Wetland Systems to Control Urban Runoff (eBook)

Front Cover 1
WETLAND SYSTEMS TO CONTROL URBAN RUNOFF 5
Copyright 6
Acknowledgements 7
About the Author 9
Preface 13
Acronyms and Abbreviations 17
Contents 19
Chapter 1 - Water quality standards 29
1.1 Introduction and historical aspects 29
1.2 Water quality standards and treatment objectives 31
1.3 Some thoughts on the standards 32
Chapter 2 - Water treatment 35
2.1 Sources of water 35
2.2 Standard water treatment 35
2.3 Basic water chemistry 37
Chapter 3 - Sewage treatment 39
3.1 Introduction 39
3.2 Design flow rates 40
3.3 Treatment principles 40
3.4 Engineering classification of sewage treatment stages 40
Chapter 4 - Organic effluent 43
4.1 Biochemical oxygen demand 43
4.2 BOD test 44
4.3 Chemical oxygen demand 45
4.4 Other variables used for the characterisation of wastewater 45
Chapter 5 - Stream pollution and effluent standards 47
5.1 Organic stream pollution 47
5.2 Prediction of organic stream pollution 48
5.3 Effluent discharge standard principles 49
Chapter 6 - Preliminary treatment 51
6.1 Introduction 51
6.2 Design of screening units 51
6.3 Design details for screening units 53
6.4 Comminutors 53
6.5 Grit removal 54
Chapter 7 - Primary treatment 57
7.1 Introduction 57
7.2 Loading rate methods 58
7.3 Tank design 58
7.4 Design parameters 59
7.5 Economics of construction 60
7.6 Design details 61
7.7 Hydraulic losses 61
7.8 General design details 62
7.9 Details of various types of sedimentation tanks 62
7.10 Sedimentation aids 65
Chapter 8 - Theory of settling 67
8.1 Introduction 67
8.2 Classification of settling behaviour 67
8.3 Ideal settling 69
Chapter 9 - Coagulation and flocculation 71
9.1 Introduction 71
9.2 Colloidal suspensions 71
9.3 Coagulation processes 73
9.4 Coagulation chemicals 73
9.5 Operation of the coagulation and flocculation process 76
9.6 Rapid mixing 77
9.7 Flocculation 78
Chapter 10 - Sludge blanket clarifiers 79
10.1 Introduction to sludge blanket clarification systems 79
10.2 Types of sludge blanket clarifier 83
10.3 Plate settling in sludge blanket clarifiers 86
Chapter 11 - Flotation systems 87
11.1 Flotation using blown air 87
11.2 Flotation using dissolved air 87
11.3 Flotation units 89
Chapter 12 - Slow filtration 93
12.1 Introduction 93
12.2 Slow sand filtration 93
12.3 Algal actions 98
12.4 Summary of slow sand filtration 100
Chapter 13 - Rapid filtration 101
13.1 Elements of a rapid sand filter 101
13.2 Sand bed 102
13.3 Underdrain system 103
13.4 Hydraulics of filtration 107
13.5 Summary of rapid sand filtration 107
Chapter 14 - Biological treatment 109
14.1 Aerobic self-purification 109
14.2 Waste stabilisation ponds 110
Chapter 15 - Biological filtration 113
15.1 Introduction 113
15.2 Trickling filter 113
15.3 Basic ecology 114
15.4 Process variants 115
15.5 Design of biological filters 116
Chapter 16 - Constructed wetlands 119
16.1 Background 119
16.2 Definitions 120
16.3 Hydrology of wetlands 121
16.4 Wetland chemistry 123
16.5 Wetland ecosystem mass balance 130
16.6 Macrophytes in wetlands 131
16.7 Physical and biochemical parameters 133
16.8 Examples for natural and constructed wetlands 134
Chapter 17 - Rotating biological contactors 139
17.1 Introduction 139
17.2 Principle of operation 139
17.3 Design and loading criteria 139
17.4 Principle elements 140
17.5 Operational problems 141
Chapter 18 - Activated sludge processes 143
18.1 Background 143
18.2 Activated sludge process 143
18.3 Comparison between the activated sludge process, percolating filtration and wetland system 146
18.4 Activated sludge process types 147
18.5 Activated sludge process designs and kinetics 151
18.6 Summary of activated sludge processes 155
Chapter 19 - Iron and manganese removal 159
19.1 Introduction 159
19.2 Problems with iron and manganese 159
19.3 Basic removal processes 159
19.4 Advanced removal processes 160
Chapter 20 - Water softening 163
20.1 Introduction 163
20.2 Chemistry of water softening 163
20.3 Lime-soda softening 165
20.4 Lime softening 165
20.5 Excess lime softening 166
20.6 Lime recovery 166
Chapter 21 - Water microbiology 169
21.1 Statistics for applied microbiology 169
21.2 Protozoa 170
21.3 Biological effects of organic pollutants 173
21.4 Eutrophication and water treatment 175
21.5 Protozoology of treatment processes 176
21.6 Odour and toxins of natural origin 177
21.7 Public health aspects 177
Chapter 22 - Disinfection 183
22.1 Destroying pathogens and requirements of a disinfectant 183
22.2 Traditional methods of disinfection 184
22.3 Ozone 185
22.4 Chlorine dioxide 185
22.5 Chlorine as a disinfectant 186
22.6 Kinetics of chlorination 188
22.7 Applications of chlorine 188
22.8 Technology of chlorine addition 189
22.9 Advantages and disadvantages of chlorine 190
Chapter 23 - Sludge treatment and disposal 191
23.1 Introduction 191
23.2 Characteristics of wastewater sludges 191
23.3 Characterisation of wastewater sludges 192
23.4 Volume of sludge 194
23.5 Tests for dewatering of sludges 194
23.6 Sludge treatment and disposal objectives and methods 194
23.7 Treatment processes 196
23.8 Thickening and dewatering of sludges 197
23.9 Partial disposal 199
23.10 Land dumping and passive treatment 201
Chapter 24 - Wetlands treating contaminated stream water 203
24.1 Summary 203
24.2 Introduction 203
24.3 Materials and methods 204
24.4 Results and Discussion 209
24.5 Conclusions 220
Chapter 25 - Wetland systems to control roof runoff 223
25.1 Summary 223
25.2 Introduction 223
25.3 Methods 225
25.4 Results and discussion 229
25.5 Conclusions 237
Chapter 26 - Wetlands treating road runoff 239
26.1 Case study summary 239
26.2 Introduction 239
26.3 Site, materials and methodology 241
26.4 Experimental results and discussion 246
26.5 Conclusions and further work 253
Chapter 27 - Combined wetland and below-ground detention systems 255
27.1 Experimental case study summary 255
27.2 Introduction 255
27.3 Materials and methods 257
27.4 Results and discussion 260
27.5 Conclusions and further research 263
Chapter 28 - Modeling of constructed wetland performance 265
28.1 Summary 265
28.2 Introduction 265
28.3 Methodology and software 268
28.4 Results and discussion 273
28.5 Conclusions 282
Chapter 29 - Infiltration wetland systems 285
29.1 Summary 285
29.2 Introduction 285
29.3 Methods 286
29.4 Results and discussion 289
29.5 Conclusions 294
Chapter 30 - Sustainable urban drainage system model 297
30.1 Summary 297
30.2 Introduction 297
30.3 Sites, methodology and modeling 304
30.4 Results and discussion 314
30.5 Conclusions 318
Chapter 31 - Natural wetlands treating diffuse pollution 319
31.1 Case study overview 319
31.2 Introduction 320
31.3 Materials and methods 322
31.4 Results 327
31.5 Discussion 334
31.6 Conclusions 339
References 343
Index 355