1、ANSI/AWWA C655-18(Revision of ANSI/AWWA C655-09)AWWA StandardSMField DechlorinationEffective date: May 1, 2018.First edition approved by AWWA Board of Directors June 14, 2009.This edition approved Jan. 20, 2018.Approved by American National Standards Institute Sept. 1, 2017.Copyright 2018 American W
2、ater Works Association. All Rights Reserved. iiAWWA StandardThis document is an American Water Works Association (AWWA) standard. It is not a specification. AWWA standards describe minimum requirements and do not contain all of the engineering and administrative information normally contained in spe
3、cifications. The AWWA standards usually contain options that must be evaluated by the user of the standard. Until each optional feature is specified by the user, the product or service is not fully defined. AWWA publication of a standard does not constitute endorsement of any product or product type
4、, nor does AWWA test, certify, or approve any product. The use of AWWA standards is entirely voluntary. This standard does not supersede or take precedence over or displace any applicable law, regulation, or code of any governmental authority. AWWA standards are intended to represent a consensus of
5、the water industry that the product described will provide satisfactory service. When AWWA revises or withdraws this standard, an official notice of action will be placed in the Official Notice section of Journal - American Water Works Association. The action becomes effective on the first day of th
6、e month following the month of Journal AWWA publication of the official notice.American National StandardAn American National Standard implies a consensus of those substantially concerned with its scope and provisions. An American National Standard is intended as a guide to aid the manufacturer, the
7、 consumer, and the general public. The existence of an American National Standard does not in any respect preclude anyone, whether that person has approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standard. Amer
8、ican National Standards are subject to periodic review, and users are cautioned to obtain the latest editions. Producers of goods made in conformity with an American National Standard are encouraged to state on their own responsibility in advertising and promotional materials, or on tags or labels,
9、that the goods are produced in conformity with particular American National Standards.Caution notiCe: The American National Standards Institute (ANSI) approval date on the front cover of this standard indicates completion of the ANSI approval process. This American National Standard may be revised o
10、r withdrawn at any time. ANSI procedures require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of ANSI approval. Purchasers of American National Standards may receive current information on all standards by calling or writing the American
11、National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036; (212) 642-4900, or e-mailing infoansi.org.ISBN-13, print: 978-1-62576-289-4 eISBN-13, electronic: 978-1-61300-470-8DOI:http:/dx.doi.org/10.12999/AWWA.C655.18All rights reserved. No part of this publication may be re
12、produced 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, without the written permission of the publisher.Copyright 2018 by American Wa
13、ter Works Association Printed in USACopyright 2018 American Water Works Association. All Rights Reserved. iiiCommittee PersonnelThe AWWA Subcommittee on Dechlorination, which developed revisions to this standard, had the following personnel at the time:Robert J. Gordhamer, ChairR.J. Gordhamer, Measu
14、rement Technologies Inc., Redmond, Wash.D.M. OConnor, Philadelphia Water Department, Philadelphia, Pa.B. Reilley, Massachusetts Water Resources Authority, Boston, Mass.M.L. Wentink, Nebraska Department of Health and Human Services Division of PublicHealth, North Platte, Neb.The AWWA Standards Commit
15、tee on Disinfection of Facilities, which reviewed and approved this standard, had the following personnel at the time of approval:Betsy Reilley, ChairGeneral Interest MembersG. Boyd,*Standards Council Liaison, The Cadmus Group, Seattle, Wash.D.O. Carroll,*Standards Engineer Liaison, AWWA, Denver, Co
16、lo.K.C. Choquette, Des Moines, IowaJ.M. Henderson, CHA Companies, Albany, N.Y.A.A. Rosenblatt, Gordon retained language that apparatus or additives (if any) used for residual testing would be USEPA compliant.3. Created Appendix A, Dechlorination Chemical Reactions (including newTable A3).4. Moved Ta
17、ble 1 and Table 2 to Appendix A (now Tables A1 and A2).V. Comments. If you have any comments or questions about this standard,please call AWWA Engineering and Technical Services at 303.794.7711, FAX at 303.795.7603, write to the department at 6666 West Quincy Avenue, Denver, CO 80235-3098, or e-mail
18、 at standardsawwa.org.Copyright 2018 American Water Works Association. All Rights Reserved. This page intentionally blank.1Field DechlorinationSECTION 1: GENERALSec. 1.1 ScopeThis standard describes procedures, materials, and requirements for the dechlorination of chlorinated or chloraminated water
19、discharges.Sec. 1.2 PurposeThe purpose of this standard is to define the minimum procedures for the dechlorination of chlorinated or chloraminated water being discharged, including regulations, discharge site preparation, sampling and testing of discharge water, various methods of dechlorination, an
20、d dechlorination chemicals.Sec. 1.3 ApplicationThis standard can be referenced in specifications for the dechlorination of low-chlorinated or highly chlorinated water discharges into the environment. The stipulations of this standard apply when this document has been referenced, and then only to dec
21、hlorination. The dechlorination operation shall comply with any applicable permit or local regulatory requirements, as per Sec. 5.1.1.ANSI/AWWA C655-18(Revision of ANSI/AWWA C655-09)AWWA StandardCopyright 2018 American Water Works Association. All Rights Reserved. 2 AWWA C655-18SECTION 2: REFERENCES
22、This standard references the following documents. In their latest edition, they form a part of this standard to the extent specified within the standard. In case of any conflict, the requirements of this standard shall prevail.National Guidelines and Standards Office*Canadian Environmental Quality G
23、uidelines.NSF/ANSI60, Drinking Water Treatment ChemicalsHealth Effects.NSF/ANSI 61, Drinking Water System ComponentsHealth Effects.USEPAWater quality criteria documents.Additional materials relating to activity under this standard include the following: safety data sheets for forms of chemicals used
24、 (provided by suppliers).SECTION 3: DEFINITIONSThe following definitions shall apply in this standard:1. Authority having jurisdiction: Enforcement authority that has the rightto interpret and apply chlorine discharge regulations and laws.2. Chemical dechlorination: Neutralization of chlorine with t
25、he use ofchemicals.3. Chlorine, free: The combined concentration of dissolved Cl2gas,HOCl, and OCl.4. Chlorine, total residual: Chlorine remaining in water after the chlorinedemand has been satisfied.5. Contact time: The amount of time required to complete the chemicalreaction.6. Day: A 24-hour peri
26、od.7. Dechlorination chemicals: Chemicals used to neutralize chlorine in water.8. DPD: N,N-diethyl-p-phenylenediamine. A colorless indicator thatchanges color when exposed to an oxidant (e.g., chlorine).9. Highly chlorinated water: Water containing more than 4 mg/L of chlorine.* National Guidelines
27、and Standards Office, Environment Canada, Ottawa, Ontario, Canada, K1A 0H3.NSF International, 789 North Dixboro Road, Ann Arbor, MI 48105.American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036.US Environmental Protection Agency, Ariel Rios Building, 1200 Pennsyl
28、vania Avenue, NW, Washington, DC20460.Copyright 2018 American Water Works Association. All Rights Reserved. FIELD DECHLORINATION 310. Loss of control: The period at which there is no longer an opportunityto change, adjust, or control the water chemistry.11. Low-chlorinated waters: Waters containing
29、equal to or less than 4mg/L of chlorine.12. Manufacturer: The party that manufactures, fabricates, or producesmaterials or products.13. National Fire Protection Association (NFPA) hazard ratings: Numericalvalues for health, fire, and reactivity, ranging from 0 to 4, with 0 indicating no hazard and 4
30、 indicating extremely hazardous.14. Nonchemical dechlorination: Neutralization of chlorine without theuse of chemicals.15. Potable water: Water that is safe and satisfactory for drinking andcooking.16. Purchaser: The person, company, or organization that purchases anymaterials or work to be performe
31、d.17. Supplier: The party that supplies materials or services. A supplier mayor may not be the manufacturer.18. Wastewater: A combination of the liquid and water-carried wastefrom residences, commercial buildings, industrial plants, and institutions, together with any groundwater, surface water, and
32、 stormwater that may be present.SECTION 4: REQUIREMENTSSec. 4.1 MaterialsMaterials shall comply with the requirements of the Safe Drinking Water Act and other federal regulations for potable water, wastewater, and reclaimed water systems, as applicable. If the material does not meet the chemical, ph
33、ysical, safety, or security requirements of this standard, the supplier shall be notified promptly after observing the noncompliance.Sec. 4.2 Chemical and Nonchemical Dechlorination4.2.1 General. Dechlorination involves changing the chemical form of the existing chlorine compounds to a form that is
34、not detrimental to the environment. In this sense, dechlorination is a chemical process. However, for purposes of this standard, the terms nonchemical and chemical are used to characterize the two basic methods used for dechlorination. In nonchemical dechlorination, no chemicals Copyright 2018 Ameri
35、can Water Works Association. All Rights Reserved. 4 AWWA C655-18are put into the water being dechlorinated. The chemicals or compounds that are involved in the dechlorination process are already present in the local environment to which the water will be exposed before being released into the genera
36、l environment. In chemical dechlorination, a sufficient amount of chemical is added to the water to accomplish the dechlorination before it is released into the general environment.Nonchemical dechlorination should only be used with low chlorine releases, and chemical dechlorination should always be
37、 used with high chlorine release. The decay rate of low-chloraminated water is three to four times slower than that of low free chlorine water. Thus, a nonchemical procedure suitable for low-chlorinated water may not be suitable for similar concentration of low-chloraminated water.4.2.2 Nonchemical
38、dechlorination. The advantage of this method is that it does not involve chemical addition; hence, purchasers do not have to be concerned with the effects of neutralizing chemicals in the receiving waters and environment. Also avoided are cost, health, and safety concerns related to storage, transpo
39、rtation, and handling of these chemicals.The disadvantage of this method is that the time required to dechlorinate is unpredictable and may vary locally, depending on the procedure used. Temperature, organic exposure, and other factors can either accelerate or hinder the neutralization of chlorine.
40、It is important to verify that dechlorination is achieved before “loss of control.”4.2.2.1 Holding tanks or ponds. The chlorine concentration in stored water gradually decreases with time because of aeration, reaction with sunlight, and reaction at the surface of the holding tank or pond.4.2.2.2 Lan
41、d application. Organic and inorganic impurities in soil and pavements exert a significant amount of chlorine demand and can rapidly neutralize chlorine in released waters.4.2.2.3 Groundwater recharge. The discharge of chlorinated water to dry streambeds or to land for groundwater recharge may be all
42、owed, provided the chlorine dissipates before contact with surface water.4.2.2.4 Releases through hay bales and other natural obstructions. Backwash and planned water releases from the distribution system are flowed through hay bales or other obstructions to dissipate chlorine before discharge into
43、storm sewers and receiving waters. Discharge water must be tested to confirm removal of chlorine.Copyright 2018 American Water Works Association. All Rights Reserved. FIELD DECHLORINATION 54.2.2.5 Discharge into storm sewers. Discharging chlorinated water into storm sewers may be an effective way to
44、 dissipate chlorine from some potable water releases. Storm sewers are usually discharged directly into receiving wetlands or streams bearing aquatic life, and the sewers may not have adequate dechlorinating capacity to complete dechlorination before release into such wetlands or streams. The discha
45、rged chlorinated water must be tested upstream of the receiving waters to confirm removal of chlorine.4.2.2.6 Discharge to sanitary sewers. The release of chlorinated water into sanitary sewers is a very safe and effective means of disposing of chlorinated waters in most cases. Most utilities prefer
46、 this method as their first option for releasing chlorinated potable waters and prefer to discharge superchlorinated water into sanitary sewers. However, this requires close coordination with sanitation district officials to minimize any adverse impact to the wastewater treatment plant operations. T
47、he availability of a sanitary sewer near the point of chlorinated water release and the capacities of the sanitary sewer and the wastewater treatment plant to handle the additional load are the primary limitations in this method. Permission and coordination must also be obtained before releasing chl
48、orinated water into sanitary sewers. Caution must be exercised in avoiding potential cross-connection during discharge to sanitary sewers. A backflow prevention device or an air gap method must be used to prevent cross-connection problems.4.2.3 Chemical dechlorination. Chemical dechlorination is a faster a
