Upgrading existing or designing new drinking water treatment facilities

1. INTRODUCTION 3 2. SELECTING AND EVALUATING TREATMENT PROCESSES 4 2.1 Overview of Federal Drinking Water Regulations 4 2.2 Selecting Treatment Technologies 6 2.3 Overview of Available Treatment Alternatives 8 2.3.1 Filtration ~ 8 2.3.2 Disinfection 10 2.3.3 Organic Contaminant Removal. 12 2.3.4 Inorganic Contaminant Removal and Control 13 2.3.4.1 Corrosion Controls 13 2.3.4.2 Inorganic Contaminant Removal 13 2.4 Final Process Selection and Design 15 3. PREFILTRATION TREATMENT ELEMENTS 18 3.1 Modifying Chemical Feed 19 3.1.1 Chemical Type 19 3.1.2 Chemical Dosage Management 20 3.1.3 Chemical Application Methods and Considerations 22 3.2 Modifying or Adding Rapid Coagulant Mixing 23 3.3 Improving Flocculation 26 3.3.1 Improving Mixing 26 3.3.2 Improving Flocculator Inlet and Outlet Conditions 27 3.3.3 Improving Basin Circulation with Baffles 28 3.4 Improving Sedimentation 28 3.4.1 Horizontal Flow Sedimentation Basins 30 3.4.2 Upflow Solids Contact Clarifiers 31 4. FI LTRATION TECHNOLOGIES 34 4.1 Modifying Filtration Systems 34 4.1.1 General Effectiveness of Filtration Systems 35 4.1.2 Filtration System Improvements 35 vii viii Contents and Subject Index 4.1.3 System Design Checklist 38 4.2 Direct Filtration 38 4.2.1 Process Description 38 4.2.2 System Performance 39 4.3 Slow Sand Filtration 39 4.3.1 System Design Considerations 40 4.3.2 Operation and Maintenance 40 4.3.3 System Performance 42 4.3.4 System Costs 42 4.4 Package Plant Filtration 42 4.4.1 Selecting a Package Plant System 43 4.4.2 System Description and Design Considerations 43 4.4.3 Operation and Maintenance 44 4.4.4 System Performance 45 4.4.5 System Costs 45 4.5 Diatomaceous Earth Filtration 45 4.5.1 System Design 47 4.5.2 Operation and Maintenance 47 4.5.3 System Performance 48 4.5.4 System Costs 48 4.6 Other Filtration Systems 49 4.6.1 Membrane Fi Itration 49 4.6.2 Cartridge Filtration 52 4.7 Selecting the Appropriate Filtration Treatment System 53 4.7.1 Steps in an Evaluation 53 4.7.2 Need for Pilot Studies 54 4.7.3 Flocculation and Sedimentation Studies 54 4.7.4 Filtration Studies 54 5. DISINFECTION AND DISINFECTION BY-PRODUCTS 57 5.1 The Objectives of Disinfection 57 5.1.1 CT Values 58 5.2 Disinfection By.Products 59 5.2.1 The Chemistry of Oxidation 60 5.2.2 The Presence of Disinfection By-Products in Drinking Water 61 5.2.3 Strategies for Controll ing Disinfection By-Products 61 5.3 Comparing Disinfectants 63 5.3.1 Chlorine 63 5.3.2 Chlorine Dioxide 63 5.3.3 Monochloramine 63 5.3.4 Ozone 64 5.3.5 Ultraviolet Radiation 65 5.3.6 Advanced Oxidation Processes 65 5.4 Primary Disinfection Technologies 65 5.4.1 Chlorine 66 5.4.1.1 Process Description , '" " , .66 5.4.1.2 Disinfection with Chlorine Gas 69 5.4.1.3 Disinfection with Sodium Hypochlorite Solution 71 5.4.1.4 Disinfection with Solid Calcium Hypochlorite 72 5.4.2 Ozone 72 5.4.2.1 Process Description 72 5.4.2.2 System Design Considerations 73 5.4.2.3 Costs of Ozonation Systems 79 5.4.3 Chlorine Dioxide 81 Contents and Subject Index ix 5.4.3.1 Process Descri ption 82 5.4.3.2 Establishing a Chlorine Dioxide Residual. 83 5.4.3.3 Chlorine Dioxide System Design Considerations 85 5.4.3.4 Costs of Chlorine Dioxide Disinfection 86 5.4.4 Ultraviolet Radiation 87 5.4.4.1 Process Description 88 5.4.4.2 UV Disinfection System Design Considerations 90 5.4.4.3 UV System Operating and Maintenance Considerations 91 5.4.4.4 Costs of UV Radiation Systems 92 5.5 Secondary Disinfectants 92 5.5.1 Chloramination 92 5.5.1.1 Process Description , , , , .. , 93 5.5.1.2 Establishing a Chloramine Residual 93 5.5.1.3 Chloramination System Design Considerations 93 5.5.1.4 Costs for Chloramination 93 6. TREATMENT OF ORGANIC CONTAMINANTS 96 6.1 Pretreatment for Natural Organic Contaminant Removal. 96 6.1.1 Coagulant Pretreatment 98 6.1.2 Oxidation Pretreatment 99 6.2 Granular Activated Carbon 99 6.2.1 Process Design Considerations 100 6.2.2 Tests for Deriving Carbon Usage and Other Design Criteria 103 6.2.3 Least Cost Design Criteria 103 6.2.4 Facility Design Criteria 104 6.2.5 Operation and Maintenance 104 6.2.6 System Performance 105 6.2.7 System Costs 105 6.3 Packed Column Aeration 108 6.3.1 System Design Considerations 111 6.3.2 Pilot Testing PCA 111 6.3.3 VOC Emission Control 112 6.3.4 Operation and Maintenance 114 6.3.5 System Performance 114 6.3.6 System Costs 114 6.4 Powdered Activated Carbon Plus Conventional Treatment 117 6.4.1 PAC Application Techniques 117 6.4.2 System Design Considerations 118 6.4.3 System Performance , 119 6.5 Diffused Aeration 119 6.5.1 System Design Considerations 120 6.5.2 System Performance 120 6.6 Multiple Tray Aeration 120 6.6.1 System Design 120 6.6.2 System Performance 120 6.7 Emerging Applications of Treatment Technologies for Organic Contaminants 120 6.7.1 Oxidation Including Ozone 121 6.7.2 Reverse Osmosis .. , 123 6.7.3 Mechanical Aeration 123 6.7.4 Catenary Grid 123 6.7.5 Higee Aeration 123 6.7.6 Resins 124 7. TREATMENTS FOR INORGANIC CONTAMINANTS 129 7.1 Techniques for Controlling Corrosion 129 x Contents and Subject Index 7.1.1 The Problem of Corrosion 130 7.1.2 Diagnosing and Evaluating the Problem 131 7.1.2.1 Consumer Complaints , " 131 7.1.2.2 Corrosion Indices 131 7.1.2.3 Sampling and Chemical Analysis 132 7.1.2.4 Scale or Pipe Surface Examination 132 7.1.2.5 Rate Measurements 133 7.1 .3 Corrosion Controls 133 7.1.3.1 Distribution and Plumbing System Design Considerations 134 7.1.3.2 Water Quality Modifications 134 7.1.3.3 Corrosion Inhibitors 136 7.1.3.4 Cathodic Protection 137 7.1.3.5 Coatings and Linings 137 7.2 Treatment Technologies for Controlling Inorganic Contaminants, Including Radionuclides 137 7.2.1 Removing Radionuclides in Drinking Water 139 7.2.1.1 Costs , 139 7.2.2 Conventional Treatment: Coagulation and Lime Softening 139 7.2.2.1 Coagulation 140 7.2.2.2 Lime Softening 142 7.2.3 Reverse Osmosis 142 7.2.3.1 Design Considerations 143 7.2.3.2 System Performance 146 7.2.3.3 System Costs 146 7.2.4 Ion Exchange 146 7.2.4.1 System Performance 146 7.2.5 Activated Alumina 147 7.2.5.1 System Performance 149 8. CURRENT AND EMERGING RESEARCH 150 8.1 Current Research on Disinfection By·Products 150 8.1.1 Identifying and Controll ing Chlorination By-Products 151 8.1.2 Identifying Ozone By·Products 151 8.2 Treatment of Organic and Inorganic Contaminants 151 8.2.1 Granular Activated Carbon Systems 152 8.2.1.1 Establishing Carbon Usage Rates 152 8.2.1.2 Field Tests of Granular Activated Carbon Systems 153 8.2.2 Ozone Oxidation Systems 154 8.2.3 Ultraviolet Treatment 154 8.2.4 Reverse Osmosis 154 8.2.5 Ultrafiltration 154 8.2.6 Packed Tower Aeration 154 8.2.7 Conventional Treatment 155 8.2.8 Ion Exchange 155 8.2.9 Technologies for Removing Radionuclides 155 8.2.10 Secondary Sources of Pollution , 156 8.2.11 Small Systems Technologies 156 8.3 Mandatory Disinfection 156 8.3.1 Treatment/Distribution Microbiology 156 8.3.2 Bacterial Detection/Monitoring 157 8.4 Prohibition of Lead Materials 157 8.5 Systems and Cost Modeling Studies 157 8.6 Future Directions 158 Contents and Subject Index xi 9. REFERENCES , 159 APPENDIX A-EXPERIENCE MODIFYING EXISTING FILTRATION SYSTEMS 165 A.1 Upgrading Existing Treatment Facilities 165 A.1.1 Horizontal Flow Basin Example 165 A.1.2 Upflow Solids Contact Clarifier Example 166 A.1.3 Sacramento, California (Sequeira et ai, 1983) 166 A.1.4 Erie County, New York (Westerhoff, 1971) ., 166 A.1.5 Corvallis, Oregon (Collins and Shieh, 1971) 167 A.1.6 Novato, California (Culp, 1976) 168 A.2 Slow Sand Filter Systems 169 A.2.1 Idaho State (Tanner, 1988) 169 A.2.2 New York State (Letterman and Cullen, 1985) 169 A.2.3 Mcindoe Falls, Vermont (Pyper, 1985) 170 A.2.4 Village of 100 Mile House, British Columbia, Canada (Bryck et ai, 1987) 171 A.3 Package Plants 171 A.3.1 Conventional Package Plants (Morand and Matthew, 1983) 171 A.3.2 Adsorption Clarifier Package Plants 172 A.4 Diatomaceous Earth Filters 176 AA.1 Colorado State University Study (Lange et ai, 1984) 176 AA.2 Mcindoe Falls, Vermont (Pyper, 1985) 176 A.5 Selecting a Filtration System 176 A.5.1 Lake County, California (Conley and Hansen, 1987) 176 APPENDIX 8-CASE HISTORIES OF EMERGING DISINFECTION TECHNOLOGIES 180 8.1 Ozone Case Histories 180 B.1.1 Primary Disinfection with Ozone: North Andover, Massachusetts 180 B.1.2 Preozonation for THM Control: Kennewick, Washington (Cryer, 1986) 181 8.2 UV Radiation Case Histories 183 B.2.1 Ultraviolet Radiation for Primary Disinfection: Fort Benton, Montana 183 8.3 Chlorine Dioxide Case Histories 183 B.3.1 Predisinfection for THM Control: Evansville, Indiana (Lykins and Griese, 1986) 183 B.3.2 Primary and Secondary Disinfection with Chlorine Dioxide: Hamilton, Ohio (Augenstein, 1974; Miller et ai, 1978; U.S. EPA, 1983) 184 8.3.3 Preoxidation with Chlorine Dioxide, Postchlorination with Chlorine Dioxide and Chloramine: Galveston, Texas (Myers et ai, 1986) 186 8.4 Chloramine Case Histories 187 BA.1 Prechlorination, Postchloramination: Bloomington, Indiana (Singer, 1986) 187 BA.2 Prechlorine Dioxide, Prechlorination, and Postchloramination: Phi ladel ph ia, Pennsylvania (McKeon et ai, 1986) 187 APPENDIX C-EXPERIENCE WITH TREATMENT TECHNOLOGIES FOR ORGANIC CONTAMINANTS 190 C.1 Experience with Granular Activated Carbon 190 C.1.1 GAC for VOC Removal: Washington, New Jersey (Chrobak et ai, 1985) 190 C.1.2 GAC for Contaminant Control: Cincinnati, Ohio (DeMarco, 1983) (Westerhoff and Miller, 1985) 190 C.1.3 EPA Health Advisory Example 191 C.2 Experience with PTA: Scottsdale, Arizona (Cline et ai, 1985) 191 C.3 Experience with PAC 192 APPENDIX D-EXPERIENCE WITH TREATMENT TECHNOLOGIES FOR INORGANIC CONTAMINANTS 197 D.1 Corrosion Control 197 xii Contents and Subject Index 0.1.1 Controlling Lead: Seattle, Washington 197 0.1.2 Control Iing Lead with pH Adjustment: Boston, Massachusetts 197 D.2 Coagulation to Control Barium: Illinois 198 D.3 Reverse Osmosis: Sarasota, Florida 198 D.4 Ion Exchange: McFarland, California 199 0.5 Activated Alumina: Gila Bend, Arizona 200 APPENDIX E-SUMMARY OF CORROSION INDICES 203 PART II WATER TREATMENT TECHNOLOGIES FOR SMALL COMMUNITIES INTRODUCTION 207 1. DRINKING WATER TREATMENT: AN OVERVIEW 208 Why Do We Need Drinking Water Treatment? 208 How Is Drinking Water Treated? 210 Fi Itration 211 Disinfection 211 Treatment of Organic Contaminants 211 Treatment of Inorganic Contaminants 211 2. NEW AND PROPOSED DRINKING WATER TREATMENT REGULATIONS: AN OVERVIEW 213 Compliance Schedules 214 Maximum Contaminant Levels 214 MCLs for Volatile Organic Compounds 215 MCLs for Inorganic and Synthetic Organic Compounds 215 MCLs for Microbiological Contaminants 215 MCLs for Radionuclide Contaminants 215 MCLs for Disinfectants and Disinfection By-Products 215 Monitoring , , 217 Volatile Organic Chemicals 217 Fluoride 217 Radionuclides 217 Microbiological Contaminants 217 Laboratory Analysis and Sampling Requirements 220 Surface Water Treatment Requirements 221 3. SOLUTIONS TO DRINKING WATER TREATMENT PROBLEMS: AN OVERVIEW 223 Questions to Consider in Choosing Treatment Technologies 223 What Are the Requirements for Drinking Water Suppl ied by the System? 225 Are Nontreatment Alternatives Available? 225 What Are the Characteristics of the Raw Water? 225 What Is the Configuration of the Existing System? 226 What Are the Costs of the Treatment Options? 227 What Are the Treatment Technology's Operating Requirements? 227 How Compatible Are the Processes Used? 227 What Waste Management Issues Are Involved? 227 What Are the Future Needs of the Service Area? 227 Special Issues for Small Systems 227 Financial/Capital Improvement 227 Multicommunity Cooperative Arrangements (Regionalizationl 228 Operator Capabilities 229 Contents and Subject Index xiii Selecting a Consulting Engineer/Equipment Vendor 232 Using a Point-of-Use/Point-of·Entry (POU/POE) System 232 4. FI LTRATION TECHNOLOGIES FOR SMALL SYSTEMS 233 Processes Preceding Filtration 233 Choosing a Filtration Technology 234 Slow Sand Filtration 234 Diatomaceous Earth Filtration 237 Package Plants 238 Membrane Filtration (Ultrafiltration) 238 Cartridge Filtration 239 Innovative Filtration Technologies 240 5. DISINFECTION 241 Chlorination 241 Disinfection Terminology 241 Factors Affecting Chlorination Efficiency 241 Chlorination Chemicals 242 Disinfection with Sodium Hypochlorite Solution 242 Disinfection with Solid Calcium Hypochlorite 243 Hypochlorination Equipment 244 Disinfection with Chlorine Gas 244 Chlorination Monitoring 245 Ozonation 245 Monitoring the Ozonation System Operation 247 Ultraviolet Radiation (UV) 247 Obtaining Effective Disinfection: CT Values 248 Disinfection By-Products and Strategies for Their Control 248 6. TREATING ORGANIC CONTAMINANTS IN DRINKING WATER 250 Granular Activated Carbon 250 Aeration 252 Packed Column Aeration 253 Diffused Aeration 253 Multiple Tray Aeration 254 Emerging Technologies for Organics Removal 254 Mechanical Aeration 254 Catenary Grid. . . 254 Higee Aeration 254 7. CONTROL AND REMOVAL OF INORGANIC CONTAMINANTS 256 Corrosion 256 Controlling Lead Levels in Drinking Water 256 Techniques for Controlling Corrosion 257 Treatment Technologies for Removing Inorganic Contaminants 258 Coagulation/Filtration 260 Reverse Osmosis and Electrodialysis 261 Ion Exchange 261 Activated Alumina 262 Technologies for Radon Removal: Aeration and Granular Activated Carbon 263 8. RESOURCES . Safe Drinking Water Hotline ... ........................... 264 . 264 xiv Contents and Subject Index U.S. Environmental Protection Agency Regional Offices 264 State Drinking Water Agencies 264 Organizations Assisting Small Systems 264 American Water Works Association (AWWAl Small Systems Program 264 National Rural Water Association (NRWA) 264 Rural Community Assistance Program (RCAP) 264 Farmers Home Administration (FmHAl 264 Publications 264 General 264 Sampling 270 Filtration 270 Disinfection 270 Corrosion Control 270 Radionuclide Removal 270 Well head Protection 271 Costs/Financial Management 271 Consultants 271 The Federal Register 271 APPENDIX A-HOW TO TAKE BACTERIOLOGICAL SAMPLES 272 APPENDIX B-CHECKLlST: SOME FACTORS AFFECTING WATER TREATMENT SYSTEM PERFORMANCE 273 Administration 273 Maintenance 273 Design 273 Operation 274 APPENDIX C-SELECTING A CONSULTING ENGINEER 275 APPENDIX D-CHLORINE RESIDUAL MONITORING 278 Demonstration of Maintaining a Residual. 278 Maintaining a Residual Entering the System 278 Maintaining a Residual Within the System 279 APPENDIX E-CT VALUES 280 APPENDIX F-SAMPLE OF CT CALCULATION FOR ACHIEVING 1-LOG GIARDIA, 2-LOG VIRUS INACTIVATION WITH CHLORINE DISINFECTION 282 PART III THE COMPOSITE CORRECTION PROGRAM FOR OPTIMIZING WATER TREATMENT PLANT PERFORMANCE 1. INTRODUCTION 287 Purpose 287 Background 287 Content. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 287 2. THE COMPOSITE CORRECTION PROGRAM APPROACH 288 The Comprehensive Performance Evaluation 288 Design Components 288 Operation and Maintenance 288 Administration 289 Contents and Subject Index xv Evaluating the Factors that Limit Performance 289 Reporting 289 The Composite Correction Program 291 Implementing the Composite Correction Program 291 Maintaining Long- Term Involvement 291 3. RESULTS OF CASE STUDIES 293 CPE Findings 293 CCP Findings 296 Overall Factors Limiting Performance 296 4. CASE STUDIES 298 Plant 1 298 Plant 2 304 Plant 3 312 Plant 4 317 Plant 5 323 Plant 6 331 Plant 7 336 Plant 8 342 Plant 9 350 Plant 10 356 Plant 11 364 Plant 12 370 Plant 13 : 378