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Book Details
Abstract
Coagulation and Flocculation in Water and Wastewater Treatment provides a comprehensive account of coagulation and flocculation techniques and technologies in a single volume covering theoretical principles to practical applications.
Thoroughly revised and updated this new edition has been progressively modified and increased in scope to cater for the requirements of practitioners involved with water and wastewater treatment.
New topics in this new edition include :
• activated sludge bulking and foaming control and enhanced bioflocculation;
• algae removal and harvesting;
• dissolved organic nitrogen (DON) removal;
• inorganics removal;
• turbidity and its measurement;
• wastewater treatment by coagulation and chemically enhanced primary treatment (CEPT).
The book presents the subject logically and sequentially from theoretical principles to practical applications. Successive chapters deal with, in turn, properties of materials present in waters and wastewaters; characteristics and types of coagulants commonly in use; mechanisms and practical implications of destabilization of waterborne material using metal coagulants and polyelectrolytes; considerations and requirements for coagulant addition at the rapid mixing stage; theoretical and practical considerations of flocculation; and details of experimental procedures for assessing primary coagulants, flocculant aids, sludge conditioners, and flocculation parameters. Numerous examples are included as appropriate.
Treatment and disposal of sludges resulting from coagulation-flocculation related operations is dealt with in an Appendix. This important topic has been separated from the main text to avoid disturbing the continuum of the presentation.
Coagulation and Flocculation in Water and Wastewater Treatment is a readable and useful resource for the water scientist and engineer. It is a convenient reference handbook providing numerous examples and appended information and it is a vital text for course material for undergraduate and postgraduate students.
Table of Contents
| Section Title | Page | Action | Price |
|---|---|---|---|
| Cover | Cover | ||
| Contents | v | ||
| Preface | xi | ||
| Chapter 1: Introduction | 1 | ||
| 1.1 GENERAL | 1 | ||
| 1.2 STABILITY AND DESTABILIZATION | 2 | ||
| 1.3 DEFINITIONS | 5 | ||
| 1.4 PERFORMANCE CRITERIA | 7 | ||
| 1.5 SUMMARY | 7 | ||
| 1.6 REFERENCES | 8 | ||
| Chapter 2: Colloids and interfaces | 9 | ||
| 2.1 INTRODUCTION | 9 | ||
| 2.2 ORIGIN OF SURFACE CHARGE | 13 | ||
| 2.3 EFFECT OF SURFACE CHARGE | 14 | ||
| 2.4 ADSORPTION | 14 | ||
| 2.5 INNER PART OF ELECTRICAL DOUBLE LAYER | 17 | ||
| 2.6 DIFFUSE PART OF ELECTRICAL DOUBLE LAYER | 20 | ||
| 2.6.1 Assumptions | 20 | ||
| 2.6.2 Distribution of potential with distance from the charged surface | 21 | ||
| 2.6.3 Thickness of double layer | 23 | ||
| 2.6.4 Effect of ionic strength on double layer | 25 | ||
| 2.6.5 Effect of nature of counter ions | 26 | ||
| 2.7 STERN’S MODEL OF COMPLETE DOUBLE LAYER | 26 | ||
| 2.8 COLLOID STABILITY IN TERMS OF THE DOUBLE LAYER | 27 | ||
| 2.8.1 Energy of interaction between particles | 27 | ||
| 2.8.2 Theoretical optimal concentration of electrolyte required for destabilization | 30 | ||
| 2.8.3 Schulze-Hardy rule | 31 | ||
| 2.9 ELECTROKINETIC MEASUREMENTS | 31 | ||
| 2.10 REFERENCES | 32 | ||
| Chapter 3: Coagulants | 33 | ||
| 3.1 INTRODUCTION | 33 | ||
| 3.2 METAL COAGULANTS | 33 | ||
| 3.2.1 Commonly used metal coagulants | 33 | ||
| 3.2.1.1 Aluminum sulfate | 34 | ||
| 3.2.1.2 Acidified aluminum sulfate (Acid alum) | 35 | ||
| 3.2.1.3 Aluminum chloride | 35 | ||
| 3.2.1.4 Sodium aluminate | 36 | ||
| 3.2.1.5 Ferric sulfate | 37 | ||
| 3.2.1.6 Ferrous sulfate | 37 | ||
| 3.2.1.7 Chlorinated ferrous sulfate | 38 | ||
| 3.2.1.8 Ferric chloride | 38 | ||
| 3.2.1.9 Prepolymerized aluminum and iron coagulants | 39 | ||
| 3.2.1.9.1 Aluminum chlorohydrate | 40 | ||
| 3.2.1.9.2 Polyaluminum chloride | 41 | ||
| 3.2.1.9.3 Polyaluminum silicate sulfate and polyaluminum silicate chloride | 41 | ||
| 3.2.1.9.4 Polymerized ferric and blended aluminum-ferric coagulants | 41 | ||
| 3.2.1.9.5 Handling of pre-polymerized coagulants | 42 | ||
| 3.2.1.10 Preparation and feeding of coagulant products | 42 | ||
| 3.2.1.11 Contamination of commercial chemicals | 44 | ||
| Chapter 4: Treatment with metal coagulants | 81 | ||
| 4.1 INTRODUCTION | 81 | ||
| 4.2 DESTABILIZATION OF HYDROPHOBIC COLLOIDS | 84 | ||
| 4.2.1 Extent of hydrolysis and adsorption | 84 | ||
| 4.2.2 Effect of coagulant dosage | 84 | ||
| 4.2.3 Effect of colloid concentration | 87 | ||
| 4.2.4 Effect of pH | 90 | ||
| 4.2.4.1 General | 90 | ||
| 4.2.4.2 pH 1.0 | 90 | ||
| 4.2.4.3 pH 2.0 | 91 | ||
| 4.2.4.4 pH 3.0 to 5.0 | 91 | ||
| 4.2.4.5 pH 6.0 to 9.0 | 92 | ||
| 4.2.4.6 Further considerations | 92 | ||
| 4.3 DESTABILIZATION OF HYDROPHILIC COLLOIDS | 97 | ||
| 4.4 REMOVAL OF NATURAL ORGANIC MATTER | 97 | ||
| 4.4.1 Organic color | 97 | ||
| 4.4.1.1 Nature of organic color | 97 | ||
| 4.4.1.2 Classification of organic color | 98 | ||
| 4.4.1.3 Disadvantages of organic color in water supplies | 99 | ||
| 4.4.1.4 Measurement of color | 100 | ||
| 4.4.1.5 Destabilization of organic color with metal coagulants | 103 | ||
| 4.4.2 Enhanced coagulation | 109 | ||
| 4.4.2.1 Effectiveness of metal coagulants | 113 | ||
| 4.4.2.2 Mechanisms of NOM removal with metal coagulants | 116 | ||
| 4.4.2.3 Predictive models for enhanced coagulation | 117 | ||
| 4.4.2.4 Importance of jar tests | 121 | ||
| 4.4.2.5 Impacts of enhanced coagulation | 123 | ||
| 4.5 ALGAE REMOVAL AND HARVESTING | 125 | ||
| 4.6 PATHOGEN REMOVAL | 133 | ||
| 4.6.1 Removal of Giardia and Cryptosporidium | 133 | ||
| 4.6.2 Virus removal | 134 | ||
| 4.7 EFFECT OF ANIONS | 135 | ||
| 4.7.1 General | 135 | ||
| 4.7.2 Effect of sulfate | 136 | ||
| 4.7.3 Effect of phosphate | 138 | ||
| 4.8 CHEMICAL PHOSPHORUS REMOVAL IN WASTEWATER TREATMENT | 139 | ||
| 4.8.1 General | 139 | ||
| 4.8.2 Mechanisms of chemical phosphorus removal | 144 | ||
| 4.8.2.1 Simultaneous phosphorus precipitation | 157 | ||
| 4.8.2.2 Sequential phosphorus precipitation | 159 | ||
| 4.8.3 Applications of chemical phosphorus removal | 161 | ||
| 4.8.3.1 Alternative methods of phosphorus precipitation | 176 | ||
| 4.9 DISSOLVED ORGANIC NITROGEN (DON) REMOVAL IN WASTEWATER TREATMENT | 179 | ||
| 4.9.1 General | 179 | ||
| 4.9.2 Characteristics of effluent DON | 180 | ||
| 4.9.3 Impacts of effluent DON | 182 | ||
| 4.9.4 Measurement of DON | 184 | ||
| 4.9.5 Strategies for DON removal | 184 | ||
| 4.9.5.1 Enhanced coagulation | 184 | ||
| 4.9.5.2 Impacts of DON removal on phosphorus and other constituents | 187 | ||
| 4.9.5.3 Solid-liquid separation technology | 189 | ||
| 4.9.5.4 Other approaches for DON removal | 189 | ||
| 4.10 WASTEWATER TREATMENT BY COAGULATION AND CHEMICALLY ENHANCED PRIMARY TREATMENT, CEPT | 190 | ||
| 4.10.1 Dependence of CEPT removals on wastewater characteristics | 191 | ||
| 4.10.2 Case studies of CEPT | 193 | ||
| 4.10.3 Parameters for CEPT control | 199 | ||
| 4.10.4 Degree of flocculation required for CEPT | 199 | ||
| 4.11 ACTIVATED SLUDGE BULKING AND FOAMING CONTROL AND ENHANCED BIOFLOCCULATION | 201 | ||
| 4.12 INORGANICS REMOVAL | 204 | ||
| 4.12.1 Arsenic removal | 204 | ||
| 4.12.2 Copper removal | 208 | ||
| 4.12.3 Fluoride removal | 210 | ||
| 4.12.4 Manganese removal | 212 | ||
| 4.13 STAGED COAGULATION AND SEQUENCING | 219 | ||
| 4.14 EFFECTS OF PREOZONATION | 223 | ||
| 4.15 EFFECTS OF TEMPERATURE | 224 | ||
| 4.16 RESIDUAL ALUMINUM | 227 | ||
| 4.17 REFERENCES | 230 | ||
| Chapter 5: Treatment with polymers | 247 | ||
| 5.1 INTRODUCTION | 247 | ||
| 5.2 MECHANISMS OF DESTABILIZATION | 248 | ||
| 5.2.1 General | 248 | ||
| 5.2.2 The bridging mechanism | 249 | ||
| 5.2.2.1 Dispersion in the suspension | 249 | ||
| 5.2.2.2 Adsorption at the solid-liquid interface | 250 | ||
| 5.2.2.3 Compression of adsorbed chains | 251 | ||
| 5.2.2.4 Bridge formation | 252 | ||
| 5.2.3 The electrostatic patch mechanism | 253 | ||
| 5.3 POLYELECTROLYTES AS PRIMARY COAGULANTS | 258 | ||
| 5.3.1 General | 258 | ||
| 5.3.2 Turbidity removal using polyelectrolytes | 258 | ||
| 5.3.3 Organics removal using polyelectrolytes | 262 | ||
| 5.3.4 Algae removal and harvesting using polyelectrolytes | 266 | ||
| 5.3.5 Pathogen removal using polyelectrolytes | 269 | ||
| 5.3.6 Wastewater treatment by coagulation with polyelectrolytes and CEPT | 270 | ||
| 5.3.7 Activated sludge bulking and foaming control and enhanced bioflocculation | 273 | ||
| 5.4 POLYELECTROLYTES AS FLOCCULANT AIDS | 277 | ||
| 5.4.1 Polymers as filter aids | 281 | ||
| 5.5 POLYMERS AS SLUDGE CONDITIONERS | 282 | ||
| 5.6 REFERENCES | 286 | ||
| Chapter 6: Rapid mixing | 293 | ||
| 6.1 INTRODUCTION | 293 | ||
| 6.2 REQUIREMENTS FOR RAPID MIXING DEVICES | 294 | ||
| 6.2.1 General | 294 | ||
| 6.2.2 Comparison of back-mix and plug-flow reactors | 296 | ||
| 6.2.3 Velocity gradient requirements | 299 | ||
| 6.2.4 Rapid mixer retention time | 300 | ||
| 6.2.5 Tapered rapid mix velocity gradient | 300 | ||
| 6.2.6 Coagulant feed concentration | 301 | ||
| 6.2.7 Sequence of chemical addition | 301 | ||
| 6.3 DESIGN OF RAPID MIXING DEVICES | 302 | ||
| 6.3.1 General | 302 | ||
| 6.3.2 Backmix reactors | 303 | ||
| 6.3.3 In-line mixers without controlled velocity gradient | 303 | ||
| 6.3.3.1 Pipe bend | 304 | ||
| 6.3.3.2 Sudden expansion within a pipe | 305 | ||
| 6.3.3.3 Orifice plate within a pipe | 305 | ||
| 6.3.3.4 Diffuser grids in channel | 306 | ||
| 6.3.3.5 Hydraulic jump in channel | 308 | ||
| 6.3.4 In-line mixers with controlled velocity gradient | 310 | ||
| 6.4 REFERENCES | 313 | ||
| Chapter 7: Flocculation | 315 | ||
| 7.1 INTRODUCTION | 315 | ||
| 7.2 PERIKINETIC FLOCCULATION | 317 | ||
| 7.3 ORTHOKINETIC FLOCCULATION | 318 | ||
| 7.3.1 Theoretical development | 318 | ||
| 7.3.2 Working equation | 324 | ||
| 7.3.3 Flocculation reactors in series | 325 | ||
| 7.3.4 Adequacy of G and GT as design parameters | 326 | ||
| 7.3.5 Experimental determination of flocculation parameters | 327 | ||
| 7.3.5.1 Inconstancy of KB | 328 | ||
| 7.4 DESIGN OF FLOCCULATION BASINS | 329 | ||
| 7.4.1 General | 329 | ||
| 7.4.2 Types of flocculation chambers and devices | 329 | ||
| 7.4.2.1 Baffled chambers | 330 | ||
| 7.4.2.2 Granular media beds | 332 | ||
| 7.4.2.3 Other hydraulic flocculators | 333 | ||
| 7.4.2.4 Diffused air | 334 | ||
| 7.4.2.5 Rotating blades | 335 | ||
| 7.4.2.6 Reciprocating blades | 343 | ||
| 7.4.2.7 Start-up of flocculation devices | 344 | ||
| 7.4.3 Short circuiting in flocculation reactors | 344 | ||
| 7.4.4 Compartmentalization | 345 | ||
| 7.4.5 Combined flocculation – sedimentation basins | 348 | ||
| 7.4.5.1 Solids contact blanket clarifiers | 349 | ||
| 7.4.6 Transfer of flocculated water | 352 | ||
| 7.5 REFERENCES | 353 | ||
| Chapter 8: Testing and control of coagulation and flocculation | 357 | ||
| 8.1 INTRODUCTION | 357 | ||
| 8.2 OPTIMIZING PRIMARY COAGULANT TYPE, DOSAGE AND PH | 358 | ||
| 8.2.1 General | 358 | ||
| 8.2.2 Apparatus | 359 | ||
| 8.2.3 Chemical solutions | 360 | ||
| 8.2.4 Criteria describing process performance | 362 | ||
| 8.2.5 Jar test procedure | 367 | ||
| 8.2.6 Analysis of results | 370 | ||
| 8.3 USING THE JAR TEST TO EVALUATE SETTLING | 372 | ||
| 8.4 EVALUATING FLOCCULANT AIDS | 374 | ||
| 8.4.1 General | 374 | ||
| 8.4.2 Initial choice of flocculant aid | 375 | ||
| 8.4.3 Preparation of polyelectrolyte solutions | 376 | ||
| 8.4.4 Experimental procedure | 377 | ||
| 8.5 EVALUATING SLUDGE CONDITIONERS | 379 | ||
| 8.5.1 General | 379 | ||
| 8.5.2 Experimental procedures | 380 | ||
| 8.6 OPTIMIZING FLOCCULATION PARAMETERS | 384 | ||
| 8.6.1 General | 384 | ||
| 8.6.2 Apparatus | 386 | ||
| 8.6.3 Experimental procedure | 388 | ||
| 8.6.4 Analysis of data | 392 | ||
| 8.7 CONTROL SYSTEMS FOR COAGULATION | 395 | ||
| 8.7.1 Introduction | 395 | ||
| 8.7.2 Electrokinetic measurements | 396 | ||
| 8.7.2.1 Electrophoresis measurements | 398 | ||
| 8.7.2.2 Streaming current measurements | 400 | ||
| 8.7.2.3 Colloid titration | 403 | ||
| 8.7.3 Monitoring floc formation | 405 | ||
| 8.7.4 Data driven control systems | 409 | ||
| 8.8 REFERENCES | 415 | ||
| Appendix A: Turbidity and its measurement | 421 | ||
| A.1 INTRODUCTION | 421 | ||
| A.2 THE ADVANTAGES OF TURBIDITY MEASUREMENTS | 422 | ||
| A.3 TURBIDITY AS SURROGATE FOR PARTICLE CONCENTRATIONS | 426 | ||
| A.4 PRINCIPLES OF TURBIDITY MEASUREMENT | 428 | ||
| A.5 TURBIDITY INSTRUMENTS | 429 | ||
| A.6 INSTRUMENT CALIBRATION | 435 | ||
| A.7 TECHNIQUES FOR ACCURATE TURBIDITY MEASUREMENTS | 437 | ||
| A.8 REFERENCES | 439 | ||
| Appendix B: Processing and disposal of coagulant sludges | 441 | ||
| B.1 INTRODUCTION | 441 | ||
| B.2 PRODUCTION OF WATER PLANT RESIDUALS | 444 | ||
| B.2.1 Estimating sludge quantities | 444 | ||
| B.2.2 Alternative coagulants and dosage reduction | 447 | ||
| B.2.3 Sludge characteristics | 448 | ||
| B.2.4 Sludge conditioning | 450 | ||
| B.2.4.1 Polymer conditioning | 450 | ||
| B.2.4.2 Freezing | 455 | ||
| B.2.4.3 Thermal conditioning | 458 | ||
| B.3 FILTER BACKWASH | 458 | ||
| B.4 SLUDGE LAGOONS | 462 | ||
| B.5 SLUDGE DRYING BEDS | 465 | ||
| B.6 MECHANICAL THICKENING AND DEWATERING | 469 | ||
| B.6.1 Sludge thickening | 471 | ||
| B.6.1.1 Gravity thickeners | 471 | ||
| B.6.1.2 Belt thickeners | 477 | ||
| B.6.1.3 Flotation thickeners | 477 | ||
| B.6.1.4 Centrifuge thickening | 478 | ||
| B.6.1.5 Other thickening devices | 478 | ||
| B.6.2 Sludge dewatering | 481 | ||
| B.6.2.1 Vacuum filters | 481 | ||
| B.6.2.2 Centrifuges | 482 | ||
| B.6.2.3 Belt filter press | 484 | ||
| B.6.2.4 Filter presses | 486 | ||
| B.6.2.5 Other dewatering devices | 489 | ||
| B.7 COAGULANT RECOVERY | 491 | ||
| B.8 SLUDGE DISPOSAL | 499 | ||
| B.8.1 Introduction | 499 | ||
| B.8.2 Disposal to municipal sewers | 501 | ||
| B.8.3 Land application of water plant sludge | 504 | ||
| B.9 REFERENCES | 506 | ||
| Index | 515 |