Microbial Quality of Water Supply in Distribution Systems

513 Pages·1996·89.715 MB·\513

by  Edwin E. Geldreich (Author)

Microbial Quality

of Water Supply in

Distribution Systems

Edwin E. Geldreich
Senior Research Microbiologist

United States Environmental Protection Agency

Drinking Water Research Division

Cincinnati, Ohio

LEWIS PUBLISHERS

Boca Ratan London New York Washington, D.C.
Library o f C ongress Cataloging-in-Publication D ata
Geldreich, Edwin E.
Microbial quality of water supply in distribution systems I Edwin
E. Geldreich.
p. cm.
Includes bibliographical references and index.
ISBN 1-56670-194-5 (alk. paper)
1. Water--Microbiology. 2. Water quality--Management. I. Title.
TD384.G45 1996
628.1 '62--dc20 95-37894
CIP
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Preface
Why a book on the microbial quality of water in distribution systems?
Simply because there is a need to better understand the problems hidden in
the pipe network buried under streets that may become a utility nightmare
when there is noncompliance with drinking water regulations or when a water­
borne disease crisis occurs.
These problems are not new, having been well hidden for years in disbelief
by management of some utilities that water quality could degrade upon passage
through the network of pipes, storage reservoirs, and standpipes. Engineering
textbooks and operator confidence in the ultimate power of a chlorine residual
to inactivate organisms of public health significance was unshaken. When
coliforms were reported from samples taken on the distribution system, the
immediate reaction by some operators was to discredit the sample as being
contaminated during collection or to reject the analysis as being a laboratory
error.
This attitude began to change during the 1970s with the intensification of
laboratory certification at the state level by the federal mandate to evaluate
laboratory performance and adherence to appropriate methods specified in
current editions of Standard Methods for Examination of W ater and Waste­
water. In turn, state programs were created to take this evaluation process to
the local utility, county, and private laboratories involved in water supply
monitoring. More intense appraisal of sample collection techniques, expanded
verification procedures for coliform-positive samples, and regulation require­
ments to repeat sample analyses at sites of coliform occurrence had done much
to strengthen the realization that coliform bacteria may co-exist with chlorine
residuals under a specific set of circumstances.
As these summer time coliform regrowth occurrences became more obvi­
ous, utilities were forced to try drastic measures in the hope of extinguishing
the microbial nightmare. One utility actually drained the entire supply of public
water from the system over a weekend in an effort to clean the pipe network
of these colonizations. This drastic action provided only a temporary measure
of success. Other systems elevated the chlorine residuals to as much as 5 mg/1
of free chlorine for brief periods of time. This action brought the system back
into compliance, but as soon as step wise drops in applied chlorine were begun,
coliform-positive samples began to appear again. Some treatment operators
began to apply various corrosion inhibitor additives only to find that somehow
things got worse, not better.
All of these events led the EPA Drinking Water Research Division to begin
an extensive research program to study the problem, identify the factors that
were key to microbial growth, and work with universities and the water utility
industry to study various factors in the field. Over the past 20 years many of
the issues have been identified, including composition of pipe biofilms, their
habitats in pipe sediments and tubercles, their nutrient base for survival, the
protective factors that shield them from disinfection contact, and some treat­
ment measures that appear to have a degree of success in specific instances.
Much of this state of knowledge appears in this book, yet much still remains
to be learned about the public health significance of biofilms, ecological
progression of a biofilm community, detecting areas of biofilm activity,
approach to successful preventive maintenance, and alternative treatment
regimes for an aggressive biofilm progression in the distribution system. Hope­
fully, the book will stimulate other scientists, engineers, and operators to work
on this aspect of drinking water microbiology and resolve the issue in the next
decade.
Edwin E. Geldreich
The Author
Edwin E. Geldreich, with more than 46 years of
research experience, has directed investigations into
the microbiology of water supply sources, treatment
processes, methods development, criteria, and stan­
dards. He has also been a frequent microbiology
consultant for World Health on projects in Europe
and South America involving water supply, fresh
water pollution, and recreational water and coastal
water quality. A member of American Water Works
Association (AWWA), American Society for Micro­
biology, and the International Association on Water
Pollution Research, Geldreich has received the Kim­
ble Methodology Research Award, the U.S. Environmental Protection Agency
silver and bronze medals, AWWA's Research Award, and the 1989 Abel Wol­
man Award of Excellence and was the 1991 Alien Hazen Lecturer to the New
England Water Works Association. He has also been a Fellow in the American
Academy of Microbiology for many years. As author of approximately 100
research papers and two books, his work has been published in many peer
review journals, including the Journal of the American Water Works Associ­
ation, Applied and Environmental Microbiology, and Water Pollution
Research.
Current interest during the past 20 years has focused on treatment barriers
and microbial problems in water supply distribution systems, their cause and
control. More than 30 utilities have invited Geldreich's participation in inves­
tigating coliform problems in their distribution systems. Activities have
included an investigation into the waterborne outbreaks at Cabool and Gideon,
Missouri, an investigation, at the request of the Peruvian Ministry of Health,
into their cholera outbreak for a water supply connection, and involvement in
an international conference urging water supply disinfection within the Latin
American and Caribbean community of nations to combat further waterborne
pathogen invasion.
Special Acknowledgments
In the development of the text it quickly became evident that visual aids
would be essential in demonstrating problems from the hidden environment
of the pipe network. A search was made to gather photographs and drawings
that could illustrate the issues on water quality degradation. I am grateful for
some of the pipe photographs supplied by colleagues in the field. Many of the
drawings, figures, and tables were the creation of Richard C. Findsen, artist,
Steve C. Waltrip, graphics expert, and Nancy T. Frazier, graphics assistant,
who volunteered their professional services and provided suggestions on the
selection of enhanced graphics for this book.
Table of Contents
Chapter 1
Characterizing the Distribution System: Microbial Issues ............................. 1

Chapter 2
Creating Microbial Quality in Drinking Water ............................................. 39

Chapter 3
Biological Profiles in Drinking Water ......................................................... 103

Chapter 4
Biofilms in Water Distribution Systems ...................................................... 159

Chapter 5
Characterizing Microbial Quality of Water Supply .................................... 215

Chapter 6
Monitoring Strategies to Characterize Water Quality ................................. 257

Chapter 7
Microbial Breakthroughs in Changing Source, Treatment,

or Supply Parameters ................................................................................... 311

Chapter 8
Waterbome Pathogen Invasions: A Case for Water Quality

Protection in Distribution ............................................................................ 359

Chapter 9
Responses to Microbial Quality Changes in Water

Supply Distribution ...................................................................................... 411

Chapter 10
Public Awareness of Water Quality Problems ............................................. 447

Appendix . .................................................................................................... 481

Index ............................................................................................................ 485
This book is dedicated to my wife Detta,

who provided much encouragement to

complete my improbable dream

of a book on this subject.
1
Searching for cause/effect. CHAPTER
Characterizing the Distribution System:
Microbial Issues
CONTENTS
Introduction ...................................................................................................... 2

Distribution System Habitats ........................................................................... 3

Pipes, Valves, and Fire Hydrants ................................................................ 3

Pipe Materials ......................................................................................... 6

Gaskets, Sealants, and Lubricants .......................................................... 8

Water Supply Storage ................................................................................. 9

Microbial Considerations ..................................................................... 10

Distribution Water Temperature Trends .................................................... 12

Water Supply Transient Time ........................................................................ 13

Supply and De1nand .................................................................................. 13

Operational Factors ........................................................................................ 14

Protective Protocol for Pipe Work ............................................................ 14

Cross-Connections and Back-Siphonage .................................................. 16

Flushing and Cleaning Pipe Networks ..................................................... 17

Corrosion Control ..................................................................................... 20

Internal Corrosion ................................................................................ 20

External Conosion ............................................................................... 21

Biologically Mediated Corrosion ......................................................... 22

Corrosion Treatment ............................................................................. 27

Pass-Through Heat Pumps ........................................................................ 30