Preface

The Safe Drinking Water Act Amendments of 1986 are the most sweeping legislative changes in the history of the public water supply field and will have more of an impact than the original act passed over two decades ago. These legislative changes reflect a perception by Congress that there is a great amount of public anxiety over the quality of our drinking water, as well as frustration with the manner in which the U.S. Environmental Protection Agency (USEPA) enforced the requirements of the original act. Practicing engineers and utility managers who are involved with the planning, design, and operation of water treatment plants must begin to evaluate current options and anticipate what lies ahead. At the present time, many programs in civil and environmental engineering at numerous universities are offering courses in the area of water treatment plant design.

Several excellent books have been written in recent years that present theory and principles of water treatment processes. The authors have observed during their years of experience in the water treatment field that no publication has been devoted entirely to water works engineering planning, design, and operation. The intent of the authors in developing this book is twofold: first, to consolidate the developments in design of water works engineering that have evolved as a result of technological advancement in the field and of the concepts and policies promulgated by the environmental laws and the subsequent guidelines; second, to develop step-by-step procedures for planning, design, and operation of a medium-size conventional water treatment plant.

This book has a total of nineteen chapters and four appendices. Chapters 1 through 4 are devoted to the basic facts of water engineering. Current and future trends in water treatment technology, water quality constituents, design factors, drinking water regulations, unit operations and processes, process combinations, and process trains are discussed in detail.

Chapter 5 is devoted to preparation of a predesign report. The general purpose of a predesign engineering report and an example of a model predesign report for a medium-size water supply project are presented. In this predesign report, procedures are presented for (1) estimation of population, water demand, plant capacity, and raw water quality; (2) evaluation and selection of a treatment process train; (3) coordination with distribution system; and (4) estimation of costs for proposed capital improvement project.

The remainder of the book is devoted to the design of the medium-size water treatment facility for which the predesign report is developed in Chapter 5. Step-by-step design calculations; equipment details; engineering drawings, plans, and specifications; and operation and maintenance of head works, raw water transport, treatment, and distribution systems: all are presented. These systems include raw water intake, screening, pump station, transport pipeline, flow measurement, rapid mix, flocculation, clarification, filtration, color, taste and odor control, disinfection, distribution, and residuals handling and disposal. Also, separate chapters have been devoted to plant layout, yard piping and hydraulics, instrumentation and automatic controls, design summary, and the avoidance of design errors. A separate chapter (Chapter 18) is provided to cover nonconventional treatment processes. In this chapter, the treatment processes for nitrate and fluoride removal, ion exchange, reverse osmosis, and heavy metals and organics removal are briefly presented.

The design procedures given in this book are for illustration and general information only and are not intended to be used as standard for water treatment plant designs. References made in this publication to specific methods, processes, and equipment do not constitute or imply an endorsement or recommendation. Equivalent or improved equipment may be obtained from many other manufacturers not mentioned in this publication.

This book will serve the needs of students, teachers, consulting engineers, equipment manufacturers, and technical personnel in city, state, and federal organizations who must review designs and specifications. In order to maximize the usefulness of this book, the material has been presented in a simplified and concise format. Many tables have been developed using a variety of sources. Those tables provide information used extensively in water treatment plant design. Basic properties of water, hydraulic design information, chemical properties and equipment selection, equipment manufacturers, cost equations, and unit conversions are arranged in four appendices.

It should be mentioned that a great deal of emphasis has been given to the predesign report and the design of conventional water treatment units. The authors are well aware of the fact that equal emphasis or in-depth design procedures for many other nonconventional water treatment processes such as denitrification, defluoridation, demineralization, and other specialized processes (briefly presented in Chapters 3 and 18) are not given elsewhere in this book. The reason is very simple. Covering design procedures for these processes would take another book of equal size. The authors strongly believe that the planning and design principles developed in this book can easily be extended to the design of many other treatment processes for a new plant or the upgrading of an existing facility. Therefore, the in-depth coverage and step-by-step design procedure for an entire conventional water treatment plant is the strongest feature of this publication.

This book is intended for a design course in water works engineering. Most of the programs in civil and environmental engineering are offering such courses at graduate and undergraduate levels. The material is developed in such a way that the normal prerequisites (fluid mechanics and an introductory course in water supply and wastewater treatment) would be sufficient. Furthermore, the basic material contained in this book can be covered in a three-semester credit course.

In this country, because the old plants will be upgraded in the future, the U.S. customary units will continue to be in use for some time to come. Therefore, where possible, both systems of units are used side-by-side, and proper conversion factors are provided. Complete conversion tables are given separately in an appendix.