A comprehensive guide to sludge management, reuse, and disposal
When wastewater is treated, reducing organic material to carbon dioxide, water, and bacterial cellsthe cells are disposed of, producing a semisolid and nutrient-rich byproduct called sludge. The expansion in global population and industrial activity has turned the production of excess sludge into an international environmental challenge, with the ultimate disposal of excess sludge now one of the most expensive problems faced by wastewater facilities.
Written by two leading environmental engineers, Biological Sludge Minimization and Biomaterials/Bioenergy Recovery Technologies offers a comprehensive look at cutting-edge techniques for reducing sludge production, converting sludge into a value-added material, recovering useful resources from sludge, and sludge incineration. Reflecting the impact of new stringent environmental legislation, this book offers a frank appraisal of how sludge can be realistically managed, covering key concerns and the latest tools:
- Fundamentals of biological processes for wastewater treatment, wastewater microbiology, and microbial metabolism, essential to understanding how sludge is produced
- Prediction of primary sludge and waste-activated sludge production, among the chief design and operational challenges of a wastewater treatment plant
- Technologies for sludge reduction, with a focus on reducing microbial growth yield as well as enhancing sludge disintegration
- The use of anerobic digestion of sewage sludge for biogas recovery, in terms of process fundamentals, design, and operation
- The use of the microbial fuel cell (MFC) system for the sustainable treatment of organic wastes and electrical energy recovery
Table of Contents
Preface xvii
Contributors xxi
1 Fundamentals of Biological Processes for Wastewater Treatment 1
Jianlong Wang
1.1 Introduction, 1
1.2 Overview of Biological Wastewater Treatment, 2
1.2.1 The Objective of Biological Wastewater Treatment, 2
1.2.2 Roles of Microorganisms in Wastewater Treatment, 3
1.2.3 Types of Biological Wastewater Treatment Processes, 4
1.3 Classification of Microorganisms, 4
1.3.1 By the Sources of Carbon and Energy, 4
1.3.2 By Temperature Range, 6
1.3.3 Microorganism Types in Biological Wastewater Treatment, 7
1.4 Some Important Microorganisms in Wastewater Treatment, 8
1.4.1 Bacteria, 8
1.4.2 Fungi, 12
1.4.3 Algae, 15
1.4.4 Protozoans, 16
1.4.5 Rotifers and Crustaceans, 18
1.4.6 Viruses, 20
1.5 Measurement of Microbial Biomass, 21
1.5.1 Total Number of Microbial Cells, 21
1.5.2 Measurement of Viable Microbes on Solid Growth Media, 22
1.5.3 Measurement of Active Cells in Environmental Samples, 23
1.5.4 Determination of Cellular Biochemical Compounds, 24
1.5.5 Evaluation of Microbial Biodiversity by Molecular Techniques, 24
1.6 Microbial Nutrition, 24
1.6.1 Microbial Chemical Composition, 25
1.6.2 Macronutrients, 27
1.6.3 Micronutrients, 28
1.6.4 Growth Factor, 29
1.6.5 Microbial Empirical Formula, 31
1.7 Microbial Metabolism, 31
1.7.1 Catabolic Metabolic Pathways, 32
1.7.2 Anabolic Metabolic Pathway, 38
1.7.3 Biomass Synthesis Yields, 39
1.7.4 Coupling Energy-Synthesis Metabolism, 41
1.8 Functions of Biological Wastewater Treatment, 42
1.8.1 Aerobic Biological Oxidation, 42
1.8.2 Biological Nutrients Removal, 45
1.8.3 Anaerobic Biological Oxidation, 50
1.8.4 Biological Removal of Toxic Organic Compounds and Heavy Metals, 55
1.8.5 Removal of Pathogens and Parasites, 58
1.9 Activated Sludge Process, 59
1.9.1 Basic Process, 60
1.9.2 Microbiology of Activated Sludge, 61
1.9.3 Biochemistry of Activated Sludge, 66
1.9.4 Main Problems in the Activated Sludge Process, 67
1.10 Suspended- and Attached-Growth Processes, 69
1.10.1 Suspended-Growth Processes, 69
1.10.2 Attached-Growth Processes, 70
1.10.3 Hybrid Systems, 71
1.10.4 Comparison Between Suspended- and Attached-Growth Systems, 72
1.11 Sludge Production, Treatment and Disposal, 74
1.11.1 Sludge Production, 74
1.11.2 Sludge Treatment Processes, 76
1.11.3 Sludge Disposal and Application, 78
References, 79
2 Sludge Production: Quantification and Prediction for Urban Treatment Plants and Assessment of Strategies for Sludge Reduction 81
Mathieu Spe´randio, Etienne Paul, Yolaine Bessie`re, and Yu Liu
2.1 Introduction, 81
2.2 Sludge Fractionation and Origin, 82
2.2.1 Sludge Composition, 82
2.2.2 Wastewater Characteristics, 83
2.3 Quantification of Excess Sludge Production, 88
2.3.1 Primary Treatment, 88
2.3.2 Activated Sludge Process, 90
2.3.3 Phosphorus Removal (Biological and Physicochemical), 97
2.4 Practical Evaluation of Sludge Production, 99
2.4.1 Sludge Production Yield Variability with Domestic Wastewater, 99
2.4.2 Influence of Sludge Age: Experimental Data Versus Models, 100
2.4.3 ISS Entrapment in the Sludge, 103
2.4.4 Example of Sludge Production for a Different Case Study, 104
2.5 Strategies for Excess Sludge Reduction, 106
2.5.1 Classification of Strategies, 106
2.5.2 Increasing the Sludge Age, 107
2.5.3 Model-Based Evaluation of Advanced ESR Strategies, 109
2.6 Conclusions, 111
2.7 Nomenclature, 112
References, 114
3 Characterization of Municipal Wastewater and Sludge 117
Etienne Paul, Xavier Lefebvre, Mathieu Sperandio, Dominique Lefebvre, and Yu Liu
3.1 Introduction, 117
3.2 Definitions, 119
3.3 Wastewater and Sludge Composition and Fractionation, 120
3.3.1 Wastewater COD Fractions, 121
3.3.2 WAS COD Fractions, 122
3.3.3 ADS Organic Fractions, 122
3.4 Physical Fractionation, 123
3.4.1 Physical State of Wastewater Organic Matter, 123
3.4.2 Methods for Physical Fractionation of Wastewater Components, 123
3.5 Biodegradation Assays for Wastewater and Sludge Characterization, 124
3.5.1 Background, 124
3.5.2 Methods Based on Substrate Depletion, 125
3.5.3 Methods Based on Respirometry, 125
3.5.4 Anaerobic Biodegradation Assays, 128
3.6 Application to Wastewater COD Fractionation, 131
3.6.1 Global Picture of Fractionation Methods and Wastewater COD Fractions, 131
3.6.2 Application of Physical Separation for Characterization of Wastewater COD Fractions, 132
3.6.3 Biodegradable COD Fraction, 133
3.6.4 Relation Between Physical and Biological Properties of Organic Fractions, 136
3.6.5 Unbiodegradable Particulate COD Fractions, 137
3.7 Assessment of the Characteristics of Sludge and Disintegrated Sludge, 143
3.7.1 Physical Fractionation of COD Released from Sludge Disintegration Treatment, 143
3.7.2 Biological Fractionation of COD Released from Sludge Disintegration Treatment, 145
3.7.3 Biodegradability of WAS in Anaerobic Digestion, 145
3.7.4 Unbiodegradable COD in Anaerobic Digestion, 146
3.8 Nomenclature, 147
References, 149
4 Oxic-Settling-Anaerobic Process for Enhanced Microbial Decay 155
Qingliang Zhao and Jianfang Wang
4.1 Introduction, 155
4.2 Description of the Oxic-Settling-Anaerobic Process, 156
4.2.1 Oxic-Settling-Anaerobic Process, 156
4.2.2 Characteristics of the OSA Process, 157
4.3 Effects of an Anaerobic Sludge Tank on the Performance of an OSA System, 158
4.3.1 Fate of Sludge Anaerobic Exposure in an OSA System, 158
4.3.2 Effect of Sludge Anaerobic Exposure on Biomass Activity, 160
4.4 Sludge Production in an OSA System, 161
4.5 Performance of an OSA System, 162
4.5.1 Organic and Nutrient Removal, 162
4.5.2 Sludge Settleability, 163
4.6 Important Influence Factors, 164
4.6.1 Influence of the ORP on Sludge Production, 164
4.6.2 Influence of the ORP on Performance of an OSA System, 164
4.6.3 Influence of SAET on Sludge Production, 166
4.6.4 Influence of SAET on the Performance of an OSA System, 166
4.7 Possible Sludge Reduction in the OSA Process, 166
4.7.1 Slow Growers, 167
4.7.2 Energy Uncoupling Metabolism, 167
4.7.3 Sludge Endogenous Decay, 169
4.8 Microbial Community in an OSA System, 171
4.8.1 Staining Analysis, 172
4.8.2 FISH Analysis, 173
4.9 Cost and Energy Evaluation, 174
4.10 Evaluation of the OSA Process, 175
4.11 Process Development, 176
4.11.1 Sludge Decay Combined with Other Sludge Reduction Mechanisms, 176
4.11.2 Improved Efficiency in Sludge Anaerobic Digestion, 177
4.11.3 Combined Minimization of Excess Sludge with Nutrient Removal, 178
References, 179
5 Energy Uncoupling for Sludge Minimization: Pros and Cons 183
Bo Jiang, Yu Liu, and Etienne Paul
5.1 Introduction, 183
5.2 Overview of Adenosine Triphosphate Synthesis, 184
5.2.1 Electron Transport System, 184
5.2.2 Mechanisms of Oxidative Phosphorylation, 185
5.3 Control of ATP Synthesis, 187
5.3.1 Diversion of PMF from ATP Synthesis to Other Physiological Activities, 187
5.3.2 Inhibition of Oxidative Phosphorylation, 187
5.3.3 Uncoupling of Electron Transport and Oxidative Phosphorylation, 188
5.4 Energy Uncoupling for Sludge Reduction, 189
5.4.1 Chemical Uncouplers Used for Sludge Reduction, 189
5.4.2 Uncoupling Activity, 198
5.5 Modeling of Uncoupling Effect on Sludge Production, 200
5.6 Sideeffects of Chemical Uncouplers, 202
5.7 Full-Scale Application, 204
References, 204
6 Reduction of Excess Sludge Production Using Ozonation or Chlorination: Performance and Mechanisms of Action 209
Etienne Paul, Qi-Shan Liu, and Yu Liu
6.1 Introduction, 209
6.2 Significant Operational Results for ESP Reduction with Ozone, 210
6.2.1 Options for Combining Ozonation and Biological Treatment, 210
6.2.2 ESP Reduction Performance, 212
6.2.3 Assessing Ozone Efficiency for Mineral ESP Reduction, 215
6.3 Side Effects of Sludge Ozonation, 216
6.3.1 Outlet SS and COD, 216
6.3.2 N Removal, 218
6.4 Cost Assessment, 221
6.5 Effect of Ozone on Sludge, 222
6.5.1 Synergy Between Ozonation and Biological Treatment, 222
6.5.2 Some Fundamentals of Ozone Transfer, 222
6.5.3 Sludge Composition, 224
6.5.4 Effect of Ozone on Activated Sludge: Batch Tests, 226
6.5.5 Effect of Ozone on Biomass Activity, 228
6.5.6 Competition for Ozone in Mixed Liquor, 231
6.6 Modeling Ozonation Effect, 233
6.7 Remarks on Sludge Ozonation, 236
6.8 Chlorination in Water and Wastewater Treatment, 236
6.8.1 Introduction, 236
6.8.2 Chlorination-Assisted Biological Process for Sludge Reduction, 237
6.8.3 Effect of Chlorine Dosage on Sludge Reduction, 239
6.8.4 Chlorine Requirement, 240
6.9 Nomenclature, 242
References, 244
7 High-Dissolved-Oxygen Biological Process for Sludge Reduction 249
Zhi-Wu Wang
7.1 Introduction, 249
7.2 Mechanism of High-Dissolved-Oxygen Reduced Sludge Production, 251
7.2.1 High-Dissolved-Oxygen Decreased Specific Loading Rate, 251
7.2.2 High-Dissolved-Oxygen Uncoupled Microbial Metabolism Pathway, 252
7.2.3 High-Dissolved-Oxygen Shifted Microbial Population, 254
7.3 Limits of High-Dissolved-Oxygen Process for Reduced Sludge Production, 255
References, 256
8 Minimizing Excess Sludge Production Through Membrane Bioreactors and Integrated Processes 261
Philip Chuen-Yung Wong
8.1 Introduction, 261
8.2 Mass Balances, 262
8.3 Integrated Processes Based on Lysis-Cryptic Growth, 266
8.3.1 Mass Balance Incorporating Sludge Disintegration and Solubilization, 268
8.3.2 Thermal and Thermal-Alkaline Treatment, 274
8.3.3 Ozonation, 276
8.3.4 Sonication, 279
8.4 Predation, 283
8.5 Summary and Concluding Remarks, 285
References, 286
9 Microbial Fuel Cell Technology for Sustainable Treatment of Organic Wastes and Electrical Energy Recovery 291
Shi-Jie You, Nan-Qi Ren, and Qing-Liang Zhao
9.1 Introduction, 291
9.2 Fundamentals, Evaluation, and Design of MFCs, 293
9.2.1 Principles, 293
9.2.2 Performance Evaluation, 293
9.2.3 MFC Configurations, 294
9.3 Performance of Anodes, 295
9.3.1 Electrode Materials, 295
9.3.2 Microbial Electron Transfer, 296
9.3.3 Electron Donors, 298
9.4 Cathode Performances, 299
9.4.1 Electron Acceptors, 300
9.4.2 Electrochemical Fundamentals of the Oxygen Reduction Reaction, 302
9.4.3 Air-Cathode Structure and Function, 303
9.4.4 Electrocatalyst, 304
9.5 Separator, 306
9.6 pH Gradient and Buffer, 307
9.7 Applications of MFC-Based Technology, 309
9.7.1 Biosensors, 309
9.7.2 Hydrogen Production, 310
9.7.3 Desalination, 310
9.7.4 Hydrogen Peroxide Synthesis, 312
9.7.5 Environmental Remediation, 312
9.8 Conclusions and Remarks, 314
References, 315
10 Anaerobic Digestion of Sewage Sludge 319
Kuan-Yeow Show, Duu-Jong Lee, and Joo-Hwa Tay
10.1 Introduction, 319
10.2 Principles of Anaerobic Digestion, 320
10.2.1 Hydrolysis and Acidogenesis, 321
10.2.2 Methane Formation, 323
10.3 Environmental Requirements and Control, 324
10.3.1 pH, 324
10.3.2 Alkalinity, 325
10.3.3 Temperature, 326
10.3.4 Nutrients, 326
10.3.5 Toxicity, 327
10.4 Design Considerations for Anaerobic Sludge Digestion, 329
10.4.1 Hydraulic Detention Time, 329
10.4.2 Solids Loading, 330
10.4.3 Temperature, 331
10.4.4 Mixing, 331
10.5 Component Design of Anaerobic Digester Systems, 331
10.5.1 Tank Configurations, 331
10.5.2 Temperature Control, 333
10.5.3 Sludge Heating, 333
10.5.4 Auxiliary Mixing, 334
10.6 Reactor Configurations, 336
10.6.1 Conventional Anaerobic Digesters, 336
10.6.2 Anaerobic Contact Processes, 338
10.6.3 Other Types of Configurations, 340
10.7 Advantages and Limitations of Anaerobic Sludge Digestion, 343
10.8 Summary and New Horizons, 344
References, 345
11 Mechanical Pretreatment-Assisted Biological Processes 349
He´le`ne Carre`re, Damien J. Batstone, and Etienne Paul
11.1 Introduction, 349
11.2 Mechanisms of Mechanical Pretreatment, 350
11.2.1 From Sludge Disintegration to Cell Lysis and Chemical Transformation, 350
11.2.2 Specific Energy, 350
11.2.3 Sonication, 351
11.2.4 Grinding, 353
11.2.5 Shear-Based Methods: High-Pressure and Collision Plate Homogenization, 353
11.2.6 Lysis Centrifuge, 353
11.3 Impacts of Treatment: Rate vs. Extent of Degradability, 353
11.3.1 Grinding, 354
11.3.2 Ultrasonication, 354
11.4 Equipment for Mechanical Pretreatment, 354
11.4.1 Sonication, 355
11.4.2 Grinding, 357
11.4.3 Shear-Based Methods: High-Pressure and Collision Plate Homogenization, 358
11.4.4 Lysis Centrifuge, 359
11.5 Side Effects, 359
11.6 Mechanical Treatment Combined with Activated Sludge, 360
11.7 Mechanical Treatment Combined with Anaerobic Digestion, 361
11.7.1 Performances, 361
11.7.2 Dewaterability, 363
11.7.3 Full-Scale Performance and Market Penetration, 364
11.7.4 Energy Balance, 365
11.7.5 Nutrient Release and Recovery/Removal, 366
11.8 Conclusion, 367
References, 368
12 Thermal Methods to Enhance Biological Treatment Processes 373
Etienne Paul, He´le`ne Carre`re, and Damien J. Batstone
12.1 Introduction, 373
12.2 Mechanisms, 374
12.2.1 Effects of Heating on Cells, 374
12.2.2 Effect of Heating on Sludge, 376
12.2.3 Mechanisms of Thermal Pretreatment, 388
12.3 Devices for Thermal Treatment, 388
12.3.1 Low-Temperature Pretreatment, 389
12.3.2 High-Temperature Pretreatment, 390
12.4 Applications of Thermal Treatment, 390
12.4.1 Thermal Treatment Combined with Activated Sludge, 390
12.4.2 Thermal Pretreatment to Anaerobic Digestion, 394
12.5 Conclusions, 398
References, 399
13 Combustion, Pyrolysis, and Gasification of Sewage Sludge for Energy Recovery 405
Yong-Qiang Liu, Joo-Hwa Tay, and Yu Liu
13.1 Introduction, 405
13.2 Characteristics and Dewatering of Sewage Sludge, 406
13.3 Energy Recovery from Sludge, 408
13.3.1 Incineration, 408
13.3.2 Pyrolysis and Gasification, 416
13.3.3 Wet Oxidation, 419
13.3.4 Thermal Plasma Pyrolysis and Gasification, 420
References, 421
14 Aerobic Granular Sludge Technology for Wastewater Treatment 429
Bing-Jie Ni and Han-Qing Yu
14.1 Introduction, 429
14.2 Technological Starting Points: Cultivating Aerobic Granules, 431
14.2.1 Substrate Composition, 431
14.2.2 Organic Loading Rate, 433
14.2.3 Seed Sludge, 433
14.2.4 Reactor Configuration, 433
14.2.5 Operational Parameters, 434
14.3 Mechanisms of the Aerobic Granulation Process, 436
14.3.1 Granulation Steps, 436
14.3.2 Selective Pressure, 437
14.4 Characterization of Aerobic Granular Sludge, 438
14.4.1 Biomass Yield and Sludge Reduction, 438
14.4.2 Formation and Consumption of Microbial Products, 440
14.4.3 Microbial Structure and Diversity, 441
14.4.4 Physicochemical Characteristics, 442
14.5 Modeling Granule-Based SBR for Wastewater Treatment, 447
14.5.1 Nutrient Removal in Granule-Based SBRs, 447
14.5.2 Multiscale Modeling of Granule-Based SBR, 450
14.6 Bioremediation of Wastewaters with Aerobic Granular Sludge Technology, 452
14.6.1 Organic Wastewater Treatment, 452
14.6.2 Biological Nutrient Removal, 452
14.6.3 Domestic Wastewater Treatment, 454
14.6.4 Xenobiotic Contaminant Bioremediation, 454
14.6.5 Removal of Heavy Metals or Dyes, 455
14.7 Remarks, 456
References, 457
15 Biodegradable Bioplastics from Fermented Sludge, Wastes, and Effluents 465
Etienne Paul, Elisabeth Neuhauser, and Yu Liu
15.1 Introduction, 465
15.1.1 Context of Poly(hydroxyalkanoate) Production from Sludge and Effluents, 465
15.1.2 Industrial Context for PHA Production, 467
15.2 PHA Structure, 469
15.3 Microbiology for PHA Production, 469
15.4 Metabolism of PHA Production, 471
15.4.1 PHB Metabolism, 472
15.4.2 Metabolism for Other PHA Production, 475
15.4.3 Nutrient Limitations, 476
15.4.4 PHA Metabolism in Mixed Cultures, 477
15.4.5 Effect of Substrate in Mixed Cultures, 478
15.5 PHA Kinetics, 479
15.6 PHA Storage to Minimize Excess Sludge Production in Wastewater Treatment Plants, 481
15.7 Choice of Process and Reactor Design for PHA Production, 482
15.7.1 Criteria, 482
15.7.2 Anaerobic–Aerobic Process, 483
15.7.3 Aerobic Dynamic Feeding Process, 485
15.7.4 Fed-Batch Process Under Nutrient Growth Limitation, 486
15.8 Culture Selection and Enrichment Strategies, 487
15.9 PHA Quality and Recovery, 489
15.10 Industrial Developments, 490
References, 492
Index 499
