HANDBOOK OF WATER AND WASTEWATER TREATMENT TECHNOLOGIES pps

HANDBOOK OF WATER AND

WASTEWATER TREATMENT

TECHNOLOGIES

Nicholas P. Cheremisinoff, Ph.D.

N&P Limited

P-- EINEMANN

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Copyright 0 2002 by Butterworth-Heinemann

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CONTENTS

Preface, vii

In Memory, ix

About the Author, x

Foreword, xi

Chapter 1. An Overview of Water and Wastewater Treatment, 1

Introduction, 1

What We Mean by Water F’urification, 4

The Clean Water Act, 26

Introducing the Physical Treatment Methods, 33

Introducing Chemical Treatment, 37

Energy Intensive Treatment Technologies, 40

Water Treatment in General, 42

Some General Comments, 56

List of Abbreviations Used in this Chapter, 57

Recommended Resources for the Reader, 58

Questions for Thinking and Discussing, 60

Chapter 2. What Filtration Is All About, 62

Introduction, 62

Terminology and Governing Equations, 63

Filtration Dynamics, 72

Wastewater Treatment Applications, 78

Key Words, 81

Nomenclature, 86

Recommended Resources for the Reader, 87

Questions for Thinking and Discussing, 89

Chapter 3. Chemical Additives that Enhance Filtration, 91

Introduction, 91

Aluminum Based Chemical Additive Compounds, 91

Iron-Based Compounds, 97

Lime, 101

SodaAsh, 104

Liquid Caustic Soda, 105

Filter Aids, 106

iii

Recommended Resources for the Reader, 120

Questions for Thinking and Discussing, 122

Chapter 4. Selecting the Right Filter Media, 123

Introduction, 123

Types of Filter Media to Choose From, 123

Rigid Filter Media, 132

General Properties of Loose and Granular Media, 142

Filter Media Selection Criteria, 148

Recommended Resources for the Reader, 152

Questions for Thinking and Discussing, 155

Chapter 5. What Pressure- and Cake-Filtration Are All About, 157

Introduction, 157

Constant Pressure Differential Filtration, 158

Constant-Rate Filtration, 168

Variable-Rate and -Pressure Filtration, 170

Constant-Pressure and -Rate Filtration, 172

Filter-Medium Filtration Formulas, 173

Cake Filtration Equipment, 184

Nomenclature, 213

Recommended Resources for the Reader, 214

Questions for Thinking and Discussing, 217

Chapter 6. Cartridge and Other Filters Worth Mentioning, 224

Introduction, 224

Cartridge Filters, 224

The Tilting Pan Filter, 228

The Table Filter, 23 1

Questions for Thinking and Discussing, 233

Chapter 7. What Sand Filtration is All About, 235

Introduction, 235

Water Treatment Plant Operations, 236

Granular Media Filtration, 243

Let’s Take a Closer Look at Sand Filters, 247

Slow Sand Filtration, 256

Rapid Sand Filtration, 257

Chemical Mixing and Solids Contact Processes, 260

Recommended Resources for the Reader, 265

iv

Questions for Thinking and Discussing, 266

Chapter 8. Sedimentation, Clarification, Flotation, and Coalescence, 268

Introduction, 268

Let’s Look at How a Single Particle Behaves in a Suspension, 269

Gravity Sedimentation, 275

The Sedimentation Process in Greater Detail, 282

A Closer Look at Mechanical Clarification Process and the Chemistry of

Clarification, 305

Rectangular Sedimentation Tanks, 315

Air Flotation Systems, 317

Separation Using Coalescers, 323

Nomenclature, 326

Recommended Resources for the Reader, 328

Questions for Thinking and Discussing, 331

Chapter 9. Membrane Separation Technologies, 335

Introduction, 335

An Overview of Membrane Processes, 336

What Electrodialysis Is, 339

What Ultrafiltration Is, 344

What Microfiltration and Nanofiltration Are, 354

What Reverse Osmosis Is, 360

Recommended Resources for the Reader, 367

Questions for Thinking and Discussing, 370

Chapter 10. Ion Exchange and Carbon Adsorption, 372

Introduction, 372

Theory and Practice of Ion Exchange, 374

Carbon Adsorption in Water Treatment, 404

Some Final Comments on Both Technologies, 432

Recommended Resources for the Reader, 440

Questions for Thinking and Discussing, 444

Chapter 11. Water Sterilization Technologies, 446

Introduction, 446

What Waterborne Diseases Are, 446

Treatment Options Available to Us, 450

Ozonation, 454

Ultraviolet Radiation, 455

V

Electron Beam, 455

Biology of Aquatic Systems, 456

Disinfection by Chlorination, 463

Disinfection with Interhalogens and Halogen Mixtures, 476

Sterilization Using Ozone, 482

Chapter 12. Treating the Sludge, 496

Introduction, 496

What Sludge Is, 497

What Stabilization and Conditioning Mean, 501

Sludge Dewatering Operations, 520

Volume Reduction, 550

What Finally Happens to Sludge after Volume Reduction, 565

Final Comments and Evaluating Economics, 582

Recommended Resources for the Reader, 592

Questions for Thinking and Discussing, 594

Glossary, 601

Index, 631

vi

Preface

This volume covers the technologies that are applied to the treatment and

purification of water. Those who are generally familiar with this field will

immediately embrace the subject as a treatise on solid-liquid separations. However,

the subject is much broader, in that the technologies discussed are not just restricted

to pollution control hardware that rely only upon physical methods of treating and

purifymg wastewaters. The book attempts to provide as wide a coverage as possible

those technologies applicable to both water (e.g., drinking water) and wastewater

(Le., industrial and municipal) sources. The methods and technologies discussed

are a combination of physical, chemical and thermal techniques.

There are twelve chapters. The first of these provides an orientation of terms and

concepts, along with reasons why water treatment practices are needed. This

chapter also sets the stage for the balance of the book by providing an

organizational structure to the subjects discussed. The second chapter covers the A￾B-Cs of filtration theory and practices, which is one of the fundamental unit

operations addressed in several chapters of the book. Chapter 3 begins to discuss

the chemistry of wastewater and focuses in on the use of chemical additives that

assist in physical separation processes for suspended solids. Chapters 4 through 7

cover technology-specific filtration practices. There is a wide range of hardware

options covered in these three chapters, with applications to both municipal and

industrial sides of the equation. Chapter 8 covers the subjects of sedimentation,

clarification flotation, and coalescence, and gets us back into some of the chemistry

issues that are important achieving high quality water. Chapter 9 covers membrane

separation technologies which are applied to the purification of drinking water.

Chapter 10 covers two very important water purification technologies that have

found applications not only in drinking water supply and beverage industry

applications, but in groundwater remediation applications. These technologies are

ion exchange and carbon adsorption. Chapter 11 covers chemical and non-chemical

water sterilization technologies, which are critical to providing high quality drinking

water. The last chapter focuses on the solid waste of wastewater treatment - sludge.

This chapter looks not only at physico-chemical and thermal methods of sludge

dewatering, but we explore what can be done with these wastes and their impact on

the overall costs that are associated with a water treatment plant operation. Sludge,

like water, can be conditioned and sterilized, thereby transforming it from a costly

waste, requiring disposal, to a useful byproduct that can enter into secondary

markets. Particular emphasis is given to pollution prevention technologies that are

not only more environmentally friendly than conventional waste disposal practices,

but more cost effective.

What I have attempted to bring to this volume is some of my own philosophy in

dealing with water treatment projects. As such, each chapter tries to embrace the

individual subject area from a first-principles standpoint, and then explore case-

specific approaches. Tackling problems in this field from a generalized approach

oftentimes enables us to borrow solutions and approaches to water treatment from

a larger arsenal of information. And a part of this arsenal is the worldwide Web.

This is not only a platform for advertising and selling equipment, but there is a

wealth of information available to help address various technical aspects of water

treatment. You will find key Web sites cited throughout the book, which are useful

to equipment selection and sizing, as well as for troubleshooting treatment plant

operational problems.

Most chapters include a section of recommended resources that I have relied upon

in my own consulting practice over the years, and believe you will also. In

addition, you will find a section titled Questions for Thinking and Discussing in

eleven of the twelve chapters. These chapter sections will get you thinking about

the individual subject areas discussed, and challenge you into applying some of the

calculation methods and methodologies reviewed. Although my intent was not to

create a college textbook, there is value in using this volume with engineering

students, either as a supplemental text or a primary text on water treatment

technologies. If used as such, instructors will need to gauge the level of

understanding of students before specifying the book for a course, as well as

integrate the sequence and degree of coverage provided in this volume, for

admittedly, for such a broad and complex subject, it is impossible to provide

uniform coverage of all areas in a single volume. My own experience in teaching

shows that the subject matter, at the level of presentation in this volume is best

suited to students with at least 3 years of engineering education under their belts.

Another feature that is incorporated into each chapter is the use of sidebar

discussions. These highlight boxes contain information and facts about each subject

area that help to emphasize important points to remember, plus can assist plant

managers in training technical staff, especially operators on the specific

technologies relied upon in their operations. Finally, there is a Glossary of several

hundred terms at the end of the book. This will prove useful to you not only when

reading through the chapters, but as a general resource reference.

In some cases equipment suppliers and tradenames are noted, however these

citations should not be considered an endorsement of products or services. They are

cited strictly for illustrative purposes. Also recognize, that neither I, nor the

publisher guarantee any designs emanating from the use of resources or discussions

presented herein. Final designs must be based upon strict adherence to local

engineering codes, and federal safety and environmental compliance standards.

A heartfelt thanks is extended to Butterworth-Heinemann Publishers for their fine

production of this volume, and in sharing my vision for this series, and to various

companies cited throughout the book that contributed materials and their time

Nicholas P. Cheremisinoff, Ph. D.

Washington, D. C.

viii

In Memory

This volume is dedicated to the memory of Paul Nicholas Cheremisinofl, P.E.,

who fathered a generation of pollution control and prevention specialists at New

Jersey Institute of Technology.

ix

About the Author

Nicholas P. Cheremisinoff is a private consultant to industry, lending institutions,

and donor agencies, specializing in pollution prevention and environmental

management. He has more than twenty years experience in applied research,

manufacturing and international business development, and has worked extensively

throughout Russia, Eastern Europe, Korea, Latin America, and the United States.

Dr. Cheremisinoff has contributed extensively to the industrial press, having

authored, co-authored or edited more than 100 technical reference books, and

several hundred articles, including Butterworth-Heinemann’s Green Profits: Tlte

Manager’s Handbook for IS0 14001 and Pollution Ppeventiors. He received his

B. S . , M. S . and Ph.D. degrees in chemical engineering from Clarkson College of

Technology. He can be reached by email at [email protected].

X

Foreword

This volume constitutes the beginning of what Butterworth-Heinemann Publishers

and I hope to provide to environmental and pollution control engineerdmanagers ,

namely an authoritative and extensive reference series covering control equipment

and technologies. As a chemical engineer and a consultant, I not only had the great

fortune of having a father, who was famous in the field of pollution control, but the

opportunity to work in consulting practice with him on a broad spectrum of

environmental problems within industry. We oftentimes talked and planned on

writing an authoritative volume on the hardware and technologies available to solve

pollution problems in the belief that, although there are many great works in the

technical literature, the levels of presentations of this important subject vary

dramatically and the information is fragmented. With my father’s untimely death

in 1994, and my commitment to a multi-year assignment, dealing with

environmental responsible care and the development of national environmental

policies in Ukraine and Russia, as part of contracts commitments to the U.S.

Agency for International Development and the European Union, the original

volume we intended was never written. Only now, having the opportunity to try and

bring this work forward, I recognize that no single volume can do adequate justice

to the subject area.

Also, there is the misconception among a younger generation of engineers that

pollution control can be displaced by pollution prevention practices, and hence

recent times have de-emphasized the need for engineering innovative pollution

controls. I am a strong proponent of pollution prevention, and indeed have

developed an international consulting practice around it. However, we should

recognize that oftentimes pollution prevention relies upon essentially the identical

technologies that are applied to so-called “end-of-pipe” treatment. It is the manner

in whch these technologies are applied, along with best management practices,

which enable pollution prevention to be practiced. As such, pollution prevention

does not replace the need for pollution controls, nor does it replace entire processes

aimed at cleaning or preventing pollutants from entering the environment. What it

does do is channel our efforts into applying traditional end-of-pipe treatment

technologies in such manners that costly practices for the disposal of pollutants are

avoided, and savings from energy efficiency and materials be achieved.

The volume represents the initial fulfillment of a series, and is aimed at assisting

process engineers, plant managers, environmental consultants, water treatment plant

operators, and students. Subsequent volumes are intended to cover air pollution

controls, and solid waste management and minimization.

This volume is a departure from the style of technical writing that I and many of

my colleagues have done in the past. What I have attempted is to discuss the

subject, rather than to try and teach or summarize the technologies, the hardware,

and selection criteria for different equipment. It’s a subject to discuss and explore,

rather than to present in a dry, strictly technical fashion. Water treatment is not

only a very important subject, but it is extremely interesting. Its importance is

simply one of environmental protection and public safety, because after all, water

is one of the basic natural elements we rely upon for survival. Even if we are

dealing with non-potable water supplies, the impact of poor quality water to process

operations can be devastating in terms of achieving acceptable process efficiencies

in heat exchange applications, in minimizing the maintenance requirements for heat

exchange and other equipment, in the quality of certain products that rely on water

as a part of their composition and processing, and ultimately upon the economics

of a process operation. It’s a fascinating subject, because the technology is both

rapidly changing, and cost-effective, energy-saving solutions to water treatment

require innovative solutions.

xii