Microbiology of Drinking Water E-Book

Gabriel Bitton

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 581

Veröffentlichungsjahr: 2014

Beschreibung

Microbiology of Drinking Water Production and Distribution addresses the public health aspects of drinking water treatment and distribution. It explains the different water treatment processes, such as pretreatment, coagulation, flocculation, sedimentation, filtration, disinfection, and their impacts on waterborne microbial pathogens and parasites. Drinking water quality may be degraded in water distribution systems--microorganisms form biofilms within distribution systems that allow them to flourish. Various methodologies have been proposed to assess the bacterial growth potential in water distribution systems. Microbiology of Drinking Water Production and Distribution also places drinking water quality and public health issues in context; it addresses the effect of bioterrorism on drinking water safety, particularly safeguards that are in place to protect consumers against the microbial agents involved. In addition, the text delves into research on drinking water quality in developing countries and the low-cost treatment technologies that could save lives. The text also examines the microbiological water quality of bottled water, often misunderstood by the public at large.

Leseprobe

MICROBIOLOGY OF DRINKING WATER PRODUCTION AND DISTRIBUTION

GABRIEL BITTON

Department of Environmental Engineering Sciences

Engineering School of Sustainable Infrastructure & Environment

University of Florida, Gainesville, Florida, USA

Copyright © 2014 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data has been applied for.

ISBN: 978-1-1187-4392-8 (cloth)

Cover image: Water drops © AndrewJohnson, Bubbles in a water glass © Sergey_Peterman

To Benjamin Noah and to all my family across the oceans.

This book is dedicated to all the children around the world who do not have access to safe drinking water.

CONTENTS

PREFACE

1 MICROBIAL CONTAMINANTS IN DRINKING WATER

1.1 Introduction

1.2 Transmission Routes of Pathogens and Parasites

1.3 Major Pathogens and Parasites of Health Concern in Drinking Water

Web Resources

Further Reading

2 MICROBIOLOGICAL ASPECTS OF DRINKING WATER TREATMENT

2.1 Introduction

2.2 Worldwide Concern Over Drinking Water Safety

2.3 Microbiological Quality of Source Water

2.4 Overview of Processes Involved in Drinking Water Treatment Plants

2.5 Process Microbiology and Fate of Pathogens and Parasites in Water Treatment Plants

2.6 Waste Residuals from Water Treatment Plants

2.7 Drinking Water Quality at the Consumer's Tap

Web Resources

Further Reading

3 DRINKING WATER DISINFECTION

3.1 Introduction

3.2 Chlorine

3.3 Chlorine Dioxide

3.4 Ozone

3.5 Ultraviolet Light

3.6 Use of Photocatalysts in Water Disinfection

3.7 Physical Removal/Inactivation of Microbial Pathogens

Web Resources

Further Reading

4 DRINKING WATER DISTRIBUTION SYSTEMS: BIOFILM MICROBIOLOGY

4.1 Introduction

4.2 Biofilm Development in WDSs

4.3 Growh of Pathogens and Other Microorganisms in WDSs

4.4 Some Advantages and Disadvantages of Biofilms in Drinking Water Treatment and Distribution

4.5 Biofilm Control and Prevention

Web Resources

Further Reading

5 ESTHETIC AND OTHER CONCERNS ASSOCIATED WITH DRINKING WATER TREATMENT AND DISTRIBUTION

5.1 Introduction

5.2 Taste and Odor Problems in Drinking Water Treatment Plants

5.3 Algae and Cyanobacteria

5.4 Fungi

5.5 Actinomycetes

5.6 Protozoa

5.7 Invertebrates

5.8 Endotoxins

5.9 Iron, Manganese, and Sulfur Bacteria

5.10 Nitrifying Bacteria in Water Distribution Systems

Web Resources

Further Reading

6 BIOLOGICAL TREATMENT AND BIOSTABILITY OF DRINKING WATER

6.1 Introduction

6.2 Biological Treatment of Drinking Water

6.3 Assessment of Biostability of Drinking Water

Web Resources

Further Reading

7 BIOTERRORISM AND DRINKING WATER SAFETY

7.1 Introduction

7.2 Early History of Biological Warfare

7.3 BW Microbial Agents and Biotoxins

7.4 Deliberate Contamination of Water Supplies with BW Agents or Biotoxins

7.5 Early Warning Systems for Assessing the Contamination of Source Waters or Water Distribution Systems

7.6 Protection of Drinking Water Supplies

7.7 Disinfection Of BW-Contaminated Drinking Water

Web Resources

Further Reading

8 WATER TREATMENT TECHNOLOGIES FOR DEVELOPING COUNTRIES

8.1 Introduction: Water for a Thirsty Planet

8.2 Some Statistics of Waterborne Diseases in Developing Countries

8.3 Some HWT Methods or Technologies in Use in Developing Countries

8.4 Personal Portable Water Treatment Systems for Travelers and Hikers

Web Resources

Further Reading

9 BOTTLED WATER MICROBIOLOGY

9.1 Introduction

9.2 Sources and Categories of Bottled Water

9.3 Bottled Water Microorganisms

9.4 Regulations Concerning Bottled Water

Web Resources

Further Reading

10 INTRODUCTION TO MICROBIAL RISK ASSESSMENT FOR DRINKING WATER

10.1 Health-Based Targets for Drinking Water

10.2 Quantitative Microbial Risk Assessment (QMRA)

10.3 Some Examples of Use of Risk Assessment to Assess the Risk of Infection or Disease From Exposure to Microbial Pathogens

Web Resources

Further Reading

REFERENCES

INDEX

END USER LICENSE AGREEMENT

List of Tables

Chapter 1

Table 1.1

Table 1.2

Table 1.3

Table 1.4

Table 1.5

Table 1.6

Table 1.7

Table 1.8

Table 1.9

Table 1.10

Chapter 2

Table 2.1

Table 2.2

Table 2.3

Table 2.4

Chapter 3

Table 3.1

Table 3.2

Table 3.3

Chapter 4

Table 4.1

Table 4.2

Chapter 5

Table 5.1

Table 5.2

Chapter 6

Table 6.1

Chapter 7

Table 7.1

Table 7.2

Table 7.3

Table 7.4

Table 7.5

Table 7.6

Chapter 8

Table 8.1

Table 8.2

Table 8.3

Table 8.4

Table 8.5

Table 8.6

Chapter 9

Table 9.1

Chapter 10

Table 10.1

Table 10.2

Table 10.3

Table 10.4

Guide

Cover

Table of Contents

Preface

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PREFACE

In industrial countries, we take safe drinking water for granted. Due to an increase in world population, the microbiological safety of drinking water is becoming a worldwide concern. Following a meeting of drinking water experts in 1995, it was predicted that water safety will be a major concern in the 21st century (Ford and Colwell, 1996). Concerns have been raised over the emergence of antibiotic resistance and chlorine-resistant microorganisms such as Cryptosporidium. Consequently, the largest documented waterborne cryptosporidiosis outbreak occurred in 1993 in Milwaukee, Wisconsin, where 403,000 people became ill, resulting in 4400 hospitalized patients and 54 deaths. Furthermore, aging populations in developed countries and increasing use of immunosuppressive drugs have led to decreased immunity to waterborne pathogens and parasites. The problems are more serious in developing countries who suffer from unsafe drinking water and poor sanitation, and where children are, unfortunately, the main victims of infectious and parasitic diseases.

The long-term effects of chemical toxicants in drinking water have received much attention by investigators and, comparatively, less efforts have been devoted to the microbiological safety of this precious resource.

This book is divided into 10 chapters. The first chapter introduces the reader to the topic of microbial pathogens and parasites of concern in drinking water safety. Chapter 2 deals with the microbiology of the treatment processes involved in conventional water treatment plants. Advances in drinking water research followed by the establishment of multiple barriers against microbial pathogens and parasites have significantly increased the safety of the water we drink daily. This multiple-barrier system includes source water protection, reliable water treatment (pretreatment, coagulation, flocculation, sedimentation, filtration, disinfection, water softening, membrane filtration, activated carbon treatment, and the potential use of nanotechnology for water purification). Household water treatment processes via the use of point-of-use (POU) devices are also included in this chapter. Chapter 3 discusses the disinfection step that is an essential and final barrier against human exposure to disease-causing pathogenic microorganisms, including viruses, bacteria, and protozoan parasites. Disinfection of drinking water is probably the most significant preventive measure in human history. Many waterborne outbreaks are attributed to the degradation of water quality in water distribution systems (WDS) through cross-connections, main breaks, back siphonage, or negative pressure events. The main topic covered in Chapter 4 is biofilm microbiology with emphasis on biofilm formation and the factors involved in its development in water distribution pipes. The fate of pathogens (e.g., nontubercular mycobacteria, Legionella, protozoan parasites, enteric viruses, and opportunistic pathogens in general) is also covered. Chapter 5 covers other microbiological topics of concern in WDS. These topics include taste and odor problems, cyanotoxins produced by cyanobacteria, fungi, protozoa with emphasis on free living amoebas, microinvertebrates, iron and manganese bacteria, and the occurrence of nitrifying bacteria. Chapter 6 deals with the biotreatment and biostability of drinking water and covers the various methods used to assess biostability of drinking water. Drinking water safety can be compromised by the deliberate or accidental contamination of drinking water resources. Chapter 7 covers the major biowarfare microbial agents and biotoxins that could be used to deliberately contaminate drinking water. An estimated 1.1 billion of the world's population does not have access to safe clean water, and approximately 2.6 billion people lack improved sanitation. As a result, approximately 2.2 million people die each year from waterborne diseases. The World Health Organization estimates that endemic diarrhea accounts for 17% of all deaths among children less than 5 years of age. Chapter 8 covers the major treatment technologies for improving the quality of drinking water in developing countries. Chapter 9 addresses the topic of bottled water microbiology. Although bottled water is a useful resource in emergency situations, its quality may sometimes be contaminated via introduction of microbial pathogens at the source or during bottling. Chapter 10 describes the steps involved in quantitative microbial risk assessment (QMRA) and gives examples of the use of risk assessment to estimate the risk of exposure to bacterial, viral, and protozoan pathogens and predict the burden of waterborne diseases on a given community.

This book can serve as a textbook for courses on drinking water microbiology and would be useful in other courses in environmental engineering programs. Due to the author's extensive review of the literature pertaining to drinking water microbiology, this book can also serve as a reference text for engineers and scientists interested in the interface between public health microbiology and drinking water treatment and distribution.

I am grateful to Nancy, Julie, Thomas, Natalie, Jonathan, Ari-Gabriel, Benjamin Noah, my family across the globe, and my close friends and colleagues for their enthusiastic support for this project.

GABRIEL BITTON Gainesville, FL April 18, 2014

1MICROBIAL CONTAMINANTS IN DRINKING WATER

1.1 INTRODUCTION

In water treatment plants, the goal is to produce pathogen- and parasite-free drinking water, not necessarily sterile water. There are, however, several sources of contamination in a potable water system (Percival et al., 2000):

Drinking water source (see Chapter 2).

Inadequate treatment in the water treatment plant.

Water distribution system (WDS): Treated water quality may deteriorate in the distribution system. Pathogens and parasites may be introduced into treated water through cracks in the water pipes, back-siphonage or cross-contamination.

Biofilm development which may alter water quality.

This chapter surveys the major microbial pathogens and parasites which may contaminate drinking water.

1.2 TRANSMISSION ROUTES OF PATHOGENS AND PARASITES

Transmission involves the transport of an infectious agent from the reservoir to a host. It is the most important link in the chain of infection. Pathogens can be transmitted from the reservoir to a susceptible host by various routes. The transmission pathways of water-related pathogens are summarized in Figure 1.1 (WHO, 2011c).

Figure 1.1 Transmission pathways for water-related pathogens and parasites. Adapted from WHO (2011c). Guidelines for Drinking-Water Quality. 4th Ed. World Health Organization, Geneva, Switzerland.

1.2.1 Person-to-Person Transmission

The most common route of transmission of infectious agents is from person to person. Examples of direct contact transmission are the sexually transmitted diseases such as syphilis, gonorrhea, herpes, or acquired immunodeficiency syndrome (AIDS). Coughing and sneezing discharge very small droplets containing pathogens within a few feet of the host (droplet infection).

1.2.2 Waterborne Transmission

Water is essential to life on Planet Earth. Humans generally consume from 2 to 4 L water/day. The composition of drinking water has positive (e.g., iron, fluoride) and, sometimes, negative effects on human health because it may contain microbiological, chemical, and radiological contaminants. When contaminated with human and animal wastes, water contributes to (Mintz et al., 2001)