in use by
landfills, capable of removing high percentages of conventional, nonconventional, and toxic
pollutants. Advanced treatment technologies identified in this study include air stripping, ammonia
stripping, activated carbon, and lime precipitation.
After a thorough analysis of the landfill data presented in the Preliminary Data Summary, EPA
identified the need to develop an effluent guidelines regulation for the Landfills industry in order to
set national guidelines and standards. EPA's decision to develop effluent limitations guidelines was
based on the Preliminary Data Summary's assessment of 1he current and future trends in the Landfills
industry, its analysis of the concentrations of pollutants in the raw leachate, and the study's discussion
on the treatment and control technologies available for effective pollution reduction in landfill
leachate.
4.3 Clean Water Act Section 308 Questionnaires
A major source of information and data used in developing effluent limitations guidelines and
standards was industry responses to detailed technical and economic questionnaires, and the
subsequent detailed monitoring questionnaires, distributed by EPA under the authority of Section 308
of the Clean Water Act. These questionnaires requested information on each facility's industrial
operations, ownership status, solid wastes disposed, treatment processes employed, and wastewater
discharge characteristics. EPA first developed a database of various types of landfills in the United
States using information collected from: 1) State environmental and solid waste departments, 2) other
State agencies and contacts, 3) the National Survey of Hazardous Waste Treatment Storage, Disposal
and Recycling Facilities respondent list, 4) Environmental Ltd.'s 1991 Directory of Industrial and
Hazardous Waste Management Firms, 5) the Resource Conservation and Recovery Act (RCRA)
1992 list of Municipal Landfills, and 6) the Resource Conservation and Recovery Information System
(RCRIS) National Oversight Database. Based upon these sources, the initial population of 10,477
facilities in the landfill database was divided into two categories: 595 Subtitle C hazardous and 9,882
Subtitle D non-hazardous facilities.
4-3
-------
This database served as the initial population for EPA to collect industry provided data. EPA's data
collection process involved three stages:
Screener Surveys
• Detailed Technical Questionnaires
• Detailed Monitoring Questionnaires
Each of these data collection activities are discussed in the following sections. A more detailed
discussion of the landfills survey population can be found in Appendix A.
4.3.1 Screener Surveys
Once the database identifying the number of landfills in the U.S. was complete, EPA developed a
screener survey to collect initial data on all possible landfill sites in the U.S. and to update information
on ownership and facility contacts.
4.3.1.1 Recipient Selection and Mailing
The 10,478 facilities were divided into four strata for the purpose of determining the screener survey
recipients. These strata were defined as:
1. Subtitle C facilities.
2. Subtitle D facilities that are known wastewater generators.
3. Subtitle D facilities in states with no more than 100 landfills and are not known to be
wastewater generators.
4. Subtitle D facilities in states with more than 100 landfills and are not known to be
wastewater generators.
4-4
-------
All of the facilities in strata 1, 2, and 3 were selected to receive the screener survey. A random
sample of the facilities in stratum 4 were selected. Table 4-1 presents the sample frame, number of
facilities sampled, and the number of respondents to receive the screener survey.
Table 4-1: Screener Questionnaire Strata
Screener Stratum
(g)
1
2
3
4
Total
Number in Frame
w
595
134
892
8,856
10,477
Number Sampled
K)'
595
134
892
3,375
4,996
Number of Responses
fr'g)
524
120
722
2,621
3,987
4.3.1.2 Information Collected
Information collected by the screener surveys included:
• mailing address.
• landfill type, including types and amount of solid waste disposed and landfill capacity.
• wastewater generation rates as a result of landfill operations, including leachate, gas
condensate, and contaminated grouhdwater.
• regulatory classification and ownership status.
• wastewater discharge status.
• wastewater monitoring practices.
• wastewater treatment technology hi use.
4-5
-------
4.3.1.3 Data Entry, Coding, and Analysis
The EPA operated a toll-free help line to assist the screener recipients with filling out the 3-page
survey. The Agency responded to several thousand phone calls from facilities over a six week period.
The help line answered questions regarding applicability, EPA policy, and economic and technical
details.
All screener surveys returned to EPA were reviewed manually to verify that each respondent
completed the critical questions in the survey (e.g., wastewater generation and collection, number and
types of landfills, discharge status, and wastewater treatment technology). The screeners were in a
bubble-sheet format and were scanned directly into a computer database. • Once entered, the database
was checked for logical inconsistencies and follow up contacts were made to facilities to resolve any
inconsistencies.
After the QA process, facilities in the database were divided into two groups: 1) facilities that
indicated they collected landfill generated wastewaters; and 2) those that did not. Facilities that did
not collect landfill generated wastewaters were considered out of the scope of the Landfills industry
study and were not investigated further.
4.3.1.4
Mailout Results
Of the 4,996 screener questionnaires mailed by EPA, 3,628 responded, and of those, 3,581 were
eligible and complete and were entered into the screemer database. Of these, EPA identified 859
facilities that generate and collect one or more types of landfill generated wastewaters.
4-6
-------
4.3.2 Detailed Technical Questionnaires
Once the information from the screener surveys was entered into the database and analyzed, EPA
then developed a detailed technical and economic questionnaire to obtain more information from
facilities that collect landfill generated wastewater as indicated in their screener survey.
4.3.2.1
Recipient Selection and Mailing
The 859 facilities that were found to generate and collect landfill wastewater from the screener
database, plus one pre-test questionnaire facility that was not in the screener database, .were used as
the frame for selection of facilities to be sent a Detailed Questionnaire. These facilities were divided
into the following eight strata:
1.
3.
4.
5.
6.
7.
8.
Commercial private, municipal, or government facilities that have wastewater
treatment and are direct or indirect dischargers.
Commercial private, municipal, or government facilities that have wastewater
treatment and are not direct or indirect dischargers.
Non-commercial private facilities with wastewater treatment
Facilities with no wastewater treatment
Commercial facilities that accept PCB wastes
Municipal hazardous waste facilities
Small businesses with no wastewater treatment
Pre-test facilities that were not in the screener population
All facilities in strata 1,5,6,7, and 8 were selected to receive the Detailed Questionnaire. A random
sample of the facilities in strata 2, 3, and 4 were selected to receive the Detailed Questionnaire.
This selection criteria resulted in a mailing of the Detailed Questionnaire to 252 facilities. The
population analysis (referred to as national estimates) conducted on these questionnaire recipients is
4-7
-------
discussed briefly in Chapter 3 (Section 3.2.1) and in greater detail in the rulemaking record for this
proposed regulation under the topic "Statistical Analysis of Questionnaire Data".
4.3.2.2
Information Collected
The Detailed Questionnaire solicited technical and costing information regarding landfill operations
at the selected facilities and was divided into the following four sections:
• Section A - Facility Identification and Operational Information:
1. General facility information, including: ownership status, landfill type, the number of
landfills on site, regulatory status, discharge status, when the landfill began accepting
waste, and projected closure date.
2. Landfill operation, including: types of waste accepted at the landfill, the amount of
waste accepted, landfill capacity, how the waste was organized in the landfill, landfill
caps, and landfill liners.
3. Wastewater generation from landfill operations, including: the types of wastewater
generated and the generation rates, and the ultimate disposal of the wastewaters
generated and collected.
• Section B - Wastewater Treatment:
1. Description of treatment methods employed by the facility to treat the wastewaters
identified in Section A. This description includes a discussion of commingled
wastewaters, wastewater treatment technologies, residual waste disposal, and
treatment plant capacities.
• Section C - Wastewater Monitoring Data:
1. A summary of the monitoring data pertaining to the landfill generated wastewaters
identified in Section A that were collected in 1992 by the facility, including: minimum,
maximum, averages, number of observations, and sampling and analytical methods.
• Section D - Detailed Wastewater Treatment Design Information:
1. Detailed technical design, operation and costing information pertaining to the
wastewater treatment technologies identified in Section B.
4-8
-------
4.3.2.3
Data Entry, Coding, and Analysis
The EPA operated a toll-free help line to assist the questionnaire recipients with filling out the
Detailed Questionnaire. The EPA responded to over one thousand phone calls from facilities over
a three month period. While some calls pertained to questions of applicability, most were of a
technical nature regarding specific questions in the questionnaire.
Once the completed questionnaires were received by the EPA, each one was thoroughly reviewed
for technical accuracy and content. After the questionnaire was reviewed, it was coded for double-
key entry into the questionnaire database. All discrepancies between the two inputted values were
corrected by referring to the original questionnaire.
Several QA/QC procedures were implemented for the questionnaire database, including a manual
completeness and accuracy check of a random selection of 20 percent of the questionnaires and a
database logic check of each completed questionnaire. These QA/QC procedures helped verify the
questionnaires for completeness, resolve any internal consistencies, and identify outliers in the data
which were checked for accuracy.
4.3.2.4
Mailout Results
Of the 252 recipients, 220 responded with sufficient technical and economic data to be included hi
the final EPA Detailed Questionnaire database.
4.4 Detailed Monitoring Questionnaire
In addition to the Detailed Questionnaire, EPA also requested detailed wastewater monitoring
information from 27 facilities included in the Detailed Questionnaire database via a Detailed
Monitoring Questionnaire.
4-9
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4.4.1 Recipient Selection and Mailing
These facilities were selected based upon their responses to the Detailed Questionnaire. EPA
reviewed each facility's monitoring summary, discharge permit requirements, and their on-site
treatment technologies. From these responses, EPA selected 27 facilities to receive a Detailed
Monitoring Questionnaire which could provide useful information on technology performance,
pollutant removals, and wastewater characterization.
4.4.2 Information Collected
Facilities selected to receive the Detailed Monitoring Questionnaire were requested to send analytical
data (1992, 1993, and 1994 annual data) on daily equalized influent to their wastewater treatment
system, as well as effluent data from the treatment system. The three years of analytical data assisted
EPA in calculating the variability factors (Chapter 11) used in determining the industry effluent limits.
Analytical data for intermediate waste treatment points also were requested for some facilities. In
this manner, EPA was able to obtain performance information across individual treatment units in
addition to the entire treatment train.
4.4.3 Data Entry, Coding, and Analysis
EPA conducted a thorough review of each Detailed Monitoring Questionnaire response to ensure that
the data provided was representative of the facility's treatment system. EPA collected data from 24
semi-continuous and continuous treatment systems and 2 batch treatment systems. A Detailed
Monitoring Questionnaire database then was developed which included all monitoring data submitted
by the selected facilities.
4.5 Engineering Site Visits
EPA conducted engineering site visits at 19 facilities including one facility outside the U.S. The
purpose of these visits was to evaluate each facility as a potential week-long sampling candidate to
collect treatment performance data. The selection of these facilities was based on the responses to
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the Detailed Questionnaire and included facilities from as broad a cross section of the industry as
possible. EPA visited landfills of various ownership status (municipal, commercial, captive), landfills
that accept various waste types (construction and demolition, ash, sludge, industrial, municipal,
hazardous), and landfills in different geographic regions of the country. Facilities selected for
engineering site visits employed various types of treatment processes, including: equalization,
chemical and biological treatment, filtration, air stripping, steam stripping, and membrane separation.
Each landfill was visited for one day. During the engineering site visit, EPA obtained information on:
• the facility and its operations.
• the wastes accepted for treatment and the facility's acceptance criteria.
• the raw waste water generated and its sources.
• the wastewater treatment on site.
• the location of potential sampling points.
• the site-specific sampling needs, issues of access, and required sampling safety
equipment.
Table 4-2 presents a summary of the landfill facilities that were included in the engineering site visits.
4.6 Wastewater Characterization Site Visits
While conducting engineering site visits to landfill facilities, EPA also collected samples for raw
wastewater characterization at 15 landfills. EPA collected grab samples of untreated wastewater at
various types of landfills and analyzed for constituents in the wastewater including conventionals,
metals, organics, pesticides and herbicides, PCBs, and dioxins and furans. Chapter 6 presents the
characterization data obtained by EPA.
Table 4-2 also presents a summary of the landfill facilities by type that were included in the
characterization site visits and the number of wastewater characterization samples collected.
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4.7 EPA Week-Long Sampling Program
To collect wastewater treatment performance data, EPA conducted week-long sampling efforts at
six landfills. Selection of these facilities was based on Hie analysis of the information collected during
the engineering site visits. Table 4-3 presents a summary of the types of landfills sampled and
treatment technologies evaluated.
EPA prepared a detailed sampling plan for each sampling episode. Wastewater samples were
collected at influent, intermediate, and effluent sample points throughout the entire on-site wastewater
treatment system. Sampling at five of the facilities consisted of 24-hour composite samples for five
consecutive days. For the sixth facility, composites were taken of four completed batches over five
days. Individual grab samples were collected for oil and grease. Volatile organic grab samples were
composited in the laboratory prior to analysis.
Samples then were analyzed using EPA Office of Water approved analytical methods. The following
table presents the pollutant group and the analytical method used:
Pollutant Group
Conventional and Nonconventionals
Metals
Organics
Herbicides, Pesticides, PCBs
Dioxins/Furans
Analytical Method
Standard Methods
EPA 1620
EPA 1624, 1625
EPA 1656, 1657,1658
EPA 1613
Data resulting from the influent samples were used to characterize raw wastewater for the industry
and develop the list of pollutants of interest. The data collected from the influent, intermediate, and
effluent points were used to evaluate performance of the wastewater treatment systems, develop
current discharge concentrations, pollutant loadings, and the best available treatment (BAT) options
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for the Landfills industry. Data collected from the effluent points were used to calculate long term
averages for each of the proposed regulatory options.
4.8 Other Data Sources
In addition to the original data collected by EPA, other data sources were used to supplement the
industry database. Each of these data sources is discussed below.
4.8.1 Industry Supplied Data
The Landfills industry was requested to provide relevant information and data. Leachate and
groundwater characterization and treatabiliry studies were received from several facilities, including
25 discharge monitoring report (DMR) data packages. Industry supplied data was used to
characterize the industry, develop pollutant loadings, and develop effluent limitations.
4.8.2 Comprehensive Environmental Response, Compensation and Liability Act
(CERCLA)/Superfimd Amendments and Reauthorization Act (SARA) Groundwater
Data
Groundwater data was obtained from the "CERCLA Site Discharges To POTWs Treatabiliry
Manual" (EPA 540/2-90-007), prepared by the Industrial Technology Division of the EPA Office of
Water Standards and Regulations for the EPA Office of Emergency and Remedial Response. Data
from this study were used to supplement the groundwater data collected during characterization and
week-long sampling events. The purpose of the study was to:
Identify the variety of compounds and concentration ranges present in groundwater
at CERCLA sites.
Collect data on the treatability of compounds achieved by various on-site pretreatment
systems.
Evaluate the impact of CERCLA discharges to a receiving POTW.
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A total of eighteen CERCLA facilities were sampled in this study; however, only facilities that
received contaminated groundwater as a result of landfilling activities were selected to be used in
conjunction with the EPA groundwater sampling data. The data from seven CERCLA facilities were
combined with EPA sampling data to help characterize the hazardous subcategory and to develop
both the current discharge concentrations and pollutant loadings for facilities in the hazardous
subcategory.
4.8.3 POTW Study
EPA used the data included in the report entitled "Fate of Priority Pollutants in Publicly Owned
Treatment Works" (EPA 440/1-82-303), commonly referred to as the "50-POTW Study", in
determining those pollutants that would pass through a POTW. This study presents data on the
performance of 50 representative POTWs that generally achieve secondary treatment (30 mg/1 of
BOD5 and TSS). Additional work performed with this database included the revision of some data
editing criteria. Because the data collected for evaluating POTW removals included influent levels
of pollutants that were close to the detection limit, the POTW data were edited to eliminate low
influent concentration levels. The data editing rules for the 50-POTW study were as follows: 1)
detected pollutants must have at least 3 pairs (influent/effluent) of data points to be included, 2) for
analytes that included a combination of high and low influent concentrations, the data were edited to
eliminate all influent values, and corresponding effluent values, less than 10 times the minimum level,
i
3) for analytes where no influent concentrations were greater than 10 times the minimum level, all
influent values less than five times the minimum level and the corresponding effluent vailues were
eliminated, and 4) for analytes where no influent concentration was greater than five times the
minimum level, the data were edited to eliminate all influent concentrations, and corresponding
effluent values, less than 20 ug/1. The remaining averaged pollutant influent values and the
corresponding averaged effluent values then were used to calculate the average percent removal for
each pollutant when conducting the POTW pass-through analysis for this industry, which is discussed
in detail in Chapter 7.
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4.8.4 National Risk Management Research Laboratory Data
EPA's National Risk Management Research Laboratory (NRMRL) developed a treatability database
(formerly called the Risk Reduction Engineering laboratory (RREL) database). This computerized
database provides information, by pollutant, on removals obtained by various treatment technologies.
The database provides the user with the specific data source and the industry from which the
wastewater was generated. The NRMRL database was used when conducting the POTW pass-
through analysis by supplementing the treatment information provided in the 50-POTW study when
there was insufficient information on specific pollutants. For each of the pollutants of interest not
found in the 50-POTW database, data from portions of the NRMRL database were obtained. These
files were edited so that only treatment technologies representative of typical POTW secondary
treatment operations (e.g., activated sludge, activated sludge with filtration, aerobic lagoons) were
used. The files were further edited to include information pertaining to domestic or industrial
wastewater, unless only other wastewater data were available. Pilot-scale and full-scale data were
used; bench-scale data were eliminated. Data only from a paper hi a peer-reviewed journal or
government report were used; lesser quality references were edited out. Additionally, acceptable
references were reviewed and non-applicable study data were eliminated. From the remaining
pollutant removal data, the average percent removal for each pollutant was calculated. The pass-
through analysis conducted for this industry is discussed in detail in Chapter 7.
4.9 QA/QC and Other Data Editing Procedures
This section presents the quality assurance/quality control (QA/QC) procedures and editing rules used
to analyze the different analytical data sets that were described in the previous sections; including
industry supplied data, Detailed Questionnaire data; Detailed Monitoring Questionnaire data, EPA
field sampling, and analytical data collected by other EPA organizations. Slightly different
conventions were used in setting limits (see the "Statistical Support Document for Proposed Effluent
Limitations Guidelines and Standards for the Landfills Category", EPA 821-B-97-006).
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4.9.1 QA/QC Procedures
Each analytical data source received a QA/QC review before being included in the EPA analytical,
Detailed Questionnaire, and Detailed Monitoring Questionnaire databases. The specific QA/QC
activities completed for each analytical data source are discussed below.
4.9.2 Analytical Database Review
The EPA sampling program analytical data were managed by EAD's Sample Control Center. The
Sample Control Center developed and maintained the analytical database, as well as provided a
number of QA/QC functions, the findings of which were documented in data review narratives.
Completeness checks then were performed to ensure the completeness of the analytical database.
Both of these QA/QC activities are discussed below. In addition, the following paragraphs outline
the editing procedures and data conventions used to finalize the landfill analytical database, to
characterize each industry subcategory, and to develop current discharge information and pollutant
loadings.
4.9.2.1
Data Review Narratives
The Sample Control Center performed a QA/QC data review and documented their findings in the
data review narrative that accompanied each laboratory data package. The data review narrative
identified missing data and any other data discrepancies encountered during the QA/QC review. The
narratives then were checked against the data and sampling episode traffic reports to make sure no
data discrepancies were overlooked.
4.9.2.2 Completeness Checks
A data completeness check of the analytical database was performed by cross referencing the list of
pollutants requested for analysis with the list of pollutants the laboratory actually analyzed at each
sample point. This was accomplished by preparing:
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a list of all requested analytical methods and method numbers.
a list of all pollutants and CAS numbers specified under each requested analytical
method.
a schedule of analyses requested by episode for each sample point.
The purpose of the completeness check was to verify that all analyses requested were performed by
the laboratory and posted to the database in a consistent manner. The completeness check resulted
in identifying:
• any pollutant that was scheduled to be analyzed but was not analyzed.
• pollutants that were analyzed but were not scheduled to be analyzed.
• any pollutant for which the expected number of samples analyzed did not agree with
the actual number of samples analyzed.
Discrepancies then were then evaluated and resolved by subsequent QA/QC reviews. All changes
to data in the landfill analytical database were documented in a status report prepared by the Sample
Control Center entitled "Status of the Waste Treatment Industry: Landfills Database".
4.9.2.3 Trip Blanks and Equipment Blanks
Qualifiers assigned to data as a result of trip blank and equipment blank contamination were
addressed in the same way the Sample Control Center addressed contamination of lab method blanks:
Sample Results Less than Five Times Blank Results: When the sample result was less
than five times the blank result, there were no means by which to ascertain whether
the presence of the analyte could have attributed to blank contamination. Therefore,
the result was included in the database as non-detect, with a nominal detection limit
equal to the dilution-adjusted instrument detection limit.
Sample Results Greater than Five Times but Less than Ten Times Blank Results:
These data were of acceptable quality and were used to represent maximum values.
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4.9.2.4
Sample Results Greater than Ten Times Blank Results or Analyte not Detected in
Sample: The presence of the analyte in the blank did not adversely affect the data in
those cases where the sample results were greater than ten times the associated blank
results or when the analyte was not detected in associated samples. Such data were
acceptable without qualification.
Field Duplicates
Field duplicates were collected during the EPA sampling episodes to help determine the accuracy and
consistency of the sampling techniques employed in the field. In the analytical database, field
duplicate results were represented by the letter "D" preceding the sample point number. Duplicate
samples considered acceptable were combined on a daily basis using the following rules:
• If all duplicates were non-detect values, then the aggregate sample was labeled non-
detect (ND), and the value of the aggregate sample was the maximum of the ND
values.
• If the maximum detected value was greater than the maximum ND value, then the
aggregate sample was labeled NC, and the value of the aggregate sample was the sum
of the non-censored (NC) and ND values divided by the total number of duplicates
for that independent sample.
• If the maximum NC value was less 1han or equal to the maximum ND value, then the
aggregate sample was labeled ND and the value of the aggregate sample was the
maximum of the ND values.
• If all duplicates were NC values, then the aggregate sample was labeled NC and the
value of the aggregate sample was the average of the NC values.
In the laboratory, analytical precision was calculated by determining the relative percent difference
of paired spiked samples. Data was considered acceptable if the relative percent difference was
within the laboratory criteria for analytical precision.
Duplicate relative percent difference values were considered acceptable if they were within the
laboratory criteria for analytical precision plus or minus 10 percent.
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4.9.2.5
Grab Samples
Most data presented in the analytical database represent composite sample results, but other types
of results exist due to sampling requirements. Most grab sample results were represented by the
letters "A", "B", or "C" following the sample point number in the analytical database for grabs
collected on the same day. Grab samples of this nature were only collected for oil and grease/hexane
extractable material and were included when calculating average concentrations of pollutants. Grab
samples of any kind were averaged on a daily basis before being used in data analyses.
4.9.2.6
Non-Detect Data
Non-detect data were given numeric values so that they could be considered in the data analyses.
Non-detect data can be set either at the method detection limit, at the instrument detection limit, at
half of the method detection limit, or equal to zero. Detection limits can be standardized (as in the
method detection limit) or variable (as in the instrument detection limit or the sample detection limit,
which may vary depending on dilution). The instrument detection limit is the lowest possible
detection limit; the instrument cannot detect the contaminant below this level. In many cases, the
method detection limit is significantly higher than the instrument detection" limit
For the Landfills industry, all non-detect data collected from the EPA sampling episodes used in
calculations were defined as follows: 1) the value used for non-detect data was represented by the
detection limit reported in the analytical database, and 2) if the detection limit of the non-detect data
was greater than the detected results, the average was calculated using all of the data, but the results
were flagged for review on an individual basis. When flagged results were reviewed as a whole, the
high detection limits were found to be on the same order of magnitude as the detect values; therefore,
all flagged data were included in calculating averages.
4.9.2.7 Bi-Phasic Samples
In one sampling episode for a captive hazardous landfill at an industrial facility, some samples
collected became bi-phasic. For these samples, analytical results for each phase were reported
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separately. Consolidated results for the bi-phasic samples were calculated by factoring the percent
of each phase relative to the total sample volume with the results of each phase and adding the
weighted results together. Pollutants were not always detected in both the aqueous and organic
phases of a bi-phasic sample. In instances where a pollutant was detected in one phase and not in the
other phase, the detection limit was set at zero, which removed the non-detect phase from the
equation. When both phases were non-detect, the lowest of the two detection limits was used as the
result.
4.9.2.8
Conversion of Weight/Weight Data
In some cases, wastewater samples collected in the field were analyzed as solids due to criteria
specified in the analytical method. These results were reported in the database in solids units of ug/kg
or ng/kg, and needed to be converted to ug/1 and ng/1, respectively, to be used in data analysis.
Conversion factors were supplied in the database to convert these solid units (weight/weight) to
volumetric units (weight/volume).
The landfill analytical database contained a file called "solids" that contained percent solids values for
those samples associated with a result that were reported on a weight/weight basis. This percent
solids value was necessary to convert results from a weight/weight basis to a weight/volume basis.
The following formula was utilized to convert the "amount" from a weight/weight basis to a
weight/volume basis. This formula assumed a density of 1:
Amount (weight/weight) x (percent Solids/100) = Amount (weight/volume)
where,
Amount =
percent Solids =
The result contained in the "amount" field in the "result" file.
The percent solids result contained in the "percent" field in the
"solids" file.
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After conversion, the amount was expressed in weight/volume units as shown below:
Weight/Weight Units
Pg/kg
ng/kg
HS/kg
ug/g
mg/kg
Weighl/Volume Units
pg/1
ng/1
Mg/1
|jg/ml
mg/1
4.9.2.9 Average Concentration Data
All data conventions discussed above were employed when the average concentration of a group of
data was calculated. Average concentrations were calculated to develop raw waste loads, current
discharge concentrations, and percent removal values. To calculate the average concentration of a
pollutant at a particular sample point, the following hierarchy was used: 1) all non-detect data was
set at the detection limit listed in the database, 2) all weight/weight units were converted to
weight/volume units using the percent solids file, 3) all units were then converted to ug/1, 4) the bi-
phasic sample results were combined into one consolidated result, 5) both duph'cate pairs and grab
samples were combined using the rules discussed above, and 6) the weekly average was calculated
by adding all results and dividing by the number of results. -
4.9.3 Detailed Questionnaire Database Review
Each Detailed Questionnaire was reviewed for: 1) completeness, 2) internal consistency, and 3)
outliers. Outliers refer to data values that are well outside those expected for this industry. For
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example, flow rates above 10 million gallons per day would be considered suspect. In cases such as
this, the QA/QC reviewer would verify the accuracy and correctness of the data.
All information that was computerized was given a 100 percent QA/QC check to ensure that all data
were inputted properly. This was accomplished by double key entry, and any discrepancies between
the two inputted values compared with the original submission were corrected.
Additional handling procedures for Detailed Questionnaires were presented earlier in Section 4.3.2.
4.9.4 Detailed Monitoring Questionnaire Data Review
Detailed Monitoring Questionnaire data were evaluated using the same procedures outlined for the
Detailed Questionnaire process. The QA/QC steps included reviews for: 1) completeness, 2) internal
consistency, and 3) outliers.
Additional handling procedures for Detailed Monitoring Questionnaires were presented earlier in
Section 4.4.
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Table 4-2: Types of Facilities Included in EPA's Characterization and Engineering Site Visits
Ownership Type
Municipal
Commerical
Non-Commercial
(captive, intra-company)
Waste Type
Subtitle D
Subtitle C
Landfill Type
Subtitle D Non-Hazardous
(Municipal)
(Non-Municipal)
Subtitle C Hazardous
Groundwater
Characterization Site Visits
4
9
2
Engineering Site Visits*
9
8
1
Characterization Samples Collected
13
5
15
3
Characterization Samples Collected
10
(2)
(8)
5
3
15
(14)
(1)
3
0
*One engineering site visit was conducted outside the U.S.
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Treatment Technology
b
§>
£
Landfill Subc
Waste Type
Ownership Type
Hazardous
Non-Hazardous
O
1
•§
CO
Q
T3
0
m
• *— i
£
Equalization, chemical
precipitation, biological
treatment, filtration
X
X!
X
vo
C-l
vo
^r
Equalization/stripper,
chemical precipitation,
biological treatment, GAG,
filtration
X
X
X
£
vo
-4-
Equalization, filtration,
reverse osmosis
X
X
X
c-
oo
VO
•*
*
* I
f .&
&i H
•& »
r^ c
i «
X
X
X
o
ON
vo
TT
Equalization, biological
treatment
X
X
X
1
Equalization, chemical
precipitation, biological
treatment
X
X
X
a\
10
r-
•n-
o separate treatment systems
£
*
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5.0 INDUSTRY SUBCATEGORIZATION
In developing technology-based regulations for the Landfills industry, EPA considered whether a
single set of effluent limitations and standards should be established for the industry, or whether
different limitations and standards were appropriate for subcategories within the industry. The Clean
Water Act (CWA) requires EPA, in developing effluent limitations, to assess several factors,
including manufacturing processes, products, the size and age of a site, wastewater use, and
wastewater characteristics. The Landfills industry, however, is not typical of many of the other
industries regulated under the CWA that are manufacturing operations. Therefore, EPA developed
additional factors that specifically address the characteristics of landfill operations. Similarly, several
factors typically considered for subcategorization of manufacturing facilities were not considered
applicable to the Landfills industry. The factors considered for the subcategorization of the Landfills
industry are listed below:
Resource Conservation and Recovery Act (RCRA) Regulatory classification
• Types of wastes received
• Wastewater characteristics
• Facility size
• Ownership
• Geographic location
• Facility age
• Economic impacts
Treatment technologies and costs
• Energy requirements
• Non-water quality impacts
5.1 Subcategorization Approach
Based on assessment of the above factors, EPA has concluded that the most appropriate basis for
subcategorization is by landfill classification under RCRA for the reasons explained in greater detail
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below. Subcategorization on this basis incorporates many of the most relevant differences within the
Landfills industry. EPA found that the types of waste received at the landfill and the resulting
characteristics of the wastewater are most clearly correlated .with the RCRA classification of a landfill.
Additionally, this Subcategorization approach has the advantage of being the easiest to implement
because it follows the same classification previously established by EPA under RCRA and currently
in use (and widely understood) by permit writers and regulated landfills facilities.
5.2 Proposed Subcategoiies
EPA is proposing to subcategorize the Landfills industry into two subcategories as follows:
• Subcategory I: Subtitle D Non-Hazardous Landfills
• Subcategory II: Subtitle C Hazardous Landfills
Subcategory I applies to wastewater discharges from all facilities classified as RCRA Subtitle D Non-
Hazardous landfills subject either to the criteria established in 40 CFR Part 257 or 40 CFR Part 258.
Subcategory II applies to wastewater discharges from solid waste disposal facilities classified as
RCRA Subtitle C Hazardous landfills subject to the criteria in 40 CFR 264 Subpart N (Standards for
Owners and Operators of Hazardous Waste Treatment, Storage, and Disposal Facilities).
A discussion of the types of landfills regulated under these provisions of RCRA is presented in
Chapter 3 (Section 3.1 - Regulatory History of the Landfills Industry).
5.3 Other Factors Considered for Basis of Subcategorization
Before deciding to propose Subcategorization on the basis of the existing RCRA regulatory
classification for Hie Landfills industry, EPA also evaluated the appropriateness of developing
subcategories based on the other factors presented earlier in this chapter. The following subsections
present EPA's evaluation of each of tibiese factors.
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5.3.1 Types of Wastes Received
The type of solid waste that is deposited in a landfill often has a direct correlation with the
characteristics of the leachate produced by that landfill. Wastes deposited in landfills range from
municipal, non-hazardous materials, to hazardous wastes containing contaminants such as pesticides.
An analysis of the data collected as part of this study showed that there are differences in the
wastewater generated by facilities that dispose of hazardous wastes as compared to non-hazardous
wastes. These differences are reflected in both the number of pollutants of interest (as defined in
Chapter 7) identified in each subcategory and in the concentrations of these pollutants found in the
wastewaters generated. Tables presented in Chapters 6 and 7 of this document support this
comparison. Specifically, the pollutant of interest list for the Non-Hazardous subcategory contains
a total of 33 pollutants, whereas the pollutant of interest list for the Hazardous subcategory contains
63 pollutants. Pollutants targeted for analysis during EPA sampling episodes were detected
approximately 47 percent of the time at hazardous facilities versus approximately 31 percent of the
time at non-hazardous facilities. Organic pollutants and metals were routinely detected more
frequently and at higher concentrations at hazardous landfills than at non-hazardous landfills.
EPA has determined that the most practical method of distinguishing the type of waste deposited in
a landfill is achieved by utilizing the RCRA classification of landfills. As discussed in Section 5.1, the
RCRA classification selected as the basis for subcategorization is based on the types of wastes
received by the landfill: hazardous waste or non-hazardous waste. Therefore, types of waste disposed
at a landfill is a factor which is taken into consideration by the fact that it is directly encompassed by
the RCRA classification scheme and selected subcategorization method.
There also are a number of landfill cells and monofills within the Subtitle D class of non-hazardous
landfills dedicated to accept only one type of waste which includes, but is not limited to, construction
and demolition (C&D) debris, ash, or sludge. EPA is not proposing to further subcategorize Subtitle
D landfill facilities. This decision is based on two considerations: (1) similarities in waste acceptance
and leachate characteristics between monofills and other Subtitle D Non-hazardous landfills; and (2)
ease of implementation. First, EPA evaluated leachate characteristics from Subtitle D landfills
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including monofills, ashfiUs, co-disposal sites, and construction and demolition (C&D) landfills. Table
5-1 includes data from three reports1 which analyzed monofills and co-disposal sites and compares
these data to the average influent data collected from non-hazardous landfills as part of the Landfills
industry study. The data contained in these reports indicate that the leachate characteristics at
construction and demolition, co-disposal and ash monofill facilities are comparable to the leachate
characteristics from municipal solid waste landfills. Both the number and type of parameters in the
leachate do not differ among these types of facilities, and concentration levels for all pollutants are
comparable, with many parameters found at lower concentrations in the data from the construction
and demolition, co-disposal and ash monofill facilities. Therefore, EPA has concluded that untreated
leachate characteristics at these facilities were not significantly different than other non-hazardous
landfill facilities to merit subcategorization.
This is not unexpected, as the waste deposited in municipal landfills and dedicated monofills is not
mutually exclusive. Although cells at a dedicated landfill may prohibit disposal of municipal refuse,
a municipal waste landfill may also accept ash, sludge, and construction and demolition wastes. EPA
has determined that mere were no pollutants of interest identified in untreated leachate from dedicated
monofills that were not already present in municipal landfills. EPA concluded that the pollutants
proposed to be regulated for the Non-hazardous Subtitle D subcategory will control the discharges
from all types of Subtitle D landfills including monofills.
The second consideration was based on ease of implementation. As discussed in Section 5.2, the
RCRA classification scheme selected as the basis for subcategorization clearly defines non-hazardous,
hazardous, and municipal solid waste landfill facilities. However, RCRA does not make
any further distinction nor further divide the Subtitle D landfill facilities based on whether they are
monofills or if they receive multiple types of waste. Therefore, by further subcategorizing the Subtitle
D facilities into monofills and multiple waste landfills a new classification scheme would
A Study of Leachate Generated from Construction and Demolition Landfills", Department of Environmental Engineering
Sciences, University of Florida, August 1996; "Characterization of Municipal Waste Combustion Ashes and Leachates from
Municipal Solid Waste Landfills, Monofills, and Co-Disposal Sites", U.S. EPA, EPA 530-SW-87-028D, October 1987;
"Characterization of Municipal Waste Combustion Ash, Ash Extracts, and Leachates", U.S. EPA, EPA 530-SW-90-029A,
March 1990.
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be introduced to permit writers and regulated facilities. EPA concluded that the current RCRA
classification scheme is widely understood by permit writers and regulated landfill facilities, therefore,
making it the easiest of the subcategorization approaches to implement. Additionally, there are many
facilities that operate both dedicated cells (similar to monofills) and municipal solid waste (MSW)
cells at the same landfill and commingle the wastewaters prior to treatment. Establishing one
subcategory for all non-hazardous landfills will ease implementation issues and adequately control
discharges from the landfills industry.
5.3.2 Wastewater Characteristics
EPA concluded that leachate characteristics from non-hazardous and hazardous landfills differed
significantly from each other in the types of pollutants detected and the concentrations of those
pollutants. The tables supporting this conclusion are presented in Chapters 6 (Tables 6-7 through 6-
11) and 7 (Tables 7-1 and 7-2) of this document. As expected, EPA found that the leachate from
hazardous landfills contained a greater number of contaminants at higher concentrations compared
to leachate from non-hazardous landfills. This conclusion supports subcategorization based on
RCRA classification of hazardous and non-hazardous landfills.
In EPA's evaluation of contaminated groundwater, the wastewater characteristics of contaminated
groundwater from hazardous landfills differed significantly from the contaminated groundwater
characteristics at non-hazardous waste landfills, as shown in Table 5-2. Contaminated groundwater
from non-hazardous landfills contained only 16 pollutants of interest (as defined in Chapter 7)
compared to the contaminated groundwater from hazardous waste landfills which contained a total
of 54 pollutants of interest. In addition, effluent data collected in support of this proposal
demonstrate that contaminated groundwater flows at hazardous and non-hazardous facilities are, in
general, adequately treated.
Due to the site-to-site variability of contaminated groundwater, EPA has decided that the treatment
of these flows is best addressed through the corrective actions programs. Corrective actions
programs at the federal, state, and local level have the ability to consider the site-to-site variability
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of the contaminated groundwater and provide the most applicable treatment necessary to control the
contaminants. Therefore, EPA has decided to exclude contaminated groundwater from this
regulation because the Agency believes that it is better controlled through corrective actions program.
Some landfill facilities collect and treat both landfill leachate and contaminated groundwater.
Contaminated groundwater may be very dilute or may have characteristics similar in nature to
leachate. In cases where the groundwater is very dilute, it is possible that contaminated groundwater
may be used as a dilution flow. In these cases, the permit limits will be based on separate treatment
of the flows hi order to prevent dilution of the regulated leachate flows. However, in cases where
the groundwater may exhibit characteristics similar to leachate, commingled treatment is appropriate
and may be more cost effective than separate treatment. The characteristics of the contaminated
groundwater must be considered before making a determination if commingling groundwater and
leachate for treatment is appropriate.
5.3.3 Facility Size
EPA considered subcategorization of the Landfills industry on the basis of facility size and found that
landfills of varying sizes generate similar wastewaters and use similar treatment technologies. Based
upon a review of the industry provided data in the landfills database, there was no observed
correlation between waste acceptance amount or wastewater flow rate and the selection of treatment
technologies. For example, a landfill facility can add cells or increase its waste receipt rate depending
on the local market need without altering or changing the characteristics of the wastewaters
generated. In addition, the size of a landfill was not determined to be a factor in cost-effectiveness
of the regulatory options considered by EPA. Finally, EPA has determined wastewaters from landfills
can be treated to the same level regardless of facility size. EPA has not proposed a de-minimis flow
exemption for this guideline; however, EPA has accounted for landfill facilities that generate small
volumes of wastewater by estimating compliance costs for the proposed BPT/BAT/PSES options
based on treating their wastewaters off-site at a CWT facility (see Section 9.2.2).
5-6
-------
5.3.4 Ownership
EPA considered subcategorizing the industry by ownership. A significant number of landfills ate
owned by state, local, or federal governments, while others are commercially or privately owned
Landfills generally fall into two major categories of ownership: municipal or private. Landfills owned
by municipalities are primarily designed to receive non-hazardous solid waste such as municipal
waste, non-hazardous industrial waste, construction and demolition debris, ash, and sludge.
However, municipally-owned landfills may also be designed to accept hazardous wastes.
Privately-owned landfills can also provide for the disposal of non-hazardous solid waste such as those
mentioned above, and, like municipally-owned facilities, may also be designed to accept hazardous
wastes. EPA found that currently commercially- and municipally-owned landfills generally accept
and manage wastes strictly by the RCRA classification and, although there are distinct economic
differences, there is no distinction in the wastewater characteristics and wastewater treatment
employed at commercially- or municipally-owned landfills. Since all landfill types could be of either
ownership status, EPA determined that subcategorization based upon municipal and private
ownership was not appropriate.
5.3.5 Geographic Location
EPA considered subcategorizing the industry by geographic location. Landfill sites are not limited
to any one region of the United States. A table presenting the number of landfills by state is presented
in Chapter 3 (Table 3-1). While landfills from all sections of the country were included in the
Agency's survey efforts, collection of wastewater characterization data as part of EPA's sampling
episodes was limited to landfill facilities in the Northeast, South, and Midwest, where annual
precipitation is either average or above average. Although wastewater generation rates appear to
vary with annual precipitation, which is indirectly related to geographic location, a direct correlation
between leachate characteristics and geographic location could not be established due to lack of
sampling data from arid parts of the United States. However, the Agency believes that seasonal
variations in rainfall cause only minor fluctuations hi leachate characteristics due to dilution effects
and volume of leachate generated. In addition, many landfill facilities have developed site-specific
5-7
-------
best management practices to control the amount of rainwater that enters a landfill and eventually
becomes part of the leachate. These practices include proper contouring of landfill cells, extensive
use of daily cover, and capping of inactive landfill cells in order to minimize the amount of
uncontaminated rainwater that enters the landfill. EPA's data collection efforts indicate that landfill
facilities in less arid climates are more likely to use these management practices to control their
wastewater generation and flows to the on-site wastewater treatment plant. The data collected by
EPA did not indicate any significant variations in wastewater treatment technologies employed by
facilities in colder climates versus warmer climates.
EPA notes that geographic location may have a differential impact on the costs of operating a landfill.
For example, the cost of additional equipment required for the operation of the landfill or treatment
system or tipping fees charged for the hauling of waste may tend to differ from region to region.
These issues were addressed in the economic impact assessment of the proposal.
Therefore, since the effect of geographic location appears to have a minimal impact on wastewater
characteristics or can be easily addressed at minimal effort and cost, EPA determined that
subcategorization based upon geographic location was not appropriate.
5.3.6 Facility Age
EPA considered subcategorization based on the age-related changes in leachate concentrations of
pollutants for different age classes of landfills based on the evaluation of several factors. First, a
facility's wastewater treatment system typically receives and commingles leachate from several
landfills or cells of different ages. The Agency did not observe any facility that found it advantageous
or necessary to treat age-related leachates separately. Additionally, the EPA did not find any
correlation between the relative ages of the landfills and the method of leachate treatment. Second,
based on responses to the questionnaire, discussions with landfill operators, and historical data, it
appears that leachate pollutant concentrations change substantially over the first two to five years of
a landfill's operation, but then change only slowly thereafter.
5-8
-------
These two observations imply that landfill treatment systems must be designed to accommodate the
full range of concentrations and pollutants expected in influent wastewaters. EPA has concluded that
the proposed BPT/BAT/PSES treatment technologies can successfully treat the variations in landfill
wastewaters likely to occur due to age-related changes in the leachate. EPA also has taken into
account the ability of treatment systems to accommodate age-related changes in raw leachate
concentrations and pollutants, as well as short-term fluctuations, by proposing effluent limitations (for
those regulated pollutants having long term sampling data) that reflect the variability observed in
monitoring data spanning 12 to 36 months. Additionally, age-related effects on treatment
technologies, costs, and pollutant loads were addressed by utilizing data collected from a variety of
landfills of various ages and types of operation (e.g., closed/capped, inactive, or active).
EPA also evaluated sampling data collected from hazardous and non-hazardous landfill facilities of
different ages to compare general leachate characteristics based on conventional and selected
nonconventional pollutant parameters, as shown in Table 5-3. While certain pollutant parameters
follow the generally accepted pattern of younger landfills having leachates with higher pollutant
concentrations, as shown for TOC and TSS for both municipal and hazardous facilities, data for other
parameters such as COD for the hazardous facilities and BOD for the municipal facilities show the
opposite trend. However, in general, these pollutant concentrations are within the same order of
magnitude and the Agency believes that this variability in wastewater characteristics can be
adequately handled in the proposed BPT/BAT/PSES treatment options.
Based on this analysis of the effects of age on wastewater characteristics, EPA determined that
subcategorization based on facility age is not appropriate.
5.3.7 Economic Characteristics
EPA also considered subcategorizing the industry based on the economic characteristics of the landfill
facilities. If a group of facilities with common economic characteristics, such as revenue size, was
in a much better or worse financial condition than others, EPA could consider subcategorization on
economics. However, based on the results of the detailed questionnaires, financial conditions of
5-9
-------
compliance costs associated with the proposed BPT/BAT/PSES regulations did not inordinately
effect any particular segment of the landfills industry. Therefore, EPA determined that
subcategorization based on the economic characteristics of landfills facilities was not justified.
5.3.8 Treatment Technologies and Costs
Wastewater treatment for this industry ranges from primary systems such as equalization, screening,
and settling, to advanced tertiary treatment systems such as filtration, carbon adsorption, and
membrane separation. EPA found that the selected treatment technology employed at a facility was
dependent on wastewater characteristics and permit requirements. Landfills with more complex
mixtures of toxic pollutants in their wastewaters generally had more extensive treatment systems and
may utilize several treatment processes (e.g., facilities with high levels of both organic and inorganic
pollutants may employ both a chemical and biological treatment system). However, subcategorizing
by the waste type received by a landfill as outlined in the RCRA classification of landfills is less
difficult to implement and results in addressing the same factors as using treatment processes
employed. As a result, EPA did not consider treatment technologies or costs to be a basis for
subcategorization.
5.3.9 Energy Requirements
The Agency did not subcategorize based on energy requirements because energy usage was not
considered a significant factor in this industry and is not related to wastewater characteristics. Energy
costs resulting from this regulation were accounted for in the costing section of this development
document (Chapter 9) and in the economic impact assessment.
5-10
-------
5.3.10 Non-Water Quality Impacts
The Agency evaluated the impacts of this regulation on the potential for increased generation of solid
waste and air pollution. The non-water quality impacts did not constitute a basis for
subcategorization. Non-water quality impacts and costs of solid waste and air pollution control are
included in the economic analysis and regulatory impact analysis for this regulation. See Chapter 10
for more information regarding non-water quality impacts.
5-11
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Table 5-3: Comparision of Untreated Wastewater Charcteristics at Landfills of Varying Age
Analyte (mg/1)
Ammonia
BODS
COD
TOC
TSS
Subtitle D Non-Hazardous Municipal
Year Landfill Began
1971
245
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Accepting Waste
1986
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Subtitle C Hazardous
Year Landfill Began Accepting Waste
1968 1980
460 557
955 4250
2400 1920
799 5850
31 111
Note: Samples collected during EPA sampling episodes 1994-95
5-17
-------
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6.0 WASTEWATER GENERATION AND CHARACTERIZATION
In 1994, under the authority of Section 308 of the Clean Water Act (CWA), the Environmental
Protection Agency (EPA) distributed the "Waste Treatment Industry Questionnaire Phase II:
Landfills" to 252 facilities that EPA had tentatively identified as possible generators of landfill
wastewater. Some of the facilities employed on-site wastewater treatment, others did not. These
faculties were selected for survey purposes to represent a total of 1,024 potential generators of
landfill wastewater. A total of 220 questionnaire respondents generated landfill leachate in 1992.
•This section presents information on wastewater generation at these facilities based on the
questionnaire responses. In addition, this section also summarizes the information on wastewater
characteristics for landfill facilities that were sampled by EPA and for those facilities that provided
self-monitoring data.
6.1
Wastewater Generation and Sources of Wastewater
Landfill facilities do not generate "process wastewater" as defined in 40 CFR 122.2 as "any water
which, during manufacturing or processing, comes into direct contact with or results from the
production or use of any raw material, by-product, intermediate product, finished product or waste
product" in the traditional sense. This definition of process wastewater is used for manufacturing or
processing operations; since landfill operations do not include or result in "manufacturing processes"
or "products", EPA refers to the wastewater treated at landfill facilities as landfill generated
wastewaters.
In general, the types of wastewater generated by activities associated with landfills and collected for
treatment, discharge, or reuse are: leachate, landfill gas coridensate, truck/equipment washwater,
drained free liquids, laboratory derived wastewaters, floor washings, recovering pumping wells,
contaminated groundwater, and storm water runoff. For the purposes of the Landfill industry study,
all of these wastewater sources are considered "in-scope" except for contaminated groundwater and
non-contaminated storm water.
6-1
-------
In 1992, approximately 23 billion gallons of wastewater was generated at landfill facilities.
Approximately 7.1 billion gallons of this wastewater is considered "in-scope". The remaining 15.9
billion gallons of wastewater generated at landfills consists of contaminated groundwater and non-
contaminated storm water. The primary sources of wastewater at landfills are defined below.
Landfill leachate as defined in 40 CFR 258.2, is liquid that has passed through or emerged from solid
waste and contains soluble, suspended, or miscible materials removed from such waste. Over time,
the seepage of water through the landfill as a result of precipitation may increase the mobility of
pollutants and thereby increase the potential for their movement into the wider environment. As
water passes through the layers of waste, it may "leach" pollutants from the disposed waste. This
mobility may present a potential hazard to public health and the environment (e.g., groundwater
contamination). One measure used to prevent the movement of toxic and hazardous waste
constituents from a landfill is a landfill liner operated in conjunction with a leachate collection system.
Leachate is typically collected from a finer system placed at the bottom of the landfill. Leachate also
may be collected through the use of slurry walls, trenches, or other containment systems. The
leachate generated varies from site to site based on a number of factors including the types of waste
accepted, operating practices (including shedding, daily cover and capping), the depth of fill,
compaction of wastes, annual precipitation, and landfill age. Landfill leachate accounts for over 95
percent of the total volume of in-scope wastewaters.
Landfill gas condensate is a liquid which has condensed in the landfill gas collection system during
the extraction of gas from within the landfill. Gases such as methane and carbon dioxide are
generated due to microbial activity within the landfill and must be removed to avoid hazardous
conditions. The gases tend to contain high concentrations of water vapor which is condensed in traps
staged throughout the gas collection network. The gas collection condensate contains volatile
compounds and typically accounts for a small portion of flow from a landfill.
Truck/equipment washwateris generated during either truck or equipment washes at landfills. During
routine maintenance or repair operations, trucks and/or equipment used within the landfill (e.g.,
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loaders, compactors, or dump trucks) are washed and the resultant washwaters are collected for
treatment In addition, it is common practice in hazardous landfills to wash the wheels, body, and
undercarriage of trucks used to deliver the waste to the open landfill face upon leaving the landfill.
On-site wastewater treatment equipment and storage tanks also are cleaned periodically and their
associated washwaters are collected. Floor washings generated during routine cleaning and
maintenance of the facility also are collected for treatment
Drained free liquids are aqueous wastes drained from waste containers (e.g., drums, trucks, etc.)
or wastewater resulting from waste stabilization prior to landfilling. Landfills that accept
containerized waste may generate this type of wastewater. Drained free liquids are collected and
usually combined with other landfill generated wastewaters for treatment at the wastewater treatment
plant.
Laboratory-derived wastewater is generated, from on-site laboratories which characterize incoming
waste streams and monitor on-site treatment performance. This source of wastewater is minimal and
is usually combined with leachate and other wastewaters and treated at the wastewater treatment
plant.
Contaminated storm water is runoff that comes in direct contact with the solid waste, waste handling
and treatment areas, or wastewater flows that are covered under this rule. Storm water that does not
come into contact with these areas was not considered to be within the scope of this study.
Landfill operations also generate and discharge wastewaters that are considered out of the scope of
the proposed regulation. These sources include contaminated groundwater and non-contaminated
storm water. The exclusion of these flows is discussed in Chapter 2: Scope of the Regulation. A
brief description of these wastewaters is presented below.
Contaminated groundwater is water below the land surface in the zone of saturation that has been
contaminated by landfill leachate. Contaminated groundwater occurs at landfills without liners or at
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facilities that have released contaminants from a liner system and is then collected and treated by
landfills. Groundwater also can infiltrate the landfill or the leachate collection system if the water
table is high enough to penetrate the landfill area.
Non-contaminated (non-contact) storm water includes storm water that flows off the cap or cover
of the landfill and does not come in direct contact with solid waste, waste handling and treatment
areas, or vvastewater flows which are covered under this rule.
These landfill generated waste streams are considered out of the scope of the landfills regulations for
the following reasons. EPA found that pollutants in contaminated groundwater flows are treated to
very low levels prior to discharge. Therefore, it was concluded that, whether as a result of corrective
action measures taken pursuant to Resource Conservation and Recovery Act (RCRA) authority or
State action to clean up contaminated landfill sites, landfill discharges of treated contaminated
groundwater are being adequately controlled, and that further regulation under this proposed rule
would be redundant and unnecessary. As for non-contaminated storm water, this runoff includes
storm water that flows off the cap or cover of the landfill and does not come in direct contact with
the waste. Therefore, this wastewater is considered out of the scope of landfill regulation because
it is already covered by other EPA regulations.
Many landfill facilities, particularly hazardous landfills, commingle waste streams such as
contaminated groundwater, non-contaminated storm water, or process wastewater from on-site
industrial operations with in-scope landfill generated wastewaters prior to or after treatment. These
out-of-scope waste streams are not included as wastewater sources reviewed for effluent limitations
guidelines and standards for this rulemaking. The flow monitoring data received from facilities with
commingled waste streams were reviewed to determine if the discharge streams included out-of-scope
wastewater. In cases where the waste streams included greater than 15 percent out-of-scope
wastewater, the monitoring data were not used to characterize landfill generated wastewater.
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6.2 Wastewater Flow and Discharge
Tables 6-1 and 6-2 present national estimates of the flows for primary wastwater sources found at
landfills reported in Section A of the Waste Treatment Industry 308 Questionnaire Phase II: Landfills.
A brief discussion of national estimates and how these estimates are calculated is presented in Chapter
3, Section 3.2.1. The flows in both tables are reported by subcategory: Non-Hazardous (broken
down into Subtitle D municipal solid waste and non-municipal solid waste facilities) and Hazardous;
and by discharge type: direct, indirect, and zero.
Direct discharge facilities are those that discharge their wastewaters directly into a receiving stream
or body of water. Based on national estimates, there were no direct discharging hazardous landfills
identified in the Landfills industry study; therefore, this discharge type has been omitted from the
Hazardous subcategory on Table 6-1 and is reported as a zero on Table 6-2. Indirect discharging
facilities discharge their wastewater indirectly to a publicly-owned treatment works (POTW). Zero
or alternative discharge facilities use treatment and disposal practices that result in no discharge of
wastewater to surface waters. Disposal options for landfill generated wastewater include off-site
treatment at another landfill wastewater treatment system or a Centralized Waste Treatment facility,
deep well injection, incineration, evaporation, land application, and recirculation back to the landfill.
Table 6-1 presents wastewater flows by subcategory and discharge type for the different types of
wastewater generated by landfills in 1992. Total flows are reported for wastewaters treated on-site
and off-site, discharged untreated to a POTW or surface water, and recycled flows that are put back
into the landfill. Wastewater flows identified as "Other" treatment include evaporation, incineration,
or deep well injection. The national estimates presented in Tables 6-1 and 6-2 are based on 176 of
the 220 facilities that generate and treat landfill leachate; the remaining 44 facilities are excluded from
the proposed landfill regulation as discussed in Chapter 2.
In-scope wastewater flows from Table 6-1 were combined and presented in Table 6-2. Table 6-2
does not include out-of-scope flows from contaminated groundwater or storm water. National
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estimates are presented for the in-scope wastewater flows and the associated number of non-
hazardous and hazardous facilities by subcategory and discharge type.
6.2.1 Wastewater Flow and Discharge at Subtitle D Non-Hazardous Landfills
Approximately 6.7 billion gallons of in-scope wastewater were generated at non-hazardous landfills
in 1992. Flows collected from leachate collection systems are the primary source of wastewater,
accounting for over 98 percent of the in-scope wastewaters generated at non-hazardous landfills.
Landfill facilities have several options for the discharge of their wastewaters. EPA estimates that
there are 158 Subtitle D non-hazardous facilities discharging wastewater directly into a receiving
stream or body of water, accounting for 1.2 billion gallons per year. In addition, there are 762
facilities discharging wastewater indirectly to a POTW, accounting for 4.5 billion gallons per year.
Also, there are a number of facilities which use treatment and disposal practices that result in no
discharge of wastewater to surface waters. The Agency estimates that there are 343 of these zero or
alternative discharge facilities. Several zero discharge or alternative facilities in the Non-Hazardous
subcategory recycle wastewater flows back into the landfill. The recirculation of leachate is generally
believed to encourage the biological activity occurring in the landfill and accelerate the stabilization
of the waste. The recirculation of landfill leachate is not prohibited by federal regulations, although
many states have prohibited the practice. EPA estimates that 349 million gallons per year are
recirculated back to Subtitle D non-hazardous landfill units.
6.2.2 Wastewater Flow and Discharge at Subtitle C Hazardous Landfills
Approximately 367 million gallons of in-scope wastewater were generated at hazardous landfills in
1992. Flows collected from leachate collection systems are the primary source of wastewater,
accounting for approximately 74 percent of the in-scope wastewaters generated at hazardous landfills,
and 24 percent of the flows are generated by routine maintenance activities such as truck/equipment
washing and floor washing.
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Landfill facilities have several options for the discharge of their waste-waters. EPA's survey of the
Landfills industry did not identify any hazardous landfills covered by the proposed guideline which
discharge in-scope wastewaters directly to surface waters. EPA estimates that there are 6 facilities
discharging wastewater indirectly to a POTW, accounting for 40 million gallons per year.
The Agency estimates that 141 hazardous landfill facilities use zero or alternative discharge disposal
options. EPA estimates that 103 facilities ship wastewater off-site for treatment, often to a treatment
plant located at another landfill or to a Centralized Waste Treatment facility. Shipping off-site
accounts for 9 million gallons per year of wastewater. Another 37 facilities use underground injection
for disposal of their wastewaters, accounting for 312 million gallons per year; and 1 facility solidifies
less than 0.1 million gallons per year of landfill wastewater.
6.3
Wastewater Characterization
The information reported in this section was collected through the EPA sampling program and data
supplied by the Landfills industry via technical questionnaires. EPA sampling programs consisted of
five-day events at landfills with selected BAT treatment systems (where the raw leachate and
treatment system points were sampled) as well as one-day events to characterize raw leachate quality
at selected types of landfill facilities. Industry provided data, as supplied in the Detailed
Questionnaire and in the Detailed Monitoring Questionnaire responses, were also used to characterize
landfill generated wastewaters. In addition, data collected as part of the Centralized Waste Treatment
Industry study (see reference 31) and Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA) groundwater study (see reference 25) were used in the characterization of
the wastewaters from hazardous landfill facilities. These data sources are discussed in detail in
Chapter 4 as well as the QA/QC procedures and editing rules used to evaluate these data. The raw
wastewater Master File then was developed for each subcategory by combining the influent data from
all of the available data sources to characterize the raw wastewater by subcategory.
This section presents background information on the types of wastewaters generated at landfill
facilities and the factors that affect the wastewater characteristics, pollutant parameters analyzed and
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detected at EPA sampling episodes, the methodology for developing the Master File, and the
pollutant parameters identified in typical landfill generated wastewaters along with the minimum and
maximum concentrations of these pollutants. This section also presents available literature data on
the wastewater characteristics of Non-Hazardous subcategory landfill generated wastewaters.
6.3.1 Background Information
Landfill generated wastewaters are composed of several wastewater sources that have been discussed
in Section 6.1, including landfill leachate, landfill gas condensate, truck/equipment washwater, drained
fiee liquids, laboratory-derived wastewater, floor washings, recovering pumping wells, contaminated
groundwater, and storm water runoff. Wastewaters within the scope of the proposed landfill
regulation include the above mentioned sources with the exception of contaminated groundwater and
non-contaminated storm water. The primary sources of in-scope landfill generated wastewater are
discussed below.
6.3.1.1 Landfill Leachate
Leachate is the liquid which passes through or emerges from solid waste, and contains soluble,
suspended, or miscible materials removed from such waste. Leachate quality is affected by several
factors that vary depending on each individual landfill, including:
• types of waste accepted/deposited
• operating practices (shredding, cover, and capping)
• amount of infiltration
depth of fill
• compaction
age
Waste types received for disposal are the most representative characteristic of a landfill and,
therefore, of the wastewater generated, since the main contaminants in the wastewater are derived
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from the materials deposited into the fill (see Chapter 5: Industry Subcategorization). Infiltration and
age primarily affect the concentration level of contaminants in the leachate. The remaining factors
mainly influence the rate of infiltration.
Characterization of landfill leachate is a function of both the concentration of contaminants in the
leachate and the volume of leachate generated. On a relative basis, the highest concentrations of
contaminants are typically present in the leachates of new or very young landfills. However, tte
amount (i.e., the mass) of pollutants are not necessarily the highest in the life of a landfill because new
landfills generally generate low volumes of leachate. As the volume of waste approaches the field
capacity of the landfill and the production of leachate increases, both the pollutant loadings (mass x
concentrations) and the concentrations of certain contaminants (mostly organic pollutants) increase.
The concentration increase is attributed to the onset of decomposition activities within the landfill and
to the leachate traversing the entire depth of refuse. Therefore, the largest expected loadings of
contaminants from a typical landfill result during a period of high leachate'production and high
contaminant levels (see reference 13). The exact periods of varying leachate production cannot be
quantified readily but are site-specific and dependent on each of the above variables.
Over a period of time (as the landfill ages and leaching continues) the concentration of contaminants
in the leachate decreases (see reference 13). Substantial quantities of leachate may continue to be
produced by the landfill; however, loadings are lower due to the lower concentrations of
contaminants remaining in the landfill. As decomposition of the landfill continues, a stabilized state
of equilibrium is attained where further leaching produces leachate with lower loadings than during
the period of peak leachate production. This stabilized state is presumably the result of
decomposition of landfill waste by indigenous microorganisms, which will remove many of the
contaminants usually susceptible to further leaching.
Biological decomposition of landfill municipal refuse has been examined by many researchers and has
been modeled after the anaerobic breakdown of other organic wastes. The following discussion of
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the decomposition process has been adapted from a report on the characteristics of landfill leachate
prepared by the Wisconsin Department of Natural Resources (see reference 13).
Biological activity occurs in a landfill shortly after deposition of organic material. At first, wastes
high in moisture content decompose rapidly under aerobic conditions, creating large amounts of heat.
As oxygen is depleted, the intermediate anaerobic stage of decomposition begins. This change from
aerobic to anaerobic conditions occurs unevenly through the landfill and depends upon the rate of
oxygen diffusion in the fill layers. The first stage of anaerobic decomposition converts complex
organic wastes to soluble organic molecules. This solubilization is performed by extracellular
enzymes. Once the organics are solubilized, the second stage of anaerobic decomposition converts
them to simple organic molecules, the most common of which are organic acids (such as acetic,
propionic, and butyric acids). Leachate percolating through a landfill can amass these organic acids,
resulting in decreased pH of the leachate and increasing oxygen demand. Anaerobic activity also can
lower the reduction oxidation (redox) status of the wastes which, under low pH conditions, can cause
an increase in inorganic contaminants. Eventually, bacteria within the landfill begin converting the
organic acids to methane. The removal of organic acids from the landfill increases the pH of the
leachate which can lead to a decrease in the solubility of inorganic contaminants, lowering inorganic
concentrations in the leachate.
A landfill's age or degree of decomposition may, in certain circumstances, be ascertained by observing
the concentration of various leachate indicator parameters, such as BOD5, TDS, or the organic
nitrogen concentration. The concentrations of these leachate indicator parameters can vary over the
decomposition life of a landfill. Using these indicator parameters alone does not take into account
any refuse-filling variables, such as processing and fill depth". To compensate for these additional
variables, ratios of leachate parameters over time were examined by researchers (see reference 13).
One such ratio is the ratio of BOD5 to COD in the leachate. Leachates from younger landfills
typically exhibit BOD5 to COD ratios of approximately 0.8, while older landfills exhibit a ratio as low
as 0.1. The decline in the BOD5 to COD ratio with age is due primarily to the readily decomposable
material (phenols, alcohols) degrading faster than the more recalcitrant compounds (heavy molecular
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weight organic compounds). As a result, the BOD5 of the leachate will decrease faster than the COD
as the landfill ages. Other ratios examined that reportedly decrease over time include: volatile solids
to fixed solids, volatile acids to TOC, and sulfate to chloride (see reference 13).
It is common to find that the sum of individual organic contaminants does not always match the
measured TOC and/or COD value. As demonstrated by data collected by EPA for this guideline, the
sum of the individual organic pollutants represent only a certain percentage of the TOC and/or COD
value, as shown in Tables 6-7, 6-8, 6-9, and 6-11 presented later in this chapter. Compounds that
comprise this difference are not always readily identified due to the complex nature of leachate and
due to the presence of other organic compounds found in leachate. A myriad of organic compounds
exist in decomposing refuse and most of the organics in leachate are soluble. Reportedly, free volatile
acids constitute the main organic fraction in leachate (see reference 13). However, other organic
compounds have been identified in landfill leachates including carbohydrates, proteins, and humic and
fulvic-like substances. Gaps in mass balance results are typically attributed to these compounds.
Responses to EPA's Detailed Questionnaire indicate that 1,659 in-scope landfills collect leachate at
a mean daily flow of 14,000 gallons per day. In 1992, approximately 6.9 billion gallons of landfill
leachate were generated by landfills in the United States. Of this 6.9 billion gallons, approximately
1.7 billion gallons were treated on-site, 475 million gallons were treated off-site, 3.6 billion gallons
were sent untreated to POTWs, 417 million gallons were sent untreated to a surface water, 350
million gallons were recycled back to the landfill, and 358 million gallons were treated or disposed
by other methods.
6.3.1.1.1 Additional Sources of Non-Hazardous Leachate Characterization Data
Various sources of non-hazardous landfill leachate characteristics exist in published literature. Most
of these are from studies taken at an isolated range of municipal landfills in the 1970s and 1980s.
Data presented in these reports on leachate characteristics are typically expressed in ranges due the
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variability of the results. The range of values, as well as the lack of specific information on factors
affecting leachate results (e.g., sampling methods, analytical methods, landfill waste types, etc.) limit
the usefulness of these data. However, these data are mentioned as additional background
information in support of EPA's characterization activities. Table 6-3 presents a summary of available
municipal leachate characteristic data from the following sources:
Five published papers: George, 1972; Chian and DeWalle, 1977; Metry and Cross, 1977;
Cameron, 1978; and Shams-Korzani and Henson, 1993.
• McGinley, Paul M. and Kmet, P. "Formation, Characteristics, treatment and Disposal of
Leachate from Municipal Solid Waste Landfills." Wisconsin Department of Natural
Resources Special Report, August 1984, and
• Sobotka & Co., Inc. Case history data compiled and reported to U.S. EPA's Economic
Analysis Branch, Office of Solid Waste, July 1986.
The variability and high pollutant concentrations in older landfill leachate characterization data can
be attributed to landfills that accepted waste prior to the enactment of RCRA in 1980. Landfills in
operation prior to this date may have disposed of a multitude of different industrial and/or toxic
wastes in addition to municipal solid waste. The disposal of these high-strength wastes could account
for the large variability observed in leachate characteristics data collected from municipal landfills in
this period. After the promulgation of RCRA, controls were established that specified the type and
characteristics of wastes that may be received by either a hazardous (Subtitle C) or non-hazardous
(Subtitle D) facility (see Chapter 3: Section 3.1 for the discussion on regulatory history). Control
measures, such as leachate collection systems, also have been mandated under RCRA for both types
of landfills. By instituting the acceptance criteria and leachate control standards under RCRA, the
characteristics of the leachate from both hazardous and non-hazardous landfills will not vary as
greatly as observed in landfills prior to 1980. The smaller concentration range for pollutants from
landfills in operation since RCRA became effective is supported by the data collected by EPA
Whereas pollutant variability was observed in EPA data, it was not as great as found in the literature
data collected from older facilities. Data collected as part of the Landfill Rulemaking effort were
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within the specified ranges as found in previous literature sources, however, this data did not exhibit
the large variability that is indicative of older pre-RCRA landfill operations.
6.3.1.2 Landfill Gas Condensate
Landfill gas condensate forms in the collection lines used to extract and vent/treat landfill gas.
Condensate collects at low points in the system and is usually removed by pumping to the on-site
wastewater holding tank or treatment system. Responses to EPA's Detailed Questionnaire indicate
that 158 landfills collect landfill gas condensate at a mean daily flow of 510 gallons per day. In 1992,
approximately 23 million gallons of landfill gas condensate were generated by landfills in the United
States. Of this 23 million gallons, approximately 20 million gallons were treated on-site, 1.7 million
gallons treated off-site, and 0.8 million gallons were sent untreated to POTWs. Of the 155 facilities
collecting gas condensate, 66 commingle condensate with leachate for treatment on-site, 79 facilities
do not treat the condensate on-site, and 10 facilities treat landfill gas condensate separately from other
landfill generated wastewaters.
Landfill gas condensate represents a small amount of the total wastewater flow volume for the
industry. Hazardous waste landfills produce 9 million gallons/year of gas condensate, or about 3
percent of the leachate flow volume. Municipal waste landfills produce 14 million gallons/year of gas
condensate, or about 0.2 percent of the leachate flow volume.
Of the 37 respondents to the Detailed Questionnaire that collect landfill gas condensate, five facilities
treat the condensate separately from leachate. Types of condensate treatment include equalization,
neutralization, oil-water separation, GAG, and air stripping. All five facilities discharged the treated
waste stream indirectly to a POTW. Table 6-4 presents landfill gas condensate monitoring data
provided in the Detailed Questionnaire from two facilities that collect and treat landfill gas condensate
separately from other landfill generated wastewaters. Facility 16012 presented landfill gas condensate
monitoring data after treatment by hydrocarbon/aqueous phase separation and caustic neutralization,
and facility 16015 presented monitoring data after treatment by equalization, caustic neutralization,
and carbon adsorption.
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6.3.1.3 Truck and Equipment Washwater
Truck and equipment washwater is generated during either truck or equipment washes at the landfill.
Depending on the type and usage of the vehicle/equipment cleaned and the type of landfill, the
washwater volume and characteristics can vary greatly. For hazardous and non-hazardous landfill
facilities, washwaters will typically be more dilute in strength hi comparison to typical leachate
characteristics and contain mostly solids. Contaminants in the washwater are attributed to the
insoluble solids, consisting of mostly inorganics, metals, and low concentrations of organic
compounds. Since truck and equipment washwaters tend to contain the same constituents as the
waste being landfilled, and are similar in characteristic to the landfill leachate, they are typically
combined for treatment with leachate and other landfill generated wastewaters.
Responses to EPA's Detailed Questionnaire indicate that 356 in-scope landfills collect truck and
equipment washwater at a mean daily flow of 864 gallons per day. In 1992, approximately 102
million gallons of truck and equipment washwater were generated by landfills in the United States.
Of this 102 million gallons, approximately 38 million gallons were treated on-site, 9 million gallons
were sent untreated to POTWs, 1.5 million gallons were either treated off-site, recycled back to the
landfill, or sent untreated to a surface water, and 53 million gallons were treated or disposed by other
methods.
6.3.1.4 Drained Free Liquids
Drained free liquids are liquids drained from containerized waste prior to landfilling. Wastewater
characteristics and volume of drained free liquids vary greatly depending upon the contents and origin
of the waste. However, they will have the characteristics of the containerized waste and, therefore,
similar characteristics to landfill leachate. This also is true of other wastewaters generated by waste
processing activities, such as waste stabilization. Waste stabilization includes the chemical fixation
or solidification of the solid waste. Wastewaters generated from these activities include decant from
the waste treated and any associated rinse waters. These waste processing wastewaters are collected
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separately and are then combined with leachate and other landfill operation wastewaters for treatment
at the wastewater treatment facility.
Responses to EPA's Detailed Questionnaire indicate that 25 in-scope landfills collect drained free
liquids at a mean daily flow of 5 gallons per day. In 1992, approximately 0.6 million gallons of
drained free liquids were generated by landfills in the United States. Of this 0.6 million gallons,
approximately 521,000 gallons were recycled back to the landfill and 47,000 gallons were treated or
disposed by other methods.
6.3.2 Pollutant Parameters Analyzed at EPA Sampling Episodes
The EPA conducted 19 sampling episodes at 18 landfill facilities. Five episodes were conducted at
hazardous landfill facilities and 13 at non-hazardous facilities. One-day sampling episodes were
conducted for the purpose of collecting raw wastewater samples to characterize landfill generated
wastewaters. Samples collected during the week-long sampling episodes included raw wastewater
samples as well as intermediate and effluent samples to evaluate the entire wastewater treatment
system. Chapter 4 discusses these data collection activities in further detail.
Table 6-5 presents the pollutants analyzed at the one-day and week-long sampling episodes. A total
of 470 pollutants were analyzed for in the raw wastewater, intermediate, and treated effluent waste
stream samples, including 232 toxic and nonconventional organic compounds, 69 toxic and
nonconventional metals, 4 conventional pollutants, and 165 toxic and nonconventional pollutants
including pesticides, herbicides, dioxins, and furans. The list of pollutants analyzed are included under
the following analytical methods: method 1613 for dioxins/furans; method 1620 for metals; method
1624 for volatile organics; method 1625 for semivolatile organics; and methods 1656, 1657, and 1658
for pesticides/herbicides, as well as classical wet chemistry methods.
Table 6-6 presents the list of pollutants analyzed at EPA sampling episodes by subcategory and
episode number and whether they were detected in the facility's raw wastewater. If a pollutant was
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not detected it is reported on the table as ND, if a pollutant was detected it is reported as a blank, and
pollutants that were not sampled are represented by a dash.
Composite samples were collected at the week-long sampling events at episodes 4626, 4667, 4687,
4690, 4721, and 4759; grab samples were collected at the remaining 11 one-day sampling events.
A preliminary list of pollutants of interest was developed by reducing the list of 470 pollutants by the
number of pollutants that were never detected at any facility in a subcategory. For the Non-
Hazardous subcategory, a total of 316 pollutants were analyzed for but never detected in the raw
wastewater at Subtitle D municipal facilities, and 324 pollutants were never detected in the raw
wastewater at Subtitle D non-municipal facilities. For the Hazardous subcategory, a total of 250
pollutants were never detected in the raw wastewater. Therefore, out of the 470 pollutants initially
analyzed for, a total of 154 pollutants were detected at least once at Subtitle D municipal facilities;
146 pollutants were detected at least once at Subtitle D non-municipal facilities; and 220 pollutants
were detected at least once at hazardous facilities. Using the editing criteria which is presented hi
detail in Chapter 7, this preliminary list of pollutants of interest was reduced to the final list of 33
pollutants of interest for the Non-Hazardous subcategory (32 pollutants of interest for Subtitle D
municipal facilities and 10 pollutants of interest for Subtitle D non-municipal facilities); and 63
pollutants of interest for the Hazardous subcategory. These pollutants are presented on Tables 6-7
and 6-8 and are discussed further below.
6.3.3 Raw Wastewater Characterization Data
EPA compiled raw wastewater sampling data obtained from the following sources: EPA sampling;
the Detailed Questionnaire; the Detailed Monitoring Questionnaire; the CERCLA groundwater
database; and the Centralized Waste Treatment Industry (CWT) database in order to characterize
wastewater from the Landfills industry.
EPA then reviewed each data source to determine if the data was representative of landfill generated
wastewater. First, EPA selected only those sample points corresponding to raw wastewater by
reviewing treatment flow diagrams and sampling programs at each landfill facility. Second, EPA used
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several criteria to eliminate sampling data not considered representative of raw landfill wastewaters. '
Only those data collection points which sampled wastewaters containing at least 85 percent leachate
and/or gas condensate were included in the characterization study. In this way, facilities that sampled
wastestreams containing mostly storm water or sanitary wastewaters were eliminated. Also, any
sample point containing industrial process wastewater was eliminated. This eliminated the possibility
of finding pollutants that may not have originated in -a landfill.
Next, EPA grouped all data points according to the classification of the landfill, e.g. municipal solid
waste, hazardous waste, or Subtitle D non-municipal solid waste. Tables 6-9 through 6-1 1 present
the range of all values compiled for raw wastewaters, listed by landfill type.
In several instances, EPA conducted sampling at a facility that also provided data in the technical
questionnaires. In these cases, EPA compiled all data at that landfill from the different sources to
obtain one average concentration for each pollutant at each landfill. The median concentration of
each landfill average concentration was then calculated to determine the median industry raw
wastewater concentrations. These median values are presented in Tables 6-7 and 6-8 as the raw
wastewater Master File.
6.3.4 Conventional, Toxic, and Selected Nonconventional Pollutant Parameters
The Clean Water Act defines different types of pollutant parameters used to characterize raw
wastewater. These parameters include conventional, nonconventional, and toxic pollutants.
Conventional pollutants found in landfill generated wastewaters include:
Total Suspended Solids (TSS)
• 5-day Biochemical Oxygen Demand (BOD5)
Oil and Grease (measured as Hexane Extractable Material)
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Total solids in wastewater is defined as the residue remaining upon evaporation of the liquid at just
above its boiling point TSS is the portion of the total solids that can be filtered out of solution using
a 1 micron filter. Raw wastewater TSS in leachate is a function of the type and form of wastes
accepted for disposal at landfill facilities. The concentration of TSS also is influenced by the landfill
design and operational parameters such as depth of fill, compaction, and capping. BOD5 is one of
the most important gauges of pollution potential of a wastewater and varies with the amount of
biodegradable matter that can be assimilated by biological organisms under aerobic conditions. The
nature of the chemicals contained in landfill generated wastewaters affects the BOD5 due to the
differences in susceptibility of different molecular structures to microbiological degradation. Landfill
generated wastewater containing compounds with lower susceptibility to decomposition by
microorganisms tend to exhibit lower BOD5 values, even though the total organic loading may be
much higher as compared to wastewaters exhibiting substantially higher BOD5 values. For example,
a landfill generated wastewater may have a low BOD5 value while at the same time exhibiting a high
TOG or COD concentration. Raw wastewater BODS values can vary depending on the waste
deposited in the landfill and the landfill age, as noted previously in Section 6.3.1.1.
The pH of a solution is a unitless measurement which represents the acidity or alkalinity of a
wastewater stream (or aqueous solution) based on the disassociation of the acid or base in the
solution into hydrogen (H*) or hydroxide (OH") ions, respectively. Raw wastewater pH can be a
function of the waste deposited in a landfill but can vary depending on the conditions within the
landfill, as noted previously in Section 6.3.1.1. Fluctuations in pH are controlled readily by
equalization followed by neutralization. Control of pH is necessary to achieve proper removal of
pollutants in treatment systems such as metals precipitation and biological treatment systems.
Oil and grease also may be present in selected landfill generated wastewaters. Proper control of oil
and grease is important because it can interfere with the operation of certain wastewater treatment
system processes such as chemical precipitation and the settling operations in biological systems. If
it is not removed prior to discharge, excessive levels of oil and grease can interfere with the operation
6-18
-------
of POTWs and can create films along surface waters, disrupting the biological activities in those
waterways.
Table 6-9 presents observed minimum and maximum concentration data for TSS, BOD5, and oil and
grease for each landfill subcategory and the observed minirnum and maximum values for pH. The
minimum and maximum values presented for each pollutant were obtained from the Source File for
both subcategories. The Source File reports the facility average for each pollutant in a subcategory,
and contains many pollutants which were detected at least once in a subcategory but were not
necessarily selected as pollutants of interest.
Certain classical nonconventional pollutants often are grouped with conventional pollutants (as
defined by the Clean Water Act) for the purposes of raw wastewater characterization. These
pollutant parameters include: ammonia as nitrogen, nitrate/nitrite, total dissolved solids, total organic
carbon, total phenols, chemical oxygen demand, amenable cyanide, and total phosphorus. All of these
pollutants are pollutants of interest with the exception of total phosphorus. For the purposes of
presenting raw wastewater characterization data, these nonconventional pollutants have been included
with the conventional pollutants for each landfill subcategory in Table 6-9.
6.3.5 Toxic Pollutants and Remaining Nonconventional Pollutants
Table 6-10 presents the metals data for raw wastewaters from the two subcategories: Non-Hazardous
and Hazardous. A wide range of metals were detected in raw wastewaters from landfill facilities in
both subcategories including both toxic pollutant and nonconventional pollutant metals.
Table 6-11 presents the organic toxic and nonconventional pollutant data for the two subcategories.
A wide range of organic pollutants were detected in raw wastewaters at landfill facilities in the Non-
Hazardous and Hazardous subcategories. Many of these are common organic pollutants found in
municipal or commercial waste.
6-19
-------
6.3.6 Raw Wastewater at Subtitle D Non-Hazardous Landfills
6.3.6.1 Raw Wastewater at Subtitle D Non-Hazardous Landfills: Municipal
Raw wastewater generated at Subtitle D municipal landfills contained a range of conventional, toxic,
and nonconventional pollutants. These wastewaters also contained significant concentrations of
common nonconventional metals such as iron, magnesium, and manganese. These rnetals are
naturally occurring elements found in raw water, and the presence of these metals in landfill raw
wastewater can be attributed to background levels in the water source used at the facility. Any
change between the influent and effluent concentrations of these metals are impacted by the addition
of treatment chemicals that contain these metals and, therefore, were not considered as pollutants of
interest Generally, concentrations of toxic heavy metals were found at relatively low concentrations.
EPA did not find toxic metals such as arsenic, cadmium, mercury, and lead at treatable levels in any
of EPA's sampling episodes. Typical organic pollutants found in leachate included 2-butanone
(methyl ethyl ketone) and 2-propanone (acetone) which are common solvents used in household
products (such as paints and nail polish) and common industrial solvents such 4-methy 1-2-pentanone
and 1,4-dioxane. Trace concentrations of only a few pesticides were detected in wastewaters from
municipal landfills. Additionally, the wastewater was characterized by high loads of organic acids such
as benzoic acid and hexanoic acid resulting from anaerobic decomposition of solid waste.
EPA identified 32 pollutants of interest for Subtitle D municipal landfills including: eight
conventional/nonconventional pollutants, six metals, 16 organics and pesticides/herbicides, and two
dioxins/furans. Three hundred and sixteen pollutants were never detected in EPA sampling episodes,
and approximately 122 pollutants were detected but were not considered to be above the minimum
level.
6.3.6.2 Raw Wastewater at Subtitle D Non-Hazardous Landfills: Non-Municipal
A subset of the Subtitle D Non-Hazardous landfill subcategory is Subtitle D non-municipal. These
types of landfills do not accept typical municipal solid waste or household refuse; rather, these
facilities accept a number of different types of non-hazardous, non-municipal solid wastes. Waste
6-20
-------
incinerator ash, industrial non-hazardous wastes and sludges, wastewater treatment plant sludge, yard
waste, or construction and demolition (C&D) wastes.
EPA identified 10 pollutants of interest for Subtitle D non-municipal landfills including: eight
conventional/nonconventional pollutants, one metal, and one pesticide/herbicide. Three hundred
twenty-four pollutants were never detected .in EPA sampling episodes, and 136 pollutants were
detected but were not considered to be above the minimum level.
Many non-hazardous non-municipal facilities accept two or more of the non-municipal waste types
discussed above. Certain unique facilities accept only one type of waste and are referred to as
"monofills". Because of the unique nature of these monofills, EPA performed an analysis to
determine if significant differences existed in raw wastewater characteristics from Subtitle D
municipal landfills and these monofill facilities. However, characterization and treatment data
collected as part of EPA's sampling episodes focused primarily on the more" prevalent Subtitle D
municipal landfills. To complete this analysis, additional data on raw wastewaters from monofill
facilities were collected from several sources including prior EPA studies (see Chapter 5, Section
5.3.1 for discussion of these studies) and industry supplied data. These data were evaluated to
identify any pollutants found at significant concentrations in monofills which were not found in
Subtitle D municipal landfills.
Based on a review of these data sources, EPA observed that the pollutants present in raw
wastewaters from monofills were not significantly different from those found in Subtitle D municipal
landfills, and, in fact, only a subset of Subtitle D municipal landfill pollutants of interest were found
in raw wastewaters from these monofill facilities. In addition, concentrations of virtually all pollutants
found in ash, sludge, and C&D waste monofills were significantly lower than those found in raw
wastewaters from Subtitle D municipal landfills (see Table 5-1, Chapter 5). As discussed in Chapter
11, EPA proposes to establish equivalent effluent limitations for all Subtitle D non-hazardous
landfills.
6-21
-------
6.3.6.3 Dioxins and Furans in Raw Wastewater at Subtitle D Non-Hazardous Landfills
There are 210 isomers of chlorinated dibenzo-p-dioxins (CDD) and chlorinated dibenzofurans (CDF).
EPA is primarily concerned with the 2,3,7,8-substituted congeners, of which 2,3,7,8-TCDD is
considered to be the most toxic and is the only one that is a toxic pollutant. Non 2,3,7,8-substituted
congeners are considered less toxic in part, because they are not readily absorbed by living organisms.
Dioxins and furans may be formed as by-products in certain industrial unit operations related to
petroleum refining, pesticide and herbicide production, paper bleaching, and production of materials
involving chlorinated compounds. Dioxins and furans are not water-soluble and are not expected
to leach out of non-hazardous landfills in significant quantities.
As part of EPA sampling episodes at 13 non-hazardous landfills, raw wastewater samples were
collected, and a total of 17 congeners of dioxins and furans were analyzed. The results of the data
analyses are presented in Table 6-12. Additional raw leachate data from previous EPA studies (see
Chapter 5, Section 5.3.1) were analyzed from ash monofills. EPA found low levels of OCDD,
HpCDD, and HxCDD in raw wastewaters at several landfills. The most toxic dioxin congener,
2,3,7,8-TCDD, was never detected in raw wastewater at a Subtitle D landfills. All concentrations
of dioxins and furans in raw, untreated wastewater were well below the Universal Treatment
Standards proposed for FO39 wastes (multi-source leachate) in 40 CFR 268.1, which establish
minimum concentration standards based on an acceptable level of risk. At the concentrations found
in raw landfill wastewaters, dioxins and furans are expected to partition to the biological sludge as
part of the proposed BPT/BAT treatment technologies. Partitioning of dioxins and furans to the
sludge was included in the evaluation of treatment benefits and water quality impacts. EPA sampling
data and calculations conclude that the concentrations of dioxins and furans present in the wastewater
would not prevent the sludge from being redeposited in a non-hazardous landfill.
6-22
-------
6.3.7 Raw Wastewater at Subtitle C Hazardous Landfills
Raw wastewaters from Subtitle C hazardous landfills also were characterized through EPA sampling
episodes and industry supplied data obtained through the Detailed Questionnaires. Wastewater
generated at Subtitle C landfills contained a wide range of conventional, toxic, and nonconventional
pollutants at treatable levels. There was a significant increase in the number of pollutants found in
raw wastewaters at hazardous landfills compared to non-hazardous landfills. Pollutants which were
common to both untreated non-hazardous and hazardous wastewaters were generally an order of
magnitude higher in hazardous landfill wastewater. The list of pollutants of interest for the
Hazardous subcategory (presented in Table 6-8), which includes 63 parameters, reflects the more
toxic nature of hazardous landfill wastewater and the wide range of industrial waste sources.
Pollutants typical of raw leachate from hazardous facilities included higher levels of arsenic,
chromium, copper, nickel, and zinc than those concentrations found at Subtitle D facilities.
Cadmium, lead, and mercury were not detected at treatable concentrations in the raw wastewater for
any of the hazardous landfills sampled during EPA sampling episodes.
EPA identified a total of 63 pollutants of interest for Subtitle C hazardous landfills including: 11
conventional/nonconventional pollutants, 11 metals, 37 organics and pesticides/herbicides, and four
dioxins/furans. Two hundred fifty pollutants were never detected in EPA sampling episodes, and
approximately 157 pollutants were detected but were not considered to be present at above the
minimum level.
6.3.7.1 Dioxins and Furans in Raw Wastewater at Subtitle C Hazardous Landfills
As part of EPA sampling episodes at two in-scope Subtitle C landfills and two in-scope pre-1980
industrial landfills, raw leachate samples were collected, and a total of 17 congeners of dioxins and
furans were analyzed. The results of these analyses are presented in Table 6-13. Again, EPA did not
detect the most toxic dioxin congener, 2,3,7,8-TCDD, at an in-scope hazardous/industrial landfill.
EPA found low levels of several congeners in raw wastewaters at many of the sampled landfills. Low
6-23
-------
levels of OCDD, OCDF, HpCDD, and HpCDF were detected in over half of the landfills sampled.
However, all concentrations of dioxins and furans hi raw, untreated waste water were well below the
Universal Treatment Standards proposed for F039 wastes (multi-source leachate) in 40 CFR 268.1,
which establish minimum concentration standards based on an acceptable level of risk. At the
concentrations found in raw landfill wastewaters, dioxins and furans are expected to partition to the
biological sludge as part of the proposed BPT/BAT/PSES treatment technologies. Partitioning of
dioxins and furans to the sludge was included in the evaluation of treatment benefits and water quality
impacts.
6-24
-------
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Table 6-3: Contaminant Concentration Ranges in Municipal Leachate as Reported in Literature Sources
Pollutant
Parameter
Conventional
BOD
PH
TSS
Non-Conventional
Alkalinity
Bicarbonate
Chlorides
COD
Fluorides
Hardness
NH3-Nitrogcn
NO3-Nitrogcn
Organic Nitrogen
Ortho-Phosphorus
Sulfatcs
Sulfidc
TOC
TDS
Total-K-Nitrogcn
Total Phosphorus
Total Solids
Metals
Aluminum
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Total Chromium
Copper
Cyanide
Iron
Lead
Magnesium
Manganese
Mercury
Molybcndum
Nickel
Potassium
Sodium
Titanium
Vanadium
Zinc
George
(1972)
9 - 54,610
3.7 - 8.5
6 - 2,685
0 - 20,850
34 - 2,800
0 - 89,520
0 - 22,800
0 - 1,106
0 - 1,300
1 - 1,826
0 - 42,276
0 - 1,416
1 - 154
5 - 4,080
0 - 9.9
0.2 - 5,500
0 - 0.5
16.5 - 15,600
0.06 - 1,400
2.8 - 3,770
0 - 7,700
0 - 1,000
Chain/DeWalle
(1977)
81 - 33,360
3.7 - 8.5
10 - 700
0 - 20,850
4.7 - 2,467
40 - 89,520
0 - 22,800
0 - 1,106
0.2 - 1,0.29
6.5 - 85
1 - 1,558
256 - 28,000
584 - 44,900
0 - 130
0 - 59,200
0.03 - 17
60 - 7,200
0 - 9.9
0 - 2,820
<0.10 - 2.0
17 - 15,600
0.09 - 125
28 - 3,770
0 - 7,700
0 - 370
Metry/Cross
(1977)
2,200 - 720,000
3.7 - 8.5
13 - 26,500
310 - 9,500
3,260 - 5,730
47 - 2,350
800 - 750,000
35 - 8,700
0.2 - 845
4.5 - 18
2.4 - 550
0.3 - 136
20 - 1,370
100 - 51,000
240 - 2,570
0.12 - 1,700
64 - 547
13
28 - 3,800
85 - 3,800
0.03 - 135
Cameron
(1978)
9 - 55,000
3.7 - 8.5
0 - 20,900
34 - 2,800
0 - 9,000
0-2.13
0 - 22,800
0 - 1,106
0-154
0 - 1,826
0 - 0.13
0 - 42,300
0 - 122
0 - 11.6
0 -5.4
0-0.3
0.3 - 73
0 -0.19
5 - 4,000
0 - 33.4
0 - 10
0 -0.11
0.2 -5,500
0-5.0
16.5 - 15,600
' 0.06 - 1,400
0 - 0.064
0 - 0.52
0.01 - 0.8
2.8 - 3,770
0 - 7,700
0 -5.0
0 - 1.4
0 - 1,000
Wisconsin Report
(20 Sites)
ND - 195,000
5 - 8.9
2 - 140,900
ND - 15,050
2 - 11,375
6.6 - 97,900
0 - 0.74
52 - 225,000
ND - 1,850
ND - 30,500
584 - 50,430
2 - 3,320
ND - 234
ND - 85
ND - 70.2
ND - 12.5
ND - 0.36
0.867 - 13
ND - 0.04
200 - 2,500
ND - 5.6
ND - 4.06
ND - 6
ND - 1,500
0 - 14.2
ND - 780
ND - 31.1
ND - 0.01
0.01 -' 1.43
ND - 7.5
ND - 2,800
12 - 6,010
<0.01
0.01
ND - 731
Sobotka Report
(44 Sites)
7 - 21,600
5.4 - 8.0
28 - 2,835
0 - 7,375
120 - 5,475
440 - 50,450
0.12 - 0.790
0.8 - 9,380
11.3 - 1,200
0 - 5,0.95
4.5 - 78.2
8 -500
5 - 6,884
1,400 - 16,120
47.3 - 938
1,900 - 25,873
0.010 - 5.07
0 - 0.08
0.01 - 10
0.001 - 0.01
0 -0.1
95.5 - 2,100
0.001 - 1.0
0.003 - 0.32
0 -4.0
0.22 - 1,400
0.001 - 1.11
76 - 927
0.03 - 43
0 - 0.02
0.01 - 1.25
30 - 1,375
0.01 - 67
AH concentrations in mg/1, except pH (std units).
ND^Non-detect
6-30
-------
Table 6-4: Landfill Gas Condensate (from Detailed Questionnaire)
QID
16012
16015
Pollutant
Conventional
Oil & Grease
Metals
Arsenic
Organics
1,2-Benzenedicarboxylic Acid, Diethyl Ester
1 ,3 -Butadiene, 1 , 1 ,2,3 ,4,4-Hexachloro-
1 ,3-Dichlorobenzene
1 ,4-Dichlorobenzene
2,4,6-Trichlorophenol
2,4-Dichlorophenol
2,4-Dimethylphenol
2,6-Dinitrotoluene
2-Methyl-4,6-Dinitrophenol
2-Nitrophenol
3,4-Benzopyrene .
3-Methyl-4-Chlorophenol
Benz(E)Acephenenthrylene
Benzenamine, 4-Nitro-
Benzene, Nitro-
Benzene Hexachloride
Benzene, Ethyl-
Benzene, Methyl-
Benzo(Def)Phenanthrene
Bis(2-Chloroethoxy)Methane
Chloroform
Di-n-propyl Nitrosamine
Ethene, Trichloro
Ethene, Tetrachloro-
O-Chlorophenol
Residue, Non-flammable
Metals
Gold
Lead
Zinc
#Obs
1
1
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
- 3
3
3
3
#ND
0
0
1
1
1
1
2
2
2
2
0
2 .
2
1
2
1
2
1
2
2
1
2
2
0
2
1
2
0
1
2
0
Avg. Cone.
422
570
2.0
2.2
1.2
2.0
15.0
15.0
17.3
5.83
100
17.5
2.0
20.0
2.33
2.2
4.3
2.3
3.4
2.6
2.2
2.8
3.9
3.3
2.5
10.6
8.7
27.2
0.04
0.13
0.14
Unit
mg/1
ug/1
mg/1
mnr/|
& *
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
16012: Treated effluent after hydrocarbon/aqueous phase separation and caustic neutralization.
16015: Treated effluent after equalization, caustic neutralization, and carbon adsorption.
QID: Questionnaire ID number
#Obs: Number of observations
#ND: Number of non-detects
6-31
-------
Table 6-5 Epa Sar
POLLUTANT
CLASSSICAL WET CHEMISTRY
AMENABLE CYANIDE
AMMONIA NITROGEN
BOD
CHLORIDE
COD
FLUORIDE
HEXANE EXTRACTABLE MATERIAL
HEXAVALENT CHROMIUM
NITRATE/NITRITE
PH
RECOVERABLE OIL AND GREASE
TDS
TOC
TOTAL CYANIDE
TOTAL PHENOLS
TOTAL PHOSPHORUS
TOTAL SOLIDS
TOTAL SULFIDE
TSS
1613: DIOXINS/FURANS "
2378-TCDD
2378-TCDF
12378-PECDD
12378-PECDF
23478-PECDF
123478-HXCDD
123678-HXCDD
123789-HXCDD
123478-HXCDF
123678-HXCDF
123789-HXCDF
234678-HXCDF
1234678-HPCDD
1234678-HPCDF
1234789-HPCDF
OCDD
OCDF
1657: PESTICIDES/HERBICIDES
AZINPHOS ETHYL
AZINPHOS METHYL
CHLORFEVINPHOS
CHLORPYRIFOS
COUMAPHOS
CROTOXYPHOS
DEF
DEMETONA
DEMETONB
DIAZINON
DICHLORFENTHION
DICHLORVOS
DICROTOPHOS
DIMETHOATE
DIOXATHION
DISULFOTON
EPN
ETHION
ETHOPROP
FAMPHUR
FENSULFOTHION
FENTHION
HEXAMETHYLPHOSPHORAMIDE
LEPTOPHOS
MALATHION
MERPHOS
npling Episode F
CAS MUM
C-025
7664-41-7
C-002
16887-00-6
C-004
16984-48-8
C-036
18540-29-9
C-005
C-006
C-007
C-010
C-012
57-12-5
C-020
14265-44-2
C-008
18496-25-8
C-009
1746-01-6
51207-31-9
40321-76-4
57117-41-6
57117-31-4
39227-28-6
57653-85-7
19408-74-3
70648-26-9
57117-44-9
72918-21-9
60851-34-5
35822-46-9
67562-39-4
55673-89-7
3268-87-9
39001-02-0
2642-71-9
86-50-0
470-90-6
2921-88-2
56-72-4
7700-17-6
78-48-8
8065-48-3A
8065-48-3B
333-41-5
97-17-6
62-73-7
141-66-2
60-51-5
78-34-2
298-04-4
2104-64-5
563-12-2
13194-48-8
52-85-7
115-90-2
55-38-9
680-31-9
21609-90-5
121-75-5
150-50-5
6-32
ollutants Analyzed
POLLUTANT
1657: PESTICIDES/HERBICIDES
MONOCROTOPHOS
NALED
PARATHION (ETHYL)
PRORATE
PHOSMET
PHOSPHAMIDONE
PHOSPHAMIDONZ
RONNEL
SULFOTEPP
SULPROFOS
TEPP
TERBUFOS
TETRACHLORVTNPHOS
TOKUTHION
TRICHLORFON
TRICHLORONATE
TRICRESYLPHOSPHATE
TRIMETHYLPHOSPHATE
1656: PESTICIDES/HERBICIDES
ACEPHATE
ACIFLUOKFEN
ALACHLOR
ALDRIN
ATRAZINE
BENFLURALIN
ALPHA-BHC
BETA-BHC
GAMMA-BHC
DELTA-BHC
BROMACIL
BROMOXYNIL OCTANOATE
BUTACHLOR
CAPTAFOL
CAPTAN
CARBOPHENOTHION
ALPHA-CHLORDANE
GAMMA-CHLORDANE
CHLOROBENZILATE
CHLORONEB
CHLOROPROPYLATE
CHLOROTHALONIL
DIBROMOCHLOROPROPANE
DACTHAL (DCPA)
4,4'-DDD
4,4'-DDE
4,4'-DDT
DIALLATEA
DIALLATEB
DICHLONE
DICOFOL
DIELDRIN
ENDOSULFAN I
ENDOSULFANII
ENDOSULFAN SULFATE
ENDRIN
ENDRIN ALDEHYDE
ENDRIN KETONE
ETHALFLURALIN
ETRADIAZOLE
FENARIMOL
HEPTACHLOR
HEPTACHLOR EPOXIDE
ISODRIN
ISOPROPALIN
CASNUM
6923-22-4
300-76-5
56-38-2
298-02-2
732-11-6
297-99-4
23783-98-4
299-84-3
3689-24-5
35400-43-2
107-49-3
13071-79-9
22248-79-9
34643-46-4
52-68-6
327-98-0
78-30-8
512-56-1
30560-19-1
50594-66-6
15972-60-8
309-00-2
1912-24-9
1861-40-1
319-84-6
319-85-7
58-89-9
319-86-8
314-40-9
1689-99-2
23184-66-9
2425-06-1
133-06-2
786-19-6
5103-71-9
5103-74-2
510-15-6
2675-77-6
5836-10-2
1897-45-6
96-12-8
1861-32-1
72-54-8
72-55-9
50-29-3
2303-16-4A
2303-16-4B
117-80-6
115-32-2
60-57-1
959-98-8
33213-65-9
1031-07-8
72-20-8
7421-93-4
53494-70-5
55283-68-6
2593-15-9
60168-88-9
76-44-8
1024-57-3
465-73-6
33820-53-0
-------
Table 6-5 Epa Sampling
POLLUTANT
1656: PESTICIDES/HERBICIDES
KEPONE
METHOXYCHLOR
METREBUZIN
MffiEX
NITROFEN
NORFLUORAZON
PCS- 10 16
PCB-1221
PCB-1232
PCB-1242
PCS- 1248
PCB-1254
PCB-1260
PENTACHLORONITROBENZENE
PENDAMETHALIN
CIS-PERMETHRIN
TRANS-PERMETHRIN
PERTHANE
PROPACHLOR
PROPANIL
PROPAZINE
SIMAZINE
STROBANE
TERBACIL
TERBUTHYLAZINE
TOXAPHENE
TRIADIMEFON
TRIFLURALIN
1658: PESTICIDES/HERBICIDES
DALAPON
DICAMBA
DICHLOROPROP
DINOSEB
MCPA
MCPP
PICLORAM
2,4-D
2,4-DB
2,4,5-T
2,4,5-TP
1620: METALS
ALUMINUM
ANTIMONY
ARSENIC
BARIUM
BERYLLIUM
BISMUTH
BORON
CADMIUM
CALCIUM
CERIUM
CHROMIUM
COBALT
COPPER
DYSPROSIUM
ERBIUM
EUROPIUM
GADOLINIUM
GALLIUM
GERMANIUM
GOLD
HAFNIUM
HOLMIUM
INDIUM
Episode Polluta
CASNUM
143-50-0
72-43-5
21087-64-9
2385-85-5
1836-75-5
27314-13-2
12674-11-2
11104-28-2
11141-16-5
53469-21-9
12672-29-6
11097-69-1 .
11096-82-5
82-68-8
40487-42-1
61949-76-6
61949-77-7
72-56-0
1918-16-7
709-98-8
139-40-2
122-34-9
8001-50-1
5902-51-2
5915-41-3
8001-35-2
43121-43-3
1582-09-8
75-99-0
1918-00-9
120-36-5
88-85-7
94-74-6
7085-19-0
1918-02-1
94-75-7
94-82-6
93-76-5
93-72-1
7429-90-5
7440-36-0
7440-38-2
7440-39-3
7440-41-7
7440,69-9
7440-42-8
7440-43-9
7440-70-2
7440-45-1
7440-47-3
7440-48-4
7440-50-8
7429-91-6
7440-52-0
7440-53-1
7440-54-2
7440-55-3
7440-56-4
7440-57-5
7440-58-6
7440-60-0
7440-74-6
6-33
its Anajyzed (Cor
POLLUTANT
1620: METALS
IODINE
IRIDIUM
IRON
LANTHANUM
LEAD
LITHIUM
LUTETIUM '
MAGNESIUM
MANGANESE
MERCURY
MOLYBDENUM
MEODYMIUM
NICKEL
NIOBIUM
OSMIUM
PALLADIUM
PHOSPHORUS
PLATINUM
DOTASSIUM
PRASEODYMIUM
RHENIUM
RHODIUM
RUTHENIUM
SAMARIUM
SCANDIUM
SELENIUM
SILICON
SILVER
SODIUM
STRONTIUM
SULFUR
TANTALUM
TELLURIUM
TERBIUM
THALLIUM
THORIUM
THULIUM
TIN
TITANIUM
TUNGSTEN
URANIUM
VANADIUM
YTTERBIUM
YTTRIUM
ZINC
ZIRCONIUM
tinued)
CASNUM
7553-56-2
7439-88-5
7439-89-6
7439-91-0
7439-92-1
7439-93-2
7439.94.3
7439-95-4
7439-96-5
7439.97.6
7439-98-7
7440-00-8
7440-02-0
7440-03-1
7440-04-2
7440-05-3
7723-14-0
7440-06-4
7440-09-7
7440-10-0
7440-15-5
7440-16-6
7440-18-8
7440-19-9
7440-20-2
7782-49-2
7440-21-3
7440-22-4.
7440-23-5
7440-24-6
7704-34-9
7440-25-7
13494-80-9
7440-27-9
7440-28-0
7440-29-1
7440-30-4
7440-31-5
7440-32-6
7440-33-7
7440-61-1
7440-62-2
7440-64-4
7440-65-5
7440-66-6
7440-67-7
-------
Table 6-5 Epa Sampling Epi
POLLUTANT
1624: VOLATILE ORGANICS
.1-DICHLOROETHANE
,1-DICHLOROETHENE
.1 ,1-TRICHLOROETHANE
.1.1 ,2-TETRACHLOROETHANE
1 ,2-TRICHLOROETHANE
,1.2,2-TETRACHLOROETHANE
I.2-D1BROMOETHANE
1 ,2-DICHLOROETHANE
1 3-DICHLOROPROPANE
I .2.3-TRICHLOROPROPANE
1 ,3-DICHLOROPROPANE
1.4-DIOXANE
2-BUTANONEfMEK)
2-CHLORO-U-BUTADIENE
2-CHLOROETHYLVINYL ETHER
2-HEXANONE
2-METHYL-2-PROPENENITRILE
2-PROPANONE ( ACETONE)
2-PROPENAL f ACROLEIN)
2-PROPEN-l-OL (ALLYL ALCOHOL)
3-CHLOROPROPENE
4.METHYL-2-PENTANONE
ACRYLON1TR1LE
BENZENE
BROMODICHLOROMETHANE
BROMOFORM
BROMOMETHANE
CARBON DISULFIDE
CHLOROACETONITRILE
CHLOROBENZENE
CHLOROETHANE
CHLOROFORM
CHLOROMETHANE
CIS- 1 ,3-DICHLOROPROPENE
CROTONALDEHYDE
DI BROMOCHLOROMETHANE
DIBROMOMETHANE
DIETHYL ETHER
ETHYL BENZENE
ETHYL CYANIDE
ETHYL METHACRYLATE
IODOMETHANE
ISOBUTYL ALCOHOL
METHYLENE CHLORIDE
M-XYLENE
O+PXYLENE
TETRACHLOROETHENE
TETRACHLOROMETHANE
TOLUENE
TRANS-1 ,2-DICHLOROETHENE
TRANS- 1 ,3-DICHLOROPROPENE
TRANS- 1 .4-DICHLORO-2-BUTENE
TRICHLOROETHENE
TRICHLOROFLUOROMETHANE
VINYL ACETATE
VINYL CHLORIDE
>ode Poll
CAS MUM
75-34-3
75-35-4
71-55-6
630-20-6
79-00-5
79-34-5
106-93-4
107-06-2
78-87-5
96-18-4
142-28-9
123-91-1
78-93-3
126-99-8
110-75-8
591-78-6
126-98-7
67-64-1
107-02-8
107-18-6
107-05-1
108-10-1
107-13-1
71-43-2
75-27-4
75-25-2
74-83-9
75-15-0
107-14-2
108-90-7
75-00-3
67-66-3
74-87-3
10061-01-5
4170-30-3
124-48-1
74-95-3
60-29-7
100-41-4
107-12-0
97-63-2
74-88-4
78-83-1
75-09-2
108-38-3
136777-61-2
127-18-4
56-23-5
108-88-3
156-60-5
10061-02-6
1 10-57-6
79-01-6
75-69-4
108-05-4
75-01-4
6-34
jtants Analyzed (Continued)
POLLUTANT
1625: SEMTVOLATILE ORGANICS
1-METHYLFLUORENE
1-METHYLPHENANTHRENE
1-PHENYLNAPHTHALENE
U-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
U:3,4-DIEPOXYBUTANE
1,3-BENZENEDIOL (RESORCINOL)
1 ,3-DICHLORO-2-PROPANOL
1 ,3-DICHLOROBENZENE
1,3,5-TRITHIANE
1 ,4-DICHLOROBENZENE
1,4-DINITROBENZENE
1,4-NAPHTHOOUINONE
1,5-NAPHTHALENEDIAMINE
2-BROMOCHLOROBENZENE
2-CHLORONAPHTHALENE
2-CHLOROPHENOL
2-ISOPROPYLNAPHTHALENE
2-METHYL-4,6-DINITROPHENOL
2-METHYLBENZOTHIOAZOLE
2-METHYLNAPHTHALENE
2-NITROANILINE
2-NITROPHENOL
2-PHENYLNAPHTHALENE
2-PICOLINE
2-(METHYLTHIO)BENZOTHIAZOLE
2,3-BENZOFLUORENE
2,3-DICHLOROANILINE
2,3-DICHLORONITROBENZENE
2,3,4,6-TETRACHLOROPHENOL
2,3,6-TRICHLOROPHENOL
2,4-DIAMINOTOLUENE
2,4-DICHLOROPHENOL
2,4-DIMETHYLPHENOL
2,4-DINITROPHENOL
2,4-DINITROTOLUENE
2,4,5-TRICHLOROPHENOL
2,4,5-TRIMETHYLANILINE
2,4,6-TRICHLOROPHENOL
2,6-DICHLORO-4-NITROANILINE
2,6-DICHLOROPHENOL
2,6-DINITROTOLUENE
2,6-DI-TERT-BUTYL-P-BENZOOUINONE
3-BROMOCHLOROBENZENE
3-CHLORONITROBENZENE
3-METHYLCHOLANTHRENE
3-NITROANILINE '
3,3-DICHLOROBENZIDINE
3,3'-DIMETHOXYBENZIDINE
3,5-DIBROMO-4-HYDROXYBENZONITRlLE
3,6-DIMETHYLPHENANTHRENE
4-AMINOBIPHENYL
4-BROMOPHENYL PHENYL ETHER
4-CHLORO-2-NITROANILINE
4-CHLORO-3-METHYLPHENOL
4-CHLOROANILINE
4-CHLOROPHENYL PHENYL ETHER
4-NITROANILINE
4-NITROBIPHENYL
CASNUM
1730-37-6
832-69-9
605-02-7
96-12-8
95-50-1
122-66-7
87-61-6
634-36-6
120-82-1
95-94-3
1464-53-5
108-46-3
96-23-1
541-73-1
291-21-4
106-46-7
100-25-4
130-15-4
2243-62-1
694-80-4
91-58-7
95-57-8
2027-17-0
534-52-1
120-75-2
91-57-6
88-74-4
88-75-5
612-94-2
109-06-8
615-22-5
243-17-4
608-27-5
3209-22-1
58-90-2
933-75-5
95-80-7
120-83-2
105-67-9
51-28-5
121-14-2
95-95-4
137-17-7
88-06-2
99-30-9
87-65-0
606-20-2
719-22-2
108-37-2
121-73-3
56-49-5
99-09-2
91-94-1
119-90-4
1689-84-5
1576-67-6
92-67-1
101-55-3
89-63-4
59-50-7
106-47-8
7005-72-3
100-01-6
92-93-3
-------
Table 6-5 Epa Sampling E
POLLUTANT
1625: SEMTVOLATILE ORGANICS
4-NITROPHENOL
4,4-METHYLENE-BIS(2-CHLOROANILINE)
4,5-METHYLENE-PHENANTHRENE
5-CHLORO-O-TOLUIDINE
5-NITRO-O-TOLUIDINE
7,12-DIMETHYLBENZ(A)ANTHRACENE
ACENAPHTHENE
ACENAPHTHYLENE
ACETOPHENONE
ALPHA-NAPHTHYLAMINE
ALPHA-TERPINEOL
ANILINE
ANTHRACENE
ARAMITE
BENZANTHRONE
BENZENETfflOL
BENZIDINE
BENZOICACID
BENZO(A)ANTHRACENE
BENZO(A)PYRENE
BENZO(B)FLUORANTHENE
BENZO(GHI)PERYLENE
BENZO(K)FLUORANTHENE
BENZYL ALCOHOL
BETA-NAPHTHYLAMINE
BIPHENYL
BIS(2-CHLOROETHOXY) METHANE
BIS(2-CHLOROETHYL) ETHER
BIS(2-CHLOROISOPROPYL) ETHER
BIS(2-ETHYLHEXYL) PHTHALATE
BUTYL BENZYL PHTHALATE
CARBAZOLE
CHRYSENE
CROTOXYPHOS
DIBENZOFURAN
DIBENZOTfflOPHENE
DIBENZOfA,H)ANTHRACENE
DIETHYL PHTHALATE
DIMETHYL PHTHALATE
DIMETHYL SULFONE
DI-N-BUTYL PHTHALATE
DI-N-OCTYL PHTHALATE
DIPHENYL ETHER
DIPHENYLAMINE
DIPHENYEDISULFIDE
ETHYL METHANESULFONATE
ETHYLENETfflOUREA
ETHYNYLESTRADIOL-3-METHYL ETHER
FLUORANTHENE
FLUORENE
HEXACHLOROBENZENE
HEXACHLOROBUTADIENE
HEXACHLOROCYCLOPENTADIENE
HEXACHLOROETHANE
HEXACHLOROPROPENE
HEXANOICACID
INDENOO ,2,3-CD)PYRENE
ISOPHORONE
ISOSAFROLE
LONGIFOLENE
MALACHITE GREEN
METHAPYRILENE
METHYL METHANESULFONATE
NAPHTHALENE
N-C10(N-DECANE)
>isode Pollu
CAS NUM
100-02-7
101-14-4
203-64-5
95-79-4
99-55-8
57-97-6
83-32-9
208-96-8
98-86-2
134-32-7
98-55-5
62-53-3
120-12-7
140-57-8
82-05-3
108-98-5
92-87-5
65-85-0
56-55-3
50-32-8
205-99-2
191-24-2
207-08-9
100-51-6
91-59-8
92-52-4
111-91-1
111-44-4
108-60-1
117-81-7
85-68-7
86-74^8
218-01-9
7700-17-6
132-64-9
132-65-0
53-70-3
84-66-2
131-11-3
67-71-0
84-74-2
117-84-0
101-84-8
122-39-4
882-33-7
62-50-0
96-45-7
72-33-3
206-44-0
86-73-7
118-74-1
87-68-3
77.47.4
67-72-1
1888-71-7
142-62-1
193-39-5
78-59-1
120-58-1
475-20-7
569-64-2
91-80-5
66-27-3
91-20-3
124-18-5
6-35
tants Analyzed(Continued)
POLLUTANT
1625: SEMTVOLATILE ORGANICS
N-C12 (N-DODECANE)
N-C14 (N-TETRA'DECANE)
N-C16 (N-HEXADECANE)
N-C18 (N-OCTADECANE)
N-C20 (N-EICOSANE)
N-C22 (N-DOCOSANE)
N-C24 (N-TETRACOSANE)
N-C26 (N-HEXACOSANE)
N-C28 (N-OCTACOSANE)
N-C30 (N-TRIACONTANE)
NITROBENZENE
N-NITROSODIETHYLAMINE
N-NITROSODIMETHYLAMINE
N-NITROSODI-N-BUTYLAMINE
N-NITROSODI-N-PROPYLAMNE
SI-NITROSODIPHENYLAMINE
N-NITROSOMETHYL -ETHYLAMINE
N-NITROSOMETHYL-PHENYLAMINE
^-NITROSOMORPHOLINE
ST-C10 (N-DECANE)
N-C12 (N-DODECANE)
M-C14 (N-TETRADECANE)
N-C16 (N-HEXADECANE)
^-C18 (N-OCTADECANE)
ST-C20 (N-EICOSANE)
N-C22 (N-DOCOSANE)
ST-C24 (N-TETRACOSANE)
N-C26 (N-HEXACOSANE)
SI-C28 (N-OCTACOSANE)
N-C30 (N-TRIACONTANE)
NITROBENZENE
N-NITROSODIETHYLAMINE
N-NITROSODIMETHYLAMINE
Sf-NITROSODI-N-BUTYLAMINE
^J-NITROSODI-N-PROPYLAMINE
^-NITROSODIPHENYLAMINE
^-NITROSOMETHYL -ETHYLAMINE
^-NITROSOMETHYL-PHENYLAMINE
N-NITROSOMORPHOLINE
•-I-NITROSOPIPERIDINE
N,N-DIMETHYLFORMAMIDE
O-ANISIDINE
O-CRESOL
O-TOLUIDINE
P-CRESOL
'-CYMENE
P-DIMETHYLAMINO-AZOBENZENE
'ENTACHLOROBENZENE
'ENTACHLOROETHANE
PENTACHLOROPHENOL
PENTAMETHYLBENZENE
'ERYLENE
PHENACETIN
'HENANTHRENE
PHENOL
PHENOTfflAZINE
JRONAMIDE
PYRENE
PYRIDINE
SAFROLE
SOUALENE
STYRENE
THIANAPHTHENE (2,3-BENZOTHIOPHENE)
TfflOACETAMIDE
TfflOXANTHONE
TRIPHENYLENE
TRIPROPYLENEGLYCOLMETHYL ETHER
CAS NUM
1 12-40-3
629-59-4
544-76-3
593-45-3
112-95-8
629-97-0
646-31-1
630-01-3
630-02-4
638-68-6
98-95-3
55-18-5
62-75-9
924-16-3
621-64-7
86-30-6
10595-95-6
614-00-6
59-89-2
124-18-5
1 12-40-3
629-59-4
544-76-3
593-45-3
112-95-8
629-97-0
646-31-1
630-01-3
630-02-4
638-68-6
98-95-3
55-18-5
62-75-9
924-16-3
621-64-7
86-30-6
10595-95-6
614-00-6
59-89-2
100-75-4
68-12-2
90-04-0
95-48-7
95-53-4
106-44-5
99-87-6
60-11-7
608-93-5
76-01-7
87-86-5
700-12-9
198-55-0
62-44-2
85-01-8
108-95-2
92-84-2
23950-58-5
129-00-0
110-86-1
94-59-7
7683-64-9
100-42-5
95-15-8
62-55-5
492-22-8
217-59-4
20324-33-8
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Table 6-7: Subtitle D Non-Hazardous Subcategory Master File
Subtitle D Non-Hazardous
Pollutant of Interest
Subtitle D Municipal
Median Concentration (ug/1)
Subtitle D Non-Municipal
Median Concentration (ug/1)
Conventional
BOD
TSS
Classical (Non-Conventional)
Ammonia as Nitrogen
COD
Hexavalent Chromium
Nitrate/Nitrite
TDS
TOG
Total Phenols
Organic (Toxic & Non-Conventional)
1,4-Dioxane
2-Butanone
2-Propanone
4-Methy 1-2-Pentanone
Alpha-Terpineol
Benzoic Acid
Hexanoic Acid
Methylene Chloride
N,N-Dimethylformamide
O-Cresol
P-Cresol
Phenol
Toluene
Tripropyleneglycol Methyl Ether
Metals (Toxic & Non-Conventional)
Barium
Chromium
Strontium
Titanium
Zinc
Pesticides/Herbicides (Non-Conventional)
Dichloroprop
Disulfoton
MCPA
Dioxins/Furans (Non-Conventional)
1234678-HpCDD
OCDD
209,786
150,000
81,717
1,023,000
64.9
651
2,894,289
376,521
637
10.8
1,768
991
100
123
3,897
5,818
36.8
10
15
75
101
108
197
482
28.2
1,671
63.8
140
6.1
6.1
67,000
20,500
75,000
1,100,000
950
4,850,000
236,000
251
4,615
403
0.00014
0.0018
6-43
-------
Table 6-8: Subtitle C Hazardous Subcategory Raw Wastewater Master File
Subtitle C Hazardous
Pollutant of Interest
Median Cone.
fue/n
Subtitle C Hazardous
Pollutant of Interest
Median Cone.
(us/I)
Conventional
BOD
Hexane Extractable Material
TSS
Classical (Non-Conventional
Amenable Cyanide
Ammonia as Nitrogen
COD
Nitrate/Nitrite
TDS
TOG
Total Phenols
Organics (Toxic & Non-Conventional)
1,1-Dichloroethane
1,4-Dioxane
2,4-DimethyIphenol
2-Butanone
2-Propanone
4-Methyl-2-Pentanone
Alpha-Tcrpineol
Aniline
Benzene
Benzole Acid
Benzyl Alcohol
Dicthyl Ether
Ethylbenzenc
Hcxanoic Acid
Isobutyl Alcohol
Methylene Chloride
M-Xylene
Napthalene
CH-PXylene
0-Cresol
Phenol
Pyridinc
P-Cresol
101,000
35,500
67,655
1,638
8,600
1,199,500
5,500
12,628,750
409,547
25,004
51.5
235
70.3
1,464
2,882
580
91.2
149
98.7
1,001
55
60.8
100
593
19.6
324
41.4
58.8
17.1
61.4
562
61
120
Organics (cont.)
Toluene
Trans-l,2-Dichloroethene
Trichloroethene
Tripropyleneglycol Methyl Ether
Vinyl Chloride
Metals (Toxic & Non-Coventional)
Arsenic
Chromium
Copper
Lithium
Molybdenum
Nickel
Selenium
Strontium
Tin
Titanium
Total Cyanide
Zinc
Pesticides/Herbicides (Non-Coventional)
2,4,5-TP
2,4-D
2,4-DB
Dicamba
Dichloroprop
MCPA
MCPP
Picloram
Terbuthylazine
Dioxins/Furans (Non-Conventional)
1234678-HpCDD
1234678-HpCDF
OCDD
OCDF
347
78.7
250
808
42.7
190
47.8
36.4
830
157
302
20
1500
57.2
36.5
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218
4.1
5.1
18.5
4.9
8.6
383
870
5.8
14.5
0.00018
0.00013
0.00035
0.0019
6-44
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7.0 POLLUTANT PARAMETER SELECTION
7.1 Introduction
EPA reviewed wastewater characterization data presented in Chapter 6 to determine the
conventional, nonconventional, and toxic pollutants that were detected at significant quantities in
landfills wastewaters. These pollutants are classified by EPA into three categories: conventional,
nonconventional and toxic pollutants. Conventional pollutants include BOD5, TSS, oil and grease,
and pH. Toxic pollutants (also called priority pollutants) include selected metals, pesticides and
herbicides, and over 100 organic parameters that cover a comprehensive list of volatile and semi-
volatile compounds. Nonconventional pollutants are any pollutants that do not fall within the specific
conventional and toxic pollutant lists, for example, TOC, COD, chloride, fluoride, ammonia-nitrogen,
nitrate/nitrite, total phenol, and total phosphorous.
EPA is authorized to regulate conventional and toxic pollutants under Sections 304(a)(4) and
301(b)(2)(C) of the Clean Water Act (CWA), respectively. The list of toxic pollutants from Section
307 of the CWA has been expanded from the 65 priority pollutants and classes of pollutants identified
in the Settlement Agreement of NRDC vs Train (reference 54) to include 126 priority pollutants. In
addition, the Agency also may regulate other nonconventional pollutants, taking into account factors
such as treatable amounts, toxicity, analytical methods, frequency of occurrence, use of indicator
pollutants and the pass through of pollutants at publicly owned treatment works (POTWs).
This chapter presents the criteria used for the selection of parameters determined to be pollutants of
interest in the industry and the selection of pollutants for establishing effluent limitations guidelines
and standards.
7.2 Pollutants Considered for Regulation
To characterize landfill wastewaters and to determine the pollutants that could potentially be
discharged in significant amounts, EPA collected wastewater characterization samples at 15 landfill
7-1
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facilities that were analyzed for 470 conventional, toxic and nonconventional pollutants including
metals, organics, pesticides, herbicides, and dioxins and furans. The wastewater characterization
analysis is presented in Chapter 6.
From the original list of 470 analytes, EPA developed a list of pollutants of interest for each
subcategory that reflects the types of pollutants typically found in landfill wastewaters. The pollutants
of interest list provided a basis for calculating pollutant mass loadings for the industry and potential
loading reduction benefits to be achieved from the proposed regulation. The list of pollutants of
interest also served as the basis for selecting pollutants for regulation.
7.3 Selection of Pollutants of Interest
Pollutants of interest for landfill facilities were selected by subcategory using the wastewater
characterization data presented in Chapter 6. Figure 7-1 presents a diagram that illustrates the
procedures used to select pollutants of interest.
The following criteria were used to develop a pollutants of interest list for each subcategory:
1. Any pollutant detected three or more times in the influent at a concentration at or
above 5 times the minimum level at more than one facility was determined to be a
pollutant of interest.
2. For dioxins/furans, any pollutant detected three or more times in the influent at a
concentration above the minimum level at more than one facility was determined to
be a pollutant of interest.
3. Pollutants that are naturally occurring compounds found in soil or groundwater at
landfill facilities or pollutants that are used as treatment chemicals in this industry
were excluded from the pollutants of interest list.
The first criteria established a list of pollutants that were detected at significant concentrations at
more than one facility and therefore, considered to be present at significant concentrations in all
landfill wastewaters.
7-2
-------
The second criteria was used to address dioxins and furans, which are potentially toxic even at low
concentrations. At this stage, EPA selected any dioxin and furan as a pollutant of interest if it was
detected in raw wastewater so tiiat these pollutants could be further evaluated for regulation on a
case-by-case basis.
Pollutants that met the first and second criteria but were naturally occurring compounds found in soil
or groundwater or are found commonly in treatment chemicals were then excluded from the
individual subcategory pollutants of interest list. These compounds include aluminum, boron,
calcium, chloride, fluoride, iron, manganese, magnesium, potassium, silicon, sodium, sulfur, total
phosphorus, and total sulfide.
Tables 7-1 and 7-2 present the final pollutants of interest selected for each subcategory. Non-
Hazardous subcategory pollutants of interest presented in Table 7-1 are subdivided into those
pollutants present at Subtitle D municipal solid waste landfills and those present at Subtitle D non-
municipal solid waste landfills. However, these lists were combined into one pollutant of interest list
for the entire Non-Hazardous landfill subcategory. Only one Non-Hazardous subcategory pollutant
of interest, MCPA, was present at non-municipal solid waste landfills and was not present at
municipal solid waste landfills. Therefore, MCPA was added to the list of pollutants of interest for
the entire Non-Hazardous subcategory. Pollutants of interest in both subcategories include
conventional, nonconventional, and toxic pollutants and include metals, organics, pesticides,
herbicides, and dioxins and furans.
7.4 Development of Pollutant Discharge Loadings
EPA developed estimates of the mass loading of pollutant discharges for the pollutants of interest on
a facility-by-facility basis. The loadings were determined for current discharges and for projected
discharges based on each of the proposed regulatory options. Mass loadings were based on current
discharge concentrations and potential regulated flows at each facility. Pollutant discharge loadings
were calculated using the procedures described below.
7-3
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7.4.1 Development of Current Discharge Concentrations
The current discharge concentration database contains the discharge concentration for each pollutant
of interest at each facility hi each subcategory. Mass loadings were determined by multiplying the
pollutant concentration by the facility-specific regulated wastewater flow. EPA used all available
data obtained during the project including Detailed Questionnaire data, detailed monitoring reports,
and EPA sampling data to determine mass loadings.
In the Detailed Technical and Monitoring Questionnaires, facilities were requested to provide
information on wastewater treatment-in-place and to provide concentration data on treated
wastewater effluent All available information for each facility on effluent wastewater was compiled
using the data conventions discussed in Chapter 4 for raw wastewater. Data were available from the
following sources: EPA sampling activities, the Detailed Technical Questionnaire, and the Detailed
Monitoring Questionnaire. For facilities with multiple effluent sample points, the final effluent
concentration was calculated by taking a flow weighted average of the samples. From this
information, a data file was created that contained one average concentration value for each pollutant
of interest at each facility. The amount of data in the file varied significantly from facility to facility.
Several of the current discharge concentrations were based on of hundreds of sampling data points
obtained through the Detailed Monitoring Questionnaire, while others may have been based on as few
as one sampling data point The Detailed Monitoring Questionnaire data reflects up to three years of
data and is unique to each facility in terms of numbers of parameters analyzed and monitoring
frequency. Additionally, monitoring may have been performed weekly, monthly, or quarterly. For
facilities sampled by EPA, there was information available for all 470 analytes and sampling typically
reflected the daily performance of a system over a five day period.
For facilities with wastewater treatment-in-place, but with either no available effluent data or
incomplete effluent data, a treated effluent average concentration was generated. To develop the
treated effluent average concentration, facilities were grouped by subcategory and then placed in
treatment-in-place groups depending on the type of treatment employed on site. Within a treatment-
in-place group, the treated effluent average concentration result for a pollutant of interest was
7-4
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calculated by taking the median of all weighted source averages for all facilities within the treatment-
in-place group. If there were no data for a particular pollutant within a treatment-in-place group, the
treated effluent average concentration result for a pollutant of interest in a subcategory was calculated
by taking the median of all weighted source averages for all facilities within the entire subcategory.
For facilities with no treatment-in-place, raw wastewater concentrations were used to represent
effluent discharge values. Facility averages were calculated using all available data sources and using
the procedures outlined above. For facilities with no treatment-in-place and with either no influent
data or incomplete influent data, the subcategory median raw wastewater results (see Section 6.3.3
for details on developing the raw wastewater Master File) were used to represent the current
discharge for each pollutant of interest.
In the Hazardous subcategory and for Subtitle D non-municipal solid waste facilities in the Non-
Hazardous subcategory, there were insufficient effluent data to calculate a representative treatment-
in-place or subcategory treated effluent average concentration result for several pollutants of interest.
In the Hazardous subcategory, the treated effluent average concentration was based on data from a
limited number of facilities. Subtitle D non-municipal facilities did not provide adequate data to
calculate current discharge concentration values for a majority of the pollutants of interest in the Non-
Hazardous subcategory. The alternate methodologies developed to calculate representative current
discharge concentration values for both the Hazardous subcategory and for Subtitle D non-municipal
facilities in the Non-Hazardous subcategory are discussed below.
7.4.1.1 Alternate Methodology for Non-Hazardous Subcategory: Subtitle D Non-
Municipal
For Subtitle D non-municipal solid waste facilities in the Non-Hazardous subcategory, the effluent
data from municipal solid waste landfills was used to supplement insufficient non-municipal data.
Due to the similarities in the median raw wastewater concentrations from Subtitle D municipal and
non-municipal facilities, this procedure was determined to be appropriate. Subtitle D municipal and
7-5
-------
non-municipal raw wastewater concentration data are presented in the Non-Hazardous subcategory
Master File in Table 6-7 in Chapter 6.
The procedure employed to calculate current discharge concentrations for Subtitle D non-municipal
solid waste facilities is as follows: 1) use all available non-municipal landfill effluent data, 2) place
non-municipal facilities in municipal facility treatment-in-place groups according to treatment-in-place
employed on-site, and 3) use municipal landfills treatment-in-place treated effluent average
concentration results for each non-municipal facility with insufficient data.
One Non-Hazardous subcategory pollutant of interest, MCPA, was determined to be a pollutant of
interest for non-municipal landfills, but not for municipal landfills and, therefore, treated effluent
average concentration data were not available. In this case, the Master File raw wastewater
concentration for MCPA from non-municipal facilities was considered along with the typical percent
removals for the treatment-in-place groups. Treatment-in-place group removals for MCPA were
estimated using the regulatory treatment option removals. For treatment-in-place groups with either
no regulatory treatment option match or with insufficient data, the National Risk Management
Research Laboratory (NRMRL) treatment database (discussed in Section 4.8.4) was used as a
supplement. If no NRMRL treatment data existed, treatment data for other pollutants within the
same analytical method or similar methods were used. Removals from both the regulatory treatment
options and the NRMRL treatment database then were averaged together to obtain the estimated
removal for each treatment-in-place group. The current discharge concentration then was calculated
by multiplying the Master File raw wastewater result by the estimated treatment-in-place group
percent removal (calculated as described above) and subtracting that value from the Master File
result.
7.4.1.2
Alternate Methodology for the Hazardous Subcategorv
Current discharge concentrations for the facilities in the Hazardous subcategory were estimated using
the long term averages developed for the subcategory (see Chapter 11: Development of Effluent
Limitations and Standards). A current discharge concentration file similar to the one developed for
7-6
-------
municipal solid waste facilities in the Non-Hazardous subcategory could not be developed for
hazardous facilities because of a lack of data. The lack of data was due to the fact that there were
no direct discharging hazardous facilities identified in the EPA database. Therefore, the current
discharge concentrations were modeled on the indirect dischargers in the EPA database as a function
of the expected discharge concentrations after treatment using the long term averages. Industry-
provided effluent data were used whenever available. An approach was developed to estimate the
expected discharge concentration from the installed treatment systems at each facility where data was
not available. These current discharge concentration values were developed as a multiple of the
required effluent concentrations.
Based upon the installed treatment system at the facility, a procedure was created to model the
characteristics of the current discharge concentrations. The current discharge concentration was
estimated as twice the long term average (LTA) for a facility without any biological or chemical
treatment in place. The modeling approach used to develop the current discharge concentration for
the indirect dischargers hi the Hazardous subcategory is presented below.
QID
16017
16041
16087
Treatment-In-Place
Separation and neutralization
Sequencing batch reactors
Equalization, chemical precipitation, primary sedimentation,
activated sludge, and secondary sedimentation
Modeling Scheme
2 x LTAmed
LTA
LTA
For facility 16017, the current discharge concentration value was based upon a function of the
LTAmed. The LTAmed is defined as the median of the long term averages hi the Hazardous
subcategory. The long term averages used hi this subcategory are from BAT facilities 16041 and
16087; therefore, the corresponding long term averages were used for both of these BAT facilities.
7.4.2 Development of Pollutant Mass Loadings
Using the current discharge concentration file discussed above, EPA generated mass loading
estimates for each pollutant of interest by multiply ing the current discharge concentration value by
7-7
-------
the facility's average discharge daily flow rate. This resulted in mass loadings, reported in pounds
per day, for each facility in the database. Mass loadings were calculated to determine the amount of
pollution discharged directly or indirectly to surface waters by landfill facilities and to determine the
amount of pollutants projected to be discharged after implementation of the proposed regulatory
technology. Summaries of pollutant mass loadings for the selected regulatory options are presented
in Chapter 11.
7.5 Assessment of Pollutants of Interest
As indicated above, EPA developed extensive lists of pollutants of interest for this industry. The full
list of pollutants of interest were used to develop pollutant loadings and pollutant reductions as a
result of treatment However, only certain pollutants were selected for regulation. The specific
regulation of every pollutant may not be the most cost-effective approach to developing effluent
limitations guidelines.
The treatment technologies evaluated as the basis of the proposed regulation have been demonstrated
to provide removals for classes of compounds with similar treatability characteristics. Several of the
pollutants of interest in the landfill industry are similar in terms of their chemical structure and
treatability. As a result, the regulation of a set of pollutants within a chemical class ensures that the
treatment technologies will provide adequate control of other pollutants of interest within that class
of compounds.
Based upon this analysis, several pollutants of interest were not selected for regulation in the Non-
Hazardous and Hazardous subcategories because they are represented adequately by another
regulated pollutant or are controlled through regulation of another related parameter, as discussed
in the sections below. In addition, several other pollutants of interest also were not selected for
regulation because inadequate data were available for these pollutants at the facilities selected as the
technology basis of the regulation. The methodology used hi the selection of the BPT/BAT/NSPS
and PSES/PSNS facilities from which the limits are based is described in Chapter 11. At these
selected BPT facilities, several of the pollutants of interest were found at concentrations below
7-8
-------
treatable levels, while others were found at only trace amounts and therefore were not considered
likely to cause toxic effects.
7.6 Selection of Pollutants To Be Regulated for Direct Dischargers
Based upon the data analyses outlined above, EPA developed a list of pollutants to be regulated for
the Hazardous and Non-Hazardous subcategories. Figure 7-2 presents a diagram that illustrates the
procedures used to select pollutants to be regulated. EPA is not proposing to .establish effluent
limitations and standards for all conventional, toxic, and nonconventional pollutants. There may be
constituents present in a specific landfill or type of landfill that are not addressed in the development
of this guideline and which may be of concern to a receiving stream or POTW. Due to the specific
nature of landfill waste at various sites, EPA concludes that Best Professional Judgement (BPJ)
should be used for considering specific wastewater characteristics that may be unique to a particular
landfill and were not identified during the proposed rulemaking process. The following sections
discuss EPA's reasons for not proposing effluent limitations for selected pollutants.
7.6.1 Non-Hazardous Subcategory Pollutants to be Regulated for Direct Dischargers
The proposed list of pollutants to be regulated for the Non-Hazardous subcategory was developed
from the pollutants of interest list for the Non-Hazardous subcategory. The Non-Hazardous
pollutants of interest list combines the pollutants of interest from Subtitle D municipal and non-
municipal solid waste facilities for a total of 33 pollutants of interest. The pollutants chosen to be
regulated were demonstrated to be removed by equalization, biological treatment, and multimedia
filtration. Initially, all 33 pollutants of interest were considered for regulation; however, after a
thorough analysis was conducted, 24 pollutants of interest were not selected for regulation under
BPT/BAT/NSPS for one of the following reasons:
The pollutant (or pollutant parameter) is controlled through the regulation of other pollutants
(or pollutant parameters).
The pollutant (or pollutant parameter) is present in only trace amounts and/or is not likely to
cause toxic effects.
7-9
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• The pollutant (or pollutant parameter) is not present in treatable amounts at the selected BPT
facilities upon which the effluent limitations are based.
The following nine Non-Hazardous subcategory pollutants of interest are pollutants that are
controlled through the regulation of other pollutants:
Nine Pollutants Not Selected for Regulation in the Non-Hazardous Subcategory Because They
Are Controlled Through the Regulation of Other Pollutants
COD
TOC
Total Phenols
Hexanoic Acid
O-Cresol
2-Butanone
2-Propanone
4-Methyl-2-Pentanone •
Tripropyleneglycol Methyl Ether
COD is an alternative method of estimating the oxygen demand of the wastewater; however, BOD5
has been selected for regulation because it is more appropriately controlled by a biological treatment
system. TOC measures all oxidizable organic material in a waste stream, including the organic
chemicals not oxidized (and therefore not detected) in BOD5 and COD tests. TOC is a rapid test for
estimating the total organic carbon in a waste stream. For similar reasons to those for not selecting
COD for regulation, TOC also was not selected for regulation because BOD5 is a more appropriate
control parameter for biological treatment systems. Total phenols is a general, wet chemistry
indicator measurement for phenolic compounds and should be controlled by regulating phenol.
Similarly, hexanoic acid is relatively biodegradable and should be controlled by regulating benzoic
acid. O-cresol is structurally similar to p-cresol and should be controlled by regulating p-cresol. Since
2-butanone, 2-propanone and 4-methyl-2-pentanone have similar treatabiliry characteristics as toluene
in a biological treatment system, these three pollutants should be controlled by regulating toluene.
Tripropyleneglycol methyl ether has similar treatabiliry characteristics as alpha-terpineol in a
biological treatment system and should be controlled by regulating alpha-terpineol.
7-10
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The following ten Non-Hazardous subcategory pollutants of interest are present in only trace amounts
and/or are not likely to cause toxic effects:
Ten Pollutants Not Selected for Regulation in the Non-Hazardous Subcategory Because They
Are Present In Only Trace Amounts And/Or Are Not Likely To Cause Toxic Effects
Nitrate/Nitrite
TDS
N,N-Dimethylfoimamide
1,4-Dioxane
Methylene Chloride
Dichloroprop
Disulfoton
MCPA
1,2,3,4,6,7,8-HpCDD
OCDD
For this industry, nitrate/nitrite is used primarily as a measure of the extent of nitrification that occurs
during the biodegradation process. Typically, levels of nitrate/nitrite found in landfill wastewaters
do not require removal. Removal of nitrate/nitrite can be obtained by specially designed biological
treatment systems (such as nitrification/denitrification systems) that are able to complete the
conversion of nitrate/nitrite to nitrogen gas. Often, removal of nitrate/nitrite is required to address
specific water quality concerns for an individual receiving water (i.e., nutrient problems in the Great
Lakes); however, EPA has determined that the levels of nitrate/nitrite in landfill wastewaters does not
justify regulation on a national level and specific water quality considerations can be addressed by
individual permit writers.
TDS is used primarily as a water quality measurement and not as a pollutant that can be controlled
through biological treatment It often is used as a measurement of the salinity of an ambient water
or a wastewater and often indicates the presence of such naturally occurring salts as sodium, iron, and
magnesium. While it can inhibit biological treatment processes at levels above 10,000 mg/1,
acclimated biological treatment systems can operate successfully with influent TDS concentrations
as high as 76,000 mg/l (reference 55). The median concentration of total dissolved solids in the Non-
7-11
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Hazardous subcategory was only 4,900 mg/1 for non-municipal solid waste landfills and 2,900 mg/1
for municipal solid waste landfills. Therefore, EPA has determined that concentrations of total
dissolved solids found in landfills in the Non-Hazardous subcategory do not justify regulation. Levels
of ryl-dimethylformamide found in landfill wastewaters generally were observed near the analytical
detection limit (median concentration for non-hazardous municipal solid waste landfills was 10 ug/1)
and did not warrant regulation.
Two other pollutants, 1,4-dioxane and methylene chloride, are volatile pollutants that are not
biodegraded during biological treatment, but rather are stripped out of the wastewater into the
atmosphere during the aeration process. While EPA does not recognize the transfer of pollutants from
one medium to another as effective treatment, based on the concentrations of these pollutants in
untreated wastewaters, the Agency believes that the loadings of these pollutants to the atmosphere
will be well below the threshold levels to be established by EPA's Air Programs for air discharges
from wastewater treatment systems and, therefore, is excluding these two pollutants from regulation
because they are not likely to cause toxic effects.
EPA found low levels of dichloroprop; disulfoton; MCPA; 1,2,3,4,6,7,8-HpCDD, and OCDD in raw
wastewaters at several Non-Hazardous subcategory landfills. At the concentrations found, these
pollutants are expected to partition to the biological sludge as part of the proposed BPT/BAT
treatment technologies. EPA sampling data and calculations conclude that the concentrations of these
pollutants present hi the wastewater would not prevent the sludge from being redeposited in a non-
hazardous landfill.
The following five pollutants were not selected for regulation in the Non-Hazardous subcategory
because they are not present at treatable concentrations at those facilities chosen as the basis for the
development of effluent limitations:
7-12
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Five Pollutants Not Selected For Regulation in the Non-Hazardous Subcategory Because They
Are Not Present at Treatable Concentrations at Those Facilities Chosen as the Basis for
Developing Effluent Limitations
Barium
Chromium
Hexavalent Chromium
Strontium
Titanium
These five metals were present in wastewaters at the facilities selected as the basis for
BPT/BAT/NSPS, but EPA has determined that these pollutants are not removed readily by the
selected BPT/BAT/NSPS treatment technology (biological treatment) at the observed concentrations
and should not be regulated. Mean raw wastewater concentrations of these five metals at BPT
facilities ranged from 0.07 mg/1 for chromium and titanium to 2.8 mg/1 for strontium. Percent
removals at these BPT facilities ranged from negative removals for hexavalent chromium and barium,
to low percent removals for strontium (12 percent), to relatively high percent removals for chromium
(46 percent and 57 percent) and titanium (92 percent). While the negative and low percent removals
were observed at BPT facilities with relatively high influent concentrations, the higher percent
removals were observed at BPT facilities with influent concentrations of chromium and titanium
approaching the method detection limit, which raises doubt about the accuracy of these percent
removals. EPA also considered control of these five pollutants by other technologies, but the
observed concentrations were considered well below treatable concentrations for conventional metals
treatment technologies (for example, chemical precipitation).
In conclusion, the following nine pollutants of interest are proposed for regulation in the Non-
Hazardous subcategory:
7-13
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Nine Pollutants Selected for Regulation in the Non-Hazardous Subcategory
BOD5
TSS
Ammonia as Nitrogen
Zinc
Alpha-Terpineol
Benzoic Acid
P-Cresol
Phenol
Toluene
The Agency wishes to note that zinc was selected for regulation in spite of the fact that exclusion
criteria used to eliminate other pollutants of interest apply, at least partially. Zinc has been selected
for regulation in spite of its relatively low untreated wastewater concentration. The median
concentration of zinc found in raw wastewater at municipal solid waste landfills and at non-municipal
solid waste landfills is 0.14 mg/1 and 0.09 mg/1, respectively. Zinc was selected for regulation because
EPA observed incidental removals ranging from 66 percent to 93 percent at the treatment systems
selected for BPT. Additionally, raw wastewater concentrations of zinc were not observed at levels
that would inhibit biological treatment systems (see Chapter 11, Section 11.2.1).
The development of the effluent limitations for each of these pollutants is described in detail in
Chapter 11.
7.6.2 Hazardous Subcategory Pollutants to be Regulated for Direct Dischargers
The preliminary list of pollutants to be regulated for the Hazardous Subcategory was developed from
the Hazardous subcategory pollutants of interest list. The pollutants chosen to be regulated were
demonstrated to be removed by chemical precipitation followed by biological treatment. Initially, all
63 pollutants of interest were considered for regulation; however, after a thorough analysis was
conducted, 48 pollutants of interest were not selected for regulation under BPT/BAT/NSPS for one
of the following reasons:
7-14
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• The pollutant (or pollutant parameter) is controlled through the regulation of other pollutants
(or pollutant parameters).
• The pollutant (or pollutant parameter) is present in only trace amounts and/or is not likely to
cause toxic effects.
The pollutant (or pollutant parameter) is not present in treatable amounts at the selected BPT
facilities upon which the effluent limitations are based.
The following seventeen Hazardous subcategory pollutants of interest were not selected for
regulation because they are controlled through the regulation of other pollutants:
Seventeen Pollutants Not Selected For Regulation in the Hazardous Subcategory Because They
Are Controlled Through the Regulation of Other Pollutants
COD
TOC
Total Phenols
2-Butanone
2-Propanone
2,4-Dimethylphenol
4-Methyl-2-Pentanone
Benzyl Alcohol
Diethyl Ether
Ethylbenzene
Isobutyl Alcohol
Hexanoic Acid
Nickel
M-Xylene
O-Cresol
O+P Xylene
Tripropyleneglycol Methyl Ether
COD is an alternative method of estimating the oxygen demand of the wastewater; however, BOD5
has been selected for regulation because it is more appropriately controlled by a biological treatment
system. TOC measures all oxidizable organic material in a waste stream, including the organic
chemicals not oxidized (and therefore not detected) hi BOD5 and COD tests. TOC is a rapid test for
estimating the total organic carbon in a waste stream. For similar reasons to the rationale for not
7-15
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selecting COD for regulation, TOC was also not selected for regulation because BOD5 is a more
appropriate control parameter for biological treatment systems.
While present in treatable concentrations, EPA did not collect adequate performance data for nickel
at well-operated landfill facilities with the recommended technology basis for the Hazardous
subcategory; however, nickel should be controlled adequately through the regulation of both
chromium and zinc. Total phenols is a general, wet chemistry indicator measurement for phenolic
compounds and should be controlled by regulating phenol. Similarly, 2,4-dimethylphenol has similar
chemical and treatability characteristics to phenol and therefore should also be controlled through the
regulation of phenol. Hexanoic acid, benzyl alcohol, and isobutyl alcohol are relatively biodegradable
and should be controlled by regulating benzoic acid. O-cresol is structurally similar to p-cresol and
should be controlled by regulating p-cresol. M-xylene, o+p-xylene, 2-butanone, 2-propanone, 4-
methyl-2-pentanone, and ethylbenzene have similar treatabiliry characteristics as toluene in a
biological treatment system and should be controlled by regulating toluene. Similarly,
tripropyleneglycol methyl ether and diethyl ether have similar treatability characteristics as alpha-
terpineol in a biological treatment system and should be controlled by regulating alpha-terpineol.
The following twenty-two pollutants of interest were not selected for regulation in the Hazardous
subcategory because they are present in only trace amounts and/or .are not likely to cause toxic
effects:
7-16
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Twenty-Two Pollutants Not Selected for Regulation in the Hazardous Subcategory Because
They Are Present In Only Trace Amounts And/Or Are Not Likely To Cause Toxic Effects
Hexane Extractable Material
Nitrate/Nitrite
TDS
1,1 -Dichloroethane
1,4-Dioxane
Methylene Chloride
Trans-1,2-Dichloroethene
Trichloroethene
Vinyl Chloride
2,4-D
2,4-DB
2,4,5-TP
Dicamba
Dichloroprop
MCPA
MCPP
Picloram
Terbutylazine
1,2,3,4,6,7,8-HpCDD
1,2,3,4,6,7,8-HpCDF
OCDD
OCDF
For this industry, nitrate/nitrite is used primarily as a measure of the extent of nitrification that occurs
during the biodegradation process. Typically, levels of nitrate/nitrite found in landfill wastewaters
do not require removal. Removal of nitrate/nitrite can be obtained by specially designed biological
treatment systems (such as nitrification/denitrification systems) that are able to complete the
conversion of nitrate/nitrite to nitrogen gas. Often, removal of nitrate/nitrite is required to address
specific water quality concerns for an individual receiving water (i.e., nutrient problems in the Great
Lakes); however, EPA has determined that the levels of nitrate/nitrite in landfill wastewaters does not
justify regulation on a national level and specific water quality considerations can be addressed by
individual permit writers.
7-17
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IDS is used primarily as a water quality measurement and not as a pollutant that can be controlled
through biological treatment. It often is used as a measurement of the salinity of an ambient water
or a vvastewater and often indicates the presence of such naturally occurring salts as sodium, iron, and
magnesium. While it can inhibit biological treatment processes at levels above 10,000 mg/1,
acclimated biological treatment systems can operate successfully with influent TDS concentrations
as high as 76,000 mg/1 (reference 55). The median concentration of total dissolved solids was 12,600
mg/1 for landfills in the Hazardous subcategory. Therefore, EPA has determined that concentrations
of total dissolved solids found in landfills in the Hazardous subcategory do not justify regulation
Similarly 9 hexane extractable material is a general, wet chemistry indicator measurement for oil and
grease compounds that generally can be controlled through source reduction and good housekeeping.
Therefore EPA did not select hexane extractable material for regulation.
Six other pollutants, 1,1-dichloroethane, 1,4-dioxane, methylene chloride, trans- 1,2-dichloroethene,
trichloroethene and vinyl chloride, are volatile pollutants that are not biodegraded during biological
treatment, but rather are stripped out of the wastewater into the atmosphere during the aeration
process. While EPA does not recognize the transfer of pollutants from one medium to another as
effective treatment, based on the concentrations of these pollutants in untreated wastewaters, the
Agency believes mat the loadings of these pollutants to the atmosphere will be well below the
threshold levels to be established by EPA's Air Programs for air discharges from wastewater
treatment systems and, therefore, is excluding these six pollutants from regulation because they are
not likely to cause toxic effects.
Low levels of 2,4-D, 2,4-DB, 2,4,5-TP, dicamba, dichloroprop, MCPA, MCPP, picloram,
terbutylazine, 1,2,3,4,6,7,8-HpCDD, 1,2,3,4,6,7,8-HpCDF, OCDD, and OCDF were detected in over
half of the Hazardous subcategory landfills sampled during EPA's sampling program. At the
concentrations found in raw landfill wastewaters, these pollutants are expected to partition to the
biological sludge as part of the proposed BPT/BAT/PSES treatment technologies. EPA sampling
data and calculations conclude that the concentrations of these pollutants present in the untreated
wastewater would not prevent the sludge from being redeposited in a hazardous landfill.
7-18
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The following nine pollutants were not selected for regulation in the Hazardous subcategory because
they are not present at treatable concentrations at those facilities chosen as the basis for developing
effluent limitations:
Nine Pollutants Not Selected for Regulation in the Hazardous Subcategory Because They Are
Not Present at Treatable Concentrations at Those Facilities Chosen as the Basis for Developing
Effluent Limitations
Amenable Cyanide
Copper
Lithium
Molybdenum
Selenium
Strontium
Tin
Titanium
Total Cyanide
While several of these pollutants were found in treatable concentrations at selected BPT facilities, the
Hazardous subcategory median untreated wastewater concentrations for many of these pollutants
were well below treatable concentrations. Median untreated wastewater concentrations of six of the
metals ranged from about 0.02 to 0.06 mg/1 for selenium, copper, titanium, and tin; 0.16 mg/1 for
molybdenum; and 0.8 mg/1 for lithium, which are well below treatable concentrations for conventional
metals precipitation technologies. While median untreated wastewater concentrations for strontium
are estimated at 1.5 mg/1 for the Hazardous subcategory, performance data from a BPT facility shows
only a 12 percent removal of strontium at an influent concentration of 2.8 mg/1.
For total cyanide, the median untreated wastewater concentration for the Hazardous subcategory
has been estimated at 0.05 mg/1, which is well below treatable concentrations for conventional
cyanide destruction technologies. While median untreated wastewater concentrations of amenable
cyanide have been estimated at 1.6 mg/1, EPA believes that the median untreated wastewater
concentration data for total cyanide is more representative of cyanide concentrations in hazardous
7-19
-------
landfill wastewaters than amenable cyanide data, since the Agency has collected much more data on
total cyanide than on amenable cyanide.
Based on these factors, the Agency has concluded that these seven metals plus amenable and total
cyanide were present in untreated landfill wastewaters at concentrations that were too low to be
treated effectively by conventional metals and cyanide treatment technologies (chemical precipitation
and chemical oxidation, respectively) and has decided to exclude them from regulation.
In conclusion, the following 15 pollutants of interest are proposed for regulation under
BPT/BAT/NSPS in the Hazardous subcategory:
Fifteen Pollutants Selected For Regulation In The Hazardous Subcategory
BOD5
TSS
Ammonia as Nitrogen
Arsenic
Chromium
Zinc
Alpha-Terpineol
Aniline
Benzene
Benzoic Acid
Naphthalene
P-Cresol
Phenol
Pyridine
Toluene
The development of the effluent limitations for each of these pollutants is described in detail in
Chapter 11.
7-20
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7.7 Selection of Pollutants to be Regulated for Indirect Dischargers
Section 307(b) of the CWA requires the Agency to promulgate pretreatment standards for existing
sources (PSES) and new sources (PSNS). To establish pretreatment standards, EPA must first
determine whether each BAT pollutant under consideration passes through a POTW, or interferes
with the POTWs operation or sludge disposal practices.
7.7.1 Pass-Through Analysis for Indirect Dischargers
The Agency evaluated POTW pass-through for the landfill pollutants of interest for both
subcategories, listed in Tables 7-1 and 7-2. In determining whether a pollutant is expected to pass
through a POTW, the Agency compared the nation-wide average percentage of a pollutant removed
by well-operated POTWs with secondary treatment to the percentage of a pollutant removed by BAT
treatment systems. A pollutant is determined to "pass through" a POTW when the average
percentage removal achieved by a well-operated POTW (i.e. those meeting, secondary treatment
standards) is less than the percentage removed by the industry's direct dischargers that are using the
proposed BAT technology.
This approach to the definition of pass-through satisfies two competing objectives set by Congress:
1) that wastewater treatment performance for indirect dischargers be equivalent to that for direct
dischargers, and 2) that the treatment capability and performance of the POTW be recognized and
taken into account in regulating the discharge of pollutants from indirect dischargers. Rather than
compare the mass or concentration of pollutants discharged by the POTW with the mass or
concentration of pollutants discharged by a BAT facility, EPA compares the percentage of the
pollutants removed by the BAT treatment system with the POTW removal. EPA takes this approach
because a comparison of mass or concentration of pollutants in a POTW effluent to pollutants in a
BAT facility's effluent would not take into account the mass of pollutants discharged to the POTW
from non-industrial sources, nor the dilution of the pollutants hi the POTW effluent to lower
concentrations from the addition of large amounts of non-industrial wastewater.
7-21
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To establish the performance of well-operated POTWs, EPA used the information provided from
'Tate of Priority Pollutants in Publicly Owned Treatment Works", referred to as the 50-POTW Study,
supplemented by EPA's National Risk Management Research Laboratory's (NRMRL) treatability
database. NRMRL's database was used for those pollutants not found in the 50-POTW study. These
studies were discussed previously in Chapter 4. Because the data collected for evaluating POTW
removals included influent levels of pollutants that were close to the detection limit, the POTW data
were edited to eliminate low influent concentration levels. For analytes that included a combination
of high and low influent concentrations, the data were edited to eliminate all influent values, and
corresponding effluent values, less than 10 times the minimum level. For analytes where no influent
concentrations were greater than 10 times the minimum level, all influent values less than five times
the minimum level and the corresponding effluent values were eliminated. For analytes where no
influent concentration was greater than five times the minimum level, the data were edited to
eliminate all influent concentrations, and corresponding effluent values, less than 20 ug/1. These
editing rules were used to eliminate low POTW removals that simply reflected low influent levels.
The POTW database was further edited so that only treatment technology data for activated sludge,
aerobic lagoons, and activated sludge with filtration were used.
After editing the database according to the above criteria, EPA averaged the remaining influent data
and the remaining effluent data from the 50-POTW database. The percent removals achieved for
each pollutant were determined from these averaged influent and effluent levels. This percent
removal was then compared to the percent removal for the proposed BAT option treatment
technology.
7.7.2 Non-Hazardous Subcategory Pollutants to be Regulated for Indirect Dischargers
EPA conducted a pass-through analysis on the priority and nonconventional pollutants proposed to
be regulated under BAT for hazardous landfills. The pass-through analysis was not performed for
the regulated conventional pollutants, namely BOD5 and TSS, since the conventional pollutants are
not regulated under PSES and PSNS. Of the seven nonconventional and toxic pollutants regulated
under BAT for the Non-Hazardous subcategory, only one pollutant proposed for regulation under
7-22
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BAT, ammonia as nitrogen, appeared to pass through. However, for the reasons discussed in
Chapter 11, EPA is not proposing pretreatment limits for ammonia, or any other pollutant, in the
Non-Hazardous subcategory.
7.7.3 Hazardous Subcategory Pollutants to be Regulated for Indirect Dischargers
EPA conducted a pass-through analysis on the priority and nonconventional pollutants proposed to
be regulated under BAT for hazardous landfills. The pass-through analysis was not performed for
the regulated conventional pollutants, namely BOD5 and TSS, since the conventional pollutants are
not regulated under PSES and PSNS. Of the thirteen nonconventional and toxic pollutants regulated
under BAT for the Hazardous subcategory, seven were determined to pass through. However, EPA
proposes pretreatment standards for only the following six pollutants: ammonia as nitrogen, benzoic
acid, toluene, alpha-terpineol, p-cresol, and aniline. Even though phenol appeared to pass through,
EPA has decided not to set pretreatment standards for phenol. The rationale for not setting
pretreatment standards for phenol can be found in Chapter 11. The list of pollutants regulated under
BAT, the BAT option percent removals, the average POTW percent removals, and the results of the
pass-through analysis for the Hazardous subcategory are shown in Table 7-3. The proposed
pretreatment standards for the Hazardous subcategory are listed in Table 11-12.
Six Pollutants Selected For Regulation For Indirect Dischargers In The Hazardous
Subcategory
Ammonia as Nitrogen
Alpha-Terpineol
Aniline
Benzoic Acid
P-Cresol
Toluene
The development of the pretreatment limitations for each of these pollutants is described in detail in
Chapter 11.
7-23
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Table 7-1: Non-Hazardous Subcategory Pollutants of Interest
Non-Hazardous
Pollutant of Interest
Conventional
BOD
TSS
Nonconventional
Ammonia as Nitrogen
COD
Nitrate/Nitrite
TDS
TOG
Total Phenols
Organic
1,4-Dioxane
2-Butanone
2-Propanone
4-MeUiyl-2-Pentanone
Alpha-Terpineol
Benzoic Acid
Hexanoic Acid
Methylene Chloride
N,N-Dimethylformamide
O-Cresol
P-Cresol
Phenol
Toluene
Tripropyleneglycol Methyl Ether
Metals
Barium
Chromium
Hexavalent Chromium
Strontium
Titanium
Zinc
Pesticides/Herbicides
Dichloroprop
Disulfoton
MCPA
Dioxins/Furans
1234678-HpCDD
OCDD
Cas#
C-002
C-009
7664417
C-004 '
C-005
C-010
C-012
C-020
123911
78933
67641
108101
98555
65850
142621
75092
68122
95487
106445
108952
108883
20324338
7440393
7440473
18540299
7440246
7440326
7440666
120365
298044
94746
35822469
3268879
Subtitle D Municipal
Pollutant of Interest
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X "
X
Subtitle D Non-Municipal
Pollutant of Interest
X
X
X
X
X
X
X
X
X
X
7-24
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Table 7-2: Hazardous Subcategory Pollutants of Interest
Pollutant of Interest
Cas#
Pollutant of Interest
Cas#
Conventional
BOD
Hexane Extractable Material
TSS
Nonconventional
Amenable Cyanide
Ammonia as Nitrogen
COD
Nitrate/Nitrite
TDS
TOC
Total Phenols
Organics
1,1 -Dichloroethane
1,4-Dioxane
2,4-Dimethylphenol
2-Butanone
2-Propanone
4-Methyl-2-Pentanone
Alpha-Terpineol
Aniline
Benzene
Benzoic Acid
Benzyl Alcohol
Diethyl Ether
Ethylbenzene
Hexanoic Acid
Isobutyl Alcohol
Methylene Chloride
M-Xylene
Napthalene
O+PXylene
O-Cresol
Phenol
Pyridine
C-002
C-036
C-009
C-025
7664417
C-004
C-005
C-010
C-012
C-020
75343
123911
105679
78933
67641
108101
98555
62533
71432
65850
100516
60297
100414
142621
78831
75092
108383
91203
136777612
95487
108952
110861
Organics (cont.)
P-Cresol
Toluene
Trans-1,2-Dichloroethene
Trichloroethene
Tripropyleneglycol Methyl Ether
Vinyl Chloride
Metals
Arsenic
Chromium
Copper
Lithium
Molybdenum
Nickel
Selenium
Strontium
Tin
Titanium
Total Cyanide
Zinc
Pesticides/Herbicides
2,4,5-TP
2,4-D
2,4-DB
Dicamba
Dichloroprop
MCPA
MCPP
Picloram
Terbuthylazine
Dioxins/Furans
1234678-HpCDD
1234678-HpCDF
OCDD '
OCDF
106445
108883
156605
79016
20324338
75014
7440382
7440473
7440508
7439932
7439987
7440020
7782492
7440246
7440315
7440326
57125
7440666
93721
94757
94826
1918009
120365
94746
7085190
1918021
5915413
35822469
67562394
3268879
39001020
7-25
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Table 7-3: Pass-Through Analysis for Pollutants to be Regulated in the Hazardous Subcategory
Pollutant
Ammonia
Arsenic
Chromium
Zinc
Alpha Terpineol
Aniline
Benzene
Benzoic Acid
Naphthalene
P-Cresol
Phenol
Pyridine
Toluene
Average BAT
Percent Removal
74%
55%
80%
64%
99%
98%
88%
99%
80%
98%
99%
57%
99%
Average POTW
Percent Removal
60%
66%
82%
81%
95%
62%
95%
82%
95%
68%
95%
95%
96%
Pass-Through
Yes
No
No
No
Yes
Yes
No
Yes
No
.Yes
Yes
No
Yes
7-26
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Figure 7-1: Development of Pollutants of Interest
/ Start with 470 pollutant parameters \
V analyzed in each episode J
Was the
pollutant parameter ever
detected in any
sample?
List of pollutants detected at least once in
any sample:
Non-Hazardous Municipal-154
Non-HazardousNon-Municipal -146
Hazardous-220
Pollutants removed from consideration
because they were never detected in
any sample:
Non-Hazardous Municipal-316
Non-Hazardous Non-Municipal-324
Hazardous-250
Is the pollutant detected three
or more times at a concentration equal to or
greater than five times the minimum level (for dioxins/
furans at a concentration above the minimum level)?
Is the pollutant detected at more than one
in-scope facility (excluding captives)?
s the pollutant a treatment chemical or a naturally
occurring compound in soil or groundwater?
Pollutants removed from consideration
since not detected three or more times at a
concentration equal to or greater than five
times the minimum level:
Non-Hazardous Municipal-102
Non-Hazardous Non-Municipal-123
Hazardous-138
Pollutants removed from consideration
since not detected at more than one
facility:
Non-Hazardous Municipal-6
Non-Hazardous Non-Municipal-0
Hazardous-5
Pollutants removed from consideration
since they were considered treatment
chemicals or naturally occurring
compounds:
Non-Hazardous Municipal-14
Non-Hazardous Non-Municipal-13
Hazardous-14
Remaining pollutants considered pollutants
of interest:
Non-Hazardous Municipal-32
Non-Hazardous Non-Municipal-10
Hazardous-63
7-27
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Figure 7-2: Selection of Pollutants to be Regulated
Remaining pollutants considered pollutant:
of interest:
Non-Hazardous Municipal-32
Non-Hazardous Non-Municipal-10
Combined Non-Hazardous-33
Hazardous-63
Will the pollutant be controlled through the
regulation of other pollutants?
Is the pollutant present in only trace amounts
and /or is not likely to cause toxic effects?
Is the pollutant present at treatable
concentrations at the selected BPT facilities
n which the effluent limitations are bas
Hazardous subcategory
PSES/PSNS options only: Does the pollutant
pass-through a POTW or cause
inhibition or interference?
Pollutants removed from consideration because they were
controlled through the regulation of other pollutants:
Non-Hazardous-COD, TOC, total phenols, hexanoic acid, o-
cresol, 2-butanone, 2-propanone, 4-methyl-2-perAtanone,
tripropyleneglycol methyl ether
I *Hazardous-COD, TOC, total phenols, nickel, 2,4-
dimethylphenol, ethylbenzene, 2-butanone, 2-propanone, 4-
methyl-2-pentanone, benzyl alcohol, diethyl ether, isobutyl
alcohol, hexanoic acid, m-xylene, o+p xylene, o-cresol,
tripropyleneglycol methyl ether
Pollutants removed from consideration because they were present
in only trace amounts and/or were not likely to cause toxic
effects:
Non-Hazardous-nitrate/nitrite, TDS, 1,4-dioxane, methylene
chloride, n,n-dimethylformamide, OCDD, 1234678-HpCDD,
dichloroprop, disulfoton, MCPA
Hazardous-nitrate/nitrite, hexane extractable material, TDS, 1,4-
dioxane, 1,1-dichloroethane, trans-l,2-dichloroethene, methylen
chloride, trichloroethene, vinyl chloride, OCDD, OCDF,
1234678-HpCDD, 1234678-HpCDF, 2,4-DB, dicamba,
dichloroprop, 2,4,5-TP, 2,4-D, MCPA, MCPP, picloram,
terbutylazine
Pollutants removed from consideration because they were not
present at treatable concentrations at the selected BPT facilities:
Non-Hazardous- barium, chromium, hexavalent chromium,
strontium, titanium
Hazardous- amenable cyanide, total cyanide, copper, lithium,
molybdenum, selenium, strontium, tin, titanium,
Pollutants removed from consideration for the Hazardous
subcategory PSES/PSNS
options only because they do not pass-through a POTW or cause
inhibition or interference:
Hazardous-BOD5, TSS, arsenic, chromium, zinc, benzene,
naphthalene, phenol, pyridine
Yes
Pollutants selected for regulation:
Non-Hazardous-ammonia as nitrogen, BOD,, TSS, zinc, alpha-
tcrplneol, benzoic acid, p-cresol, phenol, toluene
Hazardous-ammonia as nitrogen, BOQ *,TSS*, arsenic*, chromium*,
zinc*, alpha-terpineol, aniline, benzene*, benzoic acid, naphthalene*,
p-cresol, phenol*, pyridine*, toluene
*Btcluded from PSES/PNSN options
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8.0 WASTEWATER TREATMENT TECHNOLOGY DESCRIPTION
This chapter consists of two main parts: Section 8.1 describes the wastewater treatment and sludge
handling methods currently in use in the Landfills industry and Section 8.2 presents a discussion on
the performance of treatment systems evaluated by EPA using data collected during engineering site
visits field sampling programs.
8.1
Available BAT and PSES Technologies
The Landfills industry uses a wide variety of technologies for treating wastewater discharges. These
technologies can be classified into the following five areas:
Best Management Practices
Physical/Chemical Treatment
Biological Treatment
Sludge Handling
Zero Discharge options
Section
8.1.1
8.1.2
8.1.3
8.1.4
8.1.5
The EPA's Detailed Technical Questionnaire obtained information on 14 treatment technologies
currently in use hi the Landfills industry. Table 8-1 presents the technologies most commonly used
by in-scope Subtitle D non-hazardous and Subtitle C hazardous landfill facilities by discharge type.
The table reports the percent of landfill facilities which use each treatment technology. In addition,
EPA collected detailed information on available technologies from engineering plant visits to a
number of landfill facilities. The data presented below are based on these data collection efforts.
8.1.1 Best Management Practices
Best management practices with regard to wastewater generation at landfills can be designed to do
one of two things: reduce the volume of leachate produced by the landfill or reduce the toxicity of
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the leachate produced by the landfill. The volume of leachate generated by a landfill is largely
dependent on the annual precipitation that falls within the landfill area, percolates through the
landfilled waste, and collects in the leachate collection system. Closed landfills are required, to install
an impermeable cap over the landfill to prevent infiltration of rainwater, which will eventually reduce
the volume of wastewater produced by the landfill. Open landfills, however, can similarly use
methods to reduce rainwater infiltration to the landfill, and hence reduce wastewater generation. The
open face of the landfill is the active area where solid waste is deposited, compacted, and covered
with daily fill. This area can act as a collection point for rainwater. By maintaining a small open face
on the landfills, along with using impermeable materials on the closed or inactive sections, a landfill
operator can reduce the volume of wastewater collected and produced by an open landfill.
Many municipal solid waste landfills and communities have developed programs to prevent toxic
materials from being deposited in the landfills. Solid waste generated by households may contain
many types of waste which may present an environmental hazard, including paints, pesticides, and
batteries. Many communities have developed household hazardous waste collection programs which
collect and dispose of these hazardous wastes in an appropriate manner, thus avoiding deposition of
hazardous wastes hi the municipal landfill, and reducing the risks associated with the leachate
produced by the landfill.
8.1.2 Physical/Chemical Treatment
8.1.2.1 Equalization
Wastewater and leachate generation rates at landfills are variable due to their direct relationship to
rainfall, storm water run-on and run-off, groundwater entering the waste-containing zone, and the
moisture content and absorption capability of the wastes. To allow for the equalization of pollutant
loadings and flow rates, leachate and other landfill generated wastewaters are often collected prior
to treatment in tanks or ponds with sufficient capacity to hold the peak flows generated at the facility.
A constant flow is delivered from these holding tanks in order to dampen the variation in hydraulic
and pollutant loadings to the wastewater treatment systems. This reduction in hydraulic and pollutant
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variability increases the performance and reliability of down stream treatment systems and can reduce
the size of subsequent treatment by reducing the maximum flow rates and concentrations of
pollutants. Equalization also lowers the operating costs of associated treatment units by reducing
instantaneous treatment capacity demand and by optimizing the amount of treatment chemicals
required for a less erratic set of treatment variables. National estimates based on EPA's Detailed
Questionnaire data show that 23 percent of direct and 11 percent of indirect non-hazardous landfill
facilities use some form of equalization as part of wastewater treatment systems.
Equalization systems consist of steel or fiberglass holding tanks or lined ponds that provide sufficient
capacity to contain peak flow conditions. Detention times are determined using a mass balance
equation and are dependent on site-specific generation rates and treatment design criteria. Data
provided by the Landfills industry in questionnaire responses indicated a range in the design detention
times of influent equalization systems from less than a day to a high of 90 days with a median value
of about two days. A two day detention time is typical of equalization units installed for wastewater
treatment systems at landfill facilities selected as the basis for the proposed effluent limitations
guidelines. Equalization systems can be equipped to contain either mechanical mixing systems or
aeration systems that enhance the equalization process by keeping the tank contents well mixed and
prohibiting the settling of solids.
A breakdown of equalization systems used hi the Landfills industry based on the responses to the
Detailed Questionnaire is as follows:
Equalization Type
Unstirred
Mechanically Stirred
Aerated
% Non-Hazardous Facilities
Direct Indirect
17 6
>1 <1
10 6
% Hazardous Facilities
Indirect
0
0
0
A typical equalization system is shown in Figure 8-1.
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8.1.2.2
Neutralization
Wastewaters generated by landfills may have a wide range of pH depending on the types of waste
deposited in the landfill. In many instances, raw wastewater may require neutralization to eliminate
either high or low pH values prior to treatment systems, such as activated sludge biological treatment.
However, neutralization systems also are used in conjunction with certain chemical treatment
processes, such as chemical precipitation, to adjust the pH of the wastewater to optimize process
control. Acids, such as sulfuric acid or hydrochloric acid, are added to reduce pH, and alkalies, such
as sodium hydroxides, are added to raise pH values. Neutralization may be performed in a holding
tank, rapid mix tank, or an equalization tank. Typically, neutralization systems at the end of a
treatment system are designed to control the pH of the discharge to between 6 and 9. National
estimates based on EPA's Detailed Questionnaire data show that 33 percent of indirect hazardous
landfills, 7 percent of indirect non-hazardous landfills, and 7 percent of direct non-hazardous landfill
facilities employ neutralization as part of wastewater treatment systems using a variety of chemical
additives to control pH.
Figure 8-2 presents a flow diagram for a typical neutralization system.
8.1.2.3
Flocculation
Flocculation is a treatment technology used to enhance sedimentation or filtration treatment system
performance. Flocculation precedes these processes and usually consists of a rapid mix tank, or
in-line mixer, and a flocculation tank. The waste stream is initially mixed while a flocculation
chemical is added. Flocculants adhere readily to suspended solids and each other to facilitate gravity
sedimentation or filtration. Coagulants can be added to reduce the electrostatic surface charges and
enhance the formation of complex hydrous oxides. Coagulation allows for the formation of larger,
heavier particles, or flocculants (which usually occur in a flocculation chamber), that can settle faster.
There are three different types of flocculants commonly used: inorganic electrolytes, natural organic
polymers, and synthetic poly electrolytes. The selection of the specific treatment chemical is highly
dependent upon the characteristics and chemical properties of the contaminants. A rapid mix tank
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is usually designed for a detention time from 15 seconds to several minutes (see reference 3). After
mixing, the coagulated wastewater flows to a flocculation basin where slow mixing of the waste
occurs. The slow mixing allows for the particles to agglomerate into heavier, more settleable solids.
Mixing is provided either by mechanical paddle mixers or by diffused air. Flocculation basins are
typically designed for a detention time of 15 to 60 minutes (see reference 3). Since many landfill
facilities employ gravity assisted separation and chemical precipitation as part of wastewater
treatment systems, EPA assumes that many of these facilities employ flocculation to enhance system
performance. However, data on the use of flocculation at landfill facilities were not collected as part
of the Detailed Questionnaire survey, and, therefore, this cannot be confirmed definitely.
8.1.2.4 Gravity Assisted Separation
Gravity assisted separation or sedimentation is a simple, economical, and widely used method for the
treatment of landfill wastewaters. Clarification systems remove suspended matter, flocculated
impurities, and precipitates from wastewater. By allowing the wastewater to become quiescent, the
suspended matter, which is heavier than water, can settle to the bottom of the clarifier, forming a
sludge blanket which can be removed. This process can occur in specially designed tanks, or in
earthen ponds and basins. Clarification systems can also be equipped to allow for the removal of
materials lighter than water, such as oils, which are skimmed from the surface and collected for
disposal. Sedimentation units at landfills are used as either primary treatment options to remove
suspended solids or following a biological or chemical precipitation process. Sedimentation processes
are highly sensitive to flow fluctuations and, therefore, usually require equalization at facilities with
large flow variations.
Clarifiers can be rectangular, square, or circular in shape. In rectangular or square tanks, wastewater
flows from one end of the tank to the other with settled sludge collected into a hopper located at one
end of the tank. In circular tanks, flow enters from the center and flows towards the outside edge
with sludge collected in a center hopper. Treated wastewater exits the clarifier by flowing over a weir
located at the top of the clarifier. Sludge which accumulates at the bottom of the clarifier is
periodically removed and is typically stabilized and/or dewatered prior to disposal. National estimates
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based onEPA's Detailed Questionnaire data suggest that 67 percent of indirect hazardous landfills,
9 percent of indirect non-hazardous landfills, and 32 percent of direct non-hazardous landfill facilities
employ some form of gravity assisted separation as part of wastewater treatment systems.
Flocculation systems are commonly used in conjunction with gravity assisted clarification systems to
improve their solids removal efficiency. Some clarifiers are designed with a center well to introduce
flocculants and allow for coagulation in order to improve removal efficiencies. A schematic of a
typical clarification system using coagulation and fiocculation is shown in Figure 8-3. The main
design parameters used in designing a clarifier are the overflow rate, detention tune, and the side
water depth. Overflow rate is the measure of the flow as a function of the surface area of the clarifier.
Typical design parameters used for both primary and secondary clarifiers are presented below (see
reference 7):
Design Parameter Primary
Overflow rate, gpd/sq ft 600-1,000
Detention time,min 90-150
Minimum Side water depth, ft 8
Secondary
500-700
90-150
10
A variation of conventional clarification process is the chemically-assisted clarification process.
Coagulants are added to clarifiers to enhance liquid-solid separation, permitting solids denser than
water to settle to the bottom and materials less dense than water (including oil and grease) to flow
to the surface. Settled solids form a sludge at the bottom of the clarifier which can be pumped out
continuously or intermittentiy. Oil and grease and other floating materials may be skimmed.
Chemically assisted clarification may be used alone or as part of a more complex treatment process.
It also may be used as:
• The first process applied to wastewater containing high levels of settleable suspended
solids.
• The second stage of most biological treatment processes to remove the settleable
materials, including microorganisms, from the wastewater; the microorganisms then
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can be either recycled to the biological reactor or sent to the facility's sludge handling
system.
The final stage of most chemical precipitation (coagulation/flocculation) processes to
remove the inorganic floes from the wastewater.
As discussed in Chapter 9, chemically assisted clarification was a component of the model wastewater
treatment technology for estimating the BPT engineering costs of compliance. In developing
regulatory compliance costs, chemically assisted clarification processes were used as an additional
polishing process after biological treatment. Chemically assisted clarification processes consists of
both a clarifier and a polymer feed system. For facilities currently with sedimentation following
biological treatment, additional costs were only provided for a polymer feed system. Chemically
assisted clarification systems were provided to aid in the settling process following biological
treatment to enhance both TSS and BOD5 removals through the wastewater treatment process.
Higher BOD5 removals can be obtained by the additional removal of microbial floe in the clarifier.
Facilities were costed for a chemical assisted clarification system when their current performance for
TSS and/or BOD5 was slightly out of compliance with proposed regulatory levels (up to 10 mg/1 for
BOD5 and 50 mg/1 for TSS). For instance, if a facility had a aerobic lagoon treatment system and
exceeded the regulatory level for TSS by 20 mg/1, the facility was costed for a chemically assisted
clarification system.
Although chemical addition was not reported by landfill facilities, chemically assisted clarification is
a proven technology for the removal of BOD5 and TSS in a variety of industrial categories (see
reference 19).
National estimates indicate that less than one percent of direct and indirect non-hazardous landfills
use an alternative clarification system design based on corrugated plate interceptor (CPI) technology.
These systems include a series of small (approximately two inch square) inclined tubes in the
clarification settling zone.. The suspended matter must only travel a short distance, when settling or
floating, before they reach a surface of the tube. At the tubes' surface, the suspended matter further
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coagulate. Because of the increased surface area provided by the inclined tubes, CPI units can have
much smaller settling chambers than standard clarifiers.
8.1.2.5 Chemical Precipitation
Chemical precipitation is used for the removal of metal compounds from wastewater. In the chemical
precipitation process, soluble metallic ions and certain anions found in landfill wastewaters are
converted to insoluble forms, which precipitate from solution. Most metals are relatively insoluble
as hydroxides, sulfides, or carbonates. Coagulation processes are used in conjunction with
precipitation to facilitate removal by agglomeration of suspended and colloidal materials. The
precipitated metals are subsequently removed from the wastewater stream by liquid filtration or
clarification (or some other form of gravity assisted separation). Other treatment processes such as
equalization, chemical oxidation or reduction (e.g., hexavalent chromium reduction), usually precede
the chemical precipitation process. The performance of the chemical precipitation process is affected
by chemical interactions, temperature, pH, solubility of waste contaminants, and mixing effects.
Common precipitates used at landfills facilities include lime, sodium hydroxide, soda ash, sodium
sulfide, and alum. Other chemicals used in the precipitation process for pH adjustment and/or
coagulation include sulfuric and phosphoric acid, ferric chloride, and polyelectrolytes. Often, facilities
use a combination of these chemicals. Precipitation using sodium hydroxide or lime is the
conventional method of removing metals from wastewater at landfill facilities. Hydroxide
precipitation is effective in removing such metals as antimony, arsenic, chromium, copper, lead,
mercury, nickel, and zinc. However, sulfide precipitation also is used instead of hydroxide
precipitation to remove specific metal ions such as mercury, lead, and silver. Carbonate precipitation
is another method of chemical precipitation and is used primarily to remove antimony and lead. Use
of alum as a precipitant/coagulant agent results in the formation of aluminum hydroxides in
wastewaters containing calcium or magnesium bicarbonate alkalinity. Aluminum hydroxide is an
insoluble gelatinous floe which settles slowly and entraps suspended materials and is effective for
metals such as arsenic and cadmium.
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Since lime is less expensive than caustic, it is more frequently used at landfill facilities employing
hydroxide precipitation. However, lime is more difficult to handle and feed, as it must be slaked,
slurried, and mixed, and can often plug the feed system lines. Lime precipitation also produces a
larger volume of sludge. The reaction mechanism for precipitation of a divalent metal using lime is
shown below:
Ca(OH)2 - M(OH)2
And, the reaction mechanism for precipitation of a divalent metal using sodium hydroxide is:
2NaOH - M(OH)2
In addition to the type of treatment chemical chosen, another important design factor in the chemical
precipitation operation is pH. Metal hydroxides are amphoteric, meaning they can react chemically
as acids or bases. As such, their solubilities increase toward both lower and higher pH levels.
Therefore, there is an optimum pH for precipitation for each metal, which corresponds to its point
of minimum solubility. Figure 8-4 presents calculated solubilities of metal hydroxides. For example,
as demonstrated on this figure, the optimum pH range where zinc is the least soluble is 8 to 10.
Another key consideration in a chemical precipitation application is the detention time in the
sedimentation phase of the process, which is specific to the wastewater being treated and the desired
effluent quality.
The first step of a chemical precipitation process is pH adjustment and the addition of coagulants.
This process usually takes place in separate mixing and flocculation tanks. After mixing the
wastewater with treatment chemicals, the resultant mixture is allowed to agglomerate in the
flocculation tank which is mixed slowly by either mechanical means, such as mixers, or recirculation
pumping. The wastewater then undergoes a separation/dewatering process such as clarification or
filtration, where the precipitated metals are removed from solution. In a clarification system, a
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flocculant, such as a polymer, sometimes is added to aid in the settling process. The resulting sludge
from the clarifier or filter must be further treated, disposed, or recycled.
National estimates based on the Detailed Questionnaire data collected suggest that 33 percent of
indirect hazardous landfills, 5 percent of indirect non-hazardous landfills, and 11 percent of direct
non-hazardous landfill facilities employ chemical precipitation as part of wastewater treatment
systems. A typical chemical precipitation system is presented in Figure 8-5.
8.1.2.6
Chemical Oxidation/Reduction
Chemical oxidation treatment processes can be used to remove ammonia, to oxidize cyanide, to
reduce the concentration of residual organics, and to reduce the bacterial and viral content of
wastewaters. Both chlorine and ozone can be used to destroy residual organics in wastewater. When
these chemicals are used for this purpose, disinfection of the wastewater is usually an added benefit.
A further benefit of using ozone is the removal of color. Ozone can also be combined with hydrogen
peroxide for removing organic compounds hi contaminated groundwater. Oxidation also is used to
convert pollutants to end products or to intermediate products that are more readily biodegradable
or removed more readily by adsorption. National estimates based on the Detailed Questionnaire data
show that 33 percent of indirect hazardous landfills, 10 percent of direct non-hazardous landfills, and
less than one percent of indirect non-hazardous landfill facilities use chemical oxidation units as part
of wastewater treatment systems.
Chemical oxidation is a chemical reaction process in which one or more electrons are transferred from
the chemical being oxidized to the chemical initiating the transfer (the oxidizing agent). The electron
acceptor may be another element, including an oxygen molecule, or it may be a chemical species
containing oxygen, such as hydrogen peroxide, chlorine dioxide, permanganate, or ozone. This
process is also effective hi destroying cyanide and toxic organic compounds. Figure 8-6 presents a
process schematic for a chemical oxidation system that uses an alkaline chlorination process.
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Chemical oxidation is a potential treatment option for the removal of certain organic pollutants from
leachate or groundwater. The amount of oxidant required in practice is generally greater than the
theoretical mass calculated. The reasons for this are numerous and include incomplete oxidant
consumption and oxidant demand caused by other species in solution. Oxidation reactions are
catalysts and pH dependent; hence, pH control is an important design variable. Since economics are
an important factor, partial oxidation followed by additional treatment options may be more efficient
and cost effective than using a complete oxidation treatment scheme alone.
According to the Detailed Questionnaire data, landfill facilities use chemical oxidation processes to
treat cyanide-bearing wastes, organic pollutants, and as a disinfectant. When treating cyanide or
organic wastes, these processes use strong oxidizing chemicals, such as chlorine in elemental or
hypochlorite salt form. As a disinfection process, an oxidant (usually chlorine) is added to the
wastewater in the form of either chlorine dioxide or sodium hypochlorite. Other disinfectant
chemicals include ozone, hydrogen peroxide, sulfur dioxide, and calcium hypochlorite. Once the
oxidant is mixed with the wastewater, sufficient detention time (usually 30 minutes) is allowed for
the disinfecting reactions to occur (see reference 7).
Chemical reduction processes involve a chemical reaction in which electrons are transferred from one
chemical to another to reduce the chemical state of a contaminant. The main application of chemical
reduction in leachate treatment is the reduction of hexavalent chromium to trivalent chromium.
Chromium reduction is necessary due to the inability of hexavalent chromium to form a hydroxide,
thus enabling the trivalent chromium to be precipitated from solution in conjunction with other
metallic salts. Figure 8-7 presents a flow diagram of a chromium reduction system. Sulfur dioxide,
sodium bisulfate, sodium metabisulfate, and ferrous sulfate are typical reducing agents used at landfill
facilities.
8.1.2.7
Stripping
Stripping is an effective treatment method for removing dissolved volatile organic compounds from
wastewater. The removal is accomplished by passing air or steam through the agitated waste stream.
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The process results in a contaminated off-gas stream which, depending upon the air emissions
standards, usually requires air pollution control equipment. National estimates based on EPA's
Detailed Questionnaire data indicate that 4 percent of direct and greater than one percent of indirect
non-hazardous landfill facilities use air stripping as part of wastewater treatment systems.
8.1.2.7.1
Air Stripping
The driving force of air stripping mass-transfer operation is the difference in concentrations between
the air and liquid streams. Pollutants are transferred from the more concentrated wastewater stream
to the less concentrated air stream until equilibrium is reached; this equilibrium relationship is known
as Henry's Law. The strippability of a pollutant is expressed as its Henry's Law Constant, which is
a function of its volatility and solubility.
Air stripping (or steam stripping) can be performed in tanks or in spray or packed towers. Treatment
in packed towers is the most efficient application. The packing typically consists of plastic rings or
saddles. The two types of towers that are commonly used, cross flow and countercurrent, differ in
design only in the location of the air inlets. In the cross flow tower, the air is drawn through the sides
for the total length of the packing. The countercurrent tower draws its entire air flow from the
bottom. The cross flow towers have been found to be more susceptible to scaling problems and are
less efficient than countercurrent towers.
Figure 8-8 presents a flow diagram of a countercurrent air stripper.
8.1.2.8
FHtration
Filtration is a metfiod for separating solid particles from a fluid through the use of a porous medium.
The driving force in filtration is a pressure gradient caused by gravity, centrifugal force, or a vacuum.
Filtration treatment processes can be used at landfills to remove solids from wastewaters after
physical/chemical or biological treatment or as the primary source of leachate treatment. Filtration
processes include a broad range of media and membrane separation technologies from ultrafiltration
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to reverse osmosis. To aid in removal, the filter medium may be precoated with a filtration aid such
as ground cellulose or diatomaceous earth.
National estimates based on the Detailed Questionnaire data indicate that 10 percent of direct and less
than one percent of indirect non-hazardous landfill facilities have some form of filtration as part of
wastewater treatment systems including the following:
Type of Filtration System
Sand
Diatomaceous earth
Granular multimedia
Membrane
Fabric
% Non-Hazardous Facilities
Direct Indirect
5 <1
0 <1
6 <1
0 1
0 <1
Dissolved compounds in landfill wastewaters are sometimes pretreated to convert the compound to
an insoluble solid particle prior to filtration. Polymers are sometimes injected into the filter feed
piping downstream of feed pumps to enhance flocculation of smaller floes that may escape an
upstream clarifier. Pretreatment for iron and calcium is sometimes necessary to prevent fouling and
scaling.
The following sections discuss the various types of filtration in use at landfills facilities.
8.1.2.8.1
Sand Filtration
Sand filtration processes consist of either a fixed or moving bed of media that traps and removes
suspended solids from water passing through the media. There are two types of fixed sand bed filters:
pressure and gravity. Pressure filters contain media in an enclosed, watertight pressure vessel and
require a feed pump to force the water through the media. A gravity filter operates on the basis of
differential pressure of a static head of water above the media, which causes flow through the filter.
Filter loading rates for sand filters are typically between 2 to 6 gpm/sq ft (see reference 7).
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All fixed media filters have influent and effluent distribution systems consisting of pipes and fittings.
Strainers in the tank bottom are usually stainless steel screens. Layers of uniformly sized gravel also
serve as bottom strainers and as a support for the sand. For both types of filters, the bed builds up
head loss over time. Head loss is a measure of solids trapped in the filter. As the filter becomes filled
with trapped solids, the efficiency of the filtration process falls off, and the filter must be backwashed.
Filters are backwashed by reversing the flow so that the solids in the media are dislodged and can exit
the filter; sometimes air is dispersed into the sand bed to scour the media.
Fixed bed filters can be automatically backwashed when the differential pressure exceeds a preset
limit or when a timer starts the backwash cycle. Powered valves and a backwash pump are activated
and controlled by adjustable cam timers or electronic programmable logic controllers to perform the
backwash function. A supply of clean backwash water is required. Backwash water and trapped
particles are commonly discharged to an equalization tank upstream of the wastewater treatment
system's primary clarifier or screen for removal.
Moving bed filters use an air lift pump and draft tube to recirculate sand from the filter bottom to the
top of the filter vessel, which is usually open at the top. Dirty water entering the filter at the bottom
must travel upward, countercurrently, through the downward moving fluidized sand bed. Particles
are strained from the rising water and carried downward with the sand. Due to the difference in
specific gravity, the lighter particles are removed from the filter when the sand is recycled through
a separation box at the top of the filter or in a remote location. The heavier sand falls back into the
filter, while the lighter particles flow over a weir to waste. Moving bed filters are continuously
backwashed and have a constant rate of effluent flow.
8.1.2.8.2
Diatomaceous Earth
These filtration systems use diatomaceous earth, a natural substance, as a precoat on either a vacuum
or pressure filter arrangement to enhance removal efficiencies. In these instances, the diatomaceous
earth is placed as a thin layer over a screen. The wastewater then is passed through the layer of earth
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and screen, with the suspended particles being filtered. A vacuum can be drawn across the screen,
or pressure applied to the wastewater to help the liquid pass through the filter medium.
8.1.2.8.3
Multimedia Filtration
Multimedia, or granular bed, filtration is used for achieving supplemental removal of residual
suspended solids from the effluent of chemical or biological treatment processes. These filters can
be operated either by gravity or under pressure in a vessel. In granular bed filtration, the wastewater
stream is sent through a bed containing one or more layers of different granular materials. The solids
are retained in the voids between the media particles while the wastewater passes through the bed.
Typical media used in granular bed filters include anthracite coal, sand, and garnet. These media can
be used alone, such as in sand filtration, or in a multimedia combination. Multimedia filters are
designed such that the individual layers of media remain fairly discrete. This is accomplished by
selecting appropriate filter loading rates, media grain size, and bed density. Hydraulic loading rates
for a multi-media filter are between 4 to 10 gpm/sq ft (see reference 7).
A multimedia filter operates with the finer, denser media at the bottom and the coarser, less dense
media at the top. A common arrangement is garnet at the bottom of the bed, sand in the middle, and
anthracite coal at the top. Some mixing of these layers occurs and is anticipated. During filtration,
the removal of the suspended solids is accomplished by a complex process involving one or more
mechanisms, such as straining, sedimentation, interception, impaction, and adsorption. The medium
size is the principal characteristic that affects the filtration operation. If the medium is too small,
much of the driving force will be wasted in overcoming the frictional resistance of the filter bed. If
the medium is too large, small particles will travel through the bed, preventing optimum filtration.
The flow pattern of multimedia filters is usually top-to-bottom. Upflow filters, horizontal filters, and
billow filters are also used. A top-to-bottom multimedia filter is represented in Figure 8-9.
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8.1.2.8.4
Membrane Filtration
Membrane filtration systems refer to those processes which employ a semi-permeable membrane and
a pressure differential. Both reverse osmosis and ultrafiltration are commonly used membrane
filtration processes.
8.1.2.8.4.1 Ultrafiltration
Ultrafiltration uses a semi-permeable microporous membrane, through which the wastewater is passed
under pressure. Water and low molecular weight solutes, such as salts and surfactants, pass through
the membrane and are removed as permeate. Emulsified oils and suspended solids are rejected by the
membrane and removed with some of the wastewater as a concentrated liquid. The concentrate is
recirculated through the membrane unit until the flow of permeate drops. The permeate can either
be discharged or passed along to another treatment unit. The concentrate is contained and held for
further treatment or disposal. Several types of ultrafiltration membranes configurations are available;
tubular, spiral wound, hollow fiber, and plate and frame. A typical ultrafiltration system is presented
in Figure 8-10.
Ultrafiltration is commonly used for the treatment of metal-bearing and oily wastewaters. It can
remove substances with molecular weights greater than 500, including suspended solids, oil and
grease, large organic molecules, and complexed heavy metals (see reference 8). Ultrafiltration is used
when the solute molecules are greater than ten tunes the size of the solvent molecules and less than
one-half micron. The primary design consideration in ultrafiltration is the membrane selection. A
membrane pore size is chosen based on the size of the contaminant particles targeted for removal.
Other design parameters to be considered are the solids concentration, viscosity, and temperature of
the feed stream, and the membrane permeability and thickness.
8.1.2.8.4.2 Reverse Osmosis
Reverse osmosis is a separation process that uses selective semipermeable membranes to remove
dissolved solids, such as metal salts, from water. The membranes are more permeable to water than
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to contaminants or impurities. The water in the feed is forced through a membrane by applied
pressure which exceeds the osmotic pressure of the feed and becomes a permeate consisting of
treated wastewater. Molecules of water pass through the membrane while contaminants are flushed
along the surface of the membrane and exit as concentrate. The concentrate flow from a reverse
osmosis system ranges from 10 to 50 percent of the feed flow, with concentrations of dissolved solids
and contaminants approaching 10 times that of the feed water (see reference 6). The percentage of
water that passes through the membranes is a function of operating pressure, membrane type, and
concentration of the contaminants.
Cellulose acetate, aromatic polyamide, and thin-film composites are commonly used membrane
materials. Reverse osmosis membranes are configured into tubular, spiral wound, hollow fiber, or
plate and frame modules. Modules are inserted into long pressure vessels that can hold one or more
modules. Reverse osmosis systems consist of a pretreatment pump, a high pressure feed pump, one
or more pressure vessels, controls, and instrumentation. A tubular reverse osmosis module is shown
in Figure 8-11.
Membranes have a limited life depending upon application and are replaced when cleaning is no
longer effective. Membranes can be cleaned manually or chemically by recirculating the cleaning
solution through the membranes to restore performance. Membranes can also be removed from the
reverse osmosis system and sent off site for flushing and rejuvenation. Membranes are replaced when
cleaning is no longer effective.
Membrane pore sizes for a typical reverse osmosis system range from 0.0005 to 0.002 microns, while
pressures of 300 to 400 psi are usually encountered (see reference 39). Therefore, reverse osmosis
feed water needs to be very low in turbidity. Pretreatment of landfill wastewaters prior to reverse
osmosis treatment may be necessary, including chemical addition and clarification, or cartridge
filtration using 5 micron filters to remove suspended particulates from the influent in order to protect
pumps and membranes. Carbon adsorption is recommended as pretreatment for membranes sensitive
to chlorine: Biofouling can be prevented by chlorination and dechlorination of the feed water. To
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maintain the solubility of metals such as calcium, magnesium, and iron, the pH can be adjusted with
acid. Aside from pH adjustment, chemical requirements include: bactericide, dechlorination, and
chelating agents.
One variation of conventional reverse osmosis technology used at landfill facilities is an innovative
membrane separation technology using disc tube modules. This innovative process is designed to
treat liquid waste that is higher in dissolved solids content, turbidity, and contaminant levels than
waste treated by conventional membrane separation processes. This process also reduces the
potential for membrane fouling and scaling, which allows it to be the primary treatment for waste
streams such as landfill leachate.
The disc tube membrane module features larger feed flow channels and a higher feed flow velocity
than typical membrane separation systems (see reference 48). These characteristics allow the disc
tube module greater tolerance for dissolved solids and turbidity and a greater resistance to membrane
fouling and scaling. The high flow velocity, short feed water path across each membrane, and the
circuitous flow path create turbulent mixing to reduce boundary layer effects and minimize membrane
fouling and scaling.
Membrane material for the disc tube module is formed into a cushion with a porous spacer material
on the inside. The membrane cushions are alternately stacked with hydraulic discs on a tension rod.
The hydraulic disks support the membranes and provide the flow channels for the feed liquid to pass
over the membranes. After passing through the membrane material, permeate flows through
collection channels to a product recovery tank. A stack of cushions and disks is housed in a pressure
vessel. The number of disks per module, number of modules, and the membrane materials can be
varied to suit the application. Modules are typically combined in a treatment unit or stage. Disc tube
module units can be connected in series to improve permeate water quality or in parallel to increase
system treatment capacity (see reference 48).
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Like all membrane separation processes, reverse osmosis technology reduces the volume of the waste.
The degree of volume reduction is dependent on the waste characteristics and the system desiga
Reverse osmosis technology can treat liquid waste streams containing low molecular weight volatile
and semivolatile organics, metals and other inorganic compounds.
8.1.2.8.5
Fabric Filters
Fabric filters consist of a vessel that contains a cloth or paper barrier through which the wastewater
must pass. The suspended matter is screened by the fabric, and the effectiveness of the filter depends
on the mesh size of the fabric. Fabric filters can either be backwashed, or built as disposable units.
For waters having less than 10 mg/1 suspended solids, cartridge fabric filters may be cost effective.
Cartridge filters have very low capital cost and can remove particles of 1 micron or larger (see
reference 39). Using two-stage cartridge filters (coarse and fine) in series extends the life of the fine
cartridge. Disposable or backwashable bag filters also are available and may be quite cost effective
for certain applications. Typically, these fabric filters are used to remove suspended solids prior to
other filtrations systems to protect membranes and equipment and reduce solids fouling.
8.1.2.9
Carbon Adsorption
Activated carbon adsorption is a physical separation process in which organic and inorganic materials
are removed from wastewater by sorption, or attraction, and accumulation of the compounds on the
surface of the carbon granules. This process is commonly referred to as granular activited carbon
adsorption. While the primary removal mechanism is adsorption, biological degradation and filtration
are additional pollutant removal mechanisms provided by the activated carbon filter. Adsorption
capacities of 0.5 to 10 percent by weight are typical in industrial applications (see reference 5). Spent
carbon can either be regenerated on site, by processes such as wet-air oxidation or steam stripping,
or, for smaller operations, it can be regenerated off site or sent directly for disposal. Vendors of
carbon can exchange spent carbon with fresh carbon under contract.
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Activated carbon systems consist of a vessel containing a bed of carbon (usually 4 to 12 feet in
depth), whereby the wastewater is either passed upflow or downflow through the filter bed (see
reference 6). Carbon vessels are typically operated under pressure; however, some designs use
gravity beds. For smaller applications, granular activated carbon systems also are available in canister
systems, which can be readily changed-out and sent for off-site regeneration.
Often more than one carbon vessel is used in series, such that the first column can be used until the
carbon is "exhausted" before it is regenerated. The partially exhausted second column is then used
as the first column, and a second column is rotated behind it to provide polishing. Up to three
columns are typically used in a rotating fashion. When all of the available adsorption sites on the
granular activated carbon are occupied, a rise in organic concentrations is observed in the effluent
leaving the vessel. At this point the granular activated carbon in the vessel is saturated and is said to
have reached break-through.
The key design parameter is the adsorption capacity of the granular activated carbon. This is a
measure of the mass of contaminant adsorbed per unit mass of carbon and is a function of the
chemical compounds being removed, type of carbon used, and process and operating conditions. The
volume of carbon required is based upon the COD and/or pollutant-specific concentrations in the
wastewater to be treated and desired frequency of carbon change-outs. The vessel is typically
designed for an empty bed contact time of 15 to 60 minutes (see reference 5). Non-polar, high
molecular weight organics with low solubility are readily adsorbed using GAC. Certain organic
compounds have a competitive advantage for adsorption onto GAC, which results in compounds
being preferentially adsorbed or causing other less competitive compounds to be desorbed from the
GAC. Most organic copounds and some metals typically found in landfill leachate are effectively
removed using GAC.
National estimates based on EPA's Detailed Questionnaire data indicate that one percent of indirect
and greater than one percent of direct non-hazardous landfill facilities employ carbon adsorption as
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part of wastewater treatment systems. Figure 8-12 presents a flow diagram of a typical carbon
adsorption vessel.
8.1.2.10 Ion Exchange
Ion exchange is an adsorption process that uses a resin media to remove contaminants from
wastewaters. Ion exchange is commonly used for the removal of heavy metals from relative^
low-concentration waste streams. A key advantage of the ion exchange process is that it allows for
the recovery and reuse of the metal contaminants. Ion exchange also can be designed to be selective
to certain metals and can provide effective removal from wastewater having high concentrations of
background compounds such as iron, magnesium, and calcium. A disadvantage is that the resins can
be fouled by oils and heavy polymers. Pretreatment for groundwater or leachate treated by an ion
exchange system typically includes a cartridge filtration unit. Additional tanks and pumps are
required for regeneration, chemical feed, and collection of spent solution.
In an ion exchange system, the wastewater stream is passed through a bed of resin. The resin
contains bound groups of ionic charge on its surface, which are exchanged for ions of the same
charge in the wastewater. Resins are classified by type, either cationic or anionic; the selection is
dependent upon the wastewater contaminant to be removed. Cation resins adsorb metals, while anion
resins adsorb such contaminants as nitrate and sulfate. A commonly-used type resin is polystyrene
copolymerized with divinylbenzene. Key parameters for designing an ion exchange system include
a resin bed loading rate of 2 to 4 gallons per minute per cubic foot, and a pressure vessel diameter
providing for a cross-sectional area loading rate of 5 to 8 gallons per minute per square foot (see
reference 5).
The ion exchange process involves four steps: treatment, backwash, regeneration, and rinse. During
the treatment step, wastewater is passed through the resin bed. The ion exchange process continues
until pollutant breakthrough occurs. The resin is then backwashed to reclassify the bed and to remove
suspended solids. During the regeneration step, the resin is contacted with either an acidic or alkaline
solution containing the ion originally present hi the resin. This "reverses" the ion exchange process
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and removes the metal ions from the resin. The bed is then rinsed to remove residual regenerating
solution. The resulting contaminated regenerating solution must be further processed for reuse or
disposal. Depending upon system size and economics, some facilities choose to remove the spent
resin and replace it with resin regenerated off-site instead of regenerating the resin in-place.
Ion exchange equipment ranges from simple, inexpensive systems such as domestic water softeners,
to large, continuous industrial applications. A common industrial setup is fixed-bed resin in a vertical
column, where the resin is regenerated in-place. Other operating modes include batch and fluidized
bed. These systems can be designed so that the regenerant flow is concurrent or countercurrent to
the treatment flow. A countercurrent design, although more complex to operate, provides a higher
treatment efficiency. The beds can contain a single type of resin for selective treatment, or the beds
can be mixed to provide for more complete deionization of the waste stream. Often, individual beds
containing different resins are arranged hi series, which makes regeneration easier than in the mixed
bed system.
National estimates based on the Detailed Questionnaire data show that less than one percent of
indirect non-hazardous landfills employ some form of ion exchange as part of wastewater treatment
systems. Figure 8-13 presents a flow diagram of a typical ion exchange setup, fixed bed resin in a
vertical column.
8.1.3 Biological Treatment
Biological treatment uses microbes which consume, and thereby destroy, organic compounds as a
food source. Leachate from landfills can contain large quantities of organic materials that can be
readily stabilized using biological treatment processes. In addition to the carbon food source
supplied by the organic pollutants, the microbes also require energy and supplemental nutrients for
growth, such as nitrogen and phosphorus. Aerobic microbes require oxygen to grow, whereas
anaerobic microbes grow in the absence of oxygen. An adaptive type of anaerobic microbe, called
a facultative anaerobe, can grow with or without oxygen.
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The success of biological treatment in treating wastewaters is also dependent on other factors, such
as the pH and temperature of the wastewater, the nature of the pollutants, the nutrient requirements
of the microbes, the presence of other inhibiting pollutants (such as toxic heavy metals), and
variations in the feed stream loading.
Aerobic biological treatment systems utilize an acclimated community of microorganisms to degrade,
coagulate, and remove organic and other contaminants from wastewater. Organic contaminants in
the wastewater are used by the treatment organisms for biological synthesis and growth, with a small
portion for cellular maintenance. Resulting products from biological treatment include cellular
biomass, carbon dioxide, water and, sometimes, the nondegradable fraction of the organic material.
For biological treatment to occur, wastewater is mixed or introduced to the biomass. The
microorganisms responsible for stabilization can be maintained in suspended form or can be attached
to a solid media. Examples of the suspended growth biological treatment systems include various
activated sludge treatment processes and aerobic lagoons. Biological treatment processes which
employ the use of fixed firm media include trickling filtration, biotowers, and rotating biological
contactors.
Anaerobic biological treatment systems can degrade organic matter in wastewater and ultimately
convert carbonaceous material into methane and carbon dioxide. Anaerobic systems have been
shown to be most effective for high strength leachate (COD over 4,000 mg/1) and for wastewaters
containing refractory contaminants because of effectiveness of methanotropic microorganisms in
metabolizing these compounds. A disadvantage to anaerobic treatment systems is the sensitivity of
the methanotropic microorganisms to certain toxic substances.
Initially, in an anaerobic treatment process, the complex organic matter in the raw waste stream is
converted to soluble organics by extra-cellular enzymes. This step facilitates the later conversion of
soluble organic matter into simple organic acids. The final step involves the conversion of organic
acids into methane and carbon dioxide. The bacteria responsible for the conversions have very slow
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growth rates. In addition, methanotropic bacteria are very sensitive to environmental conditions,
require the complete absence of oxygen, a narrow pH range (6.5 to 7.5), and can be readily inhibited
by the presence of toxic compounds such as certain heavy metals.
The number of landfill facilities estimated to use variations of biological treatment as part of
wastewater treatment systems is presented below:
Tvr>e of Biological Treatment
% Non-Hazardous Facilities % Hazardous Facilities
Direct Indirect
Activated Sludge
Aerobic Lagoon Systems
Facultative Lagoons
Trickling Filters
Anaerobic Systems
Powdered Activated Carbon Treatment (PACT)*
* with Activated Sludge
Nitrification Systems
Rotating Biological Contactors (RBCs)
Sequencing Batch Reactors (SBRs)
Denitrification Systems
Other*
* includes aerated submerged fixed film and wetlands
7
6
6
0
2
2
0
11
1
3
=a
o
o
o
o
o
Indirect
33
0
0
0
0
0
0
0
33
0
0
The following sections present a discussion of biological treatment systems in use at landfill facilities.
8.1.3.1 Lagoon Systems
A body of water contained in an earthen dike and designed for biological treatment is termed a lagoon
or stabilization pond or oxidation pond. While in the lagoon, wastewater is biologically treated to
reduce degradable organics and also to reduce suspended- solids through sedimentation. The
biological process taking place in the lagoon can be aerobic, anaerobic or both (faicultative),
depending on the design. Because of the low construction and operating costs, lagoons offer a
financial advantage over other treatment methods and are popular where sufficient land is available
at reasonable cost.
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Lagoons are used in wastewater treatment for stabilization of suspended, dissolved and colloidal
organics either as a main biological treatment process or as a polishing treatment process following
other biological treatment systems. Aerobic, facultative and aerated lagoons are generally used for
wastewater of low and medium organic strength. High strength wastewaters and wastewaters of
variable strength often are treated by a series of lagoons; a common configuration is an anaerobic
lagoon, followed by a facultative lagoon and an aerobic lagoon.
The performance of lagoons in removing degradable organics depends on detention time,
temperature, and the nature of the waste. Aerated lagoons generally provide a high degree of BOD5
reduction more consistently than aerobic or facultative lagoons. Typical problems associated with
lagoons are excessive algae growth, offensive odors from anaerobic lagoons if sulfates are present
and the lagoon is not covered, and seasonal variations in effluent quality.
The major classes of lagoons that are based on the nature of biological activities are discussed below.
Aerobic lagoons depend on algae photosynthesis and natural aeration to assist in the biological
activity. These shallow lagoons (3 to 4 feet in depth) rely on both the natural oxygen transfer
occurring through the surface area of the lagoon and the production of oxygen from photosynthetic
algae. Aerobic lagoons are generally suitable for treating low to medium strength landfill leachates
due to the recommended smaller food to mass ratios. Because of this design limitation, aerobic
lagoons are used in combination with other lagoons to treat higher strength landfill leachates to
achieve additional organic removal following conventional wastewater treatment processes. The
typical hydraulic detention time for an aerobic lagoon is 10 to 40 days, with an organic loading of 60
to 120 pounds of BOD5 per day per acre (see reference 7).
A variation of the aerobic lagoon is the aerated lagoon. These lagoons do not depend on algae and
sunlight to furnish dissolved oxygen, but require additional oxygen to be introduced to prevent
anaerobic conditions. In these systems, mechanical or diffused aeration devices are used in the
lagoons for oxygen transfer and to create some degree of mixing (see Figure 8-14). Due to this
mixing, additional suspended solids removal in the effluent from the lagoon may be required. The
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recommended hydraulic detention time is 3 to 20 days, with an organic loading of 20 to 400 pounds
of BODS per day per acre (see reference 7). Based on these higher design loading rates, aerated
lagoons are well suited for treatment of medium strength landfill leachates.
Aerated lagoons are relatively simple to operate. The influent is fed into the basin where it is mixed
and aerated with the lagoon contents. Settled sludge is not routinely withdrawn from the lagoon.
Lagoons require only periodic cleanings when the settled solids significantly reduce lagoon volume.
Since operation requires no sludge recycle, the hydraulic detention time is equal to the sludge
retention time. Contaminant reduction in a lagoon system is typically less than other biological
treatment systems. As a result, aerobic lagoons are commonly used together with other
physical/chemical treatment processes, such as lime addition and settling, to ensure sufficient pollutant
removal efficiencies.
Anaerobic lagoons are relatively deep ponds (up to 6 meters) with steep sidewalls in which anaerobic
conditions are maintained by keeping organic loading so high that complete deoxygenation is
prevalent Some oxygenation is possible in a shallow surface zone. If floating materials in. the waste
form an impervious surface layer, complete anaerobic conditions will develop. Treatment or
stabilization results from anaerobic digestion of organic wastes by acid-forming bacteria that break
down organics. The resultant acids are then converted to carbon dioxide, methane, and other end
products. Anaerobic lagoons are capable of providing treatment of high strength wastewaters and
are resistant to shock loads.
In the typical anaerobic lagoon, raw wastewater enters near the bottom of the pond (often at the
center) and mixes with the active microbial mass in the sludge blanket, which can be as much as 2
meters (6 feet) deep. The discharge is located near one of the sides of the pond, submerged below
the liquid surface. Excess sludge is washed out with the effluent and recirculation of waste sludge
is not required.
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Anaerobic lagoons are customarily contained within earthen dikes. Depending on soil and wastewater
characteristics, lining with various impervious materials, such as rubber, plastic, or clay may be
necessary. Pond geometry may vary, but surface area-to-volume ratios are ninimized to enhance heat
retention.
Waste stabilization in a facultative lagoon treatment system is accomplished by a combination of
anaerobic microorganisms, aerobic microorganisms, and a preponderance of facultative
microorganisms that thrive under anaerobic, as well as aerobic conditions. Facultative systems
consist of lagoons of intermediate depth (3 to 8 feet) in which the wastewater is stratified into three
zones (see Figure 8-15). These zones consist of an anaerobic bottom layer, an aerobic surface layer,
and an intermediate zone dominated by the facultative microorganisms. Stratification is a result of
solids settling and temperature-water density variations. Oxygen in the surface zone is provided by
natural oxygen transfer and photosynthesis or, as in the case of an aerated facultative lagoon, by
mechanical aerators or diffusers. Facultative lagoons usually consist of earthen dikes, but some are
lined with various impervious materials, such as synthetic geomembranes or clay.
A facultative lagoon is designed to permit the accumulation of settleable solids on the basin bottom.
This sludge at the bottom of the facultative lagoon will undergo anaerobic digestion, producing
carbon dioxide and methane. The liquid and gaseous intermediate products from the accumulated
solids, together with the dissolved solids furnished in the influent, provide the food for the aerobic
and facultative bacteria in the upper layers of the liquid in the lagoon. Recommended hydraulic
detention time for a facultative lagoon without aeration is 7 to 30 days, with an organic loading of
15 to 50 pounds of BOD5 per day per acre (see reference 7).
8.1.3.2
Anaerobic Systems
There are several process variations for anaerobic biological treatment: complex mix anaerobic
digesters (see Figure 8-16), contact reactors with sludge recycle, and anaerobic filters. A digestor
uses an air tight reactor where wastes are mixed with digestor contents that contain the suspended
anaerobic microorganisms. A digestor operated in a complete mix mode without sludge recycling
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has a hydraulic detention time equal to the solids retention time. Anaerobic digestion in a reactor
can also occur with sludge recycling. This permits a much larger solids retention time (SRT) than
the hydraulic detention time. System stability is greater at increased SRTs and, since the hydraulic
detention time can be decreased, the reactor volume can also be reduced. The anaerobic filter or
biotower microbes are maintained in a film on packed solid media within an air tight column. A
variation of the anaerobic fixed-film process is a fluidized bed process. The basic tower design is
similar to that of an aerobic reactor in that the influent is fed into the reactor at counter-current flow.
This process provides for very high SRTs and variable hydraulic detention times.
Stabilization of leachate in an anaerobic treatment unit requires the maintenance of a viable
community of anaerobic microbes. Treatment efficiency is dependent on many interrelated factors
including: hydraulic detention time, SRT, temperature, and to a lesser extent organic loading,
nutrients, and toxics. Microorganisms responsible for degrading the organic waste must remain in
the reactor long enough to reproduce. When the microbes spend less time in the system than they
require to reproduce, the solids are eventually washed out of the system. Anaerobic treatment
facilities are reportedly designed with an SRT of 2 to 10 times the washout time (typical washout time
reported for organic acids are about 3.5 days). For degradation of organic acids in leachate, this
would yield an SRT of 7 to 35 days (see reference 7). The most common temperature regime for an
anaerobic reactor is in the range of 25 to 38 degrees C (see reference 7). Typical loadings for
anaerobic systems are from 30 to 100 pounds of COD per 1,000 cubic feet of reactor volume (see
reference 7). Since the synthesis of new cellular material is slow, nutrient requirements are not as
large as in aerobic systems. Nutrient addition needs to be evaluated, and in the case of leachate with
low phosphorus concentrations, will require phosphorus addition.
8.1.3.3 Attached Growth Biological Treatment Systems
Attached growth biological treatment systems are used to biodegrade the organic components of a
wastewater. In these systems, the biomass adheres to the surfaces of rigid supporting media. As
wastewater contacts the supporting medium, a thin-fihn biological slime develops and coats the
surfaces. As this film (consisting primarily of bacteria, protozoa, and fungi) grows, the slime
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periodically breaks off the medium and is replaced by new growth. This phenomenon of losing the
slime layer is called sloughing and is primarily a function of organic and hydraulic loadings on the
system. The effluent form the system is usually discharged to a clarifier to settle and remove the
agglomerated solids.
Attached growth biological systems are applicable to industrial wastewaters amenable to aerobic to
biological treatment in conjunction with suitable pre- and post-treatment units. These systems are
effective for the removal of suspended or colloidal materials.
The three major types of attached growth systems used at landfills facilities are rotating biological
contactors, trickling filters, and fluidized bed biological reactors. These processes are described
below.
Rotating biological contactors are a form of aerobic attached growth biological system where the
biomass adheres to the surface of a rigid media. In a rotating biological contactor, the rigid media
usually consists of a plastic disk or corrugated plastic medium mounted on a horizontal shaft (see
Figure 8-17). The medium slowly rotates in wastewater (with 40 to 50 percent of its surface
immersed) as the wastewater flows past. During the rotation, the medium picks up a thin layer of
wastewater, which flows over its surface absorbing oxygen from the air. The biological mass growing
on the medium surface absorbs organic pollutants, which then are biodegraded. Excess
microorganisms and other solids are continuously removed from the film on the disk by shearing
forces created by the rotation of the disk in the wastewater. The sloughed solids are carried with the
effluent to a clarifier, where they are separated from the treated effluent.
Rotating biological contactors provide a greater degree of flexibility for landfills with changing
leachate characteristics. Modular construction of rotating biological contactors permit then- multiple
staging to meet increases or decreases in treatment demand. Staging, which employs a number of
rotating biological contactors operated in series, enhances biological treatment efficiency, improves
shock-handling ability, and also may aid in achieving nitrification.
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Typical rotating biological contactor design parameters include a hydraulic loading of 2.0 to 4.0
gallons per square feet per day and an organic loading of 2.0 to 3.5 pounds BOD5 per 1,000 square
feet per day (see reference 12).
Factors which affect the efficiency of rotating biological contactor systems include the type and
concentration of organic matter, hydraulic detention tune, rotational speed, media surface area
submergence, and pre- and post-treatment activities. Variations of the basic rotating biological
contactor process design include the addition of air to the tanks, chemicals for pH control, use of
molded covers or housing for temperature control, and sludge recycle to enhance nitrification.
Rotating biological contactors are reportedly well suited for the treatment of soluble organics and
adequate for nitrification. They are low-rate systems capable of handling limited loadings capacity
and are not efficient for degrading refractory compounds or removing metals (see reference 7).
Trickling nitration is another aerobic fixed-film biological treatment process that consists of a suitable
structure, packed with inert medium, such as rock, wood, or plastic. The wastewater is distributed
over the upper surface of the medium by either a fixed spray nozzle system or a rotating distribution
system (see Figure 8-18). The inert medium develops a biological slime that absorbs and biodegrades
organic pollutants. Air flows through the filter by convection, thereby providing the oxygen needed
to maintain aerobic conditions.
Trickling filters are classified as low-rate or high-rate, depending on the organic loading. Typical
design organic loading values range from 5 to 25 pounds and 25 to 45 pounds BOD5 per 1,000 cubic
feet per day for low-rate and high-rate, respectively (see reference 11). A low-rate filter generally
has a media bed depth of 1.5 to 3 meters and does not use recirculation. A high-rate filter can have
a bed depth from 1 to 9 meters and recirculates a portion of the effluent for further treatment (see
reference 7).
A variation of a trickling filtration process is the aerobic biotower which can be operated in a
continuous or semi-continuous manner. Influent is pumped to the top of a tower, where/it flows by
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gravity through the tower. The tower is packed with media, plastic or redwood, containing the
microbial growth. Biological degradation occurs as the wastewater passes over the media. Treated
wastewater collects into the bottom of the tower. If needed, additional oxygen is provided via air
blowers counter current to the wastewater flow. Alternative variations of this treatment process
involve the inoculation of the raw influent with bacteria, adding nutrients, and using upflow
biotowers. Wastewater collected in the biotowers is delivered to a clarifier to separate the biological
solids from the treated effluent.
An aerobic fluidized bed biological reactor is a variation of a fixed film biological treatment process.
Microorganisms are grown on either granular activated carbon or sand media. Influent wastewater
enters the reactor through a distributor which is designed to provide for fluidization of the media (see
Figure 8-19). As the biofilm grows, the media bed expands, thereby reducing the density of the
media. The rising bed is intercepted at a given height with the bulk of the biomass removed from the
media. The media then is returned to the reactor. Additional oxygen can be predissolved in the
influent to enhance performance. The use of granular activated carbon as a medium integrates
biological treatment and carbon adsorption processes, which has the advantage of handling loading
fluctuations, as well as greater removals of organic contaminants.
Due to a short hydraulic detention time, this process is favorable for low to moderate levels f
contamination. The vertical installation of the reactor and high loading capability reduces
conventional land requirements. The maximum design loading is 400 pounds of COD per 1,000
square feet of reactor area per day with a minimum hydraulic detention time of 5 to 10 minutes (see
reference 7).
8.1.3.4
Activated Sludge
The activated sludge process is a specific continuous-flow, aerobic biological treatment process that
employs suspended-growth aerobic microorganisms to biodegrade organic contaminants. In this
process (shown in Figure 8-20), a suspension of aerobic microorganisms is maintained in.a relatively
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homogeneous state by mechanical mixing or turbulence induced by diffused aerators hi an aeration
basin. This suspension of microorganisms is called the mixed liquor.
Influent is introduced into the basin and is allowed to mix with the tank contents. The biological
process often is preceded by gravity settling to remove larger and heavier suspended solids. A series
of biochemical reactions is performed hi the aeration tank that degrade organics and generate new
biomass. Microorganisms oxidize the soluble and suspended organic pollutants to carbon dioxide and
water using the available supplied oxygen. These organisms also agglomerate colloidal and
participate solids. After a specific contact period hi the aeration basin, the mixture is passed to a
settling tank where the microorganisms are separated from the treated water. A portion of the settled
solids in the clarifier is recycled back to the aeration system to maintain the desired concentration of
microorganisms in the reactor. The remainder of the settled solids is wasted and sent to sludge
handling facilities.
To ensure biological stabilization of organic compounds hi activated sludge systems, adequate
nutrient levels must be available to the biomass. The primary nutrients are nitrogen and phosphorus.
Lack of these nutrients can impair biological activity and result hi reduced removal efficiencies.
Certain leachates can have low concentrations of nitrogen and phosphorus relative to the oxygen
demand. As a result, nutrient supplements (e.g., phosphoric acid addition for additional phosphorus)
have been used hi activated sludge systems at landfill facilities.
The effectiveness of the activated sludge process is governed by several design and operation
variables. The key variables are organic loading, sludge retention time, hydraulic or aeration
detention time, oxygen requirements, and the biokinetic rate "constant (K). The organic loading is
described as the food-to-microorganism (F/M) ratio, or kilograms of BOD5 applied daily to the
system per kilogram of mixed liquor suspended solids (MLSS). The MLSS hi the aeration tank is
determined by the rate and concentration of activated sludge returned to the tank. The organic
loading (F/M ratio) affects the BOD5 removal, oxygen requirements, biomass production, and the
settleability of the biomass. The sludge retention time (SRT) or sludge age is a measure of the
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average retention time of solids in the activated sludge system. Sludge retention time is important
in the operating of an activated sludge system as it must be maintained at a level that is greater than
the maximum generation time of microorganisms in the system. If adequate sludge retention time is
not maintained, Hie bacteria are washed from the system faster than they can reproduce themselves
and the process fails. The SRT also affects the degree of treatment and production of waste sludge.
A high SRT results in carrying a high quantity of solids in the system and obtaining a higher degree
of treatment and also results in the production of less waste sludge. The hydraulic detention time is
used to determine the size of the aeration tank and should be determined by use of F/M ratio, SR
and MLSS. The biokinetic rate constant (or K-rate) determines the speed of the biochemical oxygen
demand reaction and generally ranges from 0.1 to 0.5 days"1 for municipal wastewaters (see reference
11). The value of K for any given organic compound is temperature-dependent; because
microorganisms are more active at higher temperatures, the value of K increases with increasing
temperature. Oxygen requirements are based on the amount required for BOD5 synthesis and the
amount required for endogenous respiration. The design parameters will vary with the type of
wastewater to be treated and are usually determined in a treatability study. The oxygen requirement
to satisfy the BOD5 synthesis is established by the characteristics of the wastewater. The oxygen
requirement to satisfy endogenous respiration is established by the total solids maintained in the
system and their characteristics.
Modifications of the activated sludge process are common, as the process is extremely versatile and
can be adapted for a wide variety of organically contaminated wastewaters. The typical modification
may represent a variation in one or more of the key design parameters, including the F/M loading,
aeration location and type, sludge return, and contact basin configuration. The modifications in
practice have been identified by the major characteristics that distinguish the particular configuration.
The characteristic types and modifications are briefly described as follows:
Conventional. The aeration tanks are long and narrow, with plug flow (i.e., little forward or
backwards mixing).
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• Complete Mix. The aeration tanks are shorter and wider, and the aerators, diffusers, and
entry points of the influent and return sludge are arranged so that the wastewater mixes
completely.
• Tapered Aeration. A modification of the conventional process in which the diffusers are
arranged to supply more air to the influent end of the tank, where the oxygen demand is
highest.
• Step Aeration. A modification of the conventional process in which the wastewater is
introduced to the aeration tank at several points, lowering the peak oxygen demand.
• High Rate Activated Sludge. A modification of conventional or tapered aeration in which the
aeration times are shorter, the pollutants loadings are higher per unit mass of microorganisms
in the tank.. The rate of BOD5 removal for this process is higher than that of conventional
activated sludge processes, but the total removals are lower.
• Pure Oxygen. An activated sludge variation in which pure oxygen instead of air is added to
the aeration tanks, the tanks are covered, and the oxygen-containing off-gas is recycled.
Compared to normal air aeration, pure oxygen aeration requires a smaller aeration tank
volume and treats high-strength wastewaters and widely fluctuating organic loadings more
efficiently.
• Extended Aeration. A variation of complete mix in which low organic loadings and long
aeration times permit more complete wastewater degradation and partial aerobic digestion
of the microorganisms.
• Contact Stabilization. An activated sludge modification using two aeration stages. In the
first, wastewater is aerated with the return sludge in the contact tank for 30 to 90 minutes,
allowing finely suspended colloidal and dissolved organics to absorb to the activated sludge.
The solids are settled out in a clarifier and then aerated in the sludge aeration (stabilization)
tank for 3 to 6 hours before flowing into the first aeration tank (see reference 11).
• Oxidation Ditch Activated Sludge. An extended aeration process in which aeration and
mixing are provided by brush rotors placed across a race-track-shaped basin. Waste enters
the ditch at one end, is aerated by the rotors, and circulates.
Activated sludge systems are effective in the removal of soluble (dissolved) organics by biosorption
as well as suspended and colloidal matter typically found in landfill leachate. Suspended matter s
removed by entrapment in the biological floe while colloidal matter is removed by physiochemical
adsorption to the biological floe. For example, inorganic contaminants, such as heavy metals, that
are common in landfill wastewaters, often are precipitated and concentrated hi the biological sludges
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generated from activated sludge systems at landfill facilities. Halogenated organic compounds may
be driven off to a certain extent in the aeration process while other less volatile compounds are
removed by a combination of biodegradation and air stripping in the aeration basin. Finally, activated
sludge systems treating landfill leachates with an excess loading of certain nutrients (i.e. amounts of
nitrogen that exceed the requirements of the biomass in the activated sludge system) can be operated
so that nitrification of these nutrients can occur in the activated sludge system. For higher
concentrations, stand-alone nitrification systems may be required; these systems are discussed later
in this chapter.
Conventional, plug flow activated sludge systems can adequately treat the organic loadings found in
low to medium strength landfill leachates. Higher strength leachates often are treated at landfill
facilities using extended aeration mode of activated sludge treatment. This process allows for a large
hydraulic detention time of up to 29 hours and for a sludge detention time of 20 to 30 days (see
reference 7). Aerator loading for the complete mix extended aeration process is between 10 to 15
pounds of BOD5 per 1,000 cubic feet of aerator tank volume (see reference 7). Extended aeration
also provides for minimal operator supervision as compared to other activated sludge processes and
occasional sludge wasting. EPA sampled a facility (EPA sampling Episode 4759) in the Hazardous
subcategory that lined a complete mix extended aeration treatment process for high strength leachate.
Design parameters for this system include influent BOD5 loading of 3520 mg/1 with a hydraulic
detention time of 28 hours. Higher strength leachates are also occasionally treated with a
combination of biological processes, sometimes using a lagoon or attached growth system prior to
the activated sludge system to reduce organic loading. Since activated sludge systems are sensitive
to the loading and flow variations typically found at landfill facilities, equalization is often require
prior to activated sludge systems treatment. Also, activated sludge systems treating landfill leachates
typically generate excess amounts of secondary sludge that may require additional stabilization,
dewatering and disposal.
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8.1.3.5
Powdered Activated Carbon Biological Treatment
In this biophysical treatment process, powdered activated carbon is added to a biological treatment
system (usually an activated sludge system). The adsorbent qualities of the powdered carbon aid in
the removal of organic compounds, particularly those that may be difficult to biodegrade. Powdered
activated carbon also enhances color removal and the settling characteristics of the biological floe.
The mixture of influent, activated sludge biomass, and powdered activated carbon is held in the
aeration basin for a sufficient detention tune adequate for the desired treatment efficiencies (see
Figure 8-21). After contact in the aeration basin, the mixture flows to a clarifier, where settled solids
are fed back to the aeration basin to maintain adequate concentrations of microorganisms and carbon.
Clear overflow from the clarifiers is either further processed or discharged. Fresh carbon is
periodically added to the aeration basin as required and is dependent on desired removal efficiencies.
Excess solids are removed directly from the recycled sludge stream. Wasted solids can be processed
by conventional dewatering means or by wet-air oxidation for the destruction of organics and
regeneration of activated carbon. Regeneration also can be handled off site for smaller applications.
Powdered activated carbon activated sludge treatment combines physical adsorption properties of
carbon with biological treatment, achieving a higher degree of treatment than possible by either mode
alone. Powdered activated carbon removes the more difficult to degrade refractory organics,
enhances solids removal, and buffers the system against loading fluctuations and shock loads.
Variations of the powdered activated carbon biological process includes operation hi a batch fill and
draw mode (similar to a sequencing batch reactor), multiple-stage powdered activated carbon units,
and combinations of aerobic and anaerobic powdered activated carbon biological systems. Operation
in a batch mode provides for flexibility in the system, by readily allowing for adjustments to the tune
and aeration mode in each process stage. This mode of operation is particularly applicable to the
treatment of leachate with variable composition and strength. The powdered activated carbon
biological treatment process is well suited for the treatment of leachate containing high concentrations
of soluble organics (particularly with low BODS to COD ratios). It can obtain better color and
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refractive organics removal than conventional biological processes and can provide for treatment of
leachates contaminated with various trace organic compounds.
8.1.3.6 Sequencing Batch Reactors (SBRs)
A sequencing batch reactor is a suspended growth biological system in which the wastewater is mixed
with existing biological floe in an aeration basin. SBRs are unique in that a single tank acts as an
equalization tank, an aeration tank, and a clarifier (see Figure 8-22). A SBR is operated on a batch
basis where the wastewater is mixed and aerated with the biological floe for a specific period of time.
The contents of the basin then are allowed to settle and the liquid (or supernatant) is decanted. The
batch operation of a sequencing batch reactor makes it applicable to wastewaters that are highly
variable because each batch can be treated differently, depending its waste characteristics.
A sequencing batch reactor system has four cycles: fill, react, settle, and decant. The fill cycle has
three phases. The first phase, called static fill, introduces the wastewater to the system under static
conditions. During this phase, anaerobic conditions can exist. During the second phase, the
wastewater is mixed to eliminate the scum layer and to initiate the oxygenation process. The third
phase consists of aeration and biological degradation. The react cycle is a time-dependent process
that continually mixes and aerates the wastewater while allowing the biological degradation process
to complete. Because the reaction is a batch process, the period of time of aeration can vary to match
the characteristics and loadings of the wastewater. The settling cycle utilizes a large surface area
(entire reactor area) and a lower settling rate than used in conventional sedimentation processes, to
allow for settling under quiescent conditions. Next, during the decant cycle, approximately one-third
,of the tank volume is removed by subsurface withdrawal. This treated effluent then can be further
treated or disposed. The period of time that the reactor waits prior to the commencement of another
batch processing is the idle period. Excess biomass is periodically removed from the sequencing
batch reactor when the quantity exceeds that needed for operation and is usually dewatered prior to
disposal.
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A sequencing batch reactor carries out all of the functions of a conventional continuous flow
activated sludge process, such as equalization, biological treatment, and sedimentation, in a time
sequence rather than a space sequence. Detention times and loadings vary with each batch and are
highly dependent on the loadings in the raw wastewater at that time. Typically, a sequencing batch
reactor operates with a hydraulic detention time of 1 to 10 days with an SRT of 10 to 30 days. The
MLSS is maintained at 3,500 to 10,000 mg/l (see reference 7). The overall control of the system can
be accomplished automatically by using level sensors or tuning devices. By using a single tank to
perform all of the required functions associated with biological treatment, a sequencing batch reactor
saves on land requirements. It also provides for greater operation flexibility for treating leachate with
viable waste characteristics by being able to readily vary detention time and mode of aeration in each
stage. Sequencing batch reactors also can be used to achieve complete nitrification/deni.trification
and phosphorus removal.
8.1.3.7
Nitrification Systems
In this process, nitrifying bacteria are used in an aerobic biological treatment system to convert
ammonia compounds to nitrate compounds. Nitrification is usually followed by denitrification (see
next section) which converts nitrates to nitrogen gas. Nitrifying bacteria, such as nitrosomonas and
nitrobacter, derive their energy for growth from the oxidation of inorganic nitrogen compounds.
Nitrosomonas converts ammonia to nitrites, and nitrobacter converts nitrites to nitrates.
The nitrification process usually follows a standard biological process that has already greatly reduced
the organic content of the wastewater; however, there are some biological systems that can provide
organic (BODS) removal concurrently with ammonia destruction. The nitrification process can be
oriented as either a suspended growth process (e.g. activated sludge system) or a attached growth
process (e.g. trickling filter).
8.1.3.8 Denitrification Systems
Denitrification is an anoxic process whereby nitrate nitrogen is converted to gaseous nitrogen, and
possibly nitrous oxide and nitric oxide. Denitrification is a two step process in which the first step
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converts nitrates to nitrites, and the second step converts nitrite to nitrogen gas. The bacteria use
nitrogen as an electron source rather than oxygen in digesting a carbon food source. Since the waste
stream reaching the denitrification process has low levels of organic material, a carbon source (usually
methanol) must be added.
The denitrification process can occur as a suspended growth process or as an attached growth
process. Attached growth systems can be designed as either fixed-bed or fluidized bed reactor
systems. Effluents from denitrification processes may need to be re-aerated to meet dissolved oxygen
discharge requirements.
8.1.3.9
Wetlands Treatment
An alternative and innovative biological treatment technology for treating landfill wastewaters is
wetland treatment. Wetlands can either be natural or man-made (artificial) systems and contain
vegetation that allow for the natural attenuation of contaminants. Wetlands are designed to provide
for a contact time of usually 10 to 30 days. Vegetation in the wetlands transforms nutrients and
naturally degrades organics. Certain metals also can be absorbed by vegetation through root systems.
Key design variables include loading rates, climatic constraints, and site characteristics. Wetland
systems are mainly still experimental and are not a widely accepted or proven treatment technology
for the treatment of landfill leachate.
8.1.4 Sludge Handling
Sludges are generated by a number of treatment technologies, including equalization, gravity assisted
separation, chemical precipitation, and biological treatment. These sludges are further processed at
landfill sites using various methods. The following sections describe each type of sludge handling
system used within the Landfills industry.
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8.1.4.1 Sludge Slurrying
Sludge slurrying is the process of transporting sludge from one treatment process to another. It only
can be applied to liquid sludges that can be pumped through a pipe under pressure. National
estimates based on EPA's Detailed Questionnaire data indicate that 33 percent of indirect hazardous
landfills and less than one percent of indirect non-hazardous landfills use sludge slurrying systems as
part of their wastewater treatment systems.
8.1.4.2
Gravity Thickening
Gravity thickening, as shown in Figure 8-23, consists of placing the sludge in a unit similar to a
gravity assisted separator, where the sludge is allowed to settle, with the liquid supernatant remaining
at the top. The thickened sludge is then removed, and the separated liquid is returned to the
wastewater treatment system for further treatment. Usually sludges that contain two to three percent
solids can be thickened to approximately five to ten percent solids using gravity thickening. National
estimates based on the Detailed Questionnaire responses show that 67 percent of indirect hazardous
landfills, 4 percent of indirect non-hazardous landfills, and 8 percent of direct non-hazardous landfill
facilities employ gravity thickening as part of their wastewater treatment systems.
8.1.4.3
Pressure Filtration
Plate and frame pressure filtration systems are used at landfill facilities to dewater sludges from
physical/chemical and biological treatment processes. Sludges generated at a total solids
concentration of two to five percent by weight are dewatered to a 30 to 50 percent solids mass using
plate and frame filtration (see reference 3). Sludges from treatment systems can be thickened by
gravity or stabilized prior to dewatering by pressure filtration "or may be processed directly with the
plate and frame filtration unit.
A pressure filter consists of a series of screens (see Figure 8-24) upon which the sludge is applied
under pressure. A precoat material may be applied to the screens to aid in solids removal. The
applied pressure forces the liquid through the screen, leaving the solids to accumulate behind the
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screen. Filtrate which passes through the screen media is recirculated back to the head of the on-site
wastewater treatment plant. Screens (also referred to as plates) are held by frames placed side by side
and held together with a vice-type mechanism. The unit processes sludge until all of the plates are
filled with dry sludge as indicated by a marked rise in the application pressure. Afterwards, the vice
holding the plates is loosened and the frames separated. Dried sludge is manually scraped from the
plates and collected in a hopper for final disposal. The size of the filter and the number of plates
utilized depends not only on the amount of solids produced by treatment processes, but also is highly
dependent on the desired operational requirements for the filter. A plate and frame filter can produce
a drier sludge than possible with most other methods of sludge dewatering. It is usually not operated
continuously, but offers operational flexibility since it can be operated in a batch mode.
Pressure filtration is the most common method of sludge dewatering used at landfill facilities.
National estimates indicate that 67 percent of indirect hazardous landfills, 5 percent of indirect non-
hazardous landfills, and 8 percent of direct non-hazardous landfill faculties use pressure filtration
systems as part of their wastewater treatment systems.
8.1.4.4
Sludge Drying Beds
Sludge drying beds are an economical and effective means of dewatering sludge when land is
available. Sludge may be conditioned by thickening or stabilization prior to application on the drying
beds, which are typically made up of sand and gravel. Sludge is placed on the beds in an 8 to 12 inch
layer and allowed to dry. The drying area is partitioned into individual beds, approximately 20 feet
wide by 20 to 100 foot long (see reference 13), or a convenient size so that one or two beds will be
filled by the sludge discharge from other sludge handling units or sludge storage facilities. The outer
boundaries may be constructed with concrete or earthen embankments for open beds. Open beds
are used where adequate area is available and sufficiently isolated to avoid complaints caused by
odors. Covered beds with greenhouse types of enclosures are used when it is necessary to dewater
sludge continuously throughout the year regardless of the weather and where sufficient isolation does
not exist for the installation of open beds.
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Sludge is dried by drainage through the sludge mass and supporting sand and by evaporation from
the surface exposed to the air. Most of the water leaves the sludge by drainage; thus, the provision
of an adequate underdrainage system is essential. Drying beds are equipped with lateral drainage tiles
that should be adequately supported and covered with coarse gravel or crushed stone. The sand layer
should be from 9 to 12 inches deep (see reference 13) with an allowance for some loss from cleaning
operations. Water drained from the sludge is collected and typically recirculated back to the on-site
wastewater treatment system. Sludge can be removed from the drying bed after it has drained and
dried sufficiently. The moisture content is approximately 60 percent after 10 to 15 days under
favorable conditions (see reference 13). Dried sludge is manually removed from the beds and sent
for on-site or off-site disposal. Figure 8-25 depicts the cross section of a typical drying bed.
8.1.5 Zero Discharge Treatment Options
In this section, additional treatment processes and disposal methods associated with zero or
alternative discharge at landfill facilities are described. Based on the responses to the Detailed
Questionnaire, national estimates indicate that 27 percent of all non-hazardous landfill facilities and
96 percent of all hazardous landfill facilities use zero discharge treatment options. The most
commonly used zero discharge treatment method employed by these facilities is land application and
recirculation. This section describes land application, recirculation, deep well disposal, evaporation,
solidification, and off-site disposal.
Land application involves the spreading of the wastewater over an area of land that is capped, closed,
or an unused portion of a landfill. The land generally has sufficient percolation characteristics to
allow the water to drain adequately into the soil. .The area is assessed to insure that the soil can
provide adequate biological activity to cause the degradation of organic pollutants and also to provide
sufficient binding of any metals present.
Recirculation involves the spraying of recycled landfill leachate over areas of a landfill. Although this
process promotes biodegradation and evaporation of the leachate volume, recirculation is primarily
used as a means of dust control.
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Deep well disposal consists of pumping the wastewater into a disposal well, that then discharges the
liquid into a deep aquifer. Normally, these aquifers are thoroughly characterized to insure that they
are not hydrogeologically connected to a drinking water supply. The characterization requires the
confirmation of the existence of impervious layers of rock above and below the aquifer.
Traditionally used as a method of sludge dewatering, evaporation, or solar evaporation, also can
involve the discharge and ultimate storage of wastewater into a shallow, lined, on-site ditch. Since
the system is open to the atmosphere, the degree of evaporation is greatly dependent upon climatic
conditions.
Solidification is a process in which materials, such as fly ash, cements, and lime, are added to the
waste to produce a solid. Depending on both the contaminant and binding material, the solidified
waste may be disposed of in a landfill.
Some facilities that have a low leachate generation rate (either because of arid conditions or through
capping), transport their wastewater off site to either another landfill facility's wastewater treatment
system or to a Centralized Wastewater Treatment (CWT) facility for ultimate disposal.
8.2
Treatment Performance
This section presents an evaluation of performance data on treatment systems collected by EPA
during field sampling programs. The results of these EPA sampling episodes assisted the Agency in
evaluating the various types of treatment technologies. For those facilities employing the selected
technologies, the sampling data were used to develop the effluent limitations. A more detailed
discussion of the development of effluent limitations can be found in Chapter 11.
8.2.1
Performance of EPA Sampled Treatment Processes
To collect data on potential BAT treatment technologies, Detailed Questionnaire responses were
reviewed to identify candidate facilities that had well-operated and designed wastewater treatment
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systems. EPA conducted 19 site visits to 18 facilities to evaluate treatment systems. Based on these
site visits, a total of six facilities were selected for EPA sampling which consisted of five consecutive
days of sampling raw influent wastewaters, and intermediate and effluent points in the wastewater
treatment system. One of these week-long episodes (4690) was conducted at a facility that was
eventually excluded from the proposed regulations because it was a captive landfill. In addition, the
only technology sampled at this facility primarily treated contaminated groundwater. The data
collected during this sampling episode were not used in selection of pollutants of interest and in the
calculation of effluent limitations and therefore, is not discussed further hi this section. For the
remaining five selected sampling facilities in both the Non-Hazardous and Hazardous subcategories,
EPA collected data on a variety of biological and chemical treatment processes. Technologies
evaluated at the selected sampling facilities include hydroxide precipitation, activated sludge,
sequencing batch reactors, multimedia filtration and reverse osmosis. Table 4-2 in Chapter 4,
presents a summary of the treatment technologies sampled during each EPA sampling episode.
•>
Summaries of the treatment system performance data collected by EPA during each of these sampling
episodes that were used in the development of the proposed effluent limitations guidelines and
standards are presented below.
8.2.1.1
Treatment Performance for Episode 4626
EPA performed a week-long sampling program during episode 4626 to obtain performance data on
several treatment technologies including hydroxide precipitation, biological treatment using anaerobic
and aerobic biotowers and multimedia filtration. A flow diagram of the landfill wastewater treatment
system sampled during episode 4626 is presented in Figure 8-26. The wastewater treatment system
used at this Subtitle D municipal facility treats predominately landfill generated wastewaters, including
gas condensate. Table 8-2 presents a summary of percent removal data collected at episode 4626 for
the performance of the biological treatment system and for the entire treatment system, excluding the
multimedia filtration system used to polish the discharge from the effluent holding tank. Percent
removal efficiencies for the processes were calculated by first obtaining an average concentration
based upon the daily sampling results for each sample collection location (influent and effluent point
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to the treatment process). Next, the percent removal efficiency of the system was calculated using
the following equation:
Percent Removal = [Influent Concentration - Effluent Concentration] xlOO
Influent Concentration
Negative percent removals for a treatment process were reported on the table as 0.0 percent
removals.
The treatment efficiency of the biological treatment system was determined using the data obtained
from sampling points 04 and 07 (see Figure 8-26). As demonstrated on the Table 8-2, the biological
treatment system experienced good overall removals for TOC (93.0 percent), COD (90.85 percent),
and ammonia as nitrogen (99.14 percent). The biological system did not demonstrate high removals
for BOD5 (10.2 percent), TSS (9.32 percent) or for various metals (generally less than 10 percent
removals) because the pollutants were generally not present in the biological treatment system influent
at treatable levels. The system influent BOD5 was 39.2 mg/1, TSS was 1 1 .8 mg/1, and most metals
were not at detectable levels even though the raw wastewater at this facility exhibited a BOD5
concentration of 991 mg/1, TSS of 532 mg/1, and several metals at treatable levels. The biological
treatment system influent was weak because this facility employed large aerated equalization tanks
and a chemical precipitation system prior to biological treatment. The equalization tanks had a
retention time of approximately 15 days and were followed by a chemical precipitation system using
sodium hydroxide. Due to the long retention time and wastewater aeration, significant biological
activity occurred in these tanks. The resulting insoluble pollutants were removed in the primary
clarifier prior to entering the biological towers. Organic pollutant parameters were not detected in
the effluent from the biological treatment process with the exception of 1,4-dioxane at a
concentration of 13.8
To determine the treatment efficiency of the entire treatment system, the influent concentration was
determined by taking a flow-weighted average of the two influent sampling points; sampling points
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01 and 02. Effluent from the treatment system was represented by sample point 07. The entire
treatment system experienced good removals for the following conventional and nonconventional
pollutants parameters; BOD5, TSS, ammonia as nitrogen, COD, TOG, and total phenols. Each of the
organic pollutant parameters identified in the influent to the treatment system was removed to non-
detectable levels, with the exception of 1,4-dioxane which still experienced a high percent removal
(94.2 percent). Most metals had good percent removals or were removed to non-detectable levels.
8.2.1.2
Treatment Performance for Episode 4667
EPA performed a week-long sampling program during episode 4667 to obtain performance data on
various treatment units, including ammonia removal, hydroxide precipitation, biological treatment
using a sequencing batch reactor, granular activated carbon adsorption and multimedia filtration. A
flow diagram of the landfill wastewater treatment system sampled during episode 4667 is presented
in Figure 8-27. The wastewater treatment process used at this Subtitle D non-hazardous facility
primarily treats landfill generated wastewaters and a small amount of sanitary wastewater flow from
the on-site maintenance facility. Table 8-3 presents a summary of percent removal data collected
during episode 4667 for the biological treatment system (SBR) and for the entire treatment system.
The treatment efficiency of the biological treatment system was determined using the data obtained
from sampling points 03 and 04 (see Figure 8-27). As demonstrated on Table 8-3, the SEP. treatment
system experienced moderate overall removals for TOC (43.4 percent), COD (24.7 percent), and
BOD5 (48.7 percent). Improved removal efficiencies were observed for TSS (82.9 percent), total
phenols (74.2 percent), and ammonia as nitrogen (80.7 percent). Metals, such as barium, chromium,
and zinc, had low removal efficiencies. However, as noted for the previous facility, these metals
were observed in the influent to the biological system at low concentrations, near or close to expected
effluent levels. Other metals also had poor removal efficiencies including boron and silicon. Non
of the organic parameters were detected in the effluent from the SBR treatment process.
The treatment efficiency of the entire treatment system at the facility was determined using the data
obtained from sampling points 01 and 06 (see Figure 8-27). Overall the treatment system
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experienced good removals for BOD5, TSS, ammonia as nitrogen, COD, TOC and total phenols.
Each of the organic pollutants detected in the influent were removed to non-detectable levels in the
effluent. Also, each of the metal parameters experienced a good removal rate through the treatment
system.
8.2.1.3 Treatment Performance for Episode 4721
EPA performed a week-long sampling program during episode 4721 to obtain performance data on
the SBR treatment process installed at this Subtitle C hazardous facility. A flow diagram of the landfill
wastewater treatment system sampled during episode 4721 is presented hi Figure 8-28. The
wastewater treatment process used at this facility treats predominately landfill generated wastewaters.
The majority of the landfill wastewater was generated by Subtitle D non-hazardous landfills.
However, the facility also commingled wastewater generated by an on-site hazardous waste landfill
for treatment. Limited amounts of off-site generated wastewaters also are treated at the on-site
treatment plant, primarily from another landfill facility operated by the same entity. Table 8-4
presents a summary of percent removal data collected during episode 4721 for the SBR treatment
system.
The treatment efficiency of the biological treatment system was determined using the data obtained
from sampling points 01 and 02 (see Figure 8-28). As demonstrated on the Table 8-4, the SBR
treatment system experienced good overall removals for a number of convention/nonconventional and
organic parameters; including total phenols, BOD5, aniline, benzoic acid, 2-propanone, 2-butanone,
naphthalene, alpha-terpineol, ethylbenzene, p-cresol, m-xylene, 4-methyl-2-pentanone, toluene,
phenol, hexanoic acid, and ammonia as nitrogen. All of the organic parameters were observed in the
influent were removed to non-detectable levels in the effluent. COD and TOC percent removals were
observed at 72.2 and 66.3 percent, respectively. The percent removal for TSS was 72.1 percent.
Metals with quantitative percent removals include arsenic (61.9 percent), chromium (46.3 percent),
copper (61.2 percent), and zinc (66.3 percent).
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8.2.1.4 Treatment Performance for Episode 4759
EPA performed a week-long sampling program during episode 4759 to obtain performance data on
various treatment processes installed at this Subtitle C hazardous facility; including chemical
precipitation using ferric chloride and sodium hydroxide and biological treatment using an activated
sludge process. A flow diagram of the landfill wastewater treatment system sampled during episode
4759 is presented in Figure 8-29. The wastewater treatment process used at this facility treats
predominately landfill generated wastewaters, but also handles limited amounts of contaminated storm
water from storage containment systems. Table 8-5 presents a summary of percent removal data
collected at episode 4759 for the biological treatment system only and for the entire treatment system
(combined chemical precipitation and biological treatment processes).
The treatment efficiency of the biological treatment system was determined using the data obtained
from sampling points 02 and 03 (see Figure 8-29). As demonstrated on the Table 8-5, the biological
treatment system experienced good overall removals for a number of conventional/nonconventional
and organic parameters; including BOD5, COD, TOC, total phenols, aniline, benzoic acid, 2,4-
dimethylphenol, 2-propanone, methylene chloride, 2-butanone, benzyl alcohol, isobutyl alcohol, o-
cresol, p-cresol, 4-methyl-2-pentanone, phenol, pyridine, toluene and hexanoic acid. Most of the
organic parameters detected in the influent were removed to non-detectable levels in the effluent from
the biological treatment system. Most of the metal parameters, such as chromium, copper, selenium,
titanium, and zinc, were observed at low concentrations in the influent to the biological treatment
system and therefore did not demonstrate good percent removals.
The treatment efficiency of the entire treatment system at the facility was determined using the data
obtained from sampling points 01 and 03 (see Figure 8-29). As demonstrated on Table 8-5, the
entire treatment system experienced good overall removals for a number of
convention/nonconventional and organic parameters; including total phenols, BOD5, 2,4-
dimethylphenol, aniline, benzene, benzoic acid, 2-propanone, methylene chloride, 2-butanone, benzyl
alcohol, isobutyl alcohol, o-cresol, p-cresol, 4-methyl-2-pentanone, phenol, pyridine, toluene,
tripropyleneglycol methyl ether and hexanoic acid. Most of the organic parameters detected in the
8-48
-------
influent were removed to non-detectable levels in the effluent. COD and TOC percent removals were
observed at 76.4 percent and 84.2 percent, respectively. Ammonia as nitrogen and TSS had poor
removal rates of 25.7 percent and 26.6 percent, respectively. Metals with quantitative percent
removals include arsenic (46.6 percent), chromium (80.2 percent), copper (45.2 percent), strontium
(66.8 percent), titanium (89.6 percent), and zinc (62.5 percent). Pesticide/herbicide parameters such
as 2,4-DB, dicamba and dichloroprop had good removal efficiencies through the treatment system.
Dioxin/furan parameters were not detected in either the influent or effluent samples.
8.2.1.5 Treatment Performance for Episode 4687
EPA performed a week-long sampling program during episode 4687 to obtain performance data on
the reverse osmosis treatment process installed at this Non-Hazardous Subtitle D facility. A flow
diagram of the landfill wastewater treatment system sampled during episode 4687 is presented in
Figure 8-30. The wastewater treatment process used at this facility treats on-site landfill generated
wastewaters. Table 8-6 presents a summary of percent removal data collected at episode 4687 for
a single-pass reverse osmosis unit including the multi-media filtration unit and the entire treatment
system consisting of a second pass RO unit.
The treatment efficiency of the single-pass reverse osmosis treatment system at the facility was
determined using the data obtained from sampling points 01 and 02 (see Figure 8-30). As
demonstrated on Table 8-6, the single-pass reverse osmosis treatment system experienced good
overall removals for a number of conventional/nonconventional and organic parameters; including
TSS, TOC, BOD5, TDS, COD, 4-methyl-2-pentanone, alpha-terpineol, benzoic acid,
tripropyleneglycol methyl ether, and hexanoic acid. A number of other organic parameters also were
observed to have been removed by the treatment process at various levels lower than 95 percent.
Total phenols and ammonia nitrogen percent removals were observed at 75.1 and 76.7 percent,
respectively. Metals with quantitative percent removals include arsenic (87.4 percent), boron (54.1
percent), silicon (88.3 percent) and strontium (92.9 percent). All of the pesticide/herbicide
parameters detected in the influent, including 2,4,5-TP, 2,4-D, 2,4-DB, dicamba, dichlorprop, MCPA
and MCPP, were removed to non-detectable levels.
8-49
-------
The treatment efficiency of the entire treatment system at the facility was determined using the data
obtained from sampling points 01 and 03 (see Figure 8-30). The additional polishing reverse osmosis
unit caused the removal efficiency of most of the conventional and nonconventional parameters to
increase. These parameters include BOD5, ammonia as nitrogen, COD, TDS, TOC and total phenols.
The removal efficiency of several organic parameters were observed to increase from the single-pass
treatment system including 2-butanone, 2-propanone, phenol, p-cresol and toluene. Boron percent
removal also increased from 54.1 percent in the single-pass reverse osmosis system to 94.4 percent
in the two-stage reverse osmosis treatment system.
8-50
-------
Table 8-1: Wastewater Treatment Technologies Employed at In-Scope Landfill Facilities
(Percent of Landfills Industry)
Treatment Technology
Equalization
Neutralization
Physical/chemical oxidation
Chemical precipitation
Adsorption
Filtration
Stripping
Biological treatment
Gravity assisted separation
Sludge preparation
Sludge dewatering
Subtitle D Non-Hazardous
Direct
Discharge
23.4
7.0
10.1
11.4
1.3
9.5
3.8
29.1
32.3
3.2
12.7
Indirect
Discharge
11.2
6.6
0.5
5.3
1.3
1.4
1.3
3.7
8.5
0.5
5.0
Subtitle C
Hazardous
Indirect
Discharge
0.0
33.3
33.3
33.3
0.0
0.0
0.0
66.7
66.7
33.3
66.7
8-51
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8-52
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Effluent
Figure 8-2: Neutralization
8-59
-------
CoagiiaTt
Influent-
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8-60
-------
100
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Figure 8-4: Calculated Solubilities of Metal Hydroxides
8-61
-------
Wastewater
Influent
Chemical Precipitation Tank
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8-62
-------
Caustic Feed
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8-63
-------
Su If uric
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Effluent
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8-64
-------
Wastewater
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Air
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8-65
-------
Coarse Media
Finer Media
Finest Media
Support
Underdrain Chamber
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I
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Silica Sand
Garnet
Gravel
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->- Backwash
Backwash
Figure 8-9: Multimedia Filtration
8-66
-------
Permeate (Treated Effluent)
Wastewater
Feed
Concentrate
Membrane Cross-section
Figure 8-10: Ultrafiltration System Diagram
8-67
-------
Concentrate
Feed
Membrane
Figure 8-11: Tubular Reverse Osmosis Module
8-68
-------
Fresh
Carbon
Fill
Collector/
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Carbon
Discharge
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Backwash
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Treated
Effluent
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8-69
-------
Wastewater
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Used
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Treated
Effluent
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8-70
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Surface Aerators
Figure 8-14: Aerated Lagoon
8-71
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Gas Exchange
Figure 8-15: Facultative Pond
8-72
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8-74
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Figure 8-18: Trickling Filter
8-75
-------
Inoculum ~
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Waslcwater Influent -
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Effluent
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8-76
-------
Air
Wastewater
Influent
Secondary Clarifier
(side view)
Recycle Sludge
Waste
Excess Sludge
Figure 8-20: Activated Sludge System
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Figure 8-21: Powder Activated Carbon Treatment System
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React
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Figure 8-22: Sequencing Batch Reactor Process Diagram
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Chemical Precipitation
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Supernatant
Settling
Zone
Supernatant
Thickened Sludge to Contract Haul
or to Sludge Dewatering
(-5% solids)
Figure 8-23: Gravity Thickening
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Influent
Filtrate
Filter Cloth
Filter Cake
Plate Assembly
Figure 8-24: Plate and Frame Pressure Filtration System Diagram
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Coarse Sand
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Figure 8-25: Drying Bed
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9.0 ENGINEERING COSTS
This chapter presents the costs estimated for compliance with the proposed effluent limitations
guidelines and standards for the Landfills industry. Section 9.1 provides a discussion of the cost
estimation methodologies considered by EPA including evaluation of two cost estimation models.
Section 9.2 presents a discussion of the types of cost estimates developed, while in Section 9.3, the
development of capital costs, operating and maintenance (O&M) costs and other related costs is
described in detail. Section 9.4 summarizes the compliance costs for each regulatory option
considered by EPA.
9.1
Evaluation of Cost Estimation Techniques
This section presents a discussion of the cost estimation techniques considered by EPA, including
evaluation of two cost estimation models. The criteria used by EPA to evaluate these techniques as
well as the results of a benchmark analysis to compare the accuracy of these techniques are presented.
The selected cost estimation techniques also are presented.
9.1.1
Cost Models
Development of compliance cost estimates for leachate treatment systems is required to determine
the economic impact of the regulation. EPA has identified existing cost estimation models to
facilitate the development of compliance cost estimates. In a mathematical cost model, various design
and vendor data on a variety of treatment technologies are combined and cost equations that describe
costs as a function of system parameters, such as flow, are developed for each treatment technology.
Using these types of models allows for the generation of compliance cost estimates for several
regulatory options that are based on the iterative addition of treatment technologies which can assist
EPA in the selection of options as the basis for the proposed regulations.
Two well known cost models were evaluated for use in developing costs:
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• Computer-Assisted Procedure for the Design and Evaluation of Wastewater
Treatment Systems (CAPDET), developed by the U.S. Army Corps of Engineers.
WAV Costs Program (WWC), Version 2.0, developed by CWC Engineering
Software.
CAPDET is intended to provide planning level cost estimates to analyze alternatives in the design of
wastewater treatment systems. Modules are used to develop cost estimates for a variety of physical,
chemical, and biological treatment unit processes and can be linked together to represent entire
treatment trains. Equations in each of these modules are based upon common engineering principles
used for wastewater treatment system design. The CAPDET algorithm generates a design based on
input parameters selected by the user, calculates cost estimates for various treatment trains and ranks
them based on present worth, capital, operating, or energy costs.
The WWC cost model was developed by Culp/Wesner/Culp from a variety of engineering sources,
including vendor supplied data, actual plant construction data, unit takeoffs from actual and
conceptual designs, and published data. The model calculates cost estimates for a variety of
individual treatment technology units that can be combined together to develop compliance cost
estimates for the complete treatment systems. The WWC model does not design each treatment
technology unit but rather prompts the user to provide design input parameters that form the basis
for the cost estimate. The WWC model includes a separate spreadsheet program that provides design
criteria guidelines to assist in developing the input parameters to the cost estimating program. The
spreadsheet includes treatment component design equations and is supplied with default parameters
that are based upon accepted design criteria used in wastewater treatment, to assist in the design of
particular treatment units. The spreadsheet also is flexible enough to allow selected design parameters
to be modified to estimate industry-specific factors accurately. Once design inputs are, entered into
the program, the WWC model calculates both construction and operation and maintenance (O&M)
costs for the selected wastewater treatment system.
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9.1.2
Vendor Data
For certain wastewater treatment technology units, the cost model was not considered the most
accurate estimate of costs. For these instances, EPA determined that actual equipment and operation
and maintenance costs obtained directly from equipment vendors often can provide accurate cost
estimates.
Information on landfill wastewater characteristics was provided to vendors to determine the
appropriate treatment unit and accurate sizing. Quotes obtained from vendors included equipment
costs that were factored up to total capital costs by the Agency to account for site preparation,
mobilization costs, and engineering contingencies. Vendor quotes also were obtained for operation
and maintenance costs including utility usage and cost. Vendor quotes were used to determine cost
curves for equalization, multi-media filtration, and reverse osmosis. The cost curves used for these
treatment technologies are based on direct vendor quotes, commercial costing guides, or cost
information developed from vendor quotes as part of the Centralized Waste Treatment (CWT)
effluent guidelines effort.
9.1.3
Other EPA Effluent Guideline Studies
Other EPA effluent studies, such as the Organic Chemicals and Plastics and Synthetic Fibers (OCPSF)
industry effluent guidelines, were reviewed to obtain additional costing background and supportive
information. However, costs developed as part of other industrial effluent guidelines are not used
in costing for this industry, with the exception of the CWT effluent guideline data referenced in
Section 9.1.2.
9.1.4
Benchmark Analysis and Evaluation Criteria
A benchmark analysis was performed to evaluate the accuracy of each cost estimation technique. This
benchmark analysis used actual costs provided in the 308 Questionnaires and compared them to costs
generated each cost estimation technique. Four landfill facilities (Questionnaire ID numbers (QIDs)
16122,16125,16041, and 16087) with wastewater treatment systems that were considered as a basis
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for BPT/BATVNSPS/PSES/PSNS limitations were selected by EPA for benchmarking. Cost
estimates were developed for wastewater treatment units that make up the treatment systems at these
landfill facilities using the WWC and CAPDET models and vendor quotes. Next, EPA compared
these cost estimates to the actual component costs provided in the 308 Questionnaires to evaluate
the accuracy of each methodology in estimating capital and operation and maintenance costs. This
cost comparison is presented in Table 9-1. Treatment technologies that were used in this benchmark
analysis include:
• equalization,
• chemical precipitation,
• activated sludge,
• sedimentation, and
• multi-media filtration.
EPA also benchmarked cost estimates developed using these techniques against actual costs for
wastewater treatment systems that included equalization, chemical precipitation, and multi-media
filtration, that were obtained from industrial waste combustor facilities as part of that effluent
guidelines effort. EPA believes that the wastewater characteristics being treated by these treatment
systems, i.e., inorganic contaminants and solids in an uncomplexed matrix, are similar for both
landfills and industrial waste combustor facilities and that this additional comparison provides a more
thorough evaluation of the Agency's cost estimation methodologies. Table 9-2 presents a comparison
of the capital and O&M costs obtained for the wastewater treatment systems at four industrial waste
combustor facilities to the cost estimates obtained using each technique, i.e., the WWC and CAPDET
models, and vendor quotes.
As shown in Tables 9-1 and 9-2, EPA has determined that, based on the results of the benchmark
analyses for both data sources, the WWC model generated cost estimates that are considered more
accurate than the CAPDET model when compared to actual treatment technology costs as provided
in 308 Questionnaire responses. In all instances, the WWC model estimated the more accurate
treatment system capital and O&M costs as compared to CAPDET and vendor costs. For several
facilities, such as QIDs 16087,16122, and 16125, the WWC model generated capital costs to within
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approximately 32 percent of costs provided in the questionnaires. O&M costs for several facilities,
including QIDs 16041, 16087, and 16122, were estimated to within approximately 18 percent of
costs provided in the 308 Questionnaires.
EPA used the following criteria to evaluate each cost estimation technique and to select the
appropriate option for developing a methodology for estimating compliance costs for the Landfills
industry:
Does the model contain costing modules representative of the various
wastewater technologies in use or planned for use in the Landfills industry?
• Can the model produce costs in the expected flow range experienced in this
industry?
Can the model be adapted to cost entire treatment trains used in the Landfills
industry?
• Is sufficient documentation available regarding the assumptions and sources
of data so that costs are credible and defensible?
• Is the model capable of providing detailed capital and operation and
maintenance costs with unit costing breakdowns?
Is the model capable of altering the default design criteria in order to accurately
represent actual design criteria indicative of the Landfills industry?
9.1.5
Selection of Final Cost Estimation Techniques
Based upon the results of the benchmark analysis, the WWC model was selected for estimating costs
for the majority of the treatment technologies that form the basis for BPT/BAT/NSPS/PSES/PSNS
effluent limitations and standards. It was determined that the "WWC model is capable of producing
accurate capital and O&M costs for a wide range of treatment technologies. The CAPDET model
was not considered capable of generating cost estimates for many of the technologies that form the
basis for BPT/BAT/NSPS/PSES/PSNS effluent limitations and standards for the Landfills industry
and was determined not to. be as accurate in estimating technology costs for landfill facilities.
Therefore, EPA decided not to use the CAPDET model for estimating compliance costs.
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It was determined that the WWC model best satisfies the selection criteria. The program can estimate
costs for a wide range of typical and innovative treatment technologies and can combine these costs
of each technology to develop system costs. Since the WWC model is a computer based program,
it readily allows for the iterative development of costs for a number of facilities and regulatory
options. The program utilizes cost modules that can accommodate the range of flows and design
input parameters needed to develop cost estimates for landfill facilities. Cost estimates generated by
this model are based upon a number of sources, including actual construction and operation costs,
as well as published data and are presented in a breakdown summary table that contains unit costs
and totals. Finally, the WWC model can be adapted to estimate costs based upon specified design
criteria and wastewater flow rates.
EPA notes that there were particular technologies for which WWC model did not produce accurate
cost estimates; these technologies included equalization, multi-media filtration, and reverse osmosis.
In low flow situations, costs developed for these treatment technologies were excessively high as
compared to industry provided costs in 308 Questionnaire responses. For these technologies, EPA
determined that vendor quotes provided a more accurate estimate of compliance costs and would be
used in the final engineering costing methodology for these technologies.
9.2 Engineering Costing Methodology
This section presents the costing methodology used to develop treatment costs for BPT, BCT, BAT,
and PSES options for the Landfills industry. This section also presents a description of additional
costs, such as monitoring costs, that were developed by EPA. The following discussion presents a
detailed summary of the technical approach used to estimate the compliance costs for each landfill
facility. Total capital and annual operation and maintenance costs were developed for each facility
in EPA's database to upgrade their existing wastewater treatment system, or to install new treatment
technologies, to comply with the long term averages for each proposed option. Development of the
long term averages is discussed in Chapter 11 of this document and in the Statistical Support
documents. Facilities were costed primarily using the WWC model and on occasion, from cost
curves developed from vendor quotes. Table 9-3 presents a breakdown of the cost estimation method
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used for each treatment technology. Additional costs were developed for monitoring, Resource
Conservation and Recovery Act (RCRA) permit modifications, and residual disposal. Total facility
compliance costs under each proposed BPT, BCT, BAT, and PSES option then were developed by
adding treatment costs with these additional costs. Cost estimates for zero or alternative discharge
facilities were not developed for any of the regulatory options.
9.2.1 Treatment Costing Methodology
The methodology used to develop facility-specific BPT, BCT, BAT, and PSES option compliance
costs is presented graphically on the flow diagram in Figure 9-1. Facilities were costed for an entire
new treatment system, whether or not they had existing treatment at the facility, if the collected flow
subject to this guideline was less than 85 percent of the total facility flow rate.
For each proposed regulatory option, each landfill facility in the Detailed Technical Questionnaire
database was evaluated to determine if the facility would incur costs hi order to comply with the
proposed regulations. EPA compared the current discharge concentrations of the facility's effluent
with the long term averages from each proposed regulatory option. If the facility's current discharge
concentration was less than the long term average, it was considered to be in compliance. A facility
considered to be in compliance was projected to incur costs only for additional monitoring
requirements. If a facility was not in compliance but had treatment unit operations in-place capable
of complying with the proposed long term averages, the facility was costed for system upgrades that
would bring the facility into compliance.
For facilities that did not have BPT, BCT, BAT, or PSES treatment systems or the equivalent, cost
estimates were developed for the additional unit operations and/or system upgrades necessary to meet
each long term average. Facilities that were already close to compliance with the long term averages
only required an upgrade to achieve compliance with proposed limitations for a regulatory option.
Upgrade costs were developed using the WWC model whenever possible, and included either
additional equipment to be installed as part of an existing wastewater treatment system, expansion
of existing equipment, or operational changes. Examples of upgrade costs include such items as new
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or expanded chemical feed systems and improved or expanded aeration systems. If a facility had no
treatment system (or one that could not achieve desired levels with upgrades or minor additions) cost
estimates for an entire BPT, BCT, BAT, or PSES treatment system were developed for that facility.
The first step in using the WWC model was to use the design criteria guidelines spreadsheet to
develop input parameters for the computer program. Actual pollutant loadings from the facility were
used whenever possible. If pollutant loadings were not available for a particular parameter, the
estimates of pollutant concentrations in untreated landfill wastewater were used (see Chapter 6). The
facility's baseline flow rate and the regulatory option long term averages also were used in the design
of the unit operation. Certain parameters such as BOD5, TSS, and ammonia are used directly in the
WWC model and the design criteria guideline spreadsheet to design the various treatment unit
operations. Metals included as pollutants of interest were selected to assist in the design of chemical
precipitation systems. The metals to be treated typically control the type and amount of precipitating
agents, which govern the chemical feed system design. A more detailed discussion of the design
parameters and costs associated with individual treatment technologies is presented hi Section 9.3.
The design parameters from the design criteria spreadsheet then were input in the WWC model to
generate installed capital and O&M costs. O&M costs for treatment chemicals, labor, materials,
electricity, and fuel are included in the WWC model O&M costs. Treatment costs developed using
the WWC model were corrected to 1992 dollars using the Engineering News Record published
indexes. After the installed capital and annual O&M costs were developed for each facility, selected
cost factors, as shown in Table 9-4, were applied to the results to develop total capital and O&M
costs.
To complete the estimation of compliance costs for each regulatory option, cost estimates for other
than treatment component costs were developed. The assessment must take into account other costs
associated with compliance with the proposed effluent limitations guidelines and standards including:
• land,
• residual disposal,
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• RCRA permit modifications, and
• monitoring.
Each of these additional costs are further discussed and defined in the following sections.
Final capital costs were developed for each facility, then amortized using a seven percent interest rate
over 15 years. This annualized capital cost then was added to the annual O&M cost to develop a
total annual cost for each regulatory option.
9.2.1.1
Retrofit Costs
A retrofit cost factor was applied when additional equipment or processes were required for existing
systems. Retrofit costs cover the need for system modifications and components, such as piping,
valves, controls, etc., that are necessary to connect new treatment units and processes to an existing
treatment facility. Retrofit costs were estimated at 20 percent of the installed capital cost of the
equipment.
9.2.2
Land Costs
Land costs were not included in this analysis because EPA has determined that landfills have adequate
land to accommodate additional treatment systems. Typically, the size of the required treatment
system is small when compared to the land areas occupied by landfills. Landfills, as required by
regulation and permit, have buffer zones around the fill areas. New treatment systems, or upgrades
to an existing system, can be installed readily in this buffer zone or elsewhere at the landfill without
the need to acquire new land.
9,2.3
Residual Disposal Costs
For each of the proposed treatment system additions or upgrades, a cost for residual disposal also
was estimated. Two approaches were used: the first addressed facilities with current sludge handling
capabilities, and the second addressed facilities without current sludge handling capabilities. Residual
disposal costs were prepared on an annualized basis and added to the total O&M costs.
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For facilities with sludge handling capabilities, the present solids treatment/dewatering system was
evaluated to determine if it was capable of handling the additional sludge expected to be produced
under a particular regulatory option. For facilities with insufficient capacity to handle the additional
solids loadings, upgrade costs for sludge conditioning and dewatering were developed to account for
the additional solids. For facilities with sufficient solids treatment capability, no additional sludge
treatment costs were provided. For facilities without installed sludge conditioning and dewatering
facilities, cost estimates for a sludge conditioning and dewatering system were developed.
Dewatered sludge is assumed to be disposed of on-site in the landfill. EPA's cost estimate also
includes the costs associated with the handling and transportation of the sludge to the on-site landfill.
9.2.4
Permit Modification Costs
A cost associated with the modification of an existing RCRA Part B permit was included for all
hazardous waste facilities requiring an upgrade or additional treatment processes. Legal,
administrative, public relations, and engineering fees are included in this cost. This cost was added
to the installed capital for the new or modified equipment and ranged from $50,000 to $250,000,
based upon $50,000 for each piece of new or modified equipment.
9.2.5
Monitoring Costs
Costs were developed for the monitoring of treatment system effluent. Costs were developed for
both direct and indirect dischargers and were based upon the following assumptions:
Monitoring costs are based on the number of outfalls through which
leachate/groundwater is discharged. The costs associated with a single outfall is
multiplied by the total number of outfalls to arrive at the total cost for a facility.
Monitoring costs estimated by EPA are incremental to the costs already incurred by
the facility.
The capital costs for flow monitoring equipment are included in EPA's estimates.
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• Sample collection costs (equipment and labor) and sample shipment costs are not
included in EPA's estimates because EPA assumes that the facility is already
conducting these activities as part of its current permit requirements.
Based upon a review of current monitoring practices at landfills, many conventional and
nonconventional parameters, as well as several metals, are already being monitored on a routine basis.
EPA developed monitoring costs based upon BOD5 and TSS monitoring 20 times per month and
weekly monitoring of ammonia and other toxic and nonconventional pollutants. In general, these
frequencies are higher than currently required. Table 9-5 presents the monitoring cost per sample for
the landfill facilities.
9.2.6 Off-Site Disposal Costs
EPA evaluated whether it would be more cost effective for small flow facilities to have their landfill
wastewater hauled off site and treated at a centralized waste treatment facility, as opposed to on-site
treatment. Total annual costs for new or upgraded wastewater treatment facilities were compared
to the costs for off-site treatment at a centralized waste treatment facility. Off-site disposal costs
were estimated at $0.25 per gallon of wastewater treated. Transportation costs were added to the
off-site treatment costs at a rate of $3.00 per loaded mile using an average distance of 250 miles to
the treatment facility. Transportation costs were based upon the use of a 5,000-gallon tanker truck
load. Facilities that treat their wastewaters off site are considered zero or alternative dischargers and
hence do not incur ancillary costs such as residual disposal, monitoring and permit modifications.
EPA then used the lower of the two costs either on-site or off-site treatment. Table 9-6 presents the
facilities that were costed using off-site treatment.
9.3
Development of Cost Estimates for Individual Treatment Technologies
In Chapter 8, EPA identified and described the wastewater control and treatment technologies used
in the Landfills industry and how they were assembled into proposed regulatory options. The
following sections describe how EPA developed cost estimates for each of the treatment technologies
used in tfie proposed regulatory options. Specific assumptions regarding the equipment used, flow
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ranges, input and design parameters, design and cost calculations are discussed for each treatment
technology. Table 9-3, previously referenced, presented the method used to estimate costs for each
of treatment technologies used in the proposed BPT, BCT, BAT, and PSES options. Table 9-7
presents a summary of the cost estimation techniques used to estimate costs for each treatment
technology for the BPT, BCT, BAT, and PSES regulatory options, including the WWC treatment
module numbers.
To facilitate the costing of many facilities, capital and O&M cost curves were developed for specific
technologies and system components. These curves, which represent cost as a function of flow rate
or other system design parameters, were developed using a commercial statistical software package
(Slidewrite Plus Version 2.1). First, costs were developed using the WWC model for each
technology or component using as a design basis, five different flow rates or other system design
parameters (depending upon the governing design parameter). For instance, a technology costed on
the basis of flow would have costs estimated using the WWC model at 0.01 million gallons per day
(MOD), 0.05 MOD, 0.1 MOD, 0.5 MOD, and 1.0 MGD. Ranges for the five selected points were
based upon a review of the flow or technology design parameters for landfill facilities and were
selected to bracket the range from low to high. Next, these five data points (flow/design parameter
and associated cost) were entered into a commercial statistical software program . Cost curves to
model the total capital and O&M costs then were developed by the program using curve fitting
routines. A second order natural log equation format was used to develop all curves. All cost curves
yielded total capital and O&M costs, unless otherwise noted.
9.3.1 Equalization
EPA conducted a review of questionnaire responses to determine the typical hydraulic detention time
for equalization. Based upon of review of industry furnished data, a detention time of 48 hours was
selected.
Equalization costs developed for each regulatory option are based on published price quotes for
storage tanks. These costs were taken from the 1996 Environmental Restoration Unit Cost Book
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published by R.S. Means, Inc. A cost curve as a function of flow was developed from these tank
quotes. Construction costs were based upon published data for an above ground circular steel tank.
Additional costs associated with a wastewater pumping system and diffused aeration to provide
sufficient mixing of tank contents to prohibit settling also were included. The capital cost curve
developed for equalization is presented as Equation 9-1 and is graphically presented in Figure 9-2.
Capital Costs
ln(Y) = 15.177382 + 1.9815471n(X) + 0.157681n(X)2
(9-1)
where:
X = Flow Rate (MOD), and
Y = Capital Cost (1992 $)
The O&M cost for the equation was taken as a function of the capital cost and is based upon 10
percent of the total capital cost per year.
9.3.2
Flocculation
A cost curve was developed for flocculation using the WWC model. WWC unit process 72 was
used. Costs for flocculation were a function of flow at a hydraulic detention time of 20 minutes. The
capital and O&M cost curves developed for flocculation are presented as Equations 9-2 and 9-3:
Capital Costs
ln(Y) = 11.744579 + 0.6331781n(X) - O.OI55851n(X)2
O&M Costs
ln(Y) = 8.817304 + 0.5333821n(X) + 0.0024271n(X)2
(9-2)
(9-3)
where:
X = Flow Rate (MOD), and
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Y = Cost (1992$)
Figures 9-3 and 9-4 graphically present the flocculation capital and O&M cost curves, respectively.
Cost estimates for flocculation basins are based on rectangular-shaped, reinforced concrete structures
with a depth of 12 feet and length-to-width ratio of 4:1. Common wall construction was used where
the total basin volume exceeded 12,500 cubic feet. Vertical turbine flocculators have higher
structural costs than horizontal paddle flocculators because they require structural support above the
basin. Horizontal paddles are less expensive and more efficient for use in larger basins, particularly
when tapered flocculation is practiced. Manufactured equipment costs are based on a G value 80 (G
is the mean temporal velocity gradient that describes the degree of mixing; i.e., the greater the value
of G the greater the degree of mixing). Cost estimates for drive units are based on variable speed
drives for maximum flexibility, and although common drives for two or more parallel basins are often
utilized, the costs are based on individual drives for each basin.
Energy requirements are based on a G value 80 and an overall motor/mechanism efficiency of 60
percent. Labor requirements are based on routine operation and maintenance of 15 minutes/day/basin
(maximum basin volume 12,500 cubic ft.) and a 4 hour oil change every 6 months.
9.3.3 Chemical Feed Systems
The following section presents the methodology used to calculate the chemical addition feed rates
used with each applicable regulatory option. Table 9-8 is a breakdown of the design process used
for each type of chemical feed. Chemical costs were taken from the September 1992 Chemical
Marketing Reporter and are presented in Table 9-9.
For facilities with existing chemical precipitation systems, an evaluation was made to determine if the
system was achieving the regulatory option long term averages. If the existing system was achieving
long term averages, no additional chemical costs were necessary. However, if the facility was not
achieving the long term averages for an option, costs were estimated for an upgrade to the chemical
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precipitation system. First, the stoichiometric requirements were determined to remove each metal
pollutant of interest to the long term average level. If the current feed rates were within the
calculated feed rates, no additional costs were calculated. For facilities currently feeding less than
the calculated amounts, costs were estimated for an upgrade to add additional precipitation chemicals,
such as a coagulant, or expand their existing chemical feed system to accommodate larger dosage
rates.
Facilities without an installed chemical precipitation system were costed for an entire metals
precipitation system. The chemical feed rates used at a particular facility for either an upgrade or a
new system were based upon stoichiometric requirements, pH adjustments, and the buffering ability
of the raw influent.
In the CWT industry guideline, it was determined that the stoichiometric requirements for chemical
addition far outweighed the pH and buffer requirements. EPA determined that 150 percent of the
stoichiometric requirement would sufficiently account for pH adjustment and buffering of the
solution. An additional 50 percent of the stoichiometric requirement was included to react with
metals not on the pollutant of interest list. Finally, an additional 10 percent was added as excess.
Sodium Hydroxide Feed Systems
The stoichiometric requirement for either lime or hydroxide to remove a particular metal is based
upon the generic equation:
Ib
treatment chemical
Maltreatment chemical
year
valence
r
Na/Ca
where, M is the target metal and 3VTW is the molecular weight.
The calculated amounts of sodium hydroxide to remove a pound of each of the selected metal
pollutants of concern are presented in Table 9-10.
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Sodium hydroxide chemical feed system costs were developed for many facilities using the WWC
model. Actual facility loadings were used to establish the sodium hydroxide dosage requirement.
WWC unit process 45 was used to develop capital and O&M costs for sodium hydroxide feed
systems. The capital and O&M cost curves developed for sodium hydroxide feed systems based upon
the calculated dosage are presented as Equations 9-4 and 9-5, respectively.
Capital Costs
ln(Y) = 10.653 - 0.1841n(X) + 0.0401n(X)2
(9-4)
O&M Costs
ln(Y) = 8.508 - 0.04641n(X) + 0.0141n(X)2
(9-5)
where:
X = Dosage Rate (Ib/day), and
Y = Cost (1992$)
Figures 9-5 and 9-6 graphically present the sodium hydroxide feed system capital and O&M cost
curves, respectively.
Cost estimates for a sodium hydroxide feed system estimated using WWC unit process 45 are based
on a sodium hydroxide feed rate of between 10 to 10,000 Ib/day, with dry sodium hydroxi.de used at
rates less than 200 Ib/day, and liquid sodium hydroxide used at higher feed rates.
The WWC model assumes that dry sodium hydroxide (98.9 percent pure) is delivered hi drums and
mixed to a 10 percent solution on site. A volumetric feeder is used to feed sodium hydroxide to one
of two tanks; one for mixing the 10 percent solution, and one for feeding. Two tanks are necessary
for this process because of the slow rate of sodium hydroxide addition due to the high heat of
solution. Each tank is equipped with a mixer and a dual-head metering pump, used to convey the 10
percent solution to the point of application. Pipe and valving is required to convey water to the dry
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sodium hydroxide solution mixing tanks and between the metering pumps and the point of
application.
A 50 percent sodium hydroxide solution is purchased premixed and delivered by bulk transport for
feed rates greater than 200 Ib/day. The 50 percent solution contains 6.38 pounds of sodium
hydroxide per gallon, that is stored for 15 days in fiberglass reinforced polyester (FRP) tanks. Dual-
head metering pumps are used to convey the liquid solution to the point of application, and a standby
metering pump is provided in all systems. The storage tanks are located indoors, since 50 percent
sodium hydroxide begins to crystallize at temperatures less than 54 °F.
Phosphoric Acid Feed Systems
hi the Subtitle C Hazardous subcategory, phosphoric acid is necessary to neutralize the waste stream
and to provide phosphorus to biological treatment systems.
The phosphoric acid feed system was costed using the WWC unit process 46. The amount of
phosphoric acid necessary to provide nutrient phosphorus was determined to be the controlling factor
over the amount required for pH adjustment. A ratio of BOD5 removed to the amount of phosphorus
present in the influent waste stream (100 pounds BOD5 removed to one pound phosphorus) was used
to determine the amount of phosphoric acid to be added as a nutrient feed to biological treatment
system. To allow for solution buffering, 10 percent excess phosphoric acid was added. The capital
and O&M cost curves developed for phosphoric acid feed systems based upon the calculated dosage
are presented as Equations 9-6 and 9-7, respectively.
Capital Costs
ln(Y) = 10.042 - 0.1551n(X) + 0.0491n(X)2
O&M Costs
ln(Y) = 7.772 - 0.0861n(X) + 0.041 ln(X)2
(9-6)
(9-7)
9-17
-------
where:
X = Dosage Rate (gpd), and
Y = Cost (1992$)
Figures 9-7 and 9-8 graphically present the phosphoric acid feed system capital and O&M cost
curves, respectively.
Costs are based on systems capable of metering 93 percent concentrated acid from a storage tank
directly to the point of application. For feed rates up to 200 gpd, the concentrated acid is delivered
in drums and stored indoors. At higher flow rates, the acid is delivered in bulk and stored outdoors
in FRP tanks. Phosphoric acid is stored for 15 days, and a standby metering pump is included for all
installations.
Polymer Feed Systems
WWC unit process 34 was used to cost for polymer feed systems based upon a dosage rate of 2 mg/1.
Although this module estimates costs for a liquid alum feed system, costs generated by this module
were determined to be more reasonable and accurate in developing polymer system costs than the
WWC unit process 43 for polymer feed systems. The capital and O&M unloaded cost curves
developed for polymer feed systems are presented as Equations 9-8 and 9-9, respectively.
Capital Costs
ln(Y) = 10.539595 - 0.137711n(X) + 0.0524031n(X)2
(9-8)
O&M Costs
ln(Y) = 9.900596 + 0.997031n(X) + 0.000191n(X)2
(9-9)
where:
X = Dosage Rate (Ib/hr), and
Y = Cost (1992$)
9-18
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Figures 9-9 and 9-10 graphically present the polymer feed system capital and O&M cost curves,
respectively.
Polymer is stored for 15 days in fiberglass reinforced polyester tanks. For smaller installations, the
tanks are located indoors and left uncovered and for larger installations, the tanks are covered and
vented, with insulation and heating provided. Dual-head metering pumps deliver the polymer from
the storage tank and meters the flow to the point of application. Feed costs include 150 feet of 316
stainless steel pipe, along with fittings and valves for each metering pump. A standby metering pump
is included for each installation.
9.3.4 Primary Clarification
Cost curves were developed for primary clarification using the WWC model. WWC unit process 118
for a rectangular basin with a 12 foot side wall depth was used. Costs for primary clarification were
based upon a function of flow at an overflow rate of 900 gallons per day per square feet tank size.
The capital and O&M cost curves developed for primary clarification are presented as Equations 9-10
and 9-11, respectively.
Capital Costs
ln(Y) - 12.517967 + 0.5756521n(X) + 0.0093961n(X)2
O&M Costs
ln(Y) = 10.011664 + 0.2682721n(X) + 0.002411n(X)2
(9-10)
(9-11)
where:
X = Flow Rate (MOD), and
Y = Cost (1992 $)
Figures 9-11 and 9-12 graphically present the primary clarification capital and O&M cost curves,
respectively.
9-19
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Estimated costs are based on rectangular basins with a 12 feet side water depth (SWD) and chain and
flight sludge collectors. Costs for the structure assumed multiple units with common wall
construction and include the chain and flight collector, collector drive mechanism, weirs, the
reinforced concrete structure complete with inlet and outlet troughs, a sludge sump, and sludge
withdrawal piping. Yard piping to and from the clarifier is not included in the cost estimates.
9.3.5 Activated Sludge Biological Treatment
Costs for biological treatment systems using the activated sludge process were estimated using the
WWC unit process 18 for a rectangular aeration basin with an 10 foot SWD. Basin size was
determined using a 24 hour hydraulic detention time. Basin volume was calculated using Equation
9-12.
X = ((24 Hours x 3600) x (Z))/l,000
(9-12)
where:
X = Basin Volume (1,000 cu ft)
Z = Flow Rate (cfs)
The WWC model assumes zero O&M costs for the aeration basins only. The unloaded (without
engineering cost factors applied) capital cost curve developed for aeration basins with an 10 foot
SWD is presented as Equation 9-13.
m(Y) = -1.033901 + 3.7226931n(X) - 0.1970161n(X)2
(9-13)
where:
X = Basin Volume (in thousands of cubic feet), and
Y = Capital Cost (1992 $)
Figure 9-13 graphically presents the aeration basin capital cost curve.
9-20
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Aeration using diffused air was costed for the basin using WWC unit process 26 and actual facility
loading conditions. Aeration requirements were calculated using the facility BOD5 and ammonia
loadings and was determined using Equation 9-14.
X = ((A + B)/0.075 x C x 0.232 x 1440)71,000 (9-14)
where:
X = Air Requirement (1,000 standard cubic feet per minute [scfm])
A = BOD5 to Aeration Basin (Ib/day) based on 1.8 Ib O2 /lb BOD5 influent
B = Ammonia to Aeration Basin (Ib/day) based on 4.6 lb O2/lb ammonia influent
C = Transfer Efficiency at 9 percent
The unloaded capital and O&M cost curves developed for air diffusion systems are presented as
Equations 9-15 and 9-16, respectively.
Capital Costs
ln(Y) = 11.034417 + 0.9929851n(X) - 0.00252 lln(X)2 (9-15)
O&M Costs
ln(Y) = 9.497546 + 0.5497151n(X) - 0.0042161n(X)2 (9-16)
where:
X = Air Requirement (1,000 scfm), and
Y = Cost (1992$)
Figures 9-14 and 9-15 graphically present the air diffusion system capital and O&M cost curves,
respectively.
9-21
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The costs for aeration basins include all equipment, piping, electrical, and labor for installation. The
air supply system costs include piping from air source to aeration basin, blowers, controls, and
housing. Aeration basin cost estimates include excavation, concrete walkways, in-basin process
piping, and handrails and attendant costs, but excludes the cost of aeration equipment, electrical and
instrumentation work. EPA considered providing for heated aeration basins for facilities located in
cold weather climates. Based upon data collected by EPA, biological treatment of landfill generated
wastewater was not adversely affected by climate conditions.
9.3.6
Secondary Clarification
Cost curves were developed for secondary clarification using the WWC model. WWC unit process
118 for a rectangular basin with a 12 foot side wall depth, and chain and flight collectors was used.
Costs for secondary clarification were based upon a function of flow, at an overflow rate of 900
gallons per day per square feet tank size. The capital and O&M cost curves developed for secondary
clarification are presented as Equations 9-17 and 9-18, respectively.
Capital Costs
ln(Y) = 12.834601 + 0.6886751n(X) + 0.0354321n(X)2
(9-17)
O&M Costs
ln(Y) = 10.197762 + 0.3399521n(X) + 0.0158221n(X)2
(9-18)
where:
X = Flow Rate (MOD), and
Y = Cost (1992 $)
Figures 9-16 and 9-17 graphically present the secondary clarification capital and O&M cost curves,
respectively.
9-22
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Costs for the structure assumed multiple units with common wall construction, and include the chain
and flight collector, collector drive mechanism, weirs, the reinforced concrete structure complete with
inlet and outlet troughs, a sludge sump, and sludge withdrawal piping. Yard piping to and from the
clarifier is not included in the cost estimates.
9.3.7
Multimedia Filtration
Cost curves as a function of flow rate were developed for a multi-media filtration system using vendor
supplied quotes. The cost curves were developed as part of the CWT effluent guidelines effort. The
capital and O&M cost curves developed for multi-media filtration are presented as Equations 9-19
and 9-20, respectively.
Capital Costs
ln(Y) = 12.265 + 0.6581n(X) + 0.0361n(X)2 (9-19)
O&M Costs
ln(Y) =• 10.851 + 0.1681n(X) + 0.0181n(X)2 (9-20)
where:
X = Flow Rate (MOD), and
Y = Cost (1992$)
Figures 9-18 and 9-19 graphically present the multi-media filtration capital and O&M cost curves,
respectively.
The total capital costs for the multi-media filtration systems represent equipment and installation
costs. The total construction cost includes the costs of the filter, instrumentation and controls,
pumps, piping, and installation. The operation and maintenance costs include energy usage,
maintenance, labor, and taxes and insurance. Energy costs include electricity to run the pumps,
9-23
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lighting, and instrumentation and controls. The labor requirement for ihe multi-media filtration
system was four hours per day.
9.3.8
Reverse Osmosis
Capital and O&M cost curves as a function of flow rate were developed for reverse osmosis
treatment using vendor supplied quotes. Costs were based on one single-pass system using disk tube
module technology. The capital cost curve developed for reverse osmosis is presented as Equation
9-21.
= 14.904 - 0.01421n(X) - 0,06871n(X)2
(9-21)
where:
X = Flow Rate (MOD), and
Y = Capital Cost (1992 $)
Figure 9-20 graphically presents the reverse osmosis capital cost curves. Based upon vendor supplied
costs, O&M costs were taken at $0.02/gallon.
Costs for a standard reverse osmosis system generally include the following components: filter
booster pump, sand or carbon filter, cartridge filter, high-pressure pump and control system, reverse
osmosis module permeators, pure water deacidification filter, inbuilt closed circuit cleaning system,
automatic pure water membrane flushing system, power and control system with microprocessor, full
instrumentation and measurement equipment, comprehensive fail-safe system, fault indication, and
modular skid frame construction. The costs did not take into account the following optional
equipment: main raw-water supply pump, pure water tank and distribution pump, chlorine dosing
system, ultra-violet disinfection system, containerized/mobile systems, self contained power supply,
and anti-magnetic systems.
9-24
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9.3.9
Sludge Dewatering
Costs estimated for sludge dewatering were based upon sludge drying beds. Each facility was costed
separately using the WWC unit process 128. Required bed area was based upon influent
characteristics at a loading of 15 gallons per day of sludge per square foot bed area. Drying bed area
was calculated using Equation 9-22.
X = (A x 365)/B
(9-22)
where:
X = Area (sq ft)
A = Total Dry Solids (Ib/day) based on 0.8 Ib solids/lb BOD5 influent
B = 15 Ib per year sludge/sq ft
The unloaded capital and O&M cost curves developed for sludge drying beds are presented as
Equations 9-23 and 9-24, respectively.
Capital Costs
ln(Y) = 4.488639 + 0.7164711n(X) + 0.0000053 llln(X)2
(9-23)
O&M Costs
ln(Y) = 6.95049 + 0.331551n(X) + 0.0028821n(X)2
(9-24)
where:
X = Area (sq ft), and
Y = Cost (1992$)
Figures 9-21 and 9-22 graphically present the sludge drying bed capital and O&M cost curves,
respectively.
9-25
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Included in the costs are sludge distribution piping, nine inches of sand media overlying nine inches
of gravel media, two foot concrete dividers between beds, and an underdrain system to remove
percolating water. Land costs are excluded from the cost estimates.
Energy requirements are based on: a front-end loader to remove dried sludge from the beds and
prepare the bed for the next sludge application; cleaning and preparation time of 3 hours for a 4,000
square foot bed; diesel fuel consumption of 4 gallons per hour; and 20 cleanings/bed/year.
9.4 Costs for Regulatory Options
The following sections present the costs estimated for compliance with BPT, BCT, BAT, PSES,
NSPS, and PSNS effluent limitations guidelines and standards for the Subtitle D Non-Hazardous and
Subtitle C Hazardous subcategories. Costs for each of the regulatory options are presented below
for only the facilities in the 308 Questionnaire database, as well as, for all of the facilities in the
Landfills industry based on national estimates (see Chapter 3, Section 3.2.1 for an explanation of
national estimates). All costs estimates in this section are expressed in terms of 1992 dollars, unless
otherwise noted.
9.4.1 BPT Regulatory Costs
Preliminary cost effectiveness analyses were developed by EPA using interim costing rounds to select
proposed BPT regulatory options. The BPT costs for each subcategory are presented below.
9.4.1.1 Subtitle D Non-Hazardous Subcategorv BPT Costs
Once current discharge and untreated landfill wastewater pollutant concentrations were developed
for facilities in the Subtitle D Non-Hazardous subcategory, EPA evaluated two options; BPT Option
I and II.
BPT Option I: Equalization and activated sludge biological treatment with sludge dewatering. For
the facilities in the 308 Questionnaire database, Table 9-11 presents the total capital ($3,201,715) and
9-26
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annual O&M costs ($927,555) for this option, as well as, the total amortized annual cost for each
facility. Based on national estimates, BPT Option I for the Subtitle D Non-Hazardous subcategory
is estimated to have total annualized pre-tax and post-tax costs of $5.97 and $5.43 million (based on
1992 dollars), respectively.
BPT Option II: Equalization, activated sludge biological treatment, and multi-media filtration with
sludge dewatering. For the facilities in the 308 Questionnaire database, Table 9-12 presents the total
capital ($3,801,954) and annual O&M ($1,197,169) costs for this option, as well as, the total
amortized annual cost for each facility. Based on national estimates, BPT Option II for the Subtitle
D Non-Hazardous subcategory is estimated to have total annualized pre-tax and post-tax costs of
$7.73 and $6.85 million (based on 1992 dollars), respectively.
9.4.1.2
Subtitle C Hazardous Subcategorv BPT Costs
Once current discharge and untreated landfill wastewater pollutant concentrations were developed
for facilities in the Subtitle C Hazardous subcategory, EPA evaluated one BPT option; BPT Option
I.
BPT Option I: Equalization, chemical precipitation, and activated sludge biological treatment with
sludge dewatering. Since EPA has estimated that there are no direct discharge facilities in the Subtitle
C Hazardous subcategory database, there are no costs associated with this option.
9.4.2
BCT Regulatory Costs
Prehminary cost effectiveness analyses were developed by EPA-using interim costing rounds to select
proposed BCT regulatory options. The BCT costs for each subcategory are presented below.
9-27
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9.4.2.1 Subtitle D Non-Hazardous Subcategorv BCT Costs
Once current discharge and untreated landfill wastewater pollutant concentrations were developed
for facilities in the Subtitle D Non-Hazardous subcategory, EPA evaluated two options; BCT Option
I and II.
BCT Option I: Equalization and activated sludge biological treatment with sludge dewatering. This
option is equivalent to BPT Option I for the Non-Hazardous subcategory with costs previously
provided in Section 9.4.1.1 above.
BCT Option II: Equalization, activated sludge biological treatment, and multi-media filtration with
sludge dewatering. This option is equivalent to BPT Option II for the Non-Hazardous subcategory
with costs previously provided in Section 9.4.1.1 above.
9.4.2.2
Subtitle C Hazardous Subcategorv BCT Costs
Once current discharge and untreated landfill wastewater pollutant concentrations were developed
for facilities hi the Subtitle C Hazardous subcategory, EPA evaluated one option; BCT Option I.
BCT Option I: Equalization, chemical precipitation, and activated sludge biological treatment with
sludge dewatering. This option is equivalent to BPT Option I for the Subtitle C Hazardous
subcategory, and therefore, has no associated costs.
9.4.3 BAT Regulatory Costs
Preliminary cost effectiveness analyses were developed by EPA'using interim costing rounds to select
proposed BAT regulatory options. The BAT costs for each subcategory are presented below.
9.4.3.1 Subtitle D Non-Hazardous Subcategorv BAT Costs
EPA costed three BAT options for the Subtitle D Non-Hazardous subcategory; BAT Options I, II
and III.
9-28
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BAT Option I: Equalization and activated sludge biological treatment with sludge dewatering. This
option is equivalent to BPT Option I for the Non-Hazardous subcategory with costs previously
provided in Section 9.4.1.1 above.
BAT Option II: Equalization, activated sludge biological treatment, and multi-media filtration with
sludge dewatering. This option is equivalent to BPT Option II for the Non-Hazardous subcategory
with costs previously provided in Section 9.4.1.1 above.
BAT Option III: Equalization, activated sludge biological treatment, multi-media filtration, and
reverse osmosis with sludge dewatering. For facilities in the 308 Questionnaire database, Table 9-13
presents the total capital ($38,952,560) and annual O&M ($6,481,452) costs for this option, as well
as, the total amortized annual cost for each facility. Based on national estimates, BAT Option III for
the Subtitle D Non-Hazardous subcategory is estimated to have a total annualized post-tax cost of
$29.16 million (based on 1992 dollars). For comparison with other regulations for other industries,
the total annualized pre-tax cost for this option is estimated at $21.97 million (based on 1981 dollars). .
9.4.3.2
Subtitle C Hazardous Subcategory BAT Costs
Once current discharge and untreated landfill wastewater pollutant concentrations were developed
for faculties in the Subtitle C Hazardous subcategory, EPA evaluated one BAT option; BPT Option
I.
BAT Option I: Equalization, chemical precipitation, and activated sludge biological treatment with
sludge dewatering. This option is equivalent to BPT Option I for the Hazardous subcategory, and
therefore has no associated costs.
9.4.4
PSES Regulatory Costs
Preliminary cost effectiveness analyses were developed by EPA using interim costing rounds to select
proposed PSES regulatory options. The PSES costs for each subcategory are presented below.
9-29
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9.4.4.1
Subtitle D Non-Hazardous Subcategory PSES Costs
EPA estimates compliance costs for facilities in the Subtitle D Non-Hazardous subcategory for one
PSES option; PSES Option I.
PSES Option I: Equalization and activated sludge biological treatment with sludge dewatering. For
facilities in the 308 Questionnaire database, Table 9-14 presents the total capital ($11,764,213) and
annual O&M ($1,957,211) costs for this option, as well as, the total amortized annual cost for each
facility. Based on national estimates, the cost for this PSES option is estimated at $28.2 million
(based on 1992 dollars).
9.4.4.2 Subtitle C Hazardous Subcategorv PSES Costs
For the Subtitle C Hazardous subcategory, EPA evaluated one PSES option; PSES Option I.
PSES Option I: Equalization, chemical precipitation, and activated sludge biological treatment with
sludge dewatering. All of the landfills in the Hazardous subcategory which indirectly discharge their
wastewaters hi EPA's survey of the industry are expected to be in compliance with the baseline
treatment standards established for indirect dischargers. Therefore, EPA has projected that there will
be no costs associated with compliance for the proposed PSES regulation for this subcategory.
9.4.5 NSPS Regulatory Costs
Preliminary cost effectiveness analyses were developed by EPA using interim costing rounds to select
proposed NSPS regulatory options. The NSPS costs for each subcategory are presented below.
9.4.5.1
Subtitle D Non-Hazardous Subcategorv NSPS Costs
EPA is proposing NSPS for the Subtitle D Non-Hazardous subcategory to be equivalent to the
limitations proposed for BPT Option II for this subcategory, which also is the basis for BCT, BAT,
and PSES Option II.
9-30
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NSPS: Equalization, activated sludge biological treatment and multi-media filtration with sludge
dewatering. The total NSPS annual cost for the Non-Hazardous subcategory is $49,600 assuming
an average facility flow of 10,000 gpd.
9.4.5.2
Subtitle C Hazardous Subcategorv NSPS Costs
EPA is proposing NSPS for the Subtitle C Hazardous subcategory to be equivalent to the limitations
proposed for BPT Option I for this subcategory, which also is the basis for BCT, BAT, and PSES
Option I.
NSPS: Equalization, chemical precipitation, and activated sludge biological treatment with sludge
dewatering. The total NSPS annual cost for the Hazardous subcategory is $152,700 assuming an
average facility flow of 10,000 gpd.
9.4.6
PSNS Regulatory Costs
Preliminary cost effectiveness analyses were developed by EPA using interim costing rounds to select
proposed PSNS regulatory options. The PSNS costs for each subcategory are provided below.
9.4.6.1
Subtitle D Non-Hazardous Subcategorv PSNS Costs
Since EPA is not proposing PSNS standards for Subtitle D Non-Hazardous subcategory, there are
no costs associated with this requirement.
9.4.6.2
Subtitle C Hazardous Subcategory PSNS Costs
EPA is proposing PSNS for the Subtitle C Hazardous subcategory to be equivalent to the limitations
proposed for BPT Option I for this subcategory, which also is the basis for BCT, BAT, and PSES
Option I.
9-31
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PSNS: Equalization, chemical precipitation, and activated sludge biological treatment with sludge
dewatering. The total PSNS annual cost for the Hazardous subcategory is $141,400 assuming an
average facility flow of 5,600 gpd.
9-32
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