Treatment of microbial contaminants in potable water supplies : technologies and costs

Contents and Subject Index EXECUTIVE SUMMARY 1 Introduction 1 Definition of Technology Categories 2 Most Applicable Technologies 2 Other Applicable Technologies 2 Additional Technologies 2 Background 2 Waterborne Disease Outbreaks 2 Filtration in Community Systems 5 General 6 Effectiveness of Filtration for Removal of Microbial Contaminants 6 Discussion of Most Applicable Technologies 9 Conventional Treatment 9 Direct Filtration 9 Diatomaceous Earth Filtration 9 Slow-Sand Filtration ...........,................. 10 Package Plants 10 Disinfection in Community Systems. . . . . . . . 10 General 11 Most Applicable Technologies 11 Chlorination 12 Chlorine Dioxide 12 Chloramination 12 Ozonation 13 Small Water Systems 14 Treatment Technologies Applicable to Small Systems 14 Alternatives to Treatment 15 Cost Data 15 ix x Contents and Subject Index Groundwater Disinfection Costs. . . . . . . . . . . . . . . . . . . . 18 Surface Water Filtration Cost Calculations 18 Costs of Obtaining an Exception to the Surface Water Filtration Rule 19 Costs for Presently Filtering Systems to Improve Their Disinfection Facilities 19 Cost Range Information Regarding Land, Piping, and Finished Water Pumping 19 I. INTRODUCTION 24 Purpose of the Document. . . . . . . . . . . . . . . . . . . . . . . 24 Definition of Technology Categories 25 Most Applicable Technologies 26 Filtration 27 Disinfection 27 Other Applicable Technologies 27 Filtration 27 Disinfection 28 Additional Technologies 28 II. BACKGROUND 29 General 29 Waterborne Disease Outbreaks-1946 to 1980 29 Waterborne Disease Outbreaks-1981 to 1983 35 Problems in Removing Microbial Contamination from Water Supply Sources 39 False Sense of Security 40 Protected Watersheds 40 Turbidity Standard 41 Monitoring Microbial Contaminants 41 Coliforms as Indicator Organisms 41 Turbidity as an Indicator of Water Quality 44 Particle Counting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 46 Treatment for Control of Bacteria and Viruses 46 By-Products of Disinfection 49 Treatment for Control of Giardia and Removal of Turbidity 50 Case Histories 51 Argument for Multiple Barriers 52 Alternative Approaches to Microbial Contaminant Control . . . . 53 Quality Requirements 54 Surface Water Treatment Requirements 55 Conditions When Filtration May Not Be Necessary 55 III. FILTRATION IN COMMUNITY SYSTEMS 58 General 58 Effectiveness of Filtration for Removal of Microbial Contaminants 58 Discussion of Most Applicable Technologies 61 Conventional Treatment 61 Contents and Subject Index xi Process Description 61 Laboratory and Pilot Plant Studies 64 Case Histories 66 Montreal 66 Denver 67 Sacramento 67 Direct Filtration 67 Process Description 67 Laboratory and Pilot Plant Studies 71 Case Histories 74 Lake Oswego 74 Virginia 74 Erie County 74 Two Harbors 75 Portola 76 Diatomaceous Earth Filtration 76 Process Description 76 Laboratory and Pilot Plant Studies 79 Slow-Sand Filtration 80 Process Description 80 Laboratory and Pilot Plant Studies 82 Case Histories 83 Denver Water Board 83 Survey of 27 Plants 84 New York State 89 Mcindoe Falls 91 Package Plants 92 Process Description 92 Package Plant Performance 94 IV. DISINFECTION IN COMMUNITY SYSTEMS 98 General 98 Most Applicable Technologies 99 Chlorination 103 General 103 Performance 105 Laboratory Research and Pilot-Plant Studies 106 Plant-Scale Testing 118 Summary 120 Chlorine Dioxide 121 General 121 Performance 122 Laboratory Research and Pilot Studies 122 Summary 125 Chloramination 128 General 128 Performance 129 Case Histories 132 xii Contents and Subject Index Philadelphia Suburban Water Company (PSWC) 135 Fort Meade, Maryland 135 Summary 135 Ozonation 135 General 135 Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 Laboratory Research and Pilot Plant Studies 140 Plant-Scale Results 142 Summary 143 Other Applicable Technologies 143 Iodine 143 General 143 Performance 145 Laboratory Research 145 NoncommunitY Use 146 Bromine 147 Ultraviolet Radiation 147 Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Laboratory Research 149 Heat Treatment 151 Additional Technologies 151 Disinfection with Filtration. . 153 V. SMALL WATER SYSTEMS 154 General . . . . . . . . . . . . . . . . . . 154 CommunitY Systems 154 l\Joncommunity Systems 154 Water Requirements 154 Waterborne Disease Outbreaks 156 Treatment Facilities Used by Small Water Systems 157 Difficulties Specific to Small Systems 157 Treatment Technologies Applicable to Small Systems 158 Filtration Technologies 159 Package Plants 159 Slow-Sand Filters 159 Diatomaceous Earth Filters 160 Ultrafiltration 160 Cartridge Filters 161 Disinfection Technologies 163 Hypochlorination and Gaseous Chlorination 163 Iodination 164 Erosion Feed Chlorinators 164 Ultraviolet Radiation 165 Ozonation 166 Alternatives to Treatment 166 Wells 166 Purified Water Vending Machines 166 Contents and Subject Index xiii VI. COST DATA 168 Basis of Costs-General 168 Capital Costs 168 Operation and Maintenance Costs 169 Updating Costs to the Time of Construction 171 Basis of Costs-Process by Process. . . . . . . . . . . . . . . . . . . . . 172 Pumping 172 Package Raw Water Pumping 174 Raw Water Pumping 175 In-Plant Pumping 175 Backwash Pumping 176 Package High-Service Pumping 177 Finished Water Pumping 178 Unthickened Chemical Sludge Pumping 178 Thickened Chemical Sludge Pumping 179 Chemical Feed 179 Basic Chemical Feed 180 Liquid Alum Feed 181 Polymer Feed 182 Sodium HydrOXide Feed 183 Lime Feed 184 Sulfuric Acid Feed 185 Filtration Process Components 186 Rapid Mix 186 Flocculation 187 Rectangular Clarifiers 188 Tube Settling Modules 188 Gravity Filtration 189 Convert Rapid·Sand Filters to Mixed-Media Filters 190 Filter-to-Waste Facilities 190 Slow-Sand Filters 191 Pressure Filtration 192 Contact Basins for Direct Filtration 193 Hydraulic Surface Wash Systems 194 Washwater Surge Basins 194 Automatic Backwashing Filter 195 Clearwell Storage 196 Package Pressure Diatomite Filtration 196 Pressure Diatomite Filters 197 Package Ultrafiltration Plants 198 Package Conventional Complete Treatment 199 Disinfection Processes 200 Chlorine Storage and Feed Systems 200 Chlorine Dioxide Generation and Feed 202 Ozone Generation, Feed, and Contact Chambers 203 Ammonia Feed Facilities 204 Ultraviolet Light Disinfection 205 Solids Handling Processes 206 xiv Contents and Subject Index Sludge Holding Tanks 206 Sludge Dewatering Lagoons 206 Liquid Sludge Hauling 207 Gravity Sludge Thickeners 208 Filter Press 208 Dewatered Sludge Hauling 209 Administration, Laboratory and Maintenance Building 209 Alternatives to Treatment 210 Constructing a New Well 210 Conceptual Design 210 Operation and Maintenance Requirements 211 Bottled Water Vending Machines 211 Conceptual Design 211 Operation and Maintenance Requirements 212 Typical Treatment Costs for Surface Water 212 Filtration 213 Package Complete Treatment 213 Conventional Treatment 213 Conventional Treatment with Automatic Backwashing Filters 213 Direct Filtration 213 Diatomaceous Earth Filtration 214 Slow-Sand Filtration 214 Package Ultrafiltration 223 Disinfection 223 Chlorination 223 Ozone Disinfection 223 Chlorine Dioxide and Chloramination 223 Ultraviolet Light 223 Supplemental Process Costs for Surface Water Treatment 230 Additional Chemical Feed Facilities 230 Modifications to Rapid-Sand Filters 230 Adding Tube Settling Modules 230 Direct Filtration Modifications 239 Additional Filtration Facilities 239 Finished Water Pumping 239 Additional Instrumentation 239 Alternatives to Treatment 248 Cost Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 249 REFERENCES 255 APPENDIX A: GROUNDWATER DISINFECTION COSTS 277 APPENDIX B: SURFACE WATER FILTRATION COST CALCULATIONS 284 Contents and Subject Index xv APPENDIX C: COSTS OF OBTAINING AN EXCEPTION TO THE SURFACE WATER FILTRATION RULE 298 APPENDIX D: COSTS FOR PRESENTLY FI LTERI NG SYSTEMS TO IMPROVE THEIR DISINFECTION FACILITIES 314 APPENDIX E: COST RANGE INFORMATION REGARDING LAND. PIPING. AND FINISHED WATER PUMPING 328 ABBREVIATIONS AND SYMBOLS 332 METRIC CONVERSIONS 335