AWWA M24-2009 Planning for the Distribution of Reclaimed Water.pdf

Planning for the Distribution of Reclaimed Water

AWWA MANUAL M24 Third Edition

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

MANUAL OF WATER SUPPLY PRACTICES — M24, Third Edition

Planning for the Distribution of Reclaimed Water Copyright © 1983, 1994, 2009 American Water Works Association All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information or retrieval system, except in the form of brief excerpts or quotations for review purposes, wi thout the written permission of the publisher. Disclaimer The authors, contributors, editors, and publisher do not assume responsibility for the validity of the content or any consequences of their use. In no event will AWWA be liable for direct, indirect, special, incidental, or consequential damages arising out of the use of information presented in this book. In particular, AWWA will not be responsible for any costs, including, but not l imited to, those incurred as a result of lost revenue. In no event shall AWWA’s liability exceed the amount paid for the purchase of this book.

Project Manager/Technical Editor: Melissa Valentine Production Editor: Cheryl Armstrong Manuals Coordinator: Beth Behner

Library of Congress Cataloging-in-Publication Data

Planning for the distribution of reclaimed water. – 3rd ed. p. cm. – (Manual of water supply practices; M24) Includes bibliographical referencesand index. ISBN 978-1-58321-726-9 1. Water reuse. I. American Water Works Association. ` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

TD429.P556 2009 628.1’62–dc22 2009002142

Printed in the United States of America American Water Works Association 6666 West Quincy Ave. Denver, CO 80235 Printed on recycled paper

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Contents List of Figures, v List of Tables, vii Preface, ix Acknowledgments, xi Dedication, xiii

Chapter 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Definitions, 1 History, 2 Potential Drivers for Dual Distribution Systems, 3 Sources of Nonpotable Water, 5 Potential Uses for Nonpotable Water, 5 Nonpotable-Water Reuse Legislation, 6 References, 8 Chapter 2 Water Reuse Regulations and Guidelines . . . . . . . . . . . . . . . . . . . 9 Existing State Regulations, 10 Treatment, Quality, and Monitoring Equipment, 13 References, 28 Chapter 3 Planning . .. . .. . .. .. . .. . .. . .. .. . .. . .. . .. .. . .. . .. . .. .. . .. 3 1 General Planning Concepts, 31

Reclaimed-Water 34 Reclaimed-Water Supply, System Types, 42 Development of Distribution System Options, 44 Implementation, 45 Conclusions, 46 References, 47 Chapter 4 Engineering Design — Treatment . . . . . . . . . . . . . . . . . . . . . . . . . 49 Sources, 49 Wastewater, 49 Supply Variations, 50 Treatment for Reclaimed Water, 52 References, 55 Chapter 5 Engineering Design — Distribution . . . . . . . . . . . . . . . . . . . . . . . 57 Demand Management, 57 System Hydraulic Modeling, 58 Design Components, 59

Storage, 62 Safeguards, 66 References, 72

iii --`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Chapter 6 Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3 Introduction, 73 Management Philosophy, 73 Protecting Public Health, 74 System Policies and Procedures, 77 Developing the Nonpotable Infrastructure, 79 Understanding Customer Needs and Requirements, 82 Establishing a Viable Customer Base, 85 Service Connections, 85 System Operations and Maintenance, 87 Reference, 89 Chapter 7 Financial/Economic Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Overview, 91 Economic Factors, 91 Institutional Issues, 97 References, 98 Index, 99 List of AWWA Manuals, 103

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

iv

Not for Resale

Figures

Figure 1-1

El Tovar Lodge in Grand Canyon Village, Ariz. . . . . . . . . . . . . . . . . . . . . . . . . . 2

Figure 1-2

Crop irrigation with reclaimed water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Figure 1-3

Irrigation with reclaimed water at a North Carolina golf course . . . . . . . . . . 6

Figure 1-4

Firefighter using reclaimed water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 3-1

Centralized reclamation facility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 3-2

Decentralized (satellite) reclamation facility . . . . . . . . . . . . . . . . . . . . . . . . . 35

Figure 3-3

Cedar Bay Power Plant (Jacksonville, Fla.) is provided reclaimed water for cooling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 3-4

Dual distribution system for a new community . . . . . . . . . . . . . . . . . . . . . . . 44

Figure 4-1

Potable- and nonpotable-water use—monthly historic demand variation, St. Petersburg, Fla.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Figure 4-2

Satellite reclamation plant in residential area . . . . . . . . . . . . . . . . . . . . . . . . . 54

Figure 5-1

Purple pipes for reclaimed-water distribution system . . . . . . . . . . . . . . . . . . 60

Figure 5-2 Figure 5-3

Line tap into reclaimed-water line. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Reclaimed-water meter box. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Figure 5-4

Reclaimed-water valve box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Figure 5-5

St. Petersburg, Fla., reclamation plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Figure 5-6

Storage tank for reclaimed water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Figure 5-7

Backflow-prevention device between reclaimed water and alternative source of nonpotable water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Figure 5-8

Neighborhood sign noting use of reclaimed water . . . . . . . . . . . . . . . . . . . . 68

Figure 5-9

Notice of use of reclaimed water by facility . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 5-10

Typical urban utility pipe separations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6-1

Cemetery watered with reclaimed water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Figure 6-2

A baseball field maintained with reclaimed water . . . . . . . . . . . . . . . . . . . . . 84

Figure 6-3

Xeriscape watered with reclaimed water at a high school . . . . . . . . . . . . . . 84

Figure 7-1

Water reuse marketing mix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Figure 7-2

Creating a water reuse market. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 --`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

v

Not for Resale

70

This page intentionally blank.

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Tables

Table 2-1

Uses of reclaimed water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 0

Table 2-2

Summary of state reuse regulations and guidelines for nonpotable reuse applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 1

Table 2-3

Number of states with regulations or guidelines for each type of nonpotable-water reuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 3

Table 2-4

Examples of State Water Reuse Criteria for Selected Nonpotable Applications............................................15

Table 2-5

USEPA suggested guidelines for nonpotable reuse of municipal wastewater . . . .. . . . . . .. . . . . .. . . . . . .. . . . . .. . . . . . .. . . . . .. . .2 3

Table 3-1

Typical survey form to ascertain interest in water reuse . . . . . . . . . . . . . . . . .33

Table 3-2

Urban water demand categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 7

Table 3-3

Urban water demands as a percentage of average daily use . . . . . . . . . . . . . .38

Table 3-5

Potential reuse demands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 9

Table 5-1

Projected reuse demands for Raleigh, N.C., reclaimed-water system. . . . . . . 58

Table 5-2 Table 6-1

Utility separation regulations and standards from various states . . . . . . . . . . 71 Attributes and management requirements for typical reclaimed-water applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 4

Table 6-2

Guidelines for workers’ safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 8

vii Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

This page intentionally blank.

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Preface This publication is the second revision of the srcinal AWWA Manual M24, Dual Water Systems, published in 1983. The title has been changed to Planning for the Distribution of Reclaimed Water to better represent the content of the manual. The manual provides information on the planning and design of dual distribution systems for properly treated reclaimed water (nonpotable water) for applications that do not require potable-quality water. The distribution of reclaimed water through the use of dual water distribution systems, one for potable water and the other for nonpotable water, is becoming an accepted practice. The main reasons for this are diminishing supplies of high-quality water resources, rapidly escalating costs for developing new sources or for treating poor-quality water to potable-water standards, and the increasing costs involved in discharging wastewater to the environment. When faced with the task of developing additional water sources, community water utility managers and design engineers are increasingly evaluating the potential for distributing reclaimed water to serve their community’s needs. Developing a reclaimed-water distribution system may be less costly and less wasteful than existing practices that use potable water for purposes that do not require high-quality water. Properly treated and distributed nonpotable water, as defined herein, can safely be used for irrigation, industrial applications, and a wide range of other nonpotable urban purposes, including toilet flushing in high-rise commercial and residential buildings. These practices conserve limited high-quality water for drinking, cooking, and other uses requiring potable water. Although several states have established regulations for the distribution and use of nonpotable water, national standards (although there are guidelines) have not been established. The AWWA Water Reuse Committee, which prepared this manual, provides this information for water systems wishing to distribute reclaimed water. Water utilities should consult state and local regulatory agencies before designing a nonpotable water distribution system. State and local regulations may impose requirements differing from the recommendations in this manual. These requirements must be followed to ensure system compliance.

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

ix Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

This page intentionally blank.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Acknowledgments This third edition of the AWWA Manual M24 Planning for the Distribution of Reclaimed Water was prepared by members of the Water Reuse Committee of the AWWA Water Resources and Sustainability Division. Alan Rimer of Black & Veatch and Daniel Okun, Professor Emeritus of the University of North Carolina at Chapel Hill served as coeditors. There wer e many contributors to this manual. Some wrote full sections, while others contribute d extensively by providing materials for the manual and/or through their thorough review of the document. Specifically, the following were primarily responsible for various chapters of the manual: Chapter 1—Dr. Dan Okun , UNC CH (retired), Chapel Hill, N.C. Chapter 2— Dr. James Crook , Environmental Engineering Consultant, Norwell, Mass. Chapters 3 and 6— Dr. Alan Rime r, Black & Veatch, Cary, N.C. Chapter 4— Don Vandertulip , CDM, San A ntonio, Texas Chapter 5— Andy Richardson, Greeley and Hansen LLC, Phoe nix, Ar iz. David Ammerman, Lee Cesario, and Craig Riley provided a wealth of new information. Fred Bloetscher, Lee Cesario, John Morris, Craig Riley, Adriano Vieira, and Gary Yamamoto supplied ex cellent editorial guidance on t he final document. AWWA sta ff, including Bill Lauer and Beth Behner, was in strumental in mov ing th is publication a long and providing editorial gu idance. Others who participated in the continuing rev iew process inclu ded Timothy Bosetti, Jim Cathcar t, Kev in Conway, Dan iel Horne, and Toby Roy. A special thank s to Jim Crook and Gary Grinnell, past Chairs of the Water Reuse Committee when this revision of the manual began and who provided the srcinal impetus to begin the revisions. This manual was reviewed and approved in 2004 by the Water Reuse Committee, which at the time had the following personnel. Committee members are listed with current affiliations (2009) unless otherwise requested. James Crook , Chair Gary K. Grinnell , Vice Chair R.E. Adamski , Gannett Fleming Inc., Locust Valley, N.Y. J.T. Aguinal do, Doosan Hydro Technology, Tampa, Fla. Carolyn Ahrens Wieland , Booth, Ahrens & Werkenthin P.C., Austin, Texas Walter Backstrom , Woodinville, Wash. C.D. Baker , The Subsidence District, F riendswood, Te xas Rober t Bandarra , Sr., HDR Engineering Inc., Bellevue, Wash. J.R. Bratby, Brown and Ca ldwell, Centennial, Colo. Phil Carter, City of Greeley, Water and Sewer, Greeley, Colo. Brad Ca stleberry, Lloyd, Gosselink, et al., Austin, Texas V.K. Chaudhr y, Delhi, India James Crook , Norwell, Mass. Shivaji Deshmukh , Orange County Water District, Fountain Valley, Cali f. K.N. DiNata le, DiNatale Water Consultants Inc., Boulder, Colo. J.D. Edwards Water Department, Austin,Las Texas G.K. Grinnell ,, Austin Las Vegas Valley Water District, Vegas, Nev. G.C. Harrell, Woodinville Water District, Woodinville, Wash. P.M. Hecht , CH2M Hil l, Newport News, Va. D.J. Henrich sen , HDR Engineering Inc., Minneapolis, Minn.

xi --`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

T.R. Holliman, Associated Engineers Inc., Chino Hills, Cali f. Sarah Holmgren , Montgomery Watson, Walnut Creek, Calif. D.B. Horne, Virgi nia Departm aent of Health, Office of Dri nking Water, Norfolk, Va. Jo Ann Jackson , Post Buckley Schuh & Jernigan Inc., Winter Park, Fla. F.J. Johns, Tetra Tech EC Inc., Lakewood, Colo. L.J. Johnson, East Bay Municipal U tility District, Oakl and, Calif. Christine Kirchhoff , Ann Arbor, Mich. W.C. Lauer, American Water Works Association, Denver, Colo. J.A. Mele , ADS Envi ronmental, Cream Ridge, N.J. L.K. Moody , American Water Works Association, Denver, Colo. J.T. Morris, Morris Water Resources , San M arino, Cali f. W.L. Nero, CH2M Hill, Orlando, Fla. D.A. Okun , Carrboro, N.C. Patric ia Renaud , Suez Environment Dore-Cirsee, Le Pecq, Fra nce C.L. Riley , Washington State Depart ment of Health, Spokane, W ash. A.E. Rime r, Black & Veatch, Cary, N.C. T.G. Sand s, Salt River Project, Phoe nix, Ar iz. R.E. Schenk, Camp Dresser & McKee Inc., Austin, Texas Steve Setoodeh , El Dorado Irrigation District, Placerville, Calif. T.R. Slifk o, Los A ngeles County Sanitation Distr ict, Whittier, Calif. K.A. T hompson, CH2M Hil l, Englewood, Colo . A.J. von Gottberg, Koch Membrane Systems Inc., Cambridge, Mass. Ken Weinberg , San Diego County Water Authority, San Diego, Calif. D.W. York, Tallahassee, Fla.

This m anual was developed under the guidance of the Water Resource Sustainability Division (formerly the Water Resources Division), which included the following personnel at the time of approval (2008): Frederick Bloet scher, Chair Carolyn Ahrens Wieland , Booth, Ahrens & Werkenthin P.C., Austin, Texas Kimberly Ajy, River to Tap, Roswell, Ga. Frederick Bloet scher, Florida Atla ntic University, Hollywood, Fla . J.A. Cathcart , HDR Engineering Inc., Irvi ne, Calif. A.D. Deiste r, Brown and Caldwell Environmental Engineers, Rancho Cordova,

Calif. R.W. Gul lick , Environmental Eng ineering & Technology, Berlin, N.J. Elise Harr ington , American Water Works Association, Denver, Colo. J.W. Miller, Everett Public Works Dept., Everett, Wash. L.K. Moody , American Water Works Association, Denver, Colo. M.P. Robinson, Jr., Malcolm Pi rnie Inc., Newport News, Va.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

xii

Not for Resale

Dedication AWWA Manua l M24, Planning for the Distribution of Recl aimed Water, is dedicated to Dr. Daniel A. Okun, University of North Carolina at Chapel Hill, Kenan professor of environmental engineering. For several decades, Dr. Okun was a leading advocate for the use of reclaimed water and the development of dual distribution systems to convey that water. Dr. Okun advanced the engineering of such systems by advocating for their planning in the ea rly stages of the development of new communities and their expansion into existing communities. He suggested new design concepts, new piping materials, and the broader use of reclaimed water, including for fire protection for communities. The engineering community and all those whom Dr. Okun worked with or taught are far better engineers because of his lasti ng influence.

The late Professor Emeritus Dr. Daniel A. Okun

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

xiii

Not for Resale

This page intentionally blank.

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

AWWA MANUAL

Chapter

M24

1 Introduction Since 1983, when the fir st edition of this American Water Works Association (AWWA) manual was published, many water and wastewater facilities, communities, authorities, states, and countries have implemented dual water distribution systems, along with reclaiming wastewater to make the most of all their available water resources. The International Water Association in London lists, in addition to the United States, Australia, and the United Kingdom, 13 other countries that have strong programs in dual water distr ibution and water reclamation. All qua ntitative efforts to assess t he growth of water reclamation and the adoption of dual water d istribution systems for communities large and smal l have been difficult tasks a s their growth seems to be almost exponential. What is appreciated, almost worldwide, is that wastewater reclamation and dual water distribution systems are an important consideration for communities as they search to expand their water supply resource(s). This manual discusses the planning, design, construction, operation, regulatory framework, and m anagement of community dual water di stribution systems, which consist of separate systems for distributing potable water and nonpotable water principally drawn from reclaimed wastewater.

DEFINITIONS ______________________________________________ •

Reclaimed water: Wastewater that has been treated and recovered for useful

purposes. •

Potable water: Water that is safe and satisfactory for drinking and cooking.

•

Nonpotable Water: Water that may contain objectionable pollution, contami-

nation, minerals, or infective agents and is considered unsafe, unpalatable, or both for drinking. •

Dual distribution systems: Two separate water piping systems distributing

water to customers, one carrying potable water and the other conveying lesser-quality water (e.g., nonpotable reclaimed water) for reuse purposes.

1 Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

--`,,```,,,,````-`-`,,`,,`,`,,`---

2

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

HISTORY __________________________________________________ The concept of dual systems is not new, having been adopted by Augustus about 2,000 years ago. Water from one of the hills near Rome was found to be h ighly poisonous, but it was still used to feed the many fountains of Rome and for many other nonpotable uses. In 1911, W.T. Sedgwick of the Massachusetts Institute of Technology read a paper to the New England Water Works Association titled “Has the Time Come for Double Municipal Water Supplies, One—Naturally Pu re—for Drinking and Cooking, the Other—Denatured or Sterilized—for All Other Purposes?” (Sedgwick 1911). This was the advent of the period when dual distribution was at least recognized. The basis of the adoption of water reclamation and dual distribution systems stands on a firm foundation dating back to the late 1950s. The policy affirming this approach was enunciated by the United Nations Economic and Social Council, which stated, “No higher quality water, unless there is a surplus of it, should be used for a purpose that can tolerate a lower grade” (United Nations Economic and Social Council 1958). For public drinki ng supplies, it is AWW A’s policy that the highest qual ity sources be used (Dr inking Water Quality Statement of Policy adopted by the AWWA Board of Directors Jan. 24, 1988, revised Jan. 29, 1989, Jan. 23, 2000, June 15, 2003, and Jan. 21, 2007). With increasing populations and urban and industrial development throughout the world and with most high-qual ity sources of substantial yield already develope d, surpluses of high-qual ity water for the future are becoming exhausted. Using wastewater treatment plant effluents for industrial, urban, or agr icultural irr igation purposes is one way a nonpotable supply can lessen the demand on potable water. An example is the introduction of wastewater treatmen t plant effluent fo r use in the steel industry in Baltimore, Md., almost a century ago (Okun 1973). Another example is the distribution of reclaimed wastewater to several industries in Colorado Springs, Colo., in 1960, to relieve the demand on limited freshwater resources. Substitution of lower quality water for nonpotable purposes to preserve limited resources of high quality water remains one of the primary purposes of dual distribution systems. For example, seawater has been used extensively for decades for toilet flushing in commercial and multifam ily residential buildings in Hong Kong to preserve limited freshwater resources.

Figure 1-1 El Tovar Lodge in Grand Canyon Village, Ariz.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

INTRODUCTION

3

Figure 1-2 Crop irrigation with reclaimed water

The first dual distribution system illustrating the potential for the future was built in 1926, for the Grand Canyon Village in Arizona, which is on the south rim of the Grand Canyon and had become a fast growing community with the El Tovar Lodge at the center (Figure 1-1). The village had v irtual ly no rainfall, and water had to be carried by trai n and other vehicles. In 1926, a source of the fresh water was found above the Colorado River, which was pumped to the village to serve a hotel and all the other services. Recognizing that the resulting treated wastewater produced in the village might be applied usefully, these treated wastewaters were circulated in a reclaimed water distribution system, thus srcinating the fir st purposeful water reclamation system and dual distribution system in the United States. In the 1950s, at meetings of the National Research Council’s committee on sanitary engineering and the environment, Gordon M. Fair of Harvard suggested dual water supplies. In 1965, Paul Haney enhanced the idea in the first published art icle on dual systems. These were the two most w idely circulated publications enco uraging the construction of dual systems. Two factors have accelerated the development of dual distribution systems. First is the need for water supplies that do not necessarily need to be of potable quality for urban and industrial use. Second are new requirements fo r costly, advanced wastewater treatment, including nutrient and organics removal, to protect receiving waters. Using reclaimed water for nonpotable purposes may reduce treatment costs when nutrient removal is not only unnecessary but wasteful. This is the case for urb an and agricultural irrigation because nutrients already in the wastewater can replace those that would ordinarily need to be added (Figure 1-2). An extensive distr ibution system f or urban irr igation, including the watering of parks, campuses, median strips, and residential lawns, is an importa nt element of a reclaimed-water system used for other nonpotable purposes.

POTENTIAL DRIVERS FOR DUAL DISTRIBUTION SYSTEMS ________ With many successful dual water di stribution systems now in operation, ranging from systems that serve only one or two major customers to systems that serve most a ll properties in a community, water supply professi onals a re now considering dual d istribution systems for addressing water supply needs, water pollution-control problems, or both. Reclaimed

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

4

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

water is the “new” water resource. There are many drivers that a community will consider when developing a plan for assessing the feasibility of dual distribution. Such drivers range from conservation to l imited water resources.

Conservation Before any concerted effort is made to find additional water resources for a community, or to build costly dual distribution systems, conservation of water often is the utility’s first approach to reduce water consumption. Wasteful water practices, such as the use of old-style, high-volume flush toilets, or nonwater-conserving shower heads and other appliances, and inefficient local landscaping practices, must be carefu lly examined by the utility and its customers. Communities have had varying degrees of success in reducing water consumption through conservation practices, but conservation has good “first line of defense.”

proven to be a

Limited Water Resources Competition for existing water resources or limitations on these resources often make acquisition of additional water resources po litically and fi nancially di fficult. For example, obtaining additional water resources m ight require interbasin (raw water ) transfer, which is currently less politically acceptable than it was in the earlier years of water resources development. The specter of climate change and its potential implications for urban water utilities has added i nto this mi x of uncertainty. Consideratio n must also be given to downstream users impacted by water rights issues a nd stream flows where applicable . Greater knowledge of groundwater hydrology has illuminated the concerns associated with excessive withdrawals from aquifers, which result in i ncreasing costs of pumping, impaired water quality, and land subsidence. Limited resources create a situation in which water reclamation and a dual di stribution system may becom e attractive.

Limited Water Supplies ` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

When demand is expected to exceed the yield from existing water supply facilities, and additional facilities need to be constructed, the gradual introduction of a nonpotable system might be appropriate. Water users, whether industrial, commercial, or municipal, may well be served with reclaimed wastewater in place of potable water at a cost substantially lower than the cost of developing new high-quality sources of supply for potable purposes.

Polluted Sources The 1962 US Public Health Service Drinking Water Standards recommended that “water supply should be obtained from the most desirable source which is feasible” (USPHS 1962). US Environmental Protection Agency (USEP A) National Interim Pri mary Drinki ng Water Regulations adopted in 1975 state that “priority should be given to the selection of the purest source.” Many commun ities have selected the highest- quality source available, and additional develop ment may require use of a lesser quality source. In the past, engineers believed that they could render most polluted water safe for potable supply through adequate treatment, generally consisting of coagulation, fi ltration, and disinfection. Howeve r, the chemical revolution following World War II resulted in the creation of thousands of synthetic organic chemicals that are not readily degraded in the environment or easily treated. The number of contaminants regulated i n potable water has grown from 4 in 1925 to 93 primar y and secondary i n 2006 with more regulations anticipated. The treatmen t of water that will meet drinking water standards in the future will cost considerably more than it currently does. Degraded sources may therefore be less suitable for potable-water supplies but well-suited for one or more nonpotable purposes.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

INTRODUCTION

5

Rigorous Wastewater Treatment To restore and preserve the quality of North American waters, treatment requirements for municipal and industrial wastewaters have become increasingly stringent and costly. In many cases, nutrients may need to be removed. If the wastewater can be used in industry or for urban ir rigation, some advanced treatment, including nutrient rem oval, may not be necessary and may in fact be undesirable. The operation and maintenance of advanced physical and chemical wastewater treatment facilities are generally more costly than treatment for nonpotable reuse. If wastewater can be used productively, the savings in wastewater treatment can be passed on to users, making water reclamation and dual distribution systems more economically attra ctive.

SOURCES OF NONPOTABLE WATER___________________________ The most commonly used source of nonpotabl e water is water reclaimed f rom local wastewater treatment plants. The technology needed to assure the required quality is well established. Treatment of secondary effluent is accomplished by coagulation, conventional filtration, and d isinfection. Other sources for nonpotab le water include brackish or m ineralized surface waters and groundwaters, including seawater, certain industrial wastewaters, stormwater runoff, pollu ted natural waters, a nd irrigation return flows.

POTENTIAL USES FOR NONPOTABLE WATER ___________________ A dual d istr ibution system is most appropr iate when the nonpotable water can be used in a community. Some examples include the following: Public uses •

•

•

Park irrigation and water amenities, such as ornamental fountains School campus landscaping and playground irrigation, median strips, and roadway right-of-way landscaping irrigation Recreational facilities, such as golf course irrigation (Figure 1-3), tenniscourt wetting and washing

•

Cemeteries and nurseries

•

Firefighting (Figure 1-4)

•

Toilet and urinal flushing

Industrial and commercial uses

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

•

Cooling-tower makeup water

•

Boiler feedwater makeup water

•

Stack gas scrubbers

•

Process waters

•

Crop irrigation

•

Construction, including concrete manufacture, soil compaction, and dust control

•

Toilet and urinal flushing

•

Cleaning and car washing

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

6

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Figure 1-3 Irrigation with reclaimed water at a North Carolina golf course

Figure 1-4 Firefighter using reclaimed water

Residential uses •

Lawn watering

•

Toilet flushing (in many states)

NONPOTABLE-WATER REUSE LEGISLATION ____________________ In some states, such as California, Florida, A rizona, and North Carolina , nonpotable-water reuse is stimulated th rough legislation. The follo wing parag raphs provide an introduction to the history of such legislation.

California California has long recognized the benefits associated with reclaimed-water reuse. The state legislature declared that a substantial portion of future water requirements can be met state economically through the beneficial of reclaimed water. The legislature intends for the to undertake all possible stepsuse to encourage development of water-reclamation facilities so that reclai med water may be made avai lable to help meet California’s growing water requirements. Statutes added since 1973 prohibit the use of water from any suitable potable-water source for the irrigation of greenbelt areas, including golf courses,

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

INTRODUCTION

7

cemeteries, parks, and hig hway landscaped areas, when suitable reclaimed water is available. Additional uses have been added through subsequent legislation. Reclaimed water is considered suitable under the following conditions: •

•

•

•

The reclaimed-water source is of adequate quality for such use and is available; The reclaimed water may be provided to such greenbelt areas at a reasonable cost; Reclaimed-water use will not be detrimental to public health; Reclaimed-water use will not affect downstream water rights, will not degrade water quality, and is determined not to be injurious to plant life.

During the last 20 years, wastewater reclamation has been encouraged further by the Office of Water Recycling (OWR), a division of the California State Water Resources Control Board. OWR promotes treated wastewater reuse, identifies potential projects, and provides financia l assistance with water reuse projects.

Florida Although rainfa ll averages approximately 50 in. (130 cm) per year in Florida, potable-water resources are limited. The Florida Depar tment of Environmental Regulation has declared as policy that the state wi ll “advocate and direct the reuse of reclaimed water as a n integral part of water management programs ... consistent with protection of the public health and groundwater quality” and “encourage the use of water of the lowest acceptable quality for the purpose intended” (Florida Administrative Code 1988). This policy is expressed in the rules of the Southwest Florida Water Management District that state “before a consumptive use permit (for water abstraction) is issued, consideration will be given to the lowest quality water which the applicant can use, (and if) such water is available, the consumptive use permit will be issued only for the use of the lower quality water” (Southwest Florida Man agement Distr ict 1985).

Arizona Groundwater overdraft has lowered water levels by as much as 400 ft (122 m), resulting in increased pumping costs, degraded water quality, and land subsidence. The use of reclaimed water in Arizona is encouraged through several state laws. These laws resulted from a number of historical events. In 1948, the US Secretary of Interior advised A rizona that a comprehensive state groundwater management code was a prerequisite to federal authorization of the Central Arizona Project (a massive US Bu reau of Reclamation project to bring Colorado River water to central Arizona irrigation districts and municipalities). In 1980, the legislature adopted the Groundwater Management Act (Arizona Administrative Code 1990b), which identified area s requiring implementation of specific water conservation programs to ba lance groundwater withdrawal and demand by 2025. A number of other legislative initiatives have resulted in str ingent conservation, particula rly of groundwater resources. Critical in achieving the state’s water conservation goals is the reclamation of municipal wastewater. In response to mandated municipality-specific, per capita water-use targets based on a phased conservation program, some Ar izona cities have develope d dual water distribution systems. Filtered and disinfected reclaimed water is purchased in some areas at rates equal to that for potable water. Some cities require the use of reclaimed water on all new golf courses and parks a nd are considering mandatory retrofit for these irrigation uses. The Arizona Department of Water Resources has provided further incentives for

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

8

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

water reclamation by not including reclaimed water i n calculating the average per capita municipal demand. Recent legislation authorizing underground storage and recovery provides a mechan ism for subsur face storage to accommodate seasona l demands for irrigation water typical of the arid Southwest (Arizona Administrative Code 1990 a,c). Legal disputes over the identity and ownership of reclaimed water and water-quality considerations for uses other than la ndscape irrigation remain to be resolved.

North Carolina North Carolina, like Florida, has a reasonable amount of yearl y rainfal l amounting to more than 40 in. on average across the state. Over the past decade, the state has experienced significant extremes in weather ranging from serious hurricanes that have reached inland as far as the middle ofissues the state (Charlotte) to three exceptional droughts. Further bating water resource in the state is that the major metropolitan areas of theexacerstate, with the exception of Charlotte, are all located at the top of three major river drainage basins. (These rivers feed the second and third largest estuaries in the United States.) For the most part, a ll avail able water resourc e sites are ful ly developed and inter-basin trans fer is not permitted, so reclaimed water becomes a more serious planning consideration for all communities. To address this issue, before any community can get a permit to upgrade either a water plant or a wastewater plant or build a new facility, a study must be done to assess the feasibility of deve loping reclaimed water . This is an i mportant admin istrative step that ensures that water reuse will be taken seriously as a water resource.

REFERENCES _______________________________________________ Arizona State Legislature. 1990a. Arizona Administrative Code, Title 36, Chapter 35, Section 21, Environmental Quality Act. Phoenix, Ariz. . 1990b. A rizona Administrative Code, Title 45, Chapter 2, Section 86, Groundwater Management Act. Phoenix, Ariz. . 1990c. Arizona Administrative Code, Title 45, Chapter 2.1, Section 14, Underground Water Storage Recovery. Phoenix, A riz. AWWA. 2001. The Drinking Water Dictionary . Denver, Colo.: American Water Works Association. California State Water Resources Control Board. 1985. The Porter– Cologne Water Quality Control Act. Sacramento, Calif. Florida State Legislature. 1988. Florida Administrative Code, Chapter 17– 40, Water Policy, Section 17–40.030. Tallahassee, Fla. Frontinus, S.J. 1973. The Water Supply of the City of Rome (trans. by Clemons Herschel). Boston, Mass.: NEWWA.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Okun, D.A. 1973. Planning for Water Reuse. Jour. AWWA, 65(10):617. Denver, Colo.: AWWA. . 1982. Dual Water System s. Zurich, Switzerland: International Water Supply Association. Sedgw ick, T.W. and H.P. Letton. 1911. Has the Time Come for Double Municipal Water Supplies, One—Naturally Pure—for Drinking a nd Cooking, the Other—Denatured and Sterilized— For All Other Purposes? Jour. NEW WA, 25:400. Boston, Mass. Southwest Florida Water Management District. 1985. Consumptive Use of Water, Chapter 2 (11). Tampa, Fla. United Nations Economic and Social Council. 1958. Water for Industrial Use Report E3058 ST/ECA/50. Geneva, Switzerland. United States Public Health Serv ice. 1962. Drinking Water Standards. Federal Register, Mar. 6, 1962. pp. 2152–55.

Washington D.C.

AWWA MANUAL

Chapter

M24

2 Water Reuse Regulations and Guidelines Reclaimed water has been successfully used for a wide range of nonpotable applications in the United States. While the use of reclaimed water for nonpotable purposes has been demonstrated to be safe in the United States, adverse health consequences associated with the reuse of raw or improperly treated wastewater in other countries are well documented. As a result, due di ligence has resulted in water reuse sta ndards and guidelines for nonpotable reuse that are directed principally at public health protection and are based on the control of pathogenic organisms. Water-quality requirements not associated with public hea lth or environ mental protection are seldom included in water reuse criteria by regulatory agencies. However, during development of water reuse regulations and guidelines, regulatory agencies also consider factors such as economics, technical feasibility, enforcement, and political realities. While the USEPA has published guidelines for water reuse (USEPA 2004), there are no federal regulations governing water reclamation and reuse in the United States, and water reuse criteria are developed at the state level. Reclaimed-water standards vary considerably among states, although those with extensive reuse experience generally have comparable, conservatively based criteria or guidelines. Arguments for less restrictive standards are often predicated on a lack of documented health hazards rather than on any certainty that hazards are small or nonexistent. In the absence of a common interpretation of scientific data, selection of treatment processes and water quality limits wil l continue to be somewhat subjective and inconsistent among the states. Making reclai med water suitable and safe for reuse applicatio ns is achieved by eliminating or reducing the concentrations of microbial and chemical constituents of concern through wastewater treatment and/or by limiting public or worker exposure to the water via design and operational controls. Fa ctors that af fect the qua lity of reclaimed water include source water quality, wastewater treatment processes and treatment effectiveness, treatment reliability , storage, and distr ibution system design and operation similar to the multiple barrier concepts of the Safe Drinking Water Act. The design of distribution systems (pipeline materials, separation, etc.) is discussed in Chapter 5. Most states require

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

9

Not for Resale

10

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

implementation of industrial source control programs (e.g., pretreatment programs) to limit the input of chemical constituents that may adversely affect biological treatment processes a nd subsequent acceptabilit y of the water for specific uses.

EXISTING STATE REGULATIONS ______________________________ In the past, most state water reuse criteria were developed in response to a need to regulate a growing number of water reuse projects in the particular state. In recent years, some states that currently have few reuse projects have taken a proactive approach and have adopted water reuse criteria or guidelines, which tend to encourage implementation of projects. Some states (e.g., Arizona, Cali fornia, Florida, and Texas) that have had cr iteria for a number of years have revised their water reuse regulations in recent years to address additional reclaimed-water uses, advances in wastewater treatment technology, and increased knowledge in the areas of microbiology and public health protection. These states (and others) have developed regulations for many types of nonpotable reclaimed-water applications.

Types of Nonpotable Reuse No states have regulations that cover all potential uses of reclaimed water, but several states have extensive regulations that include criteria for a wide range of end uses of reclaimed water. Some states have regulations or guidelines directed at land treatment of wastewater effluent or land application of wastewater, emphasizing additional treatment or effluent disposal rather than intentional beneficial reuse, even though the effluent may be used for irrigation of agricultural sites, golf courses, or public access lands. The absence of state criteria for specific reuse applications does not necessarily prohibit those applications; many states evaluate specific uses on a ca se-by-case basis. General categories of nonpotable-water reuse applications are presented in Table 2-1.

Table 2-1

Uses of reclaimed water CategoryofUse

SpecificTypesofUse

Landscape irrigation

Parks, playgrounds, cemeteries, golf courses, roadway rights-ofway, school grounds, greenbelts, residential, and other lawns

Agricultural irrigation

Food crops, fodder crops, fiber crops, seed crops, nurseries, sod farms, silviculture, frost protection

Nonpotable urban uses (other than irrigation)

Toilet and urinal flushing, fire protection, air conditioner chiller water, vehicle washing, street cleaning, decorative fountains, and other water features

Impoundments

Ornamental,recreational

Environmentaluses

Streamaugmentation,marshes,wetlands,fisheries

Groundwater recharge

Aquifer storage and recovery, saltwater intrusion control, ground subsidence control

Potable-water supply augmentation (indirect potable reuse)

Groundwater recharge, surface water augmentation

Industrialuses

Cooling,boilerfeed,stackscrubbing,processwater

Miscellaneous

Aquaculture,snowmaking,soilcompaction,dust control,equipment washdown, livestock watering

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

WATER REUSE REGULATIONS AND GUIDELINE S

Table 2-2

Summary of state reuse regulations and guidelines for nonpotable reuse applications

State Alabama Alaska Arizona l Arkansas California l Colorado l l Connecticut Delaware l Florida l Georgia Hawaii Idaho l Illinois l Indiana l Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada l New Hampshire New Jersey New Mexico New York North Carolina l l North Dakota Ohio Oklahoma l Oregon l Pennsylvania Rhode Island South Carolina l South Dakota Tennessee l Texas l Utah l Vermont Virginia l Washington West Virginia Wisconsin Wyoming l Source:

11

s n o ti a l u g e R

s n o ti a l u g e R o N

s e in l e d i u G

s e n li e id u G r o

d e t c i r t s e r n

e l b a t o p n o U N

s e s U n a b r U

n o N d te ic tr s e R

l

n a b r U e l b s a t e o s p U

l a r u tl u ic r g A

s p o r C d o o F

l

l a r u tl u ic r g A

f o n io t a g i r r I

s p o r C d o o f n o N

l a n o ti a e r c e U R d e t c i r t s e r n

s t n e m d n u o p Im

d te ic tr s e R

l a n o ti a e r c e R

s t n e m d n u o p Im

l ta n e m n o ir s v e n s E U

s e s U l a i r t s u d n I

l

l

l l l l l l

l

l

l

l

l

l

l

l

l

l

l

l

l

l l ll

l

l l l l l

ll

l l

l

l

l

l

l

l

l

l

l

l

l

l

l

ll

l

l

l l

l l

l

l

l

l

l

l

l

l

l l l l l

l l

l

l

l

l

l l l

l l

l

l

l

l

l

l

l l

l

l

l

l

l

l

l

l l

llll l

l

l

l

l

l

l

l

l

l

l

l l

l

l

l l

l lll

l

l

l

l

l

l

l

l

l l ll

ll

l

ll

l

ll

l l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l ll

ll

l

l

l

l l

l

l

l

l

l

l

l

l l l

l

l

l

l

Updated from US Environmental Protection Agency (2004).

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

f o n io t a g i r r I

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

12

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Status of State Regulations and Guidelines Table 2-2, adapted from the USEPA Guidelines for Water Reuse (USEPA 2004), summarizes the extent of current water reuse regulations and guidelines for nonpotable applications by state for different types of reuse. The table identifies those states that have regulations or guidelines and those that currently do not have either. Based on the data in Table 2-2, 25 states have adopted regulations regarding the use of reclaimed water, 16 states have guidelines or design standards, and nine states have no regulations or guidelines. These data are somewhat misleading, as they include regulations and guidelines from some states that are directed at land disposal of effluent or land application of wastewater intended primarily as a disposal mechan ism rather than beneficial reuse. Whereas regulations are legally adopted, enforceable, and mandatory, guidelines generally are advisory, voluntary, and nonenforceable. In some cases, guidelines are incorporated in water reuse permits and, thus, become enforceable requ irements. Some states prefer the use of guidelines to provide flexibility in regulatory requirements depending on project-specific con ditions, which can result in di ffering requirements for similar uses within a state a nd lead to inequities in water reuse permits if guidelines are not uniformly imposed. As reclaimed water use becomes more pronounced in states having guidelines, most states eventually progress to development and imposition of regulations. Specific applications within each type of reuse listed in Table 2-3 are identified below: •

•

•

Unrestricted nonpotable urban uses—irrigation of parks, playgrounds, school yards, athletic fields, and residential property; toilet and urinal flushing, air conditioning, fire protection, construction, ornamental fountains, and reflecting pools; Restricted nonpotable urban uses—golf courses, cemeteries, highway medians, and similar areas; Agricultural irrigation of food crops—irrigation of food crops intended for human consumption. This category is often further classified as to whether the foodbetween crop is tothe be reclaimed processed water or consumed rawportion and whether contact and edible of the there crop. is direct

•

•

•

•

•

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Agricultural irrigation of nonfood crops—irrigation of fodder, fiber and seed crops, pastureland, commercial nurseries, and sod farms; Unrestricted recreational impoundment—an impoundment of water for which no limitations are imposed on body contact water recreation activities; Restricted recreational impoundment—an impoundment of reclaimed water for which recreation is limited to fishing, boating, and other noncontact recreational activities where only incidental contact with reclaimed water occurs; Environmental uses—creation of artificial wetlands, enhancement of natural wetlands, and sustainment of stream flows; and Industrial uses—cooling-system makeup, boiler feed water, process water, and general washdown.

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

WATER REUSE REGULATIONS AND GUIDELINES

13

Table 2-3 Number of states with regulations or guidelines for each type of nonpotablewater reuse Number of States

Type of Reuse

28

Unrestricted nonpotable urban

28

Irrigation Toilet flushing

10

Fire protection

9 9

Construction

11

Landscape impoundment

6

Street cleaning Restricted nonpotable urban Agricultural (food crops)

34 21

Agricultural (nonfood crops)

40

Unrestricted recreational

7

Restricted recreational

9

Environmental (wetlands)

3

Industrial

9

Source:

Adapted from US Environmental Protection Agency (2004).

TREATMENT, QUALITY, AND MONITORING EQUIPMENT _________ Treatment and Quality Requirements ` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Regulations or gu idelines commonly include requirements addressing water quality, monitoring, treatment processes, treatment reliability, operation and maintenance, use area controls, cross-connection control, and permitting. Most state water reuse regulations specify both reclaimed-water quality lim its and treatment process requiremen ts, although a few states, such as Texas and New Mexico, do not prescribe treatment processes and rely solely on water-quality li mits. The most common parameters for which wate r-quality li mits are imposed are biochemical oxygen demand (BOD), turbidity or total suspended solids (TSS), total or fecal coliform bacteria , and chlori ne contact time and residual. Currently, no state reclaimed-water microbiological quality criteria are based on rigorous risk assessment determinations. Most state regulations include two or more “classes” of reclaimed-water requirements, which become increasingly more restrictive as the potential for direct or indi rect human contact with reclaimed water increases. Low-quality reclaimed water ( e.g., secondary treatment with no or mini mal d isinfection) is acceptable in some states for uses where there is no human contact with the water, such as irrigation of pasture for nonmilki ng animals or i rrigation of seed crops not intended fo r human consumption. In ma ny states, the definition of secondary treatment requires that neither the BOD nor TSS exc eed 30 mg/ L. Daily sampling for BOD and TSS, using composite samples is usually required, although less frequent sampling is allowed in some states. A few states use the term oxidized wastewater to define secondary treated wastewater, where oxidized wastewater is defined as wastewater in which the organic matter has been stabilized, is nonputrescible, and contains d issolved oxygen. Most state regulations do not require a specific ty pe of secondary treatment (e.g., conventional activated sludge, extended aeration activated sludge, lagoon systems, and other types of secondary treatment) for wastewater to be acceptable. For uses such as restricted access irrigation sites where contact with reclaimed

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

14 PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

water is unlikely but may occur incidentally, a higher level of treatment (e.g., secondary treatment with a moderate level of disinfection that is not sufficient to destroy all pathogens) is ty pically required, although some states requi re relatively high levels of disinfection for uses of this type. The most str ingent treatmen t and quality requirements apply to reclaimed water used for the irrigation of food crops eaten raw, unrestricted access landscape irrigation, and other nonpotable urban reuse applications such as toilet and u rinal flushing, fire protection, vehicle washing, and simila r uses where either direct or indirect contact with the water is expected. For these uses, most states take a conservative approach and requi re secondary treatment, filtration (chemical coagu lation may be required prior to filtration), and a high level of disi nfection (e.g., 2.2 total coli/100 mL or no detectable fecal coli/100 mL) to eliminate pathogenic organisms or reduce them to insigni ficant levels in the reclaimed water. In most states that have definitive water reuse criteria, alternative treatment methods may be acceptable if they can be demonstrated to be as effective and reliable as those prescribed in t he regulations (Crook 1998). For exa mple, although most state regulations are based on using chlorine for disinfection, UV radiation that reliably achieves the required level of disinfection generally is acceptable. Similarly, membrane treatment such as microfiltration is an effective alternative to conventional media filtration. Table 2-4 illustrates the variation in treatment and quality requirements in selected state regulations for several nonpotable applications of reclaimed water. Similar variations among criteria occur for other uses of reclaimed water. A more detailed summary of all state water reuse regulations or guidelines as of 2004 is included in the USEPA Guidelines for Water Reuse .

Monitoring Requirements Decisions involving monitoring i nclude selection of water-quality parameters, numerical limits, sa mpling frequency , and the monitoring compliance point. Chemical constituents. With a few excep tions, there appear to be mi nimal health risks a ssociated with chemical constituents wher e reclaimed water is used for nonpotable applications; therefore, reclaimed water requirements typically focus on microbial health risks. While ma ny industrial uses require water of higher quality than that ty pically present in reclaimed water, water reuse regulations are intended to provide health protection and only include requirements to attain that end. Some industrial uses of reclaimed water, such as incorporating reclaimed water into food or drin k products, are prohibited. Effects of physical parameters (e.g., pH, color, temperature, and particulate matter) and chemical constituents (e.g., chlorides, sodium, and heavy metals) are well known, and recommended limits have been established for many constituents (National Academy of Sciences–National Academy of Engineering 1973; USEPA 1981; Water Pollution Control Federation 1989; Westcot and Ayers 1985). While there has been some concern regarding irrigation of food crops with reclaimed water, available data indicate that potentially toxic organic constituents do not enter edible portions of plants (National Research Council 1996), and reuse regulations do not include limits for pesticides or other trace organic contaminants. Organic matter. Some of the adverse effects associated with organic substances are that t hey are aesthetically d ispleasing (may be malodorous, impart color , and create unsightly deposits), provide food for microorganisms, adversely affect disinfection processes, and consume oxygen. BOD limits are intended to demonstrate that the organic matter has been stabili zed via t reatment, is nonputr escible, and has been lowered to levels commensurate with anticipated types of reuse. The compliance point fo r BOD typically is after secondary treatment or after the final treatment proc ess (i.e., in the product water as it leaves the treatment facility).

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

WATER REUSE REGULATIONS AND GUIDELINES

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

17

Particulate matter. The removal of suspended matter is related to health protection. It is known that particulate matter can shield microbes from disinfectants. Organic matter consumes chlorine, resulting in less of the disin fectant being available for destruction or inactivation of microbial pathogens. Although reclaimed-water monitoring requirements for particulate matter vary from state to state, there is general agreement that, where a high level of disin fection is requi red, particulate m atter should be reduced to low levels, e.g., 2 nephelometric turbidity units (NTU) or 5 mg/L TSS, prior to disinfection to ensure reliable destruction or i nactivation of microbial pathogens. Suspended solids ’ measurements are typically performed daily on a 24-hour composite sample and produce an average value for the sampling period. Monitoring for total suspended solids is appropriate for reclaimed water that receives only secondary treatment, because the effluent is not intended to be completely free of measurable levels of all pathogens. However, for high level nonpotable uses of reclaimed water where contact, ingestion, or inhalation is likely, continuously monitored turbidity is superior to daily suspended solids measurements as an aid to treatment performance. Where turbidity monitoring is required, most states requi re that turbidity be continuously monitored. California specifies different turbidity requirements depen ding on type of treatment. Where media filtration is the added treatment process, turbidity after filtration cannot exceed an average of 2 NTU within a ny 24-hour period, cannot exceed 5 NTU more tha n 5 percent of the time within a 24-hour period, and cannot exceed 10 NTU at any time. Where membranes are used in lieu of media fi ltration, turbidity cannot exceed 0.2 NTU more than 5 percent of the time withi n a 24-hour period and ca nnot exceed 0.5 NTU at any ti me. This turbidity requirement is based on observed turbidity levels in product water from properly designed and operated microfiltration unit processes having a nominal pore size in the 0.1-mm range and reflects attainability and good engineering practice (Crook 2002). Low turbidity or suspended solids values by themselves do not indicate that reclaimed water is devoid of microorganisms. As such, turbidity or total suspended solids measurements are not used as a n indicator of microbiolo gical qual ity but rather as a quality criterion for wastewater prior to disinfection. It is impractical to monitor reclaimed water for Microbial indicator organisms. all pathogenic organisms of concern, and surrogate parameters are un iversally accepted. In the United States, either total or fecal coliform organisms are the preferred indicator organisms for reclaimed water. Other indicator organisms (e.g., enterococci, E. coli, Clostridium perfringen , and coliphages ) have been proposed but have not gained wide acceptance. Coliform samples are usual ly required to be collected on a da ily basis duri ng peak flow conditions to represent the most demand ing treatment facil ity operati ng conditions. Regulatory compliance varies in different states but usually is based on median or geometric mean values over a given time period. Wh ile high levels of coliforms are i ndicative of fecal contamination, the absence of coliform organisms — by itself — is not an adequate indicator that the water is uncontaminated. The total coliform ana lysis includes enume ration of organisms of both fecal and nonfecal srcin, while the fecal coliform analysis is specific for coliform organisms of fecal srcin. Therefore, fecal coliforms are better indicators of fecal contamination than total coliforms. Regulatory decisions regarding the selection of which colifo rm group to use are somewhat subjective. There is no consensus among microbiologists that the total coliform analysis is superior to the fecal coliform analysis. The use of total coliforms provides an added safety factor that appeals to regulatory agencies that adhere to a conservative ap-

proach to water reuse. Water reuse regulations do not include specific lim its for parasitic or vira l pathogens. Parasites have not been shown to present a health problem at water reuse operations in the United States, although there has been considerable interest in recent years regarding the occurrence and significance of Giardia and Cryptosporidium in reclaimed water.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

18

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

Monitoring for such organisms is required in some states. For example, Florida requires monitoring of Giardia and Cryptosporidium with sampling frequency based on treatment plant capacity (Florida Department of Environmental Protection 1999). In consideration of the likelihood of ingesting reclaimed water while swimming in nonrestricted recreational impoundments and the paucity of information regarding parasite removal where a discrete chemical clarification process is omitted from the treatment train, the California regulations require that reclaimed water used for nonrestricted recreational impoundments be monitored for ente ric vi ruses, Giardia , and Cryptosporidium during the first two years of operation if the treatment chain does not includ e a chemical clari fication unit process between the coagulation and filtration processes (State of California 2000a). Viruses are of concern in reclaimed water, but virus limit s are not included in regulations for a number o f reasons, including the fact that vi ruses can be reduced or inactivated to low or immeasurable levels via appropriate wastewater treatment that includes secondary treatment, chemical coagulation, filtration, and a high level of disinfection (Sanitation Districts of Los Angeles County 1977; Engineering-Science 1987; Crook 1989; and Yanko 1993). As ana lytica l detection and identification techniques have improved, it ha s become apparent that coliforms, by themselves, are inadequate indicators of the presence or concentration of so me pathogens, particularly viru ses and parasites, as many pathogens have been shown to be more resistant to wastewater treatment than classical microbial indicators such as coliforms. In addition, concerns for pathogenic organisms such as Giardia and Cryptosporidium , which may srcinate from nonhuman sources, have led to questioning the use of indicators that ar ise primar ily from human fecal inputs. Therefor e, it is improper to infer that a high level of either total or fecal coliform removal — by itself — is indicative of high levels of pathogen removal from reclaimed water. Disinfection. Where chlorine is used as the disi nfectant, many states require continuous monitoring of chlorine residual and specify both the chlorine residual and contact time that must be met, particularly for reclaimed water uses where contact with the water is likely to occur. Required theoretical disinfection contact times differ substantially from state to state and range from 15 minutes to 2 hours at peak flow. While the need to maintain a chlorine residual in reclaimed-water distribution systems to prevent odo rs, slimes, and bacteria l regrowth was recognized early i n the development of dual water systems (Okun 1979), only since the late 1990s have regulator y agencies begun to require such residuals. Several states now require maintenance of a chlorine residual in d istribution systems carry ing reclaimed water. The USEP A Guidelines for Water Reuse recommend that a chlorine residual of at least 0.5 mg/L be ma intained in reclai medwater distribution lines. The use of ultraviolet (UV) irradiation for disinfection is becoming more prevalent at water reclamation facilities. Because UV does not leave a residual in water, it is advantageous to a dd a low dose of ch lorine to the reclaimed water as it enters the distribution system. Where UV is used for disinfection, many states do not specify UV dosage or design or operating conditions, although some state regulations require compliance with the Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse (NWRI 2003). These comprehensive guidelines address UV dose, reactor design, reliability, monitoring and alarm s, field commissioning testing, performance monitoring, and elem ents of an engineering report. The guidelines recommend, for example, a design UV dose of 100 mJ/cm 2 to reliably achieve a total coliform level of ≤2.2 total coli /100 mL a nd 5-log inactivation of seeded poliovirus in tertiar y treated reclaimed water . Monitoring compliance point. Because particulate matter has a direct influence on disinfection effectiveness, turbidity and total suspended solids limits usually are required to be met in the wastewater immediately after filtration. The location of

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

WATER REUSE REGULATIONS AND GUIDELINE S

19

the monitoring point for indicator organism regulatory compliance has been an issue in some states. One viewpoint is that the reclaimed water should meet all water-quality requirements at the point of use. Arguments in favor of this position generally center on the possible regrowth of microorganisms between the treatment plant and the point of reuse. However, restrictive coliform requirements, in conjunction with water quality and treatment process requirements, ensure that pathogenic bacteria are destroyed during disinfection and any bacterial regrowth would only be that of nonpathogenic coliform organisms. Viruses require living cells to invade and replicate themselves and do not increase in concentration in the open environment. Similarly, parasitic cysts and oocysts do not replicate in water. Many regulatory agencies subscribe to the rationale that any degradation that may occur during storage and distribution would be no different than that which would occur with the use of other water. This is not meant to imply that subsequent water quality control should be ignored. In most states, the monitoring compliance point for indicator or ganisms is immediately after disi nfection. Groundwater monitoring programs associated with irrigation of reclaimed water are required in several states. In general, groundwater monitoring programs require that at least one well be located hydraulically upgradient of the irrigation site to assess background groundwater quality within the aquifer and one or more wells be located hydraulically downgradient of the reuse site to monitor comp liance. Sampling para meters, limits, and frequency of sampling vary a mong states that require such monitoring.

Treatment Reliability Some states have adopted regulations or guidelines to ensure that reclai med water meets appropriate standards as it enters the distribution system. Reliability measures include alarm systems that warn of power failure or failure of essential unit processes, automati c standby power supplies, multiple or standby treatment process units, emergency storage or disposal of inadequately treated wastewater , elim ination of treatment process bypassing, monitoring devices and automatic controllers, and flexibility of design. Some states require adherence to USEPA’s Class I reliabilit y requirements (USEPA 1974), which include many of the measures previously stated. Several states require filtration of reclaimed water when human contact with the water is likely. Water reuse regulations in some of these states require that chemical addition facilities be instal led prior to the filtration unit process, although the chemical addition facilities may remain idle u nless turbidity or total suspended solids lim its cannot be met after filtration.

Use Area Controls There is little consistency on use area controls specified in state regulations. Commonly specified use a rea controls include the following: color -coding reclaimed water pipelines and appurtenances; cross-connection control provisions; signage; setback distances between reclaimed-water use areas and various sites such as potable-water supply wells, property lines, residential areas, and roadways; confinement of reclaimed water to the designated use area; protection of drinki ng water fountains against reclai med water spray; and prohibition of hose bibbs on reclaimed-water irrigation systems. Detailed discussion of some of these use area controls is in Chapter 4. Setback distances. The intent of setback distances, which a re sometimes called buffer zones, iscontamination to prevent excessive human contact the reclaimed or tomodprevent potential of potable-water supplywith sources. Although water predictive els have been develop ed to esti mate microorganism concentrations in aerosols or larger water droplets resulting from spray irrigation of wastewater, setbac k distances a re somewhat arbitrarily determi ned by regulatory agencies based on experience and judgment.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

20

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Many states have established setback dista nces between reclaimed-water use areas and surface waters, potable-water supply wells, or areas accessible to the public. Setbacks are usually required where reclaimed water is used for spray irrigation, cooling water in towers, and other uses where spray or mist is formed. Setbacks may also be required at irr igation or impoundment sites to prevent perco lated reclaimed water from reaching potable-water supply wells or surface waters. Setback distances var y depending on the quality of reclaimed water, type of reuse, method of application, and purpose of the setback (e.g., to avoid human contact with the water or protect potable water sources from contamination). Setback distances, where required, vary considerably from state to state, and range from 15 m (50 ft) to as much as 240 m (800 f t). Some states do not require setback distances from irr igated areas to areas a ccessible to the public if a tertiar y treatment and a high level of disinfection is provided. Cross-connection control. States with comprehensive water reuse criteria typically include cross-connection control regulations to prevent interconnecting reclaimed and potable-water pipelines. Regulations often address identification of transmission and distribution lines and appurtenances via color-coding, taping, or other means; pipeline separation; allowable pressures; surveillance; and backflow-prevention devices (see Chapter 5). At use areas that receive both potable and reclaimed water, backflow-prevention devices are usually required on the potable-water supply line to each site to reduce the potential of contaminating the potable drinking water system in the event of a cross-connection at a use area. Direct connections between reclaimed-water and potable-wate r lines a re not allowed in any state. Some states allow the use of reclaimed water for toilet and urinal flush water in buildings where residents or other unauthorized personnel do not have access to the plumbing system for repairs or modifications. The use of reclai med water in single-fam ily residential buildi ngs is generally prohibited. Reclaimed water used inside buildings for toilet and urinal flushing or for fire protection presents special cross- connection contro l concerns. Although such uses do not result in frequent human contact with the water, regulatory agencies usually require that the reclaimed water be essentially pathogen free to reduce health hazards upon inadvertent cross-connection to potable-water systems. California’s Water Recycling Criteria (State of California 2000) require compliance with the Cal ifornia Department of Public Health (CD PH) cross-connection control regulations (State of California 2000b), which address the use of reclaimed water. They require that water systems serving residential property through a dual water system that uses reclaimed water for landscape irrigation must, as a minimum, be protected by a doublecheck-valve-assembly backflow preventer. The same requirement applies to a public water system in buildings using reclaimed water in a separate piping system within buildings for fire protection. A reduced pressure principle backflow-prevention device is required as a min imum to protect the potable system at sites other than those previously mentioned. An air gap separation is required where a public water system is used to supplement a reclaimed water supply. California’s criteria for dual plumbed systems within buildings include the following requirements: •

•

•

•

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Internal use of reclaimed water within any individually owned residential unit, including multiplexes or condominiums is prohibited; Submission of a report to CDPH that includes a detailed description of the intended use area, plans and specifications, and cross-connection control provisions and testing procedures; Testing for possible cross-connections at least once every four years; Notification of any incidence of backflow from the reclaimed-water system into the potable water system within 24 hours of discovery;

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

WATER REUSE REGULATIONS AND GUIDELINE S

•

•

21

Conformance to the CDPH cross-connection control regulations; and Facilities that produce or process food products or beverages can use reclaimed water internally only for fire suppression systems.

Storage Requirements Storage requirements vary from state to state a nd are dependent on geographic location, climate, and site conditions. A minimum storage volume equal to 3 days of the average design flow is typical in water-short states with warm climates, while more than 200 days of storage are required in some northern states because of the high number of nonirrigation days as a result of high rai nfall or freezing temperatures. Many of the states that have storage requirements in reuse their regulations require that aand water balance be performed on the water system, takiorngguidelines into account all inputs outputs of water to the system.

US Environmental Protection Agency Guidelines The USEPA, in conjunction with the US Agency for International Development, published Guidelines for Water Reuse (USEPA 1992) in 1992. The guidelines were updated in 2004 (USEPA 2004) to address technological advances, research data, and other information generated in the l ast decade. The primar y purpose of the document is to provide guidelines, with supporting information, for utilities and regulatory agencies in the United States, particula rly in st ates where st andard s do not exist or are being rev ised or ex panded. T he guidelines address various aspects of water reuse and include recommended treatment processes, reclaimed-water qual ity limits, monitoring frequencies, setback dista nces, and other controls for various water reuse applications. A summary of the guidelines for nonpotable reclaimed water applications is presented in Table 2-5. Both reclaimed-water qualit y limits and wastewater treatment unit processes are recommended for the following reasons: water quality criteria involving surrogate parameters alone do not adequately characterize reclaimed water quality; a combination of treatment and quality requirements known to produce reclaimed water of acceptable quality obviates the need to monitor the finished water for certain constituents; expensive, time-consuming, and in some cases, questionable monitoring for pathogenic microorganisms is eliminated without compromising health protection; and treatment reliability is enhanced. The guidelines recommend that, regardless of the ty pe of reclaimed-water use, some level of disinfection should be provided to avoid adverse health consequences from inadvertent contact or accidental or intentional misuse of a water reuse system. For nonpotable uses of reclaimed water, two different levels of disinfection are recommended. Reclaimed water used for applications where no direct public or worker contact with the water is expected should be disinfected to achieve a fecal coliform concentration not exceeding 200/100 mL for the following reasons: most bacterial pathogens wil l be destroyed or reduced to low or insignificant levels in the water; the concentration of viable viruses will be reduced some what; disinfection of secondary effluent to this coliform level is readily achievable at minimal cost; and sign ificant health-related ben efits associated with disinfection to lower, but not pathogen-free, levels are not obvious. For uses where direct or indirect contact with reclaimed water i s likely or expected, and for dual water systems where there is a potential for cross-connections with potablewater lines, the guidelines recommend a high level of disinfection to produce reclaimed water having no detectable fecal coliform organisms/100 mL. This more restrictive disinfection level is intended for use in conjunction with tertiary treatment and other water-quality limits, such as a turbidity of 2 NTU in the wastewater prior to disinfection. This combination of treatment and water-quality l imits ha s been shown to be capable of

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

22

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

producing reclaimed water that is essentia lly free of measurable levels of bacterial and viral pathogens. The guidelines i nclude lim its for fecal coliform organisms but do not include parasite or virus limits. Where filtration and a high level of disinfection are recommended to produce reclaimed water that is essentially free of measurable levels of pathogens, the guidelines state that it may be necessary to add chemicals prior to filtration to a ssure complete removal or inactivation of p arasites and vir uses. As with state water reuse criter ia, the recommendations in Table 2-5 are pr incipal ly directed at health protection and include various control measures. For example, for nonpotable urban uses of reclaimed water, the guidelines include the following recommendations: clear and odorless product water; a setback distance of 15 m (50 ft) from irrigated areas to potable-water supply wells; no measurable levels of pathogen organisms in the reclaimed water; maintenance of a chlorine residual of at least 0.5 mg/ L in the d istribution system; treatment reliability and emergency storage or disposal of inadequately treated water; and cross-connection control devices on potable-water service lines and colorcoded or taped reclaimed water lines and appurtenances. Similar design a nd operational recommendations are included in the guidelines for the other reclaimed-water nonpotable applications. It is explicitly stated in the Guidelines for Water Reuse that the recommended treatment unit processes and water-quality li mits presented in the gu idelines “are not intende d to be used as definitive water reclamation and reuse criteria. They are i ntended to provide reasonable guidance for water reuse opportunities, particularly in states that have not developed their own criteria or guidelines” (USEPA 2004).

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

WATER REUSE REGULATIONS AND GUIDELINES

tsi m li ) p o c(r la r u tl u icr ga ed d n e m m o c re tl u s n o C

ts en m m o C

2

r e t a w e ts a w l a p i c i n u m f o e s u re le b a t o p n o n r o f s e n il e d i u g d e st e g g u s A P E S U -5 2 e l b a T

s ce an t is D k c a b et S

o t ) m 15( tf 50

ert a g W - n ri d e ito m i n lca o M e R

ly k ee w – H p

ert a 1 -W yt d e lia m u ali Q c e R

t n e tm era T

es u ef R o es yp T

gn i es d e er h w se ti s n o tia gi rr i sse c c -a d el l o rt n co t A

sl. at e m r fo

re ta w el b at o p

9 – 6 = H p

ray d n ceo S

d e n s fla u e o R s e n p a ty b l r l U A

4

r u T

D O B L 7 g/ U mT 01 N 2

al ecf ,9 8 le L atb m 0 ect 0/1 e il d o o c N

– tyi d i b

n io t rat il F

n o ti ce f isn i D

-a ig rri e p ac s

fl o g.,g. (e n io t

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

l a ecf 14 ≤ ev ie h ca o t n io t ecf in is d d atn en m t ear t

.e ta ir p o r p ap e b ya m , L m 010 il/ co

n o tii d ad r)e ym l o p r o / d n a t n al u ago c( l a ic m e h C

t ee m to y asr s ce e n e b ay m n o ti ratl fi to r o ir p

s. n o tai d n e m m ceo r ityl a u q r tea w

rsau e m ian t n co t o n1 d l 1. u sn o e g sh o re h t at ap w d fs e o l m ia ev l le c re elb e a h T

s.s el r o d o d n a r ela c e b ld u o h s er at w d e im lac e R

t ca t n o c re g n o l a r o / d n a la u id se r e n rio l h c r e h gi h A

se s u irv ta h t er u s n e to ray s ecs e n eb ya m e m ti

. d ey ro t es d r o d tae vi t ca in er a esti s raa p d n a

e th n i re t ear g r o /L g m .05 f o la u sid re e in r o l h c A

ec u ed r o t d e d n e m m ceo r si m e syt so n it u ib r sti d

. h t w rgo er ali re tc a b d n a e,m lis ,s r o d o

st i m il ) p o r (c la r u lt ciu r ag d e d en m m o c re lt u s n o C

y.t il i b ai l re t n e m t ear t e d i v o r P

.s l at e m r fo

re ta w le ab t o p

to ) m 0 9( tf 00 3 y il a d – rm o ifl c C o

5 3

d e m ail erc tih w tc at n co ci l b u p f o ialt en t o p e th

ry a d n o esc .,g . e, t n e tm ae tr f o le evl r e w o l a, r et a w

s lle w yl p p u s

yl k ee w – D O B

6

ec u d re yl t an c fi i n igs esr u ase m la n io art e p o d an

s u o u in t n o

s, rk a, p ess r u o c

) iesr et e m ec

s u o u in t n o

– l a u id esr

l2 c C

10

/gL m 1 ≥

el c i eh v o las --

la u isd re l2 C

t el i g,to in sh a w

yl k ee w – D O B

ly k ee w – H p

6

9 – 6 = H p

n i e s ,u g n i h s u fl

n o i tcte o r p er fi

d an s m tse sy

ira l ciar e m m o c

s,r e n o tii d n o c

ess ru e h t o d n a

ac r ila m is h it w

re u s o p ex r o ss ec

r ate w e h t o t

Not for Resale

n o it a g i r r I a e r A s s e c c

5

D O B L g/ m 03

yr a d n co e S

n o ti ce f isn i D

vil A i d ,s e s t m c ra i tr f s d e o R S

s, ites re tu l cu

3

e b ay m L g/ m 30 an h t ss el S S ,T n o tia gi rr i y ra p s fI

s lle w yl p p u s

s. aed h r el k n ir sp f o g n i gg lo c d i o va t o ray ss ec e n

to ) m 0 3( tf 00 1

23

) 4 2 e g a p n o d e u itn n o c (

y.t il i b ai l re t n e m t ear t e d i v o r P le ib s ecs c a sa rea

fi ( icl b u p e th o t

– l a u id esr l2 C

s u o u in t n o c

lyi a d – S S T

y il a d – rm o ilf o C

S S T L g/ m 03

0 10/ li co 3 la 2,1 ,1 ecf 8 L 002 m

ase r rae h t o d an

icl b u p er e h w

b i h o r sp i ss cec a

) n io ta gi rr i y ra p s

10

la u id s e /L g 2r m lC 1 ≥

, d te trics er , d e it

t n e qu er f n i r o

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

WATER REUSE REGULATIONS AND GUIDELINE S

ict a qu a ct et o r p o t ry as s cee n e b ay

ts en m m o C

). d ’t n o c ( r e t a w e ts a w l a p ic i n u m f o e se u r e l b a t o p n o n r o f s e n il e d i u g d e ts e g g u s A P E S .U -5 2 e l b a T

.a n au f d n a a r o fl f o s iec e sp

m n o ti a in r lo h ce D 2

s ce an t is D k c a b et S

to ) m 510 ( tf 0 05

re t a g -W irn ed o ti mn ali o c M e R

yl k ee w

es u ef R o se p y T

r et a w e-l b ta o p

yl ek e w –

6

9 – 6 = H p

t o n m to t o b fi

– y it id

s u o u n ti n co

D O B L /g 7 U T mN 10 2

5 3

s t n e m d n u o p m I l a n io t a e r c e R

y ar d n co e S t ca t n lco ta en icd n I

4

n o tia r lit F

n o tic fe n is i D

d an g in h s fi ,. g e.(

ll fu d an )g n tia o b

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

s.e ey

lsl e w yl p p u s

– O D u rb H p B T

re ta 1 -W ty ed ail u im la Q ce R

t n e m aet r T

d n a in k s o t g n it tai rri n o n e b d l u o h s ater w ed m ia cel R

le b tac tee d o N

.s esl r o d o d n a ra le c e b d l u o h s ater w ed m ia cel R

aeg al d i vo a to yr as s cee n e b y a m l va o m er t en rit u N

.s t n e m d n u o p im in h t w rgo

r io r p n o tii d ad ) er ym l o p r o / d n a t n al gu a o (c la ic m e h C

al qu r et a w ete m o t ray ss cee n e b y a m n o ti rat l fi to

s. n o tia d n e m m o ce r y it

le ab r su ae m n ia t n o c t o n ld u o1 sh 1 .s re n ta eg w o t d h e ap m ia fo lc s er el v e le h T

cat t n o c re g n o l a r /o d n a l a u id esr eir n lo h c re h gi h A

d n a s es u r vi ta th re u s en o t yr as se c e n e b ya m e m ti

. d ye rto s e d r o ed t av it c a n ier a se ti s raa p

. d e m u s n o c e b n ac st en m d n u o p im in t h g u ac sh i F

o t y ars ecs e n e b y a m ess se c ro p l vao m er t en ir t u N

y. ilt i b ila er t en tm ear t e id v o r P

s u o u n ti n lr2 co C l–a u id se

lls e w yl p p u s

t o n m to t o b fi

y ila d – – S H p T

yl ai d – rm fo li o C

– la u id es

D O B L /g m 30

001 i/l o c 41, l 31 cae ,21 f L 0 m 20

ly k ee w

0 0 1l 0 a /i1 u l d o c 2 L esi la 8,1 / r ce L gm l 2 f m1 C ≥

6

S S T L /g m 30

5 3

y ar d s t n n o e c e m S t c tan o c y d o b

d e m lai ecr h it w

ed o w l al ert a w

d n u o p m I e p a c s d n a L

Not for Resale

m n o ti a n ri lo h ce D

a. n u af d n a a rfl o f o s ice e sp

r et a w -e l b ta o p

to ) m 0 15( tf 0 05

d lea es

yl ai d – rm fo li o C

s.t n e m d n u o p im n i h t w gro ea gl a id o va

ict a u q a tc te o r p o t ry as s ec e n e b ya

im ci t e h set A

e b ld u o h s re ta w d e iam cel r tih

y. ilt i b ila er t en tm ear t e id v o r P

tc w at n o c re k r o W

st en m d n u o p

– la u isd e rl 2 C

s u o u n it n co

yl ai d – D S O B T

yl ai d – rm o f li o C

D O B L /g m 30

001 i/l o c 4,1 l 31 cae 2,1 f L 00 m 2

ly eek w –

s u o u n ti n lr2 co C

6

l 2 10 l C a u /L g isd m re 1 ≥

S S T L /g m 30

5 3

h t i w cta t n co

e er h w ed d vi o r p e b d l u o h s , L m 0 /10il o c la ce f 41

.y el ik l

y. ilt i b ila er t en m t ear t e d iv o r P

) 6 2 e g a p n o d e u itn n o c (

d lea es

n o tic fe n is i D icl b u p er e h w

. d e iz m i in m

≤ vee i h ac to .,g .e , n io tc ef n sii d fl o ev el re h gi h A

is re ta w ed im lca er h ti w tc at n o c re rk o w t n e u eqr f

25

ert a w ed m i lac er

ed w o l al t o n is

s e s U n io t c u r t s n o C

y ar d n co e S

n o tic fe n is i D

, n io cta p m co il o S

,l tro n co ts u d

gag in h as w

g in k a, m et gae rg

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

0 1

l a u d i ers L /g l 2 mC 1

et e cr n co

26

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

-c a sa rea ch ae r t o n d l u o h s ary sp n

ts en m m o C

w lo b d in W

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

). d ’t n o c ( r e t a w e ts a w l a p ic i n u m f o e se u r e l b a t o p n o n r o f s e n il e d i u g d e ts e g g u s A P E S .U -5 2 e l b a T

2

s ce atn is D cak b et S

re ta g -W irn d e to i m n ail o ce M R

6

9 – 6 = H p

t en m t ae r T

es eu R f o se p y T

ly k ee w – D O B

ly k ee w – H p

re at 1 W - yt d e ila mu ail Q ec R

5 3

e s u e R l ia r t s u d n I

yr a d n o ce S

gu h o r th ec n O

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

c.i l b u p e h t r o s er rk o w o t le ssib e c el b ssi e cac sa er a

to ) m 90( tf 00 3

-c a sa rea ch ae r t o n d l u o h s y ra p s n

D O B L /g m 30

n o tic ef n i is D

g n li o o c

lb w o d in W

ly ek e w – S S T

S S T L /g m 30

el b ssi ec ac sa er a

to ) m 90( tf 030

icl b u p e h t o t

lyi a d – m r fo li o C

– l a u d sie r l2 C

3 ,1 21 8,

al ce f 0 20

L m 00 1/ li co

s u o u in t n o c

l2 C L g/ m 1

10

la u isd er

ly eek w – H p

ly k ee w – D O B

n o s d en ep ;d el b a rai V

o it ra n o it al u rci ce r

5 3

c.i l b u p e h t r o res k r o w to el ib s es c

yr a d n o ce S

gt in al u cr cei R

n o tic ef n i is D

g n li o o c

tsi im l tyi al u q r tea w d e d n e m m o ce ltru s n o C

r. et a w p u e k am r o f

. icl b u p e h t o t

d ec u d er e b ya M

ly ek e w – S S T

lyi a d – m r fo li o C

yl l a u s u is re s u y b t n e m aet rt la n o tii d d A f o le v le h ig h fi

– l a u d sie r l2 C

, n o is o rr c,o g n lai cs t n e ve r p to d e id v ro p

.g in m a o f d n a, g iln u o f, s th w rgo la ic go l o i b

si n o tic ef n i is d

d e d vi ro p

y.t il i ab il re t n e tm a er ted iv o r P

6

D O B L /g m 30

S S T L /g m 30

s u o u in t n o c

la 4 n o i gu a at o c rlt l fi cai d n ma e n h o (c it

) d e d ee n e b ya m

s er w o t

al ce f 0 20

.a n u fa d n a ar o fl f o se ic e p s icta qu a

ly k ee w – D O B

3 1, 21 ,8

e b ay d m l u st o n t. h e n s me ert rei m ta a u w q re d n re lt u yt a il n rgo a io u it n q d o re d st a t ce . a e ff d w at e et g ti leb u al in vi se ssi va ce ce e e n o P R

r et a w d e m ia l c re e th f o re tu a er p m te e h T

. m e sty s o ce tc e ffa yl es re v d a t o n ld u o h s

ta th er u s en to d e n igs e d e b d l u o h yst i ilc a F

y.t il i ab il re t n e tm a er ted iv o r P

r et a w le b at o p s e cah er re t a w d e im al ecr o n

s.r fei u aq ylp p u s

t n e m t ear t yr a d n o ce s, ts c je ro p g in d reap s r o F

.g in gg o lc t n ev re p o t ed ed e n eb ya m

-c fe in is d d n a n o it rta l fi , tsc je o r p n o ti jec in r o F

c fi ic e sp eti S

0 1

9 – 6 = H p

tc te ro p to ray ss e ce n e b ya m n o it a n rio l h ce D

L m 00 1/ li co

l a u id se r l2 C L /g m 1 ≥

y ial d – S S T

o t t o n t u ,b el b a ria V

6

: d ee c x e

3

e s u e R l a t n e m n o ir v n E

Not for Resale

lyi a d – m r fo li o C

el b ai ra V

,s d n al te W

d n a yr a d n o ce S

,s e h rsa m

D O B L /g m 30

– l a u d sie r l2 C

S S T L /g m 30

t-a e tr n o s d n e p e D

s u o u in t n o c

3 1, 21 ,8

al ce f 0 20

L m 00 1/ li co

). n i (m 5 n o tic ef n i is d

fei l d il w

t, at i ab h

m era st

es u d n a c fi ic e p -s tei S

n io ta n e m g au

e g r a h c e R r te a w d n u o r G

se u d n a c fi cie p set i S

g in d ae r p s y B

se u d an t en m

t en d n e p e d

t n e d en ep d

n io cte j n i r o

r fo ). n i (m yr a m ir P

r fo .) in m g 3( n i yr d a era d n o sp ce S

sr ife u aq o t in

r fo d es u t o n

re at w ci l b u p

n io ct je in

ly p p su

.g n ig g lco t n vee r p o t d e d ee n e b ya m n o ti

y.t lii b a lie r t n e tm a er ted iv o r P

28

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

REFERENCES _______________________________________________ Crook, J. 1989. Viruses in Reclaimed Water. In: Proceedings of the 63rd Annual Technical Conference, pp. 231-237, sponsored by Florida Section American Water Works Association, Florida Pollution Control Association, and Florida Water & Pollution Control Operators Association, November 12–15, St. Petersburg Beach, Fla. Crook, J. 1998. Water Reclamation and Reuse Criteria. In: Wastewater Reclamation and Reuse, pp. 627-703, T. Asano (ed.), Technomic Publishing Co., Ltd. Lancaster, Pa. Crook, J. 2002. The Ongoing Evolution of Water Reuse Criteria. In: Proceedings of the AWWA/WEF 2002 Water Sources Conference (CD-ROM). Las

Vegas, Nev. Engineering-Science.

1987. Monterey Wastewater Reclamation Study for Agriculture: Final Report. Prepared

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

for Monterey Regional Water Pollution Control Agency by EngineeringScience. Berkeley, Calif. Florida Department of Environmental Protection. 1999. Reuse of Reclaimed Water and Land Application. Chapter 62-610, Florida Administrative Code. Florida Department of Environmental Protection. Tallahassee, Fla. National Academy of Sciences-National Academy of Engineering. 1973. Water Quality Criter ia 1972. EPA/ R3/73/033. Prepared by the Committee on Water Quality Criteria, National Academy of SciencesNational Academy of Engineering, for USEPA. Washington, D.C. National Research Council. 1996. Use of Reclaimed Water and Sludge in Food Crop Irrigation. Washington,

D.C.: National Academy Press.

Okun, D.A. 1979. Criteria for Reuse of Wastewater for Nonpotable Urban Water Supply Systems in California. Report prepared for the Califor-

nia Department of Health Services, Sanitary Engineering Section. Berkeley, Calif. Sanitation Districts of Los A ngeles County. 1977. Pomona Virus Study: Final Report. California State Water Resources Control Board. Sacra mento, Calif. State of California. 2000a. Water Recycling Criteria. Title 22, Division 4, Chapter 3, California Code of Regulations. California Department of Health Services, Drinking Water Program. Sacramento, Calif. State of California. 2000b. Cross Connection Control Regulation s. Title 17, Division 1, Chapter 5, California Code of Regulations. California Depart ment of Health Serv ices, Drin king Water Program. Sacramento, Calif. US Environmental Protection Agency. 1974. Design Cr iteria for Mechanical, Electric, and Fluid System and Component Reliability . MCD05. EPA-430-99-74-001. Washington,

D.C.: USEPA, Office of Water Program Operations. US Environmental Protection Agency. 1981. Process Design Manual: Land Treatment of Municipal Wastewater . EPA/625/1-81-013. Cincinnati, Ohio: USEPA, Center for Environmental Research Information. US Environmental Protection Agency. 1992. Guidelines for Water Reuse. EPA/625/R-92/004, Cincinnati, Ohio: USEPA, Office of Research and Development, Center for Environmental Research In formation. US Environmental Protection Agency. 2004. Guidelines for Water Reuse. EPA/625/R-04/108, Cincinnati, Ohio: USEPA, Office of Research and Development, National Risk Management Research Laboratory.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

WATER REUSE REGULATIONS AND GUIDELINE S

Water Pollution Control Federation. 1989. Water Reuse (Second Edition): Manual of Practice SM-3. Alexandria, Va.:

Water Pollution Control Federation. Westcot, D.W. and R .S. Ayers. 1985. Irr igation Water Quality. In: Irrigation with Reclaimed Municipal Wastewater–A Guidance Manual. G.S. Pettygrove

and T. Asano (eds.), pp. 3-1–3-37. Prepared by the Cali fornia State Water Resources Control Board. Chelsea, Mich.: Lewis Publishers Inc.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

29

Yanko, W.A. 1993. Analysis of 10 Years of Virus Monitoring Data from Los Angeles County Treatment Plants Meeting California Wastewater Reclamation Criteria. Water Environ. Research., 65(3):221–226. Alexandria, Va.

This page intentionally blank.

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

AWWA MANUAL

Chapter

M24

3 Planning The planning for a new or expanded reclaimed-water system is a critical element in implementing an efficient and effective water reuse program for any community. There is a great deal of important in formation to take into account whe n establishing a water reuse system. It begins with establishing the ty pes of potential reuse applications to be considered, the applicable regulatory requirements for the intended reuse, potential customer locations and demands, future developmen t planned for the study area, existing facil ities that could be utilized, opportunities for coor dinating design and construction with other projects in the a rea, a nd local expectation s. This chapter provides g uidance for the development of a facilities planning assessment for water reuse in a community.

GENERAL PLANNING CONCEPTS _____________________________ Strategies for p lanning a community reclaimed water system may vary for new or growing communities versus those that might be considered for older, established communities with in-place infrastructure. For new or growing communities, the planning must look into the future and consider the water reuse potential for all practical uses, which may range from irrigation to toilet flushing, industrial use to commercial applications, and a wide variety of other possible reuse opportunities. The facilities required to meet these reuse requirements may take on a variety of forms ranging from a more centralized approach by a dding advanced treatment to an existing centralized facility to constructing a new small footprint satellite facility. Zoning of the various sections of the anticipated growth areas will drive the potential for reuse, and often drive the location and type of facility to serve the va rying needs of a new community . For older communities with established infra structure, the planni ng may take a di fferent course. A market study wil l most certai nly need to be completed to ascertai n what potential reclaimed water needs exist in the community. The location of existing infrastructure may create design opportunities or constraints. The i mpact of potential zoning changes and the possibility of in-fill development will need to be considered. Whether for a new or older community, the development of a Reclaimed Water Master Plan is critical to the successful implementation of a water reuse system.

31 Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

32

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Developing the Reclaimed Water Master Plan A master plan approach is necessar y to develop a comprehensive overview of all essential components to implement a large reuse distribution system. Key components of the master plan include: source identification, customer identification and associated demand (market study), hydraulic modeling of the distribution system, identifying costs and rate structures to recover development costs, updating a community’s design and construction standards to include reuse facilities, developing a reuse ordinance to set the community’s policies governing the development of the reuse system, and permitting of the reuse facilities. When this is complete, a public awareness and information program may be undertaken to inform and educate the public abo ut the plan and how it will i mpact the community and the citizens indiv idually. Master planning must consider a variety of physical, economic, and legal issues associated with a water reuse project. Key to this process is the determination both of potential sources for reclaimed water and of potential markets for the reclaimed water. The project’s study area is first defined and alternatives for sources for the reclaimed water are considered. Institutional constrai nts and enabling powers that might affect reuse should be identified and assessed. Explorations of all possible options at this early stage will both establish a practical context for the plan and help to avoid creating dead ends in the planning process (USEPA 2004). In general, the following are the initial steps that are taken to define and refine the fundamental elements of a master plan. •

•

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Estimate the demand for reclaimed water from future customers resulting from redevelopment or new development.

•

Assess possible sources of will reclaimed water,tothe quality that supply, and thethe level of treatment that be required ensure thatofthe reclaimed water that is produced will meet the users’ requirements. •

•

•

•

•

•

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Perform a market study to determine the potential demand for reclaimed water in the community. Suggested factors to evaluate when talking with the potential customer are included in Table 3-1 and include the quantity and quality of the reclaimed water needed, timing, and other factors.

Establish the volume of reclaimed water to be made available (from either existing sources or new facilities). This would include such factors as diurnal flow patterns of both the supply and demand (customers). The seasonal patterns of reclaimed-water supply and demand also should be reviewed. Consider long-term effects and changes in the amount of wastewater generated and its impact on the availability of water for reuse. Determine the type of storage requirements that may be required for the project. Determine potential pipeline routes, pump stations, and storage for the reclaimed-water distribution system based on the location of reclaimedwater facilities and demand nodes. Consider construction of the reclaimed-water system based on when supply equals demand. Consider jurisdictional issues as part of the planning process, particularly when there are water rights issues involved.

Not for Resale

PLANNING 33

Table 3-1

Typical survey form to ascertain interest in water reuse Example City Water Reuse (or Potential) Customer Survey

Surveyor: _______________________________ Date: ___________________________________ Time: ___________________________________ Business Name _______________________________________________________ Contact Name _________________________________________________________ Physical Address ______________________________________________________ Mailing Address _______________________________________________________ City ___ ________________________________ State _____________________ Do you own or lease this property?

Zip ________________

•



: ________  Own Lease: _______ Phone Number ___________________________ Fax Number __________________________ Email ________________________________________________________________ Are you familiar with reclaimed water, what it is, how it is used, and its benefits? ____ Yes ____ No (If yes, explain what it is.) __________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ Please estimate your daily potable water consumption: (gallons per day) _______ Please estimate your daily nonpotable water consumption: (gallons per day) _______ What is/are your current source(s) of water (city, well, pond, other)? _________________________________ Is the demand at your facility continuous or batch process? ________________________________________ Is the demand at your facility seasonal? ____ Yes ____ No  If so, when is the peak season? ___________________________________________  About how long does peak season last? ____________________________________  When is the low season? ________________________________________________  About how long does the low season last? ___________________________________ If reclaimed water was made available at your facility, would you use it? ____ Yes ____ No If no, why not? __________________________________________________________________________ •

•

•

• • •

•

__________________________________________________________________________________________ __________________________________________________________________________________________ If reclaimed water was made available at your facility, how much water could you utilize on a daily basis? ______________________________________________________________________________________ What are the potential uses of reclaimed water at your facility (irrigation, cooling tower, process rinse water)? ______________________________________________________________________________________ If notified by Example City that reclaimed water would be available at your facility, how much lead time would you need to implement a reclaimed water system? ______________________________________________ ______________________________________________________________________________________ What quality of reclaimed water would be required for your intended use? (e.g., pH, suspended solids, dissolved solids, nitrogen) _________________________________________________________________ ______________________________________________________________________________________ What concerns might inhibit your facility’s usage of reclaimed water? _________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ What would be a reasonable cost for reclaimed water (check one):  Identical to potable water rate ___  75% of the potable water rate ___  50% of the potable water rate ___  25% of the potable water rate ___ Would you be interested in receiving more information on reclaimed water?____________________________ Comments _________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ •

•

•

•

•

•

•

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

34

PLANN ING FOR THE DISTRIBUT ION OF RECLAI MED WATER

Ideally, the master plan will identify the primar y elements of the pro ject, such as the necessary source of supply, treatment, storage, and possible distribution system layouts. Funding options are generally discussed, user costs developed, and a comparison made between the unit costs of potable water and reclaimed water for comparison purposes. Such a master plan provides a sound basis for review by the public as well as the many project participants and fu nding and regulatory agencies (Asano 1998). The following sections further develop the key concepts of the master plan.

RECLAIMED-WATER SUPPLY _________________________________ A community’s demand on the potable-water supply can be supplemented by reclaimed water. The additional water supply may come from procuring reclaimed water at a central wastewater treatment plant to tapping into the collection system at a location within a community to develop a decentralized satellite system. It could also include harvesting and treating stormwater runoff. Figure 3.1 and 3.2 illustrate the two primary sources of reclaimed water — from an existi ng centralized treatment facility (see Figure 3-1), or from a satellite facility (see Figure 3-2). The location of potential supply sources relative to potential customer locations is a critical planning factor. Supply sources for conside ration are existi ng wastewater treatment plants as well as planned future treatment facilities. The cost of the infrastructure to distribute the water, in addition to the long-term operating cost to move the water from the treatment location to the customer, can be significant. The topography of the area also impacts t he cost of transporting t he reclaimed water from the treatment location to the customer. Transporting the water through significant elevation changes impacts the pumping a nd storage considerations. Regulatory requirements are also an important consideration and establish minimum standards for treatment of reclaimed water based on the intended use. In addition, customers may have specific and unique water quality requi rements that sho uld be taken into consideration whe n planni ng a system. ` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

Figure 3-1

Centralized reclamation facility

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

PLANNING 35

Figure 3-2 Decentralized (satellite) reclamation facility

Demand Projections The suitability of using hi storical data for this purpose is questionable where major changes are anticipated. Potable-water and nonpotable-water demands are specific to geographic location, type of user, and many other factors. Water conservation plays an increasingly important role in total water-demand management and may result in a stabili zation or decrease in average per capita potable-water use. However, the increase in available supply from water conservation is li mited, and a dual system can represent a long-term solution by delivering nonpotable water for appropriate uses. For existing customers, the reclaimed-water market assessment should utilize potable water consumption data from the utility providing potable water to customers in the study area defined for the project. Consumption data for several of the most recent years should be rev iewed to ensure that the data are not skewed ba sed on a particu larly wet or dry year. This is especial ly critical for irrigation applications. Also, reviewing several years of data enables the proper assessment of the stability of a potential customer’s potable-water usage. An average annua l potable-water consumption for each customer can be developed, using the consumption data. To calculate the estimated average nonpotable-water demand, the average annual potable-water consumption should be multiplied by the estimated percentage of potablewater demand that can be supplied with reclaimed water. This percentage is based on the customer’s use of potable water. Data regarding the type of customer receiving the water can be obtained from the water utility, using the customer’s Standard Industrial Code (SIC) and land use zoning. For example, a golf course may be expected to use as muchreclaimed as 95 percent of its potable water for irrigation. This 95 irrigation could be met with water. Therefore, for planning purposes, percentdemand of the golf course’s existing average demand should be used for the reclaimed-water demand for a reclaimedwater project. Similarly, for a commercial user, it may be expected that 40 percent of the potable-water demand is used for irrigation and toilet water flush ing. Both of these uses

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

36

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

are suitable for reclaimed water. Therefore, for planning purposes, 40 percent of the commercial user’s existing average demand could be used for the reclaimed-water demand for a reclai med-water project. All potential users must be contacted to determine water quality and quantity requirements, operating requirements, delivery pressures, points of connection, and existing plumbing and facility layout. Severa l methods can be used to identify and survey potential reuse customers for the potential demand that may exist for reclaimed water. For established communities, an initia l step is to evaluate a community’s water meter sales records for potential reuse customers. Data from all large water meters (1 in. or 1 ½ in. and larger) should be compiled for both a dry and a wet year, and the data should be normalized to assess the impact of climate on the projected water use. If existing irrigation meters are installed, t he data should be segregated by potable-water meters and irrigation meters. In a recent planning study for Raleigh, N.C. (the capital of North Carolina with a population of 360,000 in 2007), the records indicated that there were almost 3,500 large water meters with an average daily demand of 24 mgd. Approximately 300 irr igation meters registered an average daily demand of 1 mgd or greater (Black & Veatch 2006). Typically, the largest total water users and irrigation meter sales are identified and surveyed. The survey could consist of a simple questionnaire exploring what opportunities the customer saw for using reclaimed water (see Table 3-1). Experience indicates that it is also useful to call 10 percent of the potential surveyed customers to collect more information after the sur vey is returned. A l isting of potential customers for each type of reclaimed-water use is developed, and telephone interviews conducted to as sess potential reuse demand. In areas where a number of golf courses serve the area residents, each should be contacted individually to encourage their use of reclai med water. The community should also examine its own potential for water reuse. In new communities, or in areas of expansion in a community, existing customers do not exist, so it is necessary to use zoning maps a nd a community’s comp rehensive plan to make projections of future demand in the identified area(s). Such demand projections are obviously tied to land use, but they are also related to a community’s interest and adopted regulations regarding the required of reclaimed water. Ifwill a community pushes the use of reclaimed water,use their potential demand be higher. aggressively Some communities may employ mandatory use ordinances to require reclaimed-water use in special cases. City and county planning agencies typically have information regarding new development and redevelopment that are planned for their jurisdictions. Env ironmental documents on file with local agencies are additional sources of information regarding future construction projects. Dual plumbing new construction projects for reclaimed-water use is much more cost-effective than retrofitting a site after constr uction has been completed . Therefore, future customers are typically excellent candidates for reclaimed-water use. By working with the developers of new construction and reconstruction projects in their plann ing stages, new customers can be cu ltivated at min imal cost, thereby increasing the cost-effectiveness of the reclaimed-water project. In summa ry, there are a variety of data that need to be considered. •

•

•

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

The quality of the supply for the reclaimed water and the level of treatment that will be required to ensure that the quality of the reclaimed water will meet the users’ requirements. The estimated percentage of that eachcould potential reclaimed-water existing potable-water demand be met with reclaimedcustomer’s water. The estimated demand for reclaimed water from future customers resulting from redevelopment or new development.

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

PLANNING 37 •

The volume of reclaimed water available and its diurnal pattern, as well as the users’ diurnal usage patterns. The seasonal patterns of reclaimedwater supply and demand also should be reviewed. Information on both the diurnal and seasonal patterns will assist in determining the type of storage requirements that may be required for the project. This storage may occur at the utility’s facilities, at satellite storage facilities, or at specific customer locations.

All of these factors are considered by specific reclaimed-water use category as described in the following section.

Demand Estimates by Use Category Potential large-quantity users must be contacted to determine water quality and quantity requirements, operating requi rements, delivery pressures, points of connection, and existing plumbing and facility layout. A form or questionnaire will help the interviewer assemble essential design in formation, as previously noted in Table 3-1. Urban uses. Nonpotable water may serve a variety of uses in an urban waterservice area. Table 3-2 lists urban demand categories of residential, industrial, public, commercial, and unaccounted-for water uses. An estimated percentage of daily use in these categories is provided in Table 3-3. The amount of water used in urban potablewater systems varies from system to system but averages approximately 160 gal per capita per day (gpcd) (605 L/d per capita). Each of the categories has some uses that can be met with nonpotable water. Indoor residential use. A comprehensive study (Mayer et al. 1999) funded by The American Water Works A ssociation Research Foundation (AwwaRF) determined the indoor residential water uses in various categories shown in Tables 3-4a and b and 3-5. Various researchers have determined indoor residentia l water demand (see Table 3-5) for eight categories: toilet, clothes washer, bathing (shower and bath), faucet, leaks, other domestic, and dishwasher. The average total demand is approximately 69.3 gpcd (262 L/d per capita). High-qual ity potable water is required for drinki ng, cooking, bathing, showering, laundry, and dishwashing—about 60 percent (42 gpcd) (157 L/d per capita) of the total indoor household demand. The remaining 40 percent (28 gpcd) (105 L/d per capita) of indoor residential water is used mostly for toilet flushing (and leaks).

Table 3-2

Urban water demand categories

Interior Residential

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Toilet flushing Bathing Laundry Dishwashing Drinking and cooking Miscellaneous

Exterior Residential Irrigating Car washing Swimming pools Cleaning

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Industrial Manufacturing Processing Cooling

Public Schools Prisons Hospitals Parks and fountains Public buildings Median and right-of-way landscaping

Not for Resale

Commercial

Unaccounted-for

Office buildings Hotels Restaurants Car washes Laundries Golf courses Cemeteries Shopping centers Retail businesses Construction (concrete water, dust control)

Leakage and loss Fire hydrant usage Testing Flushing Meter underregistration Street cleaning

38

PLANN ING FOR THE DISTRIBUT ION OF RECLAI MED WATER

Table 3-3

Urban water demands as a percentage of average daily use Category of Use

Source McPherson 1976 California DWR 1976 Linaweaver, Geyer, and Wolf 1966 Haney and Hamann 1965 USPHS 1967

Residential Commercial Industrial Public % % % % 33 12 33 7 68 10 18 4 50 43 41

Fair, Geyer, and Okun 1968 33 Bostian 1974 46 Hirshleifer, DeHaven, and Milliman 1960 Murray and Reeves 1972 38 US Water Resources Council 1976 Frey, Gamble, and Sauerlender 1975 AWWA 1970 and 1965 Weston National Water Utility Survey (Deb 1978) Pennsylvania Water Utility Survey (Deb 1978) Smith Australia 1998 50 Santa Cruz Water Management Plan 2000 Alameda County Water District 2000 Las Vegas Valley Water District 2002 D. Ziegielewski Southern California 1993

19 18 13

25 24

17

45

13 17 7

25

17

12

150

150

(568) (568)

18

32

46

18

23

13

(628) 157 (594)

49

12

21

18

166

(628)

42 52

18 17

22 15

18 7

9

179 153

(677) (579)

39

12

31

5

14

162

(613)

32

5 30

10

20

166

5

15

175

61

19

11

2

7

60

14

12

6

8

65

24

1

5

5

59

19

6

7

9

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Total Flow Unaccounted(L/d per for % gpcd capita) 15 160 (605)

Not for Resale

PLANNING 39

Table 3-4a Percentage of average indoor gallons per capita per day usage, 12 study sites StudySite Seattle SanDiego Boulder Lompoc Tampa WalnutValleyWD Denver LasVirgenesMWD

Toilet 29.9% 27.1% 30.6% 25.2% 25.4% 26.5% 30.4% 22.6%

Clothes Washer 21.0% 28.0% 21.6% 23.3% 21.6% 20.8% 22.5% 24.1%

Shower 20.0% 15.4% 20.2% 16.9% 15.5% 17.3% 18.6% 16.4%

Faucet 15.2% 18.5% 17.9% 15.0% 18.2% 18.1% 15.2% 16.1%

Leaks 10.3% 7.9% 5.3% 15.3% 16.4% 11.2% 8.4% 16.1%

Other Domestic 0.0% 0.5% 0.3% 1.4% 0.5% 3.4% 0.7% 1.6%

Bath 1.9% 0.9% 2.2% 1.8% 1.7% 1.5% 2.3% 1.9%

Dishwasher 1.8% 1.5% 2.2% 1.2% 0.9% 1.2% 1.7% 1.3%

Waterloo&Cambridge Phoenix Scottsdale&Tempe Eugene 12studysites

28.8% 25.3% 22.6% 27.4% 26.7%

19.4% 21.8% 17.8% 20.5% 21.7%

11.8% 16.1% 15.5% 18.1% 16.8%

16.1% 12.4% 13.8% 14.3% 15.7%

11.6% 19.1% 21.6% 16.3% 13.7%

8.5% 2.8% 6.1% 0.1% 2.2%

2.7% 1.5% 1.1% 1.8% 1.7%

1.1% 1.0% 1.4% 1.7% 1.4%

Table 3-4b Average indoor gallons per capita per day usage, 12 study sites StudySite Seattle San Diego Boulder Lompoc Tampa WalnutValley WD Denver LasVirgenesMWD Waterloo&Cambridge Phoenix Scottsdale&Tempe Eugene 12 study sites ` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Table 3-5

Toilet 17.1 15.8 19.8 16.6 16.7 18.0 21.1 15.7 20.3 19.6 18.4 22.9 18.5

Clothes Washer 12.0 16.3 14.0 25.3 14.2 14.1 15.6 16.8 13.7 16.9 14.5 17.1 15.0

Shower 11.4 9.0 13.1 11.1 10.2 11.7 12.9 11.4 8.3 12.5 12.6 15.1 11.6

Faucet 8.7 10.8 11.6 9.9 12.0 12.3 10.5 11.2 11.4 9.6 11.2 11.9 10.9

Leaks 5.9 4.6 3.4 10.1 10.8 7.6 5.8 11.2 8.2 14.8 17.6 13.6 9.5

Other Domestic Bath 0.0 1.1 0.3 0.5 0.2 1.4 0.9 1.2 0.3 1.1 2.3 1.0 0.5 1.6 1.1 1.3 6.0 1.9 2.2 1.2 5.0 0.9 0.1 1.5 1.6 1.2

Dishwasher 1.0 0.9 1.4 0.8 0.6 0.8 1.2 0.9 0.8 0.8 1.1 1.4 1.0

Potential reuse demands

TypeofReuse Golf course irrigation Agricultural irrigation Industrial Commercial Nurseries Institutional Schools Recreation Residential Total

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

NumberofUsers 20 2 19 17 20 11 28 5 2 developments, 1,300 home sites 124

Not for Resale

PotentialReuseDemand,gpd 1,000,000 3,700,000 350,000 200,000 500,000 425,000 300,000 350,000 625,000 7,450,000

40

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Outdoor residential use. Outdoor residential water demand varies with the season and geographical area. For example, on an average daily basis, outdoor use amounts to seven percent of residential demand i n Pennsylvania and 4 4 percent in California. D uring July and August in Denver, approximately 80 percent of all potable water is used for lawn irrigation (USEPA 1992). Reclaimed water can be used, almost exclusively, to supply this outdoor demand. Commercial use. This urban category includes buildings, landscaping, lakes and impoundments, and construction. Buildings . Commercial and public office buildings offe r opportunities for nonpotable-water uses such as air conditioning and toilet and urinal flushing. These uses constitute 80 to 90 percent of the total water usage for large commercial centers. High-rise office buildings have the greatest potential for flushing-water use, because toilet facilities are centrally located on each floor and a re mostly in the sa me location for all floors. This allows for a common riser and feed and short piping runs. Water demand for high-rise office buildings is a function of the number of employees or toilet fixtures. Whether a building uses low-volume flush toilets, a flush-valve system, or waterless urinals will have an impact on the demand. Specific demand information is available in building or plumbing codes or from water -meter data for existing buildings. Land scaping irrigation. By far the largest urban use of nonpotable water is for landscape irrigation. For commercial properties, this is particularly true for those in the more campus-like setting. Irrigation demands depend on rainfall, runoff, evapotranspiration, soils, geohydrology, vegetation, and local practices. Historical records are usually available to estimate demand. Checking the irrigation water use of adjacent office parks may also serve as a good guide for projecting irrigation needs of a new development. Local regulations may have an impact on the design demand rates by dictating when certain areas may be irrigated. Because the daily water requirement is applied in only a few hours, the rate of demand can easily triple the average for the day. A municipality may require large commercial (or industrial) irrigation customers to provide off-line storage ( a site amenity such as a pond or storage) to reduce the peak need for reclaimed-water use.

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Ordinances requiri ng Principal xeriscaping arefor alsoreclaimed becomingwate more Construction. uses r inprevalent. the construction industry include watering gravel roads and haul roads for dust control and cleanup, increasing the moisture content of earthwork to improve compaction, mixing concrete, curing concrete, and washing down at construction sites. These uses have few quality requirements other than bacteriological safety. Water used for mixing concrete must contain no materials or minerals detrimental to concrete. As a rule, unless t he water contains excessive amounts of chlorides or sulfates, most raw or reclai med water is suitable for concrete mixing. Estimating the quantity of water for design purposes is difficult and is best done using historical data. Most uti lities keep records of construction water-me ter deposits and charge for “hydrant” water. This in formation is useful in projecting future demands. A concrete ready-mix operation is a large user of water for concrete mixing, truck washdown, aggregate washing, and moisture control. Demand estimates ca n be based on the amount of concrete sold, the amount of aggregate purchased, the aggregate’s moisture deficiency, and the number of trucks in the fleet.

Municipal Uses Irrigation.

Irrigation in the municipal setting include cemeteries, parks, play-

grounds, school yards, street and freeway medians, nurseries, tree farms, golf courses, and building grounds. Frequently, many of these areas include impoundments either for storage or decorative purposes. Local regulations may have an impact on the design demand rates by dictating when certain areas or crops can be irrigated. Parks, playgrounds, school yards, and golf courses

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

PLANNING 41

are typically irrigated at night. Because the daily water requirement is applied in only a few hours, the rate of demand can easily triple the average for the day. Balancing the quantity of water in reservoirs and golf-course water hazards and scheduling water use at the demand site can mitigate this problem and reduce the size of delivery mains. Lakes and impoundments. The quantit y of water needed to offset evaporation from lakes and impoundments can easily be estimated from local meteorological pan evaporation data. Because these water bodies tend to be shallow, evaporation losses more closely correspo nd to pan evaporation than to deep-lake or reser voir evaporation.

Industries Demand for cooling-water makeup, or process rinse and washwater varies by industry type and size. For example,power the cooling-water makeup requirement forML/d). a 40,000-barrels/ day oil refinery or 250-MW plant is about 1 to 2 mgd (3.8 to 7.6 Cooling-water makeup. Cooling water is one of the largest water uses at a typical industrial facility (see Figure 3-3). Water quality depends on the geographic area of the country where the industry is located, and the water must be of a reasonable quality. Certain constituents in reclaimed water decrease the number of cycles of concentration and increase corrosion and chemical costs. The municipality should consult with the industry about water-quality needs and correlate that with the water quality of the reclaimed water. Based on the water characteristics and the “tonnage” of cooling towers at a particula r facility, the industry can estimate its makeup water requirement. Cooling-water use is site-specific and depends not only on cli mate and water chemistry but also on the manufactur ing operation itself. A facility that operates three shifts per day may have a substantially different water demand and water-use pattern than a facility that operates only one shift per day. Identifying the purpose of the cooling-water makeup is important. For example, is t he use strictly for building cooling, or is it used to cool compressors and other manu factur ing equ ipment? Process rinse and washwater. Large quantities of water are used in some manufacturing operations and the demand for process water that can be replaced with reclaimed water is very industry-specific. These qua ntities of reclaimed water use can often be quite high and are also an excellent base load. Industries within the municipality will have to be individually surveyed to ascertain their interest in reclaimed water as a substitute for certain process waters.

Figure 3-3 Cedar Bay Power Plant (Jacksonville, Fla.) is provided reclaimed water for cooling

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

42

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Most industries believe that i nternal recycling of wa stewater is more cost-effective than purchasing reclaimed water from an outside source. The reason fo r this is that industries are required to treat or pretreat their wastewater befo re discharge. Internal recycling minimizes the amount of wastewater requiring treatment. When a particular application is identified, the industry must identify the specific uses, estimate the average and peak demands (both on a dai ly and seasonal basis), consi der the manufacturing operation, consider the number of shifts, and the potential for production cutbacks or growth.

Other Uses

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Agricu ltural uses. On the fringes of many urban areas, crops are being raised that can be irr igated with reclaimed water . Demand will vary seasonal ly and will depend on the same factors mentioned for lawn or golf-course irrigation. Agricultural irrigation represents about 40 percent of the total demand nationwide. In Orange County, Calif., the Irvi ne Ranch Water District provides reclaimed water to irrigate approximately 2,000 acres (8.09 km2) of urban landscape and 1,000 acres (4.05 km2) of mixed agricultural lands (orchards and vegetable row crops). As agricultural land use is displaced by residential development, the district has the flexibility to convert its agricultural demand to urban uses (USEPA 2004). Aquaculture uses. The use of reclaimed water for aquaculture is increasing. Demand is a d irect function of the fish being raised, the size of the ponds, and the amount of other water sources available for supplementing the ponds. A recent proposed application in Thailand, south of Bangkok, would use nearly 100 mgd of treated effluent for supplementing the ponds (Black & Veatch 2007).

Service Area The development of a reclaimed-water system involves linking these sources of supply (generally a wastewater treatment plant [WWTP]) with the located customers. There are, however, other considerations for defining the service area for a project which include •

The projected growth of reclaimed-water demand;

•

The volume of reclaimed water available;

•

•

•

•

The location of the reclaimed-water supply relative to potential large users of reclaimed water; The potential land availability for treatment, storage, and pumping facilities; The hydraulic and construction factors that will influence design and construction; and The opportunities for partnering with other agencies.

Assessing all of these factors and superimposing them on the existing potable-water distribution system can provide an excellent overview of the potential scale and scope of a reclaimed-water system. With the advent of GIS, and the geo-positioning of the elements such as existing water meters and other facilities, the layout and design of the reclaimedwater system is much less complex.

RECLAIMED-WATER SYSTEM TYPES ___________________________ Urban water distribution systems were introduced in the early 19th century, but for firefighting, not for drinking water. Small fires often grew to conflagrations. The demand for water distribution systems for fire protection provided the impetus for urban water

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

PLANNING 43

distribution systems. Only much later were water supply services extended to commercial and residential properties.

Drinking Water Systems with Fire Protection To this day, the standards a nd regulations for all drink ing water distribution systems have been promulgated by a succession of fire insurance agencies. It was once the National Board of Fire Underwriters. Currently, it is the Insurance Services Office, Inc. Typically, as engineers, the design objective is to providing safe drinking water systems. It is of utmost importance to select water resources of high qual ity and to provide adequate drinking water treatment. However, the design of the water distribution systems that carry the water to consumers is based entirely on providing adequate flows of water for fire protection, with to nohas attention to dri nking waterofqual ity. Onlylittle recently a concern for the impact distribution systems on drin king water quality emerged. In 2004, AWWA published the book Water Quality in the Distribution System , which pointed out issues with distribution system water quality. However, none of the many publications describing water quality problems and di stribution systems make any connection with the fact that the design of the distribution systems has been dictated by the need for fire protection.

Nonpotable Systems without Fire Protection Urban dual distribution systems have been around since AD 10 when Caesar Augustus constructed the major aqueducts to supply fountain water. Substitution of lower quality water for nonpotable purposes to preserve limited resources of high qua lity water remains one of the two primary purposes of dual distribution systems, the other being an alternative for wastewater disposal. The layout and des ign of a dual di stribution system is very similar i n nature to that of the potable system. The only significant difference is that the capacity of the system is not dictated by fire flow requirements, but rather by the demand for nonpotable-water uses.

Potable Systems without Fire Protection Community dual water systems a re widely accepted in the United States and i ncreasingly so in other countries. They have proven to be an approach that is successful and economical, saving drinking water by reclaiming wastewater for myriad nonpotable purposes. A new paradigm for consideration would be to continue to use dual systems but reverse the design criteria to one system used exclusively for drinking water and the other for all nonpotable purposes, including fi re protection. There is in fact one such dual system in place today: Rouse Hill, a suburb of Sydney, Australia . The speci fic pur pose of the design of the system is for the maintenance of the quality of their drinking water. The first stage, for over 100,000 people, is a dual system with small pipes for drinking and showering. The other system is for nonpotable uses such as irrigation, toilet flushing, air conditioning, and fire protection that are served by large pipes for reclaimed water. Another import ant advanta ge of this approach is that t he dr inking water treatment plants could be smaller tha n tra ditiona lly required, if fire protection were to be provided via reclaimed water. A layout for a dual system for a new communit y providing a dri nking water distribution system for only drinking, w ith the second system providing reclaimed waters for all nonpotab le purposes, including fire protection, is illustrated i n Figure 3 -4.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

44

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

Figure 3-4 Dual distribution system for a new community

DEVELOPMENT OF DISTRIBUTION SYSTEM OPTIONS ____________ Water reclamation starts with a source of supply. Reclaimed water for the distribution system must srcinate from a source. These sources are generally from a WWTP or a satellite facility located within the wastewater collection system. Treatment systems to produce reclaimed water are governed by regulations and guidelines are developed by each state as noted in Chapter 2. Typically, they focus on acceptable concentrations of biodegrad-

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

able organics, suspended solids, dissolved solids, and pathogens in the reclaimed water. These acceptable concentrations may vary depending on the intended use of the reclaimed water. While the required treatment process for the wastewater depends on the highest use of reclaimed water in the system, reclaimed water is usually treated to meet unrestricted urban reuse, which requi res the highest level of treatment. In many potable-water systems, exi sting raw-water supp lies may requi re additional treatment to meet the increasingly stri ngent requiremen ts of the Sa fe Drinking Water Act. Instead of providing centralized treatment plants, it may be preferable to use satellite potable-water treatment plants to provide additional treatment for the fraction of total water demand used for drinking and cooking. In areas where a large amount of water is used in a relatively small area, such as condominiums, high-rise residential buildings, or commercial facilities, satellite potable treatment plants can be built on-site to provide additional treatment. In the development of a dual distribution system in an existing community, potable water would be supp lied through a new separate distr ibution system within the area. The existing water system would be used for supplying nonpotable water for all other uses within the area. Planning studies should be conducted to de termine the optimal locations of such facilities in the existing d istribution system. Satellite wastewater treatment facilities can also be designed to provide adequate reclaimed water at a point-of-use location, rather than depending on a more centralized (and remote) advanced wastewater treatment plant. Consideration of such decentralized systems are based on a va riety of factors, but gen erally are dr iven by economics. Once a treatment program (or programs) has been developed, to fully analyze the

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

PLANNING 45

various distribution system options that may be available for a reclaimed-water project, a map of the study area should be developed that includes the following information: •

•

•

The location of the proposed reclaimed-water treatment facilities; The location of existing and future customers identified as large potential users of reclaimed water; The location of existing rights-of-way, such as roads and major transit systems;

•

General elevation information regarding the study area; and

•

City and county boundaries.

this map, a var iety of tools can be locations used to lay out various distribution system plans,Using including the identification of potential for pump stations or for reservoirs. Pipe sizes wil l be determined based on the design cr iteria established for the pro ject. While it is recognized that each reclaimed water project will have unique projectrelated requirements, it is nevertheless help ful for a util ity to develop standardized design criteria to assist i n design of the system. Criteria should include peaking factors; storage requirements; pump station sizing; minimum and maximum delivered reclaimed-water pressure; m inimum and maximum velocity of recla imed water in the distribution system; estimated percentage , based on customer type, of potable-water demand that can be supplied with reclaimed water; and water delivery reliability. The development of specific design criteria is described in more detail in Chapter 5. All of these criteria become a part of the process to model the distribution system.

IMPLEMENTATION _________________________________________ The master planning effort also must include a number of elements that are essential to implementing a successful reuse program. There are a number of general considerations that must be considered in addition to permitting, rates, design standards, and a reuse ordinance, all of which are discussed in Chapters 6 and 7. The utility must first fi nalize the master plan, summa rizing the fi ndings, the economic analysis, the recommendations and phasing plan and other pertinent considerations. The plan generally will include at least the following: •

•

•

•

•

•

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Potential pipeline routes and major locations of other facilities for the reclaimed-water distribution system, including consideration of pump stations, major pipeline routing, and storage locations that may require land acquisition; Land acquisitions that may be required to construct the necessary treatment or storage facilities (either centralized or satellite); Costs for potential alternatives that include capital costs, planning costs, design costs, construction costs, customer retrofit costs, and operations and maintenance costs; The present and projected cost for potable water and a comparison of those costs with the anticipated cost of reclaimed water (a comparative rate study); The required permits; Agreements needed with other agencies to ensure adequate reclaimed water supplies;

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

46

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

•

•

Agreements that may be needed with specific customers to ensure long-term customer demand for the reclaimed water; and Interagency agreements.

Once the master plan has been completed, it is absolutely critical that a series of public hearings or public meetings and other such informational sessions be held to conve y to the public the major findings. The public, through an honest and open pub lic dialog, wil l be able to provide the utility with comments and suggestions for improvement.

CONCLUSIONS ____________________________________________ The master plan isis afor guideline for the development of a reclaimed-water system. ap-l proach described a community that is just beginning. Many communities haveThe partia systems already installed, therefore portions of this process will be redundant. Overall, the objective is to develop total project costs for a variety of options for the reclaimedwater system, to optimize the number of customers served, and to keep the project costs reasonable. Political and institutional considerati ons will a lso play a part. This i s an iterative process, linked to discussions with customers that may result in reasonable options or new project options that should be added for consideration. Through the process, the community must keep an open mi nd to all possible project scenarios to arr ive at the most cost-effective project.

REFERENCES _______________________________________________ Ala meda County Water Distr ict. 2000. Water Management Plan . Alameda County, Cal if. American Water Works Association. Operating Data for Water Utilities 1970 and 1965. AWWA Statistical

Rept. 20112. New York City, N.Y. Asano, T. 1998. Wastewater Reclamation and Reuse . La ncaster, Pa.: Technomic Publishing Co., Inc. Bostian, H.E. 1973. News of National Environmental Research in Cincin nati. Cincinnati, Ohio: USEPA. . 1974. Water Conservation by the User. APWA Reporter (July 1974). Kansas City, Mo. California Department of Water Resources. 1976. Water Conservation in California. Bull. 198. Sacramento, Calif. California State Water Resources Control Board, Office of Water Recycling. April 17, 1997. Water Recycling Funding Guidelines . Sacramento,

Calif.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Camp Dresser & McKee Inc. Crook, J., D.K. Ammerman, D.A. Okun, and R.L. Matthews. 1992. Guidelines for Water Reuse . Cambridge, Massachusetts: Camp Dresser & McKee Inc. Crook, J. 1984. Water Reuse in California . AWWA Water Reuse Symp. Denver, Colo.: American Water Works Association. Deb, A.K. 1978. Multiple Water Supply Approach for Urban Water Management . Report submitted to the Na-

tional Science Foundation. NSF ENV 76-18499. Arlington, Va. Dziegielewski, Benedykt et al. 1993. Evaluating Urban Water Conservation Programs: A Procedures Manual, Planning, and Management Consultants, Inc. Denver, Colo.: Ameri-

can Water Works Association. Eingold, J.C. and W.D. Johnson. 1984. St. Petersb urg’s Wastewater Recl amation and Reuse Project—Eight Years Later. AWWA Water Reuse

Symp. Denver, Colo.: American Water Works Association.

PLANNING 47

Fair, G.H., J.C. Geyer, and D.A. Okun. 1968. Water and Wastewater Engineering, Vol. 1. New York, N.Y.: John Wiley and Sons Inc. Goff, D.G. and P.L. Busch. 1984. The Chandle r (Arizona) Story: Development Through Water Reuse. AWWA

Water Reuse Symp. Denver, Colo. Haney, P.P. and C.L. Hamann. 1965. Dual Water Systems. Jour. AWWA, 50(9): 1073. Denver, Colo. Hirshleifer, J., J.C. Dehaven, and J.W. Milliman. 1960. Water Supply Economics: Technology and Policy . Chicago, Ill.: University of Chicago Press. Las Vegas Valley Water District, 2002. Water Management Plan . Las Vegas, Nev. Linaweaver, F.P. Jr., J.C. Geyer, and J.B. Wolff. 1966. Resid ential Water Use. Washington, D.C.: Federal Housing Administration, Department of Housing and Urban Development. Mayer, P.W., W.B. DeOreo, et al. 1999. The Residential End Uses of Water . Denver, Colo.: Awwa Research Foundation/American Water Works Association. McPherson, M.B. 1976. Conservation in Household Water Use. Presented at the Conference on Planning A lternatives for Municipal Water Systems. French Lick, Ind.: French Lick, Inc. Murray, R.C. and E.B. Reeves. 1972. Estimated Use of Water in the United States in 1970. US Geological Survey

Circular 676. Washington, D.C.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

National Research Council. 1998. Issues in Potable Reuse – The Viability of Augmenting Drinking Water Supplies With Recl aimed Water.

Washington, D.C.: National Academy Press. Rowny, A.C., D.L. Wright, and D.F. MacIntyre. 1987. Large Scal e Groundwater Recharge Via Infiltration Basins in Orange County, Fla . AWWA

Water Reuse Symp. IV. Denver, Colo.: American Water Works Association. Santa Cruz Water Department. 2000. Urban Water Management Plan, Santa Cruz City Water Conservation Office. Santa Cruz, Calif. Schorr, P.L. 1984. Industr ial and Commercial Reuse: Regional Econo mics and Institutions. AWWA Water

Reuse Symp. Denver, Colo.: American Water Works Association. Schroeder, L. 1986/1987. Baltimore and Bethlehem Steel: A 45-Year Partnership in Resource Reuse. Journal of Freshwater, p. 20. LaCrosse, Wis. Smith, D.I. 1998. Water in Australia: Resources and Management . Melbourne, Australia: Oxford Universi ty Press. USEPA. 1992. Guidelines for Water Reuse. EPA/625/R-92/004. Cincinnati, Ohio: USEPA, Office of Technology and Regulatory Support, Center for Environmental Research and Information. USGA. 1997. Wastewater Reuse for Golf Course Irrigation . Boca Raton, Fla.: CRC Press LLC (Lewis P ublishers).

This page intentionally blank.

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

AWWA MANUAL

Chapter

M24

4 Engineering Design — Treatment This chapter details the engineering issues that are generally considered in the design of treatment systems to generate reclaimed water. No design criteria or detailed design examples are presented. Such considerations are outside the scope of this manual and are better handled in other manuals. Such reclaimed water must be of sufficient quality for the intended use and in general will be for the highest intended use by any customer in the nonpotable-water distribution system. The issues discovered in this chapter include sources of nonpotable water and the treatment of those sources. Distribution, storage, and public health safeguards of the nonpotable water are discussed in Chapter 5.

SOURCES _________________________________________________ Sources of supply for a nonpotable-water distribution system include treated wastewater (reclaimed water), untreated or partially treated raw water otherwise available to produce potable supply, stormwater runoff, and groundwater. In Hong Kong, seawater is also used in a nonpotable system for toilet flushing. The most common nonpotable-water supply is reclaimed wastewater.

WASTEWATER _____________________________________________ Wastewater is generally available in proportion to the population of the area served by the collection system. Wastewater usually requires at least secondary treatment for disposal and tertiary or advanced treatment for release to some waters. Reclaimed water may have multiple quality designations dependent on type of use anticipated. Typical municipal wastewater •

Has a higher concentration of nutrients than surface waters;

•

Has higher dissolved solids than potable water; and

49 Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

50

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

•

Is generally available at the lowest elevation in the collection system, unless the treatment plant is sited upgradient in the collection system (a satellite facility).

Water rights can also be a factor of consideration, particularly if wastewater normally discharged to a watercourse is used by downstream users. Usually, reclaimed-water customers and downstream irrigation users need water during the same period of the year, which can create a conflict. Resolving this conflict should be addressed in the planning stages of a reclaimed system design.

Untreated or Partially Treated Raw Water A raw-water source potentially available for potable supply may have high organic, heavymetal, or dissolved-solids concentrations. Treating this water for potable use could be relatively expensive, yet the source may be of adequate quality for nonpotable uses with or without minor treatment (such as disinfection). Such sources are typically much lower in plant nutrients than wastewater. Unlike wastewater, the available amount of this raw water is not related to the service-area population, and it does not necessarily occur at lower elevations in the service area.

Nonpotable Surface Water (Stormwater Runoff) Stormwater runoff that would otherwise be lost to the local raw-water storage facilities can be captured, stored, treated, and used for nonpotable uses in a reclaimed-water system. Such sources may require diversion or well pumping. Nutrient and dissolved-solids concentrations will vary. Additional treatment or blending with other sources of supply to the reclaimed-water distribution system will most likely be required.

Selection of Sources of Supply The major issues in selecting and developing a source or sources of supply for nonpotable uses are cost-effectiveness and resource scarcity. If the cost of wastewater treatment required for disposal is substantial, the incremental increase in production cost for a reliable treated-wastewater supply for reuse may be relatively attractive. If the costs of initial or incremental raw-water treatment for high-quality potable requirements are relatively high, then the cost of a second distribution system for conveying nonpotable water throughout the service area for lower-quality needs may be relatively attractive. When the importation and production costs of the only available potable supply are relatively high, the cost of locally produced and distributed treated wastewater may justify substituting it for the potable supply for certain nonpotable uses. Any one or all of these elements contribute to making nonpotable reuse and dual distribution systems increasingly attractive.

SUPPLY VARIATIONS ________________________________________ Wastewater production varies from 50–150 gpcd (190–570 L/d per capita). An average value of 100 gpcd (380 L/d per capita) is often used for planning purposes. While all of the collected wastewater may be treated for use as reclaimed water, a small portion is lost through the treatment chain to sludge management, filter backwashing, and other plant operations. The quantities of other nonpotable-water source supplies available for use are site-specific, and there are no commonly accepted standards to be considered.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

ENGINEERING DESIGN — TREATMENT

51

Hourly Variations The peak hourly flow of wastewater typically ranges from 1.5 to 3.0 times the average flow, and the ratio of average to minimum flow is often greater than the minimum flow. Because of its derivation, wastewater flow is somewhat proportional to the hourly variation of potablewater demand. The influent peak flow to the wastewater treatment plant will typically lag behind the potable-water peak use as a result of the travel time in the collection system. On a daily basis, influent wastewater flows are often lowest during the period when the demand for reclaimed water is highest — the nighttime peak irrigation periods. There are no typical patterns of hourly variations in volume in other supply sources. The difference between hourly nonpotable distribution-system demand and the hourly availability of treated wastewater can be mitigated (1) by how the supply is obtained (a pumping or skimming operation that usually produces a relatively constant output flow from a satellite plant); (2) by use of on-site flow equalization (location in overall treatment chain determined by benefit/cost) or a clearwell providing storage just before pumping; or (3) by the use of off-site storage (operational storage reservoirs). The key factors in determining such storage volumes are the balance of treated-wastewater flow rates, the pumping rate from the plant into the distribution system, and system demand. System imposed irrigation use time limits (8 p.m. – 8 a.m.) can significantly impact storage and pumping requirements.

Seasonal Variations Wastewater-generation rates in resort areas and communities with large seasonal industries can vary greatly from month to month. However, in communities with typical cross sections of residential, institutional, commercial, and industrial sources, seasonal variations occurring monthly in wastewater flows are relatively small. They are generally not substantial enough to warrant mitigation for supply reasons alone. Seasonal-demand variations for certain types of reuse, such as irrigation, are generally large. Figure 4-1 illustrates the seasonal variations in St. Petersburg, Fla. (USEPA 2004). These variations requirecapacities. substantial seasonalanstorage or large increases or decreases in plant production Selecting option volumes is based primarily on the cost tradeoffs between excess plant capacity and seasonal storage. Seasonal storage for treated wastewater and other nonpotable supplies most likely would be provided in an open reservoir, but other options may be available. 1.4 e g 1.3 a r e v A l a 1.2 u n n A f o 1.1 n io t c a r 1.0 F ly th n 0.9 o M

Nonpotable Demand

Potable Demand

0.8 J

F

MA J

JM

N O S D A

Figure 4-1 Potable- and nonpotable-water use—monthly historic demand variation, St. Petersburg, Fla. (Adapted from USEPA)

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

52

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

Seasonal variations in daily flows from potable or other surface water and groundwater sources can be relatively great and depend on both seasonal and multiyear weather conditions. Some storage can be provided by good long-term management of surface water and groundwater supplies. The economic feasibility of a nonpotable distribution system depends on supplying water that satisfies or exceeds the requirements of the largest potential users in the service area with respect to issues such as water quality and pressure requirements. The smaller users have several choices, including the following: •

Connect to the system and use the reclaimed water “as is”;

•

Connect to the system and provide additional treatment on-site; and

•

Continue to use potable water. This treatment may be on-site phosphorus removal, ammonia removal (if necessary), softening, or reverse osmosis. For example, while the largest users in a system may be for irrigation, industry (typically a smaller user) may apply additional treatment.

TREATMENT FOR RECLAIMED WATER _________________________ Chapter 2 presents state water regulations and guidelines for the expected quality and treatment of reclaimed water. The major water-quality parameters to consider when selecting appropriate treatment to produce reclaimed water include biodegradable organics, suspended solids, plant nutrients, dissolved solids, and pathogens. The required treatment of wastewater depends on the highest use for the reclaimed water in the system. Usually reclaimed water is treated to meet unrestricted urban reuse, which requires the highestquality reclaimed water. For example, water for body-contact recreational use could require a high degree of removal of all constituents except dissolved solids. Orchard irrigation via surface furrows would require a lower degree of removal of many of the constituents but no intentional removal of nutrients or dissolved solids if wastewater is the source of supply. Certain industrial waterofdemands, as including water forconversion cooling towers, could require a very high degree of removal dissolvedsuch solids, of ammonia and phosphorus, and silica removal.

Basic Treatment Parameters Biodegradable organics. Biodegradable organics are often measured as biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC). Assuming a typical domestic wastewater, gravity sedimentation removes 30–40 percent of the BOD. Biological processes remove 85–90 percent of the BOD, producing water acceptable for landscape irrigation. Chemical coagulation and filtration removes more than 98 percent of the BOD, producing recreation water. Activated carbon removes virtually all BOD, producing water that may be suitable for groundwater injection. Suspended solids. Suspended solids are often measured as total or volatile suspended solids in all but very low concentrations (less than 5 mg/L). In the lower range, turbidity is used as an indication of solids concentration. The percentage removal of suspended solids from wastewater is approximately the same as with BOD. Plant nutrients. Plant nutrients include nitrogen (N), phosphorus (P), and sometimes potassium (K). These are often measured as ammonia-N, nitrate-N, and several forms

of phosphate-P and K ions. Removal of plant nutrients generally is not beneficial for irrigation uses, where the nutrients effectively replace commercial fertilizer. Removal might be beneficial for certain industrial uses where inhibition of biological growths or corrosion control is important. Nutrient-removal processes are usually specific to a given nutrient, such as P or N, or to the specific form of the nutrient. Examples would be nitrification to

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

ENGINEERING DESIGN — TREATMENT

53

convert ammonia-N to nitrate-N and denitrification to convert nitrate-N to nitrogen gas. There is a delicate balance between the need to remove nutrients, meet effluent requirements for wastewater discharge, and supply the major users of the reclaimed water with the most appropriate product. First and foremost, a utility must meet their discharge permit requirements. If the plant producing the reclaimed water cannot ensure 100 percent use of the reclaimed water through either direct use in the distribution system or through long-term storage, discharge permits will often require substantial removal of all nutrients. Dissolved solids. Dissolved solids usually include inorganic constituents, major anions, and cations. They are often measured indirectly as electrical conductivity, directly as dissolved solids by evaporation, or partially as specific ions. Removal of dissolved solids is beneficial to some extent for irrigation reuse and to a greater extent for various industrial uses. Dissolved-solids removal processes vary greatly, both by method and effectiveness. Some remove dissolved solids in general, as with reverse osmosis, while others remove only one constituent, with selective ion exchange. Pathogens. The presence of bacterial and viral pathogens and sometimes parasites is often measured indirectly by an indicator organism, such as coliform bacteria. The removal of pathogens is necessary for all classes of the use of reclaimed water. The degree of removal required depends on the specific reuse, including the extent of direct and indirect exposure of the general public to the reclaimed-water supply. Disinfection is usually accomplished with chlorine, although other methods, such as ultraviolet-light radiation and ozonation, are increasingly being used. In many systems, there is double barrier disinfection practiced using both UV and chlorine (for residual).

Reclamation Plants Centralized facilities. Reclaimed water can enter the nonpotable-water distribution system from (1) a centralized wastewater treatment plant that normally provides secondary treatment, disinfection, and discharge with a portion of the flow directed for nonpotable uses; (2) from a wastewater reclamation plant (centralized or decentralized) that provides secondary treatment as well as some advanced form of treatment such as filtration and disinfection (referred to as tertiary treatment; (3) a satellite facility that generally provides a high degree of treatment from a membrane or other treatment process. Satellite facilities. There are a variety of factors that drive the selection of a treatment strategy for either a conventional centralized facility or a satellite facility. They are •

The location of existing facilities;

•

Treatment objectives;

•

Site constraints; and,

•

Adaptability/flexibility of the selected treatment process to meet prescribed goals.

In turn, these characteristics determine the nature of the unit process technologies considered applicable for the respective applications. In this context, secondary treatment consists of screening and grit removal, sedimentation, and low-rate processes, such as stabilization ponds and aerated lagoons; or high-rate processes, such as activated sludge, trickling filters, or rotating biological contractors. A satellite reclamation facility is generally located close to the point of use and has a variety of attributes, such as •

•

A location within a well-developed area (being urban, industrial, or mixed) adjacent to a trunk sewer line or interceptor; Designed with a treatment capacity closely matched to the actual reclaimed water demand of nearby end-users; and,

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

54

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

•

Designed to be very compact (given availability and/or cost of land), and to have a minimal impact on the surrounding community (enclosed facilities, attractive finishes, noise abatement, odor control).

How does one determine whether a satellite facility is appropriate (as compared with a conventional facility), and how does one determine what unit operations are appropriate to achieve the expected levels of treatment for the reuse application? Recent technological developments, such as membrane bioreactor (MBR) technology, biological aerated filters (BAF), and integrated fixed-film activated sludge (IFAS), have been able to cost-effectively address the technical, economic, and implementation impact constraints associated with satellite facilities or additions to conventional plants. The advantage of using satellite reclamation plants is that they can be located in the area where reclaimed water isreclaimed needed. Figure shows such a plant located in can a residential area.the Excess flow, excess water,4-2 biosolids, and wastewater solids be returned to the trunk sewer to be handled at the central wastewater plant. The planning and design must ensure adequate flow in the collector and trunk sewers to flush the heavy solids levels to the central plant as well as ensure that the central plant is not overloaded with organic materials, which might result in a plant upset. Facility operation. Design aspects of reclamation plants include standby power supplies, standby or replacement equipment, treatment-process redundancy and reliability, enhanced disinfection, emergency storage and disposal provisions (including alarm systems), monitoring equipment, and automatic actuators (see Chapter 2 for suggested guidelines). Operation aspects include the development, documentation, and exercise of sound routine and contingency operating procedures, and a comprehensive preventive-maintenance program. All of these considerations help to ensure that only water of acceptable quality is delivered to the reclaimed-water distribution system.

Figure 4-2

Satellite reclamation plant in residential area (courtesy of Black & Veatch)

` , , ` ` ` , , , , ` ` ` ` ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

ENGINEERING DESIGN — TREATMEN T

55

Disposal of excess reclaimed water. When a nonpotable-water supply is fairly constant throughout the year, the excess may need to be discharged during periods of low demand. This can be accomplished in the same manner as traditional wastewater disposal. As expected, site-specific constraints and regulatory considerations may greatly inhibit available disposal options.

REFERENCES _______________________________________________ Okun, D.A. 1991. Reclaimed Water—An Urban Water Resource. Water Science Technology. 24(9):353. London, England: IWA. Florida Department of Environmental Protection. 1999. Reuse of Reclaimed Water and Land Application, Chapter 62-610, Florida Administrative Code. Tallahassee, Fla. ` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

USEPA. 2004. Guidelines for Water Reuse. Washington, D.C.: USEPA. Uniform Plumbing Code. 2003. Reclaimed Water Systems for Non-Residential Buildings, Appendix J. Ontario,

Calif.: International Association of Plumbing and Mechanical Officials.

This page intentionally blank.

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

AWWA MANUAL

Chapter

M24

5 Engineering Design — Distribution

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

This chapter details the engineering issues that should be considered for the design of the nonpotable portion of dual water distribution systems. These include design issues, pipe materials, storage, a nd distribution system components. In many ways, the design of a nonpotable-water distribution system is the same as for a potable-water system; that is, water quality and quantity parameters must be met with a high degree of reliability. The major differences in the design of a nonpotable-water system include demand management, the differences in the various design components and the end user.

DEMAND MANAGEMENT ___________________________________ Peak demand for reclaimed water in a distribution system can vary significantly depending on the amount of operation al storage and mode of operation (on-demand or controlled-demand). Potable-water usage usually is unrestricted (on-demand). For nonpotable systems, controls may be placed (controlled-demand) on such uses as i rrigation. Such controlled demand can reduce peaking and operational storage requirements and significantly i mpact the design of the nonpotabl e system. To control demand, strict scheduling of irr igation is sometimes implemented to minimize public contact and to conserve water by reducing evaporation. For instance, schools, parks, golf cou rses, and major g reenbelts might be required to irrigate between the hours of 9:00 p.m. and 7:00 a.m. Irv ine Ranch Water District (California ) is a n on-demand system but restricts landscape irrigation to n ighttime. They now require golf courses to have onsite storage to eliminate diurnal variations. San Antonio (Texas) restricts irrigation year round to an 8:00 p.m. to 10:00 a.m. w indow. From a practical standpoint, golf course irrigation must be complete by 6:00 a.m. to allow use of the course. Significantly high-peak demands can create difficulties in maintaining system pressure. One of the most effective means of compensating for significant peak demands is to vary the days of the week that each area is irrigated. The irrigation duty cycle (days on versus days off) also ca n be varied for seasonal ir rigation demand. This method of operation

57 Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

58

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

can reduce storage needs, allow for lower pressures, and elimi nate the need for ad justing the irrigation cycle during the year. The types of users on a system often have an impact on system design. For example, industrial users are typically one- or two-shift operations (although some facilities operate around the clock ) while residential and commercial users are usual ly daytime users. If the community is fortunate to have a balance between daytime users and nighttime irrigation users, this results in more economical pipe sizing and efficient system operation . Demand management and efficient system sizing can be facil itated by optimizing delivery schedules among th e various customers. This can ba lance the day-to-day and diurnal de mands, resulting in economic benefits in sizing system compone nts. Another effective means to control demand is to require on-site storage for large system users, allowing these large demands to be met by delivering reclaimed water over a 24-hour period, or when demands are low. The users can then use “their” water at high irrigation rates without negatively impacting the utility system (or creating the necessity for larger distribution system lines). A pond used for golf course or park irrigation is a typical example of on-site storag e that can be used as needed and filled on a steady basis.

SYSTEM HYDRAULIC MODELING _____________________________ To fully analyze the various distribution system options that may be available for a reclaimed water project, hydraulic mode ling of the di stribution system is undertaken. While it is recognized that each reclaimed-water proje ct wil l have unique project-related requirements, it is nevertheless helpful for a utility to develop standardized design criteria for reclaimed-water proj ects. Criteria should include : peak ing factors; storage requirements; pump station sizing; min imum and max imum delivered reclaimed-water pressure; minimum and maximum velocity of reclaimed water in the distribution system; estimated percentage, based on customer ty pe, of potable-water dema nd that ca n be replaced with reclaimed water; modeling period; and water delivery reliability. All of these criteria become a part of the process to model the reclaimed-water distribution system. A reuse distribution system is designed much the same as a community’s potable distribution system. A combination of elevated storage, ground storage, and booster pumping stations is used to mai ntain the system pressure if the system is designed to serve all customers from one central location. For example, Table 5-1 illustrates the potential reuse demands that must be met for the Raleigh, N.C. system that serves 90 square miles. There are several unique challenges in modeling the reuse distribution system, including very high peaking factors, wide-ranging pressure requirements, and perhaps, including the development of a large regional model.

Table 5-1 ` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Projected reuse demands for Raleigh, N.C., reclaimed-water system

FirstPhase

ADF

MDF

2,508,200

6,874,400

MHF 19,473,600

NortheastRaleigh

1,011,973

5,505,134

12,909,000

WestRaleigh

1,713,800

4,003,000

11,600,000

NorthwestRaleigh

112,500

350,000

1,106,000

Garner TotalUsage Note:

328,000

1,033,000

2,345,000

5,674,473

17,765,534

47,433,600

All values are mgd.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

ENGINEERING DESIGN — DISTRIBUT ION

59

The nature of reuse demands, particularly irrigation demands, requires the system to be very flexible in meeting high peak demands. Seasonal impacts on i rrigation demands can create daily peaki ng factors as much as three times the average daily demand. In addition, most golf course irrigation takes place overnight or during early morning hours, before the golfers begin play . If a ll courses i rrigate duri ng a four-hour period in the early morning, the hourly peaking factor could be as high as 20 times the average daily demand. By comparison, hourly peaking factors for potable-water distribution systems typically range from 3.0 to 3.5± times the average daily demand. The wide range of flows for the reuse system is accompanied by a wide range of pressure requirements. Many golf courses u se irr igation ponds to store water. These systems will discharge to atmosphere. However, other systems prefer to connect directly to the distribution piping and let the system pressure deliver flow to the irr igation systems. In these cases, mini mum pressures as high a s 50 psi may be required. The specific requirements of each individual u ser must be clearly understood to ensure that a system meets the customer’s needs. Typically, when modeling a system, the utility chooses a minimum pressure. Often, reclaimed water systems are designed to ensure pressures are maintained 5 to 10 psi lower than adjacent public water distribution systems. Users that would take reuse water to fill ground-level ponds from the syste m will be provided with pressure-sustaining valves to prevent them from depressu rizi ng the surrounding dist ribution system. Multiple utilities in a large area that is well-developed offer unique modeling challenges. The extent of the system may require phased construction over many years. The initial phases must economically distr ibute reuse wate r to the customers in the first phase and allow for economical expansion for future phases. The distance to some of the reuse sites may be great and may preclude construction of that portion of the system for many years. However, a comprehensive plan must allow for future connection to these sites. Therefore, the initia l transm ission network must consid er future demands, while incorporating future costs in determining the most effective phasing of the system.

DESIGN COMPONENTS _____________________________________ Judicious design for future growth is essential in any distribution system whether it be for potable or nonpotable water. There are a variety of considerations that might factor into the design a nd implementati on of a dual distribution system. For new communities, a new paradigm could be utili zed for the design of the dual distribution system. For existing systems, some of the major factors m ight include pumps and pressure zones, pipe material and size, metering a nd storage. In a new community, the drinking water distribution system could be designed to serve only potable purposes as previously described in Chapter 3. In this new design paradigm, pipe sizes would be very small and could use more durable materials. The reclaimed-water system would be designed to fire protection standards and would have larger pipe sizes. Drinking water distribution systems that produce fire flow are required to maintain a mini mum pressure while providing both the fire flow plus the peak hour demand for the neighborhood. Reclaimed-water fire-flow systems have to provide only the fire flow, which could result in optimized pipe sizes. Avoiding cross-connections would be easier because the two systems are so very different. Such a system has been operating successfully in Rouse Hill, a suburb of Sydney , Australia, serving a population of almost 100,000 for more than a decade. There are some institutional impediments for consideration of such reclaimed-water distribution systems that would allow reclaimed water to be used for fire flow. Presently, few agencies or states allow fi re flow with reclaimed water. While used in a variety of other locations throughou t the world, it will requi re some legislative or administrative changes to make it a possibility in the United States.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

60

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Pipes The hydraulic design of a reclaimed-water system is quite similar to that of a typical potable-water distribution system. Hydraulic calculations are developed utilizing any of a number of computerized systems. Knowledge of the location of major reclaimed-water users and their spatial location within the community are the primary criteria for des ign. Depending on the size of the system, ground and/or elevated storage may be necessary to balance flows and pressure while providing a reliable source of reclaimed-water supply. In many insta nces, increasing a pipe diameter one s ize can easily be justi fied because over half of the initial cost of installing the pipeline is for excavation, backfill, and pavement removal and replacement. The difference in cost from one size to another is primarily because of the material cost. In pumped systems, some of this cost can be recovered in reduced energy costs during the in itial years of operation. Color coding of potable and reclaimed-water piping is used to differentiate the pipes. Purple is the typical pipe color for reclaimed-water systems (see Figure 5-1). ` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Major Structures Major structures such as pump stations and storage facilities should be designed fo r easy expansion. Space should be provided for additional pumps and electrical equ ipment. Additional capacity frequently can be obtained through changes i n impeller and motor size, which leave the pump housing unchanged. Yard piping connections and valves should be considered at storage tank locations to facilitate future system additions.

Service Connections Future service connections that cannot be accommodated by simple taps should be installed at locations where expansion is likely. Installing small-diameter service connections for future users is rarely justified, because these taps ca n be made when needed and at a location that benefits the user and the water purveyor. A typical tap is illustrated in Figure 5 -2. It prominently states that reclaimed water is in use.

Figure 5-1

Purple pipes for reclaimed-water distribution system

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

ENGINEERING DESIGN — DISTRIBUT ION

Figure 5-2

61

Line tap into reclaimed-water line

Pressure Pressure requirements depend largely on the type of service provided through the nonpotable system. The m inimum pressure can be as low as 10 psi (68.94 kPa) if additional booster pumps are provided by the user at the point of delivery. Maximum pressure can be 100 to 150 psi (689.48 to 1,034.1 kPa), depending on users’ needs or piping material limitations. Some utilities maintain the nonpotable system pressure somewhat lower than the potable-water system pressure, which is presumed to reduce the risk of cross contamination.

Pipe Material Pipe material selection should be based on pressure and the anticipated quality of the nonpotable water. Pipe materia l, such as AWWA C900 St andard for Polyvinyl Chlor ide (PVC) Pressure Pipe and Fabricated F ittings, 4 In. Through 12 In. (100 mm Through 300 mm) for Water Distribution can be specified. Pressure class should be considered based on state requirements for separation distances, recognizing that 150 psi or 200 psi pressure pipe will be appropriate for water main crossings and restricted horizontal installation. Pipe for nonpotable water should be colored differently than pipe used for potable water, and purple is the accepted color. Tracer tapes should be used when laying the pipe so that the pipe may easily be located should repairs need to be made, and tracer tape is also always used for pipe other than plastic, which are not integrally colored. System appurtenances. Transm ission and distribution valves should be spaced using guidance from the utility that distributes potable water to match local practices. If loss of reclaimed water caused by future system expansion or tapping for a new customer would be considered an unauthorized di scharge by the regulatory authority, more valves should be included in the system to allow pressure isolation for connections. Many appurtenances such as air release valves, surge valves, altitude valves, flush valves, and other system components may not be available in the color purple, but they can be painted or otherwise appropriately marked. Aboveground appurtenances always should be pai nted or labeled to indicate they are i n service for reclaimed water. Buried componen ts can a lso

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

62

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

be painted, labeled, or wrapped appropriately with the visible surface valve covers painted and labeled to reflect a nonpotable use. Several manufacturers provide meters and other appurtenances with internal components selected for the higher anticipated TDS levels of reclaimed water. Figure 5- 3 illustrates a typical meter box labeled for reclaimed water , and Figure 5-4 illustrates typical valve box covers, which are distinctively different from the typical round box used for potable water. Blowoff and drain valves are especially necessary for irrigation tran smission and distribution systems in regions subject to seasonal irrigation demands and systems subject to freezing.

STORAGE _________________________________________________ Matching the nonpotable-wat er supply with demand is importa nt, particularly when waste water is the source of supply for nonpotable water. Wastewater flow is generally constant throughout the year, while nonpotable demand (typically irrigation demand) tends to be seasonal. Large volumes of daily and seasonal storage may be necessary if all available nonpotable water is to be used. The variance between the supply of reclaimed water and demand can be compensated in several ways, including the following: •

Store enough nonpotable water to balance supply and demand;

•

Supplement nonpotable water with another source to satisfy peak demands;

•

Dispose of excess nonpotable water;

•

A combination of the above.

The reliability required of a nonpotable-water system is usually not as great as that of a potable-water system. Households or industry usually cannot tolerate interruptions in potable-water service even for a few minutes. Nonpotable-water systems that supply irrigation water can be cut off for a day or two without undue harm. Most vegetation can withstand a period of time (depe nding on plant type) without watering. A determination should be made for individual systems a s to the acceptable length of interrupted service. User service agreements may include provisions relating to ser vice interruptions. Storage requirements can then be established. Where fire flows may be provided by the nonpotable system, storage should be sized for the local design fire flow . Reliability is essential if fi re flows are included in the nonpotable system. Design precautions similar to those in a potable system would be employed, including looped service lines and standby power. Because storage for fire-flow demands will typically result in greater storage volumes, tank turnover and maintenance of adequate disinfectant residuals in the nonpotab le system will be critical to ma intaini ng good water quality, not only for nonpotable uses but also for fire fighting. Sufficient storage must be designed into the system to handle any plant upsets. Upsets can be overcome by discharging the poor-quality effluent to the sewer or holding basin where water is drawn from operational storage. The di scarded effluent is then returned to the plant for retreatment when the plant is restored to proper operation. This is done automatically at some plants when turbidity li mits are exceeded.

Seasonal Storage In a nonpotable-water system using reclaimed water and having no alternative disposal methods available, the seasonal difference between the rate of treated wastewater production and reclaimed-water be buffered large storage reservoirs. Surplus effluent, produced dur ingdemand periodscan of low dema nd,by ca n be impounded for subsequent withdrawal during periods of high demand. A major advantage of seasonal storage is that it uses all available reclaimed water, maximizing water conservation. A large reclaimedwater system may require more tha n one seasonal storage reservoir .

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

ENGINEERING DESIGN — DISTRIBUT ION

Figure 5-3

Figure 5-4

63

Reclaimed-water meter box

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

Reclaimed-water valve box Surface impoundment, either open or covered, is another form of seasonal storage. This seasonal storage could be used to support downstream water rights during peak summer demand for reclaimed water from the production facility, provide for needed supplemental water du ring dry seasons, or long-term storage year over year.

Evaporation As with al l open storage reser voirs, significant evaporation ca n occur. The larger the reservoir surface area per unit of volume, the greater the evaporative loss. The loss should be calculated and used when determining reservoir size. Compensating inflows from direct precipitation or other sou rces might offset evaporat ive losses.

Open-storage Impacts on Water Quality A supply initially disinfected to the requirements of potable water very likely would be degraded at least to some extent in open storage. Open storage degrades water quality by increasing suspended solids through algal growths and uncontrolled surface inflows.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

64

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

The concentration of pathogens can be impacted by the reservoir configuration, uncontrolled inflow, and the level of disinfection achieved in the supply prior to storage. A recent Water Environment Research Foundation (WERF) study documents some of these environmental impacts on storage. If treated wastewater containing significant quantities of nutrients is impounded in an open reservoir, the water is subject to quality degradation. To protect against water quality degradation, a water-quality ma intenance program is needed. The program should include one or more of the following: •

•

•

•

Posttreatment facilities to screen or filter particulate matter accrued during open storage. The use of a microstrainer or filter will remove the suspended solids at the central reservoir sites and reduce any special maintenance of the local sprinkler systems. A chemical to control algal growth or other equipment to assist in preventing excessive algal growth. This can be an algicide or a light inhibitor, such as blue dye. A destratification system to maintain reservoir homogeneity and prevent the undesirable consequences of seasonal turnovers. Rechlorination to maintain a residual in the distribution system.

If nonpotable water is used to replenish recreational lakes or other impoundments where particulates and turbidity may be troublesome, sand filtration, cloth media disk filtration, or multimedia filtration might be more appropriate than microscreening. When sizing surface storage reservoirs, sufficient excess capacity must be provided to accommodate precipitation and runoff produced by critical storm conditions should local regulations prohibit discharge from the reservoirs.

Operational Storage In addition to seasonal storage, operati onal storage may be requi red to meet daily or tem-

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

porary fluctuations in demand. Emergency storage, such as that for fire flows, may also be required. The key factors in determining operational storage volume are the balance of treated wastewater flow rates, the pumping rate into the distribution system, and the system demand variations. Irrigation time restrictions can create high peak pumping if the daily demand must be delivered in 8 to 12 hours. Other factors to consider are •

•

Reliability of system and components; Storage volume based on locally determined hours of uninterruptible supply;

•

Interconnection of sources (potable or nonpotable);

•

Distribution system loops; and

•

Alternate water supply connections.

The site and size of the storage reservoir(s) will depend on the degree of fluctuation and the availability of any supplemental supplies. Smaller, covered operati onal reservoirs may be used to control supplies into the distribution system (Figures 5- 5 and 5- 6). In some instances, it may be more economical to provide storage at the point of use as opposed to the point of supply. Thisthese is especially true for large (>100delivery AFY, 32.5 123 ML/Y) irrigation users. Design for conditions should consider at MG/Y, the 24-hour average rate during the peak month.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

ENGINEERING DESIGN — DISTRIBUT ION

Figure 5-5

St. Petersburg, Fla., reclamation plant

Figure 5-6

Storage tank for reclaimed water

65

Supplemental Supply A reliable volume of reclaimed water can also be ensured with a supplemental supply source. For example, an untreated or treated potable supply could be an emergency supplement for a nonpotable-water system. Such a supplemental supply would have to be protected from cross-connections (discussed in another section of this chapter). If supplemental sources of water a re available in sufficient quantity and are reliable, it may be more economical to use these sources rather than to provide storage. Supplemental sources might include: •

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Reclaimed plant interconnections;

•

Alternate reclaimed-water source; Potable water;

•

Untreated surface water; and

•

Stormwater runoff.

•

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

66

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Supplemental sources may improve or degrade the reclaimed-water quality. A supplemental source with slightly deficient water quality cou ld be blended with t he pri mar y source to achieve a combined supply of acceptable water quality. This requires an adequate margin of quality between the primary source’s constituent levels and the maximum values allowed in the blend, which is determined by the most constraining reuse demand. Some cooling tower or industrial users could also choose to blend water at the point of use. To a lesser extent this blending consideration may have to be applied to the introduction of water from open storage back to the distribution system. When blending, care should be exercised so that users of cooling tower and industrial process water are advised of such water quality cha nges. For example, phosp hate levels in reclaimed water can influence the choice of and feed rate for cooling tower water. In instances when there is not sufficient reclaimed water to supply a stipulated reclaimed-water contract and no other source of water is available, potable water may be used as a supplemental source to a nonpotable system. Delivery of potable water to the nonpotable system should only be through an air gap at a storage tank or an approved reduced pressure principal device. If stormwater runoff is used to supplement the reclaimed-water system, specific state regulations in some states could consider the commingled overflow to be an unauthorized discharge into the receiving stream. T his would effectively prec lude the use of stormwater runoff.

SAFEGUARDS______________________________________________ Protection of public health is the most important consideration in the design of any dual water distribution system. The acceptance of nonpotable-water systems by both the public and regulatory agencies is contingent on safeguards in design and construction that address the following principal d istribution conce rns: •

Prevention of cross-connections;

•

Prevention of improper use of nonpotable water; and

•

Prevention of improper operation of the system.

There are a variety of methods to implement the safeguards. The following safeguards are not intended to be inclusive but rather to identify major concerns. Nor are the guidelines intended to be mandatory but to describe measures that users and regulatory agencies involved with dual water distribution systems have implemented. The safeguards can be adjusted to meet the specific requirements of the utility, user, and regulator.

Prevention of Cross-Connections Each distribution system must have a good cross-connection/backflow preventio n plan to ensure no contamination of the potable-water supply is possible. Therefore, minimizing the potential for cross-connections requires careful design. Nonpotab le and potable lines should be separated by a sufficient distance so that there is little likelihood of misidentifying pipelines (see the section on pipe separation in this chapter). Reduced-pressure-backflow assemblies (RPBA ) should be instal led on all on-site potable-wate r services a nd fire services. Potable makeup water for lakes, storage ponds, and reservoirs should be protected by backflow-prevention devices (including air gaps). These means should be approved by the local regulatory agency. Any potable water used for seal water for nonpotable-water pumps should also be protected. A utility should consider substituting reclaimed water for potable water for this use. There should be no permanent, hard connection(s) between a nonpotable- and a potable-water system. All such connections (usually for emergency backup) should have

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

ENGINEERING DESIGN — DISTRIBUT ION

67

an ai r gap or have a separation for installation of an RPBA at t he time the interconnection is needed. Once the interconnection is no longer needed, the RPBA must be removed and the pipe ends flanged. All RPBAs must be installed abovegrade in a location not subject to flooding. Some users request a backup connection to the potable-water system. This can be accommodated with a wye connection and 45° flange fitting. Both reclaimed and potable sides of t he w ye a re protected with double check and RPBA units, respectively. If a switch to potable is desired, isolation va lves are closed and utilit y staff ca n remove a blind flange on the potable side, turn the 45° fitting, and reconnect the potable side. This allows ease of conversion without a continuous direct connection. Figure 5 -7 illustrates a backflow-prevention device. Some utilities have found it effective to minimize cross contamination between potable and nonpotable systems by operating the nonpotable system at a somewhat lower pressure (10 psi [68.94 kPa]) within the sa me service area.

Prevention of Improper Use

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

There are a variety of means to control public exposure to reclaimed water. Such methods can include everything f rom setback guidelines ( Chapter 2) to warning signs (in appropriate languages) to make sure the public is aware of reclaimed-water use. There are other very specific steps that can be taken to assure proper identification and use of reclaimed water, including identification systems, piping systems, pipe separation, and pipeline identi fication. Proper, consistent identification of the nonpotable-water system (including pumps, pipelines, reservoirs, and outlets) is the most effective method of ensuring proper use and the min imizi ng cross-connections. Identificati on is recommended so that nonpotab lewater pipes can always be differentiated from potable-water pipes. Figures 5-8 and 5-9 illustrate such signage. Signs can be worded to convey the appropriate warning and highlight t he user’s efforts at water conservation a nd environmental awareness. System components. A unique pipe color or material in combination with markings is the most effective method of identification. Various agencies have established color codes. For pipe carrying reclaimed-water, a purple or lavender color (Pantone 520 series)

Figure 5-7 Backflow-prevention device between reclaimed water and alternative source of nonpotable water

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

68

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

has been adopted (see Figure 5-1). Utility reclaimed-water systems should seek to coordinate their local regulations with those responsible for plumbing inspections. For example, the Uniform Plumbing Code (UPC), Appendix J, addresses “Reclaimed Water Systems for Non-Residential Buildings.” Although this Appendix specifically applies to reclaimedwater use in nonresidential (commercial/i ndustrial) buildi ngs, some have extended its use to irrigation systems on a property that i s otherwise required to obtain a plumbing permit for construction . The UPC i s explicit in the wrapping tape material, si ze, and wording. The UPC does not require w rapping tape for buried PVC pipe manufactured with purple color integral to the plastic and marked on opposite sides to read “CAUTION: RECLAIMED WATER. DO NOT DRINK” in intervals not to exceed 5 ft (1.5 m). Because commercially produced PVC fittings are not available in purple color, reclai med-water systems using pipe with the pur ple color integral to the pla stic should not be required to paint or wrap only the fittings. The connection of the fitting to purple pipe is sufficient to distinguish the pipe system a s a reclai med-water system. Outlets must be labeled and fittings should be designed so t hat interconnectio ns cannot be made between potable and nonpotable systems. Many state standards require the outlets be located in below grade locked boxes. Consideration should be given to operation of aboveground hose bibbs with a special operating wrench. If a hose is needed for irrigation or washdown, the connection should only be made using a quick-coupler. The hose connection should be a coupling-type, rather than threaded. Fire hydrants on nonpotable systems should be painted a un ique color and marked uniquely and should be t he type that has a g uarded operating stem and requires a special operating wrench.

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Figure 5-8

Neighborhood sign noting use of reclaimed water

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

ENGINEERING DESIGN — DISTRIBUT ION

Figure 5-9

69

Notice of use of reclaimed water by facility Pipeline identification. Identification can be embossed or stenciled on the pipe. More frequently, marking tape (with or without tracer material) or adhesive-backed, vinyl marking tape is used. Removable-type or slip-on-type markers are not recommended. Marking and labeling may need to be in languages other than English, depending on the locale. Pipe can be stenciled with “CAUTION: NONPOTABLE WATER” or “CAUTION: RECLAIMED WATER—DO NOT DRINK” at no more than 5-ft (1.5-m) intervals. Warning tapes with the sa me wording should be continuous along the entire pipeline, laterals, and fittings and should be taped to the pipeline at intervals not exceeding 10 ft (3 m). Plain, metallic plastic, or vinyl adhesive marking tape can be installed directly on the pipe longitudinally. The tape should be at least as wide as the pipe diameter, however, not greater than 3 to 6 in. (76 to 152 mm) in width. The tape is available in many different colors. The basic color should be chosen by the agency and used throughout its jurisdiction (see preceding section on pipe color). The tape should be installed along the top of the pipe for diameters 2.5 to 3 in. (63 to 76 mm); along both sides of the top of the pipe for sizes 6 through 16 in. (152 through 406 mm) in diameter; and along both sides of the top of the pipe and along the top of the pipe for sizes 20 in. (508 mm) and larger in diameter. Longitudinal polyethylene pipe wrap, purple in color in 4-8 mil thickness can be used to designate reclaimed water and simultaneously provide corrosion protection for steel and ductile iron pipe. Pipe separation. A reclaimed-water line in the vicinity of a potable-water line is treated like a sewer; a reclaimed-water line in the vicinity of a sewer is generally treated like a potable-water line. Figure 5 -10 illustrates the separation sta ndard for the installation of reclaimed-water lines in Washington State. As a practice, a 10-ft (3-m) lateral separation pipe wall to pipe wall should be maintained between the nonpotable line and parallel water or sewer pipelines. A vertical separation of at least 1 ft (254 mm) should be maintained between the nonpotable-water line and a crossing water or sewer line. In some locations this may be 18 in. (0.5 m) or 24 in. (1 m), with the top of the reclaimed-water line below the bottom of the potable-wate r line. W here new 150-psi nonpotab le-water mains a re instal led paral lel to existing potable -water and sewer mains that are separated by the nominal 10 ft, consideration should be given to locating the reclaimed-water main between the two existing utilities with the reclaimed main preferably below the potable-water line and above the

sewer in vertical Pipeline on nonpotable-water lines should be evenly spacedline on each side ofprofile. a crossing waterjoints or sewer line. Generally, states require a mi nimum 3-ft horizontal separation, pipe wall to pipe wall, but a 5-ft separation is most desirable. Where desired horizontal separation is not possible, use of a minimum 150-psi pressure pipe for the two utility mains can be considered placing the highest quality liquid vertically

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

70

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Typical Pipe Bedding Zone

Potable Water Line 1.5’ Reclaimed Water Line 1.5’ 1.5’ 10’

Figure 5-10

Sewer Line

10’

Typical urban utility pipe separations (Adapted from Washington State Water Reuse Group)

above the other. Table 5-2 illustrates the standards in a variety of other states. An excellent example of guidance for additional approaches to these situations is available from Washington State Departments of Health and Ecology.

Prevention of Improper Operation There are a variety of means to ensure that reclaimed-water systems are not confused with potable-water systems. Such meth ods range from the ty pe of appurtenances that are selected to the methods of control of irrigation water and system monitoring. Valve boxes. Valve-box covers for isolation valves, electrical control valves, pressure-reducing valves, pressure-regulation valves, and simila r appurtenances for reclaimed water should be specified as purple in color or painted purple. Valve-box covers should be designed so as not to be interchangeable with valve-box covers for potable-water lines. Figure 5- 4 illustrates such a distingu ishing valve-box cover . In Denver, a purple triangu lar lid is used. A bronze tag or other suitable item should be attached to the underside of the cover to identify the va lve type, size, number of tur ns, and di rection to open. Reclaimedwater distribution system valves are often specified to open opposite to the d irection potable-water valves open. Blowoffs and drain valves. Blowoffs or end-of-line drain valves should be painted purple consistent with other reclaimed- or nonpotable-water lines a nd appropriately labeled. Local regulatory agencies should be consulted relative to the location and operation of these valves. Special permits may be required. A utility may desire to route the discharge to a sa nitary sewer manhole to avoid any discharge permit v iolation should a state not permit the open discharge of reclaimed water to the environment. Irrigation controllers. Irrigation controllers should be labeled inside and out, warning that the system is using nonpotable or reclaimed water. The labels should also alert the owner or operator of the system of major operational constraints in the system. A reduced drawing of the a rea ser ved by the controller should be placed in a waterproof envelope in the controller cabinet. It should be updated as system changes are made. Storage facilities. All storage facilities should be identified by signs and labeled with the words “CAUTION: RECLAIMED WATER” or “DO NOT DRINK—UNSAFE WATER” or similar wording. Landscape irrigation. Landscape irrigation should be limited to those periods when public contact with the spray is minimal, usually at night, which will also reduce evaporative loss. The application rate and the duration of application should be based on the soil types a nd crop needs in the irrigated area. Tight clay soils should be irrigated at low rates and for short but more frequent periods to lessen runoff. In some areas, the

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

ENGINEERING DESIGN — DISTRIBUT ION

Table 5-2

71

Utility separation regulations and standards from various states

State

Drinking Water–Sanitary Sewer

Utah

10 ft horizontal

Massachusetts

10 fthorizontal

Oklahoma

10 ft horizontal

California

Georgia

Drinking Water– Reclaimed Reclaimed Water–Sanitary Water Sewer 10 ft horizontal

Source of Standard

Notes

10 ft horizontal or 3 ft horizontal

Utah Administrative Code

If reclaimed water is below or above sewer

Notaddressed

2001Guidelines and Policies for Public Water Systems

Reclaimed water not specifically addressed

Not addressed

Oklahoma Regulations for Public Water Systems; Water Pollution Control Facility Construction

Sewer and water line cannot occupy same trench

10 ft horizontal & 1 ft vertical

Reference to Reference to California Safe Cal-Nevada Cal-Nevada Drinking WaAWWA GuideAWWA Guideter Act lines for Dislines for Distribution of tribution of Nonpotable Nonpotable Water Water

If unable to meet separation; separation as far as possible in separate trenches

10 ft horizontal Not in same trench as sewer

3 ft outside to outside of pipe, 18 in. from bottom

Maximum obtainable separation possible;

5 ft horizontal

3 ft outside to outside of pipe

of water and top of reuse

Not specifically addressed

Not specifically addressed

Georgia Guidelines for Water Reclamation and Urban Water Reuse & Minimum Standards for Public Water Systems

water-sewer separations less than 10 ft – case-by-case review

Texas Administrative Code, Title 30, Part 1, Chapter 290.44

Parallel installations require separate trenches

Texas

9ftoutsideto outside in all directions

Texas Special Conditions

Nonpressure sewers: PE determination of no leaks; water 2 ft above, minimum 4 ft horizontal. New water line:minimum 150-psi pressure rated pipe; water 2 ft above, minimum 4 ft horizontal. Crossings:water 2 ft above sewer; if sewer leaking – replace 9 ft either side of water (18 ft total) with 150-psi rated pipe; new water line installation above sewer – segment centered over sewer 9 ft to joint both directions; new water over existing nonpressure sewer – water centered over sewer, sewer to have minimum pipe stiffness of 150 psi at 5% deflection,

sewer embedded in cement stabilized sand (2½ bags cement per cubic yard of mixture) 6 in. above and 4 in. below sewer.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

72

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

application should be controlled by soil-moisture probes and evapotranspiration rates. Frequent maintenance and inspection of the i rrigation system is recommended to correct broken or malfunctioning sprinklers. Most major sprinkler manufacturers have purple snap-in clips to designate the sprinkler head as a reclaimed-water fixture for retrofit of facilities. As spri nkler systems or heads a re replaced, new purple color spra y heads should be installed. Monitoring stations. Stations to monitor pressure, and to draw a water sample to take back to the lab for testing for chlorine residual and other water-qualit y parameters should be installed at key locations in the reclaimed-water distribution system. Rechlorination facilities should be considered at intermediate storage and booster pump stations to maintain desired chlorine residuals. Pressu re can be monitored on an instantaneous basis by a pressure gauge equipped with a threaded-hose connection or by a recorder. A recorder is particularly useful in performing pressure surveys for system analysis. Periodic sampling and analysis of the distributed water quality, both potable and nonpotable, is recommended and often required by regulations. Insufficient chlorine in the nonpotable or reclaimed system could stimulate a regrowth of bacteria. This scenario could cause odor problems in the distributed water, particularly where flow reversals move water from low-velocity or dead-end mains to high-use areas. Parks and playgrounds. Facilities and equipment found in parks and playgrounds (such as picnic tables, swing sets, and other outdoor recreational equipment, as well as outdoor drinking fountains) should be protected from overspray of nonpotable irrigation water through careful sprinkler layout and design. Drinking fountains should have protectiv e shields. Where new designs are considered, drinki ng fountains should be included in the interior of park and golf course comfort stations. Food establishments. Nonpotable water should not be used in food establishments, except where permitted by law for toilet flushing. Irrigation systems using nonpotable water should not be installed in close proximity to food establishments. ` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

REFERENCES _______________________________________________ Asset Planning (Treatment) Section of Asset Management, Rouse Hill Recycled Water Plant. 2005. Risk Assessment for the Production and Use of Recycled Water from Rouse Hill, R ecycl ed Water Plant . Internal

Report. New South W ales, Australia . AWWA. 2007. C900 -07 Standard for Polyvinyl Chloride (PVC) Pressure Pipe an d Fabr icated Fittings, 4 In. Through 12 In. (100 mm Through 300 mm), for Water Distribution .

Denver, Colo.: American Water Works Association. Florida Department of Environmental Protection. 1999. Reuse of Recl aimed Water and Land Application . Chapter 62-610, Florida Administrative Code. Tallahassee, Fla.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Okun, D.A. 1991. Reclaimed Water—An Urban Water Resource. Water Science Technology. 24(9):353. London, England: IWA. USEPA. 2004. Guidelines for Water Reuse. Washington, D.C.: USEPA. Uniform Plumbing Code. 2003. Recl aimed Water Systems for Non-Residential Buildings. Appendix J. Ontario,

Calif.: International Association of Plumbing and Mechanical Officials. Water Environment Research Foundation. 2003. Impact of Surface Storage on Reclaimed Water: Seasonal and Long Term. Washington, D.C.: WERF.

AWWA MANUAL

Chapter

M24

6 Management

INTRODUCTION ____________________________________________ Other chapters in this manual discuss the technical issues associated with nonpotablewater systems, including planning, engineering, and financing new systems. This chapter addresses managing those systems. Management of a dual distribution system is discussed from the perspective of an purveyor that retails water to multiple consumers like a potablewater system. Nonpotable-water system managers are water purveyors. However, unlike with potable water, nonpotable-water purveyors do not have a “natural” customer base with inherent demand for the product and services that nonpotable-water purveyors provide. As a result, managers of nonpotable-water systems must be more attentive to running their systems as businesses. In addition, nonpotable-water system managers typically must produce a range of products and services, establish and maintain demand for those products and services, and establish and sustain a positive image. Management issues associated with developing a new nonpotable-water system is a critical, but short-lived, management responsibility. Most management activities take place between initial development and subsequent upgrades of the infrastructure. This chapter provides guidance on these issues. Table 6-1 highlights attributes of different nonpotable-water systems and the management issues facing nonpotable-water system managers. Typically, an objective for reclaimed-water systems is to develop and sustain a high demand for nonpotable water as a means to decrease demand for potable-water resources.

MANAGEMENT PHILOSOPHY _______________________________ Development and management of an urban nonpotable-water system presents many challenges for the purveyors. In many instances the management of a nonpotable-water system is more demanding than that of a potable-water system. Identifying the type(s) of use that will be permissible from a regulatory standpoint and a utility prospective requires considerable analysis. Another concern that must be addressed is the issue of public acceptance of a nonpotable-water system. Public acceptance is of paramount importance if the program is to succeed. The public recognizes the need and benefits of a potable-water system.

73 --`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

74 PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Table 6-1

Attributes and management requirements for typical reclaimed-water applications

Typical Relative Demand

Type of Use Residential Irrigation In-home

Typical Variation in Demand

Typical Quality Requirements

Typical User Education Requirements

Typical Infrastructure Requirements

Typical Management Requirements

High MediumLow

Seasonal Low

High High

High High

High High

High High

MediumLow MediumLow

Seasonal

Low

Low

Low

Low

Seasonal

High

High

High

High

HighMedium

Constant

High

High

High

High

Municipal Irrigation, controlled access Irrigation, public access Industrial

However, they do not necessarily see the benefit of a nonpotable-water system. Consumer confidence poses the greatest hurdle to overcome because of the nature of most nonpotablewater systems. To manage a dual water system successfully, management objectives must be clearly defined. These objectives will vary, depending on the types of reclaimed-water customers, the types of reclaimed-water uses, public attitudes towards nonpotable-water use and other factors. Development of a dual system begins with identifying the type(s) of use that will be pursued and the type of customer(s) that will comprise the system. As part of the development phase, the purveyor must implement an outreach program to develop consumer confidence. Public opinion and attitude towards the nonpotable-water system will dictate the level of success of the nonpotable-water program. The unique challenges of purveying nonpotable water make management objectives and priorities situation-specific. Typical management objectives for nonpotable-water systems are listed and described in the following sections: •

Protecting public health;

•

System policies and procedures;

•

Developing the nonpotable infrastructure;

•

Understanding customer needs and requirements;

•

Establishing a viable customer base;

•

Service connections; and

•

System operations and maintenance.

PROTECTING PUBLIC HEALTH ________________________________ Protecting public health is the highest priority for the purveyor. The long record of successful applications of water reuse, both in the United States and throughout the world, demonstrates that water reuse can be practiced in ways that effectively protect public health. Despite the long record of success with water reuse, the management purveyor must be diligent in its attention to protecting public health.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

MANAGEMENT

75

Various entities have established guidelines for water reuse. Chapter 2 discu sses regulatory requirements that various states have established for using reclaimed water. Currently, there are USEPA guidelines, but no federal regulations associated with water reuse, although such regulations are likely to be developed in the future. (See Chapter 2 for a more detailed discussion of regulations.) Internationally, the World Health Organization (WHO) has published guidelines for water reuse that are generally less restrictive than the state guidelines. Several countries, some of which have been practicing water reuse for decades, have adopted guidelines for water reuse based on the WHO g uidelines. Even though clear-cut guidelines are lacking, the permitted purveyor must have a well-documented plan for managing the system to protect public health. Procedures for managing a dual distr ibution system must be established we ll before the system is placed in operation. The procedures can be modified later as experience is gained in operating the system. Key elements of the management plan should include •

Product quality control

•

System integrity control

•

Compliance and enforcement

•

Staff training

•

Public education

Product Quality Control Prudent water-quality standards should be based on the intended uses of the water and the management program the user intends to implement. Standards for reclaimed water will most likely be prescribed by the state. In many instances, the intended uses of nonpotable water may be broad. The purveyor must evaluate the required water quality for each type of use to determine which practical applications will be accepted. This decision will most likely be based on regulatory requirements, treatment requirements, and budgetary impacts. In addition, the purveyor should develop a strategy (QA/QC sampling) to ensure the system meets and maintains all applicable standards.

System Integrity Control Procedures should be established to ensure the integrity of the dual distribution system. The nonpotable system should be color-coded and labeled to prevent accidental crossconnection between potable water and nonpotable water by the property owners, contractors, irrigation system installers, and plumbers. Adding specific wording and international symbols for nonpotable-water systems also improves the safety level of the dual distribution system. Leak detection programs, cross-connection control, and backflow prevention are also important components of ensuring a safe system. The guidelines in Chapter 4 can be referenced to avoid cross-connections.

Compliance and Enforcement An appropriate regional purveyor is responsible for ensuring that the purveyor and the customers are in compliance with all state and local regulations at all times. The purveyor, if delegated, may assume the responsibility for ensuring that the customers are in full compliance. Enforcement procedures must be developed to handle issues when they arise. Compliance should be detailed in local codes as well as in the policies and procedures manual that governs the nonpotable program. The field inspector should have adequate authority to take action to ensure continued compliance. In case of a minor infraction, the inspector may elect to notify the customer of his findings and grant a grace period to

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

76

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

correct the violation without interrupting service. If the violation poses a potential health hazard, the inspector must have the authority to cite the customer for the violation and/or to discontinue service to the site until compliance has been reinstated.

Staff Training All staff members involved in the operation and maintenance of the dual distribution system should be properly trained. This training must focus on regulatory and local policies as well as cross-connection control, site inspection, treatment, and water quality issues. These training programs should begin prior to the operating process. Some states have developed certification programs that provide training for field operation staff as well as management and production personnel so that everyone involved understands the requirements to ensure the dual is operated in a safe andmanager equitableismanner. At a minimum,that training anddistribution certificationsystem as a water system distribution recommended for dual distribution systems operations personnel.

Public Education Public education is essential in protecting public health during the construction and use of dual distribution systems and is a critical component for the success of any reuse program. To promote water reuse a community should adopt an aggressive education program that includes tips on both water conservation and water reuse. Such a program might include a reuse brochure and information on the community Web site. The community might also consider developing a community gathering that focuses on water and water reuse. One such example is the Raleigh, N.C., WaterFest held annually to educate the public on all facets of water reuse (Raleigh, N.C. 2007). The brochure can be distributed with demand surveys that would be mailed to prospective customers. They can also be used as direct mail pieces or as bill inserts, or located at each of the reclaimed-water facilities. Programs at local schools are also an excellent way to promote the use of reclaimed water. New customers applying for reuse service should clearly understand the composition of the water they will be receiving for their nonpotable needs. The information can be presented in several ways beginning with an orientation session, review of policies that govern the program, and informational writeups and other literature generated by the purveyor to promote reuse. The information should not be technical in nature, but it should clearly explain the permitted uses and those uses that are not permitted. The information should be concise and in short paragraphs to help maintain the customer focus and interest during this orientation period. Audio/video and other equipment can be used to help the audience understand the details of health and safety issues as well as the treatment process used at the water reclamation facilities. Users should also be encouraged to view and treat reclaimed water in the same manner as all other nonpotable-water supplies, such as irrigation water. The use of video technology provides the purveyor with a consistent format for the viewer. Redundancy in delivery is encouraged to reduce the potential for miscommunication and misunderstanding. A period for questions and answers should be provided after the audio/video presentation. Other positive reinforcement, such as color-coding and signage explaining that nonpotable water is being used for irrigation or other purposes on the property, is encouraged. Operational procedures such as color-coding, service tap installations, user requirements, as well as the inspection process and why it is necessary should be ex` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

plained. Thebenefits need to of minimize inadvertent contact with the community water by individuals visiting the site and the the nonpotable-water system to the should also be made clear to the audience.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

MANAGEMENT

77

SYSTEM POLICIES AND PROCEDURES _________________________ Typically, management activities occur in the initial development of the nonpotable-water system and during upgrades to the system’s infrastructure. The formation of a policies and procedures manual should occur during the initial development of the nonpotable-water infrastructure. The policies and procedures manual serves as a guidance document and must be developed after determination of a well-defined program for the dual system. This document will assist in developing and maintaining customer confidence for the nonpotable-water system. Development of the nonpotable-water infrastructure identifies the key elements necessary for initial development as well as during subsequent upgrades or modifications to the system.

Policies and Procedures Manual Once the primary program for the dual system has been targeted, it is crucial to begin developing a policies and procedures manual for the orderly development and management of the system. This document will initially govern the program during the start-up process and provide an important operations tool over the life of the system. The policies and procedures manual should be created well in advance of the system being placed into operation. It will also be of assistance during the promotional phase of the program to build consumer confidence. As the program begins to develop, periodic updates and revisions will be necessary to ensure compliance with federal, state, and local regulations. Currently, most people in the United States take potable-water service for granted; however, nonpotable-water products and concepts must be marketed to the consumer as a safe and reliable water source that will meet their nonpotable needs and present no health risks to the user and the general public. This should be accomplished through regulatory oversight and well-defined operational policies and procedural protocols.

Managing Nonpotable Uses Nonpotable water may serve a variety of uses in an urban water-service area. These may range from residential to industrial use and public-use land holdings. The management of the reclaimed-water use may differ for each class of user.

Residential Uses Indoor residential use. The use of reclaimed water in the residential setting is generally limited to landscape irrigation and, in a few instances, to toilet flushing. While crossconnections in the residential setting are of significant concern, the use of dual distribution systems in single-family residences is gaining some acceptance and the potential for the cross-connections would most likely be in the interior plumbing for toilets. Adequate safeguards should be in place to ensure that “do-it-yourselfers” do not make connections to the wrong supply. Such uses in a condominium, apartment, or high-rise residential building is of less concern because only licensed plumbers would have access to the plumbing system. Outdoor residential use. Outdoor residential reclaimed-water use is generally for irrigation purposes. All hose bibbs and other connections to the reclaimed-water system should be properly marked to indicate that they convey reclaimed water. As with interior uses previously noted, adequate training of the homeowner with respect to the use of the reclaimed-water system is key to avoiding long-term issues. Public education plays a significant part in ensuring that the homeowner will treat the reclaimed-water system appropriately. New customer education, as well as repeated reminders through bill stuffers and public education campaigns is an effective public education initiative.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

78

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Commercial Uses Buildings. Commercial and public office buildings offer opportunities fo r nonpotable-water u ses, such as air conditioning and toilet and urinal flushi ng, a nd may constitute 80 to 90 percent of the total water usage for large commercial centers. Where reclaimed water is utilized for toilet flushing, local ordinances may prescribe marking those toilets that are associated with reclaimed water. This should be a consideration in every design. In addition, among a number of cities, San Francisco has adopted a code requiri ng separate plumbing for toilet fl ushing when reclaimed water is avail able. Landscape irrigation. The other large commercial use, particularly in the office and campus setting, is for landscape irrigation. The advent of green roofs for commercial (and public) buildings has provided another demand for the use of reclaimed water in newer commercial construction. Frequently, many of these campus areas will include impoundments for decorative purposes. All of these landscaping applications should be properly marked to indicate that reclaimed water is being used. Construction. Principal uses for reclaimed water in the construction industry include use in the manufacture of concrete, watering gravel roads and haul roads for dust control and cleanup, increasing the moisture content of earthwork to improve compaction, curing concrete, and washing down at construction sites. In each of these uses, local or state regulations may require adequate marking and other such strategies to ensure that the users of this reclaimed water fully understand its source and level of treatment.

Municipal Uses

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

While reclaimed water is the “new” water resource and has a variety of uses as described in the following sections, conservation of both potable and nonpotable water should be the hallmark of any program. For example, reclaimed-water use in landscaping can be reduced by xeriscaping (using native plants). Landscape irrigation. By far the largest urban use of nonpotable water is for landscape irrigation. The places for its use include cemeteries, parks, playgrounds, school yards, street and freeway medians, nurseries, tree farms, golf courses, and building grounds. The quality of the water required for these uses will vary, as noted in Chapter 2. Frequently, many of these areas include impoundments, either for storage or decorative purposes, that help to balance flow demands and impact distribution system design. All such locations should post that the irrigation water is from a reclaimed-water supply. Lakes and impoundments. When reclaimed water is used for lake makeup, preventing algal growth is nearly impossible, even if the nutrients are mostly (but not completely) removed from the wastewater. After a period of time, nutrients arrive by wind-blown dust and debris and incident precipitation, thus further promoting algal growth. Problems can be minimized by maintaining good circulation, avoiding shallow bays, maximizing side depth and slope (within local regulations), diverting runoff from adjacent areas, and minimizing detention times to no more than 7 to 10 days. Artificial aeration is sometimes beneficial, and the lake perimeter should be kept free of nuisance growth. (WERF, Black & Veatch 2004). All such impoundments and lakes should be adequately marked to indicate that they contain reclaimed water.

Industrial Uses Industrial uses generally include cooling-water makeup and process rinse and washwater. These uses generally vary by industry type. Cooling-water makeup. Cooling water is one of the largest water uses at the typical industrial facility and generally requires a reasonably high-quality water so as not to foul the cooling towers. Certain constituents in reclaimed water decrease the number of cycles of concentration and increase corrosion and chemical costs. For example, dissolved

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

MANAGEMENT

79

organics and nutrients in reclaimed water can increase the demand for biocides to control algal growth. Calcium, phosphorus, silica, and other minerals form precipitates when concentrated and can also limit the cycles of concentration. Ammonia reduces the effectiveness of copper and brass heat-exchange surfaces. To assess these potential impacts, a detailed constituent-by-constituent comparison between the potable water available to an industry and the quality of the proposed reclaimed water should be prepared. If the industrial user is of sufficient size, they should be consulted to ascertain if additional treatment to remove particularly troublesome constituents would be cost-effective for both parties. Process use and wash water. Large quantities of water are used in the manufacture of paper products, metal finishing and plating, fume and stack scrubbing, and paint spray booths, among others. If a significant use is identified, there should be discussions with the industry regarding the required water-quality characteristics and quantities needed. Proper control of the reclaimed-water use within the process is important. Generally, this is not a problem in the industrial setting, because each industry has their own method of marking the various inputs to the industrial process. The municipality must work with the industry to assure that an adequate cross-connection program is in place.

Other Uses Agricultural uses. In many urban areas, crops are being raised that can be irrigated with reclaimed water. The regulations regarding the use of reclaimed water for such irrigation purposes are almost exclusively the purview of the state where water is used. Sometimes, local rules may be even more constraining. Aquaculture uses. The use of reclaimed water to supplement freshwater sources is increasing. Large fish farms will often treat their wastewater and then recycle it into the fish ponds. Additional reclaimed water from local municipal supplies may also be utilized to supplement the makeup water for the ponds. The regulations regarding the use of reclaimed water for such irrigation purposes are usually the responsibility of the state. Groundwater recharge. As water supplies are becoming stressed from ever increasing population growth and climate change, groundwater recharge with reclaimed water is becoming increasingly common. There are a variety of methods for accomplishing this. Aquifer recharge programs, like the “Aquifer Replenishment Program” in Orange County, Calif., inject reclaimed water into an aquifer to displace brackish water. Aquifer storage recovery systems require an engineered design and permitting.

DEVELOPING THE NONPOTABLE INFRASTRUCTURE _____________ Management responsibilities for developing the reclaimed-water infrastructure are needed for the development and modification of the nonpotable system. As with a potable-water system, a nonpotable-water system should be developed responsibly to meet demand without incurring unreasonable cost in speculation of potential demand. The key elements to developing the nonpotable-water infrastructure include •

Plan checking

•

Field site inspection

•

Record drawings

•

Customer site documentation

Plan Checking As with the initial installation, a professional engineer should design any modification to nonpotable- or reclaimed-water facilities and prepare plans and construction specifications.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

80

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

To ensure consistency in the design of a nonpotable-water distribution system, the purveyor should consider the development of standard specifications and details that relate to the means, methods, and materials of construction for the system. Elements of the nonpotable-water distribution system that may be addressed with standard specification and details include •

Pipeline identification, testing, and placement

•

Public notification of reclaimed-water use

•

Valve boxes and covers

•

Meter and meter boxes

•

Backflow-prevention assemblies

•

Cross-connection control

•

Hose bibbs

•

Irrigation system controls

•

Holding pumps

•

Runoff control

The design engineer should meet with the nonpotable-water distributing purveyor before the start of design to identify specific project design requirements, minimum line sizes, and points of connection. The engineer should provide proof of diligent search of utilities and substructures by providing letters of approval from all known utility companies to the water purveyor. Where there is any question of separation, exploratory substructure excavations should be required to determine actual elevations of existing potable-water and sewer lines. The design of the system should be reviewed and approved by the appropriate state or local regulatory agency prior to the start of construction. The plan review should be in sufficient detail to ensure identification and separation. The location of blowoffs and drain lines should be coordinated with the regulatory agencies to verify that discharge is only to approved locations. The designer should review existing project record drawings of customer sites and discuss all desired modifications with the site owner or representative. The location of all utilities and potable-water lines and connections should be verified. During the plan check, all connections to potable-water lines should be identified and clearly indicated to be severed and capped, and backflow-prevention devices installed on potable-water lines and fire-protection water lines. Plans should clearly show the location of all warning signs.

Site Inspection The inspection of facilities is critical for the safe operation of a dual water distribution system. The potential for cross-contamination is particularly acute in older systems, and extra diligence in inspection is required. Any connection to an existing system that results in conversion from potable to nonpotable water requires close scrutiny and must be approved or witnessed by the nonpotable-water purveyor and the owner or representative of the existing system to ensure that no inter-ties occur between the nonpotable system and the potable-water system. Multilevel site inspections consisting of a minimum of two inspection trips should be conducted before a user site is connected to the nonpotable-water system. The first site visit by the purveyor presents an opportunity to develop a profile of the user site. The information captured during this visit will be maintained in the customer’s file as historical information. It is important during this time to determine what modification(s), if any, will

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

MANAGEMENT

81

be required to bring the site into compliance with state and local regulations. The inspector’s notes will incorporate any deficiencies and abnormalities that need to be corrected by the customer or their designee. The findings of the inspector should be documented in the purveyor’s files and copied to the customer for their files. If corrective actions are necessary, this document should provide a detailed list of what deficiencies exist and what actions are required. A second inspection should be conducted to confirm that any preexisting deficiencies have been properly corrected and no new conditions have been created. Pressure testing the nonpotable system should be completed before connection to any existing system. This is frequently accomplished by testing against a blank (a closed valve or blind flange) at the main valve. All backflow-prevention devices must be installed on the potable and fire-protection systems, tested in the field, and ready for service. Before final acceptance of the system, the potable-water services should be shut off; and all fixtures, hose outlets, and other connections designed to remain on the potablewater system should be opened. The nonpotable-water system should then be pressurized and a dye injected into the nonpotable system. The nonpotable system then should be activated and the dye water observed at all intended nonpotable-water outlets. Potable outlets should also be cross-checked to ensure that no dye is present. Inspecting the construction of a nonpotable-water system is most critical at the points of connection and tie-ins. The system should be tested using potable water prior to connection to the main supply. This can be done against a closed valve. When the system passes pressure and leakage tests, the blank can be removed. The location of the connection point must be inspected and approved by the nonpotable-water purveyor or in the presence of the purveyor’s inspector. The inspection protocol should be defined in the purveyor’s System Operational and Maintenance Protocol Manual. The inspector will be responsible for strict adherence to the procedure at all times and monitor the user sites to ensure compliance with all state and local regulations. In addition to the inspections before the system is put into service, periodic inspections should be performed to ensure ongoing compliance with state and local regulations. The inspector should routinely monitor neighborhoods and user sites looking for conditions such as runoff, ponding, and unacceptable overspray of the resource to street surfaces, sidewalks, and neighboring properties. All inspections should be documented and the property owner notified of the visit and findings. It is further recommended that additional inspections occur when the property changes ownership.

Record Drawings Facility plans and distribution system drawings should be maintained and kept up-to-date by the engineering section of the purveyor. Additional information that should be maintained with these records includes service connection details and if applicable, Global Positioning System (GPS) coordinates and Geographic Information System (GIS) databases. This type of information becomes useful as the system ages and provides assistance to field staff performing routine and periodic maintenance. This should be a requirement of the use permit, with all modifications or additions to the system noted. The date of the revision should be indicated on the drawings, and copies of each drawing should be kept at the nonpotablewater purveyor for each revision. Plans should show the location of all nonpotable- and potable-water pipelines, valves, regulators, meters, backflow-prevention devices, hydrants, signage, and other system components. The distributing purveyor should have a system map of the nonpotable system showing the location of all potable- and nonpotable-water lines, valves, regulators, hydrants, blowoffs, meters, air-release valves, and other components. Drawings should include the location of all nonpotable-water services, service size, meter number, and user permit number.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

82

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Customer Site Documentation The purveyor should develop files containing the background documents for each of its customer sites. Documents to be included in the file may start with the letter of intent from the customer. The letter of intent provides information on the intended use for the water. In many cases the use is broad ranged including, but not limited to, urban and agricultural irrigation, cooling towers, machinery operations, toilet flushing, salinity barrier, and other industrial applications. The purveyor should determine whether or not the intended use meets the criteria of the operating permit and whether or not the treatment process and water quality meet the customer’s needs. The purveyor may need additional information, such as instantaneous demand and usage rate data, water-quality criteria, and detailed engineering drawings to determine whether or not the application is appropriate. Other documents may be needed such as legal description of the customer sites, owner’s names, responsible agents, service request date, application date and site application date, site inspection reports, agreements, records of infraction, violation of compliance, customer notifications, and any other correspondence related to the customer site.

UNDERSTANDING CUSTOMER NEEDS AND REQUIREMENTS______ Managers of nonpotable-water systems must be extremely attentive to operating their systems as businesses. The demand for the product and services of nonpotable-water purveyors is not as inherent as that of potable-water purveyors. As a result, understanding customer needs and requirements is extremely important for the success of a nonpotablewater system.

Obtaining Public Support Understanding customer needs and requirements begins with a proper planning effort for obtaining public support and obtaining/maintaining consumer confidence. Typically, an objective for reclaimed-water systems is to develop and sustain a high demand for nonpotable water as a means to decrease demand for potable-water resources. This need for obtaining public support is critical for the success of a nonpotable-water system. Informed consumers are absolutely essential in obtaining support for the development of a reclaimed-water system. The public education program should be ongoing, making use of audio and visual technology, and other available means.

Obtaining/Maintaining Consumer Confidence Obtaining and maintaining consumer confidence and public support is essential if the dual distribution program is to succeed. It begins with the planning phase of program development. The potential for opposition to the development of a dual distribution system has to be addressed before it becomes an issue. The purveyor has to work with community leaders and health officials to build a positive image of reclaimed water. Public health and safety assurances should be one of the most important areas to be addressed. Surveys have indicated little opposition to reuse for park, lawn, or golf course irrigation, or industrial application (Bruvold 1984). The presumption is that such uses are safe. Questions of safety arise initially from public health agencies concerned about how proposed uses may create the potential for disease transmission by cross-connections or direct contact. Reuse for drinking or bathing must be differentiated from reuse for outside irrigation. Consumers asked to support a reclaimed-water system and to use the water must be convinced that the product will not, in any way, endanger their health or well-being. Example talking points might include:

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

MANAGEMENT •

83

Reclaimed water should be promoted as a valuable tool for creating an abundant supply;

•

Reclaimed water helps keep the grass greener;

•

Reclaimed water reduces fertilizer usage;

•

Reclaimed water can provide water features;

•

Reclaimed water is a reliable supply;

•

Reclaimed water is reliable even in drought.

Examples of successful nonpotable-water programs should be presented to enhance the positive image of dual distribution systems (Figures 6-1, 6-2, and 6-3). Information regarding the proposed project must be accurately relayed to the public, voters, and potential users. It is essential that they be given complete and factual information concerning water quality that must meet or exceed all health purveyor requirements. The total cost of the project and the financing should be presented to the various groups using the system. Currently, there are many successful nonpotable distribution systems across the United States that can provide aid and assistance to facilitate development of new applications. The successful experiences of other similar facilities can promote consumer confidence and public support. The use of news media, flyers, informational mail-outs, and community and town hall meetings in conjunction with the information from other communities enhances the level of consumer understanding and acceptance for the nonpotable-water system. The water-reclamation facility should be designed, maintained, and operated in such a manner that the effluent has demonstrable excellence. A continuous public information effort should emphasize that excellence so that the community takes pride in the plant and the water it produces. Local school districts should be encouraged to include in their curriculum the study of water supply and wastewater disposal and reclamation. Tours of the wastewater-treatment or water-reclamation plant should be a standard part of the curriculum for the targeted age level. Tours by service clubs, garden clubs, and any other local organizations should also be encouraged. This continual effort helps to ensure a positive feeling about the quality of the water produced by the plant. Several examples of public relations materials have been developed by AWWA, WEF, WRA, and long-term, well-established nonpotable distributing water agencies. These sources of information should be consulted to assist in the development of a public relations program. A general approach for the development of a public relations program includes the following steps: •

•

Identify potential affected public and stakeholders; Define the scope of the public involvement (will they be allowed to make the final decision?);

•

Conduct issues assessment with key stakeholders;

•

Assess public opinion; and

•

Develop a tailored program for continuous stakeholder involvement.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

84

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

Figure 6-1

Cemetery watered with reclaimed water

Figure 6-2

A baseball field maintained with reclaimed water

Figure 6-3

Xeriscape watered with reclaimed water at a high school --`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

MANAGEMENT

85

ESTABLISHING A VIABLE CUSTOMER BASE ____________________ One of the key tasks of nonpotable-water purveyors is to establish a viable customer base. To accomplish this, the nonpotable-water purveyor must establish a long-term reclaimedwater market plan with the focus on eliminating the current barriers to water reuse and promoting the value and benefits of using reclaimed water. The barriers to the use of reclaimed water include: •

Reclaimed water viewed as low quality;

•

Limited understanding of the value of reclaimed water; and

•

Lack of vision.

The value to the consumer of reclaimed water is often misjudged. Reclaimed water is, by generally accepted standards, of reasonable quality and is “manufactured” for the specified usage—irrigation, industrial, etc. The lack of vision regarding the value of reclaimed water is often based on the limited understanding of the value of reclaimed water. The public generally has little idea of how the use of reclaimed water can ultimately save a community money because it has multiple uses that can supplement the use of potable water. The value and benefits of using reclaimed water include: •

An abundance of water provides recreational benefits, aesthetics, and local and national economic health;

•

Provides an alternative to the potable-water supply; and

•

Reclaimed-water supply is drought-proof.

The nonpotable-water purveyor should convince customers that potable water is not always the best quality for all uses. It should also be made clear that the value of reclaimed water varies with its intended use and on many occasions, reclaimed water is the best quality for the use. For example, using reverse osmosis (RO) treated reclaimed water as boiler feed minimizes scaling and is of better quality than potable water. The fundamental principals of the development of a market for reclaimed water are further discussed in Chapter 7.

SERVICE CONNECTIONS ____________________________________ Nonpotable-water system managers should establish an application and permitting procedure for customer service connections. The application procedure should conform with the nonpotable distributing purveyor’s rules and regulations, and with applicable federal, state, and local statutes, ordinances, regulations, contracts, and other requirements. The permitting procedure should require the user to adhere to the requirements prescribed by the nonpotable distributing purveyor’s rules and regulations and to any additional requirements established by federal, state, or local regulators pertaining to nonpotable-water service.

Application Procedure A procedure should be established for application for service of nonpotable water. This procedure can be very similar to that used for potable-water service. The established procedure should conform with the nonpotable distributing purveyor’s rules and regulations, and with applicable federal, state, and local statutes, ordinances, regulations, contracts, and other requirements. The procedure should provide the customer with an opportunity to review the policies and regulations that govern the nonpotable system. The procedure should clearly outline for the customer the need for on-site inspection without prior notification and provide assurances that these inspections will be conducted at reasonable times of the day. The purveyor establishes acceptable uses of nonpotable water, which may include

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

86

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

landscape irrigation, agricultural irrigation, construction water, industrial process water, toilet flushing, air conditioning, and recreational impoundment. The purveyor should require all detailed site drawings, the letter of intent, and design information at the time the customer application is forwarded to the authorized agent. If applicable, the purveyor may require a demonstration or additional justification to clarify the customer’s request and proposed use. The purveyor should have in place a standard approval procedure; however, it should reserve the right to approve or disapprove additional uses on a case-by-case basis. An application for nonpotable-water service should be made in writing and signed by the applicant. A standard application form should be prepared by the distributing purveyor and should specify the following:

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

•

A description of the property to be served;

•

The applicant’s relationship to the property (as owner or tenant);

•

The purpose for which the property is to be used;

•

End use;

•

The estimated nonpotable-water demand;

•

Delivery requirements with regard to desired pressure and time of day; and

•

Water-quality requirements.

The purveyor may find it desirable to require the applicant to obtain prior approval of the proposed use by federal, state, or local agencies that have jurisdiction.

Permits The issued permit should require the user to adhere to the requirements prescribed by the nonpotable distributing purveyor’s rules and regulations and to any additional requirements established by federal, state, or local regulators pertaining to nonpotable-water service. The permit should also set forth the conditions for temporary or permanent interruption of service due to circumstances beyond the control of the purveyor, but necessary to protect the facilities of the purveyor or the public health, safety, and welfare. Examples when termination may be necessary include the following: •

•

The user’s operations do not conform to the applicable requirements; and The purveyor’s reclamation plant does not meet the requirements of regulatory agencies. Reclaimed-water service would, in such case, be renewed when the reclaimed water again meets the requirements of regulatory agencies or when the purveyor supplements the reclaimed-water system with sources other than the reclamation plant.

The permit should establish maintenance responsibilities. The distributing purveyor should not be liable for any damage resulting from defective plumbing or for broken or faulty services caused by the user. The user should be required to accept the conditions of pressure and service as are provided by the distribution system at the location of the proposed service connection. The purveyor should not be responsible for damage arising from low-pressure or high-pressure conditions or from interruptions of service. Each user should be responsible for designing its system to accommodate the overall requirements of the retailing purveyor. If meters are to be provided for each user, a system should be established to manage modifications that might take place on the user’s system following the meter. The distributing purveyor may want to reserve the right to limit the area of land being supplied nonpotable water to one service connection and one nonpotable-water meter per one ownership. If a property provided with a nonpotable-water service connection and nonpotable-water meter is subdivided, the connection and meter could be considered as

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

MANAGEMENT

87

serving the lot or parcel of land that it directly or first enters. Additional application for reclaimed-water service lines would be required for the new subdivided parcel of land.

SYSTEM OPERATIONS AND MAINTENANCE ___________________ The operation and maintenance of a nonpotable-water distribution system is very similar to a potable-water distribution system except that extra attention must be paid to public safety and health. Visual inspection on a routine basis is necessary to minimize runoff, ponding, or pooling and to eliminate overspray of reclaimed water. Regular monitoring and testing of the system is recommended to guard against accidental cross-connection with the potablewater system.

Monitoring and Testing

Routinely testing the water quality of the system is a good general practice. A sampling for coliform bacteria from a cross section of the system should be made regularly. Broken sprinkler heads, leaks, unreliable valves, or other components should be repaired as quickly as possible. A testing program of the system for inadvertent cross-connections should be established. This testing program can be one of two types, a pressure test or a color test. The pressure test is the most reliable but can be the most difficult to perform. The system should be tested about once a year. Portions of the nonpotable system should be isolated for testing purposes. The pressure test consists of turning off the main supply to the nonpotable system and verifying that water is not flowing to any individual systems. If possible, the procedure should be repeated with the potable system off and the nonpotable system on. This can be difficult, if not impossible, if water is being supplied to a residential area for landscape irrigation. The dye test consists of putting a nontoxic dye into the nonpotable system and checking for the dye in the potable system. This test is not as reliable as the pressure test because small cross-connections may not be detected. A small volume of nonpotable water may become very diluted when introduced into the potable system.

Emergency Connections to the Potable-Water System The nonpotable purveyor may approve a temporary connection to the potable-water system if all or a portion of the nonpotable-water system is out of reclaimed-water supply. Before such a temporary connection is made, the nonpotable portion of the system without reclaimed water should be isolated by an air-gap separation from the remainder of the reclaimed-water system. Backflow prevention that meets applicable regulations must be installed on the potable-water line. The emergency connection should be removed before the system is reconnected to the remainder of the nonpotable system.

Safety The purveyor should guide and supervise the consumer during startup and initial operation to ensure the proper use of nonpotable-water systems. In most cases, if reclaimed water is properly used, continual supervision is not needed. At all times, however, the distributing purveyor must be able to solve any problems that may arise. Worker safety should be ensured. An education program to inform all purveyor personnel, especially maintenance personnel, that reclaimed water is present and should not be ingested is essential. A program should also be established to conduct or assist each user with an education program for their employees (such as a golf course maintenance staff). Table 6-2 presents Hawaii’s guidelines for worker safety.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

88

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

The level of public education and public safety programs should be in proportion to the potential exposure and risk to the public. A procedure to notify the public in case of system contamination should be established and coordinated through the local emergency management purveyor and local or state Board of Health.

Table 6-2 Guidelines for workers’ safety (Adapted from Hawaii State Department of Health Wastewater Branch Guidelines) An Employee Training Plan shall be made for workers who handle or may be exposed to R-1 and R-2 water. 1.

2. 3.

Workers shall be notified that recycled water is in use. Notification shall include the posting of conspicuous, informational signs with wording of sufficient size to be clearly read at the work place. When a worker’s primary language is not English, the notification shall be provide in a form the worker understands. Workers shall be informed verbally and in writing that recycled water is not suitable for ingesting and that drinking recycled water may result in potential illness. Potable water shall be supplied for workers for drinking and washing hands and face. When bottled water is provided, the water shall be in a separate, boldly labeled, contamination-proof containers protected from recycled water and dust.

The following provisions, cited in items (1) through (5), shall be made for workers who handle or may be exposed to recycled water other than R-1 and R-2 water: 1.

Recycled water shall be managed, and spray and mist of recycled water shall be controlled to minimize contact with workers.

2.

Potable water shall be supplied for workers for drinking and washing hands and face. When bottled water is provided, the water shall be in separate, boldly labeled, contamination-proof containers protected from recycled water and dust.

3.

Precautions shall be taken to avoid contamination of food taken by workers into recycled water use areas. Food shall not be taken into areas still wet with recycled water.

4.

Workers shall be notified verbally and in writing that recycled water is in use and that it is not suitable for ingestion. Notification shall include the posting of conspicuous informational signs with wording of sufficient size to be clearly read. When a worker’s primary language is not English, this notification will be provided in a form the worker understands.

5.

Workers shall be informed verbally and in writing that the recycled water used is not reliably free of organisms that can cause serious illness, and workers shall be informed of precautions and proper hygienic procedures to protect themselves. The employer or supervisor of workers shall instruct the workers to comply with the following: a.

Workers shall wash hands with soap and water before eating, drinking, and smoking, and at the end of the work period, and shall not stand where visible mist is present.

b.

Gloves that are impermeable to water shall be worn if contact between hands and recycled water would otherwise occur.

c.

Employees shall keep fingers and hands away from the nose, mouth, and eyes, if fingers and hands have contacted recycled water.

d.

Workers with cuts or breaks in the skin shall cover the area with waterproof bandages or other waterproof cover before working with recycled water.

e.

Employees should be informed that inanimate objects, such as clothes or tools, can transport pathogenic organisms.

f.

Employees should be required to wear shoes or boots at all times to protect their feet from pathogenic organisms in the soil or irrigation water.

Employee training shall include a plan describing the training that the employees will receive to ensure compliance with the Water Reclamation Guidelines. The plan shall identify the entity that will provide the training and the frequency of training.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

MANAGEMENT

89

REFERENCE ________________________________________________ Bruvold, W.H. 1984. Obtaining Public Support for Innovative Reuse Projects. AWWA Water Reuse Symp. Den-

ver, Colo.: American Water Works Association.

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

This page intentionally blank.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

AWWA MANUAL

Chapter

M24

7 Financial/Economic Issues

OVERVIEW ________________________________________________ Institutional factors that can deter utilities from adopting reuse are varied. L isting them is beyond the scope of this manual; however, matters deal ing with interagency conflicts, liability, public perception, political goals, usage, agreements, interagency agreements, and economics play a significant role.

ECONOMIC FACTORS _______________________________________

Economic factors usually override other planning factors when determining the feasibility of a dual water di stribution system. The three general procedures that define these factors are •

Market assessment

•

Economic analysis

•

Financial analysis

Market Assessment The market assessment determines the demand for reclaimed water and the price that could be charged. Traditionally, consumers are accustomed to the relatively low cost of water when compared with other utilities. Consumers would expect a lower-quality water to cost less than potable water. Successful reuse projects have a price differential of 20 percent to 25 percent from the cost of potable water (Cuthbert and Hajnosz 1999). It should be noted, however, that there are reclaimed-water sales that set rates equal to potable rates as well a s situations where the cost of current water supplies for irrigation are incidental, which makes conversi on to reuse a challenge. To achieve this di fferential a nd maintain an economically viable project may require the allocation of avoided costs, such as reduced raw-water or wastewater treatment. Redistribution of capital a nd operating costs to those that benefit indirectly may also be considered appropriate (Cuthbert, et al. 2003).

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

91

Not for Resale

92

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

The approach for assessing the market for nonpotable water depends on the following two factors (Asano and Mill s 1990; Papadimas, et a l. 2000): •

•

Project purpose: Is the intent to treat and dispose of wastewater or to obtain optimum water supply benefit? User option: Will the use of nonpotable reclaimed water be voluntary or mandatory?

The following are importa nt steps in conducting the necessary market assessment: 1.

Determine the general market area for consideration. Inventory potential users and uses of reclaimed or nonpotable water.

2.

Determine health-related, water-quality requirements and application requirements, such as treatment reliability, cross-connection prevention, use-area controls, and irrigation methods for each type of application of nonpotable or reclaimed water.

3.

Determine regulatory requirements that address nuisance and waterquality problems.

4.

Develop assumptions regarding probable water quality that would be available in the future with various levels of treatment. Compare those water qualities with regulatory and user requirements.

5.

Survey potential reclaimed-water users about a. Specific potential uses. b. Present and future quantity needs. c.

Timing and reliability of needs.

d. Quality needs. e.

On-site facilities required and modifications and the capital invest-

f.

ment required. Changes in operation cost.

g.

Desired water cost savings or rate of return.

h. Plans for changing use of the site in the future. i.

Preliminary willingness to use reclaimed water now or in the future.

6.

Evaluate the relationship between potential demand versus cost, and how this is affected by voluntary versus mandatory use. Pricing differentials may help determine the viability of the reuse and distribution system. This should be determined in t he market analysis. Potential ma rkets for reclaimed water, quality and quantity demands, and present water costs must be determined. The difference between these water costs and the disposal of associated wastewater helps define the viability of all alternatives. To develop the long-term reclaimed-water market plan, the purveyor will need to rely target on some basic marketing principles. First, the purveyor will have to consider its market for reclaimed water. Some of the target markets to be considered are the potential users discussed i n Chapter 1 and include the following broad markets:

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

•

Water resources market

•

Industrial reuse market

•

Habitat/restoration market

•

Turf irrigation market

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

FINANCIAL/ECONOMIC ISSUES

93

Once the target markets have been selected, the purveyor will need to develop a marketing strategy to position the reclaimed water i n the ma rketplace. The purveyor should consider the concept of branding the reclaimed water for consumer appeal. As the marketing strategy is developed, the purveyor will also have to consider what is referred to as the marketin g mix, which consists of four elements of marketing that are used in combination to achieve the market objectives in a selected target market. The ma rketing mix consists of the following elements, and Figure 7-1 shows an illustration of the marketing mix related to reclaimed water: •

Product – tailored to meet consumer needs

•

Price – cost market/consumer will accept

•

Place (distribution) – geographical proximity and attractiveness

•

Promotion – communication with customers

The flow diagram shown on Figure 7-2 may assist a pur veyor to begin the process of creating a water reuse ma rket.

Economic Analysis The role of an economic analysis is to provide a monetary basis for justifying a dual distribution system. A project is considered justified if its total benefits exceed its total costs (Asano and Mills 1990). Economic evaluations involve an analysis of alternatives to the use of reclaimed water in a dual distribution system. Costs of alternative potable-water source development and treatment must be determined from local and regional agencies. In addition, the analysis should identify beneficiaries by such user classes as agricultural, industria l, or municipal as well a s the quantity requirements and quality of selected use. Indirect benefits include •

Augmentation of water supply to meet regional demands;

•

Improvement of wastewater effluent discharge quality and receiving water

•

quality; and Regional economic growth and development.

At this stage, preliminary discussions with users and the results from analyses should determine the value of these benefits and costs to indirect users. On the downside, a water utility may have to raise water rates to cover fixed costs if expected revenues are not realized because of i ncreased reuse consumption . After the market asses sment for a dual water distribution system is completed, the existing and potential serv ice area of the dual water distribution system and quantity and quality of reclaimed water available can be determined. Based on the water quantity and quality, location of sources, and demand requirements, the conceptual physical layout of dual water distribution systems—from source to distribution—can be established (see chapter 3). Once the alternative configurations of dual and conventional water systems are identified, estimated costs of both systems should be developed to determine the costeffectiveness of the dual water distr ibution systems. The planning-level cost estimates can be derived from generalized cost curves or cost equations (Deb 1978; Asano 1998). To determine the cost of reclaimed water, the costs of additional t reatment, storag e, and di stribution should be considered. It is necessary to add the costs of meters, cross-connection control measures, internal pipes, and the cost of meeting more stringent wastewater effluentretrofitting discharge of requirements. Once all the costs of various unit processes required for a water-reuse system are analyzed and selected, and capital costs and operating and m aintenance (O&M) costs are estimated, a total annual cost can be calculated (Deb 1978; Asano 1998) . Annual costs for

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

94

PLAN NING FOR THE DISTRIBUT ION OF RECLAIMED WATER

a dual di stribution system and the corresponding conven tional system could then be compared to deter mine t he cost-effectiveness of the dua l water distribution system.

Figure 7-1

Water reuse marketing mix

Figure 7-2

Creating a water reuse market

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

FINANCIAL/ECONOMIC ISSUES

95

Financial Analysis The result of the economic analysis determines whether or not a dual water distribution system should be constructed. Equally important is the question: Can a dual d istribution system project be constructed? A financial a nalysis provides answers. A dual water distribution system needs a source of capital and revenues to pay for debt service and operational costs for both the proposed dual-system project and any existing facilities. Fixed costs for existing facilities, although irrelevant in the economic analysis, must be considered in a financial analysis if they are a continuing financial obligation. Users of the reclaimed water will expect the net cost for the reclaimed water to be no more than would have been paid for potable water. For example, a reclaimed-water customer may have to invest in piping or sprinkler modifications to properly use the reclaimed water. The sale of reclaimed water may reduce revenue from potable-water sales. The effect on the potable-water retailer and potable-water prices should be evaluated. Potential users often have different sources of water or different rate schedules. It is important not to assume that there is an average price that all users are paying. Failure to take into account the financial situation of each user could result in the loss of key reclaimed-water customers. The initial market assessment should include this financial data (Asano and Mills 1990). Dual water distribution systems provide both direct and indirect benefits. If reclaimed wastewater is the source of the nonpotable water, then indirect benefits to the user and the wa stewater-treatment purveyo r may be sign ificant. For example, The Citrus Growers Association uses reclai med wastewater from Orlando, Fla., that conta ins nitrogen. They save $100 to $200 per acre, per year ($40 to $80 per hectare per year) that would have been spent on nitrogen fertilizer. In addition, the cost of pumping water into the citrus groves ranged from $75 to $150 per acre, per year. This cost is also eliminated. By using reclaimed water, the growers are exemp t from consumptiveuse limitations i mposed by the state of Florida. The city of Orlando also benefits because it did not have to buy or lease 15,000 acres of land for the disposal of treated wastewater. Indirect benefits also a ccrue to wastewater-treatment utilities. For example, the reclaimed portion of wastewater may not require complete treatment. Thus, plant capacity can be saved. In addition, operation, maintenance, and chemical costs may be saved, especially if chlorination or tertiary treatment is not required. When discharge permits allocate a specific amount to wastewater-treatment plants, an additional flow equal to that portion reclaimed may be received by the plant. For example, if the da ily discharge l imit is 20 mg/L BOD and 833 lb (37.8 kg) BOD, up to 5 mgd (18.9 ML/d) may be discharged. If 2 mgd (7.57 ML/d) were reclaimed, an additional 2 mgd (7.57 ML/d) could be accommodated without exceeding di scharge limits. Indirectly, thi s benefits regions that promote growth.

System Financial Considerations As wit h other water-related serv ices, nonpotable system fina ncial considerations must be well thought out. This section discusses the following nonpotable-wa ter system financial considerations:

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

•

Nonpotable-water rates;

•

Connection fees/capital charges/system development fees; and

•

Plan check and inspection fees.

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

96

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Nonpotable-Water Rates Currently, there is no industry standard approach regarding the development of reclaimedwater rates as there is with water-supply rate setting or the charges a ssociated with wastewater treatment. Reclaimed-wate r rate setting is usually based on the following: •

Conducting a cost of service study

•

Economic analysis

•

Market value

•

Percentage of water pricing

•

Contractual agreements (negotiated)

•

Combinations of the above

Often rates include a fixed component (meter reading, maintenance costs) and a variable component. Other fees or additional fees collected to support a reclaimed-water system include: •

Connection fee/system development fees, etc.

•

Plan check and inspection fees

When a cost of service study is done to determine the rates associated with a particular reclaimed-water project, the study often uses the rate setting practice in water supply. The water supply field has a rich history in the development of philosophies associated with how much a customer should be charged for being provided safe drinking water. These rate-setting philosophies are captured in two AWWA manual s of water supply practices: AWWA Manual M1, Prin ciples of Water Rates, Fees, an d Charges and AWWA Manual M54, Developing R ates for S mall System s. However, a reclaimed-water cost setting borrows from the philosophies associated with the development of wastewater treatment charges. Those philosophies are captured in the Water Environment Federation (WEF) Financing and Charges for Wastewater Systems . When an economic analysis is done to dete rmine the rates associated with a pa rticular reclaimed-water project, it is often compared against the current cost of potable-water supply. The analysis takes into consideration the cost associated with the next incremental source of supply. The resulting reclaimed water is often a percentage of the prevailing drinking water rate. In this analysis, it is important not to confuse water cost and water price. The cost of water includes all the costs associated with the next incrementa l source of water supply; the price of water is based on one of the previously discussed water-rate setting philosophies. It is also important to compare the rates for equivalent use rates. For example, most municipal rate structures use an increasing block or conservation water-rate structure. Because residential reclaimed water is almost exclusively used for external irrigation, which is the highest price in the conservation rate block, it is important to compare residential rates. However, the comparison must be of the irrigation block rate and not the base block rate. The procedure f or establishing rates for nonpotab le water can be simi lar to the di stributing purveyor’s procedure for establishing potable-water and sewer rates. The nonpotable water should be metered, and a meter charge usual ly fi xed by meter size can be imposed. At times, the nonpotable-water rate is established at a percentage of the potablewater rate to create incentives for using reclaimed water. Nonpotable-water rates set at 25 to 100 percent of the cost of potable water are common. Recently, some utilities have conducted a market assessment to determine the market value of reclaimed water. In some cases, based on the market value of some designer

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

FINANCIAL/ECONOMIC ISSUES

97

reclaimed waters (for example, reclaimed water developed for boiler feedwater requiring RO treatment), the price charged for the reclaimed water has been twice as much as potable water. The concept is to determine the added value associated with reclaimed water when compared to other sources of supply and have the market pay for that value. The elements of value that have enabled utilities to charge more for reclaimed water than potable water are a combination of characteristics. Those characteristics include the public’s perception of the identity of the reclaimed water (branding), the water supply problem that the reclaimed water solves, what source of supply the reclaimed water is being compared to, and the magnitude of the public percep tion of risk. In certai n markets, consumers will pay a premium for a highly reliable water resource of consistent quality to meet end use needs. In the end, this ty pe of reclaimed-water rate setting is driven by marketing principles. Other methods of setting nonpotable-water rates, such as a contract agreement through negotiation with the user or setting the rate at market value of the nonpotable water, are also used. In reality, combinations of the previously mentioned methods are often used. It should be noted that currently both potable water and nonpotable water are undervalued in the United States. Both potable- and nonpotable-water rates will have to reflect their real cost to ensure the long-term fina ncial viability of these systems.

Connection Fees/Capital Charges/System Development Fees Connection fees, also known as capital charges or system development fees, may be collected to pay for capital construction of all or a portion of the distribution system. Connection fees can also be used as a credit against the cost of developing future potable-water sources or wastewater-disposal systems and may be derived from the water and sewer connection fees. As an alternative to collecting a connection fee, consumers can pay to construct nonpotablewater facilities and receive a credit or a reimbursement on water or sewer fees.

Plan Check and Inspection Fees Fees incurred to have drawi ngs (plans) check ed and in spected can be u sed by the water utility to ensure compliance with design and construction standards. These fees may be collected as an hourly rate, a percentage of the construction value of the facilities, or other methods deemed appropriate.

INSTITUTIONAL ISSUES _____________________________________ Interagency Conflicts Obstacles that dual water distribution systems encounter often involve interagency conflicts. Opposition from other municipal or private water purveyors can arise when reclaimed water is priced such that demand for potable water decreases (Asano 1998). State or local policies on health effects can be so stringent as to preclude the use of reclaimed water. Jurisdictional issues related to water rights, consumptive use, and interbasin transfers may limit the service area of dual water distribution systems (Cafaro and Wilson 1984).

Liability Nonpotable-water use in dual water distribution systems has liability aspects. Product liability laws are intended to encourage safe products by shifting the economic cost of injury away from the injured party to others. Liability may a rise from personal or property injury, intentio nal or u nintentional acts, default of expressed or implied warranties, product quality or quantity, or breach of contract.

--`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

98

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

Agreements A necessa ry part of any reclaimed water program is the need to fi nalize comm itments for the use of the reclaimed water (Templeton 2002). Commitments or agreements will be unique to the needs of each supplier, user, and financier. Negotiations will relate to health effects, treatment, storage, and distribution demands. Agreements should be based on research or regulatory standards, available technology fo r control and monitoring, analysis of demands, and the cost of alternative supplies. Key issues that may remain to be negotiated are the payback for capital costs, operations, and maintenance. Evaluation of tangible and intangible benefits and costs to each party is critical when establishing use agreements. Equally critical a re regulatory policies of state a nd federal gove rnments. Contingencies and “what if” scenarios (for example, a large user going out of business) should be developed. Risks a nd costs of alternative supplies should be equally shared.

REFERENCES _______________________________________________ Asano, T. a nd R.A. Mills. 1990. Planning and Analysis for Water Reuse Projects. Jour. AWWA, 82(1):38. Denver, Colo.: American Water Works Association. Asano, Takash i (editor). 1998. Wastewater Recl amation and Reuse. La ncaster, Pa.: Technomic Publishing. Cuthbert, R.W., and A.M. Hajnosz. 1999. Setting Reclaimed Water Rates. Jour. AWWA, 91(8):50. Denver, Colo.: American Water Works Association. Cuthbert, R.W., K. Fowler, A.M. Hajnosz, and A. Griffith. 2003. When Does Re-

claimed Water Use Make Sense? An Econo mic Analysi s of Recl aimed Water Use in Washington State.

AWWA A nnual Conference Proceedings. Denver, Colo.: American Water Works Association. Cafaro, D. and O.M. Wilson. 1984. Short Range Nonpotable Water Management Plan, Colorado Springs, Colo. In Proc. AWWA Water Reuse Symp. Denver, Colo.: American Water Works Association.

Deb, A.K. 1978. Multiple Water Supply Approach for Urban Water Management. Report NSF ENV 76-18499.

Ann Arbor, Mich.: National Science Foundation. Papadimas, S., J. Dettmer, T. Francis, and K. Dotson. 2000. Evaluation of Reclaimed Water System Alternatives for City of Tucso n Using Cyber net Hydraulic Model. AWWA Annual

Conference Proceedings. Denver, Colo.: American Water Works Association. Templeton, C. 2002. Alstyl e Apparel and

Activewear Water Reuse Project.

City of Anaheim Public Utilities, Ana heim, Ca lif. AWWA Water Sources Conference Proceedings. Denver, Colo.: American Water Works Association. WEF. 2004. Financing and Charges for Wastewater Systems. Alexandria, Va.: Water Environment Federation.

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Index NOTE: f.

indicates a figure; t. indicates a table.

Agricultural uses, 42, 79 American Water Works Association (AWWA) Developing Rates for Small Systems (M54), 96 policy on drinking water sources, 2

agricultural uses, 42 aquaculture uses, 42 calculating, 35–36 commercial use, 40

Principles (M1), 96 of Water Rates, Fees, and Charges

construction, cooling-water40 makeup, 41, 41 f. and development plans, 36 estimated daily use per category, 37, 38t. indoor residential use categories, 37, 39 t. industrial uses, 41–42 lakes and impoundments, 41 landscaping irrigation, 40–41 and meter records, 36 municipal uses, 40–41 office and commercial buildings, 40 outdoor residential use, 40 potential reuse demands, 37, 39 t. process rinse and washwater, 41–42 and questionnaires, 36 seasonal variations (S t. Petersburg, Fla.), 51, 51f. urban categories, 37, 37 t.

public relations materials, 83 Water Quality in the Distribution System , 43 Aquaculture uses, 42, 79 Arizona Grand Canyon Village dual distribution system, 2f., 3 Department of Water Resources, 7–8 reclaimed water legislation, 7–8

Biodegradable organics, 52 Blowoff safeguards, 70 Buffer zones. See Setback distances California Department of Public Health, 20–21 reclaimed water legislation, 6–7 turbidity requirements, 17 Water Recycling Criteria, 20 Capital charges, 97 f. Cedar Bay Power Plant (Jacksonville, Fla.), 41 Central Arizona Project, 7 Chemical constituents, 14 Chemical revolution, 4 Chlorine residual monitoring, 18 Color coding of system components, 60f., 67–68 Commercial uses, 5, 40, 78 Connection fees, 97 Conservation, 4 Contaminants, 4 Construction uses, 40, 78 Cooling-water makeup, 41, 41f., 78–79 Cross-connection control, 20–21, 66–67 Cryptosporidium, 17–18

and zoning maps, 36 Design, 57, 59 cross-connection control, 66–67, 67 f. and demand management, 57–58 and differing pressure requirements, 59 major structures, 60 pipe materials, 61 pipes, 60, 60 f. pressure, 61 prevention of improper use, 67–70, 68 f., 69f., 70f., 71t. safeguards, 66–72 service connections, 60, 61 f. storage, 62–66 system appurtenances, 61–62, 63 f. system hydraulic modeling, 58–59, 58 t. See also Infrastructure development Developing Rates for Small Systems (M54), 96

Demand management, 57 and on-site storage, 58 and peak demands, 57–58, 59 and user types, 58 Demand projections, 35, 36–37

Disinfection monitoring, 18 Dissolved solids, 53 Distribution systems, 42–43 developing, 44–45

99 Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

100

PLANN ING FOR THE DISTRIBUT ION OF RECLAI MED WATER

drinking water systems with fire protection, 43 nonpotable systems without fire protection, 43 potable systems without fire protection, 43 See also Dual distribution systems Drain valve safeguards, 70 Dual distribution systems, 1, 43, 44f. defined, 1 drivers for, 3–5 history, 2–3 hydraulic modeling, 58–59, 58 t. integrity control, 75 phased construction of, 59 See also Infrastructure development; Operations and maintenance; Service connections Economic considerations. See Finance Emergency connections, 87 Environmental Protection Agency (EPA). See US Environmental Protection Agency Fair, Gordon M., 3 Fecal coliforms, 17, 19 Finance branding, 93 connection fees, 97 economic analysis, 93–94 economic factors, 91–97 financial analysis, 9591–93 market assessment, market value of reclaimed water, 96, 97 marketing mix, 93, 94 f. plan check and inspection fees, 97 rates, 96–97 system financial considerations, 95 target market, 92–93 Financing and Charges for Wastewater Systems, 96

Florida Department of Environmental Regulation, 7 reclaimed water legislation, 7 Food establishment safeguards, 72 Giardia, 17–18

Grand Canyon Village, Arizona, and dual distribution system, 2f., 3

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Groundwater monitoring programs, 19 overdraft, 7 recharge, 79 Groundwater Management Act (Arizona), 7

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Guidelines. See Regulations and guidelines Haney, Paul, 3 Hong Kong, 2, 49 Hydraulic modeling, 58–59, 58t. Industrial uses, 5, 41–42, 78–79 Infrastructure development customer site documentation, 82 plan checking, 79–80 record drawings, 81 site inspection, 80–81 Insurance Services Office, Inc., 43 Irrigation of baseball field, 83, 84 f. of cemetery, 83, 84 f. controller safeguards, 70 of crops, 3, 3 f. of high school xeriscape, 83, 84 f. landscape, 70–72, 78 landscaping demand projections, 40–41 safeguards, 70–72 urban, 3, 40–41 Irvine Ranch (California) Water District, 57 Lakes and impoundments, 41, 78 Limited water resources, 4 Limited water supplies, 4 Management, 73, 74t. agreements, 98 of agricultural uses, 79 of aquaculture uses, 79 of commercial and office building uses, 78 of commercial uses, 78 compliance and enforcement, 75–76 of construction uses, 78 and consumer confidence, 82–83 of cooling-water makeup, 78–79 establishing viable customer base, 85 of groundwater recharge, 79 of indoor residential uses, 77 of industrial uses, 78–79 infrastructure development, 79–82 interagency conflicts, 97 of lakes and impoundments, 78 of landscape irrigation, 78 liability, 97 of municipal uses, 78 of nonpotable uses, 77–79 of outdoor residential uses, 77 philosophy, 73–74

Not for Resale

INDEX

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

policies and procedures manual, 77 of process and wash water, 79 product quality control, 75 protecting public health, 74–76 public education, 76 and public support, 82 and service connections, 85–87 staff training, 76 system integrity control, 75 system policies and procedures, 77–79 See also Finance t. Master plan for reclaimed water, 32–34, 33 Microbial indicator organisms, 17–19 Modeling. See Hydraulic modeling Monitoring compliance point, 18–19 operations and maintenance, 87 requirements, 14–19 stations, 72 Municipal uses, 40–41, 78 National Board of Fire Underwriters, 43 National Interim Primary Drinking Water Regulations, 4 National Research Council, 3 New England Water Works Association, 2 Nonpotable water defined, 1 industrial and commercial uses, 5 public uses,uses, 5, 6 f.6 residential reuse legislation, 6–8 seawater for toilet flushing, 2, 49 sources, 5 North Carolina, reclaimed water legislation, 8 Operations and maintenance, 87 emergency connections, 87 monitoring and testing, 87 safety, 87–88, 88 t. Organic matter, 14, 52 Parasites, 17–18 Park and playground safeguards, 72 Particulate matter, 17, 18 Peak demands, 57–58, 59 Pipes, 60, 60f. appurtenances, 61–62, 63 f. color coding, 60 f., 67–68 materials selection, 61 pipeline identification, 69 separation and regulations, 69–70, 70 f., 71t.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

See also Service connections Plan checking, 79–80 fees, 97 Planning, 31, 46 demand projections, 35–42 distribution systems, 42–45 for established communities, 31 implementation details, 45–46 master plan, 32–34, 33 t. for new and growing communities, 31 service area, 42 supply sources, 34, 34 f., 35f. Plant nutrients, 52–53 Polluted sources, 4 Potable water, defined, 1 Pressure, 61 differing requirements within system, 59 Principles of Water Rates, Fees, and Charges

(M1), 96 Process and wash water, 41–42, 79 Public education and information, 76, 82–83 Raleigh, N.C. meter study, 36 projected reuse demands, 58, 58 t. WaterFest, 76 Rates, 96–97 Reclaimed water, 1 Arizona legislation, 7–8 California legislation, in crop irrigation, 3, 3 f.6–7 defined, 1 and fire-flow requirements, 59 Florida legislation, 7 history, 2–3 master plan, 32–34, 33 t. North Carolina legislation, 8 supply sources, 34, 34 f., 35f. system types, 42–43 treatment, 52–55 treatment classes, 13 in urban irrigation, 3 use area controls, 19–21 uses, 10, 10 t. Reclamation plants centralized facilities, 53 disposal of excess reclaimed water, 55 facility operation, 54 satellite facilities, 53–54, 54 f. Reduced-pressure-backflow assemblies (RPBAs), 66–67, 67f. Regulations and guidelines, 9–10

Not for Resale

101

102

PLAN NING FOR THE DISTRIBUT ION OF RECLAI MED WATER

chemical constituents, 14 compliance and enforcement, 75–76 cross-connection control, 20–21 disinfection monitoring, 18 EPA guidelines, 14, 21–22, 23 t.–27t., 75 microbial indicator organisms, 17–19 monitoring compliance point, 18–19 monitoring requirements, 14–19 organic matter, 14 particulate matter, 17, 18 reclaimed water uses, 10, 10 t. setback distances (buffer zones), 19–20 state regulations, 10–12, 11 t., 12t., 15t.–16t. storage requirements, 21 treatment and quality requirements, 13–14, 15t.–16t. treatment classes, 13 treatment reliability, 19 use area controls, 19–21 Residential uses, 6 indoor, 37, 39 t., 77 outdoor, 40, 77

seasonal demand variations, 51, 51 f. Staff training, 76 State regulations, 10–12, 11t., 12t., 15t.–16t. Storage, 62 and evaporation, 63 on-site by customers, 58 open-storage impacts on water quality, 63–64 operational, 64, 65 f. regulatory requirements, 21 safeguards, 70 seasonal, 62–63 supplemental supply, 65–66 Supply sources, 5, 34, 34f., 35f., 49 hourly variations, 50–51 raw water (untreated or partially treated), 50 seasonal variations, 50, 51–52, 51 f. selecting, 50 stormwater runoff, 50 wastewater, 49–50 Supply, 34, 34f., 35f. Suspended solids, 52 System development fees, 97

Safeguards, 66 and blowoffs and drain valves, 70 color coding of system components, 60 f., 67–68 cross-connection control, 20–21, 66–67, 67 f. and food establishments, 72

Total coliforms, 17, 19 Treatment, 52 basic parameters, 52–53 and biodegradable organics, 52 classes, 13 dissolved solids, 53

irrigation controllers, 70 70–72 and landscape irrigation, monitoring stations, 72 and parks and playgrounds, 72 pipe separation, 69–70, 70 f., 71t. pipeline identification, 69 prevention of improper operation, 70–72 prevention of improper use, 67–70 protecting public health, 74–76 and storage facilities, 70 and valve boxes, 63 f., 70 warning signs, 67, 68 f., 69f. Safety, 87–88, 88t. San Antonio, Texas, 57 Sedgwick, W.T., 2 Service connections, 60, 61f., 85 application procedure, 85–86 permits, 86–87 Setback distances (buffer zones), 19–20 Southwest Florida Water Management District, 7 St. Petersburg, Fla. reclamation plant and storage, 64, 65 f.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

and 53 52–53 and pathogens, plant nutrients, reclamation plants, 53–55 reliability, 19 requirements, 13–14, 15 t.–16t., 23t.–27t. and suspended solids, 52 Ultraviolet (UV) irradiation, 18 Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse, 18

United Nations Economic and Social Council, 2 US Bureau of Reclamation, 7 US Environmental Protection Agency (EPA) Guidelines for Water Reuse, 14, 21–22, 23t.– 27t., 75 National Interim Primary Drinking Water Regulations, 4 US Public Health Service Drinking Water Standards, 4 Valve box safeguards, 63f., 70 Viruses, 17, 18, 19 Warning signs, 67, 68f., 69f.

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

INDEX

Wastewater oxidized, 13 reuse over rigorous treatment, 5 Water Environment Federation (WEF) Financing and Charges for Wastewater Systems, 96

public relations materials, 83 Water Environment Research Foundation (WERF), 64 Water quality chemical constituents, 14 Cryptosporidium, 7–18 disinfection monitoring, 18 dissolved solids, 53 fecal coliforms, 17, 19

Giardia, 17–18 microbial indicator organisms, 17–19 and open storage, 63–64 organic matter, 14, 52 parasites, 17–18 particulate matter, 17, 18 pathogens, 53 plant nutrients, 52–53 product quality control, 75 requirements, 13–14, 15 t.–16t., 23t.–27t. suspended solids, 52 total coliforms, 17, 19 viruses, 17, 18, 19 Water Quality in the Distribution System , 43 WRA, 83

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

103

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

AWWA Manuals

M1,

Principles of Water Rates, Fees, and Charges ,

M27,

Fifth Edition, 2000, #30 001PA M2,

#30027PA

Instrumentation and Control , Third Edition,

M28,

2001, #30002PA M3,

Safety Practi ces for Water Utilities , Sixth

M4,

Water Fluoridation Principles and Practices ,

M5,

Edition, 2002, #30 003PA

M29,

Fundament als ofEdition, Water Utility Capit al 2008, #30029PA Finan cing, Third

Fifth Edit ion, 2004, #30004PA

M30,

Precoat F iltrati on, Second Edition, 1995,

#30030PA

Water Utility Managem ent , Second Edition, Water Meters—Selection, Installation, Testing, and Maintenance, Fourth Edition,

M31,

Distr ibution Syst em Requirem ents for Fire Protect ion, Fourth Ed ition, 2008, # 30031PA

M32,

Computer Modeling of Water Distribution Syste ms, Second Edition, 2005, #30 032PA Flow meter s in Water Supply, Second Edition,

1999, #30006PA M7,

Problem Organisms in Water: Identification and Treatment , Third Edition, 2004, # 30007PA

M33,

M9,

Concrete Pressure Pipe , Third Edition, 2008,

M36,

2006, #30 033PA

#30009PA Steel Pipe—A Guide for Design and Instal lation, Fift h Edition, 2004, #30011PA

M12,

Simplifie d Procedures for Water Examinati on, Fift h Edition, 2002, #30012PA

M38,

Recommended Practice for Backflow Preve ntion and Cross -Conn ection Contr ol,

M41,

M19,

#30017PA

M44,

Fourth Edition, 2001, #30019PA M45,

M25,

Flexible-Membrane Covers and Linings for Potable -Water Reser voirs, Third Edition, 2000,

Construction Contract Administration, First

Edition, 1996, #30047PA M48,

Edition, 2003, #30 023PA Plannin g for the Distri bution of Recl aimed Water, Third Edition, 2009, #30024PA

Rever se Osmosis and Nanofi ltratio n, Second

Edition, 20 07, #30046PA M47,

PVC Pipe—Design and Installation , Second

M24,

Fibergl ass Pipe Desig n, Second Edition, 2005,

#30045PA M46,

Second Edition, 2004, #30022PA M23,

Distr ibution Valves: Sel ection, Inst alla tion, Fiel d Testing, and Mainten ance, Second

Edition, 2006, #3004 4PA

M20, Water Chlorination/Chloramination Pract ices and P rincip les, Second Edition, 2006, #3 0020PA Sizing Water Service Lines and Meters ,

Steel Wate r-St orage Tanks, First Edition,

1998, #30 042PA

Emergency Planning for Water Utilities ,

M22,

Ductil e-Iron Pipe an d Fittings, Third Edition,

2009, #30041PA M42,

Groundwater , Third E dition, 2003, #30021PA

Electr odialysi s and Elect rodialys is Rever sal,

First Ed ition, 1995, #30038PA

Installation, Field Testing, and Maintenance of Fire Hydrants, Fourth Edition, 2006,

M21,

Operational Control of Coagulation and Filtra tion Proce sses, Second Edition, 2000,

#30037PA

Third E dition, 2003, #30014PA M17,

Water Audits and Loss Control Programs ,

Third Edition, 200 9, #30036PA M37,

M11,

M14,

Reha bilitati on of Water Mains, Second

Edition, 2001, #30028PA

2006, #30 005PA M6,

Exte rna l Corrosio n—Intr oduction t o Chemistry and Control , Second Edition, 2004,

Waterborne Pathogens , Second Edition, 2006,

#30048PA M49,

Butte rfly Valves: Torque, Head L oss, and Cavitation Analysis , First Edition, 2001,

#30049PA M50,

Water Resources Planning , Second Edition,

2007, #30050PA

#30025PA

To order any of these manuals or other AWWA publications, call the Bookstore toll-free at 1.800.926.7337.

105 Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` , ` , , ` , , ` ` ` ` ` ` , , , , ` ` ` , , ` -

106

PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

M51,

Air-Relea se, Air/Vacuum, an d Combinati on AirValves, First Edition, 2001, #30051PA

M54,

M52,

Water Conservation Programs—A Planning Manual, First Edition, 2006, #30052PA

M55,

M53,

Microfiltratio n and Ultra filtra tion Membran es for Drinking Wate r, First Edition,

M56,

Develo ping Rate s for Small Syst ems, First

Edition, 2004, #30 054PA PE Pipe—De sign and Inst allat ion, First

Edition, 2006, #30055PA

2005, #30 053PA

Fundament als an d Control of Nitrification in Chloraminated Drinking Water Distri bution Syst ems, First Edition, 2006,

#30056PA

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , ` , ` , , ` -

To order any of these manuals or other AWWA publications, call the Bookstore toll-free at 1.800.926.7337.

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

Related Titles from AWWA Using Reclaimed Water to Augment Potable Water Resources

If your utility is considering nonpotable water reuse to ease water shortages, this book will help you understand all the issues—technical, economic, regulatory, and social—you should know to make informed decisions. No. 20682

Water Reuse for a Sustainable Future DVD

This awardwinning DVD is designed for water providers as a tool to inform communities, water boards, city councils, and other public officials about the positive potential for reuse to create a more sustainable utility and environment. No. 64329

Membrane Treatment for Drinking Water & Reuse Applications: A Compendium of PeerReviewed Papers

This book presents research and case studies published in the field of membrane technology for water treatment and reuse. No. 20625

Water Reuse: Issues, Technologies, and Applications

Written for both academic and professional use, this comprehensive text presents an integrated approach to all aspects of reuse, including public health, water quality, regulations, treatment technologies, process reliability, and implementation issues. No. 20645

American Customer Water ServiceWorks Association Customer Service: 1.800.926.7337 Outside the US and Canada: 303.794.7711 www.awwa.org/bookstore --`,,```,,,,````-`-`,,`,,`,`,,`---

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale

` , , ` ` ` , , , , ` ` ` ` ` ` , , ` , , `

Copyright American Water Works Association Provided by IHS under license with AWWA No reproduction or networking permitted without license from I HS

Not for Resale