with gas or oil US$ · m−3or kg−1fuel cp = proportionality constant between stirred and diluted sludge volume index – Cr = unit volume construction costs of the aeration tank US$ · m−3 Cr
Trang 2Handbook of
Biological Wastewater Treatment
Trang 4Handbook of
Biological Wastewater Treatment
Design and Optimisation of Activated Sludge Systems
Second Edition
A.C van Haandel and
J.G.M van der Lubbe
www.wastewaterhandbook.com
Trang 5The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for errors or omissions that may be made.
Disclaimer
The information provided and the opinions given in this publication are not necessarily those of IWA and should not be acted upon without independent consideration and professional advice IWA and the Author will not accept responsibility for any loss or damage suffered by any person acting or refraining from acting upon any material contained in this publication.
British Library Cataloguing in Publication Data
A CIP catalogue record for this book is available from the British Library
ISBN 9781780400006 (Hardback)
ISBN 9781780400808 (eBook)
Trang 6Preface xv
Notes on the second edition xvii
About the authors xxi
Acknowledgements xxiii
Symbols, parameters and abbreviations xxv
Chapter 1 Scope of text 1
1.0 Introduction 1
1.1 Advances in secondary wastewater treatment 2
1.2 Tertiary wastewater treatment 3
1.3 Temperature influence on activated sludge design 5
1.4 Objective of the text 6
Chapter 2 Organic material and bacterial metabolism 9
2.0 Introduction 9
2.1 Measurement of organic material 9
2.1.1 The COD test 10
2.1.2 The BOD test 12
2.1.3 The TOC test 15
2.2 Comparison of measurement parameters 16
Trang 72.3 Metabolism 17
2.3.1 Oxidative metabolism 18
2.3.2 Anoxic respiration 20
2.3.3 Anaerobic digestion 22
Chapter 3 Organic material removal 25
3.0 Introduction 25
3.1 Organic material and activated sludge composition 26
3.1.1 Organic material fractions in wastewater 26
3.1.2 Activated sludge composition 27
3.1.2.1 Active sludge 29
3.1.2.2 Inactive sludge 29
3.1.2.3 Inorganic sludge 29
3.1.2.4 Definition of sludge fractions 30
3.1.3 Mass balance of the organic material 31
3.2 Model notation 36
3.3 Steady-state model of the activated sludge system 38
3.3.1 Model development 38
3.3.1.1 Definition of sludge age 39
3.3.1.2 COD fraction discharged with the effluent 40
3.3.1.3 COD fraction in the excess sludge 40
3.3.1.4 COD fraction oxidised for respiration 44
3.3.1.5 Model summary and evaluation 45
3.3.2 Model calibration 49
3.3.3 Model applications 53
3.3.3.1 Sludge mass and composition 53
3.3.3.2 Biological reactor volume 56
3.3.3.3 Excess sludge production and nutrient demand 58
3.3.3.4 Temperature effect 62
3.3.3.5 True yield versus apparent yield 63
3.3.3.6 F/M ratio 65
3.3.4 Selection and control of the sludge age 67
3.4 General model of the activated sludge system 70
3.4.1 Model development 73
3.4.2 Model calibration 76
3.4.3 Application of the general model 77
3.5 Configurations of the activated sludge system 78
3.5.1 Conventional activated sludge systems 78
3.5.2 Sequential batch systems 79
3.5.3 Carrousels 81
3.5.4 Aerated lagoons 82
Trang 8Chapter 4
Aeration 85
4.0 Introduction 85
4.1 Aeration theory 88
4.1.1 Factors affecting klaand DOs 89
4.1.2 Effect of local pressure on DOs 89
4.1.3 Effect of temperature on klaand DOs 91
4.1.4 Oxygen transfer efficiency for surface aerators 92
4.1.5 Power requirement for diffused aeration 94
4.2 Methods to determine the oxygen transfer efficiency 97
4.2.1 Determination of the standard oxygen transfer efficiency 97
4.2.2 Determination of the actual oxygen transfer efficiency 99
Chapter 5 Nitrogen removal 107
5.0 Introduction 107
5.1 Fundamentals of nitrogen removal 108
5.1.1 Forms and reactions of nitrogenous matter 108
5.1.2 Mass balance of nitrogenous matter 110
5.1.3 Stoichiometrics of reactions with nitrogenous matter 115
5.1.3.1 Oxygen consumption 115
5.1.3.2 Effects on alkalinity 117
5.1.3.3 Effects on pH 120
5.2 Nitrification 123
5.2.1 Nitrification kinetics 124
5.2.2 Nitrification in systems with non aerated zones 134
5.2.3 Nitrification potential and nitrification capacity 136
5.2.4 Design procedure for nitrification 137
5.3 Denitrification 141
5.3.1 System configurations for denitrification 142
5.3.1.1 Denitrification with an external carbon source 142
5.3.1.2 Denitrification with an internal carbon source 143
5.3.2 Denitrification kinetics 146
5.3.2.1 Sludge production in anoxic/aerobic systems 146
5.3.2.2 Denitrification rates 147
5.3.2.3 Minimum anoxic mass fraction in the pre-D reactor 149
5.3.3 Denitrification capacity 151
5.3.3.1 Denitrification capacity in a pre-D reactor 151
5.3.3.2 Denitrification capacity in a post-D reactor 153
5.3.4 Available nitrate 156
5.4 Designing and optimising nitrogen removal 158
5.4.1 Calculation of nitrogen removal capacity 160
5.4.2 Optimised design of nitrogen removal 165
5.4.2.1 Complete nitrogen removal 166
5.4.2.2 Incomplete nitrogen removal 169
Trang 95.4.2.3 Effect of recirculation of oxygen on denitrification capacity 172
5.4.2.4 Design procedure for optimized nitrogen removal 177
Chapter 6 Innovative systems for nitrogen removal 181
6.0 Introduction 181
6.1 Nitrogen removal over nitrite 183
6.1.1 Basic principles of nitritation 184
6.1.2 Kinetics of high rate ammonium oxidation 187
6.1.3 Reactor configuration and operation 188
6.1.4 Required model enhancements 189
6.2 Anaerobic ammonium oxidation 190
6.2.1 Anammox process characteristics 191
6.2.2 Reactor design and configuration 193
6.3 Combination of nitritation with anammox 195
6.3.1 Two stage configuration (nitritation reactor–Anammox) 195
6.3.2 Case study: full scale SHARON - Anammox treatment 198
6.3.3 Single reactor configurations 199
6.4 Bioaugmentation 203
6.5 Side stream nitrogen removal: evaluation and potential 204
Chapter 7 Phosphorus removal 207
7.0 Introduction 207
7.1 Biological Phosphorus Removal 208
7.1.1 Mechanisms involved in biological phosphorus removal 208
7.1.2 Bio-P removal system configurations 212
7.1.3 Model of biological phosphorus removal 214
7.1.3.1 Enhanced cultures 214
7.1.3.2 Mixed cultures 220
7.1.3.3 Denitrification of bio-P organisms 225
7.1.3.4 Discharge of organic phosphorus with the effluent 228
7.2 Optimisation of biological nutrient removal 229
7.2.1 Influence of wastewater characteristics 229
7.2.2 Improving substrate availability for nutrient removal 231
7.2.3 Optimisation of operational conditions 233
7.2.4 Resolving operational problems 238
7.3 Chemical phosphorus removal 239
7.3.1 Stoichiometrics of chemical phosphorus removal 239
7.3.1.1 Addition of metal salts 239
7.3.1.2 Addition of lime 241
7.3.1.3 Effects on pH 242
7.3.2 Chemical phosphorus removal configurations 243
7.3.2.1 Pre-precipitation 245
7.3.2.2 Simultaneous precipitation 247
Trang 107.3.2.3 Post-precipitation 252
7.3.2.4 Sidestream precipitation 253
7.3.3 Design procedure for chemical phosphorus removal 255
Chapter 8 Sludge settling 259
8.0 Introduction 259
8.1 Methods to determine sludge settleability 260
8.1.1 Zone settling rate test 260
8.1.2 Alternative parameters for sludge settleability 263
8.1.3 Relationships between different settleability parameters 264
8.2 Model for settling in a continuous settler 266
8.2.1 Determination of the limiting concentration Xl 270
8.2.2 Determination of the critical concentration Xc 270
8.2.3 Determination of the minimum concentration Xm 271
8.3 Design of final settlers 274
8.3.1 Optimised design procedure for final settlers 274
8.3.2 Determination of the critical recirculation rate 278
8.3.3 Graphical optimization of final settler operation 281
8.3.4 Optimisation of the system of biological reactor and final settler 283
8.3.5 Validation of the optimised settler design procedure 286
8.3.5.1 US EPA design guidelines 286
8.3.5.2 WRC and modified WRC design guidelines 286
8.3.5.3 STORA/STOWA design guidelines 287
8.3.5.4 ATV design guidelines 287
8.3.5.5 Solids flux compared with other design methods 288
8.4 Physical design aspects for final settlers 291
8.5 Final settlers under variable loading conditions 293
Chapter 9 Sludge bulking and scum formation 297
9.0 Introduction 297
9.1 Microbial aspects of sludge bulking 297
9.2 Causes and control of sludge bulking 301
9.2.1 Sludge bulking due to a low reactor substrate concentration 301
9.2.2 Guidelines for selector design 303
9.2.3 Control of bulking sludge in anoxic-aerobic systems 305
9.2.4 Other causes of sludge bulking 309
9.3 Non-specific measures to control sludge bulking 310
9.4 Causes and control of scum formation 315
Chapter 10 Membrane bioreactors 319
10.0 Introduction 319
10.1 Membrane bioreactors (MBR) 320
Trang 1110.2 MBR configurations 322
10.2.1 Submerged MBR 324
10.2.2 Cross-flow MBR 325
10.2.3 Comparison of submerged and cross-flow MBR 331
10.3 MBR design considerations 335
10.3.1 Theoretical concepts in membrane filtration 335
10.3.2 Impact on activated sludge system design 338
10.3.3 Pre-treatment 344
10.3.4 Module configuration– submerged MBR 345
10.3.5 Module aeration– submerged MBR 346
10.3.6 Key design data of different membrane types 347
10.4 MBR operation 347
10.4.1 Operation of submerged membranes 347
10.4.2 Operation of cross-flow membranes 348
10.4.3 Membrane fouling 348
10.4.4 Membrane cleaning 349
10.5 MBR technology: evaluation and potential 352
Chapter 11 Moving bed biofilm reactors 355
11.0 Introduction 355
11.1 MBBR technology and reactor configuration 357
11.1.1 Carriers used in MBBR processes 359
11.1.2 Aeration system 360
11.1.3 Sieves and mixers 361
11.2 Features of MBBR process 362
11.3 MBBR process configurations 364
11.3.1 Pure MBBR 364
11.3.2 MBBR as pre-treatment 365
11.3.3 MBBR as post-treatment 366
11.3.4 Integrated fixed film reactors 367
11.4 Pure MBBR design and performance 367
11.4.1 Secondary treatment of municipal sewage 367
11.4.2 Secondary treatment of industrial wastewater 371
11.4.3 Nitrification 372
11.4.4 Nitrogen removal 374
11.4.5 Phosphorus removal 377
11.5 Upgrading of existing activated sludge plants 378
11.5.1 High rate pre-treatment MBBR for BOD/COD removal 378
11.5.2 Upgrading of secondary CAS to nitrification 379
11.5.3 Nitrification in IFAS processes 381
11.5.4 IFAS for nitrogen removal 384
11.6 Solids removal from MBBR effluent 384
11.6.1 Gravity settling 384
Trang 1211.6.2 Micro-sand ballasted lamella sedimentation 385
11.6.3 Dissolved air flotation 386
11.6.4 Micro screening 386
11.6.5 Media filtration 390
11.6.6 Membrane filtration 390
Chapter 12 Sludge treatment and disposal 391
12.0 Introduction 391
12.1 Excess sludge quality and quantity 392
12.2 Sludge thickeners 395
12.2.1 Design of sludge thickeners using the solids flux theory 395
12.2.2 Design of sludge thickeners using empirical relationships 399
12.3 Aerobic digestion 403
12.3.1 Kinetic model for aerobic sludge digestion 403
12.3.1.1 Variation of the volatile sludge concentration 404
12.3.1.2 Variation of the oxygen uptake rate 405
12.3.1.3 Variation of the nitrate concentration 406
12.3.1.4 Variation of the alkalinity 406
12.3.1.5 Variation of the BOD 409
12.3.2 Aerobic digestion in the main activated sludge process 410
12.3.3 Aerobic digester design 413
12.3.4 Optimisation of aerobic sludge digestion 419
12.3.5 Operational parameters of the aerobic digester 423
12.4 Anaerobic digestion 430
12.4.1 Stoichiometry of anaerobic digestion 432
12.4.2 Configurations used for anaerobic digestion 435
12.4.3 Influence of operational parameters 438
12.4.4 Performance of the high rate anaerobic digester 442
12.4.4.1 Removal efficiency of volatile suspended solids 442
12.4.4.2 Biogas production 443
12.4.4.3 Energy generation in anaerobic sludge digesters 444
12.4.4.4 Solids destruction and stabilised excess sludge production 445
12.4.4.5 Nutrient balance in the anaerobic digester 446
12.4.5 Design and optimisation of anaerobic digesters 451
12.5 Stabilised sludge drying and disposal 454
12.5.1 Natural sludge drying 455
12.5.2 Design and optimisation of natural sludge drying beds 459
12.5.2.1 Determination of the percolation time (t2) 459
12.5.2.2 Determination of the evaporation time (t4) 460
12.5.2.3 Influence of rain on sludge drying bed productivity 468
12.5.3 Accelerated sludge drying with external energy 469
12.5.3.1 Use of solar energy 470
12.5.3.2 Use of combustion heat from biogas 473
Trang 13Chapter 13
Anaerobic pretreatment 477
13.0 Introduction 477
13.1 Anaerobic treatment of municipal sewage 478
13.1.1 Configurations for anaerobic sewage treatment 480
13.1.1.1 Anaerobic filter 480
13.1.1.2 Fluidised and expanded bed systems 481
13.1.1.3 Upflow anaerobic sludge blanket (UASB) reactor 482
13.1.1.4 The RALF system 484
13.1.2 Evaluation of different anaerobic configurations 484
13.2 Factors affecting municipal UASB performance 486
13.2.1 Design and engineering issues 487
13.2.2 Operational- and maintenance issues 495
13.2.3 Inappropriate expectations of UASB performance 496
13.2.4 Presence of sulphate in municipal sewage 497
13.2.5 Energy production and greenhouse gas emissions 501
13.2.5.1 Carbon footprint 501
13.2.5.2 Biogas utilization 506
13.3 Design model for anaerobic sewage treatment 516
13.3.1 Sludge age as the key design parameter 516
13.3.2 Influence of the temperature 521
13.3.3 Characterisation of anaerobic biomass 522
13.4 UASB reactor design guidelines 528
13.5 Post-treatment of anaerobic effluent 538
13.5.1 Secondary treatment of anaerobic effluent 539
13.5.1.1 Applicability of the ideal steady state model for COD removal 542
13.5.1.2 Stabilisation of aerobic excess sludge in the UASB reactor 553
13.5.2 Nitrogen removal from anaerobic effluent 559
13.5.2.1 Bypass of raw sewage to the activated sludge system 560
13.5.2.2 Anaerobic digestion with reduced methanogenic efficiency 562
13.5.2.3 Application of innovative nitrogen removal configurations 564
13.5.3 Future developments 566
13.5.3.1 Two stage anaerobic digestion 566
13.5.3.2 Psychrophilic anaerobic wastewater treatment 567
13.6 Anaerobic treatment of industrial wastewater 568
Chapter 14 Integrated cost-based design and operation 575
14.0 Introduction 575
14.1 Preparations for system design 576
14.1.1 The basis of design 577
14.1.1.1 Wastewater characteristics 577
14.1.1.2 Kinetic parameters and settleability of the sludge 582
14.1.2 Costing data 582
14.1.2.1 Investment costs 583
Trang 1414.1.2.2 Operational costs 586
14.1.2.3 Annualised investment costs 588
14.1.3 Performance objectives 589
14.1.4 Applicable system configurations 591
14.1.5 Limitations and constraints 592
14.2 Optimised design procedure 595
14.2.1 System A1: Conventional secondary treatment 595
14.2.2 System A2: Secondary treatment with primary settling 607
14.2.3 System B1: Combined anaerobic-aerobic treatment 610
14.2.4 System C1: Nitrogen removal 621
14.2.5 System C2: Nitrogen and phosphorus removal 627
14.2.6 System comparison 633
14.3 Factors influencing design 635
14.3.1 Influence of the wastewater temperature 635
14.3.2 Influence of the sludge age 636
14.4 Operational optimisation 638
14.4.1 Comparison of different operational regimes 638
14.4.2 Optimised operation of existing treatment plants 642
14.5 Integrated design examples 644
14.5.1 Nutrient removal in different configurations 644
14.5.2 Membrane bioreactor design– case study 657
14.6 Final Remarks 668
Reference list 671
Appendix 1 Determination of the oxygen uptake rate 685
A1.1 Determination of the apparent OUR 686
A1.2 Correction factors of the apparent OUR 687
A1.2.1 Representativeness of mixed liquor operational conditions 687
A1.2.2 Critical dissolved oxygen concentration 687
A1.2.3 Hydraulic effects 688
A1.2.4 Absorption of atmospheric oxygen 689
A1.2.5 The relaxation effect 692
Appendix 2 Calibration of the general model 695
A2.1 Calibration with cyclic loading 696
A2.2 Calibration with batch loading 700
Appendix 3 The non-ideal activated sludge system 703
Appendix 4 Determination of nitrification kinetics 709
Trang 15Appendix 5
Determination of denitrification kinetics 717
Appendix 6 Extensions to the ideal model 723
A6.1 Imperfect solid-liquid separation in final settler 723
A6.1.1 Particulate organic nitrogen and phosphorus in the effluent 724
A6.1.2 Excess sludge production and composition 726
A6.2 Nitrifier fraction in the volatile sludge mass 727
Appendix 7 Empiric methods for final settler sizing 731
A7.1 Stora design guidelines (1981) 731
A7.1.1 Theoretical aspects 731
A7.1.2 Application of the STORA 1981 design guidelines 734
A7.1.3 Modifications to the STORA 1981 design guidelines 736
A7.2 Final settler design comparison methodology 738
A7.3 ATV design guidelines (1976) 741
A7.3.1 Theoretical aspects 741
A7.3.2 Modifications to the ATV 1976 design guidelines 744
Appendix 8 Denitrification in the final settler 747
Appendix 9 Aerobic granulated sludge 754
A9.1 Benefits of aerobic granular sludge systems 757
A9.2 System design and operation 761
A9.2.1 Process configurations 761
A9.2.2 Reactor configuration 764
A9.2.3 Operation of AGS systems 764
A9.2.4 Start-up of aerobic granular sludge reactors 767
A9.3 Granular biomass: evaluation and potential 767
Trang 16In this book the authors seek to present the state-of-the-art theory concerning the various aspects of theactivated sludge system and to develop procedures for optimized cost based design- and operation Thebook has been written for students at MSc or PhD level, as well as for engineers in consulting firms andenvironmental protection agencies
Since its conception almost a century ago, the activated sludge system evolved as the most popularconfiguration for wastewater treatment Originally this was due to its high efficiency at removingsuspended solids and organic material, which at that time was considered as the most importanttreatment objective
The earliest design principles for activated sludge systems date back to the second half of the 20thcentury, almost fifty years after the first systems were constructed and many further developments haveoccurred since As nitrogen is one of the key components in eutrophication of surface water, in the1970s nitrogen removal became a requirement and this resulted in the incorporation of nitrification- anddenitrification processes in the activated sludge system An important subsequent development was theintroduction of chemical- and biological phosphorus removal in the 1980s and 1990s
Over the last decades the predominance of the activated sludge system has been consolidated,
as cost-efficient and reliable biological removal of suspended solids, organic material and themacro-nutrients nitrogen and phosphorus has consistently been demonstrated This versatility is alsoshown in the continuous development of new configurations and treatment concepts, such asanaerobic pre-treatment, membrane bioreactors, granular aerobic sludge and innovative systems fornitrogen removal It is therefore scarcely surprising that many books have been dedicated to thesubject of wastewater treatment and more specifically to one or more aspects of the activated sludgesystem So why should you consider buying this particular book? The two main reasons why thisbook is an invaluable resource for everybody working in the field of wastewater treatment are thefollowing:
– The scope of this book is extremely broad and deep, as not only the design of the activated sludgesystem, but also that of auxiliary units such as primary and final settlers, pre-treatment units, sludgethickeners and digesters is extensively discussed;
Trang 17– The book offers a truly integrated design method, which can be easily implemented in spreadsheets andthus may be adapted to the particular needs of the user.
In this text, the theory related to the different processes taking place in activated sludge systems is presented
It is demonstrated that the sludge age is the main design parameter for both aerobic and anaerobic systems Asteady-state model is developed that will prove extremely useful for the design and optimisation of activatedsludge systems This model describes the removal of organic material in the activated sludge system and itsconsequences for the principal parameters determining process performance: effluent quality, excess sludgeproduction and oxygen consumption
The design guidelines for biological and chemical nutrient removal are integrated with those of othermain treatment units, such as final settlers, primary settlers and anaerobic pre-treatment units, sludgethickeners and -digesters Finally, the text will also deal with operational issues: for example sludgesettling and -bulking, oxygen transfer, maintenance of an adequate pH, sludge digestion and methaneproduction
Visit us at our website www.wastewaterhandbook.com for more information, the latest updates and freeExcel design tools, or contact us at info@wastewaterhandbook.com
Trang 18Notes on the second edition
This significantly revised and updated second edition expands upon our earlier work Valuable feedbackwas received from the wastewater treatment courses, based on this handbook, given in the period 2007
to 2011 This welcome feedback has been incorporated in the book in order to improve the didacticqualities Where needed the book structure was adapted to make it more intuitively understandable bythe reader, while many additional examples have been introduced to clarify the text Finally, obsoletetext has been removed and a number of obvious errors corrected The main additions/changes withregards to the book contents are:
First of all, a new section has been written that explains the model notation used in this book in much moredetail Additional examples facilitate the readers understanding about the way the steady state model forCOD removal is constructed and how it can be used The difference between true and apparent yield isexplained, while also the section on the F/M ratio, and especially the reasons not to use it, has beenexpanded
The section on aeration, previously part of Chapter 3, has been updated and moved to a separate Chapter
The effect of the oxygen recycle to the anoxic zones on the denitrification capacity is now explicitly included
in the model Furthermore, the concept of available nitrate, i.e the flux of nitrate to the pre-D and post-Dzones is explained in more detail The design procedure for nitrification has been elaborated and severalextensive examples for optimized design of nitrogen removal have been added
Trang 19Chapter 6 – Innovative systems for nitrogen removal
As the developments on the subject of innovative nitrogen removal are so rapid, this section has beensignificantly rewritten and expanded and now merits it own chapter
Several examples on the design of chemical phosphorus removal systems have been added
To explain the theory better, several examples have been added The section on sludge thickening wasexpanded with an alternative empirical design approach and has been moved to Chapter 12 – SludgeTreatment and Disposal
The section on sludge separation problems has been rewritten and expanded to include the latest theories andexperimental findings on the development and prevention of both sludge bulking- and scum formation
The chapter on new system configurations is now devoted to MBR only, as the section on aerobic granulatedsludge has been updated based on the return of experience from full-scale installations and is moved toAppendix A9 Several new examples detail the design of both cross-flow and submerged membraneconfigurations
A new chapter about a technology that has become popular due to its compactness and its potential forupgrading of existing activated sludge systems
The chapter is expanded with a section on sludge thickening: both the solids flux design method and anempirical design approach are presented
This part has been completely rewritten based on the experiences obtained from an extensive review of largefull-scale UASB based sewage treatment plants The main design and operational issues in UASB treatmentare discussed, while new sections have been introduced on the subject of the loss of methane with theeffluent, the impact on greenhouse gas emissions and the problems related to the presence of sulphate inthe raw sewage
The anaerobic design model has been expanded to include the presence of sulphate in the influent and that
of suspended solids in the effluent A new section has been introduced that deals with the methodology ofUASB reactor design The section on combined anaerobic-aerobic treatment has been adapted to reflect thelatest findings on the extent of nitrogen removal possible after anaerobic pre-treatment Some interestingnew treatment configurations are presented, combining anaerobic pre-treatment with innovative nitrogen
Trang 20removal Finally a thoroughly updated section on industrial anaerobic reactors has been included, based onthe authors experiences within Biothane Systems International.
The section on cost calculation now contains several examples of the calculation of investment-, operationaland annualized costs Furthermore the chapter is expanded with two extensive integrated design examples:(I) combined nitrogen and phosphorus removal in which bio-P removal is compared with pre- andsimultaneous precipitation and (II) MBR in which the system configurations for submerged andcross-flow membranes are evaluated
List of model parameters
Complementary to the section on model notation, a comprehensive list of all parameters used throughout thebook has been compiled and added for easy reference
New appendices
– Appendix A5 - determination of denitrification kinetics
– Appendix A7 - empiric methods for final settler sizing
– Appendix A8 - denitrification in the final settler
– Appendix A9 - aerobic granulated sludge
Trang 22About the authors
Adrianus van Haandel (1948) holds an MSc degree from the Technical University of Eindhoven – TheNetherlands and a PhD from the University of Cape Town – South Africa He has worked at theUniversity of Campina Grande in Brazil since 1971, where he coordinates research on biologicalwastewater treatment He has extensive experience as an independent consultant and is involved with anumber of international expert committees Together with other authors he has written several booksabout different aspects of wastewater treatment including“Anaerobic sewage treatment in regions with ahot climate” and “Advanced biological treatment processes for industrial wastewaters: principles andapplications” Adrianus can be contacted at prosab@uol.com.br
Jeroen van der Lubbe (1971) is a senior process & product development engineer at Biothane SystemsInternational, part of Veolia Water – Solutions and Technologies Apart from process design andconsultancy, he has been responsible for the development of the UpthaneTM– Veolia’s municipal UASBsolution while currently he is product development manager of the anaerobic MBR– MemthaneTM
andinvolved in the first European implementation He graduated in 1995 at the Environmental Department
of the Wageningen University – The Netherlands and since then has been involved extensively in thedesign, engineering and operation of both industrial and municipal wastewater treatment plants Beforejoining Biothane, he worked at Fontes & Haandel Engenharia Ambiental, Raytheon Engineers &Constructors, DHV Water and Tebodin Consultants and Engineers Jeroen can be contacted atinfo@wastewaterhandbook.com
Trang 24This book reflects the experience of the authors with different aspect of biological wastewater treatment.Insofar as the theory of biological processes is concerned, it has very much been influenced by the ideasdeveloped by the research group lead by Professor Gerrit Marais at the University of Cape Town –South Africa Another important input was the ongoing cooperative research program at severalBrazilian universities, PROSAB, financed by the federal government through its agency FINEP Theexperimental results generated by this group and the discussions, especially with Professors Pedro Alemand Marcos von Sperling, constituted important contributions
In the Netherlands, the following persons are acknowledged for their input: Merle de Kreuk at theTechnical University Delft and Tom Peeters from DHV BV– for their input to and review of the section
on aerobic granular sludge, Wouter van der Star at the Technical University Delft and Tim Hülsen ofPaques BV – for their review of the section on innovative nitrogen removal, Darren Lawrence at KochMembrane Systems and Hans Ramaekers at Triqua BV– for their contribution to the section on MBRtechnology, Hallvard Ødegaard, professor emeritus at the Department of Hydraulic and EnvironmentalEngineering of the Norwegian University of Science and Technology in Trondheim, for his extensiveinput to the chapter on MBBR, Sybren Gerbens at the Friesland Water Authority – for his input onconstruction and treatment costs while he also provided several photos used in this book, André vanBentem at DHV BV and Joost de Haan at the Delfland Water Board who supplied many interestingphotos and finally Barry Heffernan for licensing photos and proofreading
Finally a special word of thanks to the author’s wives, Paula Frassinetti and Lotje van de Poll, for theirunfailing support during the long incubation period in which this book….and the second edition was written.Not to mention the time it took to develop the course material…
Trang 26Symbols, parameters and abbreviations
In this book a naming convention is used in which (I) the number of characters required to identify a uniqueparameter is minimized and (II) the description of the parameter can be deducted in a logical way from itsindividual constituents Thus in general a parameter is constructed from a combination of one or more mainidentifiers (either in capital- or in normal font) followed by one or more subscripts (capital- or normal font).The main identifiers indicate the class of the parameter, such as daily applied load or production (M),substrate (S), solids (X) or constants (K), while the subscripts specify the type involved, such as (v)=volatile, (t)=total, et cetera Thus for example MStiis defined as the total (t) daily applied mass (M) oforganic material (S) in the influent (i) In most cases a specific letter can therefore have more than onemeaning However, it should be easy to deduct what it refers to from the context where it is used Assuch the amount of characters required to uniquely identify a specific parameter is reduced to the minimum
In the remainder of this section the list of abbreviations and the list of symbols and parameters arepresented The latter contains in alphabetical order all of the parameters used in the second edition of theHandbook, including a short description and the unit of measure Subsequently, after a number of keyparameters have been introduced in the main text, the model notation used in this book will be explained
in much more detail in Section 3.2
LIST OF ABBREVIATIONS
AIC = annualized investment costs
Anammox = anaerobic (anoxic) ammonium oxidation
Trang 27BAS = biofilm activated sludge system
CANON = completely autotrophic nitrogen removal over nitrite
CAS = conventional activated sludge system
CSTR = completely stirred tank reactor (completely mixed reactor)
DSVI = diluted sludge volume index
EGSB = expanded granular sludge bed
EPA = environmental protection agency
GSBR = granulated sludge bed reactor
HUSB = hydrolysis upflow sludge blanket
IFAS = integrated fixed film activated sludge system
LPCF = low pressure cross-flow
MBBR = moving bed biofilm reactor
OLAND = oxygen limited autrotrophic nitrification – denitrification
PAO = phosphate accumulating organisms
SBR = sequencing batch reactor
SHARON = single reactor for high activity ammonium removal over nitriteSSVI3.5 = stirred sludge volume index (determined at 3.5 g · l−1)
STORA = stichting toegepast onderzoek naar de reiniging van afvalwaterSTOWA = stichting toegepast onderzoek waterbeheer
TAC = total annualised costs
TIC = total investment costs
TKN = total Kjeldahl nitrogen
TOC = total operational costs
Trang 28TOC = total organic carbon
TSS = total suspended solids
UASB = upflow anaerobic sludge blanket
VFA = volatile fatty acids
VSS = volatile suspended solids
ZSV = zone settling velocity
LIST OF SYMBOLS AND PARAMETERS
a = mixed liquor recirculation factor
(from nitrification zone to pre-D zone)
(–)
Aa = total area occupied by apertures in a UASB reactor m2
Alk∞ = final alkalinity after complete decay of active sludge in
aerobic digester
mg CaCO3· l−1Alkd = alkalinity consumed in the aerobic digester mg CaCO3· l−1
Alki = initial alkalinity concentration (aerobic digestion) mg CaCO3· l−1
Alke = final alkalinity concentration (aerobic digestion) mg CaCO3· l−1
bh = decay rate for heterotrophic bacteria (non bio-P) d−1
bhT = decay rate for heterotrophic bacteria (non bio-P) at
temperature T
d−1
Trang 29Bn = mass balance recovery factor for nitrogenous material (–)
BODvss = BOD value of a unit of organic sludge (aerobic digestion) mg BOD · mg−1VSS
bv = apparent decay constant of heterotrophic bacteria (non bio-P) d−1
Cd = unit volume construction costs of final settler US$ · m−3
Cd1 = unit volume construction costs of the primary settler US$ · m−3
Cda = unit volume construction costs of aerobic digester US$ · m−3
Cdi = unit volume construction costs of anaerobic digester US$ · m−3
Cgen = unit construction cost of power generation US$ · kW−1
Ch = costs of heating (e.g with gas or oil) US$ · m−3or kg−1fuel
cp = proportionality constant between stirred and diluted
sludge volume index
(–)
Cr = unit volume construction costs of the aeration tank US$ · m−3
Cr = specific active biomass production per unit mass daily applied
biodegradable COD
mg VSS · d · mg−1COD
Crh = specific active biomass production of heterotrophic organisms
per unit mass daily applied biodegradable COD
mg VSS · d · mg−1COD
Crn = specific active nitrifiers production of per unit mass of daily
applied nitrifiable nitrogen
mg VSS · d · mg−1N
Crp = specific active biomass production of bio-P organisms
per unit mass daily applied biodegradable COD
mg VSS · d · mg−1COD
Cth = unit volume construction costs of a sludge thickener US$ · m−3
Cu = unit volume construction costs of a UASB reactor US$ · m−3
Dc1p = denitrification capacity from utilization of slowly
Dc3 = denitrification capacity in post-D zone mg N · l−1influent
Dcd = denitrification capacity in the final settler mg N · l−1influent
Trang 30DOav = average oxygen concentration during OUR test mg O2· l−1
DOm = oxygen concentration measured by oxygen sensor mg O2· l−1
DOmt = oxygen concentration in the membrane tank mg O2· l−1
DOs = saturation concentration of dissolved oxygen
−1
DOs20 = saturation concentration of dissolved oxygen at 20°C mg O2· l−1
DOsa = saturation concentration of dissolved oxygen
under actual conditions
f = fraction of the influent flow discharged to the
first reactor in step feed systems
(–)
fa(N-1) = active sludge fraction in the sludge entering the Nth
digester mg VSS · mg−1VSS
fac = fraction of construction costs required for construction
of additional (non-specified) units
mg VSS · mg−1VSS
fae = active sludge concentration in aerobic digester mg VSS · mg−1VSS
fai = initial active sludge concentration (aerobic digestion) mg VSS · mg−1VSS
faN = active sludge fraction in the sludge leaving the Nth
aerobicdigester
mg VSS · mg−1VSS
fav1 = active fraction of organic sludge from primary settling mg VSS · mg−1VSS
fav2 = active fraction of organic sludge from activated sludge system mg VSS · mg−1VSS
fave = active fraction of organic stabilised sludge mg VSS · mg−1VSS
fbh = fraction of Sbiconsumed by normal heterotrophic biomass mg COD · mg−1COD
fbp = fraction of Sbisequestered by bio-P organisms mg COD · mg−1COD
fbp = slowly biodegradable (particulate) COD fraction
in the raw wastewater
mg COD · mg−1COD
Trang 31f′bp = slowly biodegradable (particulate) COD fraction
in the pre-settled wastewater
fbsh = fraction of Sbsiconsumed by normal heterotrophic bacteria mg COD · mg−1COD
fbsp = fraction of Sbsisequestered by bio-P organisms mg COD · mg−1COD
fbsu = biodegradable soluble fraction of organic COD in anaerobic
fdn = denitrification constant = (1 - fcv·Y)/2.86 (–)
fh2s = inorganic H2S-COD in UASB effluent expressed as fraction
of influent COD
mg COD · mg−1COD
fh2su = inorganic H2S-COD fraction in anaerobic effluent mg COD · mg−1COD
fi = additional investment costs (non-construction related) (–)
fm = maximum anoxic sludge fraction allowed for
selected sludge age (when Nae= Nad)
m3· m−3
fm = activity coefficient for a monovalent ion in the mixed liquor (–)
fmin = minimum required anoxic sludge mass fraction kg TSS · kg−1TSS
f′np = inert particulate COD fraction after primary settling mg COD · mg−1COD
fnpu = inert particulate fraction of COD in anaerobic effluent mg COD · mg−1COD
f′ns = inert soluble COD fraction after primary settling mg COD · mg−1COD
fns = non biodegradable, soluble influent COD fraction mg COD · mg−1COD
fnsu = non biodegradable, soluble COD fraction in anaerobic effluent mg COD · mg−1COD
fpd = fraction of bio-P organisms capable of denitrification (–)
fpp = maximum poly-P fraction of bio-P organisms mg P · mg−1VSS
Trang 32fpu = putrescible fraction of anaerobic sludge mg VSS · mg−1VSS
fr = average frequency of exposure at the chlorine injection point d−1
f′sb = fraction of biodegradable COD that is easily biodegradable
remaining after primary settling
mg COD · mg−1BCOD
fsb = fraction of biodegradable COD that is easily biodegradable mg COD · mg−1BCOD
fv = organic sludge fraction = ratio between volatile and
total sludge concentration
mg VSS · mg−1TSS
fve = organic sludge fraction in stabilised sludge mg VSS · mg−1TSS
fvp = organic sludge fraction of bio-P organisms mg VSS · mg−1TSS
fxd = sludge mass fraction located in final settler kg TSS · kg−1TSS
fxvd = fraction of final settler volume filled with sludge m3· m−3
h = liquid height above base of V-notch or above perforation m
H2 = thickener clarification zone / sludge storage zone (ATV) m
H3 = thickener compression zone / separation zone (ATV) m
H4 = thickener sludge removal zone / clear water zone (ATV) m
Trang 33I = investment costs US$
K1 = rate constant for denitrification on easily
biodegradable organic material
mg N · g−1Xa-VSS · d−1
k1* = “real” equilibrium constant for CO2dissociation,
corrected for ionic activity
mol · l−1
K2 = rate constant for denitrification on slowly
biodegradable organic material
mg N · g−1Xa-VSS · d−1
k2 = equilibrium constant for bicarbonate dissociation mol · l−1
k2* = “real” equilibrium constant of the bicarbonate dissociation,
corrected for ionic activity
mol · l−1
K3 = rate constant for denitrification due to endogenous respiration mg N · g−1Xa-VSS · d−1
klaa = oxygen transfer coefficient under actual conditions h−1
Kmp = specific utilisation rate of slowly bio-degradable (adsorbed)
Ko = half saturation constant for aerobic processes mg O2· l−1
Ksp = saturation constant (Monod) for growth on slowly
biodegradable, adsorbed substrate
mg COD · mg−1Xa
Kss = saturation constant (Monod) for growth on easily
biodegradable substrate
mg COD · l−1
kw = equilibrium constant for the dissociation of water mol2· l−2
kw* = “real” equilibrium constant for the dissociation of water,
corrected for ionic activity
mol2· l−2
Trang 34Le = height of water layer remaining at end of drying period mm
Li = height of initial water layer applied to sludge bed mm
mciv = maintenance costs for civil part of plant % of TIC per year
MCrd = construction costs of aeration tank and final settler US$
MCthdi = total construction costs of thickener and anaerobic digester US$
MEchem = total chemical excess sludge production kg TSS · d−1
MEmeoh = chemical excess sludge production (metal oxides) kg TSS · d−1
MEmep = chemical excess sludge production (metal phosphates) kg TSS · d−1
mEt = specific excess sludge production
(equal to apparent yield Yap)
mg TSS · mg−1COD
mEt2 = specific secondary excess sludge production mg TSS · mg−1COD
mEte = specific stabilised excess sludge production mg TSS · mg−1COD
mEtu = specific anaerobic excess sludge production mg TSS · mg−1COD
MEtx = total (secondary) excess sludge production corrected for loss
of suspended solids in the effluent
kg TSS · d−1
mEv = specific organic sludge production (apparent yield Yap) mg VSS · mg−1COD
MEv = volatile or organic excess sludge production kg VSS · d−1
MEv2 = organic secondary excess sludge production kg VSS · d−1
mEve = specific stabilised organic excess sludge production mg VSS · mg−1COD
MEve = stabilised organic excess sludge production kg VSS · d−1
MEvu = organic anaerobic excess sludge production kg VSS · d−1
mExvna = specific inactive excess sludge production mg VSS · mg−1COD
Trang 35mme&i = maintenance costs for mechanical, electrical and
instrumentation part of plant
% of TIC
MNav1 = mass of nitrate available in (i.e returned to) the pre-D zone kg N · d−1
MNd1 = mass of nitrate denitrified in the pre-D reactor kg N · d−1
MNd3 = mass of nitrate denitrified in the post-D reactor kg N · d−1
MNdd = mass of nitrate denitrified in the final settler kg N · d−1
MNdp = denitrification due to consumption of slowly
mNl = specific nitrogen discharge with the excess sludge mg N · mg−1COD
MNl = nitrogen removal with produced excess sludge kg N · d−1
mNle = specific nitrogen removal due to discharge with the stabilised
excess sludge
mg N · mg−1COD
MNle = mass of nitrogen removed with stabilised excess sludge kg N · d−1
MNlx = mass of nitrogen removed with the excess sludge corrected for
the loss of organic nitrogen with the effluent
kg N · d−1
MOc = oxygen demand for COD oxidation (= MSo) kg O2· d−1
MOeq = equivalent oxygen demand
(recovered oxygen from denitrification)
kg O2· d−1
MPchem = mass of phosphorus removed by chemical precipitation kg P · d−1
MPl = phosphorus removal with excess sludge production kg P · d−1
mPl = specific phosphorus discharge with the excess sludge mg P · mg−1COD
MPl1 = mass of phosphorus removed with the primary excess sludge kg P · d−1
mPle = specific phosphorus removal due to discharge with the
stabilised excess sludge
mg P · mg−1COD
MPle = mass of phosphorus removed with stabilised excess sludge kg P · d−1
MPlex2 = mass of phosphorus removed with the secondary
excess sludge, corrected for the loss of organic nitrogen
with the effluent
kg P · d−1
MPlx = mass of phosphorus removed with the excess sludge,
corrected for loss of organic phosphorus in the effluent
kg P · d−1
Trang 36MPte = phosphorus load in the effluent kg P · d−1
mq2 = specific secondary excess sludge flow rate m3· kg−1COD
mSbu = fraction of total COD present as biodegradable COD
in UASB effluent
mg COD · mg−1COD
MSda = COD mass digested in UASB and emitted to atmosphere kg COD · d−1
mSe = fraction of influent COD leaving the system with
the effluent (soluble COD only)
mg COD · mg−1COD
mSeu = fraction of influent COD ending up as non-settleable
COD in the UASB effluent
mg COD · mg−1COD
MSo = mass of COD oxidized in the system (= MOc) kg COD · d−1
mSod = fraction of influent COD oxidized in aerobic digester mg COD · mg−1COD
MSseq = mass of COD sequestered by bio-P organisms kg COD · d−1
mSte = fraction of influent COD leaving the system with
the effluent (includes particulate COD)
mg COD · mg−1COD
MSxv = mass of COD discharged from the system in the
excess sludge
kg COD · d−1
mSxv = fraction of influent COD discharged from the system
in the excess sludge
mg COD · mg−1COD
mSxv1 = fraction of influent COD leaving the system in the
primary excess sludge
kg COD · d−1
mSxv2 = fraction of influent COD discharged from the system
in the secondary excess sludge
kg COD · d−1
mSxve = fraction of influent COD leaving the system with stabilised
excess sludge
mg COD · mg−1COD
MSxve = mass of COD discharged from the system in
the stabilised excess sludge
kg COD · d−1
mSxvu = influent COD fraction converted into anaerobic
excess sludge
mg COD · mg−1COD
Trang 37MSxvu = COD mass discharged as anaerobic excess sludge
from the UASB
kg COD · d−1
mXa = active sludge mass per unit mass daily applied COD mg VSS · d · mg−1COD
MXah = total active heterotrophic sludge mass in system kg VSS
MXan = total active nitrifier sludge mass in system kg VSS
MXap = total mass of active bio-P organisms in system kg VSS
mXau = active anaerobic sludge mass per unit mass daily applied COD mg VSS · d · mg−1COD
MXau = total active anaerobic sludge mass in system kg VSS
mXbpu = non-degraded biodegradable sludge mass per unit mass daily
applied COD
mg VSS · d · mg−1COD
MXbpu = total mass of non-degraded biodegradable
sludge mass in system
kg VSS
mXe = endogenous sludge mass per unit mass daily applied COD mg VSS · mg−1COD · d−1
MXen = total mass of endogenous nitrifier sludge in system kg VSS
MXep = total mass of endogenous bio-P sludge in system kg VSS
mXeu = endogenous anaerobic sludge mass per unit mass
daily applied COD
mg VSS · d · mg−1COD
mXi = inert sludge mass per unit mass daily applied COD mg VSS · d · mg−1COD
mXiu = non-biodegradable particulate anaerobic sludge mass
per unit mass daily applied COD
mg VSS · d · mg−1COD
MXiu = total mass of non-biodegradable particulate anaerobic
sludge in system
kg VSS
mXmu = inorganic anaerobic sludge mass per unit mass
daily applied COD
mg ISS · d · mg−1COD
MXmu = total mass of inorganic anaerobic sludge in system kg VSS
mXt = total sludge mass per unit mass daily applied COD mg TSS · d · mg−1COD
MXtba = available sludge mass storage capacity in final settler kg TSS
MXtbr = required sludge mass storage capacity in final settler kg TSS
mX = anaerobic sludge mass per unit mass daily applied COD mg TSS · mg−1COD · d−1
Trang 38MXtu = total mas of anaerobic sludge in system kg TSS
mXv = volatile sludge mass per unit mass daily applied COD mg VSS · mg−1COD · d−1
MXvh = total organic heterotrophic biomass in system kg VSS
mXvu = anaerobic organic sludge per unit mass daily applied COD mg VSS · mg−1COD · d−1
MXvu = total anaerobic organic sludge mass in system kg VSS
Nad = desired/required effluent ammonium concentration mg N · l−1
Nc = nitrification capacity (= nitrified ammonium concentration) mg N · l−1influent
Nc/Sbi = ratio between nitrification capacity and biodegradable
influent COD
mg N/mg COD
(Nc/Sbi)l = limiting ratio between nitrification capacity and biodegradable
influent COD for the Bardenpho process
mg N · mg−1COD
(Nc/Sbi)o = maximum ratio between nitrification capacity and
biodegradable influent COD allowing full nitrogen removal
mg N · mg−1COD
Ndd = concentration of nitrate that will be denitrified in the return
sludge stream per passage through the final settler
mg N · l−1
Nddmax = maximum allowable production of nitrogen gas in the return
sludge flow during its passage through the final settler to the
Nl = nitrogen concentration removed with the excess sludge mg N · l−1influent
Nld = nitrogen concentration released in digester mg N · l−1influent
Nle = nitrogen concentration removed with the stabilised
Trang 39Nln = nitrogen concentration removed with the nitrifier
excess sludge
mg N · l−1influent
Nlx = nitrogen concentration discharged with excess sludge
(corrected for loss of organic nitrogen in the effluent)
mg N · l−1influent
NN2eq = equilibrium dissolved nitrogen gas concentration at the
maximum liquid depth of the final settler, assuming an
atmosphere of 100% nitrogen
mg N · l−1
NN2in = dissolved nitrogen gas concentration in the incoming
mixed liquor flow
mg N · l−1
Nn∞ = nitrate concentration when decay of active sludge is complete
(aerobic digestion)
mg N · l−1
Nnd = nitrate production in the aerobic digester mg N · l−1
Nni = initial nitrate concentration (aerobic digestion) mg N · l−1
Np = nitrification potential (= maximum ammonium concentration
that can be nitrified)
mg N · l−1influent
Nte,max = maximum nitrogen effluent concentration
(all released nitrogen recycled to aeration tank)
mg N · l−1
Nte,min = minimum nitrogen effluent concentration
(no recycle of released nitrogen to aeration tank)
mg N · l−1
(Nti/Sti)l = limiting ratio between influent TKN and total influent COD for
the applicability of the Bardenpho process
mg N · mg−1COD
(Nti/Sti)o = maximum ratio between influent TKN and total influent COD
allowing full nitrogen removal
mg N · mg−1COD
Oc = oxygen uptake rate (respiration) for COD oxidation mg O2· l−1· d−1
Oeq = oxygen recovery rate (equivalent oxygen uptake rate)
due to denitrification
mg O2· l−1· d−1
Oex,sbp = exogenous respiration rate due to consumption of slowly
biodegradable (adsorbed) substrate
mg O2· l−1· d−1
Oex,sbs = exogenous respiration rate due to consumption of easily
biodegradable substrate
mg O2· l−1· d−1
Trang 40On = oxygen uptake rate for nitrification mg O2· l−1· d−1
OT4,5 = oxygen transfer efficiency at 4.5 m submergence %
Otd = total oxygen uptake rate (aerobic digester) mg O2· l−1· d−1
OURabs = rate of change of oxygen concentration in reactor
due to hydraulic effects
mg O2· l−1· h−1
OURh = rate of change of oxygen concentration in reactor
due to adsorption of atmospheric oxygen
mg O2· l−1· h−1OURm = maximum oxygen uptake rate due to nitrification mg O2· l−1· h−1
Pchem = concentration of phosphorus to be chemically removed mg P · l−1influent
PEres = residual pollution load in wastewater after treatment US$ · PE−1
Pl = influent phosphorus concentration removed
with the excess sludge
mg P · l−1influent
Pld = influent phosphorus concentration in digested sludge
(i · e · released to liquid phase)
mg P · l−1influent
Ple = influent phosphorus concentration removed with
the stabilised excess sludge
mg P · l−1influent
Plx = phosphorus concentration discharged with excess sludge
(corrected for loss of organic phosphorus with the effluent)
mg P · l−1influent
Pmin = minimum required energy required to keep sludge in suspension W · m−3
Pope = particulate organic phosphorus in effluent mg P · l−1