Flocculation in Natural and Engineered Environmental Systems

Flocculation In Natural And Engineered Environmental Systems......Page 1
Preface......Page 4
Acknowledgments......Page 6
About The Editors......Page 7
Contributors......Page 11
Contents......Page 14
1.1 Introduction......Page 17
1.1.1 Floc Size......Page 18
1.1.2 Sample Handling And Stabilization.......Page 20
1.2 Floc Settling Velocity......Page 21
1.3 Floc Density And Porosity......Page 23
1.3.1 Floc Structure: Correlative Microscopy......Page 25
1.3.2 Extracellular Polymeric Substances......Page 26
1.4 Surface Charge And Hydrophobicity......Page 27
1.5 Microbial Ecology......Page 29
References......Page 30
I Freshwater Environments......Page 39
2.1 Introduction......Page 41
2.2 Definition Of Freshwater Flocs......Page 42
2.3 Types Of Freshwater Flocs......Page 45
2.4 Growth And Stability Of Freshwater Flocs......Page 50
2.5 Relevant Information From Microflocs......Page 51
2.6.1 Architecture In Relation To Floc Activities, Properties, And Behavior......Page 52
2.6.2 Relevant Findings For Floc Architecture From The Biofilm Literature......Page 54
2.7 Applicable New Technologies......Page 55
References......Page 56
Contents......Page 63
3.1 Introduction......Page 64
3.2 The Study Sites......Page 65
3.3 Methodology......Page 67
3.4.1 The Degree Of Aggregation Of Suspended Sediment In The Study Area......Page 68
3.4.2 Short-term Variability In The Epsd......Page 70
3.4.3 Intra-storm Variability In The Epsd And Associated Doa.......Page 71
3.4.4 Inter-storm And Seasonal Variability In The Epsd And Associated Doa.......Page 76
3.4.5 Effective Particle Density......Page 81
3.5 Sources Of Aggregated Sediment In The Exe Basin......Page 82
3.6 Conclusion......Page 83
References......Page 84
4.1 Introduction......Page 87
4.2.1 Study Area......Page 89
4.2.3 Suspended Sediment Measurements......Page 90
4.2.4 Settling Chamber Measurements......Page 93
4.2.6 Visual Characterization Of Aggregate Particles......Page 94
4.3 Results......Page 95
4.4 Discussion......Page 102
4.4.1 Fractal Concerns......Page 105
4.5 Conclusions......Page 106
References......Page 107
5.1 Introduction......Page 111
5.2.1 Fractal Aggregate Properties......Page 113
5.2.2 Model Development......Page 115
5.2.2.1 Conceptual Fractal Model Of Aggregation......Page 117
5.3.1 Image Analysis......Page 119
5.3.2 Materials And General Procedures......Page 121
5.3.2.2 Experiment Set 2......Page 122
5.3.2.3 Experiment Set 3......Page 123
5.4.1.1 Coagulation–flocculation......Page 125
5.4.1.2 Particlesizeand Shape......Page 126
5.4.1.4 Collision Frequency Function......Page 129
5.4.1.5 Settling Velocity......Page 132
5.5 Conclusions And Recommendations......Page 133
Nomenclature......Page 134
References......Page 135
Contents......Page 137
6.1 Introduction......Page 138
6.2.1 Handling Flocs For Microscopic Examination......Page 139
6.2.3 Clsm And 2p-lsm......Page 140
6.2.3.2 2p-lsm Limitations......Page 141
6.2.4 Synchrotron Radiation (soft X-ray Imaging)......Page 142
6.3.1.1 General Probes......Page 143
6.3.1.2 Lectins......Page 144
6.3.3 Nucleic Acids......Page 147
6.3.4 Charge/ Hydrophobicity......Page 148
6.4 Examination Of Eps Bound And Associated Molecules......Page 149
6.5 Digital Image Analyses......Page 150
6.5.1 Quantitative......Page 151
6.7 3d Rendering......Page 152
References......Page 153
7.1 Introduction......Page 159
7.2 Characterization Of The Major Aquatic Colloids......Page 160
7.2.1 Inorganic Colloids......Page 161
7.2.2 Allochthonous Macromolecules: Humic Substances......Page 164
7.2.3 Autochthonous Macromolecules: Proteins, Lipids, And Polysaccharides......Page 165
7.3 Principal Mechanisms Of Colloidal Stabilization And Destabilization......Page 166
7.3.2 Bridging Flocculation......Page 168
7.3.3 Depletion Flocculation......Page 169
7.4.1 Homocoagulation......Page 170
7.4.2 Heterocoagulation: Role Of Hs......Page 172
7.4.3 Heterocoagulation: Role Of Rigid Polysaccharides And Peptidoglycans......Page 173
7.4.4 Heterocoagulation: Contributions Of Other Types Of Organic Matter......Page 175
7.5 Summary And Future Perspectives......Page 178
References......Page 180
8.1 Introduction......Page 187
8.2 The Stormwater Detention System......Page 188
8.3.1 Rotating Circular Flume......Page 189
8.3.2 Deposition Tests......Page 190
8.4 Mathematical Model......Page 192
8.5.1.2 Turbulentdiffusion Coef.cient, D......Page 194
8.5.1.7 Model For The Growth-limiting Effect Of Turbulence......Page 195
8.6 Comparision Of Model Predictions With The Measured Data......Page 196
8.7 Summary And Conclusions......Page 201
Nomenclature......Page 202
References......Page 203
II Saltwater Environments......Page 205
9.1 Introduction......Page 207
9.2 The Structure And Properties Of Fibrils......Page 212
9.3 Mechanisms And Models Of Colloidal Aggregation And Scavenging......Page 214
9.4.1 How Does The Presence Of Metals Affect The Properties Of Fibrils?......Page 216
9.4.3 What Role Do Nanoscale Fibrils Play In Determining The Structure Of Larger Scale Aggregates?......Page 217
References......Page 219
10.1 Introduction......Page 227
10.2 Site Description......Page 229
10.3 Methods......Page 231
10.4 Results......Page 236
10.5 Discussion......Page 245
References......Page 248
11.1 Introduction......Page 253
11.2 Formation Of Organic Rich Aggregates......Page 254
11.3 The Descent Through The Water Column......Page 255
11.4 Transport Within The Benthic Boundary Layer: The Resuspension Loop......Page 257
11.5.1 Bacteria......Page 259
11.5.2 Fauna......Page 260
11.6 Conclusions......Page 261
References......Page 262
12.1 Introduction......Page 265
12.2 A Lagrangian Flocculation Model......Page 268
12.3 Floc Size Distribution Over The Water Depth......Page 272
12.4 Floc Size Distribution Over The Tidal Cycle......Page 276
12.5 Sediment Concentrations In Fluid Mud Layers......Page 281
12.6 Discussion And Conclusions......Page 284
References......Page 285
13.1 Introduction......Page 287
13.2.2 Particle Collision Rates......Page 289
13.3.1.1 Phytoplankton And The Critical Concentration......Page 292
13.3.1.2 Coagulation In A Stirred Container......Page 294
13.3.1.3 Steady-state Size Spectra......Page 295
13.3.2.1 Critical Concentration......Page 296
13.3.2.2 Estimating Stickiness......Page 297
13.3.3.1 Simple Algal Growth......Page 298
13.3.3.2 Plankton Food Web Model......Page 300
13.4 Discussion......Page 303
References......Page 304
III Engineered Systems......Page 309
14.1 Introduction......Page 311
14.2 Microbial Flocs In Wastewater Treatment......Page 312
14.3.1 Forms Of Phosphorus In Wastewater......Page 313
14.4 Quantifying Extracellular Enzyme Activity Associated With Microbial Flocs......Page 314
14.5 Measurement Of Phosphatase Activity In Activated Sludge Using Fluorogenic Substrates......Page 316
14.6 Localizing Extracellular Enzyme Activity Associated With Microbial Flocs......Page 319
14.7 Identification Of Populations Of Cells Responsible For Extracellular Po4ase Activities Within Floc- Associated Microbial Communities......Page 323
14.8 Conclusions......Page 327
References......Page 328
15.1 Introduction......Page 333
15.2.1 Phylogenetic Analysis Of 16s Ribosomal Rna Gene Sequences......Page 334
15.2.2 Fluorescence In Situ Hybridization......Page 335
15.2.3 Quantification And 3d Visualization Of Microorganisms By Confocal Laser Scanning Microscopy And Digital Image Analysis......Page 337
15.2.4 Methods To Determine Ecological Functions Of Uncultured Bacteria......Page 340
15.3 Discovery And Investigation Of Nitrospira-like Bacteria In Wastewater Treatment Plants......Page 344
15.4 Outlook......Page 347
References......Page 348
16.1 Introduction......Page 355
16.3.1 Bacterial Topography......Page 357
16.3.2 Surface Roughness......Page 360
16.3.3 Interaction Forces......Page 361
References......Page 364
Contents......Page 367
17.1.1 Definition Of Terms......Page 368
17.1.3 Why Should Biomass Deflocculation Under Transient Conditions Be Studied?......Page 369
17.2.1 Carbon Substrate Transients......Page 370
17.2.2 Periodic Substrate Oscillations......Page 372
17.2.3.2 Toxicity And Ph Transients......Page 373
17.2.3.3 Temperature Transients......Page 374
17.3.1 Transients Leading  To Biomass Deflocculation......Page 378
17.3.2 Mechanisms Of Biomass Deflocculation......Page 379
17.4.1 Sludge Floc Responses To The Temperature Shifts......Page 383
17.4.2 Proposed Mechanisms Of Sludge Deflocculation......Page 388
17.5 Summary And Future Perspectives......Page 390
References......Page 392
18.1 Introduction......Page 401
18.2.1 Dose– Response Curves......Page 403
18.2.2 Mathematical Models For Uv Disinfection......Page 404
18.3.1 The Role Of Floc Size......Page 406
18.3.2 The Role Of Floc Composition......Page 408
References......Page 410
19.1 Introduction......Page 413
19.2.4 Effluent Suspended Solids......Page 414
19.4 Results And Discussion......Page 415
Acknowledgments......Page 417
References......Page 418
IV Summary......Page 421
Contents......Page 423
20.1 Introduction......Page 424
20.2.1 Common Or Different Issues And Principles......Page 425
20.2.1.3 Modeling Within The Smoluchowski Framework......Page 426
20.2.1.5 Hindered Settling......Page 427
20.2.1.9 Floc Stability......Page 428
20.2.2 Common......Page 429
20.2.2.3 Density And Porosity......Page 430
20.2.2.6 Stickiness......Page 431
20.2.2.8 Surface Properties......Page 432
20.2.3 Field......Page 433
20.2.4 Latitude For Linkage Of Freshwater, Saltwater, And
engineering Principles, Methods, And Analysis......Page 434
20.2.5 Emerging Issues And Challenges......Page 435
20.3 Conclusion......Page 436
Acknowledgments......Page 437