AWWA C651-05 PDF
(Revision of ANSI/AWWA C). Copyright © This document is an American Water Works Association (AWWA) standard. It is not a. 1, , AWWA issued the updated ANSI/AWWA C 14 standard, Disinfecting Water Mains, a result of the review that AWWA standards must go through. AWWA Standard for Disinfecting Water Mains – Jun 1, – Ansi/AWWA C DS60 Water Supply Distribution Standard – Pipelines Other.
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The chlorinated water shall be retained in the main for at least 24 hr, during which time valves and hydrants in the awa section shall be operated to ensure disinfection of the appurtenances.
American National Standards are subject to periodic review, and users are cautioned to obtain the latest editions. After 30 min, fill line and sample as described in Sec. Yarning or packing material shall consist of molded or tubular rubber rings, rope of treated paper, or other approved materials.
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Potable water may be supplied from a temporary backflow-protected connection to the existing distribution awwaa or other supply source approved by the purchaser. As an optional procedure, if required by the purchaser, water used to fill the new main shall be supplied through a temporary connection that shall include an appropriate cross-connection control device, consistent with the degree of hazard, for backflow protection of the active distribution system see Figure 1.
Sealing material or gaskets shall be handled in a manner that avoids contamination. The purpose of this change is to consider the balance between public health, improved test methods, and timely work completion.
Form of chlorine to be used Sec. Note that the procedures explained in Sec. Revisions were approved on Sept. Additionally, any accessible upstream and downstream interior of the existing pipe should be disinfected by swabbing or spraying with aawwa minimum 1 percent chlorine solution.
Before approving a main for x651-05, take an initial set of samples and then resample again after a minimum of 16 hr using the sampling site procedures outlined. In the absence of a meter, the rate may be approximated using a Pitot gauge in the discharge, measuring the time to fill a container of known volume, or measuring the trajectory of the discharge and using the formula shown in Figure 2.
Aawwa 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, without the written permission of the publisher. Samples shall be tested for bacteriological quality in accordance with Standard Methods for the Examination of Water and Wastewater and shall show the absence of coliform bacteria.
Lucie County Department of C6651-05. The vacuum-operated chlorinator mixes the chlorine gas in solution water; swwa booster pump then injects the chlorine solution into the main to be disinfected.
Factors to consider when choosing a method should include the length and diameter of the main, type of joints present, availability of materials, equipment required for disinfection, training of the personnel who will perform the disinfection, and safety concerns. If allowed by local regulations, the pipeline may be returned to limited service prior to obtaining bacteriological results with proper notification of the affected customers. Reaction of Group 7 non metals with metals. Aawa chlorine concentration is uniform throughout the main.
Approval requirements before use.
In some cases, situations become catastrophic where there is a pipe blowout and a loss of water pressure prior to shutdown, requiring disinfection procedures equivalent to those of a new main installation. Where necessary, federal, state, local, or provincial regulatory agencies should be contacted to determine special provisions for the disposal of heavily chlorinated water. Also, this method reduces the volume of heavily chlorinated water to be flushed to waste. Fill rate must be carefully controlled to ensure tablets do not come loose from pipe.
AWWA C Disinfecting Water Mains
If the initial disinfection aawwa to produce satisfactory bacteriological results, or if other results indicate unacceptable water quality, the main may be reflushed and shall be resampled. Samples for bacteriological analysis shall be collected in sterile bottles treated with sodium thiosulfate, in accordance with Section —Samples of Standard Methods for the Examination of Water and Wastewater.
This timing is sufficient to allow bacterial regrowth within the line if there was a contamination problem and provides more flexibility in the scheduling of various work activities. Hoses and fire c65-105 are not recommended for the collection of samples that will be used to make decisions on the bacteriological quality of drinking water. The cleaning method used shall not force mud or debris into the interior pipe-joint spaces and shall be acceptable to the purchaser.
Nonetheless, the repair work needs to be accomplished using sanitary and safe procedures by well-trained crews with proper supervision and guidance. It should be noted if the line is depressurized or opened to the environment prior to or during repair, the sanitary integrity of the pipe is compromised and it is critical to follow sanitary procedures throughout the repair—not just as it is being returned to service.
Record the total number of drops used and the final chlorine reading obtained that is, the chlorine reading of the matched standard.
Flushing velocities of 5fps can be achieved at the following minimum flows4diameter gpm6diameter gpm8diameter gpm10diameter Between the time the satisfactory bacteriological sample results are received and the time that the connection piping is installed, the ends of the piping must be sealed with plastic wraps, watertight plugs, or caps.
After following the appropriate methods above, prior to returning the pipe to service, the efficacy of the disinfection procedure shall be verified by testing for the absence of coliform bacteria.
The Water Main O n Feb. Details of other federal, state or provincial, and local requirements Section 4. Calcium hypochlorite tablets 5-grams shall be placed in the upstream end of each section of pipe to be disinfected, including branch lines.
Disinfection of Water Distribution Systems. Individual states or local agencies have authority to accept or accredit certification organizations within their jurisdictions.
The flushed water should run visually clear, have a measurable chlorine residual if the system operates with a residual, and be checked with bacteriological testing. Determine additives requirements including applicable standards. Option A samples are 16 hr apart, and Option B samples are 15 min apart after a hr rest period foreword II. This page intentionally blank. 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.
AWWA standards describe minimum requirements and do not contain all of the engineering and administrative information normally contained in specifications. The tablet method cannot be used unless the main can be kept clean and dry.
AWWA C651-14 Disinfecting Water Mains
Samples shall be taken of water that has stood in the new main for at least 16 hr after final flushing has been completed. This procedure must not be used on solvent-welded plastic or on screwed-joint steel pipe because of the danger of fire or explosion from the reaction of the joint compounds with the calcium hypochlorite.
The repair site is exposed and the trench is adequately dewatered so that the repair site can be cleaned and disinfected by spraying or swabbing with a minimum 1 percent chlorine solution. The awsa main is then returned to service with flushing to obtain three d651-05 of water turnover, making sure that the flushed water is visually clear. The slug method results in appreciable savings of chemicals used to disinfect long large-diameter mains. Before approving a main for release, let it sit for a minimum of 16 hr without any water use.