Microbiological Aspects of BIOFILMS and DRINKING WATER - Chapter 1 ppt

About the Authors Preface Chapter 1 Water Supply, Treatment, and Distribution.... 103 Chapter 9 Methods of Sampling Biofilms in Potable Water .... 171 Chapter 11 Disinfection and Control

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BIOFILMS and DRINKING WATER

Microbiological Aspects

of

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SERIES EDITOR

RUSSELL H VREELAND

Titles in the Series

The Biology of Halophilic Bacteria

Russell H Vreeland and Lawrence Hochstein

The Microbiology of Deep-Sea Hydrothermal Vents

David M Karl

The Microbiology of Solid Waste

Anna C Palmisano

The Microbiology of the Terrestrial Subsurface

Penny S Amy and Dana L Haldeman

The Microbiology and Biogeochemistry of Hypersaline Environments

Aharon Oren

Microbiological Aspects of Biofilms and Drinking Water

Steven L Percival, James T Walker, and Paul R Hunter

The Microbiology of

EXTREME AND UNUSUAL

ENVIRONMENTS

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Boca Raton London New York Washington, D.C.

CRC Press

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This book contains information obtained from authentic and highly regarded sources Reprinted material

is quoted with permission, and sources are indicated A wide variety of references are listed Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use.

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Library of Congress Cataloging-in-Publication Data

ISBN 0-8493-0590-X (alk paper)

1 Biofilms 2 Drinking water Microbiology I Walker, James Thomas II Hunter, Paul

R III Title IV Series.

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About the Authors

Dr Steven Percival is qualified from the University of Leeds with a PhD in biology specilising in biofilmology His PhD involved looking at the developmentand consequences of biofilms in drinking water He also has an MSc in public healthand various other qualifications in microbiology Presently, Dr Percival is a seniorlecturer in microbiology at University College Chester and head of the MicrobiologyResearch Group Steven has a broad range of experiences in the problems, detection,and control of biofilms in the water and medical industries and has gained a largeamount of experience in microbiology and waterborne diseases as a result of this.His research at present involves looking at Helicobacter pylori, Aeromonas hydro- phila, and Mycobacterium avium intracellulare complex in biofilms and drinkingwater systems Other projects he is involved in include antibiotic and biocidalresistance, the effects of heavy metals on the attachment of pathogens to surfaces,biodeterioration, and microbially induced corrosion He has been involved in micro-biological consultancy for a number of companies, in particular the Ministry ofDefence Dr Percival is a member of various organisations including the Societyfor Microbiology, Society for Applied Microbiology, The International Biodeterio-ration Society, Biofilm Club, and the International Water Association He is thesecretary of the International Biodeterioration Society and microbiological advisor

micro-to the membership committee of the Institute of Biology

Dr Jimmy Walker obtained an HND in biology at Bellshill College, Scotlandbefore graduating in microbiology from the University of Aberdeen Jimmy under-took his PhD whilst working at CAMR, investigating biofilms in copper tube cor-rosion and the survival of Legionella pneumophila

Jimmy has a broad range of experience in the problems, detection, and control

of biofilms in the water and medical industries As a research microbiologist atCAMR, Dr Walker carries out projects on biofouling often involving category IIIpathogens such as E Coli 0157 He is an editorial board member of the International Biodeterioration & Biodegradation Journal and Anti-Corrosion Methods & Mate- rials Journal, and he has published over 40 scientific papers

Dr Walker is an external PhD examiner at the Robert Gordon’s University inAberdeen and an external supervisor at the University College Chester As well assitting on the committee of the Biofilm Club, he is also the vice president of theInternational Biodeterioration Society

Prof Paul Hunter qualified in medicine from Manchester University and thenwent on to specialise in medical microbiology He gained his MD for research intothe epidemiology of Candida infection Prof Hunter is a fellow of the Royal College

of Pathologists and a member of the Faculty of Public Health of the Royal College

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of Physicians He was appointed director of the Chester Public Health Laboratory

in 1988 and works as a consultant in medical microbiology, communicable diseasecontrol, and epidemiology He is also visiting professor in microbiology at UniversityCollege Chester He has had a continuing interest in water microbiology and water-borne disease for many years and has written Waterborne Disease: Epidemiology and Ecology and he has published over 100 papers in the scientific and medicalliterature Prof Hunter is chair of the PHLS Advisory Committee on Water and theEnvironment and serves on several other national and international committees andadvisory groups

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About the Authors

Preface

Chapter 1 Water Supply, Treatment, and Distribution 1

Chapter 2 Epidemiology 15

Chapter 3 Waterborne Diseases 29

Chapter 4 Risk Assessment 41

Chapter 5 Legislation and Water Quality 49

Chapter 6 Biofilm Development in General 61

Chapter 7 Biofilm Formation in Potable Water 85

Chapter 8 Microbes and Public Health Significance 103

Chapter 9 Methods of Sampling Biofilms in Potable Water 155

Chapter 10 Materials Used in the Transport of Potable Water with Special Reference to Stainless Steel and Corrosion 171

Chapter 11 Disinfection and Control of Biofilms in Potable Water 199

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After many years of studying microbiology, biofilms, and public health, it became

my ambition to produce a book on these three areas Having researched substantiallyinto the formation and development of biofilms, particularly in potable water, I felt

a book that could consolidate all the information on their public health significancewas needed This book provides a snapshot of public health and water with anappreciation of what a biofilm is and how well it presents a safe haven for pathogens,while factorizing unreported and reported water-related diseases

This book has been written with the help of friends, Dr Jimmy Walker andProfessor Paul Hunter, without whom areas of the book would have been difficult

to write The book is written with a large number of people in mind, but in particular,students, lecturers, researchers, and practitioners in water-related problems This text is an overview of the public health effects associated with potablewater and includes particular reference to the microbiological aspects relating to thedevelopment of biofilms The first five chapters focus on the state of the water supply

of the nation, highlighting historical developments and areas of concern Methodsthat could be employed to study the epidemiological spread of waterborne infectionsand methods which are used in surveillance and control of pathogenic microbes arereviewed Also included is a chapter on legislation and methods which are presentlyemployed for the detection of indicator microorganisms of public health importance

in potable water

Chapters 6 to 11 focus particularly on biofilm development within potable water,highlighting the public health threat from this Also included here is a very largeoverall review of the microbes of public health importance in potable water andbiofilms Methods used to detect biofilms can be found in Chapter 9 This by nomeans includes all the methods that can be used to study biofilms but rather itincorporates a large number of methods which have been shown to help in theanalysis Control of biofilms and the methods that are presently involved, includingboth conventional and biocidal treatments, are reviewed in the final chapter Theparticular control methods covered include chlorination, and the modes of action ofthis and other biocides are also documented We hope you enjoy reading this bookwhich will hopefully provide an aid to the study of biofilms in drinking water

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1 Water Supply, Treatment,

and Distribution

CONTENTS

1.1 Water Supply 1

1.2 A Short History of Water Supply and Treatment 2

1.3 Water Treatment Sources 3

1.3.1 Surface Water 3

1.3.2 Groundwater 4

1.4 Water Treatment 6

1.4.1 Pretreatment 6

1.4.2 Coagulation and Sedimentation 8

1.4.3 Filtration 9

1.4.4 Disinfection 9

1.5 Water Distribution 12

1.6 References 13

1.1 WATER SUPPLY

The ready availability of potable water is taken for granted by most people in the Western world Nevertheless, as will be seen throughout this book, the need for effective water extraction, treatment, and distribution remains as great now as it ever was To safeguard public health, potable water has to be free of pathogens and noxious chemicals It must also be pleasant to taste and have good appearance for human consumption Water companies have a responsibility to provide a continuous supply of wholesome water which is achievable through the collection, treatment, and, then, distribution of water

It was, however, not that long ago that safe clean water was not something that people in industrial cities could expect Even in today’s world, the problem of supplying safe water to many of the world’s population seems to be becoming beyond our ability to solve By 2025, one third of the world’s population is expected to suffer from chronic water shortages and more than 60% is likely to face some water-related problems It has also been estimated that the per capita supply of fresh, safe water for the next generation will be only one third of the supply available 30 years ago Although physiologically man can survive on just a few litres per day, the World Health Organization has suggested that people need 20 to 40 litres per day.1 The average daily consumption per person in the U.K is 150 litres, and in the U.S it ranges from 380 to 950 litres per person per day.2

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2 Microbiological Aspects of Biofilms and Drinking Water

In this chapter we shall briefly review the history of water treatment and bution technology before discussing in more detail current water treatment technol-ogy

distri-1.2 A SHORT HISTORY OF WATER SUPPLY AND TREATMENT

Although man has used irrigation for agricultural purposes since prehistoric times,

it was not until ancient Egyptian and Babylonian civilisations that large-scale gation systems of dams and canals were developed.2 Although their primary purposewas agricultural, individuals undoubtedly used them for their own supply of drinkingwater The first civilisation to practice water treatment on a large scale was theRomans In addition to constructing huge aqueducts to carry clean water from themountains into the city, they also built settling basins and filters to improve theclarity of the water With the decline of the Roman Empire, people largely reverted

irri-to local wells, springs, and streams

The first pump-powered water distribution system was built in 1562 in London.This pumped water from the Thames into a reservoir which then distributed thewater locally through lead pipes No particular treatment was applied

The main impetus for the next stage in the development of water treatment wasthe cholera and typhoid epidemics which ravaged Europe during the 19th century.The high mortality from these epidemics drove the sanitary movement in the U.K.which put forward the conviction that health and disease were functions of socialconditions This movement led to the 1842 publication of the Report of an Inquiry into the Sanitary Condition of the Labouring Population of Great Britain by EdwinChadwick This report proposed that ill health was owing to overcrowding, inade-quate waste disposal, polluted water, and bad diet Many would date modern publichealth to the publication of this report

It was also around this time when the germ theory of disease started to gainground Ironically, many within the sanitary movement had serious objections to thegerm theory of disease We now know that much of what they were recommendingworked because of the impact of their suggestions for healthy living on the trans-mission of microbial pathogens

Further support for the importance of clean water came from John Snow(1813–1858), who wrote his account, On the Mode of Communication of Cholera

in 1849 This suggested a correlation between cholera and water supplies In 1854,Snow was able to demonstrate the link between the Broad Street pump and manyfatal cases of cholera In doing so, he simultaneously proved that water could carrydisease and established the science of epidemiology

In 1846, the U.K Parliament passed the Liverpool Sanitary Act which gave thecity council the power to appoint a medical officer, borough engineer, and inspector

of nuisances Two years later, in 1848, The National Health Act was passed Thisact created a general board of health and allowed for the setting up of local boards

of health to deal with various matters of environmental cleanliness including watersupplies This act was later replaced by the Public Health Act in 1875.3 It was fromthis time that developments in water treatment progressed apace

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Water Supply, Treatment, and Distribution 3

1.3 WATER TREATMENT SOURCES

In order to provide a continuous supply of potable water, the most important factor

is access to source water of an acceptable quality In the U.K., the supply of water

is generally obtained from surface water which accounts for 70% of available water,and groundwater which accounts for 30% of available water Whilst surface water

is generally easier to both locate and extract than groundwater, it is readily affected

by the surrounding environment resulting in the need for greater treatment.4 tion and treatment requirements are very different for surface and groundwater andthey will be considered separately

Surface water includes water from lakes, ponds, rivers, and streams Ultimately, allsurface water falls as rain Although some of this rain falls directly onto the waterbody, most falls onto land and then gains access to the water body as runoff Inmany lowland waters, much of the water body is filled from other sources such aswastewater treatment plant discharge

The quality of surface water in upland areas differs substantially from that inlowland areas Lowland waters are usually more turbid, more nutrient rich, andcontain various natural and man-made pollutants The quality of surface water canalso show large temporal variations in water quality owing to factors such as waterflow, local rainfall, temperature, and changing industrial activity

Where rain falls onto impervious rocks, it will flow over the ground or throughthe soil layer directly into streams or rivers Such water will have a relatively lowmineral content and be quite soft It can, however, pick up organic and inorganiccontaminants This is most obvious in water from peaty areas which can be highlycoloured If water falls onto porous rock such as chalk or limestone, much of it maysoak into the ground Such water may remain as groundwater, or it may return tothe surface as springwater, or directly enter a river from ground flow Surface water

in these more porous areas is more mineralised and harder, but it generally has fewercontaminants and is clearer Figure 1.1 shows the various routes through whichrainwater can enter a water body

Upland water usually requires very little treatment There are many communitiesthat take such water abstracted from naturally formed or dammed lakes Typically,water treatment may include some form of coarse screening with or without filtrationand little or no chlorination before being distributed to consumers’ homes The mainrisk to such supplies comes from agricultural activity in the river’s watershed Withchlorinated supplies, the main risk is parasitic disease such as giardiasis and cryptospo-ridiosis With un-chlorinated supplies there is also a risk of bacterial pathogens, mostcommonly, Campylobacter.5 If there is much human habitation above the water extrac-tion point, the range of potential pathogens increases considerably Control of this riskrelies on managing human and agricultural activity in the watershed

As already mentioned, lowland surface water is usually much more pollutedthan upland water and so requires considerably more treatment Sources of pollutionfor lowland waters include discharges from wastewater treatment plants, industrialsites, and runoff from urban areas as well as agricultural land Because lowland

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