LECTURE NOTES Degree Program For Environmental Health Science Students Water Supply II Negesse Dibissa Worku Tefera Hawassa University In collaboration with the Ethiopia Public Health Training Initiative, The Carter Center, the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education December 2006 Funded under USAID Cooperative Agreement No. 663-A-00-00-0358-00. Produced in collaboration with the Ethiopia Public Health Training Initiative, The Carter Center, the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education. Important Guidelines for Printing and Photocopying Limited permission is granted free of charge to print or photocopy all pages of this publication for educational, not-for-profit use by health care workers, students or faculty. All copies must retain all author credits and copyright notices included in the original document. Under no circumstances is it permissible to sell or distribute on a commercial basis, or to claim authorship of, copies of material reproduced from this publication. ©2006 by Negesse Dibissa, Worku Tefera All rights reserved. Except as expressly provided above, no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission of the author or authors. This material is intended for educational use only by practicing health care workers or students and faculty in a health care field. PREFACE The principal risk associated with community water supply is from waterborne diseases related to fecal, toxic chemical and mineral substance contamination as a result of natural, human and animal activities. When people consume water from a contaminated source, they will be exposed to infectious and other related diseases, risking possible death and disability. Therefore, it is important to make the water safe for human consumption through the utilization of different methods of protection and treatment. For this reason, a lecture note is developed for environmental health students on how to treat water at household, small scale and large scale levels, to make the water safe for human consumption. The lecture note also includes information on water quality control for the assessment of hygienic quality of the drinking water using physical, chemical and bacteriological analysis and the principle of water pumps to lift and distribute water from shallow and deep wells for individual and community utilization. As the trainings at higher institutions have been upgraded to a degree level, this lecture note is developed as an upgrade version of the earlier one though some changes on the chapters, contents and sequences. A chapter, “Water Supply in Disaster Management” is also incorporated in this upgraded i lecture note. In this lecture note, too, each chapter has its own learning objectives, review questions, and note for the teachers (wherever deemed relevant). Both Metric and English system of measurements were used. However, the conversion factors are given on the annex. ii ACKNOWLEDGMENT We express our sincere thanks to Professor Dennis Carlson, Resident Technical Advisor, and Resident Resource Team at The Carter Center: Dr. Hailu Yeneneh, Ato Aklilu Mulgeta, Ato Assefa Bulcha, W/t Meseret Tsegaw, and W/t Mahlet Tilahun, for their encouraging and honorable advice in organizing teaching material development. We are grateful to The Carter Center for its overall financial and material support for facilitating the lecture note preparation process. We are also thankful to intra- and inter-institutional reviewers: Ato Sileshi Behailu and Getachew Redaei; and Dr. Mengesha Admassu, Ato Tesfaye Gobena, Ato Fantahun Wassie, and Ato Birhanu Zeleke, respectively, for giving valuable comments, contributions, and suggestions for upgrading this lecture note. We are very grateful to national reviewers, Ato Gebre- Emanuel Teka, Associate professor (Retired), and Dr. Abera Kumie, Assistant Professor, MF, AAU for their critical comments and suggestions made during the review. We are also indebted to thank Ato Dejene Hailu, Dr. Eshetu Wassie, and Ato Biruck Desalegn for facilitating the reviewing process. iii Finally, we wish to thank W/t Meaza Teferi, for computer typing the original material. iv TABLE OF CONTENTS PREFACE .................................................................................i ACKNOWLEDGMENT ........................................................... iii CONTENTS .............................................................................v LIST OF TABLES ................................................................. viii LIST OF FIGURES ................................................................. ix ABBREVIATIONS AND ACRONYMS ................................... xi CHAPTER ONE INTRODUCTION ..................................................................... 1 Learning Objectives ............................................................ 1 1.1 Existing Problems of Water Supply .............................. 1 Review Questions ............................................................... 7 CHAPTER TWO WATER QUANTITY AND QUALITY ASSESSMENT ............ 8 Learning Objectives ............................................................ 8 2.1 Introduction ................................................................... 9 2.2 Water Quality Analysis ................................................ 17 Review Questions ............................................................. 34 CHAPTER THREE WATER TREATMENT .......................................................... 36 Learning Objectives .......................................................... 36 3.1 Introduction ................................................................. 36 3.2 Water Treatment on Small Scale ................................ 37 v 3.3 Design Principles and Unit Processes of Conventional (Large Scale) Water Treatment ........................................ 52 3.4 Supplementary water treatment ............................... 133 Review Questions ........................................................... 176 CHAPTER FOUR SAMPLING TECHNIQUES AND PROCEDURES ............. 179 Learning Objectives ........................................................ 179 4.1 Introduction ............................................................... 179 4.2 Principles of Water Sampling and Analysis .............. 180 4.3 Types of Sampling and Sampling Techniques ......... 180 4.3 Frequency of Sampling ............................................. 186 4.4 Water Analysis .......................................................... 188 4.5 Interpretation of Results ............................................ 194 Review Questions ........................................................... 197 CHAPTER FIVE WATER SURVEILLANCE .................................................. 198 Learning Objectives ........................................................ 198 5.1 Introduction ............................................................... 198 5.2 Sanitary Survey ........................................................ 199 Review Questions ........................................................... 210 CHAPTER SIX WATER DISTRIBUTION AND HYDRAULICS ................... 211 Learning Objectives ........................................................ 211 6.1 Introduction ............................................................... 211 6.2 Water Distribution ..................................................... 227 vi 6.3 Hydraulics and Its Applications to Drinking Water Supplies .......................................................................... 234 Review Questions ........................................................... 266 CHAPTER SEVEN WATER SUPPLY IN DISASTER MANAGEMENT ............ 268 Learning Objectives ........................................................ 268 7.1 Introduction ............................................................... 268 7.2 Water Supply Activities ............................................. 270 7.3 Water in Camps of Displaced People ....................... 274 7.4 Conclusion ................................................................ 300 Review Questions ........................................................... 302 Glossary ............................................................................. 303 Reference ........................................................................... 307 Annexes ............................................................................. 312 Annex I. Water Quality Standards .................................. 312 Annex II Unit conversions ............................................... 314 vii LIST OF TABLES Table 3.1 Classification of Water by Concentration of Coliform Bacteria and Treatment Required .............................. 75 Table 3.2 Availability, forms of chlorine, and its compounds 111 Table 3.3 Chlorine residual for effective disinfection of filtered water ....................................................................... 117 Table 3.4 Approximate volume of 10% alum solution (ml) to be added in 40 liters of test water to obtain the acceptable limit (1.0mg F/l) of fluoride .................... 141 Table 3.5 Removal of dissolved iron ....................................... 165 Table 4.1 Frequency of sampling for unchlorinated water supplies ................................................................... 193 Table 4.2 Guidelines for bacteriological