Written by one of the world's foremost authorities on the subject, this is the most comprehensive and in-depth treatment available to environmental engineers and scientists for the remediation of groundwater, one of the earth's most precious resources.
Groundwater is one of the Earth's most precious resources. We use it for drinking, bathing, and many other purposes. Without clean water, humans would cease to exist. Unfortunately, because of ignorance or lack of caring, groundwater is often contaminated through industrialization, construction or any number of other ways. It is the job of the environmental engineer to remediate the contaminated groundwater and make what has been tainted safe again.Selecting the proper remediation strategy and process is the key to moving forward, and, once this process has been selected, it must be executed properly, taking into consideration the costs, the type of contaminants that are involved, time frames, and many other factors.
This volume provides a broad overview of the current and most widely applied remedial strategies. Instead of discussing these strategies in a generic way, the volume is organized by focusing on major contaminants that are of prime focus to industry and municipal water suppliers. The specific technologies that are applicable to the chemical contaminants discussed in different chapters are presented, but then cross-referenced to other chemical classes or contaminants that are also candidates for the technologies. The reader will also find extensive cost guidance in this volume to assist in developing preliminary cost estimates for capital equipment and operations & maintenance costs, which should be useful in screening strategies.
The eight chapters cover all of the major various types of contaminants and their industrial applications, providing a valuable context to each scenario of contamination. This is the most thorough and up-to-date volume available on this important subject, and it is a must-have for any environmental engineer or scientist working in groundwater remediation.
Table of Contents
Preface xi
About the Author xv
1 Conducting Groundwater Quality Investigations 1
1.1 Introduction 1
1.2 Evolution of Site Assessments 2
1.3 Technology Limitations and Cleanup Goals 14
1.4 Conceptual Models 14
1.4.1 Source and Release Information 15
1.4.2 Geologic and Hydrogeologic Characterization 16
1.4.3 Contaminant Distribution, Transport and Fate 17
1.4.4 Geochemistry Impacting Natural Biodegradation 17
1.5 Risk Assessment Concepts 18
1.6 Institutional Controls 20
1.7 Risk-Based Cleanup Goals and Screening Level Evaluations 20
1.8 Assessing Plume Migration Potential 25
2 The Family of DNAPLs 37
2.1 Defining DNAPL 37
2.2 Chemicals and Origins 38
2.2.1 Creosote and Coal Tars 38
2.2.2 Polychlorinated Biphenyls 41
2.2.3 Chlorinated Solvents 44
2.2.4 Mixtures 48
2.3 DNAPL Behavior 49
2.3.1 General Behavior and Concepts 49
2.3.2 Important Parameters for Site Characterization 56
2.4 Overview of Remediation Strategies 59
2.4.1 Remediation Goals 59
2.4.2 Technologies 63
2.4.2.1 Pump-and-Treat 63
2.4.2.2 Permeable Reactive Barriers 63
2.4.2.3 Physical Barriers 64
2.4.2.4 Enhanced Biodegradation 64
2.4.2.5 Thermal Technologies 64
2.4.2.6 Chemical Flushing 65
2.4.2.7 Excavation and Removal 65
2.4.2.8 Soil Vacuum Extraction 66
2.4.2.9 Water Flooding 66
2.4.2.10 Air Sparging 66
3 Hydrocarbons 69
3.1 Fate and Transport 69
3.1.1 General 69
3.1.2 Advective Transport 70
3.1.3 Dispersion 70
3.1.4 Sorption 71
3.1.5 Dilution and Recharge 73
3.1.6 Volatilization 73
3.2 Gasoline Compounds 74
3.2.1 General Description 74
3.2.2 The BTEX Compounds and MTBE 74
3.2.3 Properties of VOCs 75
3.2.4 Degradation 75
3.2.5 Half-Lifes 77
3.3 Pump and Treat 79
3.3.1 Concept 79
3.3.2 Non-Aqueous Phase Liquids 85
3.3.3 Contaminant Desorption and Precipitate Dissolution 86
3.3.4 Remedial Technologies 87
3.3.5 EPA Cost Data for Pump-and-Treat 89
4 1,4-Dioxane 95
4.1 Overview 95
4.2 Properties, Fate and Transport 98
4.3 Health Effects and Regulations 103
4.4 Remediation Technologies 104
4.4.1 Advanced Oxidation (Ex Situ) 109
4.4.2 Adsorption (GAC) (Ex Situ) 113
4.4.3 Bioremediation 113
4.4.4 Treatment in Soil 114
5 Perfluorinated Compounds (PFCS) 117
5.1 Overview 117
5.2 Origins of the Contaminants 118
5.3 PFAs Properties and Structures 121
5.3.1 General Description 121
5.3.2 Variations of PFAS 123
5.3.3 PFOS 126
5.3.4 PFOA 129
5.4 Environmental Fate and Transport 130
5.5 Groundwater Contamination 144
5.6 Water Treatment 149
5.7 Estimating Carbon Treatement Costs 157
6 Chlorinated Solvents 163
6.1 Physico-Chemical Properties of Chlorinated Solvents 163
6.2 Origins of Groundwater Contamination 167
6.3 Fate and Transport 168
6.3.1 Properties 168
6.3.2 Degradation and Daughter Products 170
6.3.3 Biodegradation Half-Life 173
6.3.4 DNAPL Migration 185
6.4 Groundwater Remediation Strategies 188
6.4.1 Preliminary Considerations 188
6.4.2 Soil Excavation, Treatment and Disposal 195
6.4.3 Soil Vapor Extraction 197
6.4.4 Enhanced Methods of Soil Vapor Extraction 201
6.4.5 In Situ Air Sparging 202
6.4.6 Enhanced Biodegradation 210
6.4.7 In-well Aeration and Recirculation 215
6.4.8 Reactive and Permeable Walls 216
6.5 Costs 217
6.5.1 Soil Excavation, Treatment and Disposal 217
6.5.2 Soil Vapor Extraction 220
6.5.3 Air Sparging Comparisons to other Technologies 227
7 Mineral Ions and Natural Groundwater Contaminants 233
7.1 Overview 233
7.2 Secondary Drinking Water Standards 236
7.3 Irrigation Water Quality Standards 238
7.3.1 Salts 238
7.3.2 Water Analysis Terminology 238
7.3.3 Types of Salt Problems 239
7.3.4 Salinity Hazard 241
7.3.5 Sodium Hazard 242
7.3.6 Trace Elements and Limits 242
7.4 Water Treatment Membrane Technologies 247
7.4.1 Overview 247
7.4.2 Reverse Osmosis (RO) 248
7.4.3 Nanofiltration 255
7.4.4 Microfiltration 258
7.4.5 Ultrafiltration 260
7.4.6 Treatment Costs 262
7.4.7 Secondary Wastes 265
7.4.8 Selection Criteria 265
7.5 Ion Exchange 266
7.5.1 Technology Description 266
7.5.2 Chelating Agents 271
7.5.3 Batch and Column Exchange Systems 272
7.5.4 Process Equipment 272
7.5.5 Cost Data 275
7.6 Crystallization 279
7.6.1 Technology Description 279
7.6.2 Forced-Circulation Crysallizers 286
7.6.3 Draft-tube Crystallizers and Draft-tube-baffle Crystallizers 288
7.6.4 Surface-Cooled Crystallizers 289
7.6.5 Oslo Crystallizers 291
7.6.6 Fluid-Bed Type Crystallizers 292
8 Heavy Metals and Mixed Media Remediation Technologies for Contaminated Soils and Groundwater 299
8.1 Nature of the Problem 299
8.2 Toxic Metal Chemical Forms, Speciation and Properties 300
8.3 Remedial Technology Strategies 306
8.3.1 Isolation 306
8.3.2 Capping 306
8.3.3 Subsurface Barriers 313
8.3.4 Immobilization 315
8.3.5 Solidification/Stabilization 317
8.3.6 Vitrification 321
8.3.7 Toxicity and Mobility Reduction 323
8.3.8 Wet Oxidation Process 331
8.3.9 Advanced Oxidation Technologies 333
8.3.10 Permeable Treatment Walls 343
8.3.11 Biological Treatment 344
8.3.12 Physical Separation 346
8.3.13 Extraction 349
8.3.14 Soil Washing 349
8.3.15 Soil Screening 350
8.3.16 Chemical Treatment 350
8.3.17 Physical Treatment 351
8.3.18 Pyrometallurgical Extraction 352
8.3.19 In Situ Soil Flushing 352
8.3.20 Electrokinetic Treatment 352
8.4 Cost Data 353
8.4.1 General Cost Information 353
8.4.2 Site Capping 356
8.4.3 In situ Solidification/Stabilization 358
8.4.4 Ex Situ Solidification/Stabilization 361
8.4.5 Soil Washing 365
8.4.6 Slurry Walls 367
Index 379
