Wastewater Characteristics, Treatment and Disposal ?· Biological Wastewater Treatment Series VOLUME…

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Wastewater Characteristics,

Treatment and Disposal

Biological Wastewater Treatment Series

The Biological Wastewater Treatment series is based on the book BiologicalWastewater Treatment in Warm Climate Regions and on a highly acclaimed set ofbest selling textbooks. This international version is comprised by six textbooksgiving a state-of-the-art presentation of the science and technology of biologicalwastewater treatment.

Titles in the Biological Wastewater Treatment series are:

Volume 1: Wastewater Characteristics, Treatment and DisposalVolume 2: Basic Principles of Wastewater TreatmentVolume 3: Waste Stabilisation PondsVolume 4: Anaerobic ReactorsVolume 5: Activated Sludge and Aerobic Biofilm ReactorsVolume 6: Sludge Treatment and Disposal

Biological Wastewater Treatment Series

VOLUME ONE

Wastewater Characteristics,Treatment and Disposal

Marcos von SperlingDepartment of Sanitary and Environmental EngineeringFederal University of Minas Gerais, Brazil

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: publications@iwap.co.uk

Website: www.iwapublishing.com

First published 2007

C 2007 IWA Publishing

Copy-edited and typeset by Aptara Inc., New Delhi, India

Printed by Lightning Source

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 161 9

ISBN 13: 9781843391616

Contents

Preface viiThe author xi

1 Introduction to water quality and water pollution 11.1 Introduction 11.2 Uses of water 31.3 Water quality requirements 31.4 Water pollution 6

2 Wastewater characteristics 92.1 Wastewater flowrates 92.2 Wastewater composition 28

3 Impact of wastewater discharges to water bodies 773.1 Introduction 773.2 Pollution by organic matter and stream self purification 773.3 Contamination by pathogenic microorganisms 1233.4 Eutrophication of lakes and reservoirs 1313.5 Quality standards for wastewater discharges and waterbodies 150

4 Overview of wastewater treatment systems 1634.1 Wastewater treatment levels 1634.2 Wastewater treatment operations, processes and systems 1654.3 Preliminary treatment 1784.4 Primary treatment 1794.5 Secondary treatment 1804.6 Removal of pathogenic organisms 2154.7 Analysis and selection of the wastewater treatment process 215

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vi Contents

5 Overview of sludge treatment and disposal 2425.1 Introduction 2425.2 Relationships in sludge: solids levels, concentration

and flow 2465.3 Quantity of sludge generated in the wastewater

treatment processes 2495.4 Sludge treatment stages 2525.5 Sludge thickening 2555.6 Sludge stabilisation 2565.7 Sludge dewatering 2585.8 Sludge disinfection 2685.9 Final disposal of the sludge 272

6 Complementary items in planning studies 2776.1 Preliminary studies 2776.2 Design horizon and staging periods 2796.3 Preliminary design of the alternatives 2816.4 Economical study of alternatives 282

References 287

Preface

The present series of books has been produced based on the book Biologicalwastewater treatment in warm climate regions, written by the same authors andalso published by IWA Publishing. The main idea behind this series is the sub-division of the original book into smaller books, which could be more easilypurchased and used.

The implementation of wastewater treatment plants has been so far a challengefor most countries. Economical resources, political will, institutional strength andcultural background are important elements defining the trajectory of pollutioncontrol in many countries. Technological aspects are sometimes mentioned asbeing one of the reasons hindering further developments. However, as shown inthis series of books, the vast array of available processes for the treatment ofwastewater should be seen as an incentive, allowing the selection of the mostappropriate solution in technical and economical terms for each community orcatchment area. For almost all combinations of requirements in terms of effluentquality, land availability, construction and running costs, mechanisation level andoperational simplicity there will be one or more suitable treatment processes.

Biological wastewater treatment is very much influenced by climate. Tempera-ture plays a decisive role in some treatment processes, especially the natural-basedand non-mechanised ones. Warm temperatures decrease land requirements, en-hance conversion processes, increase removal efficiencies and make the utilisationof some treatment processes feasible. Some treatment processes, such as anaer-obic reactors, may be utilised for diluted wastewater, such as domestic sewage,only in warm climate areas. Other processes, such as stabilisation ponds, may beapplied in lower temperature regions, but occupying much larger areas and beingsubjected to a decrease in performance during winter. Other processes, such asactivated sludge and aerobic biofilm reactors, are less dependent on temperature,

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as a result of the higher technological input and mechanisation level. The mainpurpose of this series of books is to present the technologies for urban wastewatertreatment as applied to the specific condition of warm temperature, with the relatedimplications in terms of design and operation. There is no strict definition for therange of temperatures that fall into this category, since the books always presenthow to correct parameters, rates and coefficients for different temperatures. In thissense, subtropical and even temperate climate are also indirectly covered, althoughmost of the focus lies on the tropical climate.

Another important point is that most warm climate regions are situated indeveloping countries. Therefore, the books cast a special view on the reality ofthese countries, in which simple, economical and sustainable solutions are stronglydemanded. All technologies presented in the books may be applied in developingcountries, but of course they imply different requirements in terms of energy, equip-ment and operational skills. Whenever possible, simple solutions, approaches andtechnologies are presented and recommended.

Considering the difficulty in covering all different alternatives for wastewatercollection, the books concentrate on off-site solutions, implying collection andtransportation of the wastewater to treatment plants. No off-site solutions, suchas latrines and septic tanks are analysed. Also, stronger focus is given to separatesewerage systems, although the basic concepts are still applicable to combinedand mixed systems, especially under dry weather conditions. Furthermore, em-phasis is given to urban wastewater, that is, mainly domestic sewage plus someadditional small contribution from non-domestic sources, such as industries.Hence, the books are not directed specifically to industrial wastewater treatment,given the specificities of this type of effluent. Another specific view of the booksis that they detail biological treatment processes. No physical-chemical wastew-ater treatment processes are covered, although some physical operations, such assedimentation and aeration, are dealt with since they are an integral part of somebiological treatment processes.

The books proposal is to present in a balanced way theory and practice ofwastewater treatment, so that a conscious selection, design and operation of thewastewater treatment process may be practised. Theory is considered essentialfor the understanding of the working principles of wastewater treatment. Practiceis associated to the direct application of the concepts for conception, design andoperation. In order to ensure the practical and didactic view of the series, 371 illus-trations, 322 summary tables and 117 examples are included. All major wastewatertreatment processes are covered by full and interlinked design examples which arebuilt up throughout the series and the books, from the determination of the waste-water characteristics, the impact of the discharge into rivers and lakes, the designof several wastewater treatment proc