Modeling Water Quality in Distribution Systems

427 Pages·2012·32.679 MB·English

by  Robert Clark

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Water quality modeling is a powerful tool to help utilities understand the pro- istd Modeling
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systems. This expanded and updated second edition addresses many devel- b
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opments that have taken place in the field over more than a decade. It includes ti
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This book will show you how to set up a realistic mathematical simulation Water Quality
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of your distribution system and water quality so you can determine the fate of yW
contaminants as they travel through the distribution system. You will see how s
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to model a wide range of operational and design variables. Experiment with
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various scenarios to model and monitor TTHMs, disinfectant decay, chemical
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reactions, supply and demand over time, hydraulics, tank mixing, blended
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waters, and many other parameters. in Distribution Systems
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Whether you are new to water quality modeling or a longtime practi-
tioner, you will find a vast wealth of knowledge from an esteemed expert in u
the field and a pioneering developer of EPANET, author Robert M. Clark. a
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Second Edition
Robert M. Clark
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Modeling
Water Quality

in Distribution Systems
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Modeling
Water Quality

in Distribution Systems
Second Edition
Robert M. Clark
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Modeling Water Quality in Distribution Systems, Second Edition
Copyright © 2012 American Water Works Association
All rights reserved. No part of this publication may be reproduced or transmitted in any form
or by any means, electronic or mechanical, including photocopy, recording, or any information
or retrieval system, except in the form of brief excerpts or quotations for review purposes,
without the written permission of the publisher.
The authors, contributors, editors, and publisher do not assume responsibility for the validity
of the content or any consequences of its use. In no event will AWWA be liable for direct,
indirect, special, incidental, or consequential damages arising out of the use of information
presented in this book. In particular, AWWA will not be responsible for any costs, including,
but not limited to, those incurred as a result of lost revenue. In no event shall AWWA’s liability
exceed the amount paid for the purchase of this book.
AWWA Publications Manager: Gay Porter De Nileon
Project Manager/Technical Editor: Martha Ripley Gray
Production: Cheryl Armstrong
Cover Art: Karen Staab
Library of Congress Cataloging-in-Publication Data
Clark, Robert Maurice.
Modeling water quality in distribution systems / Robert M. Clark. -- 2nd ed.
p. cm.
Rev. ed. of: Modeling water quality in drinking water distribution systems / Robert M. Clark,
Walter M. Grayman. 1998.
Includes bibliographical references and index.
ISBN 978-1-58321-816-7
1. Water quality--Computer simulation. 2. Water--Distribution--Computer simulation. I.
Clark, Robert Maurice. Modeling water quality in drinking water distribution systems. II.
Title.
TD482.C58 2011
628.1’44--dc23
2011022334
Printed in the United States of America
6666 West Quincy Avenue
Denver, CO 80235-3098
303.794.7711
www.awwa.org
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Dedication
To my supportive and understanding family, especially my
grandchildren, Thomas, Nicholas, Benjamin, and Eleanor. They have
helped me to appreciate and understand the real meaning of life.
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Contents
List of Figures xiii
List of Tables xix
Preface xxi
Acknowledgments xxv
1 Characteristics of US Water Supply Systems 1
Introduction .....................................................1
Water Scarcity Issues..............................................2
Water Security Issues .............................................4
Effects of Climate Change.........................................5
Organization of Water Supplies in the United States.................5
Common Elements in Water Systems...............................6
Basic Design and Operational Philosophies .........................9
References ......................................................11
2 Public Health and Regulatory Issues in Water Supply 13
Introduction ....................................................13
The Distribution System as a Barrier to Waterborne Disease .........15
Safe Drinking Water Act.........................................18
Recommendations From the NRC Report .........................22
Current Activities ...............................................25
References ......................................................25
3 Modeling and Monitoring Water Quality: An Overview 27
Introduction ....................................................27
Modeling Applications...........................................28
Types of Distribution System Models..............................29
Model Applications..............................................31
Model Calibration...............................................32
Regulatory Implications..........................................34
Monitoring Strategies............................................34
Commercial Hydraulic–Water Quality Modeling Software..........34
Additional Modeling Tools.......................................35
Optimization Tools..............................................39
References ......................................................41
vii
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4 Modeling and Monitoring Chemical and Microbiological
Contaminants 45
Introduction ....................................................45
Distribution System Water Quality................................46
Monitoring Principles............................................48
Establishing Monitoring Objectives ...............................50
Monitoring Case Studies .........................................54
Summary .......................................................57
References ......................................................59
5 Hydraulic Modeling Principles 61
Introduction ....................................................61
Hydraulic Principles .............................................61
Analysis Methods................................................65
Reducing Network Complexity...................................65
Minor Losses....................................................68
Heads at Junctions as Unknowns .................................71
Corrective Flow Rates Around Loops of Network
Considered Unknowns.......................................71
Solution Techniques .............................................72
Network Characterization........................................73
Hydraulic Transients.............................................73
Application of Models ...........................................75
Modeling Temporal Variations....................................80
Fire-Flow Provisions .............................................81
Flushing Water Mains............................................82
References ......................................................83
6 Water Quality Modeling Principles 85
Introduction ....................................................85
Water Quality Models Inputs and Application .....................86
Water Quality Fundamentals.....................................87
EPANET.......................................................89
QUALNET....................................................101
Solution Methods ..............................................103
Event-Driven Method...........................................104
Commercial Hydraulic–Water Quality Modeling Software.........105
References .....................................................105
viii
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7 Modeling Individual Constituents in Drinking Water:
Total Trihalomethanes and Disinfectant Decay 107
Introduction ...................................................107
Chemistry of Chlorine in Water .................................108
Chemistry of Chloramines in Water..............................111
Modeling the Decay of Chlorine Residuals........................112
Modeling the Decay of Chloramine Residuals.....................121
Modeling By-product Formation.................................123
Exposure to DBPs in Distribution Systems........................126
References .....................................................128
8 Early Modeling Studies 131
Introduction ...................................................131
North Penn Water Authority Study ..............................132
South Central Connecticut Regional Water Authority Case Study..135
The North Marin Case Study....................................145
AwwaRF/USEPA Study ........................................159
Conclusions....................................................161
References .....................................................162
9 Case Study Applications 163
Introduction ...................................................163
Cabool, Missouri, Case Study....................................164
Gideon, Missouri, Case Study....................................165
Walkerton, Canada, Case Study .................................168
Dover Township, New Jersey, Case Study .........................169
East Bay Municipal Utility District Case Study....................171
Camp Lejeune, North Carolina, Case Study ......................173
Regulatory Studies..............................................176
References .....................................................181
10 Advanced Concepts in Water Quality Modeling 183
Introduction ...................................................183
Geospatial Tools................................................183
Integrating GIS and Water Quality Modeling.....................186
Multispecies Modeling..........................................193
Distribution System Security ....................................200
Water Quality and Pressure Transients ...........................206
Emerging Research Areas........................................207
References .....................................................219
ix
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