1、AWWA Standard SM Phosphoric Acid Effective date: Aug. 1, 2016. This first edition approved by AWWA Board of Directors Jan. 16, 2016. Approved by American National Standards Institute Mar. 9, 2016. ANSI/AWWA B507-16 (First Edition) Copyright 2016 American Water Works Association. All Rights Reserved.
2、ii AWWA Standard This 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 specifications. The AWWA standards usually con
3、tain 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 pub- lication of a standard does not constitute endorsement of any product or product type, nor does AWWA test, certify, or approve
4、 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 the water industry that the product descr
5、ibed will provide satisfactory ser- vice. When AWWA revises or withdraws this standard, an official notice of action will be placed on the first page of the Official Notice section of Journal American Water Works Association. The action becomes effective on the first day of the month following the m
6、onth of Journal American Water Works Association publication of the official notice. American National Standard An 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 manufactur
7、er, the consumer, and the general public. The existence of an American National Standard does not in any respect preclude anyone, whether that person has ap - proved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the stan
8、dard. American 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 encour - aged to state on their own responsibility in advertising and promotional materials or on tags
9、 or labels that the goods are produced in conformity with particular American National Standards. Caution n oti Ce : 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 m
10、ay be revised or 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 publication. Purchasers of American National Standards may receive current information on all standards by calling or writing
11、the American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036; 212.642.4900; or emailing infoansi.org. ISBN-13, print: 978-1-62576-145-3 eISBN-13, electronic: 978-1-61300-370-1DOI: http:/dx.doi.org/10.12999/AWWA.B507.16 All rights reserved. No part of this publicat
12、ion 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, without the written permission of the publisher. Copyright 2016
13、by American Water Works Association Printed in USA hours of work by your fellow water professionals. Revenue from the sales of this AWWA material supports ongoing product development. Unauthorized distribution, either electronic or photocopied, is illegal and hinders AWWAs mission to support the wat
14、er community. This AWWA content is the product of thousands of Copyright 2016 American Water Works Association. All Rights Reserved.iii Committee Personnel The AWWA Standards Committee on Scale and Corrosion-Control Chemicals, which reviewed and approved this standard, had the following personnel at
15、 the time of approval: Robert A. Ryder, Chair General Interest Members J.H. Bambei Jr.,* Bambei Engineering Services, Arvada, Colo. (AWWA) M.S. McFadden, HDR Engineering Inc., Denver, Colo. (AWWA) N.E. McTigue, EE & T Inc., Newport News, Va. (AWWA) D. Orozco, Robert Cole & Associates, Engineers, Saf
16、ety Harbor, Fla. (AWWA) S.J. Posavec,* Standards Group Liaison, AWWA, Denver, Colo. (AWWA) R.A. Ryder, Kennedy/Jenks Consultants, San Francisco, Calif. (AWWA) R.D. Vaidya, Chastain Skillman Inc., Lakeland, Fla. (AWWA) Producer Members H.T. Belcher Jr., Corrtrac Systems Corporation, Currituck, N.C. (
17、AWWA) R. Hartsock, Occidental Chemical Corp., Dallas, Texas (AWWA) C.P. Principi, Carus Corporation, Belmont, N.C. (AWWA) User Members J.D. Musinski, Village of Arlington Heights, Arlington Heights, Ill. (AWWA) R.M. Powell, Pinellas County Utilities, Largo, Fla. (AWWA) Y. Zhang, Long Beach Water Dep
18、artment, Long Beach, Calif. (AWWA) * Liaison, nonvoting Copyright 2016 American Water Works Association. All Rights Reserved.This page intentionally blank. Copyright 2016 American Water Works Association. All Rights Reserved.v Contents All AWWA standards follow the general format indicated subsequen
19、tly. Some variations from this format may be found in a particular standard. SEC. PAGE SEC. PAGE Foreword I Introduction vii I.A Background . vii I.B History . viii I.C Acceptance . ix II Special Issues. x II.A Storage and Handling Precautions x II.B Wastewater Discharge . xii III Use of This Standa
20、rd . xii III.A Purchaser Options and Alternatives . xii III.B Modification to Standard . xiii IV Major Revisions xiii V Comments . xiii Standard 1 General 1.1 Scope 1 1.2 Purpose . 1 1.3 Application 1 2 References 1 3 Definitions . 2 4 Requirements 4.1 Materials . 3 4.2 Chemical Requirements 3 4.3 I
21、mpurities 3 5 Verification 5.1 Sampling . 4 5.2 Test Procedures . 4 5.3 Notice of Nonconformance . 6 6 Delivery 6.1 Marking 6 6.2 Packaging and Shipping 7 6.3 Affidavit of Compliance or Certified Analysis . 8 Table 1 Sample Size Determination for Orthophosphate Analysis 5 Copyright 2016 American Wat
22、er Works Association. All Rights Reserved.This page intentionally blank. Copyright 2016 American Water Works Association. All Rights Reserved.vii Foreword This foreword is for information only and is not a part of ANSI*/AWWA B507. I. Introduction. I.A. Background. Phosphate chemicals are among the f
23、ew recognized chemical substances that can be safely and effectively used as a corrosion inhibitor in potable water. Several forms of phosphate inhibitors are available, one of which is phosphoric acid (H 3 PO 4 , ortho-phosphoric acid, white phosphoric acid). Commercial- or technical-grade phosphor
24、ic acid is a manufactured product principally obtained by the addition of sulfuric acid to phosphate rock that is mostly mined in Florida, Tennessee, and the West in the United States. Food-grade phosphoric acid is generally produced by the electric-furnace method. The reaction: Ca 3 (PO 4 ) 2 + 3H
25、2 SO 4 + H 2 O 2H 3 PO 4 + 3CaSO 4 + 2H 2 O Phosphate Rock Sulfuric Acid Water Phosphoric Acid Gypsum Water of Hydration This typically produces a phosphoric acid concentration in the range of 2832 per - cent with a pH of less than 1.5. Gypsum (CaSO 4 ) is precipitated and removed from solu- tion le
26、aving phosphoric acid, which has the molecular structure: OH HO HO P O Pure anhydrous phosphoric acid is a white solid that melts at 42.35C (108.23F) to form a viscous liquid. The phosphoric acid concentration can either be diluted to 10 per - cent or less, or concentrated by evaporation to concentr
27、ations that generally range from 35 to 75 percent, up to 85 percent. The normal application concentration of phosphoric acid is 50 to 75 percent by weight in water. Currently, there are over 25 chemical manufacturers and suppliers of phosphoric acid that have certification under NSF /ANSI 60 Drinkin
28、g Water Treatment Chemi- calsHealth Effects, and it is widely available throughout North America. Its action as a corrosion inhibitor is often the reaction with the metal on the surface forming a metal phosphate film deposit as follows: * American National Standards Institute, 25 West 43rd Street, F
29、ourth Floor, New York, NY 10036. NSF International, 789 Dixboro Road, Ann Arbor, MI 48105. Copyright 2016 American Water Works Association. All Rights Reserved.viii The metal phosphate film can also have calcium and/or magnesium phosphate precipitates. Typically, these films are not absolute barrier
30、s to corrosion but frequently can reduce corrosion and metal release rates significantly by reducing metal solubility. The NSF/ANSI 60certified maximum concentrations are a function of the phos - phoric acid solution concentration. Metal Chemical Formula Mineral Name Iron Fe 3 (PO 4 ) 2 Vivianite Co
31、pper Cu 3 (PO 4 ) 2 2H 2 O Cupric orthophosphate Lead Pb 5 (PO 4 ) 3 OH Hydroxypyromorphite Acid Concentration Maximum H 3 PO 4Dosage 3035% 2527 mg/L 50% 5% 17 mg/L 7075% 1314 mg/L 8085% 12 mg/L These maximum acid feed concentrations translate to a maximum phosphorus (P) dosage of approximately 3 mg
32、/L. That is the maximum concentration that is common, and the minimum effective dose can be as low as 0.15 mg/L P. It is often necessary to initiate a phosphate corrosion control dosage at relatively high concentrations (e.g., 2 to 3 mg/L as P) to form an initial passivation film in the first month
33、of application, then to decrease the feed in stages of about 25 percent of the maximum in sequential stages every two weeks to a maintenance dosage more in the order of 0.5 to 1 mg/L P. The maintenance dosage may need to be increased during warmer water tempera- tures of summer and decreased in the
34、cooler water temperatures of winter by as much as a 2:1 factor. The corrosion rate may be measured and the phosphate dosage increased or decreased by insertion and periodic testing of metal coupons and/or metal release. Lin- ear polarization probes are available for continuous real-time measurement
35、of corrosion rates. Adjusting inhibitor dosage rates is system specific as there is a wide variation between corrosion rate and metal release. I.B. History. This first e dition of ANSI/A WWA B507 , Standard for Phosphoric Acid, was approved by the AWWA Board of Directors on Jan. 16, 2016. Copyright
36、2016 American Water Works Association. All Rights Reserved.ix I.C. Acceptance. In May 1985, the US Environmental Protection Agency (USEPA) entered into a cooperative agreement with a consortium led by NSF International (NSF) to develop voluntary third-party consensus standards and a certification pr
37、ogram for direct and indirect drinking water additives. Other members of the original consortium included the Water Research Foundation (formerly AwwaRF) and the Conference of State Health and Environmental Managers (COSHEM). The American Water Works Association (AWWA) and the Association of State D
38、rinking Water Administrators (ASDWA) joined later. In the United States, authority to regulate products for use in, or in contact with, drinking water rests with individual states.* Local agencies may choose to impose requirements more stringent than those required by the state. To evaluate the heal
39、th effects of products and drinking water additives from such products, state and local agencies may use various references, including two standards developed under the direction of NSF: NSF/ANSI 60, Drinking Water Treatment ChemicalsHealth Effects, and NSF/ANSI 61, Drinking Water System ComponentsH
40、ealth Effects. Various certification organizations may be involved in certifying products in accor- dance with NSF/ANSI 60. Individual states or local agencies have authority to accept or accredit certification organizations within their jurisdictions. Accreditation of certi- fication organizations
41、may vary from jurisdiction to jurisdiction. Annex A, “Toxicology Review and Evaluation Procedures,” to NSF/ANSI 60 does not stipulate a maximum allowable level (MAL) of a contaminant for substances not regulated by a USEPA final maximum contaminant level (MCL). The MALs of an unspecified list of “un
42、regulated contaminants” are based on toxicity testing guidelines (noncarcinogens) and risk characterization methodology (carcinogens). Use of Annex A procedures may not always be identical, depending on the certifier. ANSI/AWWA B507 addresses additives requirements in Sec. 4.3.2 of the standard. The
43、 transfer of contaminants from chemicals to processed water or to residual solids is becoming a problem of great concern. The language in Sec. 4.3.2 is a recommenda - tion only for direct additives used in the treatment of potable water to be certified by an accredited certification organization in
44、accordance with NSF/ANSI 60. However, users of the standard may opt to make this certification a requirement for the product. Users of this standard should also consult the appropriate state or local agency having jurisdiction in order to 1. Determine additives requirements, including applicable sta
45、ndards. * Persons outside the United States should contact the appropriate authority having jurisdiction. Copyright 2016 American Water Works Association. All Rights Reserved.x 2. Determine the status of certifications by all parties offering to certify prod- ucts for contact with, or treatment of,
46、drinking water. 3. Determine current information on product certification. II. Special Issues. II.A. Storage and Handling Precautions. Phosphoric acid is often available from a supplier in food-grade and technical-grade purities, both of which may be NSF/ ANSI 60certified or equivalent for potable w
47、ater use. The food-grade chemical usually contains fewer impurities than the technical grade. Phosphoric acid should be stored and handled as any typical acid and should be considered hazardous as a corrosive. Protect containers from physical damage. Store in a cool, dry area in closed containers. R
48、efer to the safety data sheet (SDS) available from the manufacturer or supplier for additional information. Phosphoric acid purchased for nonpotable water application does not need to be certified to NSF/ANSI 60 or equivalent. The user also may wish to obtain price quotations from vendors at differe
49、nt acid concentrations. There is often an advantage in hauling and storage volume costs of utilizing higher-strength acids in the 7075 percent range of concentration. However, it is usually more costly for a producer to provide a more elevated acid concentration so that it may be almost a trade-off in chemical costs. Phosphoric acid is typically the least expensive form of phosphate inhibitor chemi- cal because other inhibitors, including mono- and disodium phosphate, zinc ortho- phosphate, and sodium hexametaphosphate, are prepared from the
