1、 Internal Corrosion Control in Water Distribution Systems AWWA MANUAL M58 First Edition M58 book.indb 1 11/17/2010 4:24:29 PM Copyright 2011 American Water Works Association. All Rights Reserved. MANUAL OF WATER SUPPL Y PRACTICES M58, First Edition Internal Corrosion Control in Water Distribution Sy
2、stems Copyright 2011 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
3、or quotations for review purposes, without the written permission of the publisher. Disclaimer The authors, contributors, editors, and publisher do not assume responsibility for the validity of the content or any consequences of their use. In no event will AWWA be liable for direct, indirect, specia
4、l, 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 AWWAs liability exceed the amount paid for the
5、 purchase of this book. Project Manager: Melissa Valentine Editor: Deborah Lynes Production Editor: Cheryl Armstrong Manuals Coordinator: Molly Beach Library of Congress Cataloging-in-Publication Data. Hill, Christopher P.Internal corrosion impacts in drinking water distribution systems / by Christo
6、pher P. Hill, Abigail F. Cantor. - 1st ed.p. cm. - (AWWA manual ; M58)Includes bibliographical references and index.ISBN 978-1-58321-790-0 (alk. paper)1. Water-pipes-Corrosion. 2. Drinking water-Contamination. 3. Water-Distribution. 4. Corrosion and anti-corrosives-Testing. I. Cantor, Abigail F. II.
7、 Title. TD491.H64 2010628.144-dc222010016956 Printed in the United States of America American Water Works Association 6666 West Quincy Ave. Denver, CO 80235 Printed on recycled paper M58 book.indb 2 11/17/2010 4:24:29 PM Copyright 2011 American Water Works Association. All Rights Reserved. Contents
8、iii List of Figures, v List of Tables, ix Preface, xi Acknowledgments, xiii Overview of Internal Corrosion Impacts Chapter 1 in Drinking Water Distribution Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Introduction, 1 Purpose of This Manual, 2 Customer and Infrastructure Impa
9、cts of Internal Corrosion, 2 Regulatory Impacts, 6 Additional Reading, 9 References, 10 Fundamentals of Internal Corrosion and Metal Release Chapter 2 . . . . . . . . . 13 Introduction, 13 Mechanisms of Metal Release by Uniform Corrosion, 13 Mechanisms of Metal Release by Nonuniform Corrosion, 23 Ot
10、her Mechanisms of Metal Release, 27 Summary, 28 Additional Reading, 28 References, 28 Water Quality Monitoring and Assessment of Internal Chapter 3 Corrosion and Increased Metals Concentrations . . . . . . . . . . . . . . . . . . . . . . 31 Introduction, 31 Water Quality Considerations, 32 Developin
11、g a Water Quality Monitoring Program, 49 Assessing the Cause of Internal Corrosion and Metals Release, 53 Summary, 55 Additional Reading, 56 References, 57 Corrosion Control Techniques Chapter 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Introduction, 61 Distribution System Des
12、ign Considerations, 62 Chemical Treatment, 74 Conclusion, 100 References, 101 M58 book.indb 3 11/17/2010 4:24:29 PM Copyright 2011 American Water Works Association. All Rights Reserved. iv Implementing Corrosion Control Treatment Chapter 5 . . . . . . . . . . . . . . . . . . 103 Introduction, 103 Co
13、rrosion Indexes, 105 Bench Testing, 105 Examination of Pipe Scales, 109 Pipe Loops, 110 Coupon Studies, 115 PRS Monitoring Stations, 117 Electrochemistry Loops, 120 Premise Plumbing Profiles, 126 Reservoir Profiles, 127 Summary, 128 References, 129 Conducting Pilot Studies and Monitoring Chapter 6 E
14、ffectiveness of Corrosion Control Treatment . . . . . . . . . . . . . . . . . . . . . . . 131 Introduction, 131 Conducting a Distribution System Pilot Study, 132 Monitoring the Effect of Corrosion Control Treatment, 140 Summary, 148 References, 148 Appendix A Achieving pH Stability . . . . . . . . .
15、 . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Appendix B A Case Study: Causes of and Actions Taken to Control Lead Release in the D . C . Distribution System . . . . . . . . . . . . . . . 157 Appendix C North American Corrosion Control Needs and Strategies . . . . . 173 Index . . . . . .
16、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 M58 book.indb 4 11/17/2010 4:24:29 PM Copyright 2011 American Water Works Association. All Rights Reserved. Figures v 1-1 Red water sample from a US distribution system, 3 1-2 Number of
17、large US water systems exceeding the lead action level, 7 1-3 Comparison of 90th percentile LCR monitoring data for 166 large public water systems, 7 2-1 Typical battery, 15 2-2 Typical water and metal pipe “battery”, 15 2-3 Barrier between water and metal pipe, 16 2-4 Characteristic horseshoe-shape
18、d pit of erosion corrosion, 25 2-5 Example of microbially influenced pitting of copper pipe, 26 2-6 Another example of microbially influenced pitting of copper pipe, 26 3-1 Variation of buffer intensity with pH, 34 3-2 Relationship between alkalinity and DIC for various pH levels, 35 3-3 Effect of D
19、IC on buffer intensity, 36 3-4 Iron Pourbaix diagram for a carbonate-containing water at 25C and I = 0, 40 3-5 Impact of chloride-to-sulfate ratio on lead corrosion, 42 3-6 Precipitated iron as a protective barrier for microorganisms, 48 4-1 Asbestoscement pipe, 65 4-2 Bronze fitting, 65 4-3 Brass f
20、aucet, 65 4-4 Copper pipe, 65 4-5 Galvanized pipe, 66 4-6 Unlined cast-iron main, 67 4-7 Harvested lead service lines, 67 4-8 Plastic water supply pipe, 67 4-9 Branched (A) and grid/loop (B) designs, 68 4-10 Application of cementmortar lining, 71 4-11 Example of pipe before and after cleaning and li
21、ning, 71 4-12 Steel pipe with epoxy coating, 72 4-13 Typical liquid chemical feed system, 74 4-14 Typical dry chemical feed system, 75 4-15 Iron and manganese solubility, 82 4-16 Slurry slaker, 83 4-17 Paste slaker, 84 4-18 Ball mill lime slaker, 84 4-19 Examples of chemical inhibitors, 86 4-20 Thre
22、e polyphosphate structures, 87 4-21 Type of phosphate inhibitor used by water utilities, 90 4-22 Reasons for using phosphate inhibitors, 90 4-23 Orthophosphate feed system, 90 5-1 Diagram of pH adjustment chemical injected into line before water from hydropneumatic tank is exposed to atmospheric pre
23、ssure, 106 5-2 Apparatus setup for filtering calcium carbonate and other precipitates such as iron, manganese, and phosphate, 107 5-3 Pipes with lead-dioxide scales cut horizontally prior to XRD, 109 M58 book.indb 5 11/17/2010 4:24:29 PM Copyright 2011 American Water Works Association. All Rights Re
24、served. vi 5-4 Lead-speciated XRD patterns, 110 5-5 Example of a capped pipe ready for transportation, 110 5-6 Circulating-loop schematic, 111 5-7 Circulating loop with lead service lines, 112 5-8 Lead release during pipe-loop conditioning from pipe containing lead-oxide scales, 112 5-9 Metals relea
25、se over time in a stagnated lead pipe loop, 113 5-10 Flow-through system, view 1, 114 5-11 Flow-through system, view 2, 115 5-12 Data from a pipe loop that displays changes in lead (IV) release as the loop was alternated with chlorine and chloramine over time, 115 5-13 Typical metal coupons, 117 5-1
26、4 Typical coupon study apparatus, 117 5-15 Drawing of a PRS monitoring station, 119 5-16 Stacks of metal plates exposed to water replace pipe loops in the PRS monitoring stations, 119 5-17 Electrochemistry circulation pipe loop setup, 124 5-18 Schematic of electrochemical polarization cell used for
27、corrosion rate measurements, 124 5-19 Typical polarization cell design, 125 5-20 Corrosion rates from lead pipe with lead (IV) scale, 125 5-21 Example of a lead profile at a residential home with a lead service line, 127 5-22 Example of a lead profile at a residential home with galvanized internal p
28、lumbing and lead service line, 128 6-1 Example of maintaining chemical (pH) stability at the entry point, 133 6-2 Percent positive total coliforms in DC Water in relation to the addition of orthophosphate, 134 6-3 Precipitated phosphate, 135 6-4 Depth samplers used to collect grab samples from reser
29、voirs, 135 6-5 HPC results taken from a routine inside monitoring tap and a hydrant located next to the property, 136 6-6 Minimum alkalinity required to maintain a buffer intensity greater than or equal to 0.10 meq/L as a function of pH at 20C, 141 6-7 Lead profile water hammer graph taken from resi
30、dential homes in the District of Columbia from December 2003 to July 2005, 142 6-8 Potential-pH diagram for 1 mg/L free chlorine, showing the speciation of the chlorine system, the high ORP necessary for free chlorine stability, and the relationship to the water stability boundary, 142 6-9 Flowchart
31、 example of action taken when a regulated parameter is exceeded causing an excursion, 146 6-10 SOP flowchart for exceeding target levels, 147 A-1 Example of a dual-speed pump calibration curve, 150 A-2 WQP operations chart for pH/alkalinity adjustment, 152 A-3 WQP operations chart: soda ash and targ
32、et pH of 7.8, 152 A-4 Filling in WQP chart with sample data, 154 A-5 Working WQP operations chart, 154 M58 book.indb 6 11/17/2010 4:24:29 PM Copyright 2011 American Water Works Association. All Rights Reserved. vii B-1 The Washington Aqueduct service area, 158 B-2 History of LCR compliance in Washin
33、gton, D.C., 160 B-3 Peak dissolved lead levels in homes during lead profiles, 161 B-4 EMF-pH diagram for Pb-H 2 O-CO 2system, 162 B-5 DC Water circulation loop testing results, 163 B-6 Location of partial system test, 165 B-7 Photos of temporary phosphoric acid feed equipment, 165 B-8 Fact Sheet: Ne
34、w Treatment to Address Lead in Water, 166 B-9 Excerpts from DC Waters test sampling and response plan, 167 C-1 Geographic location of US participants by USEPA region, 174 C-2 Percentage of CWSs in SDWISFED versus percentage of survey respondents by USEPA region, 175 C-3 Geographic location of partic
35、ipants by Canadian province/territory, 175 C-4 Number of systems by population category, 176 C-5 Range of source water pH, 176 C-6 Range of source water alkalinity, 177 C-7 Range of source water DIC, 177 C-8 Number of systems practicing and not practicing corrosion control for Source #1, 178 C-9 Cor
36、rosion control treatment used for Source #1, 180 C-10 Percentile distribution plot of US 90th percentile lead levels, 180 C-11 Percentile distribution plot of US 90th percentile copper levels, 181 C-12 90th percentile lead levels as a function of pH, 182 C-13 90th percentile lead levels for systems
37、using phosphates, 182 C-14 90th percentile lead levels as a function of type of phosphate used, 183 C-15 Comparison of 90th percentile lead levels for systems practicing pH adjustment versus phosphates, 183 C-16 90th percentile copper levels as a function of pH, 184 C-17 90th percentile copper level
38、s for systems using phosphates, 184 C-18 Comparison of 90th percentile copper levels for systems practicing pH adjustment versus phosphates, 185 C-19 Percentile distribution of average lead and copper levels for Canadian respondents, 187 M58 book.indb 7 11/17/2010 4:24:29 PM Copyright 2011 American
39、Water Works Association. All Rights Reserved. This page intentionally blank. M58 book.indb 8 11/17/2010 4:24:30 PM Copyright 2011 American Water Works Association. All Rights Reserved. This page intentionally blank. ix Tables 1-1 Eight steps to implementing an effective corrosion control program, 1
40、1-2 Summary of potential copper corrosion issues, 5 2-1 Chapter 2 key points, 14 3-1 Chapter 3 key points, 32 3-2 Impact of coagulant changes on lead corrosion, 42 3-3 Suggested water quality monitoring parameters, 50 3-4 Assessment of common corrosion-related water quality problems, 54 4-1 Chapter
41、4 key points, 62 4-2 Corrosion properties of materials frequently used in water distribution systems, 63 4-3 Galvanic couples in the water industry that are dangerous, 70 4-4 Pipe wall linings, 72 4-5 Common corrosion control chemicals, 73 4-6 Treatment chemical water quality and corrosion control a
42、spects, 75 4-7 Chemical operational aspects, 79 4-8 Comparative cost of treatment chemicals, 93 4-9 Relative cost information, 93 4-10 Potential impact of treatment changes on corrosion control, 96 4-11 Potential secondary impacts, 98 4-12 Corrosion control technique selection criteria, 100 5-1 Chap
43、ter 5 key points, 104 5-2 Summary of coupon protocols used for distribution system corrosion measures, 118 5-3 Summary of EC corrosion assessment methodologies, 121 5-4 EC corrosion data analysis software, 122 6-1 Chapter 6 key points, 132 6-2 Example of distribution target levels for water quality
44、parameters routine monitoring during pilot testing, 139 6-3 Example of target and excursion levels for OCCTWQPs, 145 A-1 Summary of pH stability requirements, 150 A-2 Alkalinity increment as dictated by average alkalinity baseline value, 153 B-1 Key characteristics of the D.C. distribution system, 1
45、59 B-2 DC Water distribution system target levels, 171 C-1 Breakdown of survey responses, 174 C-2 Typical source water quality parametersutilities considering corrosion control, 178 C-3 Purpose for corrosion control at Canadian utilities with a corrosion control program, 179 C-4 Summary of sample ap
46、proaches by province/territory, 186 ix M58 book.indb 9 11/17/2010 4:24:30 PM Copyright 2011 American Water Works Association. All Rights Reserved. This page intentionally blank. M58 book.indb 10 11/17/2010 4:24:30 PM Copyright 2011 American Water Works Association. All Rights Reserved. This page int
47、entionally blank. Preface xi Volunteers from the Distribution System Water Quality Committee of the American Water Works Association (AWWA) have prepared this manual of practice. The need for a manual on corrosion assessment, monitoring, and control results from the increased focus on corrosion-rela
48、ted water quality and infrastructure impacts in drinking water dis- tribution systems. Considerable literature is available regarding the factors that influence corrosion in the distribution system. However, little practical guidance is available to pub- lic water systems regarding the design, imple
49、mentation, and maintenance of an effective corrosion control program. This manual seeks to provide that practical guidance. This manual helps readers understand the factors that influence corrosion, assess corrosion-related impacts, and develop a strategy to implement and maintain effective corrosion control in the water distribution system. The manual is organized in three main parts. Chapters 1 through 3 help the reader develop an understanding of the factors that influence corrosion and determine potential causes of corrosion in the distribu
