Dissolved Air Flotation For Water Clarification

553 Pages·2011·8.66 MB·English

by  James Edzwald

DISSOLVED AIR
FLOTATION
FOR WATER
CLARIFICATION
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DISSOLVED AIR
FLOTATION
FOR WATER
CLARIFICATION
James K. Edzwald, Ph.D.
Johannes Haarhoff, Ph.D.
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ISBN 978-0-07-174563-5
MHID 0-07-174563-7
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Dissolved Air Flotation for Water Clarification
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ABOUT THE AUTHORS
James K. Edzwald is Professor Emeritus in the Department of Civil and Environmental
Engineering at the University of Massachusetts, Amherst. He earned his B.S. and M.S.
degrees in Civil Engineering and Environmental Health Engineering at the University of
Maryland, and a Ph.D. in Water Resources Engineering at the University of North Carolina,
Chapel Hill. He also held faculty positions at the University of Missouri, Clarkson
University, and Rensselaer Polytechnic Institute. His research interests include water supply,
drinking water treatment, and aquatic chemistry. Dr. Edzwald has authored or coauthored
over 150 publications on water quality and treatment. He is the editor of the sixth edition of
Water Quality & Treatment: A Handbook on Drinking Water, published by AWWA and
McGraw-Hill. He received the 2004 A.P. Black Award from AWWA for his contributions in
water supply research and the 2009 Founders’ Award from the Association of Environmental
Engineering and Science Professors for his contributions to environmental engineering
education and practice. He is a registered professional engineer in New York.
Johannes Haarhoff is Professor in the Department of Civil Engineering Science at the
University of Johannesburg (UJ), South Africa. He earned an Honors B.Eng. in Civil
Engineering at the University of Stellenbosch, South Africa, followed by an M.Eng. in Water
Engineering at the same university. He spent eight years working in municipal engineering
and civil construction before enrolling at Iowa State University, where he earned a Ph.D. in
Sanitary Engineering. After a few years as a water treatment specialist at a prominent South
African consultancy, Dr. Haarhoff was appointed a Professor at the Rand Afrikaans
University (since 2005 the University of Johannesburg). He established the UJ Water
Research Group, which focuses on practical aspects of water supply and drinking water
treatment. He is a registered professional engineer in South Africa, a Fellow of the South
African Institution of Civil Engineering, and a Senior Fellow of the Water Institute of
Southern Africa.
Cover photo: Segaliud Water Treatment Plant (Sandakan, Sabah, East Malaysia). Photo
courtesy of Purac, Sweden.
CONTENTS
Preface
Acknowledgments
Chapter 1. Introduction
1-1 Types of Flotation Methods
1-2 Overview Description of DAF for Drinking Water Clarification
References
Chapter 2. A History of Dissolved Air Flotation
2-1 The Initial Use of Flotation for Mineral Separation
2-2 DAF Development for the Paper Industry
2-3 DAF Adapted for Industrial Wastewater Treatment
2-4 The Theoretical Basis for DAF is Consolidated
2-5 DAF for Potable Water Treatment in the 1960s
2-6 The Spread of DAF Since 1970
2-7 International DAF Conferences
2-8 The Application and Acceptance of DAF
References
Records of International Conferences
Chapter 3. Air Saturation
3-1 Air Requirements for DAF
3-2 The Principles of Air Saturation
3-3 Open-End Saturation
3-4 Dead-End Saturation
3-5 Saturator Efficiency
3-6 Air Flow and Energy Requirements
3-7 Design Example
References
Chapter 4. Air Precipitation
4-1 Distribution and Adjustment of Saturator Flow
4-2 Bubble Suspensions
4-3 Bubble Formation
4-4 Injection Nozzles
References
Chapter 5. Air Bubbles and Particles in Water
5-1 Air Bubbles in Water
5-2 Particles in Water
5-3 Particle-Bubble Interactions and Forces
References
Chapter 6. Pretreatment Coagulation and Flocculation
6-1 Introduction to Coagulation
6-2 Contaminants
6-3 Bulk Water Chemistry and Temperature
6-4 Rapid Mixing
6-5 Coagulation Chemistry and Mechanisms