Water Wastewater Treatment Plant Operations

In Handbook of Water and Wastewater Treatment Plant Operations, the intent of the author is twofold. The first intent is to consolidate the information and experience in waterworks and wastewater treatment plant operations that have evolved as a result of technological advances in the field, and as a result of the concepts and policies promulgated by the environmental laws and the subse-quent guidelines. The second intent is to discuss step-by-step procedures for the correct and efficient operation of water and wastewater treatment systems. Tertiary to this twofold intent is the proper preparation of operators to qualify for state licensure and certification examinations. With the impetus given to water quality improvement through the Municipal Construction Grants Program, the United States has undertaken an unprecedented building program for new and improved water and wastewater treat-ment systems. To date, much emphasis has been placed on training engineers to plan, design, and construct treatment facilities. At present, many programs in various engineer-ing disciplines at many universities offer courses in water and wastewater treatment plant design and operation. This text is not about the planning, designing, or con-struction of water and wastewater treatment facilities. While these tasks are paramount to conception and con-struction of needed facilities and needed infrastructure, many excellent texts are available that cover these impor-tant areas. This text is not about engineering at all. Instead, it is about operations and is designed for the operator. We often forget the old axiom: someone must build it, but once built, someone must operate it. It is the operation of ìitî that concerns us here

pdf669 trang | Chia sẻ: lvcdongnoi | Ngày: 12/01/2013 | Lượt xem: 1970 | Lượt tải: 0download
Bạn đang xem nội dung tài liệu Water Wastewater Treatment Plant Operations, để tải tài liệu về máy bạn click vào nút DOWNLOAD ở trên
LEWIS PUBLISHERS A CRC Press Company Boca Raton London New York Washington, D.C. Water and Wastewater Treatment Plant Operations Handbook of Frank R. Spellman© 2003 by CRC Press LLC This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microÞlming, and recording, or by any information storage or retrieval system, without prior permission in writing from the publisher. The consent of CRC Press LLC does not extend to copying for general distribution, for promotion, for creating new works, or for resale. SpeciÞc permission must be obtained in writing from CRC Press LLC for such copying. Direct all inquiries to CRC Press LLC, 2000 N.W. Corporate Blvd., Boca Raton, Florida 33431. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identiÞcation and explanation, without intent to infringe. Visit the CRC Press Web site at www.crcpress.com © 2003 by CRC Press LLC Lewis Publishers is an imprint of CRC Press LLC No claim to original U.S. Government works International Standard Book Number 1-56670-627-0 Library of Congress Card Number 2003040119 Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 Printed on acid-free paper Library of Congress Cataloging-in-Publication Data Spellman, Frank R. Handbook of water & wastewater treatment plant operations / by Frank R. Spellman. p. cm. Includes bibliographical references and index. ISBN 1-56670-627-0 (alk. paper) 1. Water—treatment plants—Handbooks, manuals, etc. 2. Sewage disposal plants—Handbooks, manuals, etc. 3. Water—PuriÞcation—Handbooks, manuals, etc. 4. Sewage—PuriÞcation—Handbooks, manuals, etc. I. Title: Handbook of water and wastewater treatment plant operations. II. Title. TD434.S64 2003 628.1¢62—dc21 2003040119© 2003 by CRC Press LLC Preface Water does not divide; it connects. With simplicity it links all aspects of our existence. David Rothenberg and Marta Ulvaenus In Handbook of Water and Wastewater Treatment Plant Operations, the intent of the author is twofold. The Þrst intent is to consolidate the information and experience in waterworks and wastewater treatment plant operations that have evolved as a result of technological advances in the Þeld, and as a result of the concepts and policies promulgated by the environmental laws and the subse- quent guidelines. The second intent is to discuss step-by- step procedures for the correct and efÞcient operation of water and wastewater treatment systems. Tertiary to this twofold intent is the proper preparation of operators to qualify for state licensure and certiÞcation examinations. With the impetus given to water quality improvement through the Municipal Construction Grants Program, the United States has undertaken an unprecedented building program for new and improved water and wastewater treat- ment systems. To date, much emphasis has been placed on training engineers to plan, design, and construct treatment facilities. At present, many programs in various engineer- ing disciplines at many universities offer courses in water and wastewater treatment plant design and operation. This text is not about the planning, designing, or con- struction of water and wastewater treatment facilities. While these tasks are paramount to conception and con- struction of needed facilities and needed infrastructure, many excellent texts are available that cover these impor- tant areas. This text is not about engineering at all. Instead, it is about operations and is designed for the operator. We often forget the old axiom: someone must build it, but once built, someone must operate it. It is the operation of “it” that concerns us here. Several excellent texts have been written on water and wastewater treatment plant operations. Thus, the logical question is, why a new text covering a well-trodden road? The compound answer is a text that is comprehensive in scope, current, and deals with real world problems involved with plant operations is needed. The simple answer is that after September 11, things have changed. Many of these changes were apparent before Septem- ber 11; at the same time, many of our present needs were not so apparent. Consider, for example, the need for plants to become more efÞcient in operation and more economical in practice. This is not new, but it now takes on added importance because of the threat of privatization. We cover privatization and the benchmarking process in this text. On the other hand, how many of us thought security was a big deal prior to September 11? Some of us did, while some of us did not give it any thought at all. Today, things are different; we must adjust or fall behind. In the present climate, falling behind on the security of our potable water supplies is not an option. We must aggressively protect our precious water sources and those ancillaries that are critical to maintaining and protecting water quality. We cover plant security concerns in this text. There are other current issues. For example, arsenic in drinking water received a lot of coverage in the press recently. We all know that arsenic is a deadly poison, depending on dose, of course. Headlines stating that arsenic has been found in certain municipal drinking water supplies are a red ßag issue to many people. But is it really an issue? We cover arsenic in drinking water in this text. Another red ßag issue that has received some press and the attention of regulators is the presence of patho- genic protozoans, such as Giardia and Cryptosporidium, in drinking water supplies. We cover both of these proto- zoans in this text. In wastewater treatment (as well as water treatment), a lot of attention has been focused on disinfection by- products in water efßuents outfalled into receiving water bodies. We cover disinfection by-products in this text. Water and wastewater treatment is about mitigating the problems mentioned above. However, treatment oper- ations are about much more. To handle today’s problems, water and wastewater treatment system operators must be generalists. Herein lies the problem. Many of the texts presently available for water and wastewater operator use are limited in scope and narrowly focused in content. Most of these texts take a bare bones approach to presentation. That is, the basics of each unit process are usually ade- quately covered, but this is the extent of the coverage. At present, available texts either ignore, avoid, or pay cursory attention to such important areas as the multiple- barrier concept, maintaining infrastructure, benchmarking, plant security, operator roles, water hydraulics, microbi- ology, water ecology, basic electrical principles, pumping, conveyance, ßow measurement, basic water chemistry, water quality issues, biomonitoring, sampling and testing, water sources, and watershed protection. All of these important topics are thoroughly discussed in Handbook of Water and Wastewater Treatment Plant Operations. Though directed at water and wastewater operators, this book will serve the needs of students; teachers; con-© 2003 by CRC Press LLC sulting engineers; and technical personnel in city, state, and federal organizations who must review operations and operating procedures. In order to maximize the usefulness of the material contained in the test, it has been presented in plain English in a simpliÞed and concise format. Many tables have been developed, using a variety of sources. To assure correlation to modern practice and design, illustrative problems are presented in terms of commonly used operational parameters. Each chapter ends with a chapter review test to help evaluate mastery of the concepts presented. Before going on to the next chapter, take the review test, compare your answers to the key provided in Appendix A, and review the pertinent information for any problems you missed. If you miss many items, review the whole chapter. The indented notes displayed in various locations throughout this text indicate or emphasize important points to study carefully. This text is accessible to those who have no experience with water and wastewater operations. If you work through the text systematically, you can acquire an under- standing of and skill in water and wastewater operations. This will add a critical component to your professional knowledge. Frank R. Spellman Norfolk, VA© 2003 by CRC Press LLC Contents PART I Water and Wastewater Operations: An Overview Chapter 1 Problems Facing Water and Wastewater Treatment Operations 1.1 Introduction 1.2 The Paradigm Shift 1.2.1 A Change in the Way Things are Understood and Done 1.3 Multiple-Barrier Concept 1.3.1 Multiple-Barrier Approach: Wastewater Operations 1.4 Management Problems Facing Water and Wastewater Operations 1.4.1 Compliance with New, Changing, and Existing Regulations 1.4.2 Maintaining Infrastructure 1.4.3 Privatizing and/or Reengineering 1.4.4 Benchmarking Benchmarking: The Process 1.4.5 The Bottom Line on Privatization 1.5 Upgrading Security 1.5.1 The Bottom Line on Security 1.6 Technical Management vs. Professional Management 1.7 Chapter Review Questions and Problems References Chapter 2 Water and Wastewater Operators and Their Roles 2.1 Water and Wastewater Operators 2.2 Setting the Record Straight 2.2.1 The Computer-Literate Jack 2.2.2 Plant Operators as Emergency Responders 2.2.3 Operator Duties, Numbers, and Working Conditions 2.3 Operator CertiÞcation/Licensure 2.4 Chapter Review Questions and Problems References Chapter 3 Water and Wastewater References, Models, and Terminology 3.1 Setting the Stage 3.2 Treatment Process Models 3.3 Key Terms Used in Waterworks and Wastewater Operations 3.3.1 Terminology and DeÞnitions 3.4 Chapter Review Question and Problems References© 2003 by CRC Press LLC PART II Water/Wastewater Operations: Math and Technical Aspects Chapter 4 Water and Wastewater Math Operations 4.1 Introduction 4.2 Calculation Steps 4.3 Table of Equivalents, Formulae, and Symbols 4.4 Typical Water and Wastewater Math Operations 4.4.1 Arithmetic Average (or Arithmetic Mean) and Median 4.4.2 Ratio 4.4.3 Percent Practical Percentage Calculations 4.4.4 Units and Conversions Temperature Conversions Milligrams per Liter (Parts per Million) 4.5 Measurements: Areas and Volumes 4.5.1 Area of a Rectangle 4.5.2 Area of a Circle 4.5.3 Area of a Circular or Cylindrical Tank 4.5.4 Volume Calculations Volume of Rectangular Tank Volume of a Circular or Cylindrical Tank Example Volume Problems 4.6 Force, Pressure, and Head 4.7 Flow 4.7.1 Flow Calculations Instantaneous Flow Rates Flow through a Full Pipeline 4.7.2 Velocity Calculations 4.7.3 Average Flow Rate Calculations 4.7.4 Flow Conversion Calculations 4.8 Detention Time 4.8.1 Hydraulic Detention Time Detention Time in Days Detention Time in Hours Detention Time in Minutes 4.9 Chemical Dosage Calculations 4.9.1 Chlorine Dosage 4.9.2 Hypochlorite Dosage 4.10 Percent Removal 4.11 Population Equivalent or Unit Loading Factor 4.12 SpeciÞc Gravity 4.13 Percent Volatile Matter Reduction in Sludge 4.14 Horsepower 4.14.1 Water Horsepower 4.14.2 Brake Horsepower 4.14.3 Motor Horsepower 4.15 Electrical Power 4.16 Chemical Coagulation and Sedimentation 4.16.1 Calculating Feed Rate 4.16.2 Calculating Solution Strength 4.17 Filtration 4.17.1 Calculating the Rate of Filtration 4.17.2 Filter Backwash© 2003 by CRC Press LLC 4.18 Practical Water Distribution System Calculations 4.18.1 Water Flow Velocity 4.18.2 Storage Tank Calculations 4.18.3 Distribution System Disinfection Calculations 4.19 Complex Conversions 4.19.1 Concentration to Quantity Concentration (Milligrams per Liter) to Pounds Concentration (Milligrams per Liter) to Pounds/Day Concentration (Milligrams per Liter) to Kilograms per Day Concentration (milligrams/kilogram) to pounds/ton 4.19.2 Quantity to Concentration Pounds to Concentration (Milligrams per Liter) Pounds per Day to Concentration (Milligrams per Liter) Kilograms per Day to Concentration (Milligrams per Liter) 4.19.3 Quantity to Volume or Flow Rate Pounds to Tank Volume (Million Gallons) Pounds per Day to Flow (Million Gallons per Day) Kilograms per Day to Flow (Million Gallons per Day) 4.20 Chapter Review Questions and Problems Reference Chapter 5 Water Hydraulics 5.1 What is Water Hydraulics? 5.2 Basic Concepts 5.2.1 Stevin’s Law 5.3 Properties of Water 5.3.1 Density and SpeciÞc Gravity 5.4 Force and Pressure 5.4.1 Hydrostatic Pressure 5.4.2 Effects of Water under Pressure 5.5 Head 5.5.1 Static Head 5.5.2 Friction Head 5.5.3 Velocity Head 5.5.4 Total Dynamic Head (Total System Head) 5.5.5 Pressure/Head 5.5.6 Head/Pressure 5.6 Flow/Discharge Rate: Water in Motion 5.6.1 Area/Velocity 5.6.2 Pressure/Velocity 5.7 Piezometric Surface and Bernoulli’s Theorem 5.7.1 Law of Conservation of Energy 5.7.2 Energy Head 5.7.3 Piezometric Surface Head Loss Hydraulic Grade Line 5.7.4 Bernoulli’s Theorem Bernoulli’s Equation 5.8 Hydraulic Machines (Pumps) 5.8.1 Pumping Hydraulics 5.9 Well and Wet Well Hydraulics 5.9.1 Well Hydraulics 5.9.2 Wet Well Hydraulics© 2003 by CRC Press LLC 5.10 Friction Head Loss 5.10.1 Flow in Pipelines 5.10.2 Pipe and Open Flow Basics 5.10.3 Major Head Loss Components of Major Head Loss Calculating Major Head Loss 5.10.4 Minor Head Loss 5.11 Basic Piping Hydraulics 5.11.1 Piping Networks Energy Losses in Pipe Networks Pipes in Series Pipes in Parallel 5.12 Open-Channel Flow 5.12.1 Characteristics of Open-Channel Flow Laminar and Turbulent Flow Uniform and Varied Flow Critical Flow Parameters Used in Open-Channel Flow 5.12.2 Open-Channel Flow Calculations 5.12.3 Open-Channel Flow: The Bottom Line 5.13 Flow Measurement 5.13.1 Flow Measurement: The Old-Fashioned Way 5.13.2 Basis of Traditional Flow Measurement 5.13.3 Flow Measuring Devices Differential Pressure Flowmeters Magnetic Flowmeters Ultrasonic Flowmeters Velocity Flowmeters Positive-Displacement Flowmeters 5.13.4 Open-Channel Flow Measurement Weirs Flumes 5.14 Chapter Review Questions and Problems References Chapter 6 Fundamentals of Electricity 6.1 Electricity: What Is It? 6.2 Nature of Electricity 6.3 The Structure of Matter 6.4 Conductors, Semiconductors, and Insulators 6.5 Static Electricity 6.5.1 Charged Bodies 6.5.2 Coulomb’s Law 6.5.3 Electrostatic Fields 6.6 Magnetism 6.6.1 Magnetic Materials 6.6.2 Magnetic Earth 6.7 Difference in Potential 6.7.1 The Water Analogy 6.7.2 Principal Methods of Producing Voltage 6.8 Current 6.9 Resistance 6.10 Battery-Supplied Electricity© 2003 by CRC Press LLC 6.10.1 The Voltaic Cell 6.10.2 Primary and Secondary Cells 6.10.3 Battery Battery Operation Combining Cells 6.10.4 Types of Batteries Dry Cell Lead-Acid Battery Alkaline Cell Nickel-Cadmium Cell Mercury Cell Battery Characteristics 6.11 The Simple Electrical Circuit 6.11.1 Schematic Representation 6.12 Ohm’s law 6.13 Electrical Power 6.13.1 Electrical Power Calculations 6.14 Electrical Energy 6.15 Series DC Circuit Characteristics 6.15.1 Series Circuit Resistance 6.15.2 Series Circuit Current 6.15.3 Series Circuit Voltage 6.15.4 Series Circuit Power 6.15.5 Summary of the Rules for Series DC Circuits 6.15.6 General Series Circuit Analysis Kirchhoff’s Voltage Law 6.16 Ground 6.17 Open and Short Circuits 6.18 Parallel DC Circuits 6.18.1 Parallel Circuit Characteristics 6.18.2 Voltage in Parallel Circuits 6.18.3 Current in Parallel Circuits 6.18.4 Parallel Circuits and Kirchhoff’s Current Law 6.18.5 Parallel Circuit Resistance Reciprocal Method Product over the Sum Method Reduction to an Equivalent Circuit 6.18.6 Power in Parallel Circuits 6.18.7 Rules for Solving Parallel DC Circuits 6.19 Series-Parallel Circuits 6.19.1 Solving a Series-Parallel Circuit 6.20 Conductors 6.20.1 Unit Size of Conductors Square Mil Circular Mil Circular-Mil-Foot Resistivity Wire Measurement 6.20.2 Factors Governing the Selection of Wire Size Copper vs. Other Metal Conductors Temperature CoefÞcient 6.20.3 Conductor Insulation 6.20.4 Conductor Splices and Terminal Connections 6.20.5 Soldering Operations© 2003 by CRC Press LLC 6.20.6 Solderless Connections 6.20.7 Insulation Tape 6.21 Electromagnetism 6.21.1 Magnetic Field around a Single Conductor 6.21.2 Polarity of a Single Conductor 6.21.3 Field around Two Parallel Conductors 6.21.4 Magnetic Field of a Coil Polarity of an Electromagnetic Coil Strength of an Electromagnetic Field 6.21.5 Magnetic Units 6.21.6 Properties of Magnetic Materials Permeability Hysteresis 6.21.7 Electromagnets 6.22 AC Theory 6.22.1 Basic AC Generator Cycle Frequency, Period, and Wavelength 6.22.2 Characteristic Values of AC Voltage and Current Peak Amplitude Peak-to-Peak Amplitude Instantaneous Amplitude Effective or Root-Mean-Square Value Average Value 6.22.3 Resistance in AC Circuits 6.22.4 Phase Relationships 6.23 Inductance 6.23.1 Self-Inductance 6.23.2 Mutual Inductance 6.23.3 Calculation of Total Inductance 6.24 Practical Electrical Applications 6.24.1 Electrical Power Generation 6.24.2 DC Generators 6.24.3 AC Generators 6.24.4 Motors DC Motors AC Motors 6.24.5 Transformers 6.24.6 Power Distribution System Protection Fuses Circuit Breakers Control Devices 6.25 Chapter Review Questions and Problems Chapter 7 Hydraulic Machines: Pumps 7.1 Introduction 7.2 Archimedes’ Screw 7.3 Pumping Hydraulics 7.3.1 DeÞnitions 7.4 Basic Principles of Water Hydraulics 7.4.1 Weight of Air 7.4.2 Weight of Water 7.4.3 Weight of Water Related to the Weight of Air 7.4.4 Water at Rest© 2003 by CRC Press LLC 7.4.5 Gauge Pressure 7.4.6 Water in Motion Discharge The Law of Continuity 7.4.7 Pipe Friction 7.5 Basic Pumping Calculations 7.5.1 Pumping Rates 7.5.2 Calculating Head Loss 7.5.3 Calculating Head 7.5.4 Calculating Horsepower and EfÞciency Hydraulic Horsepower Pump EfÞciency and Brake Horsepower 7.5.5 SpeciÞc Speed 7.6 Pump Characteristic Curves 7.6.1 Head-Capacity Curve 7.6.2 The Power-Capacity Curve 7.6.3 The EfÞciency-Capacity (E-Q) Curve 7.7 Pumps in Series and Parallel 7.8 Considerations for Pumping Wastewater 7.9 Types of Pumps Used in Water and Wastewater Treatment 7.10 Introduction to Centrifugal Pumps 7.10.1 Description 7.10.2 Theory 7.10.3 Types of Centrifugal Pumps Radial Flow Impeller Pumps Mixed Flow Impeller Pumps Axial Flow Impeller Pumps (Propeller Pump) 7.10.4 Characteristics and Performance Curves Head-Capacity Curve EfÞciency Curve Brake Horsepower Curves 7.10.5 Advantages and Disadvantages of a Centrifugal Pump Advantages Disadvantages 7.10.6 Water and Wastewater Applications 7.11 Centrifugal Pump Components 7.11.1 Casing Solid Casing Split Casings 7.11.2 Impeller Semiopen Impeller Open Impeller Closed Impeller 7.11.3 Wear Rings 7.11.4 Shafts, Sleeves, and Couplings Shafting Sleeves Couplings 7.11.5 StufÞng Box and Seals StufÞng Box or Packing Assembly Mechanical Seals 7.11.6 Bearings Self-Aligning Double-Row Ball Bearing Single- or Double-Row Antifriction Ball Bearing Angular Contact Bearings© 2003 by CRC Press LLC Self-Aligning Spherical Roller Bearings Single-Row Tapered Roller Bearings Bearing Installation, Maintenance and Lubrication 7.12 Centrifugal Pump: Operational Procedures 7.12.1 Installation 7.12.2 Start-Up Start-Up Procedure 7.12.3 Normal Operation 7.12.4 Shutdown 7.12.5 Priming Priming Procedure 7.12.6 Backßushing Backßush Procedure 7.12.7 Manual Removal Procedure 7.13 Centrifugal Pump: Maintenance Procedures 7.13.1 Pump and Motor Lubrication 7.13.2 Packing and Seal Replacement Packing Procedure Mechanical Seal Installation Procedure 7.13.3 Pump and Motor Bearing Inspection 7.13.4 Shaft and Coupling Alignment Alignment Procedure Removal of Obstructions 7.14 Centrifugal Pumps Preventive Maintenance 7.14.1 Daily Maintenance 7.14.2 Weekly Maintenance 7.14.3 Monthly Maintenance 7.14.4 Quarterly Maintenance 7.14.5 Semiannual Maintenance 7.15 Centrifugal Pump Lubrication 7.15.1 Purpose of Lubrication Separates Surfaces Prevents Wear Cushions Shock Transfers Heat Corrosion Protection Protective Seal 7.15.2 Lubrication Requirements 7.15.3 Lubrication Procedures Motor Bearing Lubrication Pump Bearing Lubrication 7.16 Centrifugal Pump: Troubleshooting 7.16.1 The Troubleshooter 7.16.2 Troubleshooting: What Is It? 7.16.3 Goals of Troubleshooting 7.16.4 The Troubleshooting Process 7.16.5 Troubleshooting the Centrifugal Pump Pump Fails to Prime or Loses its Prime Pump Does Not Discharge Pump Does Not Deliver Rated Capacity Pump Does Not Deliver SufÞcient Pressure Pump Starts and Stops Pumping Pump Overloads Driver or Consumes Excessive Power Pump Is Noisy or Has Extensive Vibration Packing Has a Short Life© 2003 by CRC Press LLC Mechanical Seal Has a Short Life Mechanical Seal Leaks Excessively Bearings Have a Short Life Pump Overheats or Seizes 7.17 Centrifugal Pump ModiÞcations 7.17.1 Submersible Pumps Applications Advantages Disadvantages 7.17.2 Recessed Impeller or Vortex Pumps Applications Advantages Disadvantages 7.17.3 Turbine Pumps Application Advantages Disadvantages 7.18 Positive-Displacement Pumps 7.18.1 Reciprocating Pumps Diaphragm Pumps Metering Pumps Rotary Pumps Progressive-Cavity Pump Special Purpose Pumps 7.19 Chapter Review Questions and Problems References Chapter 8 Water and Wastewater Conveyance 8.1 Delivering the Lifeblood of Civilization 8.2 Conveyance Systems 8.2.1 DeÞnitions 8.2.2 Fluids vs. Liquids 8.2.3 Maintaining Fluid Flow in Piping Systems Scaling 8.2.4 Piping System Maintenance 8.2.5 Valves 8.2.6 Piping System Accessories 8.2.7 Piping Systems: Temperature Effects 8.2.8 Piping Systems: Insulation 8.3 Metallic Piping 8.3.1 Piping Materials 8.3.2 Piping: The Basics Pipe Sizes Pipe Wall Thickness Piping ClassiÞcation 8.3.3 Types of Piping Systems Code for IdentiÞcation of Pipelines 8.3.4 Metallic Piping Materials Characteristics of Metallic Materials 8.3.5 Maintenance Characteristics of Metallic Piping Expansion and Flexibility Pipe Support Systems Valve Selection Isolation© 2003 by CRC Press LLC Preventing Backßow Water Hammer Air Binding Corrosion Effects 8.3.6 Joining Metallic Pipe Bell-and-Spigot Joints Screwed or Threaded Joints Flanged Joints Welded Joints Soldered and Brazed Joints 8.4 Nonmetallic Piping 8.4.1 Nonmetallic Piping Materials Clay Pipe Concrete Pipe Plastic Pipe 8.5 Tubing 8.5.1 Tubing vs. Piping: The Difference Tubing 8.5.2 Advantages of Tubing Tubing: Mechanical Advantages Chemical Advantages 8.5.3 Connecting Tubing Cutting Tubing Soldering Tubing Connecting Flared/Nonßared Joints 8.5.4 Bending Tubing 8.5.5 Types of Tubing Typical Tubing Applications 8.6 Industrial Hoses 8.6.1 Hose Nomenclature 8.6.2 Factors Governing Hose Selection 8.6.3 Standards, Codes, and Sizes Hose Size 8.6.4 Hose ClassiÞcations Nonmetallic Hoses Metallic Hoses 8.6.5 Hose Couplings 8.6.6 Hose Maintenance 8.7 Pipe and Tube Fittings 8.7.1 Fittings 8.7.2 Functions of Fittings Changing the Direction of Flow Providing Branch Connections Changing the Sizes of Lines Sealing Lines Connecting Lines 8.7.3 Types of Connections Screwed Fittings Flanged Connections Connections 8.7.4 Tubing Fittings and Connections 8.8 Valves 8.8.1 Valve Construction 8.8.2 Types of Valves© 2003 by CRC Press LLC Ball Valves Gate Valves Globe Valves Needle Valves Butterßy Valves Plug Valves Check Valves Quick-Opening Valves Diaphragm Valves Regulating Valves Relief Valves Reducing Valves 8.8.3 Valve Operators Pneumatic and Hydraulic Valve Operators Magnetic Valve Operators 8.8.4 Valve Maintenance 8.9 Piping System: Protective Devices 8.9.1 Applications 8.9.2 Strainers 8.9.3 Filters 8.9.4 Traps Trap Maintenance and Testing 8.10 Piping Ancillaries 8.10.1 Gauges Pressure Gauges 8.10.2 Vacuum Breakers 8.10.3 Accumulators 8.10.4 Air Receivers 8.10.5 Heat Exchangers 8.11 Chapter Review Questions and Problems References Chapter 9 Flow Measurement 9.1 Introduction 9.2 Methods of Measuring Flow 9.2.1 Weirs 9.2.2 The Oscillating Disk Water Meter 9.2.3 Flumes 9.2.4 Venturi Meter 9.2.5 Magnetic Flowmeter 9.3 Flow Measurement Calculations 9.3.1 Calculation Method Used for Fill and Draw Technique 9.3.2 Calculation Method Used for Velocity/Area Technique 9.3.3 Calculation Method Used for V-Notch Weirs 9.3.4 Weir Overßow (Weir Loading Rate) 9.3.5 Calculation Method for Parshall Flume 9.3.6 Typical Flow Measurement Practice Calculations 9.4 Flow Measurement Operational Problems 9.5 Chapter Review Questions and Problems References© 2003 by CRC Press LLC Part III Characteristics of Water Chapter 10 Basic Water Chemistry 10.1 Introduction 10.2 Chemistry Concepts and DeÞnitions 10.2.1 Concepts 10.2.2 DeÞnitions 10.3 Water Chemistry Fundamentals 10.3.1 Matter The Content of Matter: The Elements 10.3.2 Compound Substances 10.4 The Water Molecule 10.5 Water Solutions 10.6 Water Constituents 10.6.1 Solids 10.6.2 Turbidity 10.6.3 Color 10.6.4 Dissolved Oxygen 10.6.5 Metals 10.6.6 Organic Matter 10.6.7 Inorganic Matter Acids Bases Salts 10.7 pH 10.8 Alkalinity 10.9 Hardness 10.10 Water and Wastewater Chemicals and Chemical Processes 10.10.1 Odor Control (Wastewater Treatment) 10.10.2 Disinfection 10.10.3 Chemical Precipitation 10.10.4 Adsorption 10.10.5 Coagulation 10.10.6 Taste and Odor Removal 10.10.7 Water Softening 10.10.8 Recarbonation 10.10.9 Ion Exchange Softening 10.10.10 Scaling and Corrosion Control 10.11 Chapter Review Questions and Problems References Chapter 11 Water Microbiology 11.1 Introduction 11.2 Microbiology: What Is It? 11.3 Water and Wastewater Microorganisms 11.3.1 Key Terms 11.3.2 Microorganisms (in General) 11.3.3 ClassiÞcation 11.3.4 Differentiation 11.3.5 The Cell Structure of the Bacterial Cell© 2003 by CRC Press LLC 11.4 Bacteria 11.4.1 Bacterial Growth Factors 11.4.2 Destruction of Bacteria 11.4.3 Waterborne Bacteria 11.5 Protozoa 11.6 Microscopic Crustaceans 11.7 Viruses 11.8 Algae 11.9 Fungi 11.10 Nematodes and Flatworms (Worms) 11.11 Pathogenic Protozoa and Helminths (Water) 11.11.1 Pathogenic Protozoa Giardia Cryptosporidium Cyclospora 11.11.2 Helminths 11.12 Biological Aspects and Processes (Wastewater) 11.12.1 Aerobic Process 11.12.2 Anaerobic Process 11.12.3 Anoxic Process 11.12.4 Photosynthesis 11.12.5 Growth Cycles 11.12.6 Biogeochemical Cycles Carbon Cycle Nitrogen Cycle Sulfur Cycle Phosphorus Cycle 11.13 Chapter Review Questions and Problems References Chapter 12 Water Ecology 12.1 Introduction 12.2 Setting the Stage 12.3 Ecology Terms 12.3.1 DeÞnition of Terms 12.4 Levels of Organization 12.5 Ecosystem 12.6 Energy Flow in the Ecosystem 12.7 Food Chain EfÞciency 12.8 Ecological Pyramids 12.9 Productivity 12.10 Population Ecology 12.11 Stream Genesis and Structure 12.11.1 Water Flow in a Stream 12.11.2 Stream Water Discharge 12.11.3 Transport of Material 12.11.4 Characteristics of Stream Channels 12.11.5 Stream ProÞles 12.11.6 Sinuosity 12.11.7 Bars, Rifßes, and Pools 12.11.8 The Floodplain 12.11.9 Adaptations to Stream Current© 2003 by CRC Press LLC 12.11.10 Types of Adaptive Changes 12.11.11 SpeciÞc Adaptations 12.12 Benthic Life: An Overview 12.12.1 Benthic Plants and Animals 12.13 Benthic Macroinvertebrates 12.13.1 IdentiÞcation of Benthic Macroinvertebrates 12.13.2 Macroinvertebrates and the Food Web 12.13.3 Units of Organization 12.13.4 Typical Running Water Benthic Macroinvertebrates 12.14 Insect Macroinvertebrates 12.14.1 Mayßies (Order: Ephemeroptera) 12.14.2 Stoneßies (Order: Plecoptera) 12.14.3 Caddisßies (Order: Trichoptera) 12.14.4 True Flies (Order: Diptera) 12.14.5 Beetles (Order: Coleoptera) 12.14.6 Water Strider (Jesus bugs; Order: Hemiptera) 12.14.7 Alderßies and Dobsonßies (Order: Megaloptera) 12.14.8 Dragonßies and Damselßies (Order: Odonata) 12.15 Noninsect Macroinvertebrates 12.15.1 Oligochaeta (Family: TuiÞcidae; Genus: Tubifex) 12.15.2 Hirudinea (Leeches) 12.14.3 Gastropoda (Lung-Breathing Snail) 12.16 Chapter Review Questions and Problems References Chapter 13 Water Quality 13.1 Introduction 13.2 The Water Cycle 13.3 Water Quality Standards 13.3.1 Clean Water Act (1972) 13.3.2 Safe Drinking Water Act (1974) 13.4 Water Quality Characteristics of Water and Wastewater 13.4.1 Physical Characteristics of Water and Wastewater Solids Turbidity Color Taste and Odor Temperature 13.4.2 Chemical Characteristics of Water Total Dissolved Solids (TDS) Alkalinity Hardness Fluoride Metals Organics Nutrients 13.4.3 Chemical Characteristics of Wastewater Organic Substances Inorganic Substances 13.4.4 Biological Characteristics of Water and Wastewater Bacteria Viruses Protozoa Worms (Helminths)© 2003 by CRC Press LLC 13.5 Chapter Review Questions and Problems References Chapter 14 Biomonitoring, Monitoring, Sampling, and Testing 14.1 What Is Biomonitoring? 14.1.1 Biotic Indices (Streams) Benthic Macroinvertebrate Biotic Index 14.2 Biological Sampling (Streams) 14.2.1 Biological Sampling: Planning 14.2.2 Sampling Stations 14.2.3 Sample Collection Macroinvertebrate Sampling Equipment Macroinvertebrate Sampling: Rocky-Bottom Streams Macroinvertebrate Sampling: Muddy-Bottom Streams 14.2.4 Postsampling Routine Sampling Devices 14.2.5 The Bottom Line on Biological Sampling 14.3 Water Quality Monitoring (Drinking Water) 14.3.1 Is the Water Good or Bad? 14.3.2 State Water Quality Standards Programs 14.3.3 Designing a Water Quality Monitoring Program 14.3.4 General Preparation and Sampling Considerations Method A: General Preparation of Sampling Containers Method B: Acid Wash Procedures 14.3.5 Sample Types 14.3.6 Collecting Samples from a Stream Whirl-pak® Bags Screw-Cap Bottles 14.3.7 Sample Preservation and Storage 14.3.8 Standardization of Methods 14.4 Test Methods (Drinking Water and Wastewater) 14.4.1 Titrimetric Methods 14.4.2 Colorimetric Methods 14.4.3 Visual Methods 14.4.4 Electronic Methods 14.4.5 Dissolved Oxygen Testing Sampling and Equipment Considerations Dissolved Oxygen Test Methods 14.4.6 Biochemical Oxygen Demand Testing Sampling Considerations BOD Sampling, Analysis, and Testing 14.4.7 Temperature Measurement Sampling and Equipment Considerations 14.4.8 Hardness Measurement Measuring Hardness 14.4.9 pH Measurement Analytical and Equipment Considerations pH Meters pH Pocket Pals and Color Comparators© 2003 by CRC Press LLC 14.4.10 Turbidity Measurement Sampling and Equipment Considerations Using a Secchi Disk Transparency Tube 14.4.11 Orthophosphate Measurement Forms of Phosphorus The Phosphorus Cycle Testing Phosphorus Sampling and Equipment Considerations Ascorbic Acid Method for Determining Orthophosphate 14.4.12 Nitrates Measurement Sampling and Equipment Considerations Cadmium Reduction Method Nitrate Electrode Method 14.4.13 Solids Measurement Solids Sampling and Equipment Considerations Total Suspended Solids Volatile Suspended Solids Testing 14.4.14 Conductivity Testing Sampling, Testing, and Equipment Considerations 14.4.15 Total Alkalinity Analytical and Equipment Considerations Burets, Titrators, and Digital Titrators for Measuring Alkalinity 14.4.16 Fecal Coliform Bacteria Testing Fecal Coliforms: General Information Fecal Coliforms Sampling Requirements Sampling and Equipment Considerations Fecal Coliform Testing 14.4.17 Apparent Color Testing/Analysis 14.4.18 Odor Analysis of Water 14.4.19 Chlorine Residual Testing/Analysis DPD-Spectrophotometric DPD-FAS Titration Titrimetric–Amperometric Direct Titration 14.4.20 Fluorides 14.5 Chapter Review Questions and Problems References Part IV Water and Water Treatment Chapter 15 Potable Water Sources 15.1 Introduction 15.1.1 Key Terms and DeÞnitions 15.1.2 Hydrologic Cycle 15.2 Sources of Water 15.3 Surface Water 15.3.1 Advantages and Disadvantages of Surface Water 15.3.2 Surface Water Hydrology 15.3.3 Raw Water Storage 15.3.4 Surface Water Intakes 15.3.5 Surface Water Screens 15.3.6 Surface Water Quality© 2003 by CRC Press LLC 15.4 Groundwater 15.4.1 Groundwater Quality 15.5 GUDISW 15.6 Surface Water Quality and Treatment Requirements 15.7 Public Water System Use Requirements 15.8 Well Systems 15.8.1 Well Site Requirements 15.8.2 Types of Wells Shallow Wells Deep Wells 15.8.3 Components of a Well Well Casing Grout Well Pad Sanitary Seal Well Screen Casing Vent Drop Pipe Miscellaneous Well Components 15.8.4 Well Evaluation 15.8.5 Well Pumps 15.8.6 Routine Operation and Record Keeping Requirements Well Log 15.8.7 Well Maintenance Troubleshooting Well Problems 15.8.8 Well Abandonment 15.9 Chapter Review Questions and Problems Reference Chapter 16 Watershed Protection 16.1 Introduction 16.2 Current Issues in Water Management 16.3 What is a Watershed? 16.4 Water Quality Impact 16.5 Watershed Protection and Regulations 16.6 A Watershed Protection Plan 16.7 Reservoir Management Practices 16.8 Watershed Management Practices 16.9 Chapter Review Questions and Problems Reference Chapter 17 Water Treatment Operations and Unit Processes 17.1 Introduction 17.2 Waterworks Operators 17.3 Purpose of Water Treatment 17.4 Stages of Water Treatment 17.5 Pretreatment 17.5.1 Aeration 17.5.2 Screening 17.5.3 Chemical Addition Chemical Solutions Chemical Feeders Chemical Feeder Calibration© 2003 by CRC Press LLC Iron and Manganese Removal Hardness Treatment Corrosion Control 17.6 Coagulation 17.6.1 Jar Testing Procedure 17.7 Flocculation 17.8 Sedimentation 17.9 Filtration 17.9.1 Types of Filter Technologies Slow Sand Filters Rapid Sand Filters Pressure Filter Systems Diatomaceous Earth Filters Direct Filtration Alternate Filters 17.9.2 Common Filter Problems 17.9.3 Filtration and Compliance with Turbidity Requirements (IESWTR) Regulatory Requirements Individual Filter Monitoring Reporting and Record Keeping Additional Compliance Issues 17.10 Disinfection 17.10.1 Need for Disinfection in Water Treatment. 17.10.2 Pathogens of Primary Concern Bacteria Viruses Protozoa 17.10.3 Recent Waterborne Outbreaks E. coli Giardia lamblia Cryptosporidium Legionella pneumophila 17.10.4 Mechanism of Pathogen Inactivation 17.10.5 Other Uses of Disinfectants in Water Treatment Minimization of DBP Formation Control of Nuisance Asiatic Clams and Zebra Mussels Oxidation of Iron and Manganese Prevention of Regrowth in the Distribution System and Maintenance of Biological Stability Removal of Taste and Odors through Chemical Oxidation Improvement of Coagulation and Filtration EfÞciency Prevention of Algal Growth in Sedimentation Basins and Filters Removal of Color 17.10.6 Types of DBPs and Disinfection Residuals Disinfection By-Product Formation DBP Control Strategies CT Factor 17.10.7 Pathogen Inactivation vs. DBP Formation 17.10.8 Disinfectant Residual Regulatory Requirements 17.10.9 Summary of Current National Disinfection Practices 17.10.10 Summary of Methods of Disinfection 17.10.11 Chlorination Chlorine Terms Chlorine Chemistry Breakpoint Chlorination© 2003 by CRC Press LLC Gas Chlorination Hypochlorination Determining Chlorine Dosage Chlorine Generation Primary Uses and Points of Application of Chlorine Factors Affecting Chlorination Measuring Chlorine Residual Pathogen Inactivation and Disinfection EfÞcacy Disinfection By-Products Operational Considerations Advantages and Disadvantagesof Chlorine Use Chlorine Summary Table 17.11 Arsenic Removal from Drinking Water 17.11.1 Arsenic and Water 17.11.2 Arsenic Removal Technologies Prescriptive Processes Adsorptive Processes Membrane Processes Alternative Technologies 17.12 Who is Ultimately Responsible for Drinking Water Quality? 17.13 Chapter Review Questions and Problems References Chapter 18 Wastewater Treatment 18.1 Wastewater Operators 18.1.1 The Wastewater Treatment Process: The Model 18.2 Wastewater Terminology and DeÞnitions 18.2.1 Terminology and DeÞnitions 18.3 Measuring Plant Performance 18.3.1 Plant Performance and EfÞciency 18.3.2 Unit Process Performance and EfÞciency 18.3.3 Percent Volatile Matter Reduction in Sludge 18.4 Hydraulic Detention Time 18.4.1 Detention Time in Days 18.4.2 Detention Time in Hours 18.4.3 Detention Time in Minutes 18.5 Wastewater Sources and Characteristics 18.5.1 Wastewater Sources Generation of Wastewater 18.5.2 ClassiÞcation of Wastewater 18.5.3 Wastewater Characteristics Physical Characteristics Chemical Characteristics Biological Characteristics and Processes 18.6 Wastewater Collection Systems 18.6.1 Gravity Collection System 18.6.2 Force Main Collection System 18.6.3 Vacuum System 18.6.4 Pumping Stations Wet Well–Dry Well Pumping Stations Wet Well Pumping Stations Pneumatic Pumping Stations Pumping Station Wet Well Calculations© 2003 by CRC Press LLC 18.7 Preliminary Treatment 18.7.1 Screening Manually Cleaned Screens Mechanically Cleaned Screens Safety Screenings Removal Computations 18.7.2 Shredding Comminution Barminution 18.7.3 Grit Removal Gravity and Velocity Controlled Grit Removal Grit Removal Calculations 18.7.4 Preaeration Operational Observations, Problems, and Troubleshooting 18.7.5 Chemical Addition Operational Observations, Problems, and Troubleshooting 18.7.6 Equalization Operational Observations, Problems, andTroubleshooting 18.7.7 Aerated Systems 18.7.8 Cyclone Degritter 18.7.9 Preliminary Treatment Sampling and Testing 18.7.10 Other Preliminary Treatment Process Control Calculations 18.8 Primary Treatment (Sedimentation) 18.8.1 Process Description Overview of Primary Treatment 18.8.2 Types of Sedimentation Tanks Septic Tanks Two-Story (Imhoff) Tank Plain Settling Tanks (ClariÞers) 18.8.3 Operator Observations, Process Problems, and Troubleshooting Primary ClariÞcation: Normal Operation Primary ClariÞcation: Operational Parameters (Normal Observations) 18.8.4 Process Control Calculations Percent Removal Detention Time Surface Loading Rate (Surface Settling Rate and Surface Overßow Rate) Weir Overßow Rate (Weir Loading Rate) Sludge Pumping BOD and Suspended Solids Removal 18.8.5 Problem Analysis 18.8.6 Efßuent from Settling Tanks 18.9 Secondary Treatment 18.9.1 Treatment Ponds Types of Ponds Process Control Calculations (Stabilization Ponds) 18.9.2 Trickling Filters Trickling Filter DeÞnitions Trickling Filter Equipment Filter ClassiÞcations Standard Operating Procedures General Process Description Operator Observations, Process Problems, and Troubleshooting Process Calculations© 2003 by CRC Press LLC 18.9.3 Rotating Biological Contactors RBC Equipment RBC Operation RBC: Expected Performance Operator Observations, Process Problems, and Troubleshooting RBC: Process Control Calculations 18.10 Activated Sludge 18.10.1 Activated Sludge Terminology 18.10.2 Activated Sludge Process: Equipment Aeration Tank Aeration Settling Tank Return Sludge Waste Sludge 18.10.3 Overview of Activated Sludge Process 18.10.4 Activated Sludge Process: Factors Affecting Operation Growth Curve 18.10.5 Activated Sludge Formation 18.10.6 Activated Sludge: Performance-Controlling Factors Aeration Alkalinity Nutrients pH Temperature Toxicity Hydraulic Loading Organic Loading 18.10.7 Activated Sludge ModiÞcations Conventional Activated Sludge Step Aeration Complete Mix Pure Oxygen Contact Stabilization Extended Aeration Oxidation Ditch 18.10.8 Activated Sludge: Process Control Parameters Alkalinity Dissolved Oxygen pH Mixed Liquor Suspended Solids, Mixed Liquor Volatile Suspended Solids, and Mixed Liquor Total Suspended Solids Return Activated Sludge Rate and Concentration Waste Activated Sludge Flow Rate Temperature Sludge Blanket Depth 18.10.9 Operational Control Levels Inßuent Characteristics Industrial Contributions Process Sidestreams Seasonal Variations Control Levels at Start-Up 18.10.10 Operator Observations: Inßuent and Aeration Tank Visual Indicators: Inßuent and Aeration Tank Final Settling Tank (ClariÞer) Observations© 2003 by CRC Press LLC 18.10.11 Process Control Testing and Sampling Aeration Inßuent Sampling Aeration Tank Settling Tank Inßuent Settling Tank Settling Tank Efßuent Return Activated Sludge and Waste Activated Sludge 18.10.12 Process Control Adjustments 18.10.13 Troubleshooting Operational Problems 18.10.14 Process Control Calculations Settled Sludge Volume Estimated Return Rate Sludge Volume Index Waste Activated Sludge Food to Microorganism Ratio (F:M Ratio) Mean Cell Residence Time (MCRT) Mass Balance 18.10.15 Solids Concentration: Secondary ClariÞer 18.10.16 Activated Sludge Process Record Keeping Requirements 18.11 Disinfection of Wastewater 18.11.1 Chlorine Disinfection Chlorination Terminology Wastewater Chlorination: Facts and Process Description Chlorination Equipment Chlorination: Operation Troubleshooting Operational Problems Dechlorination Chlorination Environmental Hazards and Safety Chlorine: Safe Work Practice Chlorination Process Calculations 18.11.2 UV Irradiation 18.11.3 Ozonation 18.11.4 Bromine Chloride 18.11.5 No Disinfection 18.12 Advanced Wastewater Treatment 18.12.1 Chemical Treatment Operation, Observation, and Troubleshooting Procedures 18.12.2 Microscreening Operation, Observation, and Troubleshooting Procedures 18.12.3 Filtration Filtration Process Description Operation, Observation, and Troubleshooting Procedures 18.12.4 Biological NitriÞcation Operation, Observation, and Troubleshooting Procedures 18.12.5 Biological Denitrifcation Observation, Operation, and Troubleshooting Procedures 18.12.6 Carbon Adsorption Operation, Observation, and Troubleshooting Procedures 18.12.7 Land Application Types or Modes of Land Application 18.12.8 Biological Nutrient Removal 18.13 Solids (Sludge or Biosolids) Handling 18.13.1 Sludge: Background Information Sources of Sludge Sludge Characteristics© 2003 by CRC Press LLC Sludge Pumping Calculations Sludge Treatment: An Overview 18.13.2 Sludge Thickening Gravity Thickening Flotation Thickening Solids Concentrators 18.13.3 Sludge Stabilization Aerobic Digestion Anaerobic Digestion Other Sludge Stabilization Processes 18.13.4 Sludge Dewatering Sand Drying Beds Rotary Vacuum Filtration Pressure Filtration Centrifugation Sludge Incineration Land Application of Biosolids 18.14 Permits, Records, and Reports 18.14.1 DeÞnitions 18.14.2 NPDES Permits Reporting Sampling and Testing Efßuent Limitations Compliance Schedules Special Conditions Licensed Operator Requirements Chlorination or Dechlorination Reporting Reporting Calculations 18.15 Chapter Review Questions and Problems References Appendix A Answers to Chapter Review Questions and Problems Appendix B Formulae© 2003 by CRC Press LLC PART I Water and Wastewater Operations: An Overview© 2003 by CRC Press LLC Problems Facing Water and Wastewater Treatment Operations What is of all things most yielding, Can overcome that which is most hard, Being substanceless, it can enter in even where there is no crevice. That is how I know the value of action which is actionless. Lao Tzu, 5th Century B.C. 1.1 INTRODUCTION Although not often thought of as a commodity (or, for that matter, not thought about at all), water is a commodity — a very valuable commodity. In this text, it is our position that with the passage of time, potable water will become even more valuable. Moreover, with the passage of even more time, potable water will be even more valuable than we might imagine. It may be possibly comparable in pric- ing, gallon for gallon, to what we pay for gasoline, or even more. Earth was originally allotted a finite amount of water — we have no more or no less than that original allotment today. It logically follows that, in order to sustain life as we know it, we must do everything we can to preserve and protect our water supply. We also must purify and reuse the water we presently waste (i.e., wastewater). 1.2 THE PARADIGM SHIFT Historically, the purpose of water supply systems has been to provide pleasant drinking water that is free of disease organisms and toxic substances. In addition, the purpose of wastewater treatment has been to protect the health and well being of our communities. Water and wastewater treatment operations have accomplished this goal by (1) prevention of disease and nuisance conditions; (2) avoidance of contaminatio

Các file đính kèm theo tài liệu này:

  • pdfWater & Wastewater Treatment Plant Operations_HB_Frank R[1]..pdf