Biological Wastewater Treatment in Warm Climate Regions Marcos von Sperling and
Biological Wastewater Treatment in Warm Climate Regions Marcos von Sperling and Carlos Augusto de Lemos Chernicharo Department of Sanitary and Environmental Engineering Federal University of Minas Gerais, Brazil VOLUME ONE Published by IWA Publishing, Alliance House, 12 Caxton Street, London SW1H 0QS, UK Telephone: +44 (0) 20 7654 5500; Fax: +44 (0) 20 7654 5555; Email: [email protected] Website: www.iwapublishing.com First published 2005 Reprinted 2006 C 2005 IWA Publishing Copy-edited and typeset by TechBooks, India Printed by TJ International, Padstow, UK Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the UK Copyright, Designs and Patents Act (1998), no part of this publication may be reproduced, stored or transmitted in any form or by any means, without the prior permission in writing of the publisher, or, in the case of photographic reproduction, in accordance with the terms of licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licenses issued by the appropriate reproduction rights organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to IWA Publishing at the address printed above. The publisher makes no representation, expressed 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 or of the editors, and should not be acted upon without independent consideration and professional advice. IWA and the editors 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 Library of Congress Cataloguing-in-Publication Data A catalogue record for this book is available from the Library of Congress ISBN: 1 84339 002 7 (this volume and set) Contents Volume One Preface Dedication The authors List of authors by chapter xi xv xvii xix PART ONE INTRODUCTION TO WASTEWATER CHARACTERISTICS, TREATMENT AND DISPOSAL 1 Introduction to water quality and water pollution 1.1 Introduction 1.2 Uses of water 1.3 Water quality requirements 1.4 Water pollution 2 Wastewater characteristics 2.1 Wastewater flowrates 2.2 Wastewater composition 3 3 5 5 8 11 11 30 3 Impact of wastewater discharges to water bodies 3.1 Introduction 3.2 Pollution by organic matter and stream self purification 3.3 Contamination by pathogenic microorganisms 3.4 Eutrophication of lakes and reservoirs 3.5 Quality standards for wastewater discharges and waterbodies 79 79 79 125 133 152 4 Overview of wastewater treatment systems 4.1 Wastewater treatment levels 4.2 Wastewater treatment operations, processes and systems 4.3 Preliminary treatment 165 165 166 180 v vi Contents 4.4 4.5 4.6 4.7 Primary treatment Secondary treatment Removal of pathogenic organisms Analysis and selection of the wastewater treatment process 181 182 217 217 5 Overview of sludge treatment and disposal 5.1 Introduction 5.2 Relationships in sludge: solids levels, concentration and flow 5.3 Quantity of sludge generated in the wastewater treatment processes 5.4 Sludge treatment stages 5.5 Sludge thickening 5.6 Sludge stabilisation 5.7 Sludge dewatering 5.8 Sludge disinfection 5.9 Final disposal of the sludge 244 244 248 6 Complementary items in planning studies 6.1 Preliminary studies 6.2 Design horizon and staging periods 6.3 Preliminary design of the alternatives 6.4 Economical study of alternatives 279 279 281 283 283 251 254 257 258 260 270 274 PART TWO BASIC PRINCIPLES OF WASTEWATER TREATMENT 7 Microbiology and ecology of wastewater treatment 7.1 Introduction 7.2 Organisms present in water and wastewater 7.3 Biological cells 7.4 Energy and carbon sources for microbial cells 7.5 Metabolism of microorganisms 7.6 Energy generation in microbial cells 7.7 Ecology of biological wastewater treatment 297 297 298 299 280 301 302 306 8 Reaction kinetics and reactor hydraulics 8.1 Introduction 8.2 Reaction kinetics 8.3 Mass balance 8.4 Reactor hydraulics 319 319 320 327 330 9 Conversion processes of organic and inorganic matter 9.1 Characterisation of substrate and solids 9.2 Conversion processes of the carbonaceous and nitrogenous matters 9.3 Time progress of the biochemical oxidation of the carbonaceous matter 9.4 Principles of bacterial growth 9.5 Modelling of substrate and biomass in a complete-mix reactor 367 367 373 377 380 392 Contents vii 10 Sedimentation 10.1 Introduction 10.2 Types of settling 10.3 Discrete settling 10.4 Flocculent settling 10.5 Zone settling 421 421 423 425 433 436 11 Aeration 11.1 Introduction 11.2 Fundamentals of gas transfer 11.3 Kinetics of aeration 11.4 Factors of influence in oxygen transfer 11.5 Oxygen transfer rate in the field and under standard conditions 11.6 Other aeration coefficients 11.7 Mechanical aeration systems 11.8 Diffused air aeration systems 11.9 Aeration tests 11.10 Gravity aeration 457 457 458 464 466 470 470 474 477 478 482 PART THREE STABILISATION PONDS 12 Overview of stabilisation ponds 495 13 Facultative ponds 13.1 Introduction 13.2 Description of the process 13.3 Influence of algae 13.4 Influence of environmental conditions 13.5 Design criteria 13.6 Estimation of the effluent BOD concentration 13.7 Pond arrangements 13.8 Sludge accumulation 13.9 Operational characteristics 13.10 Polishing of pond effluents 502 502 503 505 508 512 518 532 533 534 534 14 System of anaerobic ponds followed by facultative ponds 14.1 Introduction 14.2 Description of the process 14.3 Design criteria for anaerobic ponds 14.4 Estimation of the effluent BOD concentration from the anaerobic pond 14.5 Design of facultative ponds following anaerobic ponds 14.6 Sludge accumulation in anaerobic ponds 540 540 541 542 545 547 547 15 Facultative aerated lagoons 15.1 Introduction 15.2 Description of the process 15.3 Design criteria 552 552 552 553 viii Contents 15.4 15.5 15.6 15.7 15.8 Estimation of the effluent BOD concentration Oxygen requirements Aeration system Power requirements Sludge accumulation 554 557 558 558 560 16 Complete-mix aerated lagoons followed by sedimentation ponds 16.1 Introduction 16.2 Description of the process 16.3 Design criteria for the complete-mix aerated lagoons 16.4 Estimation of the effluent BOD concentration from the aerated lagoon 16.5 Oxygen requirements in the aerated lagoon 16.6 Power requirements in the aerated lagoon 16.7 Design of the sedimentation pond 564 564 565 566 17 Removal of pathogenic organisms 17.1 Introduction 17.2 Process description 17.3 Estimation of the effluent coliform concentration 17.4 Quality requirements for the effluent 17.5 Design criteria for coliform removal 17.6 Removal of helminth eggs 578 578 578 579 590 592 604 18 Nutrient removal in ponds 18.1 Nitrogen removal 18.2 Phosphorus removal 610 611 615 19 Ponds for the post-treatment of the effluent from anaerobic reactors 617 20 Construction of stabilisation ponds 20.1 Introduction 20.2 Location of the ponds 20.3 Deforestation, cleaning and excavation of the soil 20.4 Slopes 20.5 Bottom of the ponds 20.6 Inlet devices 20.7 Outlet devices 621 621 621 623 623 626 627 630 21 Maintenance and operation of stabilisation ponds 21.1 Introduction 21.2 Operational staff 21.3 Inspection, sampling and measurements 21.4 Operation start-up 21.5 Operational problems 632 632 633 633 633 638 22 Management of the sludge from stabilisation ponds 22.1 Preliminaries 644 644 567 569 570 570 Contents 22.2 Characteristics and distribution of the sludge in stabilisation ponds 22.3 Removal of sludge from stabilisation ponds ix 645 646 PART FOUR ANAEROBIC REACTORS 23 Introduction to anaerobic treatment 23.1 Applicability of anaerobic systems 23.2 Positive aspects 659 659 661 24 Principles of anaerobic digestion 24.1 Introduction 24.2 Microbiology of anaerobic digestion 24.3 Biochemistry of anaerobic digestion 24.4 Environmental requirements 663 663 664 667 681 25 Biomass in anaerobic systems 25.1 Preliminaries 25.2 Biomass retention in anaerobic systems 25.3 Evaluation of the microbial mass 25.4 Evaluation of the microbial activity 697 697 697 700 702 26 Anaerobic treatment systems 26.1 Preliminaries 26.2 Conventional systems 26.3 High-rate systems 26.4 Combined treatment systems 709 709 710 716 726 27 Design of anaerobic reactors 27.1 Anaerobic filters 27.2 Upflow anaerobic sludge blanket reactors 728 728 740 28 Operational control of anaerobic reactors 28.1 Importance of operational control 28.2 Operational control of the treatment system 28.3 Start-up of anaerobic reactors 28.4 Operational troubleshooting 774 774 777 791 799 29 Post-treatment of effluents from anaerobic reactors 29.1 Applicability and limitations of the anaerobic technology 29.2 Main alternatives for the post-treatment of effluents from anaerobic reactors 805 805 810 Preface The implementation of wastewater treatment plants has been so far a challenge for most countries. Economical resources, political will, institutional strength and cultural background are important elements defining the trajectory of pollution control in many countries. Technological aspects are sometimes mentioned as being one of the reasons hindering further developments. However, as shown in this book, the vast array of available processes for the treatment of wastewater should be seen as an incentive, allowing the selection of the most appropriate solution in technical and economical terms for each community or catchment area. For almost all combinations of requirements in terms of effluent quality, land availability, construction and running costs, mechanisation level and operational simplicity there will be one or more suitable treatment processes. Biological wastewater treatment is very much influenced by climate. Temperature plays a decisive role in some treatment processes, especially the natural-based and non-mechanised ones. Warm temperatures decrease land requirements, enhance conversion processes, increase removal efficiencies and make the utilisation of some treatment processes feasible. Some treatment processes, such as anaerobic reactors, may be utilised for diluted wastewater, such as domestic sewage, only in warm climate areas. Other processes, such as stabilisation ponds, may be applied in lower temperature regions, but occupying much larger areas and being subjected to a decrease in performance during winter. Other processes, such as activated sludge and aerobic biofilm reactors, are less dependent on temperature, as a result of the higher technological input and mechanisation level. The main purpose of the book is to present the technologies for urban wastewater treatment as applied to the specific condition of warm temperature, with the related implications in terms of design and operation. There is no strict definition for the range of temperatures that fall into this category, since the book always presents how to correct parameters, xi xii Preface rates and coefficients for different temperatures. In this sense, subtropical and even temperate climate are also indirectly covered, although most of the focus lies on the tropical climate. Another important point is that most warm climate regions are situated in developing countries. Therefore, the book casts a special view on the reality of these countries, in which simple, economical and sustainable solutions are strongly demanded. All technologies presented in the book may be applied in developing countries, but of course they imply different requirements in terms of energy, equipment and operational skills. Whenever possible, simple solutions, approaches and technologies are presented and recommended. Considering the difficulty in covering all different alternatives for wastewater collection, the book concentrates on off-site solutions, implying collection and transportation of the wastewater to treatment plants. No on-site solutions, such as latrines and septic tanks, are analysed. Also, stronger focus is given to separate sewerage systems, although the basic concepts are still applicable to combined systems, especially under dry weather conditions. Furthermore, emphasis is given to urban wastewater, that is, mainly domestic sewage plus some additional small contribution from non-domestic sources, such as industries. Hence, the book is not directed specifically to industrial wastewater treatment, given the specificities of this type of effluent. Another specific view of the book is that it details biological treatment processes. No physical–chemical wastewater treatment processes are covered, although some physical operations, such as sedimentation and aeration, are dealt with since they are an integral part of some biological treatment processes. The book’s proposal is to present in a balanced way theory and practice of wastewater treatment, so that a conscious selection, design and operation of the wastewater treatment process may be practised. Theory is considered essential for the understanding of the working principles of wastewater treatment. Practice is associated with the direct application of the concepts for conception, design and operation. In order to ensure the practical and didactic view of the book, 371 illustrations, 322 summary tables and 117 examples are included. All major wastewater treatment processes are covered by full and interlinked design examples which are built up throughout the book, from the determination of the wastewater characteristics, the impact of the discharge into rivers and lakes, the design of several wastewater treatment processes and the design of the sludge treatment and disposal units. The 55 chapters are divided into 7 parts, namely: (1) Introduction to wastewater characteristics, treatment and disposal; (2) Basic principles of wastewater treatment; (3) Stabilisation ponds; (4) Anaerobic reactors; (5) Activated sludge; (6) Aerobic biofilm reactors; and (7) Sludge treatment and disposal. Part 1 (Introduction to wastewater characteristics, treatment and disposal) presents an integrated view of water quality and wastewater treatment, analysing wastewater characteristics (flow and major constituents), the impact of the discharge into receiving water bodies and a general overview of wastewater treatment and sludge treatment and disposal. Part 1 is more introductory, and may be used Preface xiii as teaching material for undergraduate courses in civil engineering, environmental engineering, environmental sciences and related courses. Part 2 (Basic principles of wastewater treatment) is also introductory, but at a higher level of detailing. The core of this part is the unit operations and processes associated with biological wastewater treatment. The major topics covered are: microbiology and ecology of wastewater treatment; reaction kinetics and reactor hydraulics; conversion of organic and inorganic matter; sedimentation; aeration. Part 2 may be used as part of postgraduate courses in civil engineering, environmental engineering, environmental sciences and related courses, either as part of disciplines on wastewater treatment or unit operations and processes. Parts 3 to 6 are the central part of the book, being structured according to the major wastewater treatment processes (stabilisation ponds, anaerobic reactors, activated sludge and aerobic biofilm reactors). In each part, all major process technologies and variants are fully covered, including main concepts, working principles, expected removal efficiencies, design criteria, design examples, construction aspects and operational guidelines. Similarly to Part 2, Parts 3 to 6 can be used in postgraduate courses in civil engineering, environmental engineering, environmental sciences and related courses. Part 7 (Sludge treatment and disposal) covers in detail sludge characteristics, production, treatment (thickening, dewatering, stabilisation, pathogen removal) and disposal (land application for agricultural purposes, sanitary landfills, landfarming and other methods). Environmental and public health issues are fully described. Possible academic uses for this part are same as those from Parts 3 to 6. Besides being used as a textbook at academic institutions, it is believed that the book may be an important reference for practicing professionals, such as engineers, biologists, chemists and environmental scientists, acting in consulting companies, water authorities and environmental agencies. The present book is based on a consolidated, integrated and updated version of a series of six books written by the authors in Brazil, covering the topics presented in the current book, with the same concern for didactic approach and balance between theory and practice. The huge success of the Brazilian books, used at most graduate and post-graduate courses at Brazilian universities, besides consulting companies and water and environmental agencies, was the driving force for the preparation of this international version. In this version, the book aims at presenting consolidated technology based on worldwide experience available from international literature. However, it should be recognised that a significant input comes from the Brazilian experience, considering the background and working practice of all authors. Brazil is a large country with many geographical, climatic, economical, social and cultural contrasts, reflecting well the reality encountered in many countries in the world. Besides, it should be mentioned that Brazil is currently one of the leading countries in the world as regards the application of anaerobic technology to domestic sewage treatment, and the post-treatment of anaerobic effluents. Regarding this point, the authors would like to show their recognition for the Brazilian Research Programme on Basic Sanitation (PROSAB), which, through several years of intensive, applied, xiv Preface cooperative research has led to the consolidation of anaerobic treatment and aerobic/anaerobic post-treatment, which are currently widely applied in full-scale plants in Brazil. Consolidated results achieved by PROSAB are included in various parts of the book, representing invaluable and updated information applicable to warm climate regions. Parts 1 to 5 were written by the two main authors. The book counted with the invaluable participation of Cleverson Vitorio Andreoli and Fernando Fernandes, who acted as editors for Part 7, and of several specialists, who acted as authors in the chapters in Parts 6 and 7. The authors of these chapters are: Aderlene Inˆes de Lara, Deize Dias Lopes, Dione Mari Morita, Eduardo Sabino Pegorini, Hilton Fel´ıcio dos Santos, Marcelo Antonio Teixeira Pinto, Maur´ıcio Luduvice, Ricardo Franci Gon¸calves, Sandra M´arcia Ces´ario Pereira da Silva, Vanete Thomaz Soccol. Technical review of the English version of Part 7 was made by Hilton Fel´ıcio dos Santos. Financial support for the translation of Part 7 was provided by SANEPAR (Paran´a Water and Sanitation Company, Brazil). Many colleagues, students and professionals contributed with useful suggestions, reviews and incentives for the Brazilian books that were the seed for this international version. It would be impossible to list all of them here, but our heartfelt appreciation is acknowledged. The authors would like to express their recognition for the support provided by the Department of Sanitary and Environmental Engineering at the Federal University of Minas Gerais, Brazil, at which the two authors work. The department provided institutional and financial support for this international version, which is in line with the university’s view of expanding and disseminating knowledge to society. Finally, the authors would like to show their appreciation to IWA Publishing, for their incentive and patience in following the development of this book throughout the two years of hard work. Marcos von Sperling Carlos Augusto de Lemos Chernicharo To Paulo and Margarida von Sperling, Vanessa and Bruno Guerra de Moura von Sperling and Jair and Dinorah Chernicharo Adriana, J´ulia, Daniel and Guilherme Chernicharo The authors BOOK AUTHORS Parts 1, 2, 3, 5 and 7 Marcos von Sperling PhD in Environmental Engineering (Imperial College, University of London, UK). Senior lecturer at the Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Brazil. Consultant to governmental and private companies in the field of water pollution control and wastewater treatment. [email protected] Parts 4 and 6 Carlos Augusto de Lemos Chernicharo PhD in Environmental Engineering (University of Newcastle-upon-Tyne, UK). Senior lecturer at the Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Brazil. Consultant to governmental and private companies in the field of wastewater treatment. [email protected] ASSOCIATE EDITORS (PART 7) Cleverson Vit´orio Andreoli, PhD. Federal University of Paran´a (UFPR). Paran´a Water and Sanitation Company (SANEPAR), Brazil. [email protected] Fernando Fernandes, PhD. Londrina State University (UEL), Brazil. [email protected] xvii xviii The authors CHAPTER AUTHORS (PARTS 6 AND 7) Aderlene Inˆes de Lara, PhD. Paran´a Water and Sanitation Company (SANEPAR), Brazil. [email protected] Deize Dias Lopes, PhD. Londrina State University (UEL), Brazil. [email protected] Dione Mari Morita, PhD. University of S˜ao Paulo (USP), Brazil. [email protected] Eduardo Sabino Pegorini. Paran´a Water and Sanitation Company (SANEPAR), Brazil. [email protected] H´ılton Fel´ıcio dos Santos, PhD. Consultant, Brazil. [email protected] (also acted as technical reviewer to Part 7) Marcelo Antonio Teixeira Pinto, MSc. Federal District Water and Sanitation Company (CAESB), Brazil. [email protected] Maur´ıcio Luduvice, PhD. MSc. Federal District Water and Sanitation Company (CAESB), Brazil. [email protected] Ricardo Franci Gon¸calves, PhD. Federal University of Esp´ırito Santo, Brazil. [email protected] Sandra M´arcia Ces´ario Pereira da Silva, PhD. Londrina State University (UEL), Brazil. [email protected] Vanete Thomaz Soccol, PhD. Federal University of Paran´a (UFPR), Brazil. [email protected] List of authors by chapter Part 1 2 3 4 5 6 7 Chapter 1 to 6 7 to 11 12 to 22 23 to 29 30 to 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 Author Marcos von Sperling Marcos von Sperling Marcos von Sperling Carlos Augusto de Lemos Chernicharo Marcos von Sperling Ricardo Franci Gon¸calves Carlos Augusto de Lemos Chernicharo, Ricardo Franci Gon¸calves Ricardo Franci Gon¸calves Ricardo Franci Gon¸calves Marcos von Sperling, Cleverson Vit´orio Andreoli Marcos von Sperling, Ricardo Franci Gon¸calves Sandra M.C.P. da Silva, Fernando Fernandes, Vanete T. Soccol, Dione M. Morita Maur´ıcio Luduvice Ricardo Franci Gon¸calves, Maur´ıcio Luduvice, Marcos von Sperling Marcelo Teixeira Pinto Fernando Fernandes, Deize D. Lopes, Cleverson V. Andreoli, Sandra M.C.P. da Silva Cleverson V. Andreoli, Eduardo S. Pegorini, Fernando Fernandes, Hilton F. dos Santos Maur´ıcio Luduvice, Fernando Fernandes Aderlene I. de Lara, Cleverson V. Andreoli, Eduardo S. Pegorini xix Biological Wastewater Treatment in Warm Climate Regions Marcos von Sperling and Carlos Augusto de Lemos Chernicharo Department of Sanitary and Environmental Engineering Federal University of Minas Gerais, Brazil VOLUME TWO Associate editors (Part VII): Cleverson Vitorio Andreoli and Fernando Fernandes Published by IWA Publishing, Alliance House, 12 Caxton Street, London SW1H 0QS, UK Telephone: +44 (0) 20 7654 5500; Fax: +44 (0) 20 7654 5555; Email: [email protected] Website: www.iwapublishing.com First published 2005 Reprinted 2006 C 2005 IWA Publishing Copy-edited and typeset by TechBooks, India Printed by TJ International, Padstow, UK Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the UK Copyright, Designs and Patents Act (1998), no part of this publication may be reproduced, stored or transmitted in any form or by any means, without the prior permission in writing of the publisher, or, in the case of photographic reproduction, in accordance with the terms of licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licenses issued by the appropriate reproduction rights organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to IWA Publishing at the address printed above. The publisher makes no representation, expressed 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 or of the editors, and should not be acted upon without independent consideration and professional advice. IWA and the editors 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 Library of Congress Cataloguing-in-Publication Data A catalogue record for this book is available from the Library of Congress ISBN: 1 84339 002 7 (set); 1 84339 107 4 (this volume) Contents Volume Two PART FIVE ACTIVATED SLUDGE 30 Activated sludge process and main variants 30.1 Introduction 30.2 Variants of the activated sludge process 839 839 842 31 Principles of organic matter removal in continuous-flow activated sludge systems 31.1 Preliminaries 31.2 Sludge age in activated sludge systems 31.3 Suspended solids concentration in the reactor 31.4 Calculation of the reactor volume 31.5 Substrate removal 31.6 Soluble BOD and total BOD in the effluent 31.7 Sludge digestion in the reactor 31.8 Recirculation of the activated sludge 31.9 Production and removal of excess sludge 31.10 Oxygen requirements 31.11 Nutrient requirements 31.12 Influence of the temperature 31.13 Functional relations with the sludge age 855 855 857 857 859 862 865 869 872 877 886 893 896 897 32 Design of continuous-flow activated sludge reactors for organic matter removal 32.1 Selection of the sludge age 32.2 Design parameters 32.3 Physical configuration of the reactor 32.4 Design details 906 906 908 909 912 v vi Contents 33 Design of activated sludge sedimentation tanks 33.1 Types of sedimentation tanks 33.2 Determination of the surface area required for secondary sedimentation tanks 33.3 Design details in secondary sedimentation tanks 33.4 Design of primary sedimentation tanks 915 915 916 937 939 34 Design example of an activated sludge system for organic matter removal 34.1 Introduction 34.2 Model parameters and coefficients 34.3 Design of the conventional activated sludge system 34.4 Summary of the design 942 942 943 944 957 35 Principles of biological nutrient removal 35.1 Introduction 35.2 Nitrogen in raw sewage and main transformations in the treatment process 35.3 Principles of nitrification 35.4 Principles of biological denitrification 35.5 Principles of biological phosphorus removal 959 959 961 965 978 986 36 Design of continuous-flow systems for biological nutrient removal 36.1 Biological nitrogen removal 36.2 Biological removal of nitrogen and phosphorus 997 997 1015 37 Intermittent operation systems (sequencing batch reactors) 37.1 Introduction 37.2 Principles of the process 37.3 Process variants 37.4 Design criteria for sequencing batch reactors 37.5 Design methodology for sequencing batch reactors 37.6 Design example of a sequencing batch reactor 1023 1023 1023 1026 1031 1034 1035 38 Activated sludge for the post-treatment of the effluents from anaerobic reactors 38.1 Design criteria and parameters 38.2 Design example of an activated sludge system for the post-treatment of the effluent from a UASB reactor 1045 39 Biological selectors 39.1 Introduction 39.2 Types of selectors 1055 1055 1057 40 Process control 40.1 Introduction 40.2 Basic concepts of process control 1061 1061 1063 1042 1042 Contents 40.3 Dissolved oxygen control 40.4 Solids control 40.5 Monitoring the system 41 Identification and correction of operational problems 41.1 Introduction 41.2 High concentrations of suspended solids in the effluent 41.3 High BOD concentrations in the effluent 41.4 High ammonia concentrations in the effluent vii 1065 1066 1073 1074 1074 1075 1098 1103 PART SIX AEROBIC BIOFILM REACTORS 42 Basic principles of aerobic biofilm reactors R.F. Gon¸calves 42.1 Introduction 42.2 Classification of aerobic biofilm reactors 42.3 Formation, structure and behaviour of biofilms 43 Trickling filters C.A.L. Chernicharo, R.F. Gon¸calves 43.1 Description of the technology 43.2 Design criteria 43.3 Construction aspects 43.4 Operational aspects 44 Rotating biological contactors R.F. Gon¸calves 44.1 Introduction 44.2 Description of the technology 44.3 Design criteria 44.4 Construction aspects and characteristics of the support medium 45 Submerged aerated biofilters R.F. Gon¸calves 45.1 Introduction 45.2 Description of the technology 45.3 Design criteria 45.4 Construction aspects 45.5 Operational aspects 1113 1113 1114 1115 1119 1119 1123 1130 1131 1135 1135 1135 1137 1140 1142 1142 1142 1150 1152 1153 PART SEVEN SLUDGE TREATMENT AND DISPOSAL 46 Introduction to sludge management M. von Sperling, C.V. Andreoli 1167 viii Contents 47 Sludge characteristics and production M. von Sperling, R.F. Gon¸calves 47.1 Sludge production in wastewater treatment systems 47.2 Sludge characteristics at each treatment stage 47.3 Fundamental relationships in sludge 47.4 Calculation of the sludge production 47.5 Mass balance in sludge treatment 48 Main contaminants in sludge S.M.C.P. da Silva, F. Fernandes, V.T. Soccol, D.M. Morita 48.1 Introduction 48.2 Metals 48.3 Trace organics 48.4 Pathogenic organisms 1170 1170 1172 1178 1182 1194 1197 1197 1198 1205 1206 49 Sludge stabilisation M. Luduvice 49.1 Introduction 49.2 Anaerobic digestion 49.3 Aerobic digestion 1214 50 Sludge thickening and dewatering R.F. Gon¸calves, M. Luduvice, M. von Sperling 50.1 Thickening and dewatering of primary and biological sludges 50.2 Sludge thickening 50.3 Sludge conditioning 50.4 Overview on the performance of the dewatering processes 50.5 Sludge drying beds 50.6 Centrifuges 50.7 Filter press 50.8 Belt presses 50.9 Thermal drying 1242 51 Pathogen removal from sludge M.T. Pinto 51.1 Introduction 51.2 General principles 51.3 Mechanisms to reduce pathogens 51.4 Processes to reduce pathogens 51.5 Operation and control 52 Assessment of sludge treatment and disposal alternatives F. Fernandes, D.D. Lopes, C.V. Andreoli, S.M.C.P. da Silva 52.1 Introduction 52.2 Sustainable point of view 52.3 Trends in sludge management in some countries 1214 1215 1233 1242 1244 1247 1256 1257 1265 1273 1280 1284 1286 1286 1287 1289 1293 1310 1315 1315 1316 1316 Contents 52.4 Aspects to be considered prior to the assessment of alternatives 52.5 Criterion for selecting sludge treatment and final disposal alternatives 52.6 Sludge management at the treatment plant 53 Land application of sewage sludge C.V. Andreoli, E. S. Pegorini, F. Fernandes, H.F. dos Santos 53.1 Introduction 53.2 Beneficial use 53.3 Requirements and associated risks 53.4 Handling and management 53.5 Storage, transportation and application of biosolids 53.6 Operational aspects of biosolid land application 53.7 Landfarming 54 Sludge transformation and disposal methods M. Luduvice, F. Fernandes 54.1 Introduction 54.2 Thermal drying 54.3 Wet air oxidation 54.4 Incineration 54.5 Landfill disposal 55 Environmental impact assessment and monitoring of final sludge disposal A. I. de Lara, C.V. Andreoli, E.S. Pegorini 55.1 Introduction 55.2 Potentially negative environmental impacts 55.3 Monitoring indicators and parameters 55.4 Monitoring plan Index ix 1318 1321 1326 1328 1328 1329 1335 1343 1352 1357 1367 1373 1373 1374 1375 1378 1381 1392 1392 1393 1396 1398 1409
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