Theory and practice of water and wastewater treatment

Acknowledgments XXIPreface XXIIIAbbreviations and Acronyms Used in the Text XXVAbout the Companion Website XXXIIISection I: Chemistry 11 Basic Chemistry 31.1 Definitions 31.2 The Expression of Concentration 41.3 Ions and Molecules in Water 51.3.1 Oxidation Number 51.4 Balancing Reactions 91.5 Oxidation-Reduction Reactions 101.6 Equilibrium 121.7 Conductivity and Ionic Strength 131.7.1 Conductance 141.7.2 Ionic Strength 141.8 Chemical Kinetics 151.8.1 Other Formulations 16Consecutive or Series 16Parallel 17Retardant 17Autocatalytic 17Catalysis 181.8.2 The Effect of Temperature on Rate of Reaction 191.9 Gas Laws 191.10 Gas Solubility: Henry\'s Law 201.11 Solubility Product 231.12 Complexes 251.13 Nuclear Chemistry 271.13.1 Radioactivity Units 27Questions and Problems 30References 332 The Thermodynamic Basis for Equilibrium 352.1 Thermodynamic Relations 352.1.1 Free Energy 35Expression of Concentration in Equilibrium Expressions 392.1.2 Enthalpy and Temperature Effects on the Equilibrium Constant 422.2 Redox Potentials 432.2.1 Cell or Couple Potential 462.2.2 Oxidation-Reduction Potential and System Potential 482.3 Corrosion 492.3.1 Microbial Corrosion 512.3.2 Corrosion Prevention from External Environmental Factors 52 Galvanic Cathodic Protection 52Electrolytic (or Impressed Current) Cathodic Protection 53Questions and Problems 53References 553 Acid-Base Chemistry 573.1 pH 573.2 Acids and Bases 583.2.1 Conjugate Acids and Bases 613.3 Equivalents and Normality 613.4 Solution of Multiequilibria Systems 623.5 Buffers 633.5.1 Dilution of a Buffered Solution 653.5.2 The Most Effective pH for a Buffer 653.6 Acid-Base Titrations 663.6.1 Titration of Strong Acids and Bases 663.6.2 Titration of Weak Acids and Bases 683.6.3 Indicating the Endpoint of an Acid-Base Titration 713.7 Natural Buffering of Waters from Carbon Dioxide and Related Compounds 733.7.1 Acidity and Alkalinity 74Questions and Problems 76References 784 Organic and Biochemistry 814.1 Carbon 814.2 Properties of Organic Compounds 814.3 Functional Groups 824.4 Types of Organic Compounds 834.4.1 Aliphatic Compounds 83Aldehydes and Ketones 83Alcohols, Esters, and Ethers 834.4.2 Nitrogen-containing Compounds 834.5 Aromatic Compounds 844.5.1 Compounds of Sulfur 854.6 Naturally Occurring Organic Compounds 854.6.1 Carbohydrates 854.6.2 Proteins 864.6.3 Fats and Oils 864.7 Biochemistry 864.8 Glycolysis 874.9 The Tricarboxylic Acid Cycle 884.10 Enzyme Kinetics 89Questions and Problems 91References 935 Analyses and Constituents in Water 955.1 Titration 955.1.1 Complex and Precipitate Formation Titrations 955.1.2 Redox Titrations and Potentiometric Analyses 965.1.3 Indicators for Potentiometric Analysis 985.2 Colorimetric Analyses 995.2.1 The Beer-Lambert Laws for Light Transmittance 995.3 Physical Analyses 995.3.1 Solids 995.3.2 Turbidity and Color 1015.4 Determination of Organic Matter 1025.4.1 Chemical Oxygen Demand 103General Reaction for COD 104Interferences with the COD Test 1055.4.2 Biochemical Oxygen Demand 105Effects of Temperature on BOD Exertion 108Carbonaceous and Nitrogenous BOD 109Laboratory Methods for Determining BOD 110Limitations of the BOD Test for Biological Wastewater Treatment Process Design 110Analysis of a BOD Progression 1115.4.3 Total Organic Carbon 113Questions and Problems 113References 118Section II: Microorganisms in Water and Water Quality 1196 Microbiology 1216.1 Groups of Microorganisms and the Phylogenetic Tree 1216.2 Bacteria and Archaea 1216.2.1 Classification of Bacteria 124Taxonomy 124Metabolic Requirements 125Oxygen Requirements 125Temperature 126Salt and Sugar Concentrations 127pH 1276.3 Eukaryotes 1276.3.1 Algae 1286.3.2 Fungi 1296.3.3 Protists 1296.4 Other Microorganisms 1306.4.1 Viruses and Phages 1306.4.2 Rotifers 1316.4.3 Worms 1316.5 Determining the Growth of Microorganisms 1326.5.1 Growth of Pure Cultures 1326.5.2 Growth of Mixed Cultures 1356.5.3 Viability and Mass in Growing Cultures 1366.5.4 Enumeration of Microorganisms 136Plate Counts 136Practical Considerations in Determining Mean Values 1406.5.5 Microbial Genomics and Molecular Microbiology Tools 141Phylogenetic Microbial Community Composition Analysis 141Functional Analysis 142Questions and Problems 143References 1457 Water, Wastes, and Disease 1477.1 Agents of Disease 1477.1.1 Bacterial Pathogens 1477.1.2 Viral Pathogens 1497.1.3 Protozoan Pathogens 1507.1.4 Helminths 1507.1.5 Insect and Animal Vectors of Disease 1537.2 Indicator, Test, and Model Microorganisms 1537.3 Indicators of Fecal Contamination 1557.4 Indicator Microorganisms 1567.4.1 Coliforms: Total, Thermotolerant, and E. coli 1567.4.2 Enterococci 1577.5 Surrogates 1577.6 Survival of Microorganisms in the Aquatic Environment 1597.7 Minimum Infective Dose 162Questions and Problems 163References 1648 Water Constituents and Quality Standards 1678.1 Toxicity of Elements and Compounds 1678.2 Contaminants in Water 1708.2.1 Emerging Contaminants 1718.2.2 Common Contaminants 173Aluminum 173Nitrate 173Fluoride 173Detergents 1748.2.3 Carcinogens 1748.2.4 Radioactive Constituents 1758.3 Taste and Odor 1768.4 Bases for Standards 1788.4.1 Risk Assessment for Microbial Infection 1798.4.2 Determination of Carcinogenicity 1808.4.3 Toxicity Determination 1828.4.4 Environmental Water Quality Standards 1848.5 Standards for Drinking Water 1848.5.1 International Drinking Water Standards 1858.5.2 US Safe Drinking Water Act 1858.5.3 Canadian Water Quality Guidelines 1868.6 Comparison of Drinking Water Standards 1878.6.1 Microbiological Parameters 187WHO Guidelines for Microbiological Quality 187United States Standards for Microbiological Quality 187Canadian Guidelines for Microbiological Quality 1888.6.2 Chemical and Physical Qualities 1888.6.3 Aesthetic Quality 1888.6.4 Radiological Constituents 1888.6.5 Other Water Standards 1928.7 Water Consumption 1928.8 Canadian Federal Wastewater Quality Guidelines 1958.9 Wastewater Characteristics 195Greywater 1968.10 Wastewater Production 197Questions and Problems 198References 200Section III: Water and Wastewater Treatment 2059 Water and Wastewater Treatment Operations 2079.1 Water Treatment Operations 207Microbial Contaminants 212Reservoirs 2139.1.1 Home Water Treatment Units 2169.2 Wastewater Treatment Unit Operations 2169.3 Hydraulic Design of Water and Wastewater Treatment Plants 225Flow in Pressurized Pipes 225Flow in Open Channels 226Other Losses 227Questions and Problems 230References 23210 Mass Balances and Hydraulic Flow Regimes 23510.1 Setup of Mass Balances 23510.1.1 Mixing Characteristics of Basins 23610.1.2 Mass Balances for PF Reactors 237Method I 238Method II 239Method III 23910.1.3 Mass Balances and Reaction for CM Basins 24210.1.4 Batch Processes 24410.2 Flow Analysis of CM and PF Reactors 24510.2.1 Tracer Analysis of Complete Mixed Reactors 24510.2.2 Tracer Analysis of Plug Flow 24710.2.3 Complete Mixed Reactors in Series 24710.2.4 Other Flow Irregularities: Dead Volume and Short-circuiting 24810.2.5 Typical Flow Characteristics of Basins 24910.2.6 Measurement of Dispersion 25010.3 Detention Time in Vessels 25010.3.1 Average Detention Time 25110.3.2 The Effects of Flow Recycle on Detention Time 25110.3.3 The Effects of Recycle on Mixing 25310.4 Flow and Quality Equalization 25310.5 System Material Balances 256Questions and Problems 266References 271Section IV: Physical-Chemical Treatment Processes 27311 Screening and Sedimentation 27511.1 Screens and Bar Racks 27511.1.1 Screens for Water Treatment Plants 27611.1.2 Screens at Wastewater Treatment Plants 27711.1.3 Microstrainers 27711.2 Sedimentation 27811.2.1 Particle Settling Velocity 27911.3 Grit Chambers 28111.3.1 Horizontal Flow Grit Chambers 282Channel with Varying Cross Section 283Design Notes for a Parabolic Grit Chamber 28411.3.2 Aerated Grit Chambers 29011.3.3 Square Tank Degritter 29211.3.4 Vortex Grit Removal Devices 293Grit Washing 29411.4 Type I Sedimentation 29411.4.1 Theory 29411.5 Type II Sedimentation 29711.5.1 Laboratory Determination of Settling Velocity Distribution 29811.5.2 Type II Sedimentation Data Analysis 29811.5.3 Alternative Method for Calculating Total Removal 30211.5.4 Sizing the Basin 30311.6 Tube and Lamella Clarifiers 30311.7 Weir-Launder Design 30911.8 Clarifier Design for Water and Primary Wastewater Treatment 31311.8.1 Design Ranges for Typical Clarifiers for Water and Wastewater Treatment 31311.8.2 Chemically Enhanced Primary Treatment 31511.8.3 Depth in Sedimentation Basins 31811.9 Inlet Hydraulics for Sedimentation Basins 31911.9.1 Flow Distributions 31911.9.2 Inlet Baffling 322Questions and Problems 323References 32812 Mass Transfer and Aeration 33112.1 Fick\'s Law 33112.2 Gas Transfer 33212.2.1 Calculating the Mass Transfer Coefficient 33512.2.2 The Effects of pH on Mass Transfer 33612.3 Aeration in Water and Wastewater Treatment 33612.3.1 Hazards Associated with Oxygen, Carbon monoxide, and Hydrogen sulfide 33812.4 Design of Aeration Systems 33912.4.1 Gravity Aerators 33912.4.2 Spray Aerators 34112.4.3 Diffused Aerators 344Questions and Problems 346References 34813 Coagulation and Flocculation 35113.1 Coagulation 351Recovery of Alum and Iron Coagulants 35513.2 Mixing and Power Dissipation 35613.3 Mixers 35813.3.1 Mechanical Mixers 35913.3.2 Pneumatic Mixers 36213.3.3 Hydraulic Mixers 363Venturi Sections and Hydraulic Jumps 36313.4 Flocculators 36813.4.1 Paddle Flocculators 36913.4.2 Vertical-Shaft Turbine Flocculators 37513.4.3 Pipes 37613.4.4 Baffled Channels 37613.4.5 Upflow Solids Contact Clarifier 37713.4.6 Alabama Flocculator 37713.4.7 Spiral Flow Tanks 37813.4.8 Pebble Bed Flocculators 37913.4.9 Ballasted Flocculation 380Questions and Problems 382References 38414 Filtration 38714.1 Slow Sand Filters and Rapid Filters 38814.2 Filtering Materials 38914.2.1 Grain Size and Distribution 38914.3 Headloss in Filters 39414.3.1 Grain Size Distribution and Headloss 39714.4 Backwashing Filters 39814.4.1 Total Head Requirements for Backwashing 400Losses in the Expanded Media 40014.4.2 Backwash Velocity 401Method 1 401Method 2 402Headloss and Expansion in a Stratified Bed 40514.5 Support Media and Underdrains in Rapid Filters 409Other Design Features of Filters 411Auxiliary Wash and Air Scour Systems 41114.6 Filter Beds for Water and Wastewater Treatment 41214.7 Air Binding of Filters 41514.8 Rapid Filtration Alternatives 41714.8.1 Single-medium and Multimedia Filters 41714.8.2 Constant- and Declining-rate Filtration 41714.8.3 Direct Filtration 41814.9 Pressure Filters 41914.10 Slow Sand Filters 41914.10.1 Slow Sand Filters for Tertiary Wastewater Treatment 42114.11 Biological Filtration for Water Treatment 421Questions and Problems 424References 42715 Physical-Chemical Treatment for Dissolved Constituents 43115.1 Water Softening 43115.2 Lime-Soda Softening 43315.2.1 Treatment Methods for Lime-Soda Hardness Removal 43415.2.2 Bar Graphs 439Lime Recovery and Sludge Reduction 44115.3 Corrosion Prevention in Water Supply Systems 44115.3.1 The Langelier Index Misconception 44315.4 Iron and Manganese Removal 44715.4.1 Greensand 44815.4.2 Aeration 44915.4.3 Sequestering Iron and Manganese 44915.4.4 Biological Removal of Iron and Manganese 44915.5 Phosphorus Removal from Wastewater by Chemical Precipitation 45015.5.1 Removal of Phosphorus by Chemically Reactive Species 45215.6 Removal of Arsenic and Metals 45315.6.1 Metals Removal 45315.6.2 Arsenic Removal 45415.7 Advanced Oxidation Processes 45515.8 Ion Exchange 45615.8.1 Activated Alumina 45715.8.2 Ammonia and Nitrate Removal by Ion Exchange 45815.9 Fluoridation and Defluoridation 45815.10 Membrane Processes 46015.10.1 Assessment of Water Suitability for Membrane Treatment 46615.10.2 Concentrate Disposal 46815.10.3 Membranes for Water Treatment 468Microfiltration and Ultrafiltration Systems 468Nanofiltration and Reverse Osmosis Treatment 469Electrodialysis 47215.11 Activated Carbon Adsorption 47215.11.1 Activated Carbon - Preparation and Characteristics 47315.11.2 Adsorption Isotherms 47415.11.3 Granular Activated Carbon Adsorbers 47715.12 Design of Fixed-bed Adsorbers 47815.12.1 Rate Formulation for Adsorption 47915.12.2 Theory of Fixed-bed Adsorber Systems 480The Capacity Utilized in the Adsorption Zone 481Competitive Adsorption 49015.12.3 Bed-depth Service Time Method 49015.12.4 Rapid Small-Scale Column Tests 49415.12.5 Granular Activated Carbon Reactors in Series 49815.12.6 Design of a Suspended Media PAC or GAC Continuous Flow Reactor 498Questions and Problems 499References 50316 Disinfection 50916.1 Kinetics of Disinfection 51016.2 Chlorination 51216.2.1 Chemistry of Chlorine 51216.2.2 Measurement of Free and Residual Chlorine 51616.2.3 Chlorine Decay 51716.2.4 Drinking Water Disinfection by Chlorine 51816.2.5 Wastewater Disinfection by Chlorine 51916.2.6 Design of Contacting Systems for Chlorine 52116.2.7 Disinfection as the Sole Treatment of Surface Water 52116.2.8 Other Applications of Chlorine 52216.2.9 Dechlorination 52216.3 Chloramines 52316.4 Chlorine Dioxide 52416.4.1 Chlorine Dioxide Doses as a Primary Disinfectant 52516.4.2 Chlorine Dioxide for Pre-disinfection or for Residual Disinfection 52516.4.3 Generation of Chlorine Dioxide 52616.5 Peracids: Peracetic Acid (PAA) and Performic Acid (PFA) 52716.5.1 Peracetic Acid 527Kinetics of Disinfection Using PAA 528Measuring PAA Residuals 529Applications for Wastewater Disinfection 530Chemical Disinfection Process Control 53016.5.2 Performic Acid 53116.6 Ozone 53116.6.1 Determining the Appropriate Ozone Dose 53216.6.2 Ozone Generation 53316.6.3 Ozone Dissolution Systems 53416.6.4 Ozone Contactor Basins 53516.6.5 Ozone Chemistry: Mass Transfer Coefficients and Radicals Production 53616.6.6 Ozone for Wastewater Disinfection 53716.6.7 Ozone for Destruction of Micropollutants 53816.7 Ultraviolet Radiation 53816.7.1 Mechanism of UV Disinfection 53816.7.2 Repair of UV Damage 539Photo Repair 539Dark Repair 54016.7.3 Interferences 54016.7.4 Generation of Ultraviolet Light and Ultraviolet Reactors 54116.7.5 Disinfection Kinetics 54116.7.6 Disinfection Doses (or Fluences) 54216.7.7 Determination of UV Fluence 54216.7.8 Ultraviolet Reactors 54516.8 Point-of-use Disinfectants: Solar Disinfection (SODIS), with or without Photoreactants such as TiO2 54716.9 Disinfection Byproducts 54816.9.1 Chlorine 54916.9.2 Chloramines 54916.9.3 Chlorine Dioxide 55016.9.4 Peracids 55016.9.5 Ozone 55016.9.6 Ultraviolet 55116.9.7 Comparative Risks 55116.10 Disinfection to Combat Invasive Species 551Questions and Problems 553References 556Section V: Biological Wastewater Treatment 56517 Aerobic Biological Treatment: Biotreatment Processes 56717.1 Microorganisms in Aerobic Biological Treatment 56717.2 The Activated Sludge Process 56817.3 Substrate Removal and Growth of Microorganisms 56917.3.1 Substrate Removal 569Temperature Dependence of Rate Coefficients 571BOD, COD, and TOC Removal 57117.3.2 Growth of Microorganisms and Biological Sludge Production 572Sludge Composition and Nutrient Requirements 57317.4 Activated Sludge Configurations 57417.4.1 Definition of Symbols for the Activated Sludge Process Models 57517.4.2 Reactor 57717.4.3 System Effluent and Waste Sludge Line 57717.4.4 Clarifier 57717.5 Process Analysis 57817.5.1 Physical Concentration of Solids in the Bioreactor 57817.5.2 Solids Retention Time 58017.5.3 Sludge Volume Index 58017.5.4 CM Reactor Without Recycle 582Substrate Balance 582Biomass Balance 58317.5.5 CM Reactor with Recycle 585Biomass Balance 58517.5.6 Application of the Basic Model in the Historical Context 586Frailties of the Historical Models 59017.5.7 Matrix Representation of the Basic (Soluble Substrate) Model 59117.5.8 The Rate of Recycle 59317.5.9 Food-to-Microorganism Ratio and SRT 59417.6 Advanced Model for Carbon Removal 59617.6.1 Total Effluent COD from the Process 59917.6.2 Removal of Influent Particulate Organic Matter 59917.6.3 Estimation of Parameters and Calibration of the Advanced Model 60017.6.4 Calibration of Models to Existing Data 60217.7 Sludge Production in Activated Sludge Systems 60417.8 Plug Flow Activated Sludge Treatment 60717.9 Variations of the Activated Sludge Process 60917.9.1 Sequencing Batch Reactors 60917.9.2 Extended Aeration 61217.10 Other Activated Sludge Process Variations 61317.10.1 Pure Oxygen Activated Sludge Process 61517.10.2 Powdered Activated Carbon Activated Sludge Process 615Design Parameters and Operating Conditions for Activated Sludge Processes 61517.11 Design of Activated Sludge Processes for Nitrogen and Phosphorus Removal 61617.11.1 Nitrogen Transformations 616Nitrogen Removal-Denitrification 62117.11.2 Advanced Denitrification Processes 626SHARON Process 626Anammox Process 627Other Processes 62817.11.3 Enhanced Phosphorus Uptake 628Fermentation of Primary or Activated Sludge 630Phostrip and Bardenpho Bio-P Processes 63217.12 Operating Characteristics of Activated Sludge Processes 63217.12.1 SRT and Characteristics of Waste Activated Sludge 63217.13 Granular Activated Sludge and Membrane Processes 63417.13.1 Granular Activated Sludge Processes 63417.13.2 Membrane Activated Sludge Processes 635Design of Submerged Membrane Reactors 63717.14 Fixed-Film Activated Sludge Processes 63917.14.1 Integrated Fixed-Film Activated Sludge and Moving Bed Bioreactor Processes 639Design of MBBRs 64117.14.2 Biologically Activated Filters 645Design of Biological Active Filters 64717.14.3 Rotating Biological Contact Units 64817.15 Fixed-Film Trickling Filter Processes 65017.15.1 Trickling Filters 650Sludge Production from Trickling Filters 656Air Supply in Trickling Filters 656Operation of Trickling Filters 66017.15.2 Hydraulic Design of Distributors for Trickling Filters 66017.16 Oxygen Uptake in Activated Sludge Processes 66317.17 Metals Removal in Activated Sludge Processes 66417.18 Aerobic Sludge Digestion 66417.18.1 Model for Aerobic Sludge Digestion 665Oxygen Uptake in Aerobic Digestion 668Rate Constants and Sludge Degradability 66817.18.2 Thermophilic Aerobic Digestion 669Pre-treatment for Aerobic Sludge Digestion 67217.18.3 Indicator Microorganism Reduction in Aerobic Digestion 672Questions and Problems 673References 68018 Aerobic Biological Treatment: Other Process Operations 68918.1 Aeration in Biological Wastewater Treatment 68918.1.1 Aeration Devices in Wastewater Treatment 692Diffused Aerators 692Surface and Other Aerators 69218.2 Post-aeration Systems for Wastewater Treatment 69718.2.1 Diffused Aeration Systems 69718.2.2 Cascades 69918.2.3 Weirs 69918.3 Type III Sedimentation: Zone Settling 70018.3.1 Design of a Basin for Type III Sedimentation 703Gravity Flux 703Underflow Flux 70418.3.2 Secondary Clarifier Design 70818.3.3 Modeling for Secondary Clarifier and Operation 70918.3.4 Membrane Separation of Solids 711Lamella Clarifiers 71218.4 Sludge Settling Problems and Foaming 71218.4.1 Microorganisms 71218.4.2 Selectors and Process Operating Conditions 713Questions and Problems 715References 71819 Anaerobic Wastewater Treatment 721History 72119.1 Anaerobic Metabolism 72219.1.1 Hydrolysis 72219.1.2 Acid Formation: Acidogenesis and Acetogenesis 72319.1.3 Methanogenesis 72419.1.4 Other Metabolic Pathways 72519.1.5 Environmental Variables 725Oxidation-Reduction Potential 725Temperature 725pH 725Mixing 726Ammonia and Sulfide Control 726Nutrient Requirements 72719.2 Process Fundamentals 72719.2.1 Solids Yield and Retention Time 72719.2.2 Biogas Potential 729Biochemical Methane Potential and Anaerobic Toxicity Assay 729Methane Production in Anaerobic Treatment 730Dissolved Methane 731Biogas Utilization 73219.3 Process Analysis 73219.3.1 Definition of Symbols for the Anaerobic Models 73319.3.2 General Model for an Anaerobic Process 734Anaerobic Reactor Receiving Only Particulate Substrate 734Anaerobic Reactor Receiving Only Soluble Substrate 737The Traditional Digester Sizing Equation for Anaerobic Sludge Digesters 73719.3.3 Advanced Model for an Anaerobic Process 740Substrate Removal and Biomass Accumulation 741Temperature Effects on Rate Coefficients 74719.4 Misconceptions and Barriers about Anaerobic Treatment 74719.5 Anaerobic Treatment Processes 75019.5.1 Conventional Anaerobic Treatment 75019.5.2 Contact Process 75319.5.3 Upflow Anaerobic Sludge Blanket Reactor 75419.5.4 Fixed-Film Reactors 756Upflow Fixed-Film Reactors 757Downflow Fixed-Film Reactors 758Fluidized Bed Reactors 75919.5.5 Two-Phase Anaerobic Digestion 75919.5.6 Thermophilic Digestion 76019.5.7 Membrane Anaerobic Treatment 76019.5.8 Pre-treatment of Sludge for Anaerobic Digestion of Biosolids 76019.6 Anaerobic Digestion of Municipal Solid Waste 76219.7 Process Stability and Monitoring 76319.7.1 Chemical Precipitation Problems in Anaerobic Digesters 76419.7.2 Recovery of Nutrients through Struvite Harvesting 76419.7.3 Sludge Production 76619.7.4 Anaerobic Treatment of Low-Strength Wastes 76619.8 Comparison of Anaerobic and Aerobic Treatment Processes 76719.8.1 Pollutant Removal Efficiency 76819.8.2 Number and Size of Operations 76819.8.3 Energy and Chemical Inputs 76919.8.4 Heat Exchanger 77019.9 Energy Assessment of Anaerobic and Aerobic Treatment 774Anaerobic Versus Aerobic Treatment 776Calculation of the Energy Potential of a Waste 77719.10 Pathogen Reduction in Anaerobic Processes 777Questions and Problems 778References 78120 Treatment in Ponds and Land Systems 78920.1 Overview of Stabilization Ponds 78920.1.1 Pond Operation 79020.1.2 Pond Effluent Quality 79120.2 Pond Types 79220.3 Design of Pond Systems 79520.3.1 Design of Ponds in the Far North 79620.3.2 Models for Facultative Ponds 79820.3.3 Nitrogen and Phosphorus Removal 79820.3.4 Heat Balance for Ponds 79920.4 Removal of Suspended Solids from Pond Effluents 80020.5 Indicator Microorganism Die-off in Ponds 80120.6 Aerated Lagoons 80220.7 Treatment of Wastewater in Land Systems 80420.7.1 Land Treatment of Wastewater 804Measurement of Hydraulic Conductivity 805Wastewater Constituents Influencing Land Treatment 80720.7.2 Slow Rate Land Application Systems 80720.7.3 Soil Aquifer Treatment 81420.7.4 Overland Flow Systems 815Questions and Problems 817References 819Section VI: Final Disposal and Impact Analysis 82321 Sludge Processing and Land Application 82521.1 Sludge Characteristics and Conditioning 825Sludge Density 825Sludge Viscosity 82721.2 Sludge Generation and Treatment Processes 82821.3 Sludge Conditioning 83321.4 Sludge Thickening 83621.4.1 Gravity Thickening 83621.4.2 Flotation Thickening 83721.5 Mechanical Sludge Dewatering 83921.5.1 Centrifugation 84021.5.2 Vacuum Dewatering 84321.5.3 Plate Pressure Filters 84621.6 Land Application of Sludge 847Questions and Problems 854References 85622 Effluent Disposal in Natural Waters 85922.1 Pollutants in Natural Waters 85922.1.1 Water Quality Indices 859Fish Survival and Temperature 862Nutrient Loadings to Lakes 86422.2 Loading Equations for Streams 86522.2.1 Pollutant Decay in Streams 86522.2.2 Conservative Substance 866Point Source 866Distributed Source 86622.2.3 Substances That Are Transformed by One Reaction 866Point Source 866Distributed Source 86722.3 Dissolved Oxygen Variation in a Stream 87022.3.1 Nitrification in Natural Waters 87322.3.2 Factors Affecting the Dissolved Oxygen Sag Curve 87422.3.3 The Reaeration Rate Coefficient 87722.3.4 Reaeration at Dams 87822.4 Combined Sewer Overflows Abatement 878Questions and Problems 881References 88323 Life Cycle Analysis 88723.1 Historical Development of LCA 88823.2 Why Use LCA
 What Are the Objectives
 What Are Its Benefits and What Does It Not Do? 88823.3 ISO Standards 14040 and 14044 88923.4 Definitions of Terms in ISO 14040 and 14044 88923.5 Principles Established by ISO 14040 89023.6 Key Components of the ISO Standards 89123.6.1 Goal and Scope 89223.6.2 System Boundaries 892Life Cycle Inventory Analysis 89323.6.3 Life Cycle Impact Assessment 894Selection of Impact Categories, Category Indicators, and Characterization Models 894Assignment of LCI Results to the Selected Impact Categories (Classification) 895Calculation of Category Indicator Results (Characterization) 895Characterization Factors, Midpoints and Endpoints 896Optional Elements of the LCIA 89723.6.4 Limitations of LCIA 89823.6.5 Interpretation 89823.7 Software and Databases 89923.8 Examples of Case Studies of LCA in Water and Wastewater Treatment Projects 899Questions and Problems 906References 909Appendix A 913Author Index 927Subject Index 937